Occurrence and recovery of vocal cord paralysis after minimally invasive McKeown esophagectomy, risk factors, and clinical outcome

BACKGROUND

This study aimed to observe the occurrence of recurrent laryngeal nerve injury after McKeown esophagectomy for esophageal squamous cell carcinoma, as well as its recovery and influencing factors within 7 months after surgery.

METHODS

From July 2020 to July 2021, among all patients who underwent minimally invasive McKeown esophagectomy, 90 patients who developed vocal cord paralysis after surgery were included in the study. These patients underwent endoscopic vocal cord function assessment every 1 to 2 months and continued until 7 months postoperatively.

RESULTS

Among all 388 patients undergoing esophagectomy, 23.2% (90/388) of patients suffered postoperative vocal cord paralysis. Left, right, and bilateral injuries were confirmed in 73 (81.1%), 12 (13.3%), and 5 patients (5.6%), respectively. With a median recovery time being 183 days, the cumulative overall recovery rate was 65.4% at 7 months, 68.6% for the left side, 55.6% for the right, and 20.0% for bilateral injuries. In multivariable analysis, cervical paraoesophageal lymph node dissection and conventional thoracoscopic-assisted esophagectomy were demonstrated to be independent risk factors associated with non-recovery of vocal cord paralysis.

CONCLUSIONS

After intensive endoscopic follow-up, a cumulative vocal cord paralysis recovery rate of 65.4% within 7 months was observed in patients after minimally invasive McKeown esophagectomy. Cervical paraoesophageal lymph node dissection and conventional thoracoscopic-assisted esophagectomy were demonstrated to be risk factors hindering vocal cord paralysis recovery.

A comparative analysis of laryngeal nerve damage in patients with idiopathic vocal cord paralysis exhibiting different paralytic sides

Objective

To assess the extent of recurrent laryngeal nerve (RLN) and superior laryngeal nerve (SLN) damage in patients with idiopathic vocal cord paralysis (IVCP) exhibiting different paralytic sides.

Methods

A total of 84 IVCP cases were evaluated using stroboscopic laryngoscopy, voice analysis, and laryngeal electromyography (LEMG). The results were compared between patients with left-sided paralysis and right-sided paralysis based on different disease courses (less than or more than 3 months).

Results

Initially, the average age and disease progression of IVCP patients were found to be similar regardless of the side of paralysis (p > .05). Additionally, there were no significant variations in voice indicators, such as MPT, DSI, and VHI, between IVCP patients with left and right vocal cord paralysis (p > .05). Furthermore, no disparities were detected in the latencies and amplitudes of the paralyzed RLN and SLN, as well as the durations and amplitudes of the action potentials in the paralyzed TM and PCM, among IVCP patients with left and right vocal cord paralysis (p > .05). Notably, the amplitudes of the left paralytic CM were significantly lower than those of the right paralytic CM (0.45 vs. 0.53, Z = -2.013, p = .044). In addition, no disparities were observed in APDs and amplitudes between the ipsilateral PCM and TM, either for patients with left or right vocal fold paralysis (p > .05). Finally, all the IVCP patients were subdivided into two subgroups according to different disease course (less than or more than 3 months), and in each subgroup, the comparison of voice indicators and LEMG results in IVCP patients with left or right vocal fold paralysis were similar with the above findings (p > .05).

Conclusion

Overall, the degree of RLN and SLN damage appeared to be similar in IVCP patients with left and right vocal cord paralysis, provided that the disease course was comparable.

Level of Evidence

4.

Changes in vocal fold gene expression and histology after injection augmentation in a recurrent laryngeal nerve injury model

OBJECTIVE

To investigate changes in neuroregenerative pathways with vocal fold denervation in response to vocal fold augmentation.

METHODS

Eighteen Yorkshire crossbreed swine underwent left recurrent laryngeal nerve transection, followed by observation or augmentation with carboxymethylcellulose or calcium hydroxyapatite at two weeks. Polymerase chain reaction expression of genes regulating muscle growth (MyoD1, MyoG and FoxO1) and atrophy (FBXO32) were analysed at 4 and 12 weeks post-injection. Thyroarytenoid neuromuscular junction density was quantified using immunohistochemistry.

