Neurology_Adams

Neurology_Adams. For some reason, there was little awareness of the frequency and importance of spondylotic myelopathy for many years after these early observations had been made. All the interest was in the acute ruptured disc. Finally, it was Russell Brain who, in 1948, put cervical spondylosis on the neurologic map, so to speak. He drew a distinction between acute rupture and protrusion of the cervical disc (often traumatic and more likely to compress the nerve roots than the spinal cord) and chronic spinal cord and root compression consequent to disc degeneration and associated osteophytic outgrowths (hard disc), as well as changes in the surrounding joints and ligaments. In 1957, Payne and Spillane documented the importance of a developmentally smaller-than-normal spinal canal in the genesis of myelopathy in patients with cervical spondylosis. These reports were followed by a spate of articles on the subject (see Wilkinson). Rowland’s review of the natural history of cervical spondylosis and the


Neurology_Adams

Neurology_Adams. in patients with cervical spondylosis. These reports were followed by a spate of articles on the subject (see Wilkinson). Rowland’s review of the natural history of cervical spondylosis and the results of surgical therapy is a useful modern reference, as is that by Uttley and Monro.


Neurology_Adams

Neurology_Adams. The characteristic syndrome consists of combinations of the following in varying degrees: (1) painful, stiff neck or pain in the neck, shoulders, and upper arms (brachialgia) that may be aching or radicular (stabs of sharp and radiating pain evoked by movement), asymmetric or unilateral; (2) numbness and paresthesias of the hands; and (3) spastic leg weakness with Babinski signs, unsteadiness of gait, and a Romberg sign. The numbness and paresthesias are occasionally the earliest symptoms and typically involve the distal limbs, especially the hands. Variations of these symptoms are elaborated below. Each of the components may occur separately, or they may occur in combination, particularly myelopathy with radiculopathy.


Neurology_Adams

Neurology_Adams. With reference to the most common of these symptoms, the neck and shoulder pain, in any sizable group of patients older than 50 years of age, approximately 40 percent will be found at times to have some clinical abnormality of the neck, usually crepitus or pain, with restriction of lateral flexion and rotation (less often of extension). Pallis and colleagues, in a survey of 50 patients, all of them older than 50 years of age and none with neurologic complaints, found that 75 percent showed radiologic evidence of narrowing of the cervical spinal canal as a result of osteophytosis of the posterior vertebral bodies or of narrowing of the intervertebral foramina because of osteoarthropathy at the apophyseal joints; thickening of the ligaments (both the ligamentum flavum posteriorly and the posterior longitudinal ligament anteriorly) adds to the narrowing of the canal. However, only half of the patients with radiologic abnormalities showed physical signs of root or cord involvement such as


Neurology_Adams

Neurology_Adams. longitudinal ligament anteriorly) adds to the narrowing of the canal. However, only half of the patients with radiologic abnormalities showed physical signs of root or cord involvement such as changes in the tendon reflexes in the arms, briskness of reflexes and impairment of vibratory sense in the legs, and sometimes Babinski signs. The occasional finding of a Babinski sign in older individuals who had never had a stroke or complained of neurologic symptoms is often explained by an otherwise inevident cervical osteophyte (Savitsky and Madonick).


Neurology_Adams

Neurology_Adams. The pain is usually centered at the base of the neck or higher, often radiating to an area above the scapula. When brachialgia is also present, it takes several forms: a sharp pain in the preor postaxial border of the limb, extending to the elbow, wrist, or fingers; or a persistent dull ache in the forearm or wrist, sometimes with a burning sensation. Discomfort may be elicited by coughing, Valsalva maneuver, or neck extension, or neck flexion may induce electrical feelings down the spine (Lhermitte symptom). Rarely, the pain is referred substernally.


Neurology_Adams

Neurology_Adams. As to the sensory features (which may occasionally be absent), numbness, tingling, and prickling of the hands and soles of the feet and around the ankles are the most frequent complaints. Some patients complain of numbness or paresthesias, most often in one or two digits, a part of the palm, or a longitudinal band along the forearm. Slight clumsiness or weakness of a hand is another complaint. A feeling as if “wearing gloves,” “swollen,” or the hands “coated with glue” are common descriptions. Several of our patients have complained of paresthesias in the distal limbs and trunk for years before there was any indication of motor involvement. In advanced cases, there may be a vague sensory level at or just above the clavicles. Impaired vibratory sensation and diminished position sense in the toes and feet (all indicative of a lesion of the posterior columns), as well as the Romberg sign, are the most conspicuous sensory findings. This imparts a “tabetic” unsteadiness to the gait.


Neurology_Adams

Neurology_Adams. in the toes and feet (all indicative of a lesion of the posterior columns), as well as the Romberg sign, are the most conspicuous sensory findings. This imparts a “tabetic” unsteadiness to the gait. Sensory defects tend to be asymmetrical. (It is noteworthy that symmetric sensory symptoms and signs of identical type are seen with subacute combined degeneration as a result of vitamin B12 deficiency.) Less frequently, paresthesias and dysesthesias in the lower extremities and trunk may be the principal symptoms; even less often there are sensory complaints on the face, ostensibly corresponding to compression of the trigeminal sensory tract in the upper cervical cord. Rarely, the sensorimotor pattern takes the form of a Brown-Séquard syndrome.


Neurology_Adams

Neurology_Adams. The third part of the typical syndrome, spastic legs from a compressive myelopathy, most often manifests as a complaint of weakness of a leg or of getting upstairs and slight unsteadiness of gait. The entire leg or the quadriceps feels stiff and heavy and gives out quickly after exercise. Mobility of the ankle may be reduced, and the advancing toe of the shoe scrapes the floor. On examination, slight hypertonicity of the legs is usually more evident than weakness, and the tendon reflexes are increased (ankle jerks may not share in this change in the elderly). Although the patient may believe that only one leg is affected, it is commonly found that both plantar reflexes are extensor, the one on the side of the stiffer leg being more clearly so. Less often, both legs are equally affected. As the compression continues, walking becomes unsteady because of the addition of sensory ataxia.


Neurology_Adams

Neurology_Adams. The biceps and brachioradial reflexes on one or both sides may be depressed, sometimes in association with an increase in the triceps and finger reflexes. The hand or forearm muscles may undergo atrophy; in a few cases, the atrophy of hand muscles is severe. In such cases, the spondylotic compression, as judged by MRI or CT myelography, may be confined to the high cervical cord, well above the levels of the motor neurons that innervate these muscles. In patients with sensory loss, pain and thermal sensation often appear to be affected more than tactile sense. An unexpected Babinski sign has already been mentioned and a few fasciculations may be seen, especially in proximal arm muscles. Another unusual feature in advanced stages of cervical cord compression is the appearance of mirror movements of the hands, in which effortful attempts to make refined movements of the fingers of one hand, causes the opposite hand to move similarly.


Neurology_Adams

Neurology_Adams. As the myelopathy progresses, sometimes intermittently, both legs become weaker and more spastic. Sphincteric control may then be altered; slight hesitancy and precipitancy of micturition are the usual complaints; frank incontinence is infrequent. In the more advanced form of this condition, walking requires the aid of a cane or canes or a walker; in some cases, all locomotion ultimately becomes impossible, especially in the elderly patient. Abrupt worsening, even paraplegia or quadriplegia, may follow forceful traumatic flexion or extension injuries of the neck, as indicated later.


Neurology_Adams

Neurology_Adams. The fundamental lesion of the spinal column is probably generated initially by a fraying of the annulus fibrosus with extrusion of disc material into the spinal canal. The disc becomes covered with fibrous tissue or partly calcified, thereby forming a transverse osteophytic “spondylitic bar” or there may be simply central bulging of the annulus without extrusion of nuclear material. The latter, unlike ruptured discs that occur mainly at the C5-C6 or C6-C7 interspace, often involve higher interspaces and may occur at several adjacent levels. The dura may be thickened and adherent to the posterior longitudinal ligament at affected levels. The underlying pia-arachnoid is also thickened and the adjacent ligamentous hypertrophy contributes to compression of the cord or the nerve roots. This series of pathologic changes is often ascribed to a type of hypertrophic osteoarthritis. However, osteophyte formation and ridging are so frequently observed in patients who have no other signs of


Neurology_Adams

Neurology_Adams. series of pathologic changes is often ascribed to a type of hypertrophic osteoarthritis. However, osteophyte formation and ridging are so frequently observed in patients who have no other signs of arthritic disease that this explanation is surely not totally correct. Subclinical trauma in persons who are structurally susceptible to spondylosis is more likely to be the cause of bar formation, in the authors’ opinion.


Neurology_Adams

Neurology_Adams. When a cervical nerve root is compressed by lateral osteophytic overgrowth, the dural sleeve is thickened and truncated and the root fibers are damaged. Usually the fifth, sixth, or seventh cervical roots are affected in this way, both the anterior and posterior, or only the anterior, on one or both sides. A small neuroma may rarely appear proximal to the site of anterior root compression.


Neurology_Adams

Neurology_Adams. The dura is ridged and the underlying spinal cord is flattened. The root lesions may lead to secondary wedge-shaped areas of degeneration in the lateral parts of the posterior columns at higher levels. The most marked changes in the spinal cord are at the level(s) of compression. There are zones of demyelination or focal necrosis at the points of attachment of the dentate ligaments (which tether the spinal cord to the dura) and areas of rarefaction in the posterior and lateral columns, as well as loss of nerve cells. Ventral gray matter lesions, often asymmetrical, are attributed by Hughes to ischemia. The vulnerability of the cervical spine to degenerative change has no ready explanation. Most likely it is related in some way to the high degree of mobility of the lower cervical vertebrae, which is accentuated by their location next to the relatively immobile thoracic spine.


Neurology_Adams

Neurology_Adams. The mechanism of spinal cord injury would seem to be one of simple compression and ischemia. When the spinal canal is developmentally narrow in its anteroposterior dimension at one or several points, the space available for the spinal cord becomes insufficient. A small canal certainly makes an individual more subject to the compressive effects of spondylosis. The range acquired of narrowing of the canal that produces symptomatic cervical spondylosis is generally from 7 to 12 mm (normal canal diameter: 17 to 18 mm). Consequently, one must consider several additional mechanisms by which the cord might be damaged. The effects of the natural motions of the spinal cord during flexion and extension of the neck are probably important in this respect. Adams and Logue confirmed the observation of O’Connell that, during full flexion and extension of the neck, the cervical cord and dura move up and down. The spinal cord is literally dragged over protruding osteophytes and hypertrophied


Neurology_Adams

Neurology_Adams. of O’Connell that, during full flexion and extension of the neck, the cervical cord and dura move up and down. The spinal cord is literally dragged over protruding osteophytes and hypertrophied ligaments; conceivably it is this type of intermittent trauma that causes progressive injury.


