Craig Berzofsky

Evaluation of Functional Recovery of Recurrent Laryngeal Nerve Using Transoral Laryngeal Bipolar Electromyography : A Rat Model

Objectives: We developed a standardized method of minimally invasive transoral laryngeal (ToL) bipolar electromyography (EMG) for evaluation of recurrent laryngeal nerve (RLN) recovery after a controlled crush injury in a rat model. Methods: Ten 200- to 250-g Sprague-Dawley rats underwent a controlled crush injury to the left RLN performed with 60 seconds of use of a calibrated aneurysm clamp with a closing force of 0.61 N. Serial ToL bipolar EMG was performed on adductor muscles and the posterior criocoarytenoid muscle during spontaneous vocal fold motion under anesthesia. Each animal underwent ToL EMG immediately after surgery and 1, 3, and 6 weeks after surgery. Results: The EMG signals showed normal motor unit potentials and recruitment patterns 3 weeks after crush injury. Endoscopic evaluation of vocal fold mobility yielded consistently normal findings 6 weeks after crush injury. Conclusions: We have developed a standardized method of crush injury to the rat RLN model and a minimally invasive transoral bipolar spontaneous EMG technique to serially evaluate and follow nerve injury and recovery in rats. This model is intended to simulate intraoperative RLN injury, to elucidate the electrophysiological events that occur during nerve recovery, and to form the basis for studying agents to enhance such recovery.

Recurrent laryngeal nerve transection and anastomosis: rat laryngeal motoneuron survival and effect of the anastomosis site.

Objectives: We investigated the quantity of recurrent laryngeal nerve motoneurons (RLNMs) that survive after transection and anastomosis of the rat recurrent laryngeal nerve (RLN), as well as the impact of the anastomosis site on RLN regeneration. Methods: Ten rats underwent right RLN transection and anastomosis. After 16 weeks, Fluoro-Ruby (FR) was applied to the RLN that was transected proximal or distal to the anastomosis site. The brain stems were harvested, and the nucleus ambiguus was evaluated for labeled RLNMs. The RLNM counts were compared to each other and to those from 3 control rats in which FR was applied to an acutely transected RLN. Results: The number of RLNMs that were stained after RLN transection, anastomosis, and regeneration was consistent with the total number of RLNMs in the nucleus ambiguus of control rats. This finding confirms that most RLNMs survived after RLN transection and anastomosis. The quantity of labeled RLNMs was statistically similar whether the FR was applied proximal or distal to the anastomosis, implying that most of the viable axons that were present proximal to the anastomosis crossed into the distal nerve. Conclusions: Rat RLNMs survive nerve transection, anastomosis, and regeneration. The anastomosis site does not significantly impede axonal regeneration, and most of the axons traverse the anastomosis into the distal nerve.

Variability of postoperative esophagrams after endoscopic cricopharyngeal myotomy: technique dependence.

Objectives: We illustrate the dependence of postoperative day (POD) 1 esophagram findings on the closure technique used after endoscopic cricopharyngeal myotomy (ECPM). Methods: We performed a retrospective chart review of POD 1 fluoroscopic examinations of the cervical esophagus utilizing contrast dye after ECPM to assess radiologic findings associated with three different techniques of addressing the exposed buccopharyngeal fascia (BPF). Results: Each technique resulted in specific and different findings on the POD 1 esophagram. When the BPF was untreated, the esophagram demonstrated a pseudodiverticulum with free flow of contrast dye. When a fibrin glue seal was used, the esophagram demonstrated a curvilinear focus of contrast dye projected over the retropharyngeal soft tissue persisting after the swallow, similar to a leak. When fibrin glue application was combined with single-suture reapproximation of the mucosal incision, the pattern was similar to esophagrams performed 6 weeks after myotomy. Conclusions: Different techniques used to address the exposed BPF following ECPM result in specific findings on the POD 1 esophagram. Recognition of these imaging differences and open communication with the fluoroscopist will avoid a misdiagnosis of a pharyngeal leak, which might cause an unnecessary delay of oral feeding and hospital discharge.

