Dysphagia Outcomes Following Surgical Management of Unilateral Vocal Fold Immobility: A Systematic Review and Meta-analysis

Objective To assess dysphagia outcomes following surgical management of unilateral vocal fold immobility (UVFI) in adults. Data Sources Ovid MEDLINE, Embase, Web of Science, and Cochrane Central. Review Methods A structured literature search was utilized, and a 2-researcher systematic review was performed following PRISMA guidelines. Extractable data were pooled, and a quantitative analysis was performed with a random effects model to analyze treatment outcome and complications by procedure. Results A total of 416 publications were screened and 26 met inclusion criteria. Subjects encompassed 959 patients with UVFI who underwent 916 procedures (n = 547, injection laryngoplasty; n = 357, laryngeal framework surgery; n = 12, laryngeal reinnervation). An overall 615 were identified as having dysphagia as a result of UVFI and had individually extractable outcome data, which served as the basis for a quantitative meta-analysis. In general, dysphagia outcomes after all medialization procedures were strongly positive. Quantitative analysis demonstrated a success rate estimate of 90% (95% CI, 75%-100%) for injection laryngoplasty and 92% (95% CI, 87%-97%) for laryngeal framework surgery. The estimated complication rate was 7% (95% CI, 2%-13%) for injection laryngoplasty and 15% (95% CI, 10%-20%) for laryngeal framework surgery, with minor complications predominating. Although laryngeal reinnervation could not be assessed quantitatively due to low numbers, qualitative analysis demonstrated consistent benefit for a majority of patients for each procedure. Conclusion Dysphagia due to UVFI can be improved in a majority of patients with surgical procedures intended to improve glottal competence, with a low risk of complications. Injection laryngoplasty and laryngeal framework surgery appear to be efficacious and safe, and laryngeal reinnervation may be a promising new option for select patients.

Primary Nonselective Laryngeal Reinnervation in Iatrogenic Acute Recurrent Laryngeal Nerve Injury: Case Series and Literature Review

Treating an acutely injured recurrent laryngeal nerve by primary nonselective laryngeal reinnervation (LR) during thyroidectomy is encouraged to minimize postoperative morbidity. Performing a concurrent transoral temporary injection laryngoplasty (IL) may improve the patient’s voice while waiting for the effect of successful reinnervation. Chronological multidimensional voice outcomes (qualitative and quantitative) and combination of the primary nonselective LR with concurrent transoral IL were not explicitly demonstrated in previous cases that published the literature. In this study, the authors presented the multidimensional voice parameters of 3 patients undergoing primary nonselective LR with concurrent IL during thyroidectomy. The parameters were measured at different time points (2 weeks and 1, 3, 6, and 12 months) following the surgery. Laryngeal electromyography was done at 1 to 2 months and 12 months postsurgery. The results showed that the voices, qualitatively and quantitatively, were within normal range at within 3 months postintervention. The parameters were slightly beyond the normal limit at 3 months and returned to normal at 6 months postintervention and beyond. The LEMG depicted evidence of successful reinnervation in which the motor unit was normal comparable to the opposite normal vocal fold.

Subcutaneous Ports for Chronic Nerve Cuff and Intramuscular Electrode Stimulation in Animal Models

Objective Tracking recovery after nerve injury may require many intermittent assessments over long periods, preferably with non- or minimally invasive methods. We developed subcutaneous electrical connection ports (ECPs) for repeated connection to nerve cuff or intramuscular electrodes via transdermal needles and evaluated them during studies of laryngeal reinnervation. Study Design Animal experiment. Setting Laboratory. Methods ECPs were designed and 3-dimensionally printed for connection to bipolar electrodes with biocompatible polymers. Dual compartments filled with conductive silicone capped with nonconductive silicone were used to make the connections between electrode leads and transdermally inserted needles. Ten dogs (19-29 kg) were implanted with 22 ECPs. In 7 dogs, 11 electrodes were placed on recurrent laryngeal nerves proximal to transection and suture repair to track laryngeal reinnervation. In 6 dogs, 8 spinal accessory nerve cuff electrodes were used to stimulate neck muscle contraction. In 2 dogs, 3 electrodes were implanted in the thyroarytenoid muscle. Stimulation thresholds, electromyography, and videolaryngoscopic imaging were obtained in 156 tests over survival periods up to 32 months. Stimulation data provided information about ECP performance. Results ECPs added negligible resistance to electrodes (mean ± SD, 2.14 ± 0.9 Ω). Despite some electrode leads breaking distally, ECPs were reliable and well tolerated at implant sites and enabled periodic assessment of nerve and muscle function over the time course of laryngeal reinnervation. Histology showed ECP encapsulation as thin layers of connective tissue and minimal acute inflammation. Conclusion Custom ECPs are easily fabricated and cause little tissue reaction over months to years of subcutaneous implantation, facilitating long-term physiologic studies.