Neurology_Adams

Neurology_Adams. It has also been shown that the spinal cord, displaced posteriorly by osteophytes, is compressed by the infolding of the posterolateral ligamentum flavum each time the neck is extended (Stoltmann and Blackwood). Segmental ischemic necrosis resulting from intermittent compression of spinal arteries or from compression of the anterior spinal artery has also been postulated. Most neuropathologists favor the idea of intermittent cord compression between osteophytes anteriorly and ligamentum flavum posteriorly, with an added vascular element accounting for the scattered lesions deep in the cord. Trauma from sudden extreme extension, as in a fall, severe whiplash injury, or chiropractic manipulation, or from a lesser degree of retraction of the head during myelography, tooth extraction, or a tonsillectomy may be operative in individual cases, particularly in patients with congenitally narrow canals. The lateral extension of the osteophyte and hypertrophy of the adjacent facet joint together


Neurology_Adams

Neurology_Adams. may be operative in individual cases, particularly in patients with congenitally narrow canals. The lateral extension of the osteophyte and hypertrophy of the adjacent facet joint together compress the nerve root as it is entering its spinal foramen. Sometimes these are the main changes and cause only a radiculopathy, as discussed in Chap. 10.


Neurology_Adams

Neurology_Adams. When pain and stiffness in the neck, brachialgia, either in the form of aching or a more distinctive radicular pain, and sensorimotor-reflex changes in the arms are combined with signs of myelopathy, there is little difficulty in diagnosis. When the neck and arm changes are inconspicuous or absent, the diagnosis becomes more difficult. The myelopathy must then be distinguished from the late, progressive form of spinal multiple sclerosis. Because posterior vertebral osteophytes and other bony alterations are frequent in the sixth and seventh decades of life, the question that must be answered in any given case is whether the vertebral changes are adequately severe to cause the neurologic abnormality. The finding of some degree of sensorimotor or reflex change corresponding only to the level of the spinal abnormalities is a point that always favors spondylotic myelopathy. A lack of such corresponding changes and the presence of oligoclonal bands and signs of lesions in the optic nerves


Neurology_Adams

Neurology_Adams. of the spinal abnormalities is a point that always favors spondylotic myelopathy. A lack of such corresponding changes and the presence of oligoclonal bands and signs of lesions in the optic nerves and brain indicate demyelinating myelopathy.


Neurology_Adams

Neurology_Adams. The detailed findings on both MRI and CT myelography become critical in such cases (Fig. 42-9). The MRI may overestimate the degree of cord compression by an osteophyte, but clear deformation of the cord into the shape of a kidney bean and obliteration of the surrounding CSF spaces in the transverse image support the diagnosis of spondylotic compression. To confidently attribute neurologic symptoms to spondylosis there should be considerable encroachment on and obliteration of the circumferential CSF space at that level, not simply an impingement or slight deformation of the normal oval shape of the cord. Signal changes within the body of the cord underlying or within a half segment of the compression are seen in advanced cases and usually indicate a degree of irreversibility of at least the sensory symptoms. Curiously, these signal changes may be one or two levels above or below the site of main compression. A purportedly specific imaging sign of a transverse “pancake-like”


Neurology_Adams

Neurology_Adams. at least the sensory symptoms. Curiously, these signal changes may be one or two levels above or below the site of main compression. A purportedly specific imaging sign of a transverse “pancake-like” gadolinium enhancement at and just caudal to the site of maximal compression has been suggested by Flanagan and colleagues (2014). However, serious symptoms may occur even without changes in the intrinsic MRI signal. Contrast myelography with the patient supine and lateral views taken during flexion and extension of the neck are useful diagnostic procedures in uncertain cases.


Neurology_Adams

Neurology_Adams. It has been stated that spondylotic myelopathy may simulate amyotrophic lateral sclerosis (amyotrophy of arms and spastic weakness of the legs). This has seldom been a diagnostic problem. Although brachial and shoulder fasciculations with muscle atrophy may be combined with hyperreflexia in spondylosis, the widespread denervation and progressive course of ALS are not in evidence. We have observed only a few patients with spondylotic myelopathy who exhibited an absolutely pure motor syndrome, that is, one in which there was no cervical or brachial pain and no sensory symptoms in the arms or impairment of vibratory or position sense in the legs. Likewise, a pure spastic paraparesis is more likely to be a manifestation of MS, hereditary spastic paraplegia, motor neuron disease (primary lateral sclerosis type), HTLV-I myelopathy, or the carrier state of adrenoleukodystrophy or other intrinsic myelopathy.


Neurology_Adams

Neurology_Adams. When imbalance, both perceived by the patient and observed in tests of walking, is a major symptom, spondylosis must be differentiated from a number of acquired large-fiber polyneuropathies, particularly inflammatory or immune types and the more benign sensory neuropathy of the aged (see discussion of this entity in Chap. 43). Loss of tactile sensation in the feet and loss of tendon reflexes are characteristic of the latter; examination of the tendon reflexes distinguishes neuropathy from myelopathy. Subacute combined degeneration of the spinal cord because of vitamin B12 deficiency or low serum copper, AIDS and HTLV-I myelopathy, ossification of the posterior longitudinal ligament, and spinal cord tumor (discussed further on) are usually listed among the conditions that might be confused with spondylotic myelopathy. The gait abnormality produced by spondylotic myelopathy may also be mistaken for that of normal-pressure hydrocephalus; a marked increase of imbalance with removal of


Neurology_Adams

Neurology_Adams. with spondylotic myelopathy. The gait abnormality produced by spondylotic myelopathy may also be mistaken for that of normal-pressure hydrocephalus; a marked increase of imbalance with removal of visual cues (Romberg sign) is a feature of spondylosis but not of hydrocephalus, and the short-stepped and magnetic quality of walking, that is, characteristic of hydrocephalus is not seen in cervical myelopathy (see Chap. 29 for discussion of NPH). Incontinence occurs only in advanced cases of spondylotic myelopathy but usually follows soon after gait deterioration in hydrocephalus.


Neurology_Adams

Neurology_Adams. The special problems of spondylotic radiculopathy, which may accompany or occur independently of the myelopathy, are discussed in Chap. 10. The slow, intermittently progressive course of cervical myelopathy with long periods of relatively unchanging symptomatology makes it difficult to evaluate the effects of treatment. Assuming that the prevailing view of the mechanism of cord and root compression is correct, the use of a soft collar to restrict anteroposterior motions of the neck seems reasonable. This form of immobilization may be sufficient to reduce discomfort in the neck and arms; only exceptionally in our experience, however, has arm and shoulder pain alone been sufficiently severe and persistent to require surgical decompression unless there is in addition a laterally protruded disc or osteophytic constriction of a root foramen. Many patients have been dissatisfied with the results of this passive approach and are unable to wear a collar for prolonged periods.


Neurology_Adams

Neurology_Adams. If osteophytes have narrowed the spinal canal at several interspaces, a posterior decompressive laminectomy with severance of the dentate ligaments helps to prevent further injury but the procedure has been partly supplanted by anterior approaches to decompression of the spinal canal. The results of a posterior procedure in relieving symptoms are fairly satisfactory (Epstein and Epstein); in fully two-thirds of the patients, improvement in the function of the legs occurs, and in most of the others, progression of the myelopathy is halted. The operation carries some risk; rarely, an acute quadriplegia—presumably a result of manipulation of the spinal cord and damage to spinal arteries—has followed the surgical procedure. When only one or two interspaces are the site of osteophytic compression, their removal by an anterior approach (anterior cervical discectomy with [or without] fixation, or “ACDF”) has given better results and carries less risk. Braakman has reviewed the surgical


Neurology_Adams

Neurology_Adams. their removal by an anterior approach (anterior cervical discectomy with [or without] fixation, or “ACDF”) has given better results and carries less risk. Braakman has reviewed the surgical methods and their relative advantages.


Neurology_Adams

Neurology_Adams. Even with modern surgical techniques, most series indicate that once symptomatic, the outcome varies and that a significant proportion of patients, even after adequate decompression and initial improvement, have persistent symptoms or undergo some degree of later functional deterioration (see also Chap. 10). This creates a conundrum for the physician in advising the patient about the correct time to undertake surgical decompression. Nonetheless, certain clinical observations pertain and may be used as guides to treatment. Any degree of spasticity, sphincter disturbance, or loss of sensation in the hands will not improve or will improve little, and indeed usually worsens over months, without surgery. Hand weakness and muscular atrophy that is the result of radicular compression will improve with decompression of the appropriate root by one of several surgical approaches, but weakness that is from central cord damage requires decompression to halt the process and probably should not be


Neurology_Adams

Neurology_Adams. with decompression of the appropriate root by one of several surgical approaches, but weakness that is from central cord damage requires decompression to halt the process and probably should not be delayed more than a few weeks once it is apparent that this is the problem. Usually, such patients have MRI signal changes within the substance of the cervical cord in apposition to an osteophytic bar.


Neurology_Adams

Neurology_Adams. Lumbar Stenosis (See Chap. 10) This is another spondylotic abnormality seen with particular frequency in older individuals, especially men. Usually it declares itself by numbness and weakness of the legs, sometime with poor control of sphincters. Many texts state that there may be little or no pain or only a spinal ache that fluctuates from day to day but in our experience the majority of patients have constant backache and sciatica. A notable feature is the induction or aggravation of the neurologic symptoms upon standing and walking (neurologic claudication). This topic is discussed in “Lumbar Stenosis” in Chap. 10, which should be consulted for a detailed discussion.


Neurology_Adams

Neurology_Adams. This condition of the spine is a result of inflammation at the sites of ligamentous insertions into bone that leads to an intense calcification. The sacroiliac joints and lumbar spine are most affected, as discussed in Chap. 10, but as the disease advances, the entire spine becomes fused and rigid. The biomechanics of the rigid spine make it susceptible to fracture. The most common complication is a spinal stenosis and cauda equina syndrome. Bartleson and associates described 14 patients (and referred to 30 others in the medical literature) who, years after the onset of spondylitis, developed sensory, motor, reflex, and sphincteric disorders referable to L4, L5, and the sacral roots. Surprisingly, the spinal canal was not narrowed but instead the caudal sac was actually dilated. Confavreux and coworkers presented evidence that enlargement of the lumbar dural sac is caused by a defect in resorption of the CSF. There are usually arachnoidal diverticula on the posterior root sleeves, but


Neurology_Adams

Neurology_Adams. and coworkers presented evidence that enlargement of the lumbar dural sac is caused by a defect in resorption of the CSF. There are usually arachnoidal diverticula on the posterior root sleeves, but no other explanation can be given for the radicular symptoms and signs. Surgical decompression has not benefited most patients, nor has corticosteroid therapy.


