10.14639/0392-100X-N2487
Objective. Vocal fold polyps (VFPs) are the most common benign laryngeal lesions that require surgery and are routinely managed by microlaryngoscopy (MLS) under general anaesthesia. Prior to introduction of MLS, VFPs were removed using indirect laryngoscopic surgery (ILS) in local anaesthesia, a procedure that required substantial surgical skill to operate with an unmagnified mirror view of the larynx. With the adoption of wireless endoscopy equipment and personal computers, we tried to simplify this technique so that it can be easily performed in the office. This study aimed to assess the effectiveness of ILS by comparing voice outcomes with MLS. Materials and methods. ILS and MLS were performed in six patients each. Treatment outcomes were measured using a voice self-assessment and objective acoustic analysis. The total cost of both procedures was calculated.Results. Both techniques allowed successful removal of VFPs in all patients, without significant intergroup differences in voice outcomes. The cost of ILS was significantly lower. Conclusions. Despite the pilot nature of the study and the small sample size, our data indicate the potential value of this technique which, considering its simplicity and economic value could be used as an alternative to MLS in carefully selected patients.
text/xml
1827-675X
2487
en
Zoran Milutinovic
http://creativecommons.org/licenses/by-nc-nd/4.0
ACTA Otorhinolaryngologica Italica
office-based laryngeal surgery
Indirect laryngeal surgery of vocal fold polyps: A dying or evolving art?
Text.Serial.Journal
https://www.actaitalica.it/
43
Clinical techniques and technologies
2023-07-28
2023-01-22
2023-12-19
2023-12-19
424-429
1
Zoran Milutinovic
2023/07/28
10.14639/0392-100X-N2487
424
Chair of Otorhinolaryngology with Maxillofacial Surgery, Faculty of Medicine, University of Belgrade, Belgrade, Serbia
1827-675X
office-based laryngeal surgery
en
429
Indirect laryngeal surgery of vocal fold polyps: A dying or evolving art?
https://www.actaitalica.it/article/download/2487/1031
43
ACTA OTORHINOLARYNGOLOGICA ITALICA 2023;43:424-429; doi: 10.14639/0392-100X-N2487




Clinical techniques and technologies


Indirect laryngeal surgery of vocal fold polyps:
a dying or evolving art?
Chirurgia laringea indiretta dei polipi delle corde vocali:
un’arte in via di estinzione o in evoluzione?
Ognjen Cukic1, Dejan Radaljac2, Nenad Arsovic3,4, Milan Jovanovic2,4, Zoran Milutinovic4
1
 Clinic for Otorhinolaryngology, Military Medical Academy, Belgrade, Serbia; 2 Department of Otorhinolaryngology with Maxillofacial
Surgery, Clinical Hospital Center Zemun, Zemun, Serbia; 3 Clinic for Otorhinolaryngology and Maxillofacial Surgery, University Clinical
Center of Serbia, Belgrade, Serbia; 4 Chair of Otorhinolaryngology with Maxillofacial Surgery, Faculty of Medicine, University
of Belgrade, Belgrade, Serbia


