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Surgery_Schwartz. gastrocolic ligament and colonic mesentery. The greater omentum is attached to the anterior/superior edge of the transverse colon. These attach-ments explain the characteristic triangular appearance of the transverse colon observed during colonoscopy. The splenic flexure marks the transition from the transverse colon to the descending colon. The attachments between the splenic flexure and the spleen (the lienocolic ligament) can be short and dense, making mobilization of this flexure during colectomy challeng-ing. The descending colon is relatively fixed to the retroperi-toneum. The sigmoid colon is the narrowest part of the large intestine and is extremely mobile. Although the sigmoid colon is usually located in the left lower quadrant, redundancy and mobility can result in a portion of the sigmoid colon residing in the right lower quadrant. This mobility explains why volvulus is most common in the sigmoid colon and why diseases affect-ing the sigmoid colon, such as diverticulitis,


Surgery_Schwartz

Surgery_Schwartz. the sigmoid colon residing in the right lower quadrant. This mobility explains why volvulus is most common in the sigmoid colon and why diseases affect-ing the sigmoid colon, such as diverticulitis, may occasionally present as right-sided abdominal pain. The narrow caliber of the sigmoid colon makes this segment of the large intestine the most vulnerable to obstruction.Colon Vascular Supply. The arterial supply to the colon is highly variable (Fig. 29-1). In general, the superior mesenteric artery branches into the ileocolic artery (absent in up to 20% of people), which supplies blood flow to the terminal ileum and proximal ascending colon; the right colic artery, which supplies the ascending colon; and the middle colic artery, which supplies the transverse colon. The inferior mesenteric artery branches into the left colic artery, which supplies the descending colon; several sigmoidal branches, which supply the sigmoid colon; and the superior rectal artery, which supplies the proximal


Surgery_Schwartz

Surgery_Schwartz. branches into the left colic artery, which supplies the descending colon; several sigmoidal branches, which supply the sigmoid colon; and the superior rectal artery, which supplies the proximal rec-tum. The terminal branches of each artery form anastomoses with the terminal branches of the adjacent artery and communi-cate via the marginal artery of Drummond. This arcade is com-plete in only 15% to 20% of people.Key Points1 Resection principles: The mesenteric clearance technique dictates the extent of resection and is determined by the nature of the primary pathology, the intent of resection, the location of the lesion, and the condition of the mesentery.2 Function after resection: Bowel function is often com-promised after colorectal resection, especially after low anterior resection. For this reason, it is important to obtain a history of prior anorectal trauma and/or incontinence before considering a low anastomosis.3 Ostomies/Stomas: Preoperative marking for a planned stoma is


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Surgery_Schwartz. For this reason, it is important to obtain a history of prior anorectal trauma and/or incontinence before considering a low anastomosis.3 Ostomies/Stomas: Preoperative marking for a planned stoma is critical for a patient’s quality of life. Ideally, a stoma should be located within the rectus muscle, in a location where the patient can easily see and manipulate the appliance, and away from previous scars, bony promi-nences, or abdominal creases.4 Inflammatory bowel disease: Both Crohn’s disease and ulcerative colitis are associated with an increased risk of colorectal carcinoma. Risk depends on the amount of colon involved and the duration of disease.5 Pathogenesis of colorectal cancer: A variety of mutations have been identified in colorectal cancer. Mutations may cause activation of oncogenes (K-ras) and/or inactivation of tumor suppressor genes (adenomatous polyposis coli [APC], deleted in colorectal carcinoma [DCC], p53).6 Minimally invasive resection: Laparoscopy and HAL have


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Surgery_Schwartz. oncogenes (K-ras) and/or inactivation of tumor suppressor genes (adenomatous polyposis coli [APC], deleted in colorectal carcinoma [DCC], p53).6 Minimally invasive resection: Laparoscopy and HAL have been shown to be both safe and efficacious for colorec-tal resection. Robotic surgery increasingly has been used, especially for rectal/pelvic dissection.7 Anal epidermoid carcinoma: Unlike rectal adenocarci-noma, anal epidermoid carcinoma is treated primarily with chemoradiation. Surgery is reserved for patients with persistent or recurrent disease.8 Rectal prolapse: Rectal prolapse occurs most commonly in elderly women. Transabdominal repair (rectopexy with or without resection) offers more durability than perineal proctosigmoidectomy, but it carries greater operative risk.9 Hemorrhoids: Hemorrhoids are cushions of submucosal tissue containing venules, arterioles, and smooth muscle fibers. They are thought to play a role in maintaining continence. Resection is only indicated for


Surgery_Schwartz

Surgery_Schwartz. Hemorrhoids are cushions of submucosal tissue containing venules, arterioles, and smooth muscle fibers. They are thought to play a role in maintaining continence. Resection is only indicated for refractory symptoms.10 Fistula in ano: Treatment of fistula in ano depends on the location of the fistula, amount of anal sphincter involved in the fistula, and the underlying disease process.Brunicardi_Ch29_p1259-p1330.indd 126023/02/19 2:28 PM 1261COLON, RECTUM, AND ANUSCHAPTER 29Except for the inferior mesenteric vein, the veins of the colon parallel their corresponding arteries and bear the same terminology (Fig. 29-2). The inferior mesenteric vein ascends in the retroperitoneal plane over the psoas muscle and continues posterior to the pancreas to join the splenic vein. During a col-ectomy, this vein is often mobilized independently and ligated at the inferior edge of the pancreas.Colon Lymphatic Drainage. The lymphatic drainage of the colon originates in a network of lymphatics in


Surgery_Schwartz

Surgery_Schwartz. this vein is often mobilized independently and ligated at the inferior edge of the pancreas.Colon Lymphatic Drainage. The lymphatic drainage of the colon originates in a network of lymphatics in the muscula-ris mucosa. Lymphatic vessels and lymph nodes follow the regional arteries. Lymph nodes are found on the bowel wall (epicolic), along the inner margin of the bowel adjacent to the arterial arcades (paracolic), around the named mesenteric ves-sels (intermediate), and at the origin of the superior and inferior mesenteric arteries (main).Colon Nerve Supply. The colon is innervated by both sympathetic (inhibitory) and parasympathetic (stimulatory) nerves, which parallel the course of the arteries. Sympathetic nerves arise from T6–T12 and L1–L3. The parasympathetic innervation to the right and transverse colon is from the vagus nerve; the parasympathetic nerves to the left colon arise from sacral nerves S2–S4 to form the nervi erigentes.Anorectal Landmarks. The rectum is approximately


Surgery_Schwartz

Surgery_Schwartz. and transverse colon is from the vagus nerve; the parasympathetic nerves to the left colon arise from sacral nerves S2–S4 to form the nervi erigentes.Anorectal Landmarks. The rectum is approximately 12 to 15 cm in length. Three distinct submucosal folds, the valves of Houston, extend into the rectal lumen. Posteriorly, the presecral fascia separates the rectum from the presacral venous plexus and the pelvic nerves. At S4, the rectosacral fascia (Waldeyer’s fascia) extends anteriorly and caudally and attaches to the fas-cia propria at the anorectal junction. Anteriorly, Denonvilliers’ fascia separates the rectum from the prostate and seminal ves-icles in men and from the vagina in women. The lateral liga-ments support the lower rectum.The anatomic anal canal extends from the dentate or pectinate line to the anal verge. The dentate or pectinate line marks the transition point between columnar rectal mucosa and squamous anoderm. The anal transition zone includes mucosa proximal to the


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Surgery_Schwartz. line to the anal verge. The dentate or pectinate line marks the transition point between columnar rectal mucosa and squamous anoderm. The anal transition zone includes mucosa proximal to the dentate line that shares histologic characteris-tics of columnar, cuboidal, and squamous epithelium. Although the anal transition zone was long thought to extend only 1 to 2 cm proximal to the dentate line, it is known that the proxi-mal extent of this zone is highly variable and can be as far as 15 cm proximal to the dentate line. The dentate line is sur-rounded by longitudinal mucosal folds, known as the columns of Morgagni, into which the anal crypts empty. These crypts are the source of cryptoglandular abscesses (Fig. 29-3). In contrast to the anatomic anal canal, the surgical anal canal begins at the Middlecolic a.Rightcolic a.Leftcolic a.Ileocolic a.Superiormesenteric a.Superiorrectal a.Sigmoidal a.Inferiormesenteric a.Figure 29-1. Arterial blood supply to the colon. a. =


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Surgery_Schwartz. canal begins at the Middlecolic a.Rightcolic a.Leftcolic a.Ileocolic a.Superiormesenteric a.Superiorrectal a.Sigmoidal a.Inferiormesenteric a.Figure 29-1. Arterial blood supply to the colon. a. = artery.Inferiormesenteric v.Middlecolic v.Rightcolic v.Superiormesenteric v.Portal v.Leftcolic v.Sigmoidal v.Superiorrectal v.Ileocolic v.Figure 29-2. Venous drainage of the colon. v. = vein. (Reproduced with permission from Bell RH, Rikkers LF, Mulholland M: Diges-tive Tract Surgery: A Text and Atlas. Philadelphia, PA: Lippincott Williams & Wilkins; 1996.)Brunicardi_Ch29_p1259-p1330.indd 126123/02/19 2:28 PM 1262SPECIFIC CONSIDERATIONSPART IIanorectal junction and terminates at the anal verge. The surgical anal canal measures 2 to 4 cm in length and is generally longer in men than in women. It begins at the anorectal junction and terminates at the anal verge.In the distal rectum, the inner smooth muscle is thickened and comprises the internal anal sphincter that is surrounded by the


Surgery_Schwartz

Surgery_Schwartz. It begins at the anorectal junction and terminates at the anal verge.In the distal rectum, the inner smooth muscle is thickened and comprises the internal anal sphincter that is surrounded by the subcutaneous, superficial, and deep external sphincter. The deep external anal sphincter is an extension of the puborectalis muscle. The puborectalis, iliococcygeus, and pubococcygeus muscles form the levator ani muscle of the pelvic floor (Fig. 29-4).Anorectal Vascular Supply. The superior rectal artery arises from the terminal branch of the inferior mesenteric artery and supplies the upper rectum. The middle rectal artery arises from the internal iliac; the presence and size of these arteries are highly variable. The inferior rectal artery arises from the inter-nal pudendal artery, which is a branch of the internal iliac artery. A rich network of collaterals connects the terminal arterioles of each of these arteries, thus making the rectum relatively resis-tant to ischemia (Fig. 29-5).The


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Surgery_Schwartz. branch of the internal iliac artery. A rich network of collaterals connects the terminal arterioles of each of these arteries, thus making the rectum relatively resis-tant to ischemia (Fig. 29-5).The venous drainage of the rectum parallels the arterial supply. The superior rectal vein drains into the portal system via the inferior mesenteric vein. The middle rectal vein drains into the internal iliac vein. The inferior rectal vein drains into the internal pudendal vein, and subsequently into the internal iliac vein. A submucosal plexus deep to the columns of Morgagni forms the hemorrhoidal plexus and drains into all three veins.Anorectal Lymphatic Drainage. Lymphatic drainage of the rectum parallels the vascular supply. Lymphatic channels in the upper and middle rectum drain superiorly into the inferior mes-enteric lymph nodes. Lymphatic channels in the lower rectum drain both superiorly into the inferior mesenteric lymph nodes and laterally into the internal iliac lymph nodes. The


