Selective laryngeal reinnervation: can rerouting of the thyrohyoid nerve simplify the procedure by avoiding the use of a nerve graft?

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.

Functional Outcomes Following Delayed Laryngeal Reinnervation Of Patients with Vagal Paralysis After Paraganglioma and Schwannoma Surgery

PURPOSE

We present a prospective case series that aimed to report the functional (voice and swallowing) outcomes of delayed laryngeal reinnervation following vagal interruption by resection of vagal paraganglioma and schwannoma.

MATERIALS AND METHODS

A dedicated, anonymized database was established in 2012 with a minimum eighteen-month follow up set for this report. Internationally validated self- and observer-reported measures were recorded preoperatively and at six, 12 and, 18 months together with demographics, diagnoses, and operative details.

RESULTS

A total of eight patients with a median age of 46 (37-54) underwent excision of vagal paraganglioma (five) and schwannoma (three) with few mild complications. Three underwent selective and five non selective reinnervation. Seven out of eight patients underwent synchronous injection medialization. The voice handicap index (VHI-30) improved from a baseline median 83 (range 52-102) to 7.5 (5-58) at 18 months; maximum phonation time improved from median 8 (range 5-15) to 10.5 (8.5-11); voice grade ("G" in grade, roughness, breathiness, asthenia, and strain [GRBAS] scoring) improved from median three (severe impairment, range 0-3) to one (mild impairment, 0-2); Eating Assessment Tool (EAT-10) score improved from median 12 (range 3.5-27) preoperatively to one (0-16); and reflux symptom index (RSI) improved from median 25 (range 17-36) to 7 (0-36). One patient exhibited no discernible reinnervation, while the remainder exhibited good cord bulk and tone, though without purposive abduction.

CONCLUSION

Delayed laryngeal reinnervation for high vagal paralysis is a safe technique associated with good voice and swallowing outcomes by 12-18 months. Potential confounders in this small series and the absence of a control arm both limit conclusions, but this study suggests that further prospective, controlled studies, and/or case registration are merited.

Bilateral Selective Laryngeal Reinnervation for Bilateral Vocal Fold Paralysis in Children

Importance

Bilateral vocal fold paralysis (BVFP) in pediatric patients is a challenging entity with multiple causes. Traditional approaches to managing BVFP include tracheostomy, arytenoidectomy, suture lateralization, cordotomy, and posterior cricoid enlargement. These interventions are used to create a stable airway but risk compromising voice quality.

Objectives

To assess the use of bilateral selective laryngeal reinnervation (SLR) surgery to manage BVFP and restore dynamic function to the larynx in pediatric patients.

Design, Setting, and Participants

In this case series performed at 2 tertiary care academic institutions, 8 pediatric patients underwent bilateral SLR to treat BVFP (5 patients with iatrogenic BVFP and 3 with congenital BVFP) from November 2004 to August 2018 with follow-up for at least 1.5 years.

Interventions

Bilateral selective laryngeal reinnervation surgery.

Main Outcomes and Measures

Flexible laryngoscopy findings, subjective and objective measures of voice quality, subjective swallowing function, and decannulation in patients who were previously dependent on a tracheostomy tube.

Results

Participants included 6 boys and 2 girls with a median age of 9.3 (range, 2.2 to 18.0) years at the time of surgery. All 8 patients were decannulated; 6 patients had preoperative tracheostomies and 2 had perioperative tracheostomies. Voice quality, as measured using the GRBAS (grade, roughness, breathiness, asthenia, strain) scale, improved in 6 of 8 patients after reinnervation, and swallowing was not impaired in any patients. In 2 patients, GRBAS scale scores remained the same before and after surgery. Inspiratory vocal fold abduction was observed on both sides in 5 patients and on 1 side in 2 patients, with no active abduction observed in 1 patient. The follow-up period was more than 5 years in 7 of 8 patients and at least 1.5 years in all patients.

Conclusions and Relevance

Bilateral SLR appears to be a promising treatment option for children with BVFP; it is currently the only option, to our knowledge, with the potential to restore abductor and adductor vocal fold movement. In patients with complete paralysis, this procedure may provide a strategy for airway management and restoration of the dynamic function of the larynx. It could be considered as a first-line technique before endolaryngeal or airway framework procedures, which carry a risk of compromising voice quality.