Neurology_Adams

Neurology_Adams. This condition occasionally occurs at higher levels and gives rise to a myelopathy. Our experience includes several cases with symptoms related to the cervical roots. The most hazardous complication of ankylosing spondylitis is compression of the cord from seemingly minor trauma that has resulted in fracture–dislocation of the cervical (or lumbar) vertebrae. Fox and colleagues treated 31 such patients in a 5-year period; the majority of unstable fractures that required surgical fixation were in the cervical region, and several patients had fracture–dislocations at two levels. The instability at the upper spinal levels may be difficult to detect radiologically, and caution should be observed in allowing patients to resume full activity after a neck injury if the cervical spine is involved by ankylosing spondylitis. Careful flexion and extension radiograph views usually, but not always, demonstrate the instability.


Neurology_Adams

Neurology_Adams. As mentioned briefly earlier, multiple arachnoid cysts in the thoracic or lumbar region are associated with ankylosing spondylitis (and with Marfan syndrome). Rheumatoid Arthritis of the Spine


Neurology_Adams

Neurology_Adams. Rheumatoid Arthritis of the Spine The spinal changes of rheumatoid arthritis differ somewhat from those of ankylosing spondylitis although the latter too may be a cause of atlantoaxial dislocation (see further on under “Anomalies at the Craniocervical Junction”). The ligaments that attach the odontoid to the atlas and to the skull and the joint tissue are weakened by the destructive inflammatory process. The subsequent dislocation of the atlas on the axis may remain mobile or become fixed and give rise to an intermittent or persistent paraparesis or quadriparesis. Similar effects may result from a forward subluxation of C4 on C5 (see Nakano et al). Atlantoaxial dislocation is known to be a cause of collapse and sudden death. If the upper cervical cord is compressed, the odontoid process must be removed and C1-C2 decompressed and stabilized. Other levels of the spine are less frequently affected. Ossification of the Posterior Longitudinal


Neurology_Adams

Neurology_Adams. Ossification of the Posterior Longitudinal Compressive cervical myelopathy caused by this process occurs almost exclusively in patients of Japanese extraction and has been demonstrated to us as an almost mundane finding by colleagues in Hawaii. The clinical signs are much the same as those of cervical spondylosis, but the radiologic appearance of cancellous bone along a segment of the posterior longitudinal ligament is unique. The ligamentous calcification can be seen on plain films, CT and MRI as a vertical longitudinal row of calcification and may be mistaken for spondylotic change. The ossified areas may enlarge enough to form islands of bone marrow. Laminoplasty with enlargement of the spinal canal has been successful.


Neurology_Adams

Neurology_Adams. This unusual myelopathy has usually been considered in discussions of the motor neuron disorders because of its characteristic features of chronic wasting of one, or less often, or both hands and forearms without sensory changes or long tract signs. It appears, however, that the damage in this disease is from intermittent compression of the lower cervical cord and gradual deterioration of the motor neurons in the anterior grey matter. Hirayama’s group pointed out that in the young men who were affected, the mechanism of cord damage is a buckling of the dorsal dural sac and an intermittent anterior displacement and ligamentous compression of the cord during flexion of the neck. Although the disorder is highlighted as occurring mainly in Asia, we continue to see cases from the United States sporadically.


Neurology_Adams

Neurology_Adams. The muscles innervated by C7, C8, and T1, encompassing mainly the hand and forearm, are affected on one side or bilaterally, but almost always markedly asymmetrically. There are few or no fasciculations and no sensory changes; the painless loss of power and muscle bulk proceeds smoothly over several years, giving the impression of a degenerative condition. MRI or CT myelogram performed with the neck flexed, as described by Hirayama and Tokumaru, shows the cervical cord to be atrophic with signal changes in the anterior parts of the cord and confirms the diagnosis of compression by the buckled dura. We have examined several such patients and can corroborate their claim from observation of MRI with the patient placed in a flexed-neck position. Presumably, this configuration causes ischemia of the anterior gray matter, but this has not been proved. Others have reported the syndrome in the absence of this structural configuration (Willeit et al). Two of our young male patients had long


Neurology_Adams

Neurology_Adams. of the anterior gray matter, but this has not been proved. Others have reported the syndrome in the absence of this structural configuration (Willeit et al). Two of our young male patients had long swan-like necks. What is most important about this process is the degree of recovery afforded by ligamentous sectioning and by similar surgical approaches that accomplish decompression of the lower cervical cord.


Neurology_Adams

Neurology_Adams. Paget Disease of the Spine (Osteitis Deformans) Enlargement of the vertebral bodies, pedicles, and laminae in Paget disease may result in narrowing of the spinal canal. The clinical picture is one of cord compression. The plasma alkaline phosphatase concentration is high, and the typical bone changes are seen in radiographs. Usually, several adjacent vertebrae of the thoracic spine are affected but other parts of the skeleton are also involved (see later), which facilitates diagnosis. Posterior surgical decompression leaving the pedicles intact is indicated if there is sufficient stability of the vertebral bodies to prevent collapse. Medical management includes the use of nonsteroidal anti-inflammatory drugs for persistent pain; calcitonin to reduce pain and plasma levels of alkaline phosphatase; and cytotoxic drugs such as plicamycin and etidronate disodium to reduce bone resorption.


Neurology_Adams

Neurology_Adams. The spinal cord is obviously vulnerable to any vertebral maldevelopment or disease that encroaches upon the spinal canal or compresses its nutrient arteries. Some well-known abnormalities are listed here. Congenital Anomalies at the Craniocervical Junction Of these, congenital fusion of the atlas and foramen magnum is the most common. McCrae, who described the radiologic features of more than 100 patients with bony abnormalities at the craniocervical junction, found this partial or complete bony union of the atlas and occipital bone in 28 cases. He also noted that whenever the anteroposterior diameter of the canal behind the odontoid process was less than 19 mm, there were signs of spinal cord compression. Fusion of the second and third cervical vertebrae is a common associated anomaly but does not seem to be of clinical significance. There is considerable crossover with the foreshortened neck of the Klippel-Feil syndrome mentioned below.


Neurology_Adams

Neurology_Adams. Abnormalities of the odontoid process These were found in 17 cases of McCrae’s series. There may be complete separation of the odontoid from the axis or chronic atlantoaxial dislocation (atlas displaced anteriorly in relation to the axis). These abnormalities may be congenital or the result of injury and are known causes of acute or chronic spinal cord compression and stiffness of the neck. In all the congenital anomalies of the foramen magnum and the upper cervical spine there is a high incidence of syringomyelia. McCrae found that 38 percent of all patients with syringomyelia and syringobulbia showed such bony anomalies, but this is considerably higher than in our experience. All patients whose symptoms might be explained by a lesion in the cervicocranial region (particularly patients in whom MS and foramen magnum tumor are suspected) require careful radiologic examination.


Neurology_Adams

Neurology_Adams. In mucopolysaccharidosis IV, or the Morquio syndrome (Chap. 36), a typical feature is the absence or severe hypoplasia of the odontoid process. This abnormality, combined with laxity or redundancy of the surrounding ligaments, results in atlantoaxial subluxation and compression of the spinal cord. Affected children refuse to walk or develop spastic weakness of the limbs. Early in life they excrete an excess of keratan sulfate, but this may no longer be detectable in adult life. In certain of the mucopolysaccharidoses, we have also seen a true pachymeningopathy with great thickening of the dura in the basal cisterns and high cervical region with spinal cord compression. Surgical decompression and spinal immobilization have been curative.


Neurology_Adams

Neurology_Adams. Achondroplasia This dominantly inherited form of dwarfism is caused by a mutation in one of the fibroblastic growth factors, which causes a failure of conversion of fetal cartilage to bone at the growth plate. It occasionally results in great thickening of the vertebral bodies, neural arches, laminae, and pedicles because of increased periosteal bone formation. The spinal canal is narrowed in the thoracolumbar region, often with kyphosis, leading sometimes to a progressive spinal cord or cauda equina syndrome. Another complication, which results from a small foramen magnum, is hydrocephalus (or markedly widened subarachnoid spaces). In young children, a syndrome of central apnea and spasticity of the legs is characteristic. These complications may require ventricular shunting. Narrowing of the lumbar canal tends to present later in life.


Neurology_Adams

Neurology_Adams. Platybasia and basilar invagination Platybasia refers to a flattening of the base of the skull (the angle formed by intersection of the plane of the clivus and the plane of the anterior fossa is greater than 135 degrees). Basilar impression or invagination has a somewhat different meaning, namely, an upward bulging of the occipital condyles; if the condyles, which bear the thrust of the spine, are displaced above the plane of the foramen magnum, basilar invagination is present. Each of these abnormalities may be congenital or acquired (as in Paget disease); frequently they are combined. They give rise to a characteristic shortness of the neck and a combination of cerebellar and spinal signs. A normal-pressure hydrocephalus may also develop.


Neurology_Adams

Neurology_Adams. In the Klippel-Feil syndrome there is fusion of the upper cervical vertebrae or of the atlas to the occiput. The anomaly is easily identified by substantial foreshortening of the neck. Affected individuals are susceptible to compression of the cervical cord after minor trauma. Many such patients demonstrate mirror movements of their hands, comparable to those described earlier in cervical spondylosis. Tethered cord This developmental anomaly is discussed more fully and illustrated in Chap. 37. A progressive cauda equina syndrome with prominent urinary difficulties and varying degrees of spasticity are the usual presentations.