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Surgery_Schwartz. into the inferior mes-enteric lymph nodes. Lymphatic channels in the lower rectum drain both superiorly into the inferior mesenteric lymph nodes and laterally into the internal iliac lymph nodes. The anal canal has a more complex pattern of lymphatic drainage. Proximal to the dentate line, lymph drains into both the inferior mesen-teric lymph nodes and the internal iliac lymph nodes. Distal to the dentate line, lymph primarily drains into the inguinal lymph nodes, but can also drain into the inferior mesenteric lymph nodes and internal iliac lymph nodes.AnalcanalColumn of MorgagniDentate lineAnal cryptAnal glandAnodermTransitionzoneFigure 29-3. The lining of the anal canal. (Reproduced with permission from Goldberg SM, Gordon PH, Nivatvongs S: Essentials of Anorectal Surgery. Philadelphia, PA: JB Lippincott Company; 1980.)Deep external sphincterand puborectalis mm.Conjoinedlongitudinal m.Superficial externalsphincter m.Subcutaneous externalsphincter m.Valve of HoustonInternal


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Surgery_Schwartz. PA: JB Lippincott Company; 1980.)Deep external sphincterand puborectalis mm.Conjoinedlongitudinal m.Superficial externalsphincter m.Subcutaneous externalsphincter m.Valve of HoustonInternal rectalplexusMuscularis submucosa ani m.Transverse septumof ischiorectal fossaExternal rectalplexusInternalsphincter m.Figure 29-4. The distal rectum and anal canal. m. = muscle.Brunicardi_Ch29_p1259-p1330.indd 126223/02/19 2:28 PM 1263COLON, RECTUM, AND ANUSCHAPTER 29Anorectal Nerve Supply. Both sympathetic and parasym-pathetic nerves innervate the anorectum. Sympathetic nerve fibers are derived from L1–L3 and join the preaortic plexus. The preaortic nerve fibers then extend below the aorta to form the hypogastric plexus, which subsequently joins the para-sympathetic fibers to form the pelvic plexus. Parasympathetic nerve fibers are known as the nervi erigentes and originate from S2–S4. These fibers join the sympathetic fibers to form the pel-vic plexus. Sympathetic and parasympathetic fibers


Surgery_Schwartz

Surgery_Schwartz. Parasympathetic nerve fibers are known as the nervi erigentes and originate from S2–S4. These fibers join the sympathetic fibers to form the pel-vic plexus. Sympathetic and parasympathetic fibers then supply the anorectum and adjacent urogenital organs.The internal anal sphincter is innervated by sympathetic and parasympathetic nerve fibers; both types of fibers inhibit sphincter contraction. The external anal sphincter and puborec-talis muscles are innervated by the inferior rectal branch of the internal pudendal nerve. The levator ani receives innervation from both the internal pudendal nerve and direct branches of S3 to S5. Sensory innervation to the anal canal is provided by the inferior rectal branch of the pudendal nerve. While the rec-tum is relatively insensate, the anal canal below the dentate line receives somatic innervation.Congenital AnomaliesPerturbation of the embryologic development of the midgut and hindgut may result in anatomic abnormalities of the colon, rec-tum,


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Surgery_Schwartz. the dentate line receives somatic innervation.Congenital AnomaliesPerturbation of the embryologic development of the midgut and hindgut may result in anatomic abnormalities of the colon, rec-tum, and anus. Failure of the midgut to rotate and return to the abdominal cavity during the tenth week of gestation results in varying degrees of intestinal malrotation and colonic nonfix-ation. Failure of canalization of the primitive gut can result in colonic duplication. Incomplete descent of the urogenital sep-tum may result in imperforate anus and associated fistulas to the genitourinary tract. Many infants with congenital anomalies of the hindgut have associated abnormalities in the genitourinary tract.NORMAL PHYSIOLOGYFluid and Electrolyte ExchangesWater, Sodium, Potassium, Chloride, Bicarbonate, and Ammonia. The colon is a major site for water absorption and electrolyte exchange. Under normal circumstances, approxi-mately 90% of the water contained in ileal fluid is absorbed in the colon


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Surgery_Schwartz. and Ammonia. The colon is a major site for water absorption and electrolyte exchange. Under normal circumstances, approxi-mately 90% of the water contained in ileal fluid is absorbed in the colon (1000–2000 mL/d), but up to 5000 mL of fluid can be absorbed daily. Sodium is absorbed actively via sodiumpotassium (Na+/K+) ATPase. The colon can absorb up to 400 mEq of sodium per day. Water accompanies the transported sodium and is absorbed passively along an osmotic gradient. Potassium is actively secreted into the colonic lumen and absorbed by passive diffusion. Chloride is absorbed actively via a chloride-bicarbonate exchange.Bacterial degradation of protein and urea produces ammo-nia. Ammonia is subsequently absorbed and transported to the liver. Absorption of ammonia depends in part on intraluminal pH. A decrease in colonic bacteria (e.g., due to broad-spectrum antibiotic use) and/or a decrease in intraluminal pH (e.g., due to lactulose administration) will decrease ammonia


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Surgery_Schwartz. part on intraluminal pH. A decrease in colonic bacteria (e.g., due to broad-spectrum antibiotic use) and/or a decrease in intraluminal pH (e.g., due to lactulose administration) will decrease ammonia absorption.Short-Chain Fatty AcidsShort-chain fatty acids (acetate, butyrate, and propionate) are produced by bacterial fermentation of dietary carbohydrates. Short-chain fatty acids are an important source of energy for the colonic mucosa, and metabolism by colonocytes provides energy for processes such as active transport of sodium. Lack of a dietary source for production of short-chain fatty acids, or diversion of the fecal stream by an ileostomy or colostomy, may result in mucosal atrophy and inflammation, the latter termed “diversion colitis.”Colonic Microflora and Intestinal GasApproximately 30% of fecal dry weight is composed of bacteria (1011–1012 bacteria/g of feces). Anaerobes are the predominant class of microorganism, and Bacteroides species are the most common (1011–1012


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Surgery_Schwartz. 30% of fecal dry weight is composed of bacteria (1011–1012 bacteria/g of feces). Anaerobes are the predominant class of microorganism, and Bacteroides species are the most common (1011–1012 organisms/mL). Escherichia coli are the most numerous aerobes (108–1010 organisms/mL). Endogenous microflora are crucial for the breakdown of carbohydrates and proteins in the colon and participate in the metabolism of biliru-bin, bile acids, estrogen, and cholesterol. Colonic bacteria also are necessary for production of vitamin K. Endogenous bacteria also are thought to suppress the emergence of pathogenic micro-organisms, such as Clostridium difficile, a phenomenon termed “colonization resistance.” However, the high bacterial load of the large intestine may contribute to sepsis in critically ill patients and may contribute to intra-abdominal sepsis, abscess, and wound infection following colectomy. Burgeoning research on the human gut microbiome offers new concepts of bacterial community


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Surgery_Schwartz. ill patients and may contribute to intra-abdominal sepsis, abscess, and wound infection following colectomy. Burgeoning research on the human gut microbiome offers new concepts of bacterial community structure and its impact on gastrointestinal disease. Use of 16S ribosomal RNA, universally present in bacteria, allows for a more complete understanding of colonic samples, without the use of stool cultures.Intestinal gas arises from swallowed air, diffusion from the blood, and intraluminal production. Nitrogen, oxygen, car-bon dioxide, hydrogen, and methane are the major components of intestinal gas. Nitrogen and oxygen are largely derived from swallowed air. Carbon dioxide is produced by the reaction of bicarbonate and hydrogen ions and by the digestion of triglyc-erides to fatty acids. Hydrogen and methane are produced by colonic bacteria. The production of methane is highly variable. The gastrointestinal tract usually contains between 100 and 200 mL of gas, and 400 to 1200 mL/d are


Surgery_Schwartz

Surgery_Schwartz. and methane are produced by colonic bacteria. The production of methane is highly variable. The gastrointestinal tract usually contains between 100 and 200 mL of gas, and 400 to 1200 mL/d are released as flatus, depending on the type of food ingested.Motility, Defecation, and ContinenceMotility. Unlike the small intestine, the large intestine does not demonstrate cyclic motor activity characteristic of the migra-tory motor complex. Instead, the colon displays intermittent Internaliliac arterySuperiorrectal arteryMiddlerectal arteryInferiorrectal arteryInferiormesenteric arteryMiddlesacral arteryLevatorani muscleFigure 29-5. Arterial supply to the rectum and anal canal.Brunicardi_Ch29_p1259-p1330.indd 126323/02/19 2:28 PM 1264SPECIFIC CONSIDERATIONSPART IIcontractions of either low or high amplitude. Low-amplitude, short-duration contractions occur in bursts and appear to move the colonic contents both antegrade and retrograde. It is thought that these bursts of motor activity


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Surgery_Schwartz. or high amplitude. Low-amplitude, short-duration contractions occur in bursts and appear to move the colonic contents both antegrade and retrograde. It is thought that these bursts of motor activity delay colonic transit and thus increase the time available for absorption of water and exchange of electrolytes. High-amplitude, prolonged duration, propagated contractions (HAPCs) occur in a more coordinated fashion and create “mass movements,” four to ten times per day, mostly after meals and awakening. Bursts of “rectal motor complexes” also have been described. In general, cholinergic activation increases colonic motility.Defecation. Defecation is a complex, coordinated mechanism involving colonic mass movement, increased intra-abdominal and rectal pressure, and relaxation of the pelvic floor. Disten-tion of the rectum causes a reflex relaxation of the internal anal sphincter (the rectoanal inhibitory reflex) that allows the contents to make contact with the anal canal. This “sampling


Surgery_Schwartz

Surgery_Schwartz. Disten-tion of the rectum causes a reflex relaxation of the internal anal sphincter (the rectoanal inhibitory reflex) that allows the contents to make contact with the anal canal. This “sampling reflex” allows the sensory epithelium to distinguish solid stool from liquid stool and gas. If defecation does not occur, the rec-tum relaxes and the urge to defecate passes (accommodation response). Defecation proceeds by coordinating increasing intra-abdominal pressure via a Valsalva maneuver with rectal contraction, relaxation of the puborectalis muscle, and opening of the anal canal.Continence. The maintenance of fecal continence is at least as complex as the mechanism of defecation. Continence requires adequate rectal wall compliance to accommodate the fecal bolus, appropriate neurogenic control of the pelvic floor and sphincter mechanism, and functional internal and exter-nal sphincter muscles. At rest, the puborectalis muscle creates a “sling” around the distal rectum, forming a