SUMMARY
Objective. Vocal fold polyps (VFPs) are the most common benign laryngeal lesions that
require surgery and are routinely managed by microlaryngoscopy (MLS) under general an-
aesthesia. Prior to introduction of MLS, VFPs were removed using indirect laryngoscopic
surgery (ILS) in local anaesthesia, a procedure that required substantial surgical skill to
operate with an unmagnified mirror view of the larynx. With the adoption of wireless en-
doscopy equipment and personal computers, we tried to simplify this technique so that it
can be easily performed in the office. This study aimed to assess the effectiveness of ILS by
comparing voice outcomes with MLS.
Materials and methods. ILS and MLS were performed in six patients each. Treatment
outcomes were measured using a voice self-assessment and objective acoustic analysis. The
total cost of both procedures was calculated.
Results. Both techniques allowed successful removal of VFPs in all patients, without sig-
nificant intergroup differences in voice outcomes. The cost of ILS was significantly lower.
Conclusions. Despite the pilot nature of the study and the small sample size, our data in-
dicate the potential value of this technique which, considering its simplicity and economic
value could be used as an alternative to MLS in carefully selected patients.                      Received: January 22, 2023
                                                                                                  Accepted: March 6, 2023
KEY WORDS: indirect laryngoscopy, microlaryngoscopy, vocal fold polyps, office-based              Published online: July 28, 2023
laryngeal surgery
                                                                                                  Correspondence
RIASSUNTO                                                                                         Ognjen Cukic
Obiettivo. I polipi delle corde vocali (VFPs) rappresentano le più comuni lesioni laringee        Clinic for Otorhinolaryngology, Military Medical
benigne e sono generalmente trattati in microlaringoscopia diretta (MLS) in anestesia ge-         Academy, Crnotravska 17, 11000, Belgrade, Serbia
                                                                                                  Tel. +381 11 360 87 87
nerale. Prima dell’avvento di tale procedura, i VFPs erano rimossi tramite chirurgia in
                                                                                                  E-mail: ognjen.cukic.bg@gmail.com
laringoscopia indiretta (ILS) in anestesia locale. Abbiamo cercato pertanto di semplificare
la ILS con l’aiuto di strumenti endoscopici wireless e di computer, in modo da renderla
facilmente eseguibile in ambulatorio. Obiettivo del presente studio è di testare l’efficacia        How to cite this article: Cukic O, Radaljac D,
della ILS.                                                                                          Arsovic N, et al. Indirect laryngeal surgery of
Materiali e metodi. ILS e MLS sono state eseguite in 6 pazienti ciascuna. I risultati del trat-     vocal fold polyps: a dying or evolving art? Acta
tamento sono stati misurati attraverso autovalutazione vocale ed analisi acustica oggettiva.        Otorhinolaryngol Ital 2023;43:424-429. https://
                                                                                                    doi.org/10.14639/0392-100X-N2487
Sono stati inoltre calcolati i costi di ILS e MLS.
Risultati. Entrambe le tecniche si sono confermate efficaci nella rimozione di VFPs in tutti
                                                                                                  © Società Italiana di Otorinolaringoiatria
i pazienti in assenza di alterazioni vocali significative. I costi della ILS si sono dimostrati   e Chirurgia Cervico-Facciale
significativamente inferiori.
Conclusioni. Nonostante il piccolo campione di pazienti, i nostri dati confermano il poten-                      OPEN ACCESS
ziale valore della ILS. Alla luce della sua semplicità e della convenienza economica, la ILS
potrebbe essere utilizzata come alternativa alla MLS in pazienti attentamente selezionati.        This is an open access article distributed in accordance with
                                                                                                  the CC-BY-NC-ND (Creative Commons Attribution-Non-
KEY WORDS: laringoscopia indiretta, microlaringoscopia, polipi delle corde vocali,                Commercial-NoDerivatives 4.0 International) license. The
                                                                                                  article can be used by giving appropriate credit and mentio-
chirurgia laringea ambulatoriale                                                                  ning the license, but only for non-commercial purposes and
                                                                                                  only in the original version. For further information: https://
                                                                                                  creativecommons.org/licenses/by-nc-nd/4.0/deed.en