Neurology_Adams

Neurology_Adams. Here, as in multiple sclerosis, the degree of ataxia and spastic weakness is variable. A few patients have an almost pure state of spastic weakness of the legs, requiring differentiation from motor system disease and familial spastic paraplegia. Such a syndrome, formerly called Erb spastic paraplegia and attributed to meningovascular syphilis, is now recognized as being nonspecific and more often caused by demyelinating disease. In a minority of chronic syphilitic patients, sensory ataxia and other posterior column signs predominate. Ventral roots are involved in the chronic meningeal inflammation, giving rise to signs of segmental amyotrophy—hence the term syphilitic amyotrophy of the upper extremities with spastic paraplegia. Confirmation of this now infrequent diagnosis depends on finding a lymphocytic pleocytosis, an elevated protein and gamma globulin, and a positive serologic reaction in the CSF. Other aspects of this disease and treatment are discussed under “Spinal Syphilis”


Neurology_Adams

Neurology_Adams. a lymphocytic pleocytosis, an elevated protein and gamma globulin, and a positive serologic reaction in the CSF. Other aspects of this disease and treatment are discussed under “Spinal Syphilis” in Chap. 31. Tabes dorsalis is, of course, another important form of syphilitic myelitis.


Neurology_Adams

Neurology_Adams. Subacute Combined Degeneration of the Spinal Cord (See Chap. 40) This form of nutritional spinal cord disease is caused by vitamin B12 deficiency and is fully described in Chap. 40. Almost invariably it begins with bilateral symptoms and signs of posterior column involvement in the hands (paresthesias and reduced touch, pressure, and joint sensibility), which, if untreated, is followed within a matter of several weeks or months by progressive spastic paraparesis because of involvement of the corticospinal tracts to which a vague sensory level on the trunk may be added. Particular importance attaches to the fact that this is a treatable disease and that the degree of reversibility is dependent upon the duration of symptoms before specific treatment is begun. Copper Deficiency Myelopathy (Combined System Disease of Nonpernicious Anemia Type)


Neurology_Adams

Neurology_Adams. This refers to a metabolic disease of the spinal cord caused by low copper, affecting the posterior and lateral columns, in this sense, also a combined system degeneration. The clinical syndrome and potential causes were elegantly elaborated by Kumar and colleagues. A homologous disease exists as “swayback” in lambs. A deficiency of vitamin B12 is not causative, but may coexist in some cases, probably on the basis of a shared inadequacy of dietary intake. Women are more often affected than men. Imbalance is the most common presenting complaint. Posterior column signs and gait ataxia tend to predominate but a degree of spasticity is usually conjoined and there may be Babinski signs and reduced ankle reflexes. The problem is typically one of impaired absorption of copper, for example, after gastric bypass or bowel surgery, which together account for half of cases. Of importance in causation in some patients is excess zinc intake in the form of health supplements, coin swallowing, and


Neurology_Adams

Neurology_Adams. gastric bypass or bowel surgery, which together account for half of cases. Of importance in causation in some patients is excess zinc intake in the form of health supplements, coin swallowing, and denture creams (see Nations et al).


Neurology_Adams

Neurology_Adams. There is an associated hypocupremic anemia with ringed sideroblasts and leukopenia with vacuolated myeloid precursors in the marrow that may be mistaken for a myelodysplastic process. The idiopathic variety has certain similarities to the disorder of copper mobilization in Menkes disease, but the disordered enzyme responsible in the latter has been normal. As reported by others, in a recent case on our service without explanation for the discovered copper deficiency, MRI of the cervical cord revealed distinctive signal changes in both the posterior and lateral columns identical to those of B12 deficiency, and these were no longer present after copper treatment. The majority of affected patients have abnormal somatosensory evoked potentials with delays in central conduction.


Neurology_Adams

Neurology_Adams. Treatment Oral copper supplementation, 2 mg/d for at least several months, seems effective in most patients, but some do not improve and the appropriate duration of treatment is unknown. Some patients relapse after an initial improvement even with continued administration or when copper supplementation is stopped. The gluconate, sulfate, or chloride preparations of copper may be used, although there has been concern about the bioavailability of the first-named compound. Intravenous therapy as a way of initially replenishing copper stores has been introduced but the need for such treatment is uncertain. Zinc supplements must, of course, be discontinued, as they lower copper levels.


Neurology_Adams

Neurology_Adams. There remains a group of subacute ataxic-spastic myelopathies that are not caused by multiple sclerosis or by B12 or copper deficiency. Progressive spastic or spastic-ataxic paraparesis of a chronic, irreversible type may also develop in conjunction with chronic, decompensated liver disease; with AIDS; in cases of adrenoleukodystrophy, particularly in the symptomatic female heterozygote; in tropical spastic paraplegia (HTLV-I); radiation myelopathy; and adhesive spinal arachnoiditis, which is discussed immediately below. Spinal Arachnoiditis (Chronic Adhesive Arachnoiditis) (See Chap. 10)


Neurology_Adams

Neurology_Adams. This is now a relatively uncommon spinal cord disorder that was introduced in relation to the subject of low back pain in Chap. 10. It is characterized by a combination of painful root and spinal cord symptoms that may mimic intraspinal tumor. There is opacification and thickening of the arachnoidal membranes and adhesions between the arachnoid and dura—the result of proliferation of connective tissue. The subarachnoid space is unevenly obliterated. In this sense, the term arachnoiditis is not entirely appropriate, although it seems likely that the connective tissue overgrowth is a reaction to an antecedent arachnoidal inflammation. Some forms of arachnoiditis were traced to syphilis or to a subacute, therapeutically resistant meningitis of another type. Most others in the past followed the introduction of a variety of substances, most no longer used, into the subarachnoid space for diagnostic or therapeutic purposes or following spinal anesthesia, soon afterward or after an interval


Neurology_Adams

Neurology_Adams. introduction of a variety of substances, most no longer used, into the subarachnoid space for diagnostic or therapeutic purposes or following spinal anesthesia, soon afterward or after an interval of weeks, months, or even years. This complication was eventually traced to a detergent that had contaminated vials of procaine.


Neurology_Adams

Neurology_Adams. More pernicious, however, is a delayed meningomyelopathy that developed within a few months or years of the inciting event, causing a spastic paralysis, sensory loss, and incontinence of sphincters. There are also cases on record in which an epidural or similar catheter has accidentally penetrated the cord and caused a traumatic partial myelopathy as mentioned earlier. Still seen regularly is a restricted form of arachnoiditis that complicates a series of operations for lumbar discs or the spinal injection of methylene blue. Less convincing are cases attributed to closed spinal injuries. In many cases, no provocative factor can be recognized. A familial form was reported by Duke and Hashimoto, but we have had no experience with it.


Neurology_Adams

Neurology_Adams. Clinical manifestations Symptoms may occur in close temporal relation to an acute arachnoidal inflammation or may be delayed for weeks, months, or even years as indicated above. The most common mode of onset is with pain in the distribution of one or more sensory nerve roots, first on one side, then on both, in the lumbofemoral regions. The pain has a burning, stinging, or aching quality and is persistent. Abnormalities of tendon reflexes are common, but weakness and atrophy, the results of damage to anterior roots, are less frequent. In thoracic lesions, symptoms of root involvement may antedate those of cord compression by months or years. Sooner or later, however, there is involvement of the spinal cord, manifest by a slowly progressive spastic ataxia with sphincter disturbances.


Neurology_Adams

Neurology_Adams. The localized lumbar arachnoiditis associated with repeated disc surgery (the common variety seen in pain clinics) is characterized by back and or leg pain with other inconstant signs of radiculopathy (loss of tendon reflexes, weakness, and variable degrees of sensory loss), usually bilateral.


Neurology_Adams

Neurology_Adams. The CSF is abnormal during the acute stage in practically all cases that ultimately result in adhesive arachnoiditis. In some there is a moderate lymphocytic pleocytosis, occurring soon after the inciting event. In the localized lumbar arachnoiditis, referred to earlier, the CSF may be normal or show only a slight increase in protein content. The prominent finding with imaging is a partial or complete obliteration of the spinal subarachnoid space. The loculated myelographic appearance of arachnoiditis is characteristic (patchy dispersion of the column of dye and a “candle-guttering” appearance that was most evident with oil-based contrast media); MRI reveals a loss of the normal ring of CSF or localized loculations of CSF (see Fig. 10-6).


Neurology_Adams

Neurology_Adams. Treatment In the early stages of arachnoiditis, corticosteroids have been given to control the inflammatory reaction and to prevent progress of the disease, but their value is questionable. Surgery may be effective in the case of localized “cyst” formation and cord compression. Severe radicular pain can be effectively relieved by posterior rhizotomy, but there is a strong tendency for the pain to return after an interval of several months or 1 or 2 years so that this approach has been all but abandoned. For chronic adhesive lumbar arachnoiditis in which diffuse back and limb pain is the most distressing symptom, there is little effective surgical or medical treatment, although relief has reportedly been provided in isolated instances by painstaking microsurgical dissection of the lumbar roots. In some cases, the loculations return. Administration of corticosteroids, systemic and epidural, has not been consistently beneficial but may be tried. Immune-suppressant medication such as


Neurology_Adams

Neurology_Adams. roots. In some cases, the loculations return. Administration of corticosteroids, systemic and epidural, has not been consistently beneficial but may be tried. Immune-suppressant medication such as azathioprine or interferons have been tried but not studied systematically. Transcutaneous stimulator treatment and gabapentin have also been used with inconsistent results.


Neurology_Adams

Neurology_Adams. Herniation of the Cord Through a Dural Tear Violent trauma to the spinal canal or skull such as a fall or blow to the back can cause arachnoidal and dural tears. The associated neural injury dominates the picture and the dural tear may require repair so as to minimize the development of meningitis. More difficult to understand is the occurrence of spinal cord herniation through a spontaneous rent in the adjacent dura with no preceding injury. In view of the fact that we have encountered five such instances in a decade, without trauma having occurred, it is probably not rare.


Neurology_Adams

Neurology_Adams. In the typical case, a vertically oriented tear of limited extent occurs in the ventral dura overlying the midor high-thoracic region, and a segment of the spinal cord protrudes through it into the epidural space. The result is a painless, subacute, and incomplete spinal cord syndrome, which reaches a plateau and leaves the patient with an asymmetrical spastic paraparesis and variable sensory loss. There are reports of a Brown-Séquard hemi-cord syndrome and variations of it as described in the small series by Watters and colleagues. Orthostatic headache of low-CSF pressure is not usually part of the syndrome. MRI or CT myelopathy demonstrates the protruded segment of the cord where it buckles through the dura. Presumably the herniation creates a sufficient degree of local ischemia or mechanical disturbance to account for the myelopathic symptoms. Surgical restoration of the cord to its proper position and repair of the tear, have resulted in partial or complete return of neurologic


Neurology_Adams

Neurology_Adams. disturbance to account for the myelopathic symptoms. Surgical restoration of the cord to its proper position and repair of the tear, have resulted in partial or complete return of neurologic function (Vallee et al).