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Surgery_Schwartz. control of the pelvic floor and sphincter mechanism, and functional internal and exter-nal sphincter muscles. At rest, the puborectalis muscle creates a “sling” around the distal rectum, forming a relatively acute angle that distributes intra-abdominal forces onto the pelvic floor. With defecation, this angle straightens, allowing down-ward force to be applied along the axis of the rectum and anal canal. The internal and external sphincters are tonically active at rest. The internal sphincter is responsible for most of the rest-ing, involuntary sphincter tone (resting pressure). The external sphincter is responsible for most of the voluntary sphincter tone (squeeze pressure). Branches of the pudendal nerve innervate both the internal and external sphincter. The hemorrhoidal cush-ions may contribute to continence by mechanically blocking the anal canal. Finally, liquid stools exacerbate abnormalities with these anatomic and physiologic mechanisms, so a formed stool contributes to


Surgery_Schwartz

Surgery_Schwartz. may contribute to continence by mechanically blocking the anal canal. Finally, liquid stools exacerbate abnormalities with these anatomic and physiologic mechanisms, so a formed stool contributes to maintaining continence. Thus, impaired con-tinence may result from poor rectal compliance, injury to the internal and/or external sphincter or puborectalis, or neuropathy.CLINICAL EVALUATIONClinical AssessmentObtaining a complete history and performing a physical exami-nation are the starting points for evaluating any patient with suspected disease of the colon, rectum, or anus. Special atten-tion should be paid to the patient’s past medical and surgical history to detect underlying conditions that might contribute to a gastrointestinal problem. If patients have had prior intes-tinal surgery, it is essential that one understand the resultant gastrointestinal anatomy. A history of anorectal surgery may be critical for patients with either abdominal or anorectal com-plaints. The obstetrical


Surgery_Schwartz

Surgery_Schwartz. it is essential that one understand the resultant gastrointestinal anatomy. A history of anorectal surgery may be critical for patients with either abdominal or anorectal com-plaints. The obstetrical history in women is essential to detect occult pelvic floor and/or anal sphincter damage. Identifying a family history of colorectal disease, especially inflammatory bowel disease, polyps, and colorectal cancer, is crucial. In addi-tion to a family history of colorectal disease, a history of other malignancies may suggest the presence of a genetic syndrome. Medication use must be detailed as many drugs cause gastroin-testinal symptoms. Before recommending operative interven-tion, the adequacy of medical treatment must be ascertained. In addition to examining the abdomen, visual inspection of the anus and perineum and careful digital rectal exam are essential.EndoscopyAnoscopy. The anoscope is a useful instrument for examina-tion of the anal canal. Anoscopes are made in a variety of sizes


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Surgery_Schwartz. the anus and perineum and careful digital rectal exam are essential.EndoscopyAnoscopy. The anoscope is a useful instrument for examina-tion of the anal canal. Anoscopes are made in a variety of sizes and measure approximately 8 cm in length. A larger anoscope provides better exposure for anal procedures such as rubber band ligation or sclerotherapy of hemorrhoids. The anoscope, with obturator in place, should be adequately lubricated and gently inserted into the anal canal. The obturator is withdrawn, inspec-tion of the visualized anal canal is done, and the anoscope should then be withdrawn. It is rotated 90° and reinserted to allow visual-ization of all four quadrants of the canal. If the patient complains of severe perianal pain and cannot tolerate a digital rectal exami-nation, anoscopy should not be attempted without anesthesia.Proctoscopy. The rigid proctoscope is useful for examination of the rectum and distal sigmoid colon and is occasionally used therapeutically. The standard


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Surgery_Schwartz. should not be attempted without anesthesia.Proctoscopy. The rigid proctoscope is useful for examination of the rectum and distal sigmoid colon and is occasionally used therapeutically. The standard proctoscope is 25 cm in length and available in various diameters. Most often, a 15or 19-mm diameter proctoscope is used for diagnostic examinations. A smaller “pediatric” proctoscope (11-mm diameter) is better tol-erated by patients with anal stricture. Suction is necessary for an adequate proctoscopic examination. An operating platform for transanal surgery known as transanal endoscopic microsurgery (TEM) has a much wider diameter and can be used for exci-sions of large polyps and tumors. Transanal minimally invasive surgery (TAMIS) can achieve similar resections to TEM, but it does not utilize a proctoscope and instead depends on insuf-flation to create a working space in the rectum while utilizing a circular wound protector to open the anus.Flexible Sigmoidoscopy and Colonoscopy. Video


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Surgery_Schwartz. a proctoscope and instead depends on insuf-flation to create a working space in the rectum while utilizing a circular wound protector to open the anus.Flexible Sigmoidoscopy and Colonoscopy. Video or fiber-optic flexible sigmoidoscopy and colonoscopy provide excellent visualization of the colon and rectum. Sigmoidoscopes measure 60 cm in length. Full depth of insertion may allow visualiza-tion as high as the splenic flexure, although the mobility and redundancy of the sigmoid colon often limit the extent of the examination. Partial preparation with enemas is usually adequate for sigmoidoscopy, and most patients can tolerate this proce-dure without sedation. Colonoscopes measure 100 to 160 cm in length and are capable of examining the entire colon and terminal ileum. A complete oral bowel preparation is usually necessary for colonoscopy, and the duration and discomfort of the procedure usually require conscious sedation. Both sigmoid-oscopy and colonoscopy can be used diagnostically


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Surgery_Schwartz. preparation is usually necessary for colonoscopy, and the duration and discomfort of the procedure usually require conscious sedation. Both sigmoid-oscopy and colonoscopy can be used diagnostically and thera-peutically. Electrocautery should generally not be used in the absence of a complete bowel preparation because of the risk of explosion of intestinal methane or hydrogen gases. Diagnostic colonoscopes possess a single channel through which instru-ments such as snares, biopsy forceps, or electrocautery can be passed; this channel also provides suction and irrigation capa-bility. Therapeutic colonoscopes possess two channels to allow simultaneous suction/irrigation and the use of snares, biopsy forceps, or electrocautery.Brunicardi_Ch29_p1259-p1330.indd 126423/02/19 2:28 PM 1265COLON, RECTUM, AND ANUSCHAPTER 29Capsule Endoscopy. Capsule endoscopy uses a small ingest-ible camera. After swallowing the camera, images of the mucosa of the gastrointestinal tract are captured,


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Surgery_Schwartz. RECTUM, AND ANUSCHAPTER 29Capsule Endoscopy. Capsule endoscopy uses a small ingest-ible camera. After swallowing the camera, images of the mucosa of the gastrointestinal tract are captured, transmitted by radiofre-quency to a belt-held receiver, and then downloaded to a com-puter for viewing and analysis. Capsule endoscopy largely has been used to detect small bowel lesions. Recent advances in the development of maneuverable capsules may improve the sensi-tivity of this procedure.1 Finally, concern over the possibility of an acute obstruction has led to the development of a dissolvable capsule that can detect obstruction lesions. Although this tech-nology is promising, the ultimate utility of capsule endoscopy remains unknown.ImagingPlain X-Rays and Contrast Studies. Despite advanced radio-logic techniques, plain X-rays and contrast studies continue to play an important role in the evaluation of patients with sus-pected colon and rectal diseases. Plain X-rays of the abdomen (supine,


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Surgery_Schwartz. techniques, plain X-rays and contrast studies continue to play an important role in the evaluation of patients with sus-pected colon and rectal diseases. Plain X-rays of the abdomen (supine, upright, and diaphragmatic views) are useful for detect-ing free intra-abdominal air, bowel gas patterns suggestive of small or large bowel obstruction, and volvulus. Contrast studies are useful for evaluating obstructive symptoms, delineating fis-tulous tracts, and diagnosing small perforations or anastomotic leaks. Although Gastrografin cannot provide the mucosal detail provided by barium, this water-soluble contrast agent is rec-ommended if perforation or leak is suspected. Double-contrast barium enema (use of barium followed by the insufflation of air into the colon) has been reported to be 70% to 90% sensitive for the detection of mass lesions greater than 1 cm in diameter. Detection of small lesions can be extremely difficult, especially in a patient with extensive diverticulosis. For this


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Surgery_Schwartz. 90% sensitive for the detection of mass lesions greater than 1 cm in diameter. Detection of small lesions can be extremely difficult, especially in a patient with extensive diverticulosis. For this reason, a colo-noscopy is preferred for evaluating nonobstructing mass lesions in the colon. Double-contrast barium enema has been used as a back-up examination if colonoscopy is incomplete.Computed Tomography. Computed tomography (CT) com-monly is employed in the evaluation of patients with abdominal complaints. Its utility is primarily in the detection of extralu-minal disease, such as intra-abdominal abscesses and pericolic inflammation, and in staging colorectal carcinoma because of its sensitivity in detection of hepatic metastases.Extravasation of oral or rectal contrast may also confirm the diagnosis of perforation or anastomotic leak. Nonspecific findings such as bowel wall thickening or mesenteric strand-ing may suggest inflammatory bowel disease, enteritis/colitis, or ischemia. A


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Surgery_Schwartz. the diagnosis of perforation or anastomotic leak. Nonspecific findings such as bowel wall thickening or mesenteric strand-ing may suggest inflammatory bowel disease, enteritis/colitis, or ischemia. A standard CT scan is relatively insensitive for the detection of intraluminal lesions.Computed Tomography Colonography. CT colonography (virtual colonoscopy) is a radiologic technique that is designed to overcome some of the limitations of traditional CT scan-ning. This technology uses helical CT and three-dimensional reconstruction to detect intraluminal colonic lesions. Oral bowel preparation, oral and rectal contrast, and colon insufflation have been used to maximize sensitivity. Experience with this technol-ogy has shown a sensitivity and specificity for detecting 1 cm or larger polyps of 85% to 90% in most studies, making it compa-rable to traditional colonoscopy. Although this technology has yet to be widely adopted, it remains an alternative to traditional colonoscopy for select


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Surgery_Schwartz. of 85% to 90% in most studies, making it compa-rable to traditional colonoscopy. Although this technology has yet to be widely adopted, it remains an alternative to traditional colonoscopy for select patients.2Magnetic Resonance Imaging. The main use of magnetic resonance imaging (MRI) in colorectal disorders is in evaluation of pelvic lesions. MRI is more sensitive than CT for detecting bony involvement or pelvic sidewall extension of rectal tumors. MRI accurately determines the extent of spread of rectal cancer into the adjacent mesorectum and can reliably predict diffi-culty achieving radial margin clearance of a rectal cancer by surgery alone. When the radial margin is threatened, neoadju-vant chemoradiation is indicated. MRI also can be helpful in the detection and delineation of complex fistulas in ano. The use of an endorectal coil may increase sensitivity.Positron Emission Tomography. Positron emission tomog-raphy (PET) is used for imaging tissues with high levels of anaerobic


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Surgery_Schwartz. fistulas in ano. The use of an endorectal coil may increase sensitivity.Positron Emission Tomography. Positron emission tomog-raphy (PET) is used for imaging tissues with high levels of anaerobic glycolysis, such as malignant tumors. 13F-fluorode-oxyglucose (FDG) is injected as a tracer; metabolism of this molecule then results in positron emission. PET has been used as an adjunct to CT in the staging of colorectal cancer and may prove useful in discriminating recurrent cancer from fibrosis. By combining PET and CT technology (PET/CT), anatomic correlation between regions of high isotope accumulation (“hot spots”) on PET and abnormalities on CT can be determined. PET/CT increasingly is used to diagnose recurrent and/or meta-static colorectal cancer. However, the efficacy and utility of this technology remains unproven.Scintigraphy to Assess Gastrointestinal Bleeding. Scin-tigraphy to assess for gastrointestinal bleeding (technetium-99-tagged red blood cell [RBC] scan; “tagged RBC