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Introduction                                                     was based on the patients’ tolerance of the mirror laryn-
                                                                 goscopy/laryngovideostroboscopic examination on the
Benign vocal fold lesions are the most common organic
                                                                 initial visit. Patients with good compliance were offered
cause of long-standing hoarseness, with approximately
                                                                 to undergo either ILS or MLS based on their preference.
50% of dysphonic patients showing some form of this pa-
                                                                 The patients with severe gagging were automatically trans-
thology. In clinical practice, vocal fold polyps (VFP) are
                                                                 ferred to the MLS group. Patients with more extensive or
the most frequently encountered form of these lesions and
                                                                 submucosal vocal fold pathology, which required delicate
usually require surgical treatment 1. The concept of indi-
                                                                 bimanual dissection under an operating microscope, or
rect laryngeal surgery (ILS) using the transoral route in an
                                                                 with lesions clinically suspicious for malignancy, were not
awake patient was established in Berlin in 1861 when Vic-
                                                                 included in the study.
tor von Bruns performed VFP removal in his brother us-
ing mirror laryngoscopy with a specially designed curved
                                                                 Surgery
instrument 2. The exposure of the larynx in ILS was greatly
                                                                 The ILS was performed using Brunnings curved cup for-
improved by magnifying the laryngeal mirror view with the
                                                                 ceps for indirect laryngeal operations (Karl Storz 777910,
operating microscope 3. However, transoral manipulation
                                                                 775100, and 775600; Tuttlingen, Germany) under the visual
with a long, curved laryngeal forceps under mirror vision
                                                                 guidance provided by a rigid 70° telelaryngoscope (Fig. 1A).
and without directly visualising the tip of the instrument
                                                                 For additional magnification and documentation purposes, a
required a certain degree of manual dexterity. This was ini-
                                                                 wireless camera (Firefly DE1250; Firefly Global, Belmont,
tially ameliorated by substituting the laryngeal mirror with
                                                                 MA) was attached to the telelaryngoscope eyepiece, pro-
a rigid telelaryngoscope connected to a video camera and
                                                                 jecting the telescopic image onto a personal laptop screen
transferring the laryngoscopic image on the TV monitor,
                                                                 (MacBook Pro; Apple Inc., Cupertino, CA). A handheld
and subsequently to a high definition (HD) camera and en-
                                                                 light source with a rechargeable light-emitting diode (LED)
doscopy tower 4,5. Regardless of these improvements, ILS
                                                                 battery was used instead of a conventional cabled white light
has never gained wider acceptance and has been considered
something of a lost art, and recent literature on this tech-     source (Fig. 1B). In all indirect procedures, 10% lidocaine
nique is lacking. Suspension microlaryngoscopy (MLS)             was applied topically by spraying the oropharynx, epiglottis
under general anaesthesia has gradually established itself       with laryngeal inlet, and vocal folds (1 puff equaled 10 mg of
as a standard approach for the removal of VFPs since its         lidocaine, with a maximum safe dose of approximately 300
introduction in the 1960s 6.                                     mg for an average 70 kg adult). After application of the lo-
The recent emergence of wireless endoscopy cameras and           cal anaesthetic, the telelaryngoscope and curved cup forceps
light sources has enabled easy transmission and recording        held in the non-dominant and dominant hand, respectively,
of indirect laryngoscopic findings on computer monitors.         were simultaneously introduced into the patient’s orophar-
Therefore, the aim of this article is to present our modifica-   ynx. The closed tip of the forceps was visually identified
tion of the indirect laryngoscopic technique for the exci-       on the computer screen and advanced over the tongue base,
sion of VFPs that uses wireless components and a personal        epiglottis, and through the laryngeal inlet toward the vo-
computer to monitor the procedure. Although ILS with a           cal fold lesion. The lesion was gently grasped and removed
rigid telelaryngoscope has already been described, to our        in a single anterior-to-posterior motion parallel to the free
knowledge this is the first study to address the outcomes        edge of the vocal fold with respect to its histological struc-
of performing the technique using wireless technology and        ture (Figs. 2, 3). On the other hand, MLS was performed by
to compare the results to those obtained using MLS as a          applying medial traction to the polyp and excising it with
practice standard.                                               microscissors. Dedicated instruments and directoscopes by
                                                                 Kleinsasser (Karl Storz, Tuttlingen, Germany) were used in
                                                                 all microlaryngoscopic procedures.
Materials and methods
All patients who underwent surgery for VFPs using our            Outcome comparison and voice analysis
modified ILS technique at a tertiary referral centre from        To compare the effectiveness of the surgical techniques,
June to October 2020 were included in this prospective           objective acoustic analysis and voice self-assessments
study. To assess the effectiveness of the modified ILS, we       were performed before and four weeks after surgery in both
compared voice outcomes in patients who underwent the            the ILS and MLS groups. Voice samples for the objective
modified ILS with those in patients who underwent suspen-        acoustic analysis were collected using a TASCAM DR 680
sion MLS under general anaesthesia, the standard practice        digital recorder (Teac Corporation, Santa Fe Springs, CA)
at the institution, during the same period. Randomisation        and a Rode NT1-A unidirectional condenser microphone



                                                                                                                                    425
O. Cukic et al.




   A                                                                                B




Figure 1. Principal instrumentation for the indirect laryngoscopic procedure (A) consisting of a pair of Brunnings curved cup forceps and a rigid 70° telelaryn-
goscope. (B) A wireless endoscopy camera and handheld light-emitting diode battery light source attached to the telelaryngoscope.