Neurology_Adams

Neurology_Adams. As to the cause of this condition, a congenital duplication of the dura membranes combined with herniation through the inner layer has been observed in some cases at operation. The abnormal configuration of the membrane has been proposed as a cause of the propensity for the fibers to separate and create an aperture. Compression of the spinal cord by a metastatic tumor in the vertebral column is a common occurrence in many types of cancers. Primary tumors of the spinal cord are considerably less frequent. In the Mayo Clinic series of 8,784 primary tumors of the CNS, only 15 percent were intraspinal (Sloof et al). In contradistinction to brain tumors, the majority of intraspinal ones is benign and produces effects mainly by compression of the spinal cord rather than by invasion. Thus, a proportion of intraspinal tumors are amenable to surgical removal, and their early recognition, before irreversible neurologic changes have occurred, becomes a matter of utmost importance.


Neurology_Adams

Neurology_Adams. General Considerations of Neoplastic Compression of the Cord (See Also Chap. 30)


Neurology_Adams

Neurology_Adams. Neoplasms and other space-occupying lesions within the spinal canal can be divided into two groups: (1) those that arise within the substance of the spinal cord, either as a primary neural neoplasm or as a metastasis, and invade and destroy tracts and central gray structures (intramedullary) and (2) those arising outside the spinal cord (extramedullary), either from vertebral bodies and epidural tissues (extradural) or in the leptomeninges or roots (intradural). In a general hospital, the relative frequency of spinal tumors in these different locations is approximately 5 percent intramedullary, 40 percent intradural–extramedullary, and 55 percent extradural, the majority of the latter being metastatic cancers, as already mentioned. This percentage of extradural lesions is higher than that encountered in more specialized neurosurgical services (e.g., Elsberg’s figures of 7, 64, and 29 percent, respectively), probably because the latter do not include as many patients with extradural


Neurology_Adams

Neurology_Adams. encountered in more specialized neurosurgical services (e.g., Elsberg’s figures of 7, 64, and 29 percent, respectively), probably because the latter do not include as many patients with extradural lymphomas, metastatic carcinomas, and the like, as are seen in general hospitals.


Neurology_Adams

Neurology_Adams. Intraspinal tumors The most common primary extramedullary tumors are the neurofibromas and meningiomas, which together constitute approximately half of all intraspinal neoplasms. They are more often intradural than extradural. Neurofibromas have a predilection for the lumbar and thoracic region, whereas meningiomas are more evenly distributed over the vertical extent of the cord (Fig. 42-10). The other primary extramedullary tumors are sarcomas, vascular tumors, chordomas, and epidermoid and similar tumors, in that order of frequency.


Neurology_Adams

Neurology_Adams. Primary intramedullary tumors of the spinal cord have the same cellular origins as those arising in the brain (Chap. 30), although the proportions of particular cell types differ. Ependymomas, some of which arise from the filum terminale, make up 60 percent of the spinal cord cases and astrocytomas make up approximately 25 percent. The astrocytoma is the most common intramedullary tumor if one excludes tumors arising in the filum terminale (Fig. 42-11). Oligodendrogliomas are much less common. The remainder (approximately 15 percent) consists of a diverse group of nongliomatous tumors: lipomas, epidermoids, dermoids, teratomas, hemangiomas, hemangioblastomas, chordomas, schwannomas, and intraspinal metastatic carcinomas. The cavernous hemangioma may be a source of spontaneous hematomyelia. As indicated further on, there is a frequent association between intramedullary tumors (both gliomatous and nongliomatous) and syringomyelia. The basis of this relationship remains obscure.


Neurology_Adams

Neurology_Adams. Spinal ependymomas arise from ependymal lining of the central canal of the spinal cord. The myxopapillary type originates from clusters of ependymal cells in the filum terminale. The myxopapillary ependymoma that originates in the filum terminale causes a special syndrome referable to both lumbar roots (cauda equina) and conus. As commented in Chap. 30, a combination of asymmetric or bilateral sciatic or anterior thigh pain, sphincter difficulty, and upper motor neuron signs is typical. These spinal tumors occur in adults as often as in children, quite different from intracranial ependymomas, which are mainly childhood tumors. Although they are considered to be benign, intraspinal spread can occur and local recurrence after resection occurs in 10 percent of cases, even decades after surgery as described by Rezai and colleagues. Treatment is with surgical removal and selective radiation if there has not been gross total removal and long-term survival is the rule. The main differential


Neurology_Adams

Neurology_Adams. as described by Rezai and colleagues. Treatment is with surgical removal and selective radiation if there has not been gross total removal and long-term survival is the rule. The main differential diagnosis is a spinal schwannoma (neurofibroma).


Neurology_Adams

Neurology_Adams. Intramedullary growths invade as well as compress and distort fasciculi in the spinal cord white matter. As the cord enlarges from the tumor growing within it or is compressed by a tumor from without, the free space around the cord is eventually consumed, and the CSF below the lesion becomes isolated or loculated from the remainder of the circulating fluid above the lesion. This is marked by Froin syndrome (xanthochromia and clotting of CSF from greatly elevated protein content) and an interruption of flow of contrast medium in the subarachnoid space. The most informative diagnostic procedure is an MRI, which demonstrates both the intramedullary extent of the tumor and the effect on the surrounding subarachnoid space.


Neurology_Adams

Neurology_Adams. Secondary spinal cord tumors can also be subdivided into intramedullary and extramedullary types. Extradural metastases (carcinoma, lymphoma, myeloma) are the most common of all spinal tumors as summarized by Ropper and Ropper. They account for the largest group of patients who develop symptoms of myelopathy while being cared for in hospital and are therefore likely to be encountered in the course of neurologic consultations. Extradural metastases arise from hematogenous deposits or extend from tumors of the vertebral bodies or from a paraspinal tumor extending via the intervertebral foramina (Fig. 42-12). Secondary extramedullary tumor growths are far more often extradural than intradural. The intradural type takes the form of a meningeal carcinomatosis or lymphomatosis and the rare primary melanoma of the meninges, which are considered in Chap. 30.


Neurology_Adams

Neurology_Adams. Intramedullary metastases are not as rare as is generally believed. In a retrospective autopsy study of 627 patients with systemic cancer, Costigan and Winkelman found 153 cases with central nervous system (CNS) metastases, in 13 of which the metastases were located within the cord. In 9 of the 13 cases, the metastasis was deep in the cord, unassociated with leptomeningeal carcinomatosis; in 4 cases, the neoplasm seemed to extend from the pia. Bronchogenic carcinoma was the main source. Diagnosis is difficult but is aided greatly by MRI with gadolinium infusion; there is generally extensive contiguous edema (Fig. 42-13). Differentiation is from meningeal carcinomatosis, radiation myelopathy, and paraneoplastic necrotizing myelopathy, which is the least common of these entities. Treatment is usually ineffective unless radiation therapy is begun before paraplegia supervenes (Winkelman et al).


Neurology_Adams

Neurology_Adams. Patients with spinal cord tumors are likely to present with one of three clinical syndromes: (1) a sensorimotor spinal tract syndrome, (2) a painful radicular-spinal cord syndrome, or (3) least often, an intramedullary syringomyelic syndrome. The sensory features of these syndromes are depicted in Fig. 8-7. Pain and stiffness of the back may antedate signs of spinal cord disease or dominate the clinical picture in some cases of extramedullary tumor. The back pain is usually worse when the patient lies down or may become worse after several hours in the recumbent position and be improved by sitting up. In children, severe back pain associated with spasm of paravertebral muscles is often prominent initially; scoliosis and spastic weakness of the legs come later. Because of this somewhat unusual clinical presentation and the rarity of intraspinal lesions in childhood, spinal cord tumors in this age group may be overlooked.


Neurology_Adams

Neurology_Adams. Sensorimotor spinal tract syndrome The clinical picture is related predominantly to compression and less often to invasion and destruction of spinal cord tracts. The signs of compression consist of a combination of (1) an asymmetrical spastic weakness of the legs with thoracolumbar lesions and of the arms and legs with cervical lesions, (2) a sensory level on the trunk below which perception of pain and temperature is reduced or lost, (3) posterior column signs, and (4) a spastic bladder under weak voluntary control. The onset of the compressive symptoms is usually gradual and the course progressive over a period of weeks and months, frequently with back pain. With extradural tumors, paralysis usually develops over a period of days to several weeks, but the tempo of progression may be more rapid or more leisurely. The initial disturbance may be of motor or sensory function and the distribution may be asymmetrical. High cervical or foramen magnum lesions produce special clinical


Neurology_Adams

Neurology_Adams. be more rapid or more leisurely. The initial disturbance may be of motor or sensory function and the distribution may be asymmetrical. High cervical or foramen magnum lesions produce special clinical syndromes, as described in Chap. 3 and below. With thoracic lesions, one leg usually becomes weak and stiff before the other one. Subjective sensory symptoms of the dorsal column type (tingling paresthesias) assume similar distributions. Pain and thermal senses are more likely to be affected than tactile, vibration, and position senses. Nevertheless, the posterior columns are frequently involved as the process progresses. Initially, the sensory disturbance is contralateral to the maximum motor weakness, but a sharply defined Brown-Séquard hemicord syndrome is rarely observed. The bladder and bowel usually become paralyzed coincident with paralysis of the legs. If the compression is relieved, there is recovery from these sensory and motor symptoms, often in the reverse order of their


Neurology_Adams

Neurology_Adams. and bowel usually become paralyzed coincident with paralysis of the legs. If the compression is relieved, there is recovery from these sensory and motor symptoms, often in the reverse order of their appearance; the first part affected is the last to recover, and sensory symptoms tend to disappear before motor ones.


Neurology_Adams

Neurology_Adams. Radicular-spinal cord syndrome Here the syndrome of spinal cord compression is combined with radicular pain, that is, pain in the distribution of a sensory nerve root. The discomfort is described as knife-like or as a dull ache with superimposed sharp stabs of pain, which radiate in a distal direction, that is, away from the spine, and are intensified by coughing, sneezing, or straining. Segmental sensory changes (paresthesias, impaired perception of pinprick and touch) or motor disturbances (cramp, atrophy, fascicular twitching, and loss of tendon reflexes) and an ache in the spine, in addition to the radicular pain, are the usual manifestations. Tenderness of the spinous processes over the tumor is found by percussion in about half the patients. The segmental changes, particularly the sensory radicular ones, often precede the signs of spinal cord compression by months if the lesion is benign.