Surgery_Schwartz

Surgery_Schwartz. this technology remains unproven.Scintigraphy to Assess Gastrointestinal Bleeding. Scin-tigraphy to assess for gastrointestinal bleeding (technetium-99-tagged red blood cell [RBC] scan; “tagged RBC scan”) is a nuclear medicine test that uses 99mTc-erythrocytes and dynamic images to localize a bleeding source. Patients must be actively bleeding at the time of imaging, and a normal distribution of 99mTc-erythrocytes in vasculature, liver, spleen, penile circula-tion with mild uptake in kidneys and bladder can interfere with localization in bowel segments near those structures. Patients must be stable enough to tolerate imaging intervals of up to 4 hours, but slow bleeding at a rate of 0.05 to 0.2 mL/minute can be detected.3Single Photon Emission Computed Tomography (SPECT/CT). Radiolabeled erythrocytes are also used for SPECT/CT, but cross-sectional images provide a more specific localization of the bleeding source, which can be very helpful for surgical planning, especially if direct


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Surgery_Schwartz. erythrocytes are also used for SPECT/CT, but cross-sectional images provide a more specific localization of the bleeding source, which can be very helpful for surgical planning, especially if direct visualization via endoscopy has not been successful.4Angiography. Angiography is occasionally used for the detec-tion of bleeding within the colon or small bowel. To visual-ize hemorrhage angiographically, bleeding must be relatively brisk (approximately 0.5 to 1.0 mL per minute). If extravasa-tion of contrast is identified, infusion of vasopressin or angio-graphic embolization can be therapeutic. If surgical resection is required, the angiographic catheter can be left in place to assist with identification of the bleeding site intraoperatively.CT and magnetic resonance angiography are also useful for assessing patency of visceral vessels. This technique uses three-dimensional reconstruction to detect vascular lesions. If an abnormality is found, more traditional techniques (angiography,


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Surgery_Schwartz. for assessing patency of visceral vessels. This technique uses three-dimensional reconstruction to detect vascular lesions. If an abnormality is found, more traditional techniques (angiography, surgery) may then be used to further define and/or correct the problem.Endorectal and Endoanal Ultrasound. Endorectal ultra-sound is primarily used to evaluate the depth of invasion of neoplastic lesions in the rectum. The normal rectal wall appears as a five-layer structure (Fig. 29-6). Ultrasound can reliably dif-ferentiate most benign polyps from invasive tumors based on the integrity of the submucosal layer. Ultrasound can also dif-ferentiate superficial T1-T2 from deeper T3-T4 tumors. Overall, Brunicardi_Ch29_p1259-p1330.indd 126523/02/19 2:28 PM 1266SPECIFIC CONSIDERATIONSPART IIthe accuracy of ultrasound in detecting depth of mural invasion ranges between 81% and 94%. This modality also can detect enlarged perirectal lymph nodes, which may suggest nodal metastases; accuracy of


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Surgery_Schwartz. accuracy of ultrasound in detecting depth of mural invasion ranges between 81% and 94%. This modality also can detect enlarged perirectal lymph nodes, which may suggest nodal metastases; accuracy of detection of pathologically positive lymph nodes is 58% to 83%. Ultrasound may also prove useful for early detection of local recurrence after surgery.5Endoanal ultrasound is used to evaluate the layers of the anal canal. Internal anal sphincter, external anal sphincter, and puborectalis muscle can be differentiated. Endoanal ultrasound is particularly useful for detecting sphincter defects and for out-lining complex anal fistulas. MRI has also proven to be helpful in delineating the anatomy of fistulae, especially in complex cases. This modality increasingly is utilized for the evaluation of anal fistulae.Physiologic and Pelvic Floor InvestigationsAnorectal physiologic testing uses a variety of techniques to investigate the function of the pelvic floor. These techniques are useful in the


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Surgery_Schwartz. anal fistulae.Physiologic and Pelvic Floor InvestigationsAnorectal physiologic testing uses a variety of techniques to investigate the function of the pelvic floor. These techniques are useful in the evaluation of patients with incontinence, constipa-tion, rectal prolapse, obstructed defecation, and other functional disorders of the pelvic floor.Manometry. Anorectal manometry is performed by placing a pressure-sensitive catheter in the lower rectum. The catheter is then withdrawn through the anal canal and pressures recorded. A balloon attached to the tip of the catheter also can be used to test anorectal sensation. The resting pressure in the anal canal reflects the function of the internal anal sphincter (nor-mal 40–80 mmHg), whereas the squeeze pressure, defined as the maximum voluntary contraction pressure minus the resting pressure, reflects function of the external anal sphincter (normal 40–80 mmHg above resting pressure). The high-pressure zone estimates the length of the anal


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Surgery_Schwartz. contraction pressure minus the resting pressure, reflects function of the external anal sphincter (normal 40–80 mmHg above resting pressure). The high-pressure zone estimates the length of the anal canal (normal 2.0–4.0 cm). The rectoanal inhibitory reflex can be detected by inflating a balloon in the distal rectum; absence of this reflex is characteristic of Hirschsprung’s disease.Neurophysiology. Neurophysiologic testing assesses func-tion of the pudendal nerves and recruitment of puborectalis muscle fibers. Pudendal nerve terminal motor latency mea-sures the speed of transmission of a nerve impulse through the distal pudendal nerve fibers (normal 1.8–2.2 ms); prolonged latency suggests the presence of neuropathy. Electromyographic (EMG) recruitment assesses the contraction and relaxation of the puborectalis muscle during attempted defecation. Normally, recruitment increases when a patient is instructed to “squeeze” and decreases when a patient is instructed to “push.”


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Surgery_Schwartz. and relaxation of the puborectalis muscle during attempted defecation. Normally, recruitment increases when a patient is instructed to “squeeze” and decreases when a patient is instructed to “push.” Inappro-priate recruitment is an indication of paradoxical contraction (nonrelaxation of the puborectalis). Needle EMG has been used to map both the pudendal nerves and the anatomy of the internal and external sphincters. However, this examination is painful and poorly tolerated by most patients. Needle EMG has largely been replaced by pudendal nerve motor latency testing to assess pudendal nerve function and endoanal ultrasound to map the sphincters.Rectal Evacuation Studies. Rectal evacuation studies include the balloon expulsion test and video defecography. Balloon expulsion assesses a patient’s ability to expel an intrarectal bal-loon. Video defecography provides a more detailed assessment of defecation. In this test, barium paste is placed in the rectum, and defecation is then


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Surgery_Schwartz. a patient’s ability to expel an intrarectal bal-loon. Video defecography provides a more detailed assessment of defecation. In this test, barium paste is placed in the rectum, and defecation is then recorded fluoroscopically. Defecography is used to help diagnose obstructed defecation from nonrelax-ation of the puborectalis muscle or anal sphincter dyssynergy, increased perineal descent, rectal prolapse and intussusception, rectocele, and enterocele. The addition of vaginal contrast and intraperitoneal contrast is useful in delineating complex disor-ders of the pelvic floor.Laboratory StudiesFecal Occult Blood Testing and Fecal Immunohistochemical Testing. Fecal occult blood testing (FOBT) has been used as a screening test for colonic neoplasms in asymptomatic, average-risk individuals. The efficacy of this test is based on serial test-ing because the majority of colorectal malignancies will bleed intermittently. FOBT has been a nonspecific test for peroxidase contained in


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Surgery_Schwartz. The efficacy of this test is based on serial test-ing because the majority of colorectal malignancies will bleed intermittently. FOBT has been a nonspecific test for peroxidase contained in hemoglobin; consequently, occult bleeding from any gastrointestinal source will produce a positive result. Simi-larly, many foods (red meat, some fruits and vegetables, and vitamin C) will produce a false-positive result. Increased speci-ficity for cancer detection is possible by using fecal immuno-chemical test (FIT). Reported sensitivity of 79% and specificity Mucosal surfaceMucosa/Muscularis mucosaSubmucosaMuscularis propriaSerosa/Perirectal fatBAFigure 29-6. A. Schematic of the layers of the rectal wall observed on endorectal ultrasonography. B. Normal endorectal ultrasonog-raphy. (A. Used with permission from Charles O. Finne III, MD, Minneapolis, MN.)Brunicardi_Ch29_p1259-p1330.indd 126623/02/19 2:28 PM 1267COLON, RECTUM, AND ANUSCHAPTER 29of 94% has led to widespread use of FIT in


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Surgery_Schwartz. permission from Charles O. Finne III, MD, Minneapolis, MN.)Brunicardi_Ch29_p1259-p1330.indd 126623/02/19 2:28 PM 1267COLON, RECTUM, AND ANUSCHAPTER 29of 94% has led to widespread use of FIT in current population-based screening approaches. These tests rely on monoclonal or polyclonal antibodies to react with the intact globin portion of human hemoglobin and are more specific for identifying occult bleeding from the colon or rectum. Any positive FOBT or FIT mandates further investigation, usually by colonoscopy.6 More recently, stool DNA testing has been proposed for early detec-tion of colorectal cancer.7Stool Studies. Stool studies are often helpful in evaluating the etiology of diarrhea. Wet-mount examination reveals the pres-ence of fecal leukocytes, which may suggest colonic inflamma-tion or the presence of an invasive organism such as invasive E coli or Shigella species. Stool cultures can detect pathogenic bacteria, ova, and/or parasites. C difficile colitis is diagnosed by


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Surgery_Schwartz. or the presence of an invasive organism such as invasive E coli or Shigella species. Stool cultures can detect pathogenic bacteria, ova, and/or parasites. C difficile colitis is diagnosed by detecting bacterial toxin in the stool. Steatorrhea may be diag-nosed by adding Sudan red stain to a stool sample.Tumor Markers. Carcinoembryonic antigen (CEA) may be elevated in 60% to 90% of patients with colorectal cancer. Preoperative CEA level has recently been suggested to be a prognostic indicator.8 Despite this, CEA is not an effective screening tool for this malignancy. Many practitioners follow serial CEA levels after curative-intent surgery in order to detect early recurrence of colorectal cancer. However, this tumor marker is nonspecific, and no survival benefit associated with its serial measurements has yet been proven. It is also important to note that CEA may be mildly elevated in patients who smoke tobacco. Other biochemical markers (ornithine decarboxylase, urokinase) have been