Trigger Reduction Prior to Systemic Drugs for Neurogenic Chronic Cough: Nonsystemic Treatment of Neurogenic Cough

Neurogenic chronic cough typically presents as a postviral chronic cough, often with paroxysms of coughing preceded by a tickle sensation with multiple triggers and often recalcitrant to multiple treatments for reflux disease, sinus disease, and asthma. Current treatment uses neuromodulating agents with moderate success. Post nasal drainage and laryngopharyngeal reflux can be triggers in the setting of laryngopharyngeal hypersensitivity. Treatment will focus on trigger reduction using nasal toilet and a dietary regimen for laryngopharyngeal reflux.

Indications for Surgical Repair of Type 1 Laryngeal Cleft

Objectives: Type 1 laryngeal cleft (T1LC) is a congenital deficiency in the posterior glottis, resulting in a communication between the hypopharynx and glottis. No consensus treatment paradigm exists for timing and criteria for patient selection for surgical repair. Our goal is to assess whether patient characteristics can help predict improvement after surgery. Methods: After Institutional Review Board exemption, a retrospective chart review was performed for patients undergoing surgery to diagnose a T1LC. Charts were examined for age, presenting symptoms, comorbidities, pre/postoperative videoflouroscopic swallow study reports, and outcomes. Results: Ninety-seven patients with clinical suspicion for T1LC underwent direct laryngoscopy and bronchoscopy, and 63 (64%) were diagnosed with a T1LC. Twenty-two patients (63%) undergoing surgery achieved clinical or radiographic improvement. There was no difference in average age, aspiration, or penetration between clinical improvement and no improvement groups. Of 13 patients with comorbidities that increase their risk of aspiration, 12 were significantly improved. There were 5 complications, which were managed conservatively. Conclusions: Our experience supports the repair of T1LC repair at time of diagnostic laryngoscopy if satisfactory improvement is not noted with conservative treatment. This should be performed without segregation for age, comorbidities, or degree of dysphagia. Our technique is performed with minimal complications and achieves satisfactory results.

Postoperative Management of Superior Laryngeal Nerve Paralysis

Superior laryngeal nerve (SLN) injury can cause many symptoms, the most common complaints being the inability to access the upper vocal range, difficulty projecting the voice, and vocal fatigue. Treatment with voice therapy has some limited utility in these patients. Its greatest benefit may be in preventing or treating muscle tension dysphonia, developed in compensation of the SLN injury. Numerous static and one theoretical dynamic procedure have been proposed. These procedures can help augment the cricothyroid distance. These procedures may elevate the modal pitch of the voice with varying success, with only a few patients appreciating improvement in their pitch modulation. The most promising technique described is a muscle-nerve-muscle anastomosis with a neural conduit. This allows the nerve of the healthy cricothyroid muscle to innervate the paralyzed cricothyroid and ultimately leads to simultaneous bilateral muscle contraction. Although patients undergoing this procedure have shown some benefit, it has been reported only in patients who had additional procedures for voice restoration. This results in multiple confounding variables and the true utility of the procedure is unknown. Further research is needed to help identify an optimal treatment for SLN paralysis. Due to the dearth of successful treatment options, prevention of SLN injury should be emphasized.

Variable Esophagram Post-Endoscopic Cricopharyngeal Myotomy

OBJECTIVE: 1) To validate the Spanish translation of the disorder-specific health status instrument (Singing Voice Handicap Index, SVHI) for use in patients with singing problems. 2) To determine the SVHI threshold of a healthy population of professional classical singers. METHOD: S-VHI was translated into Spanish from validated version in English. The questionnaire was completed by 29 dysphonic singers and 81 healthy singers between January and December 2009. Test-retest reliability, internal consistency, and construct validity were assessed. RESULTS: Results showed high test-retest reliability (r 0.63, P .000), and high item-total correlation for the Spanish version of the SVHI. Internal consistency demonstrated a Cronbach’s alpha of 0.96, and the correlation between the SVHI and self-rated singing voice impairment was 0.52 (p .000). Dysphonic singers had worse SVHI scores than normal singers (ANOVA, F 10.9, P 002). CONCLUSION: The Spanish version of the questionnaire translated into S-VHI is a validated tool with proper internal consistency and reliability. The average score of the S-VHI singers in healthy singers is 20% of the maximum possible score of the questionnaire, well above the average score in a healthy population for the spoken voice with HIV-specific-30 (6.7%).