Neurology_Adams

Neurology_Adams. Intramedullary syringomyelic syndrome No single symptom is unique to the intramedullary tumors. Some degree of pain, sometimes minor, is common and is almost invariably present with tumors of the filum terminale. Ependymomas and astrocytomas, the two most common intramedullary tumors, usually give rise to a mixed sensorimotor tract syndrome. When the intramedullary tumor involves the central gray matter, a central cord, or syringomyelic syndrome may result. The main features are segmental or dissociated sensory loss, amyotrophy, early incontinence, and late corticospinal weakness. Sacral sparing of sensation may be found as described in Chap. 8 on the sensory syndromes but is of less value in distinguishing intramedullary from extramedullary lesions. A dissociation of thermal pain and tactile sensory loss over several contiguous segments on the trunk is a more dependable sign of an intramedullary lesion. Rarely, an extramedullary tumor may give rise to a syringomyelic sensory


Neurology_Adams

Neurology_Adams. and tactile sensory loss over several contiguous segments on the trunk is a more dependable sign of an intramedullary lesion. Rarely, an extramedullary tumor may give rise to a syringomyelic sensory syndrome, possibly by causing vascular insufficiency in the central portion of the cord.


Neurology_Adams

Neurology_Adams. Special spinal syndromes Unusual clinical syndromes may be found in patients with tumors in the region of the foramen magnum, as discussed in Chap. 3. They produce quadriparesis with pain in the back of the head and stiff neck, weakness and atrophy of the hands and dorsal neck muscles, marked imbalance, and variable sensory changes or, if they spread intracranially, there may be signs of cerebellar and lower cranial nerve involvement. Slowly growing tumors in this region, such as meningiomas, characteristically produce an “around the clock” progression of weakness beginning in one limb and proceeding to the adjacent one in a clockwise or counterclockwise direction. Lesions at the level of the lowermost thoracic and the first lumbar vertebrae may result in mixed cauda equina and spinal cord symptoms. A Babinski sign indicates that the spinal cord is involved above the fifth lumbar segment.


Neurology_Adams

Neurology_Adams. Lesions of the cauda equina alone, always difficult to separate from those of the lumbosacral plexuses and multiple nerves, are usually attended in the early stages by sciatic and other root pain and lumbar ache, which are variously combined with a bilaterally asymmetrical, atrophic, areflexic paralysis, radicular sensory loss, and sphincteric disorder. These must be distinguished from lesions of the conus medullaris (lower sacral segments of the spinal cord), in which there are early disturbances of the bladder and bowel (urinary retention and constipation), back pain, symmetrical hypesthesia or anesthesia over the sacral dermatomes, a lax anal sphincter with loss of anal and bulbocavernosus reflexes, impotence, and sometimes weakness of leg muscles. Sensory abnormalities may precede motor and reflex changes by many months. Very rarely, for unclear reasons, tumors of the thoracolumbar cord (intramedullary, as a rule) are associated with markedly elevated spinal fluid protein and


Neurology_Adams

Neurology_Adams. motor and reflex changes by many months. Very rarely, for unclear reasons, tumors of the thoracolumbar cord (intramedullary, as a rule) are associated with markedly elevated spinal fluid protein and hydrocephalus; these respond to shunting and removal of the spinal tumor (Feldman et al). Less often, these tumors are associated with a pseudotumor cerebri syndrome.


Neurology_Adams

Neurology_Adams. Several problems arise in the diagnosis of spinal cord tumors in addition to several previously mentioned. In the early stages, neoplastic compression or invasion of the cord must be distinguished from other diseases that cause pain over certain segments of the body, for example, diseases affecting the gallbladder, pancreas, kidney, stomach and intestinal tract, and pleura. Localization of the pain to a dermatome; its intensification by sneezing, coughing, and straining, and sometimes by recumbency; and the finding of segmental sensory changes and minor alterations of motor, reflex, or sensory function in the legs will usually provide the clues to the presence of a spinal cord–radicular lesion. MRI will settle the diagnosis in most instances. The pain of tumor or blood clot in the retroperitoneal space may cause an orthostatic and nocturnal back pain that is similar to that of spinal tumor.


Neurology_Adams

Neurology_Adams. There is then the problem of locating the segmental level of the lesion. At first, the sensory and motor deficits may be most pronounced in those parts of the body farthest removed from the lesion, that is, in the feet or lumbosacral segments. Later the levels of the sensory and motor deficits ascend, but they may still be at a level several segments below the lesion. In determining the level of the lesion, the location of back pain, root pain, and atrophic paralysis are of greater help than the upper level of hypoalgesia.


Neurology_Adams

Neurology_Adams. Once vertebral and segmental levels of the lesion are settled, there remains the necessity of determining whether the lesion is extradural, intradural–extramedullary, or intramedullary and whether it is neoplastic. If there is a visible or palpable spinal deformity or radiographic evidence of vertebral destruction, one may confidently assume an extradural localization. Even without these changes, one still suspects an extradural lesion if root pain developed early and is bilateral, if pain and aching in the spine are prominent and percussion tenderness is marked, if motor symptoms below the lesion preceded sensory ones, and if sphincter disturbances were late. However, to distinguish between intradural–extramedullary lesions and intramedullary lesions on clinical grounds alone is often difficult. The findings of segmental amyotrophy and sensory loss of dissociated type (loss of pain and temperature and preservation of tactile sensation) point to an intramedullary lesion.


Neurology_Adams

Neurology_Adams. Extradural tumors, both primary and secondary, must be differentiated from cervical spondylosis, tuberculous granuloma, sarcoidosis, arteriovenous malformations of the cord, spinal dural fistulas, and certain chronic pyogenic or fungal granulomatous lesions, as well as from lipomas in patients receiving corticosteroids for prolonged periods and from the necrotizing myelopathy associated with occult tumors or occurring independently of them. A number of rarer conditions of the vertebral bodies such as bone cysts, chondromas, eosinophilic granuloma, chordomas, and giant cell tumors must also be considered; these are summarized by Ropper and coworkers (2011). In the thoracic region, a ruptured disc or eventration of the cord through a dural tear is always a possibility. In the region of the lower back, that is, over the cauda equina, one must also distinguish between tumor and protruded inter-vertebral disc. Here, an extradural tumor may produce mainly sciatic and low back pain with


Neurology_Adams

Neurology_Adams. the lower back, that is, over the cauda equina, one must also distinguish between tumor and protruded inter-vertebral disc. Here, an extradural tumor may produce mainly sciatic and low back pain with little or no motor, sensory, reflex, or sphincteric disturbances. With intradural–extramedullary lesions, the important diagnostic considerations are meningioma, neurofibroma, meningeal carcinomatosis, cholesteatoma, and teratomatous cyst, a meningomyelitic process, or adhesive arachnoiditis. Intramedullary lesions are usually gliomas, ependymomas, or vascular malformations or, in the context of a known carcinoma, intramedullary metastases. The definition of vascular malformations by means of selective spinal angiography was discussed in an earlier section. Normal protein in the CSF and negative MRI effectively exclude an intramedullary tumor.


Neurology_Adams

Neurology_Adams. The main consideration in the management of epidural metastases is the need for early diagnosis, at a stage when only back pain is present and before neurologic symptoms and signs have appeared. Once these signs appear, especially sphincter disturbances, the results of treatment are less successful but may still result in good limb and bladder function. Epidural growths of carcinoma and lymphoma have been typically managed by administration of high to moderate doses of corticosteroids and radiation of the region of tumor although surgical options exist and provide faster decompression and the opportunity for stabilization of the spinal column. The choice of surgery or stereotactic radiation is complex, partly stylistic, and dependent on the likelihood of survival as noted below, and possibly by the radiosensitivity of the tumor and as summarized by Ropper and Ropper. Either treatment may be supplemented by endocrine therapy (for carcinoma of breast and prostate), and of antineoplastic


Neurology_Adams

Neurology_Adams. by the radiosensitivity of the tumor and as summarized by Ropper and Ropper. Either treatment may be supplemented by endocrine therapy (for carcinoma of breast and prostate), and of antineoplastic drugs (for certain lymphomas and myelomas. Pain relief is sometimes difficult to attain and requires narcotics. Gilbert and associates presented evidence that patients who receive high-dose corticosteroids (16 to 60 mg of dexamethasone) and fractionated radiation (500 cGy on each of the first 3 days and then spaced radiation up to 3,000 cGy) do as well as those who have surgical decompression. However, a comparison of five different radiation programs by Nieder and colleagues suggested there is little difference between them. An often cited review of the radiotherapy options was given by Gerszten and colleagues in 2009 but the techniques change so rapidly that it is difficult to determine and compare outcomes. The issue of radiosensitivity of any particular tumor has become a relative one as


Neurology_Adams

Neurology_Adams. and colleagues in 2009 but the techniques change so rapidly that it is difficult to determine and compare outcomes. The issue of radiosensitivity of any particular tumor has become a relative one as high doses of focal radiation are being delivered in one or a few fractions by special (stereotactic) techniques.


Neurology_Adams

Neurology_Adams. Laminectomy and decompression are appropriate to prevent irreversible compressive effects and infarction of the cord for rapidly growing tumors that have caused recent and severe loss of function below the level of compression. Cases that have been allowed to progress can be operated on if paraplegia has occurred within one or perhaps two days or less and the overall state of the patient’s cancer makes survival likely for at least several weeks. An often cited trial comparing radiation and surgery by Patchell and colleagues suggested that ambulation is preserved for a longer time with surgery. All these comments, and the trial, refer to compression of the cord at a single level. If the maximal safe radiation dosage had previously been applied to the spinal column, or the diagnosis can only be made from tissue obtained from the site of spinal compression, surgical palliation is usually undertaken.


Neurology_Adams

Neurology_Adams. Intradural–extramedullary tumors should generally be removed if this can be accomplished safely, and this applies to benign extradural tumors that are symptomatic as well. Laminectomy, decompression, excision in isolated cases, and radiotherapy constitute the treatment of intramedullary gliomas. Such patients may improve and lead useful lives for a decade or longer. Constantini and colleagues, based on a large experience with intramedullary lesions, mainly gliomas in children and young adults, recommend a radical excision of the tumor, but this approach has not been subjected to a trial. Other Causes of Spinal Cord Compression


Neurology_Adams

Neurology_Adams. Other Causes of Spinal Cord Compression Epidural fat deposition (epidural lipomatosis) with spinal cord compression occurs in Cushing disease and after the long-term use of corticosteroids, but also in the absence of these disorders. The clinical picture may suggest discogenic disease (Lipson et al). Copious amounts of normal adipose tissue are found at laminectomy and removal of this tissue is curative. Lowering the dose of steroid and caloric restriction may help mobilize the fat and relieve the symptoms. An intra-spinal lipoma is also a component of the developmentally tethered cord, but in this process the essential problem is a conus medullaris myelopathy from stretching of the cord, rather than compression (see Chap. 37 and Thomas and Miller.)