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Surgery_Schwartz. measurements has yet been proven. It is also important to note that CEA may be mildly elevated in patients who smoke tobacco. Other biochemical markers (ornithine decarboxylase, urokinase) have been proposed, but none has yet proven sensi-tive or specific for detection, staging, or predicting prognosis of colorectal carcinoma.Genetic Testing. Although familial colorectal cancer syn-dromes, such as familial adenomatous polyposis (FAP) and hereditary nonpolyposis colon cancer (HNPCC) are rare, infor-mation about the specific genetic abnormalities underlying these disorders has led to significant interest in the role of genetic testing for colorectal cancer.9Tests for mutations in the adenomatous polyposis coli (APC) gene responsible for FAP and in mismatch repair genes responsible for HNPCC are commercially available and extremely accurate in families with known mutations. However, in the absence of an identified mutation, a negative result is uninformative. For individuals from


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Surgery_Schwartz. HNPCC are commercially available and extremely accurate in families with known mutations. However, in the absence of an identified mutation, a negative result is uninformative. For individuals from high-risk families without an identified mutation, increased surveillance is recommended.10 Although many of these mutations are also present in sporadic colorectal cancer, the accuracy of genetic testing in average-risk individuals is considerably lower, and these tests are not recommended for screening. Due to the potential psychosocial implications of genetic testing, it is strongly recommended that professional genetic counselors be involved in the care of any patient considering these tests.Evaluation of Common SymptomsPain Abdominal Pain Abdominal pain is a nonspecific symptom with myriad causes. Abdominal pain related to the colon and rectum can result from obstruction (either inflammatory or neo-plastic), inflammation, perforation, or ischemia. Plain X-rays and judicious use of


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Surgery_Schwartz. causes. Abdominal pain related to the colon and rectum can result from obstruction (either inflammatory or neo-plastic), inflammation, perforation, or ischemia. Plain X-rays and judicious use of contrast studies and/or a CT scan can often confirm the diagnosis. Gentle retrograde contrast studies (Gastrografin enema) may be useful in delineating the degree of colonic obstruction. Sigmoidoscopy and/or colonoscopy performed by an experienced endoscopist can assist in the diagnosis of ischemic colitis, infectious colitis, and inflamma-tory bowel disease. However, if perforation or near complete obstruction is suspected, colonoscopy and/or sigmoidoscopy are generally contraindicated. Evaluation and treatment of abdomi-nal pain from a colorectal source should follow the usual surgi-cal principles of a thorough history and physical examination, appropriate diagnostic tests, resuscitation, and appropriately timed surgical intervention.Pelvic Pain Pelvic pain can originate from the distal


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Surgery_Schwartz. of a thorough history and physical examination, appropriate diagnostic tests, resuscitation, and appropriately timed surgical intervention.Pelvic Pain Pelvic pain can originate from the distal colon and rectum or from adjacent urogenital structures. Tenesmus may result from proctitis or from a rectal or retrorectal mass, or fecal impaction in a constipated patient. Cyclical pain associated with menses, especially when accompanied by rectal bleeding, suggests a diagnosis of endometriosis. Pelvic inflammatory dis-ease also can produce significant abdominal and pelvic pain. The extension of a peridiverticular abscess or periappendiceal abscess into the pelvis may also cause pain. CT scan and/or MRI may be useful in differentiating these diseases. Proctoscopy (if tolerated) also can be helpful. Occasionally, laparoscopy will yield a diagnosis, although with access to high-quality imaging, indications for diagnostic surgery should be rare.Anorectal Pain. Anorectal pain is most often


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Surgery_Schwartz. helpful. Occasionally, laparoscopy will yield a diagnosis, although with access to high-quality imaging, indications for diagnostic surgery should be rare.Anorectal Pain. Anorectal pain is most often secondary to an anal fissure, perirectal abscess and/or fistula, or a throm-bosed hemorrhoid. Physical examination can usually differenti-ate these conditions. Other, less common causes of anorectal pain include anal canal neoplasms, perianal skin infection, and dermatologic conditions. Proctalgia fugax results from levator spasm and may present without any other anorectal findings. Physical exam is critical in evaluating patients with anorec-tal pain. If a patient is too tender to examine in the office, an examination under anesthesia is necessary. MRI or other imag-ing studies may be helpful in select cases where the etiology of pain is elusive.Lower Gastrointestinal Bleeding. The first goal in evaluat-ing and treating a patient with gastrointestinal hemorrhage is adequate


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Surgery_Schwartz. may be helpful in select cases where the etiology of pain is elusive.Lower Gastrointestinal Bleeding. The first goal in evaluat-ing and treating a patient with gastrointestinal hemorrhage is adequate resuscitation. The second goal is to identify the source of hemorrhage. Because the most common source of gastroin-testinal hemorrhage is esophageal, gastric, or duodenal, naso-gastric aspiration should always be performed; return of bile suggests that the source of bleeding is distal to the ligament of Treitz. If aspiration reveals blood or nonbile secretions, or if symptoms suggest an upper intestinal source, esophagogastro-duodenoscopy should be performed. Anoscopy and/or limited proctoscopy can identify hemorrhoidal bleeding. A techne-tium-99 (99mTc)-tagged red blood cell (tagged RBC scan) scan is extremely sensitive and is able to detect as little as 0.1 mL/h of bleeding; however, localization is imprecise. If the 99mTc-tagged RBC scan is positive, angiography can then be both


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Surgery_Schwartz. scan) scan is extremely sensitive and is able to detect as little as 0.1 mL/h of bleeding; however, localization is imprecise. If the 99mTc-tagged RBC scan is positive, angiography can then be both diagnostic and potentially therapeutic. If the patient is hemodynamically stable, a rapid bowel preparation (over 4–6 hours) can be per-formed to allow colonoscopy. Colonoscopy may identify the cause of the bleeding, and cautery or injection/application of epinephrine into the bleeding site may be used to control hem-orrhage. A SPECT/CT may be helpful if other modalities have not achieved localization, particularly in distinguishing between small intestinal and colon sources. Colectomy may be required if bleeding persists despite interventions. Intraoperative colo-noscopy and/or enteroscopy may assist in localizing bleeding. If colectomy is required, a segmental resection is preferred if the bleeding source can be localized. “Blind” subtotal colectomy Brunicardi_Ch29_p1259-p1330.indd


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Surgery_Schwartz. may assist in localizing bleeding. If colectomy is required, a segmental resection is preferred if the bleeding source can be localized. “Blind” subtotal colectomy Brunicardi_Ch29_p1259-p1330.indd 126723/02/19 2:28 PM 1268SPECIFIC CONSIDERATIONSPART IIvery rarely may be required in a patient who is hemodynami-cally unstable with ongoing colonic hemorrhage of an unknown source. In this setting, just prior to proceeding with a “blind” subtotal colectomy, it is crucial to irrigate the rectosigmoid and reexamine the mucosa of the anal canal and rectum by anoscopy and proctoscopy to ensure the source of ongoing bleeding is not distal to the planned resection margin (Fig. 29-7).Occult blood loss from the gastrointestinal tract may mani-fest as iron-deficiency anemia or may be detected with FOBT or FIT. Because colon neoplasms bleed intermittently and rarely present with rapid hemorrhage, the presence of occult fecal blood should always prompt a colonoscopy. Unexplained iron-deficiency


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Surgery_Schwartz. FOBT or FIT. Because colon neoplasms bleed intermittently and rarely present with rapid hemorrhage, the presence of occult fecal blood should always prompt a colonoscopy. Unexplained iron-deficiency anemia is also an indication for colonoscopy.Hematochezia is commonly caused by hemorrhoids or a fissure. Sharp, knife-like pain and bright red rectal bleeding with bowel movements suggest the diagnosis of fissure. Pain-less, bright red rectal bleeding with bowel movements is often secondary to a friable internal hemorrhoid that is easily detected by anoscopy. In the absence of a painful, obvious fissure, any patient with rectal bleeding should undergo a careful digital rectal examination, anoscopy, and proctosigmoidoscopy. Fail-ure to diagnose a source in the distal anorectum should prompt colonoscopy.Constipation and Obstructed Defecation. Constipation is an extremely common complaint, affecting more than 4 million people in the United States. Despite the prevalence of this prob-lem,


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Surgery_Schwartz. colonoscopy.Constipation and Obstructed Defecation. Constipation is an extremely common complaint, affecting more than 4 million people in the United States. Despite the prevalence of this prob-lem, there is lack of agreement about an appropriate definition of constipation. Patients may describe infrequent bowel move-ments, hard stools, or excessive straining. A careful history of these symptoms often clarifies the nature of the problem.Constipation has many causes. Underlying metabolic, pharmacologic, endocrine, psychological, and neurologic causes often contribute to the problem. A stricture or mass lesion should be excluded by colonoscopy, barium enema, or CT colonography. After these causes have been excluded, eval-uation focuses on differentiating slow-transit constipation from outlet obstruction. Transit studies, in which radiopaque markers are swallowed and then followed radiographically, are useful for diagnosing slow-transit constipation. In this study, patients ingest


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Surgery_Schwartz. outlet obstruction. Transit studies, in which radiopaque markers are swallowed and then followed radiographically, are useful for diagnosing slow-transit constipation. In this study, patients ingest radiopaque studies and are followed radiographically for 5 days. Retention of 20% or greater of these markers in the colon demonstrated slow transit. If these markers are congregated in the rectosigmoid colon and rectum, obstructed defecation/outlet obstruction is suggested. Anorectal manometry and EMG can detect nonrelaxation of the puborectalis, which contributes to outlet obstruction. The absence of an anorectal inhibitory reflex Massive life-threatening bleedingPositiveRebleedingRebleedingModerate bleedingcontinuedBleeding stopped or slowed downPositivePositivePositivePositivePositivePositivePositivePositiveNegativeNegativeNegativeNegativeNegativeNegativeNegativeNegativeNegativeFailFailorAcute colonic bleedingVolume resuscitationplus blood transfusionNG aspiratenegativeNG


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Surgery_Schwartz. colonic bleedingVolume resuscitationplus blood transfusionNG aspiratenegativeNG aspiratepositiveProctoscopyRule out anorectal bleedingGastroduodenoscopy+ endoscopic treatmentElective colonoscopyMesenteric arteriographyMesenteric arteriographyUrgent colonoscopy99MTc RBC scintigraphyColonoscopic treatmentor explore, segmentalresectionEndoscopictreatmentVasopressinor emboliVasopressinor emboliExplore, intraoperativeendoscopyExplore, intraoperativeendoscopyExplore, intraoperativeendoscopyExplore, intraoperativeendoscopyObserveSegmentalresectionTotalcolectomyTotalcolectomyTotalcolectomyTotalcolectomySegmentalresectionSegmentalresectionSegmentalresectionSegmentalresectionSegmentalresectionSegmentalresectionSee moderate bleedingor massive bleedingFigure 29-7. Algorithm for treatment of colorectal hemorrhage. NG = nasogastric; 99mTc = technetium-99; RBC = red blood cell. (Repro-duced with permission of Gordon PH, Nivatvongs S: Principles and Practice of Surgery for the Colon, Rectum, and