Surgical Options for Pediatric Bilateral Vocal Cord Palsy: State of the Art

Management of pediatric bilateral vocal cord palsy (BVCP) is a controversial and challenging topic. It may represent a severe obstructive condition usually associated with respiratory distress, and, in such condition, tracheostomy has been considered the gold standard for a long time. Many surgical options have been described and used to increase the glottic space in BVCP (1), with ongoing research of less invasive techniques. The challenge and current trend in our department and in many major pediatric centers is to avoid tracheotomy through an early treatment. Many techniques introduced in the last decade reduced the number of tracheotomies and increased the decannulation rate. Furthermore, we observed a recent increase in attention to preserve the quality of the voice with new techniques, such as endoscopic arytenoid abduction lateropexy which is in our opinion an important innovation to improve glottic space with satisfactory voice results. We present a review of the literature about the evolution of the treatment options for pediatric BVCP during the years.

The Nerve to Thyrohyoid Muscle as a Novel Donor Nerve for Laryngeal Reinnervation

Objectives:

Recurrent laryngeal nerve (RLN) injury may be a consequence of surgical procedures of the skull base, neck, and chest, with adverse consequences to function and quality of life. Laryngeal reinnervation offers a potentially stable improvement in vocal fold position and tone. The classic donor nerve is the ansa cervicalis, but is not always available due to damage or sacrifice during previous neck surgeries. Our objective was to introduce the nerve to the thyrohyoid (TH) muscle as an alternate donor nerve for reinnervation, which has not previously been described.

Methods:

Case series of two patients using the TH nerve for laryngeal reinnervation after RLN injury, with description of surgical harvest.

Results:

Follow-up results are available for 10 months (one patient) and 3 years (one patient) demonstrating both subjective and objective improvement in function. GRBAS scores were reduced. Maximal phonation time was improved. Patient rating of voice was stable or improved postoperatively. One patient described significant preoperative dyspnea which was significantly improved postoperatively, from a score of 24 to 10 out of 40 on the dyspnea handicap index. VHI was improved in one patient, but scores elevated in the other, despite a change from “moderately severe impairment” to “normal voice” subjectively. Neither patient experienced significant complications from the procedure.

Conclusion:

Laryngeal reinnervation procedures provide good outcomes in pediatric patients. When ansa cervicalis is not available as a donor nerve, the nerve to TH provides a reasonable alternative.

Magnetic Laryngeal Reanimation as a Novel Treatment of Vocal Fold Immobility

OBJECTIVE

Vocal fold paralysis may result from surgical complications, trauma, tumor, or unknown causes. When both cords are affected, paramedian fixation can lead to life-threatening obstruction. Current treatments, including tracheostomy, cordotomy, and arytenoidectomy, compromise speech and swallow function to maintain a safe airway. To preserve all three critical laryngeal functions, Otolaryngologists need a solution for bilateral vocal fold paralysis that restores motion. This study uses implantable electromagnet technology to create dynamic vocal fold movement in a proof-of-concept, preliminary model.

METHODS

A prototype was constructed from a neodymium disk magnet and cylindrical solenoid electromagnet coupled to a battery and 3-way switch. The disk magnet was implanted in an ex vivo porcine larynx model lateral to the arytenoid, affixed with suture. The electromagnet was seated in a window cut in the thyroid cartilage.

RESULTS

By driving current in two directions through the electromagnet, the vocal fold was successfully moved towards and away from the electromagnet. The neutral vocal fold opening was 5.8 mm, and the maximal opening was 7.7 mm, representing a 31.4% increase in the cross-sectional area of the glottis.

CONCLUSION

This model demonstrated proof of concept of a magnetic laryngeal reanimation device. The full device will include a respiratory effort sensor and implantable processor to time the action of the magnets with respirations. There is currently no effective treatment to re-establish vocal fold motion in patients with vocal fold paralysis. This system has the potential to give patients with bilateral vocal fold paralysis a surgical option to restore vocal fold motion.