Neurology_Adams

Neurology_Adams. Chap. 37 and Thomas and Miller.) Arachnoid diverticula—intraor extradural outpouchings from the posterior nerve root—are rare causes of a radicular-spinal cord syndrome, first described by Bechterew in 1893. They tend to occur in the thoracic or lumbosacral regions. The symptoms, in order of decreasing frequency, are pain, radicular weakness and sensory disorder, gait disorder, and sphincteric disturbances, as described by Cilluffo et al. The frequent association of arachnoid diverticula with osteoporosis, ankylosing spondylitis, and arachnoiditis makes it difficult to interpret the role of the diverticula themselves. Surgical obliteration of the pouches has yielded unpredictable results. They have attained clinical importance more often as the source of spontaneous CSF leaks and a low-pressure syndrome (see Chap. 29).


Neurology_Adams

Neurology_Adams. Spinal cord compression with paraplegia may be caused by extramedullary hematopoiesis in cases of myelosclerosis, thalassemia, cyanotic heart disease, myelogenous leukemia, sideropenic anemia, and polycythemia vera. A similar phenomenon occurs with ossification of the posterior longitudinal ligament, as described earlier. Solitary osteochondromas of vertebral bodies and multiple exostoses of hereditary type are other reported causes of spinal cord compression. In the case reported by Buur and Morch, the clinical syndrome was one of pure spastic paraparesis of several months’ progression. Lathyrism (See Also Chap. 41) From the interesting historical review of Dastur, one learns that this disease was known to Hippocrates, Pliny, and Galen in Europe, to Avicenna in the Middle East, and to the ancient Hindus. The term lathyrism was applied by Cantani, in Italy, because of its recognized relationship to the consumption of Lathyrus sativus (chickling vetch, vetch pea, or grass pea).


Neurology_Adams

Neurology_Adams. The disease is still common in some parts of India and Africa. In these districts, during periods of famine when wheat and other grains are in short supply, the diet may for months consist of flour made of the grass pea. In individuals so exposed, a gradual weakening of the legs accompanied by spasticity and cramps occurs. Paresthesias, numbness, formication in the legs, and frequency and urgency of micturition, erectile dysfunction, and sphincteric spasms are added. The upper extremities may exhibit coarse tremors and involuntary movements. These symptoms, once established, are more or less permanent but not progressive, and most of the patients live out their natural life span.


Neurology_Adams

Neurology_Adams. Only two reports on the neuropathology of lathyrism were known to Dastur, one by Buzzard and Greenfield in England, the other by Filiminoff in Russia. Both of their patients had been in a stationary paraplegic state for years. Greenfield noted a loss of ascending and descending tracts in the spinal cord, particularly the corticospinal and direct spinocerebellar tracts. Filiminoff observed a loss of myelinated fibers in the lateral and posterior columns. Unlike the cases of Spencer and colleagues, there had been a loss of pain and thermal sensation in the upper extremities. The larger Betz cells had disappeared, while anterior horn cells were unaffected. Gliosis and thickening of blood vessels was seen in the degenerated tracts.


Neurology_Adams

Neurology_Adams. The toxic nature of this disease, long suspected, was confirmed by Spencer and colleagues. They extracted a neuroexcitatory amino acid, beta-N-oxalylaminoalanine (BOAA), from grass peas and were able to induce corticospinal dysfunction in monkeys by giving this substance with a nutritious diet. Subsequently, Hugon and coworkers produced a primate model of lathyrism by feeding monkeys a diet of L. sativus in addition to an alcoholic extract of this legume. These findings tend to negate the importance of several other factors that had been thought to be causative, namely, malnutrition, ergot contamination, and toxins derived from Vicia sativa, the common vetch that grows alongside the lathyrus species. The African acute spastic paraplegia called konzo has a similar toxic pathogenesis; it is caused by cyanide-like compounds in flour made from cassava.


Neurology_Adams

Neurology_Adams. The African acute spastic paraplegia called konzo has a similar toxic pathogenesis; it is caused by cyanide-like compounds in flour made from cassava. These are described in Chap. 37 but should be considered in cases of chronic and progressive syndromes of the cauda equina and conus medullaris. Familial Spastic Paraplegia (See Chap. 38)


Neurology_Adams

Neurology_Adams. Familial Spastic Paraplegia (See Chap. 38) There are several familial forms of progressive spastic paraplegia, some beginning in childhood, others in adult life. The pattern of inheritance in almost all our adult cases has been autosomal dominant. A lack of sensory symptoms and signs and sparing of sphincteric function until late in the illness are important diagnostic features. A number of adult cases are “complicated” in the sense that the spastic paraplegia is associated with cerebellar ataxia or dementia. By contrast, primary lateral sclerosis, a sporadic form of degenerative disease of the motor system, is characterized by a pure spastic paraplegia and bulbar spastic palsy either initially or with progression, the result of changes that are confined to the corticospinal pathways. These disorders are discussed extensively with the heredodegenerative diseases in Chap. 38, and the myelopathy associated with adrenoleukodystrophy, in Chap. 36.


Neurology_Adams

Neurology_Adams. This syndrome is most often attributable to developmental syringomyelia, that is, a central cavitation of the spinal cord of undetermined cause, but a similar clinical syndrome may be observed in association with other pathologic states such as intramedullary cord tumors, traumatic myelopathy, postradiation myelopathy, infarction (myelomalacia), bleeding (hematomyelia), and, rarely, with extramedullary tumors, cervical spondylosis, spinal arachnoiditis, and cervical necrotizing myelitis. Syringomyelia (Syrinx) (See Also Chap. 37)


Neurology_Adams

Neurology_Adams. Syringomyelia (from the Greek syrinx, “pipe” or “tube”) is defined as a chronic progressive degenerative or developmental disorder of the spinal cord, characterized clinically by painless weakness and wasting of the hands and arms (brachial amyotrophy) and segmental sensory loss of dissociated type (loss of thermal and painful sensation with sparing of tactile, joint position, and vibratory sense, as described later). The cause is a cavitation of the central parts of the spinal cord, usually in the cervical region, but extending upward in some cases into the medulla and pons (syringobulbia) or downward into the thoracic and even into the lumbar segments. Frequently, there are associated developmental abnormalities of the vertebral column (thoracic scoliosis, fusion of vertebrae, or Klippel-Feil anomaly), of the base of the skull (platybasia and basilar invagination), and there is a special relationship to developmental deformations of the cerebellum and brainstem (particularly type I


Neurology_Adams

Neurology_Adams. anomaly), of the base of the skull (platybasia and basilar invagination), and there is a special relationship to developmental deformations of the cerebellum and brainstem (particularly type I Chiari malformation). A large proportion of cases of developmental syringomyelia have type I Chiari malformation, consisting of a descent of cerebellar tonsils below the foramen magnum as discussed in


Neurology_Adams

Neurology_Adams. Chap. 37. There is also a group of less frequent but well-described syringomyelias that derives from the acquired processes mentioned earlier such as intramedullary tumor (astrocytoma, hemangioblastoma, ependymoma) and from preceding traumatic or hemorrhagic necrosis of the spinal cord. Wider experience with the pathology of developmental syringomyelia has led to the following classification, modified from Barnett and colleagues that unfortunately creates some confusion because it simulates the Roman numeral classification of the Chiari malformations, with which it is sometimes allied: Type I. Syringomyelia with obstruction of the foramen magnum and dilatation of the central canal (developmental type) A. With type I Chiari malformation B. With other obstructive lesions of the foramen magnum, usually bony anomalies Type II. Syringomyelia without obstruction of the foramen magnum (idiopathic developmental type)


Neurology_Adams

Neurology_Adams. B. With other obstructive lesions of the foramen magnum, usually bony anomalies Type II. Syringomyelia without obstruction of the foramen magnum (idiopathic developmental type) Type III. Syringomyelia with other diseases of the spinal cord (acquired types) A. Spinal cord tumors (usually intramedullary, especially hemangioblastoma) B. Traumatic myelopathy C. Spinal arachnoiditis and pachymeningitis D. Secondary myelomalacia from cord compression (tumor, spondylosis), infarction, hematomyelia Type IV. Pure hydromyelia (developmental dilatation of the central canal), with or without hydrocephalus


Neurology_Adams

Neurology_Adams. Historical note Although pathologic cavitation of the spinal cord was recognized as early as the sixteenth century, the term syringomyelia was first used to describe this process in 1827 by Ollivier d’Angers (cited by Ballantine et al). Later, following recognition of the central canal as a normal structure, it was assumed by Virchow (1863) and by Leyden (1876) that cavitation of the spinal cord had its origin in an abnormal expansion of the central canal, and they renamed the process hydromyelia. Cavities in the central portions of the spinal cord, unconnected with the central canal, were recognized by Hallopeau (1870); Simon suggested in 1875 that the term syringomyelia be reserved for such cavities and that the term hydromyelia be restricted to simple dilatation of the central canal. Thus, a century ago, the stage was set for an argument about pathogenesis that has not been settled to the present day.


Neurology_Adams

Neurology_Adams. The clinical picture varies in the four pathologic types previously listed, the differences depending not only on the extent of the syrinx but also on the associated pathologic changes, particularly those related to the Chiari malformation. When there is no Chiari malformation, the association of syringomyelia with an intramedullary tumor (type III), particularly ependymoma, should be suspected; there is a disassociated sensorimotor abnormality extending over many segments of the body. Most cases of syrinx cavity that we have seen in adults have been from ependymoma. With von Hippel-Lindau disease, the diagnosis hinges on the finding of the characteristic hereditary hemangioblastoma in the syrinx and retinal and cerebellar vascular malformations. In posttraumatic cases, necrosis of the spinal cord that has been stable for months or years begins to cause pain and spreading sensory or motor loss, recognizable only in segments above the original lesion (Schurch et al). This occurred in


Neurology_Adams

Neurology_Adams. cord that has been stable for months or years begins to cause pain and spreading sensory or motor loss, recognizable only in segments above the original lesion (Schurch et al). This occurred in approximately 3 percent of the traumatic myelopathy cases of Rossier and coworkers, more often in quadriplegics than in paraplegics. The posttraumatic syrinx is not as well defined anatomically as the usual forms of syringomyelia but consists instead of several contiguous areas of glia-lined myelomalacia with differing degrees of cavitation. In some instances of progressive spinal cord symptoms occurring several years after spinal surgery, the lesion has proved to be one of arachnoiditis and cord atrophy and not a syrinx (Avrahami et al).