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Surgery_Schwartz. hemorrhage. NG = nasogastric; 99mTc = technetium-99; RBC = red blood cell. (Repro-duced with permission of Gordon PH, Nivatvongs S: Principles and Practice of Surgery for the Colon, Rectum, and Anus, 2nd ed. New York, NY: Marcel Dekker, Inc; 1999.)Brunicardi_Ch29_p1259-p1330.indd 126823/02/19 2:28 PM 1269COLON, RECTUM, AND ANUSCHAPTER 29suggests Hirschsprung’s disease and may prompt a rectal muco-sal biopsy. Defecography can identify rectal prolapse, intussus-ception, rectocele, or enterocele.Medical management is the mainstay of therapy for consti-pation and includes fiber, increased fluid intake, and laxatives. Outlet obstruction from nonrelaxation of the puborectalis or anal sphincter dyssynergy often responds to biofeedback. Surgery to correct rectocele and rectal prolapse (with or without sigmoid resection) has a variable effect on symptoms of constipation but can be successful in selected patients. Subtotal colectomy is considered only for patients with severe slow-transit


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Surgery_Schwartz. or without sigmoid resection) has a variable effect on symptoms of constipation but can be successful in selected patients. Subtotal colectomy is considered only for patients with severe slow-transit consti-pation (colonic inertia) refractory to maximal medical inter-ventions. While this operation almost always increases bowel movement frequency, complaints of diarrhea, incontinence, and abdominal pain are not infrequent, and patients should be care-fully selected and counseled.11Diarrhea and Irritable Bowel Syndrome. Diarrhea is also a common complaint and is usually a self-limited symptom of infectious gastroenteritis. If diarrhea is chronic or is accom-panied by bleeding or abdominal pain, further investigation is warranted. Bloody diarrhea and pain are characteristic of colitis; etiology can be an infection (invasive E coli, Shigella, Salmonella, Campylobacter, Entamoeba histolytica, or C difficile), inflammatory bowel disease (ulcerative colitis or Crohn’s coli-tis), or


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Surgery_Schwartz. etiology can be an infection (invasive E coli, Shigella, Salmonella, Campylobacter, Entamoeba histolytica, or C difficile), inflammatory bowel disease (ulcerative colitis or Crohn’s coli-tis), or ischemia. Stool wet-mount and culture can often diag-nose infection. Sigmoidoscopy or colonoscopy can be helpful in diagnosing inflammatory bowel disease or ischemia. However, if the patient has abdominal tenderness, particularly with peri-toneal signs, or any other evidence of perforation, endoscopy is contraindicated.Chronic diarrhea may present a more difficult diagnos-tic dilemma. Chronic ulcerative colitis, Crohn’s colitis, infec-tion, malabsorption, and short gut syndrome can cause chronic diarrhea. Rarely, carcinoid syndrome and islet cell tumors (vasoactive intestinal peptide–secreting tumor [VIPoma], somatostatinoma, gastrinoma) present with this symptom. Large villous lesions may cause secretory diarrhea. Collagenous colitis can cause diarrhea without any obvious mucosal


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Surgery_Schwartz. tumor [VIPoma], somatostatinoma, gastrinoma) present with this symptom. Large villous lesions may cause secretory diarrhea. Collagenous colitis can cause diarrhea without any obvious mucosal abnor-mality. Along with stool cultures, tests for malabsorption, and metabolic investigations, colonoscopy can be invaluable in dif-ferentiating these causes. Biopsies should be taken even if the colonic mucosa appears grossly normal.Irritable bowel syndrome is a particularly troubling con-stellation of symptoms consisting of crampy abdominal pain, bloating, constipation, and urgent diarrhea. Workup reveals no underlying anatomic or physiologic abnormality. Once other disorders have been excluded, dietary restrictions and avoid-ance of caffeine, alcohol, and tobacco may help to alleviate symptoms. Antispasmodics and bulking agents may be helpful.Incontinence. The true incidence of fecal incontinence is unknown, but has been estimated to occur in 10 to 13 individu-als per 1000 people older than


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Surgery_Schwartz. Antispasmodics and bulking agents may be helpful.Incontinence. The true incidence of fecal incontinence is unknown, but has been estimated to occur in 10 to 13 individu-als per 1000 people older than age 65 years. Incontinence ranges in severity from occasional leakage of gas and/or liquid stool to daily loss of solid stool. The underlying cause of incontinence is often multifactorial, and diarrhea is often contributory. In gen-eral, causes of incontinence can be classified as neurogenic or anatomic. Neurogenic causes include diseases of the central ner-vous system and spinal cord along with pudendal nerve injury. Anatomic causes include congenital abnormalities, procidentia (rectal prolapse), overflow incontinence secondary to impac-tion or an obstructing neoplasm, and trauma. The most common Figure 29-8. A. Endoanal ultrasonography showing the normal layers of the anal canal. B. Endoanal ultrasonography with anterior sphincter defect from birthing injury. EAS = external anal


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Surgery_Schwartz. most common Figure 29-8. A. Endoanal ultrasonography showing the normal layers of the anal canal. B. Endoanal ultrasonography with anterior sphincter defect from birthing injury. EAS = external anal sphincter; IAS = internal anal sphincter. (Used with permission from Charles O. Finne III, MD, Minneapolis, MN.)ABtraumatic cause of incontinence is injury to the anal sphincter during vaginal delivery. Other causes include anorectal surgery, impalement, and pelvic fracture.After a thorough medical evaluation to detect underly-ing conditions that might contribute to incontinence, evalua-tion focuses on assessment of the anal sphincter and pudendal nerves. Pudendal nerve terminal motor latency testing may detect neuropathy. Anal manometry can detect low resting and squeeze pressures. Physical examination and defecography can detect rectal prolapse. Endoanal ultrasound is invaluable in diagnosing sphincter defects (Fig. 29-8).Therapy depends on the underlying abnormality. Diarrhea should be


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Surgery_Schwartz. and defecography can detect rectal prolapse. Endoanal ultrasound is invaluable in diagnosing sphincter defects (Fig. 29-8).Therapy depends on the underlying abnormality. Diarrhea should be treated medically (fiber, antidiarrheal agents). Even in the absence of frank diarrhea, the addition of dietary fiber may improve continence. Some patients may respond to bio-feedback and this approach may be considered in patients who fail dietary modification. Many patients with a sphincter defect are candidates for an overlapping sphincteroplasty. Sacral nerve Brunicardi_Ch29_p1259-p1330.indd 126923/02/19 2:28 PM 1270SPECIFIC CONSIDERATIONSPART IIstimulation been shown to decrease episodes of fecal incon-tinence and has proven durability in the long term (5 years). The artificial bowel sphincter may be useful in patients who fail other interventions. Other options include radiofrequency energy to the anal canal (SECCA procedure), magnetic anal sphincter, and injectable submucosal bulking


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Surgery_Schwartz. may be useful in patients who fail other interventions. Other options include radiofrequency energy to the anal canal (SECCA procedure), magnetic anal sphincter, and injectable submucosal bulking agents, but long-term efficacy has not yet been proven.12-14 Finally, a stoma can provide relief for severely incontinent patients who have failed or are not candidates for other interventions.GENERAL SURGICAL CONSIDERATIONSColorectal resections are performed for a wide variety of condi-tions, including neoplasms (benign and malignant), inflamma-tory bowel diseases, and other benign conditions. Although the indication and urgency for surgery will alter some of the tech-nical details, the operative principles of colorectal resections, anastomoses, and use of ostomies are well established.ResectionsThe mesenteric clearance technique dictates the extent of colonic resection and is determined by the nature of the primary pathology (malignant or benign), the intent of the resection (curative or


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Surgery_Schwartz. mesenteric clearance technique dictates the extent of colonic resection and is determined by the nature of the primary pathology (malignant or benign), the intent of the resection (curative or palliative), the precise location(s) of the primary pathology, and the condition of the mesentery (thin and soft or thick and indurated). In general, a proximal mesenteric ligation will eliminate the blood supply to a greater length of colon and require a more extensive “colectomy.” Curative resection of a colorectal cancer is usually best accomplished by performing a proximal mesenteric vessel ligation and radical mesenteric clearance of the lymphatic drainage basin of the tumor site (Fig. 29-9). Resection of a benign process does not require wide mesenteric clearance.Emergency Resection. Emergency resection may be required because of obstruction, perforation, or hemorrhage. In this set-ting, the bowel is almost always unprepared and the patient may be unstable. The surgical principles


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Surgery_Schwartz. resection may be required because of obstruction, perforation, or hemorrhage. In this set-ting, the bowel is almost always unprepared and the patient may be unstable. The surgical principles described earlier apply, and an attempt should be made to resect the involved segment along with its lymphovascular supply. If the resection involves the right colon or proximal transverse colon (right or extended right colectomy), a primary ileocolonic anastomosis can usually be performed safely as long as the remaining bowel appears healthy and the patient is stable. For left-sided tumors, the traditional approach has involved resection of the involved bowel and end colostomy, with or without a mucus fistula. However, there is an increasing body of data to suggest that a primary anasto-mosis without a bowel preparation or with an on-table lavage, with or without a diverting ileostomy, may be equally safe in this setting. If the proximal colon appears unhealthy (vascular compromise, serosal


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Surgery_Schwartz. a bowel preparation or with an on-table lavage, with or without a diverting ileostomy, may be equally safe in this setting. If the proximal colon appears unhealthy (vascular compromise, serosal tears, perforation), a subtotal colectomy can be performed with a small bowel to rectosigmoid anastomo-sis. Resection and diversion (ileostomy or colostomy) remain safe and appropriate if the bowel appears compromised or if the patient is unstable, malnourished, or immunosuppressed.Minimally Invasive Techniques of Resection. With advances in minimally invasive technology, many proce-dures that previously have required laparotomy can now be performed laparoscopically, with hand-assisted laparoscopy (HAL), or robotically.15,16 Potential advantages of minimally invasive surgery include improved cosmetic result, decreased postoperative pain, and earlier return of bowel function. More-over, some experimental data suggest that minimally invasive 1operations have less immunosuppressive impact on the


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Surgery_Schwartz. result, decreased postoperative pain, and earlier return of bowel function. More-over, some experimental data suggest that minimally invasive 1operations have less immunosuppressive impact on the patient and thus might improve postoperative outcome and even long-term survival. To date, most studies have demonstrated equiva-lence between laparoscopic, HAL, and open resection in terms of extent of resection. Return of bowel function and length of hospital stay are highly variable. Long-term outcome has yet to be determined; however, short-term quality of life appears to be improved by laparoscopy.17,18 Laparoscopic total mesorec-tal excision for rectal cancer, however, may not be appropriate. The most recent advances in minimally invasive surgery involve use of robotics and telemanipulation in which the surgeon oper-ates from a console remote from the patient. These procedures have been rapidly gaining in popularity, especially for pelvic and rectal resections. Early studies suggest


Surgery_Schwartz

Surgery_Schwartz. in which the surgeon oper-ates from a console remote from the patient. These procedures have been rapidly gaining in popularity, especially for pelvic and rectal resections. Early studies suggest equivalence between robotic resections and laparoscopic/HAL resections.19In addition, some proponents have suggested that robotic procedures may be easier to learn (a shorter “learning curve”) and that robotic surgery may be ergonomically better for the operating surgeon. Nevertheless, long-term superiority, or even equivalence, has yet to be demonstrated, and these advanced technologies are likely to be associated with significant cost.Colectomy. A variety of terms are used to describe different types of colectomy (Fig. 29-10).Ileocolic Resection An ileocolic resection describes a limited resection of the terminal ileum, cecum, and appendix. It is used to remove disease involving these segments of the intestine (e.g., ileocecal Crohn’s disease) and benign lesions or incur-able cancers