RESULTS

Denervated vocal folds demonstrated reduced expression of MyoD1, MyoG, FoxO1 and FBXO32, but overexpression after augmentation. Healthy vocal folds showed increased early and late MyoD1, MyoG, FoxO1 and FBXO32 expression in all animals. Neuromuscular junction density had a slower decline in augmented compared to untreated denervated vocal folds, and was significantly reduced in healthy vocal folds contralateral to augmentation.

CONCLUSION

Injection augmentation may slow neuromuscular degeneration pathways in denervated vocal folds and reduce compensatory remodelling in contralateral healthy vocal folds.

Unilateral vocal fold paralysis as a port complication

Unilateral vocal fold paralysis (UVFP) is a frequent finding in otorhinolaryngology practice, but its occurrence as a port complication was very rarely described in English Literature. The authors report a 55-year-old woman with a pancreatic adenocarcinoma who presented a left vocal fold paralysis that occurred concurrently with a venous thrombosis of the left subclavian vein, where a totally implantable venous-access had been previously placed. Although the patient's oncologic disease, that could mislead to a neoplastic cause of the UVFP, the authors came across with an unusual etiology and to their best knowledge, it is the first case of irreversible UVFP associated with onsite thrombosis of the vessel where a port was implanted. The objective of this article is to present and discuss this rare case of UVFP secondary to a port complication and to review the main mechanisms of iatrogenic vocal fold paralysis related to these devices.

The Causes and Laryngeal Electromyography Characteristics of Unilateral Vocal Fold Paralysis

OBJECTIVE

To investigate the causes and laryngeal electromyography (LEMG) characteristics of unilateral vocal fold paralysis (UVFP).

METHODS

We retrospectively analyzed the history and LEMG of 337 patients with unilateral vocal fold immobility. The etiology was reviewed and the characteristics of LEMG (including spontaneous potential, recruitment potential, evoked potential, synkinesia, and et al.) were analyzed.

RESULTS

The causes included injury (177 cases, 52.5%), idiopathic causes (72 cases, 21.4%), infection (61 cases, 18.1%), tumor and compressive factors (27 cases, 8.0%). Among the injury group, 161 cases were caused by surgery (111 cases of thyroid surgery), and 16 cases were caused by trauma. LEMG showed that complete nerve injury was present in 72.9% of the injury group, 66.7% of the tumors or compressive factors group, 49.2% of the infection group, and 44.4% of the idiopathic group. Of the 337 patients, 136 patients (40.4%) had synkinesia in the posterior cricoarytenoid muscles, and only two of these patients also had synkinesia in the thyroarytenoid muscles. The proportion of complete recurrent laryngeal nerve (RLN) injury in patients with synkinesia was higher than that of patients without synkinesia.

CONCLUSION

The main cause of vocal fold paralysis is neck surgery, most commonly thyroid surgery. Patients with different causes of paralysis had different severities of RLN injury. LEMG showed that surgery or trauma accounted for the highest proportion of complete nerve injury. Patients with severe RLN injury were more prone to synkinesia, and the posterior cricoarytenoid muscles were more likely to have synkinesia than the thyroarytenoid muscles.

Does Medialization Improve Swallowing Function in Patients with Unilateral Vocal Fold Paralysis? A Systematic Review