Neurology_Adams

Neurology_Adams. In the typical type I developmental syrinx (idiopathic, Chiari-associated developmental syringomyelia), symptoms usually begin in early adult life (20 to 40 years). Males and females are equally affected. Rarely, some abnormality is noted at birth, but usually the first symptom appears in late childhood or adolescence. The onset is usually insidious and the course irregularly progressive. In many instances, the symptoms or signs are discovered accidentally, for example, as a result of painless burn or atrophy of the hand, and the patient cannot say when the disease began. Rarely, there is an almost apoplectic onset or worsening; there are cases on record of an aggravation of old symptoms or the appearance of new symptoms after a violent strain or paroxysm of coughing. Trauma is a less certain precipitant. Once the disease is recognized, some patients remain much the same for years, even decades, but more often there is intermittent progression to the point of being chair-bound within


Neurology_Adams

Neurology_Adams. precipitant. Once the disease is recognized, some patients remain much the same for years, even decades, but more often there is intermittent progression to the point of being chair-bound within 5 to 20 years. This extremely variable course makes it difficult to evaluate therapy.


Neurology_Adams

Neurology_Adams. The precise clinical picture at any given point in the evolution of the disease depends on the cross-sectional and longitudinal extent of the syrinx, but certain clinical features are so common that the diagnosis can hardly be made without them. These traditionally cited elements are (1) segmental weakness and atrophy of the hands and arms, (2) loss of some or all tendon reflexes in the arms, and (3) segmental anesthesia of a dissociated type (loss of pain and thermal sense and preservation of the sense of touch) over the neck, shoulders, and arms. The last of these leads to one of the most characteristic features of syringomyelia: painless injuries and burns of the hands. Finally, there are in cases of extensive cavitation weakness and ataxia of the legs from involvement of the corticospinal tracts (possibly at their decussation) and posterior columns in the cervical region.


Neurology_Adams

Neurology_Adams. Kyphoscoliosis is added in many of the cases and in nearly one-quarter of them there is an overt cervicooccipital malformation (short neck, low hairline, odd posture of the head and neck, fused or missing cervical vertebrae, that is, Klippel-Feil abnormality). The particular muscle groups that are affected on the two sides may vary. Exceptionally, motor function is spared, and the segmental dissociated sensory loss and/or pain are the only marks of the disease. In a few of the cases, especially those with the Chiari malformation, the reflexes in the arms are preserved or even hyperactive, as might be expected with upper rather than lower motor neuron involvement. Or the shoulder muscles may be atrophic and the hands spastic. In the lower extremities the weakness, if present, is of a spastic (corticospinal) type.


Neurology_Adams

Neurology_Adams. The characteristic segmental sensory dissociation is usually bilateral but a unilateral pattern affecting only one hand and arm is not unknown, and this is true of the amyotrophy as well. The sensory loss is distributed in a “cape” or hemicape pattern, often extending to back of the head or the face and onto the trunk. Although tactile sensation is usually preserved, there are cases in which it is impaired, usually in the region of the densest analgesia over the trunk or hand. Exceptionally there is no sensory loss in the presence of amyotrophy, and cases have been recorded in which only a hydrocephalus and hydromyelia were present with spastic paraparesis. If tactile sensation is affected in the arms, joint position and vibratory sense tend also to be impaired. In the lower extremities and over the abdomen there may be some loss of pain and thermal sensation proximally, but more often there is a loss of vibratory and position sense, which is indicative of a posterior column lesion


Neurology_Adams

Neurology_Adams. and over the abdomen there may be some loss of pain and thermal sensation proximally, but more often there is a loss of vibratory and position sense, which is indicative of a posterior column lesion and is the basis of ataxia. A Horner syndrome may result from ipsilateral involvement of the intermediolateral cell column at the C8, T1, and T2 levels.


Neurology_Adams

Neurology_Adams. Pain has been a symptom in about half of our patients with developmental types of syringomyelia. The pain is usually unilateral or more marked on one side of the neck, shoulder, and arm; it is of a burning, aching quality, mostly in or at the border of areas of sensory impairment. In a few patients, it involves the face or trunk. An aching pain at the base of the skull or posterior cervical region that is intensified by coughing, sneezing, or stooping (brief exertional pain) is often present, but, as Logue and Edwards point out, pain of this type may be a feature of Chiari malformation without syringomyelia and in that case is probably attributable to compression or stretching of cervical roots.


Neurology_Adams

Neurology_Adams. Syringobulbia is the lower brainstem equivalent of syringomyelia. Usually the two coexist and the brainstem cavity is simply an extension of one in the upper cord, but occasionally the bulbar manifestations precede the spinal ones or, rarely, occur independently. The glial cleft or cavity is located most often in the lateral tegmentum of the medulla, but it may extend into the pons and, rarely, even higher. The symptoms and signs are characteristically unilateral and consist of nystagmus, analgesia, and thermoanesthesia of the face (numbness); wasting and weakness of the tongue (dysarthria); and palatal and vocal cord paralysis (dysphagia and hoarseness). Diplopia, episodic vertigo, trigeminal pain or facial sensory loss, and persistent hiccough are less common symptoms. For understandable reasons, the diagnosis of brainstem MS is often raised. The clinical and pathologic features of syringobulbia have been described in great detail by Jonesco-Sisesti.


Neurology_Adams

Neurology_Adams. When a Chiari malformation is associated with syringomyelia and syringobulbia, it may be difficult to separate the effects of the two disorders. A typical example is shown in Fig. 37-4. Clinical features that favor the predominance of Chiari malformation are nystagmus, cerebellar ataxia, exertional head and neck pain, prominent corticospinal and sensory tract involvement in the lower extremities, hydrocephalus, and craniocervical malformations. In syringomyelia without a Chiari malformation but with some other type of obstructive lesion at the foramen magnum, the clinical picture is much the same, and the nature of the foramen magnum lesion can be determined only by MRI or surgical exploration.


Neurology_Adams

Neurology_Adams. This refers to a dilatation of the central canal that is distinct from developmental syringomyelia. The relationship between hydromyelia and syringomyelia has been the source of endless debate, in part the result of the lack of a coherent pathophysiologic explanation for either process. At least one hypothesis for the origin of syringomyelia includes an initial dilatation of the central canal (see later). Our impression is that a relatively nonprogressive, well-defined, cylindrical enlargement of the central canal over a few thoracic segments is a frequent enough occurrence in the absence of clinical changes that it represents an independent entity. In the few cases of symptomatic hydromyelia that have come to our attention, there had usually been a long-standing congenital hydrocephalus complicated years later by progressive weakness and atrophy of the shoulders and the muscles of the arms and hands. More often, there is no associated obstruction at the upper cord and no


Neurology_Adams

Neurology_Adams. complicated years later by progressive weakness and atrophy of the shoulders and the muscles of the arms and hands. More often, there is no associated obstruction at the upper cord and no hydrocephalus for which reason it is our impression that most cases are benign and relatively nonprogressive. Proof of the existence of pure hydromyelia in the past has been based on necropsy demonstration of an enormously widened central canal, with or without hydrocephalus. Now, hydromyelia is easily diagnosable by MRI and numerous asymptomatic cases are being discovered, causing unnecessary concern and neurologic consultation.


Neurology_Adams

Neurology_Adams. Pathogenesis of Type I Syringomyelia Experimental work in animals has indicated that there is a normal flow of CSF from the spinal subarachnoid space through perivascular spaces to the parenchyma of the cord and possibly into the central canal. It has been suggested that impediments to flow might explain dilatation of the central canal, or the creation of a parallel or attached syrinx cavity.


Neurology_Adams

Neurology_Adams. One theory of the pathogenesis of developmental syringomyelia, of which Gardner was the main advocate, is that the normal flow of CSF from the central canal to the fourth ventricle and its outlets is prevented by an obstruction of the foramina of Luschka and Magendie. As a result, a pulse wave of CSF pressure that is generated by systolic pulsations of the choroid plexuses is transmitted into the cord from the fourth ventricle through the central canal. According to this theory, the syrinx consists essentially of a greatly dilated central canal with a diverticulum that ramifies from the central canal and dissects along gray matter and adjacent fiber tracts. The frequency with which syringomyelia is linked to malformations at the craniocervical junction, that is, to Chiari and other lesions that could interfere with normal flow of CSF, lends credence to this theory. There are many instances, however, in which


Neurology_Adams

Neurology_Adams. Gardner’s hydrodynamic theory could not explain syringomyelia. In some cases, for example, the foramina of Luschka and Magendie are found to be patent, and other abnormalities of the posterior fossa or foramen magnum that block CSF flow are not in evidence. Furthermore, in many cases, including several we have inspected, serial histologic sections have failed to demonstrate a connection between the fourth ventricle and the syrinx in the spinal cord or of a widening of the central canal above the syrinx (see also Hughes). Gardner’s theory has been questioned on other grounds. Ball and Dayan calculated the pulse-pressure wave transmitted into the cord to be of such low amplitude as to be unlikely to produce a syrinx. In their view, the CSF around the cervical cord, under increased pressure during strain or physical effort because of subarachnoid obstruction at the craniocervical junction, tracks into the spinal cord along the Virchow-Robin spaces or other subpial channels. Over a


Neurology_Adams

Neurology_Adams. during strain or physical effort because of subarachnoid obstruction at the craniocervical junction, tracks into the spinal cord along the Virchow-Robin spaces or other subpial channels. Over a prolonged period, abetted perhaps by traumatic lesions, small pools of fluid coalesce to form a syrinx. In their view, originally the syrinx forms independently of the central canal, but eventually the two may become connected, allowing secondary enlargement of the canal (hydromyelia ex vacuo). The findings of Heiss and colleagues lend support to this theory. They found that progression of syringomyelia is produced by the compressive effect of the cerebellar tonsils, which partially occlude the subarachnoid space at the foramen magnum and create pressure waves that compress the spinal cord from without and not from within; the pressure waves propagate syrinx fluid caudally with each heartbeat. This hardly exhausts the list of hypotheses that have been offered over the years but none of them has