Surgery_Schwartz

Surgery_Schwartz. resection of the terminal ileum, cecum, and appendix. It is used to remove disease involving these segments of the intestine (e.g., ileocecal Crohn’s disease) and benign lesions or incur-able cancers arising in the terminal ileum, cecum, and, occa-sionally, the appendix. If curable malignancy is suspected, more radical resections, such as a right hemicolectomy, are gener-ally indicated. The ileocolic vessels are ligated and divided. A variable length of small intestine may be resected depending on the disease process. A primary anastomosis is created between the distal small bowel and the ascending colon. It is technically difficult to perform an anastomosis at or just proximal to the ileocecal valve; therefore, if the most distal ileum needs to be resected, the cecum is generally also removed.Right Colectomy A right colectomy is used to remove lesions or disease in the right colon and is oncologically the most appro-priate operation for curative intent resection of proximal colon


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Surgery_Schwartz. removed.Right Colectomy A right colectomy is used to remove lesions or disease in the right colon and is oncologically the most appro-priate operation for curative intent resection of proximal colon carcinoma. The ileocolic vessels, right colic vessels, and right branches of the middle colic vessels are ligated and divided. Approximately 10 cm of terminal ileum are usually included in the resection. A primary ileal-transverse colon anastomosis is almost always possible.Extended Right Colectomy An extended right colectomy may be used for curative intent resection of lesions located at the hepatic flexure or proximal transverse colon. A standard right colectomy is extended to include ligation of the middle colic vessels at their base. The right colon and proximal trans-verse colon are resected, and a primary anastomosis is created between the distal ileum and distal transverse colon. Such an anastomosis relies on the marginal artery of Drummond. If the blood supply to the distal


Surgery_Schwartz

Surgery_Schwartz. resected, and a primary anastomosis is created between the distal ileum and distal transverse colon. Such an anastomosis relies on the marginal artery of Drummond. If the blood supply to the distal transverse colon is questionable, the resection is extended distally beyond the splenic flexure to well-perfused descending colon where the ileocolic anastomosis can be performed safely.Transverse Colectomy Lesions in the mid and distal trans-verse colon may be resected by ligating the middle colic vessels and resecting the transverse colon, followed by a colocolonic anastomosis. However, an extended right colectomy with an Brunicardi_Ch29_p1259-p1330.indd 127023/02/19 2:28 PM 1271COLON, RECTUM, AND ANUSCHAPTER 29anastomosis between the terminal ileum and descending colon may be a safer anastomosis with an equivalent functional result.Left Colectomy For lesions or disease states confined to the distal transverse colon, splenic flexure, or descending colon, a left colectomy is performed.


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Surgery_Schwartz. with an equivalent functional result.Left Colectomy For lesions or disease states confined to the distal transverse colon, splenic flexure, or descending colon, a left colectomy is performed. The left branches of the middle colic vessels, the left colic vessels, and the first branches of the sigmoid vessels are ligated. A colocolonic anastomosis can usually be performed.Extended Left Colectomy An extended left colectomy is an option for removing lesions in the distal transverse colon. In this operation, the left colectomy is extended proximally to include the right branches of the middle colic vessels.Sigmoid Colectomy Lesions in the sigmoid colon require ligation and division of the sigmoid branches of the inferior mesenteric artery. In general, the entire sigmoid colon should be resected to the level of the peritoneal reflection and an BADCFEFigure 29-9. Extent of resection for carcinoma of the colon. A. Cecal cancer. B. Hepatic flexure cancer. C. Transverse colon cancer. D.


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Surgery_Schwartz. to the level of the peritoneal reflection and an BADCFEFigure 29-9. Extent of resection for carcinoma of the colon. A. Cecal cancer. B. Hepatic flexure cancer. C. Transverse colon cancer. D. Splenic flexure cancer. E. Descending colon cancer. F. Sigmoid colon cancer.Brunicardi_Ch29_p1259-p1330.indd 127123/02/19 2:28 PM 1272SPECIFIC CONSIDERATIONSPART IIanastomosis created between the descending colon and upper rectum. Full mobilization of the splenic flexure is often required to create a tension-free anastomosis.Total and Subtotal Colectomy Total or subtotal colectomy is occasionally required for patients with fulminant colitis, attenu-ated FAP, or synchronous colon carcinomas. In this procedure, the ileocolic vessels, right colic vessels, middle colic vessels, and left colic vessels are ligated and divided. The superior rectal vessels are preserved. If it is desired to preserve the sigmoid, the distal sigmoid vessels are left intact, and an anastomosis is created between the


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Surgery_Schwartz. are ligated and divided. The superior rectal vessels are preserved. If it is desired to preserve the sigmoid, the distal sigmoid vessels are left intact, and an anastomosis is created between the ileum and distal sigmoid colon (subtotal colectomy with ileosigmoid anastomosis). If the sigmoid is to be resected, the sigmoidal vessels are ligated and divided, and the ileum is anastomosed to the upper rectum (total abdominal colectomy with ileorectal anastomosis). If an anastomosis is contraindicated, an end ileostomy is created, and the remain-ing sigmoid or rectum is managed either as a mucus fistula or a Hartmann’s pouch.Proctocolectomy Total Proctocolectomy In this procedure, the entire colon, rectum, and anus are removed, and the ileum is brought to the skin as a Brooke ileostomy.Restorative Proctocolectomy (Ileal Pouch–Anal Anasto-mosis) The entire colon and rectum are resected, but the anal sphincter muscles and a variable portion of the distal anal canal are preserved. Bowel


Surgery_Schwartz

Surgery_Schwartz. Proctocolectomy (Ileal Pouch–Anal Anasto-mosis) The entire colon and rectum are resected, but the anal sphincter muscles and a variable portion of the distal anal canal are preserved. Bowel continuity is restored by anastomosis of an ileal reservoir to the anal canal. The original technique included a transanal mucosectomy and hand-sewn ileoanal anastomosis. Proponents of this technique argue that mucosectomy guarantees removal of all of the diseased mucosa, including the anal transi-tion zone, and therefore decreases the risk of ongoing disease, dysplasia, and carcinoma. Opponents cite the increased risk of incontinence after mucosectomy and argue that even meticulous technique invariably leaves behind mucosal “islands” that are subsequently hidden under the anastomosis. However, persistent or recurrent dysplasia in the anal transition zone is uncommon (4.5%), and cancers occur even more rarely.19 Moreover, the “double-staple” technique using the circular stapling devices is


Surgery_Schwartz

Surgery_Schwartz. persistent or recurrent dysplasia in the anal transition zone is uncommon (4.5%), and cancers occur even more rarely.19 Moreover, the “double-staple” technique using the circular stapling devices is considerably simpler than mucosectomy and a hand-sewn anas-tomosis and may be associated with a better functional outcome (Fig. 29-11).20-22 Regardless of the anastomotic technique, many surgeons recommend that patients undergo annual surveillance of the anastomosis and/or anal transition zone by digital rectal exam and anoscopy or proctoscopy.The neorectum is made by anastomosis of the terminal ileum aligned in a “J,” “S,” or “W” configuration. Because func-tional outcomes are similar and because the J-pouch is the sim-plest to construct, it has become the most used configuration. ABCDEFGHIJKLFigure 29-10. Terminology of types of colorectal resections: A→C Ileocecectomy; + A + B→D Ascending colectomy; + A + B→F Right hemicolectomy; + A + B→G Extended right hemi-colectomy; + E + F→G + H


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Surgery_Schwartz. 29-10. Terminology of types of colorectal resections: A→C Ileocecectomy; + A + B→D Ascending colectomy; + A + B→F Right hemicolectomy; + A + B→G Extended right hemi-colectomy; + E + F→G + H Transverse colectomy; G→I Left hemicolectomy; F→I Extended left hemicolectomy; J + K Sigmoid colectomy; + A + B→J Subtotal colectomy; + A + B→K Total col-ectomy; + A + B→L Total proctocolectomy. (Reproduced with per-mission from Fielding LP, Goldberg SM: Rob & Smith’s Operative: Surgery of the Colon, Rectum, and Anus. London: Elsevier; 1993.)BCAFigure 29-11. After a total colectomy and resection of the rec-tum (A), the anal canal with a short cuff of transitional mucosa and sphincter muscles is preserved (B). An ileal J-pouch has been constructed and is anastomosed to the anal canal using a double-staple technique (C). (Reproduced with permission from Bell RH, Rikkers LF, Mulholland M: Digestive Tract Surgery: A Text and Atlas. Philadelphia, PA: Lippincott Williams & Wilkins;


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Surgery_Schwartz. using a double-staple technique (C). (Reproduced with permission from Bell RH, Rikkers LF, Mulholland M: Digestive Tract Surgery: A Text and Atlas. Philadelphia, PA: Lippincott Williams & Wilkins; 1996.)Brunicardi_Ch29_p1259-p1330.indd 127223/02/19 2:29 PM 1273COLON, RECTUM, AND ANUSCHAPTER 29With increasing experience in laparoscopic and robotic colec-tomy, some centers have begun performing total proctocolec-tomy with ileal pouch–anal reconstruction using minimally invasive surgical techniques.15 Most surgeons perform a proxi-mal ileostomy to divert succus from the newly created pouch in an attempt to minimize the consequences of leak and sepsis, especially in patients who are malnourished or immunosup-pressed (Fig. 29-12). The ileostomy is then closed 6 to 12 weeks later, after a contrast study confirms the integrity of the pouch. In low-risk patients, however, there are reports of successful creation of an ileoanal pouch without a diverting stoma.Anterior Resection. Anterior


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Surgery_Schwartz. contrast study confirms the integrity of the pouch. In low-risk patients, however, there are reports of successful creation of an ileoanal pouch without a diverting stoma.Anterior Resection. Anterior resection is the general term used to describe resection of the rectum from an abdominal approach to the pelvis with no need for a perineal, sacral, or other incision. Three types of anterior resection have been described.High Anterior Resection A high anterior resection is the term used to describe resection of the distal sigmoid colon and upper rectum and is the appropriate operation for benign lesions and disease at the rectosigmoid junction such as diverticulitis. The upper rectum is mobilized, but the pelvic peritoneum is not divided and the rectum is not mobilized fully from the concavity of the sacrum. The inferior mesenteric artery is ligated at its base, and the inferior mesenteric vein, which follows a different course than the artery, is ligated separately. A primary