                                                                                        A                                     B




                                                                                        C                                     D

                                                                                    Figure 3. Polyp of the right vocal fold and the tip of the curved forceps in the
                                                                                    endolarynx (A). Immediate appearance of the vocal folds after polyp removal,
                                                                                    during respiration (B) and phonation (C). Results obtained one month post-
Figure 2. Schematic depiction of the procedure. The vocal fold polyp (*) is         operatively (D).
grasped and avulsed in anterior-to-posterior direction parallel to the free edge
of the vocal fold. This approach is used to create a linear and smallest possible
mucosal defect. Note the spindle-shaped epithelial cells that are also oriented
                                                                                    the sustained vowel /a/ at a comfortable pitch and loud-
parallel to the free edge of the vocal fold (**).                                   ness for at least 3 s in a soundproof room. All recorded
                                                                                    samples were analysed for harmonicity (harmonics-to-
                                                                                    noise ratio [HNR]) and perturbation (jitter and shimmer)
(Rode microphones, Sydney, Australia) placed in front of                            using PRAAT software (ver. 6.1.08; Institute for Phonet-
the patient’s face. The patients were instructed to phonate                         ics, University of Amsterdam, Amsterdam, Netherlands).



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                                                                                      Indirect laryngeal surgery: a dying or evolving art?




The Voice Handicap Index 30 (VHI-30) was used for voice          management of VFPs. This method offers the distinct ad-
self-assessment. The mean treatment cost was calculated          vantage of allowing operations with both hands on a stable
for each surgical group.                                         operative field under microscopic magnification without a
                                                                 specific time limit. However, the surgical field is partially
Statistical analysis                                             obstructed by the endotracheal tube, and occasionally, the
Data normality was tested using the Shapiro–Wilk test.           glottic plane may be difficult to expose, especially in the
Student’s t-test for independent samples was used to ex-         anterior third of the vocal folds. The suboptimal visuali-
plore the differences in the values of the clinical parameters   sation of this particular area, where the majority of VFPs
between the two patient groups. A p value less than ≤ 0.05       occur, can result in misdiagnosis, incomplete excision,
was considered statistically significant. The results in the     abortion of the procedure, and patient dissatisfaction 7. ILS
figures are presented as the mean and standard deviation.        allows the surgeon to observe the awake patient’s larynx
Statistical analysis and figure plotting were performed in       in a physiologic position undistorted by the endotracheal
JupyterLab (v3.2.1, jupyter.org) using Python (v3.8.12, Py-      tube. The rigid 70° telelaryngoscope in our technique pro-
thon) with the SciPy (v1.9.3, scipy.org) and Seaborn pack-       vided an excellent view of the anterior commissure on the
ages (v0.12.1, seaborn.pydata.org).                              computer screen and therefore could be used to treat pa-
                                                                 tients in regions with previously inadequate direct laryn-
                                                                 goscopic exposure. The whole system consisting of the
Results                                                          telelaryngoscope connected to the wireless camera and
A total of 12 patients (nine males and three females) were       LED battery weighs 480 g and can be comfortably held
included in the present study, of whom six underwent the         with a nondominant hand throughout the entire ILS pro-
modified ILS (experimental group) and six underwent              cedure. As a result of miniaturisation and technical revolu-
classical MLS (control group). Both ILS and MLS al-              tion, our system was less than half the size of video camera
lowed successful removal of VFPs without complications           from the videolaryngoscopic setup originally described in
in all patients. The mean age of patients in the ILS group       the late 1980s, which weighed 1.1 kg 10,11. ILS typically
was 54.5 ± 11.8 years, while that in the MLS group was           lasts about 10 minutes, including anaesthesia application
49.8 ± 10.2 years. The size of the lesion removed varied         and control laryngoscopy after removal of the lesion, which
from 2 to 10 mm, but the two groups showed no signifi-           is considerably shorter than other endoscopic procedures,
cant difference in lesion size, although the average size        such as endoscopic sinus surgery. The fully charged wire-
of the lesion was higher in the MLS group (ILS vs MLS:           less camera in our setup can record up to 3.5 hours and is
4.17 ± 2.04 vs 5.83 ± 2.71; t = 1.202, p > 0.05).                therefore sufficient for an average ILS. Moreover, the wire-
Analysis and comparison of different clinical voice pa-          less instruments enabled better ergonomics for the surgeon,
rameters, including the VHI-30 score, jitter, shimmer,           especially easier handling of the endoscope than in wired
and harmonics-to-noise ratio (HNR), before and after sur-        indirect laryngoscopic procedures.
gery showed voice improvement without significant in-            While MLS requires a set of instruments with an operat-
tergroup differences (Fig. 4). The two groups showed no          ing microscope, hospitalisation, and an additional team of
significant differences in the mean values of pre-operative      healthcare professionals (anaesthesiologist, nurse anesthe-
VHI-30 score (t = 0.209, p > 0.05), post-operative VHI-30        tist, and scrub nurse), the ILS technique described above
score (t = 0.728, p > 0.05), pre-operative jitter (t = 1.224,    can be readily performed by a single surgeon with only one
p > 0.05), post-operative jitter (t = 0.34, p > 0.05), pre-op-   surgical instrument in the office and is substantially less ex-
erative shimmer (t = 1.710, p > 0.05), post-operative shim-      pensive. The development of flexible nasopharyngolaryn-
mer (t = 1.248, p > 0.05), pre-operative HNR (t = 0.297,         goscopes with working channels have allowed the treatment
p > 0.05), and post-operative HNR (t = 1.569, p > 0.05).         of various laryngeal conditions in the office, including the
As expected, the average cost of the surgical intervention       removal of selected benign vocal fold lesions 8. Although
was significantly higher in patients who underwent MLS           patients will better tolerate the flexible endoscope passed
(450.44 ± 45.52 EUR) than in those who underwent the             through the nasal cavity than the two instruments in the
modified ILS (44.84 ± 12.69 EUR; t = 21.02, p < 0.001).          oropharynx (as in ILS), this technique ultimately requires
                                                                 two physicians to perform the procedure.
                                                                 More than half of patients undergoing MLS are estimated
Discussion                                                       to experience some minor post-operative complaints, in-
Despite technological advancements, suspension MLS un-           cluding sore throat, tongue numbness, or taste abnormali-
der general anaesthesia remains the standard practice in the     ties 9. These patients also show the potential for iatrogenic



