Nerve-muscle transplantation to the paraglottic space after resection of recurrent laryngeal nerve

Management Options for Bilateral Vocal Fold Impairment: Scoping Review to Assess the Potential of Soft Robotics Solutions

OBJECTIVES

This scoping review aims to comprehensively assess current surgical interventions for bilateral vocal fold paralysis (BVFP), addressing the heterogeneity in treatment outcomes. Additionally, it explores the potential role of soft robotics as an innovative approach to improve outcomes in BVFP management.

METHODS

This scoping review systematically examines literature from MEDLINE, Embase, and Scopus databases. Inclusion criteria encompass studies related to BVFP management with measurable subjective or objective outcomes. Studies with populations solely under the age of 18 were excluded. Four reviewers independently screened 2263 studies, resulting in the selection of 125 papers for data extraction. Information included study characteristics, interventions, and outcomes. Data synthesis involved both quantitative and qualitative analyses.

RESULTS

The review identified 145 surgical interventions grouped into seven types: tracheostomy, cordectomy, arytenoidectomy, lateralization, combined procedures and others. Outcome measures fit into the following categories: "objective voice," "subjective voice," "aerodynamics," "dyspnea," "decannulation," "swallow," and "quality of life." Positive outcomes were predominant across all interventions, with arytenoidectomy and cordectomy showing relatively lower rates of successful objective and subjective voice outcomes. This could be the result of prioritizing improved airway status. Soft robotics is hypothesized as a potential solution to the limitation of current interventions sacrificing voice for breathing.

CONCLUSIONS

The main aim of current surgical interventions for BVFP is expanding glottic aperture. Yet achieving optimal outcomes remains elusive due to complex airflow dynamics and potential impacts on phonatory function and swallowing. The current review underscores the need for a more nuanced, personalized approach, considering individual anatomical and physiological variations. Soft robotics emerges as a promising avenue to address this variability. However, challenges such as implantation procedures, long-term care, and patient education require careful consideration. Collaboration between medical professionals, engineers, and robotics specialists is essential for translating these principles into practical solutions.

Long‐Term Outcomes of End‐Flexible‐Rigidscopic Transoral Surgery for Pharyngolaryngeal Cancer

OBJECTIVE

End-flexible-rigidscopic transoral surgery (E-TOS) is a new and minimally invasive transoral surgery for resection of Tis-selected T3 pharyngolaryngeal cancers. We evaluated long-term oncological outcomes and whether postoperative voice and swallowing function were preserved following E-TOS.

METHODS

In this retrospective single-center study, 154 patients treated with E-TOS using a curved retractor, flexible-tip rigid endoscope, and thin curved instruments were included. Their survival rate, larynx preservation rate, and disease control rate were estimated using the Kaplan-Meier method. Postoperative voice function was evaluated using both objective and subjective tests. Postoperative swallowing function was assessed using the Hyodo score and the functional outcome swallowing scale.

RESULTS

The 3-year and 5-year overall survival, disease-specific survival, disease-free survival, laryngectomy-free survival, local control, and loco-regional control rates post E-TOS were 89.8% and 82.2%, 95.6% and 92.3%, 78.5% and 70.3%, 87.2% and 80.9%, 93.9% and 92.5%, and 87.2% and 85.7%, respectively. Both objective and subjective postoperative voice and swallowing function tests were within normal limits in more than 90% of the patients.

CONCLUSION

E-TOS is an effective, safe, low-cost, and minimally invasive transoral surgery for Tis-selected T3 pharyngolaryngeal cancer; it also preserves postoperative voice, larynx, and swallowing function.

LEVEL OF EVIDENCE

4 Laryngoscope, 133:1415-1424, 2023.

Management of bilateral recurrent laryngeal nerve paresis after thyroidectomy

Bilateral recurrent laryngeal nerve (RLN) injury is rare for benign thyroid lesions (0.2%). After extubation-stridor, respiratory distress, aphonia occurs due to the closure of the glottic aperture necessitating immediate intervention and emergency intubation or tracheostomy. Intra-operative identification and preservation of the RLN minimizes the risk of injury. It is customary to expect RLN problems after thyroid surgery especially if malignancy, big thyroid, distorted anatomical problems and difficult airway that can lead to intubation trauma. Soon after extubating, it is essential to the anesthetist to check the vocal cord movements on phonation and oropharyngeal reflexes competency. But this case is specially mentioned to convey the message that in spite of absence of above mentioned predisposing factors for complications and good recovery profile specific to thyroid, there can be unanticipated airway compromise that if not attended to immediately may cost patient's life. This is a case of postextubation stridor following subtotal thyroidectomy due to bilateral RLN damage and its management.

Immediate Recurrent Laryngeal Nerve Reconstruction and Vocal Outcome

OBJECTIVE

The objective of this prospective study was to assess the long-term effects of immediate reconstruction of the recurrent laryngeal nerve (RLN) during thyroid cancer extirpation on postoperative phonatory function.

SUBJECTS AND METHODS

The subjects were 22 patients with advanced thyroid cancer who underwent resection of the primary lesion and involved RLN. RLN paralysis was seen in 12 patients preoperatively and involvement of the RLN was noted intraoperatively in 10. Immediate reconstruction of the RLN was performed on eight patients using the great auricular nerve and one underwent direct anastomosis of the RLN stumps (group I). Nine patients opted not to have phonosurgical procedures (group II). The remaining four had arytenoid adduction immediately after cancer extirpation (group III). Phonatory function (stroboscopy, maximum phonation time [MPT], mean airflow rate [MFR], harmonics-to-noise ratio [HNR], jitter, and shimmer) was followed for at least 9 months.

RESULTS

Minimal or no glottal gap during phonation was observed in six patients in group I, whereas the patients in group II had a large gap along the entire fold. HNR, MPT, and MFR were significantly better in group I (17.7 +/- 3.6 dB, 15.1 +/- 6.3 s, and 100 +/- 32 mL/s, respectively) than in group II (12.1 +/- 2.9 dB, 5.4 +/- 3.1 s, and 430 +/- 207 mL/s, respectively). Patients in group III had a gap of varying degrees along the membranous fold. Although HNR, shimmer, and MPT in group III were comparable to group I, the other parameters were less favorable than in group I.

CONCLUSION

Immediate RLN reconstruction at the time of thyroid cancer extirpation can provide excellent postoperative phonatory function.

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.

[Therapy for unilateral vocal fold palsy]

The main symptom of unilateral vocal fold palsy is hoarseness, which can cause considerable disturbance to the patient depending on its extent and the patient's individual situation. Therapy aims at the restitution of a tuneful and resilient voice, which can be achieved by surgical or conservative means, improving the glottal closure and synchronizing the vocal fold vibrations during phonation. Vocal therapy is a common conservative method that may be supported by psychotherapeutic or physical procedures. In surgical therapy, there is a distinction between techniques of endoscopic augmentation by injecting different materials into the vocal folds and transcutaneous laryngeal framework surgery, i.e., transferring the paralyzed vocal fold to the glottal midline. Particularly apt for injection are biocompatible materials amount and position whose can easily be controlled. However, the inevitable resorption of many materials causes deterioration in voice quality. Furthermore, the change of vocal fold morphology obstructs regular phonatory vibration. On the other hand, medialization thyroplasty leads to permanent voice amelioration without a substantial complication rate when performed by experienced surgeons.