Surgery_Schwartz

Surgery_Schwartz. concavity of the sacrum. The inferior mesenteric artery is ligated at its base, and the inferior mesenteric vein, which follows a different course than the artery, is ligated separately. A primary anasto-mosis (usually end-to-end) between the colon and rectal stump with a short cuff of peritoneum surrounding its anterior two thirds generally can be performed.Low Anterior Resection. A low anterior resection is used to remove lesions in the upper and mid rectum. The rectosigmoid is mobilized, the pelvic peritoneum is opened, and the inferior mesenteric artery is ligated and divided either at its origin from the aorta or just distal to the takeoff of the left colic artery. The rectum is mobilized from the sacrum by sharp dissection under direct view within the endopelvic fascial plane. The dissec-tion may be performed distally to the anorectal ring, extend-ing posteriorly through the rectosacral fascia to the coccyx and anteriorly through Denonvilliers’ fascia to the vagina in women or


Surgery_Schwartz

Surgery_Schwartz. dissec-tion may be performed distally to the anorectal ring, extend-ing posteriorly through the rectosacral fascia to the coccyx and anteriorly through Denonvilliers’ fascia to the vagina in women or the seminal vesicles and prostate in men. The rectum and accompanying mesorectum are divided at the appropriate level, depending on the nature of the lesion. A low rectal anastomosis usually requires mobilization of the splenic flexure and ligation and division of the inferior mesenteric vein just inferior to the pancreas. Circular stapling devices have greatly facilitated the conduct and improved the safety of the colon to extraperitoneal rectal anastomosis.Extended Low Anterior Resection An extended low anterior resection is necessary to remove lesions located in the distal rectum, but several centimeters above the sphincter. The rectum is fully mobilized to the level of the levator ani muscle just as for a low anterior resection, but the anterior dissection is extended along the


Surgery_Schwartz

Surgery_Schwartz. several centimeters above the sphincter. The rectum is fully mobilized to the level of the levator ani muscle just as for a low anterior resection, but the anterior dissection is extended along the rectovaginal septum in women and distal to the semi-nal vesicles and prostate in men. After resection at this level, a coloanal anastomosis can be created using one of a variety of techniques. An end-to-end stapled or hand-sewn anastomo-sis has traditionally been the procedure of choice. However, the functional consequences of a “straight” anastomosis have led to consideration for creation of a colon J-pouch to increase the capacity of the neorectal reservoir. A side-to-end anastomosis can be constructed by placing the anvil of an EEA stapler 3 to 4 cm away from the stapled end of the proximal colon, with simi-lar functional outcomes to the colon J-pouch reconstruction.20-22 Because the risk of an anastomotic leak and subsequent sepsis is higher when an anastomosis is created in the distal


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Surgery_Schwartz. colon, with simi-lar functional outcomes to the colon J-pouch reconstruction.20-22 Because the risk of an anastomotic leak and subsequent sepsis is higher when an anastomosis is created in the distal rectum or anal canal, creation of a temporary ileostomy should be consid-ered in this setting, especially if the patient has received neoad-juvant radiation.23Although an anastomosis may be technically feasible very low in the rectum or anal canal, it is important to note that post-operative function may be poor. Because the descending colon lacks the distensibility of the rectum, the reservoir function may be compromised. Pelvic radiation, prior anorectal surgery, and obstetrical trauma may cause unsuspected sphincter damage. Finally, a very low anastomosis may involve and compromise the upper sphincter. Creation of a colon J-pouch or transverse coloplasty may improve function, but few long-term studies have addressed this issue.20-22A history of sphincter damage or any degree of


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Surgery_Schwartz. the upper sphincter. Creation of a colon J-pouch or transverse coloplasty may improve function, but few long-term studies have addressed this issue.20-22A history of sphincter damage or any degree of inconti-nence is a relative contraindication for a coloanal anastomosis. In such patients, an end colostomy may be a more satisfac-tory option.Hartmann’s Procedure and Mucus Fistula. Hartmann’s procedure refers to a colon or rectal resection without an 2Figure 29-12. Ileal S-pouch anal anastomosis with temporary loop ileostomy. (Reproduced with permission from Bell RH, Rikkers LF, Mulholland M: Digestive Tract Surgery: A Text and Atlas. Philadelphia, PA: Lippincott Williams & Wilkins; 1996.)Brunicardi_Ch29_p1259-p1330.indd 127323/02/19 2:29 PM 1274SPECIFIC CONSIDERATIONSPART IIanastomosis in which a colostomy or ileostomy is created and the distal colon or rectum is left as a blind pouch. The term is typically used when the left or sigmoid colon is resected and the closed off rectum


Surgery_Schwartz

Surgery_Schwartz. in which a colostomy or ileostomy is created and the distal colon or rectum is left as a blind pouch. The term is typically used when the left or sigmoid colon is resected and the closed off rectum is left in the pelvis. If the distal colon is long enough to reach the abdominal wall, a mucus fistula can be created by opening the defunctioned bowel and suturing the open lumen to the skin.Abdominoperineal Resection. An abdominoperineal resec-tion (APR) involves removal of the entire rectum, anal canal, and anus with construction of a permanent colostomy from the descending or sigmoid colon. The abdominal-pelvic portion of this operation proceeds in the same fashion as described for an extended low anterior resection. The perineal dissection can be performed with the patient in lithotomy position (often by a second surgeon) or in the prone position after closure of the abdomen and creation of the colostomy. For cancer, the perineal dissection is designed to excise the anal canal with a


Surgery_Schwartz

Surgery_Schwartz. (often by a second surgeon) or in the prone position after closure of the abdomen and creation of the colostomy. For cancer, the perineal dissection is designed to excise the anal canal with a wide cir-cumferential margin including a cylindrical cuff of the levator muscle. A deliberate resection of the levator muscles near their bony attachments, in order to avoid opening the space between the tumor and the levator ani, is known as the extralevator abdomi-noperineal resection (ELAPE). ELAPE is useful for low, locally advanced rectal cancers, but routine use for all rectal cancer has not been shown to improve cancer outcomes.24 Primary wound closure is usually successful, but a large perineal defect, espe-cially if preoperative radiation has been used, may require a vascularized flap closure in some patients.25 For benign disease, proctectomy may be performed using an intersphincteric dissec-tion between the internal and external sphincters. This approach minimizes the perineal wound,


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Surgery_Schwartz. in some patients.25 For benign disease, proctectomy may be performed using an intersphincteric dissec-tion between the internal and external sphincters. This approach minimizes the perineal wound, making it easier to close because the levator muscle remains intact.AnastomosesAnastomoses may be created between two segments of bowel in a multitude of ways. The geometry of the anastomosis may be end-to-end, end-to-side, side-to-end, or side-to-side. The anas-tomotic technique may be hand-sewn or stapled (Fig. 29-13). The submucosal layer of the intestine provides the strength of the bowel wall and must be incorporated in the anastomosis to assure healing. The choice of anastomosis depends on the opera-tive anatomy and surgeon preference. Although many surgeons advocate one method over another, none has been proven to be superior. Accurate approximation of two well-vascularized, healthy limbs of bowel without tension in a normotensive, well-nourished patient almost always results in a


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Surgery_Schwartz. none has been proven to be superior. Accurate approximation of two well-vascularized, healthy limbs of bowel without tension in a normotensive, well-nourished patient almost always results in a good outcome. Anastomoses at highest risk of leak or stricture are those that are in the distal rectal or anal canal, involve irradiated or dis-eased intestine including perforation with peritoneal soilage, are inadvertently fashioned above a partial distal obstruction, or are performed in malnourished, immunosuppressed, or ill patient.Anastomotic Configuration End-to-End An end-to-end anastomosis can be performed when two segments of bowel are roughly the same caliber. This technique is most often employed in rectal resections, but may be used for colocolostomy or small bowel anastomoses.End-to-Side An end-to-side configuration is useful when one limb of bowel is larger than the other. This most commonly occurs in the setting of chronic obstruction.Side-to-End A side-to-end anastomosis is used


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Surgery_Schwartz. end-to-side configuration is useful when one limb of bowel is larger than the other. This most commonly occurs in the setting of chronic obstruction.Side-to-End A side-to-end anastomosis is used when the proxi-mal bowel is of smaller caliber than the distal bowel. Ileorectal anastomoses commonly make use of this configuration. A side-to-end anastomosis may have a less tenuous blood supply than an end-to-end anastomosis.Side-to-Side A side-to-side anastomosis allows a large, well-vascularized connection to be created on the antimesenteric side of two segments of intestine. This technique is commonly used in ileocolic and small bowel anastomoses.Anastomotic Technique Hand-Sutured Technique Any of the configurations described earlier may be created using a hand-sutured or stapled technique. Hand-sutured anastomoses may be single layer, using either running or interrupted stitches, or double layer. A double-layer anastomosis usually consists of a continuous inner layer and an interrupted


Surgery_Schwartz

Surgery_Schwartz. Hand-sutured anastomoses may be single layer, using either running or interrupted stitches, or double layer. A double-layer anastomosis usually consists of a continuous inner layer and an interrupted outer layer. Suture material may be either perma-nent or absorbable. After distal rectal or anal canal resection, a transanal, hand-sewn coloanal anastomosis may be necessary to restore bowel continuity. This can be done in conjunction with an anal canal mucosectomy to allow the anastomosis to be cre-ated at the dentate line.Stapled Techniques Linear cutting/stapling devices are used to divide the bowel and to create side-to-side anastomoses. The anastomosis may be reinforced with interrupted sutures if desired. Circular cutting/stapling devices can create end-to-end, end-to-side, or side-to-end anastomoses. These instruments are particularly useful for creating low rectal or anal canal anas-tomoses where the anatomy of the pelvis makes a hand-sewn anastomosis technically difficult or


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Surgery_Schwartz. anastomoses. These instruments are particularly useful for creating low rectal or anal canal anas-tomoses where the anatomy of the pelvis makes a hand-sewn anastomosis technically difficult or impossible.Following resection of the colorectum, a stapled end-to-end colorectal, coloanal canal, or ileal pouch–anal canal anasto-mosis may be created by one of two techniques. With the open purse-string technique, the distal rectal stump purse-string is placed by hand, and the assembled circular stapler is inserted into the anus and guided up to the rectal purse-string. The sta-pler is opened, and the distal purse-string is tied. A purse-string is placed in the distal end of the proximal colon; the proximal colon is placed over the anvil and the purse-string tightened. The stapler is closed and fired (Fig. 29-14). With the alterna-tive double-staple technique, the distal rectum or anal canal is closed with a transverse staple line. The circular stapler is inserted through the anus without its


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Surgery_Schwartz. (Fig. 29-14). With the alterna-tive double-staple technique, the distal rectum or anal canal is closed with a transverse staple line. The circular stapler is inserted through the anus without its anvil until the cartridge effaces the transverse staple line. The stapler is opened, causing the trocar to perforate through the rectal stump adjacent to the transverse staple line. The anastomosis in then completed as described earlier (see Fig. 29-11). If the stapler cannot advance to the end of the rectal stump, further dissection of the stump may be necessary to optimize tissue apposition. After firing and removing the stapler, the resulting anastomotic rings should be inspected to ensure that they are full-thickness and concentric, and in cases of rectal cancer, the distal anastomotic ring should be sent to pathology as a specimen (true distal margin). A gap in an anastomotic ring suggests that the circular staple line is incomplete and the anastomosis should be reinforced with suture