                                                                                                                                    427
O. Cukic et al.




Figure 4. Comparison of different pre-operative and post-operative clinical parameters between the two patients groups. Pre-operative and post-operative val-
ues for the VHI-30 score, HNR, jitter, and shimmer were compared between groups of patients who underwent ILS and MLS interventions. The two groups showed
no significant differences for any of the parameters assessed between the groups. Results are presented as mean ± standard deviation. VHI-30, voice handicap
index 30; HNR, harmonics-to-noise ratio; ILS, indirect laryngoscopic surgery; MLS, microlaryngoscopy.


trauma of the adjacent anatomic structures during laryn-                         swallowing or discrete movements of the vocal folds dur-
goscope placement, specifically to the teeth, lips, or phar-                     ing respiration in an awake patient. Another factor is the
yngeal mucosa. Although mucosal injury may occur with                            20-min time limit for lidocaine anesthetisation, which
opened laryngeal forceps, this form of inadvertent trauma                        represents the time for which the patient can tolerate the
in ILS is avoided by introducing the tip of the forceps                          procedure before experiencing discomfort and gagging.
tightly closed and opening it just in the immediate proxim-                      Therefore, the surgeon should perform the procedure in a
ity of the lesion to be removed. This procedure also elimi-                      rapid and decisive manner, preferably on the first attempt.
nates possible adverse cardiorespiratory events related to                       Submucosal or large lesions that cannot be grasped with
general anaesthesia and is therefore convenient for high-                        Brunnings forceps are better dissected bimanually in MLS
risk patients with significant comorbidities.                                    under general anesthesia.
The ILS procedure described above has several limita-                            The camera delivers a 720 x 480 video resolution, which
tions. This technique requires a cooperative patient to re-                      provides adequate detail for observing the ILS on a 13-inch
main still during the procedure. Therefore, children or pa-                      computer display placed 70 cm from the surgeon’s face. The
tients suffering from dyskinesia or severe tremor and those                      image quality is similar to that of the standard definition ana-
with intractable gagging despite local anaesthesia are not                       logue video camera and television monitor well described in
suitable candidates for ILS. The operative field for ILS                         ILS, but unfortunately not on par with more expensive HD
can be less stable than that for MLS owing to occasional                         wired setups 4,12. Although the wireless HD camera would



428
                                                                                           Indirect laryngeal surgery: a dying or evolving art?




be preferable for ILS, these new systems have so far been        The research was conducted ethically, with all study pro-
used only in small patient series in laparoscopic surgery and    cedures being performed in accordance with the require-
require larger scale clinical validation 13.                     ments of the World Medical Association’s Declaration of
Finally, the number of cases in this study was small, and        Helsinki.
all indirect operations were performed by the first author       Written informed consent was obtained from each patient
at a single centre.                                              for study participation and data publication.

Conclusions                                                      References
Despite the modest number of patients, our data showed
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