Exercise laryngoscopy in athletes and sportsmen: an easy way to assess exercise-induced laryngeal obstruction.

BACKGROUND: Exercise-induced laryngeal obstruction (EILO) is an exercise-dependent dyspnoea, linked to a laryngeal closure during physical effort. It may concern from 5% to 7% of adolescents and young athletic adults. EILO is a quite recently described condition: standardized diagnostic criteria and consensual management are still to come. Formal diagnosis of EILO requires a continuous laryngoscopy during exercise (CLE). This test allows visualization of laryngeal abnormalities during an effort but is only accessible in specialized centres. AIMS: We wanted to assess performance of a simplified CLE (sCLE) procedure for EILO diagnosis in everyday practice. MATERIAL AND METHODS: The procedure consisted in a continuous flexible videolaryngoscopy during a cycloergometre cardio-pulmonary exercise test. Screening questionnaire and visual scoring of laryngeal abnormalities were performed. Patients clinically suspected of EILO were included from 2018 to 2020. RESULTS: Seventeen consecutive subjects had an indication for sCLE. Fifteen patients underwent sCLE, and EILO-linked significative abnormalities were observed in 80% of them, thus confirming the diagnosis. CONCLUSIONS: CLE can be done successfully in a simple way. Due to its simplicity, tolerance and contribution in EILO diagnosis, this simplified version of CLE may promote its widespread use in ENT and pulmonology practices, as an affordable confirmation test.

Dual laryngeal reinnervation in bilateral vocal fold paralysis: anatomical pitfalls.

BACKGROUND: Bilateral laryngeal reinnervation can be a promising procedure for reanimation of laryngeal muscles, but currently not yet standardized. Besides patient conditions some intraoperative anatomical pitfalls need to be solved. METHODS: Twelve human head and neck specimens (24 sides) have been studied using microdissection and histological serial sections of the nerves. The surgical anatomy of the dual reinnervation procedure according to JP Marie was investigated notably the branching pattern of the phrenic nerve (PN), the Ansa cervicalis (AC) and the recurrent laryngeal nerve (RLN). RESULTS: Despite variations of the AC, a prominent inferior common trunk for sterno-hyoid and sterno-thyroid muscles can be used in more than 90% of the specimens. If the AC is missing because of previous surgery, the tiny nerve of the thyro-hyoid muscle can be used preferred. The PN display a double roots pattern from C3 to C4 cervical plexus in 50% of the specimens. A single root pattern can be found and an end-to-lateral neurorraphy can be used. Intra-laryngeal nerves pattern of the RLN display tiny collaterals which cannot be selected for abduction-adduction activity. Direct implantation of the Y-shape great auricular nerve within the posterior crico-arytenoid muscles can be a reliable method leading to challenging mechanical and functional conditions. CONCLUSION: Several anatomical pitfalls, including intra-operative choices and variants of the donor nerves, but also the challenging intra-laryngeal dissection of the inferior laryngeal nerve need to be solved. A successful laryngeal reinnervation still needs further studies for a simplified procedure.

Vibrotactile guidance for trajectory following in computer aided surgery.

Most conventional computer-aided navigation systems assist the surgeon visually by tracking the position of an ancillary and by superposing this position into the 3D preoperative imaging exam. This paper aims at adding to such navigation systems a device that will guide the surgeon towards the target, following a complex preplanned ancillary trajectory. We propose to use tactile stimuli for such guidance, with the design of a vibrating belt. An experiment using a virtual surgery simulator in the case of skull base surgery is conducted with 9 naïve subjects, assessing the vibrotactile guidance effectiveness for complex trajectories. Comparisons between a visual guidance and a visual+tactile guidance are encouraging, supporting the relevance of such tactile guidance paradigm.

Lamina propria of the human vocal fold: histomorphometric study of collagen fibers.

BACKGROUND: Since the seminal work of M. Hirano, which defined the three-layered lamina propria of the human vocal fold, there has been confusion in the labeling of each layer. Recent studies described the composition of fibers and interstitial molecules within the lamina propria leading to various biomechanical properties. However, collagen fibers appear as the most important structure component. METHODS: We used an optical analysis and the picrosirius-polarization method to describe collagen fibers from six adult and two fetal human larynges fixed in formalin and frontally sectioned in the middle part of the vocal fold. RESULTS: The deep layer of the lamina propria is the most densely organized band of collagen fibers penetrating the superficial muscle bundles of the vocal muscle. The mean thickness of this layer is about 36% of the lamina propria and shows a network of strongly birefringent fibers (collagen type I and III). The superficial layer of the lamina propria is a narrow band of collagen fibers immediately below the basement membrane of the epithelium. The mean thickness of this layer is about 13% of the lamina propria and shows strong birefringent fibers. The intermediate layer is the less densely organized band between the deep and superficial layers. The mean thickness of this layer is about 51% of the lamina propria and shows clear, green weakly birefringent fibers characterized as collagen type III. The fetal lamina propria contains only a monolayer distribution of loose collagen fibers between the epithelium and the vocal muscle. CONCLUSION: These results help describe the distribution of collagen fibers within the lamina propria of the human vocal fold and have implications to understand the cover-body theory of voice production both in the adult and newborn.

Microsurgical anatomy of intralaryngeal distribution of the inferior laryngeal nerve.

The functional results of a partial laryngeal surgery or a laryngeal reinnervation depend on the precise knowledge of the intra laryngeal anatomy of the inferior laryngeal nerve (ILN). Ten human larynges without known laryngeal disorders were obtained from human cadavers for ILN microdissection. Intra laryngeal ILN branching patterns were determined bilaterally. The lengths of the vertical, genu and oblique segments of the anterior division of ILN and the distance between the nerve within the paraglottic space and the cricothyroid articulation (CTA) were measured with a digital microcaliper. The mean lengths of the vertical, genu and oblique segments were 10.82, 5.89 and 9.29 mm, respectively. The mean distance between the nerve in the paraglottic space and the CTA was 11.20 mm. Key anatomical landmarks of the abductor division (vertical and genu segments of ILN) were the lateral border of posterior cricoarytenoid (PCA) muscle and the superior ligament of the CTA. The two-branch pattern for the lateral border of the PCA muscle has been the most frequent (50%). A branch of interarytenoid muscle (IA) originated from the genu segment. One or two branches for the PCA muscle has been identified in 75% of cases from the IA neural plexus on the front side of PCA muscle. The adductor division for the thyroarytenoid muscle and the lateral cricoarytenoid muscle was the oblique segment of the nerve. We conclude that abductor and adductor divisions of intra laryngeal ILN can be readily identified and the knowledge of key landmarks allows preservation of the ILN during partial surgery of the larynx and possibly selective muscle reinnervation.