Glottal incompetence caused by unilateral vocal fold paralysis (UVFP) is a common cause of dysphagia and aspiration. Treatments targeted at reducing glottal incompetence by injection augmentation or medialization thyroplasty are well established at improving voice outcomes, but improvements in swallowing function are less clear. The objective of this systematic review was to determine the impact of vocal fold medialization on dysphagia outcomes. Six electronic bibliographic databases and one clinical trial registry were searched on 3/13/2020. Our patient population were adult patients with verified UVFP that underwent vocal fold medialization. We limited review to prospective studies that had formal dysphagia assessment both before and after medialization. Nine studies met selection criteria (7 prospective case series and 2 prospective cohort studies) totaling 157 patients. The most common etiology of UVFP was iatrogenic (74/157; 47%). The majority of patients underwent injection augmentation (92/157; 59%), and the remaining underwent medialization thyroplasty. A variety of methods were used to assess changes in dysphagia including patient-reported outcome measures, flexible endoscopic evaluation of swallowing, videofluoroscopic swallow study, and high-resolution manometry. 7/9 studies demonstrated clinically significant improvement in swallowing function following medialization; 4/9 studies demonstrated statistically significant improvement, and three studies did not show statistically significant improvement after intervention. Study participants and outcome measures evaluating swallowing function in this review were heterogeneous. Moreover, the reviewed studies are concerning for multiple risks of bias impacting their conclusions. Taken together, this systematic review demonstrates limited evidence that injection augmentation and medialization thyroplasty improve swallowing function and/or safety.

Surgery for bilateral vocal fold paralysis: Systematic review and meta-analysis

Objectives

To determine the decannulation rate (DR) and revision surgery rate after surgery for bilateral vocal fold paralysis (BVFP).

Data Sources

Five databases (MEDLINE, PubMed, Embase, Web of Science, Scopus) were searched for the period 1908-2020.

Methods

The systematic literature review followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Data were pooled using a random-mixed-effects model. Randomized controlled trials and non-randomized studies (case-control, cohort, and case series) were included to assess DR and revision surgery rate after different surgical techniques for treatment of BVFP.

Results

The search yielded 857 publications, of which 102 with 2802 patients were included. DR after different types of surgery was: arytenoid abduction (DR 0.93, 95%-confidence interval [CI], 0.86-0.97), endolaryngeal arytenoidectomy (DR 0.92, 95%-CI, 0.86-0.96), external arytenoidectomy (DR 0.94; 95%-CI, 0.71-0.99), external arytenoidectomy and lateralisation (DR 0.87; 95%-CI, 0.73-0.94), laterofixation (DR 0.95; 95%-CI, 0.91-0.97), posterior cordectomy (DR 0.97, 95%-CI, 0.94-0.99), posterior cordectomy and arytenoidectomy (DR 0.98, 95%-CI, 0.93-0.99), posterior cordectomy and subtotal arytenoidectomy (DR 0.98, 95%-CI, 0.88-1.00), posterior cordotomy (DR 0.96, 95%-CI, 0.84-0.99), reinnervation (0.69, 95%-CI, 0.12-0.97), subtotal arytenoidectomy (DR 1.00, 95%-CI, 0.00-1.00) and transverse cordotomy (DR 1.0, 95%-CI, 0.00-1.00). No significant difference between subgroups for DR could be found (Q = 15.67, df = 11, p = 0.1540). The between-study heterogeneity was low (τ2 = 2.2627; τ = 1.5042; I2 = 0.0%). Studies were at high risk of bias.

Conclusion

BLVP is a rare disease and the study quality is insufficient. The existing studies suggest a publication bias and the literature review revealed that there is a lack of prospective controlled studies. There is a lack of standardized measures that takes into account both speech quality and respiratory function and allows adequate comparison of surgical methods.

Selective Electrical Surface Stimulation to Support Functional Recovery in the Early Phase After Unilateral Acute Facial Nerve or Vocal Fold Paralysis

This article addresses the potential clinical value of surface electrical stimulation in the acute phase of denervation after the onset of facial nerve or recurrent laryngeal nerve paralysis. These two nerve lesions are the most frequent head and neck nerve lesions. In this review, we will work out several similarities concerning the pathophysiology features and the clinical scenario between both nerve lesions, which allow to develop some general rules for surface electrical stimulation applicable for both nerve lesions. The focus is on electrical stimulation in the phase between denervation and reinnervation of the target muscles. The aim of electrostimulation in this phase of denervation is to bridge the time until reinnervation is complete and to maintain facial or laryngeal function. In this phase, electrostimulation has to stimulate directly the denervated muscles, i.e. muscle stimulation and not nerve stimulation. There is preliminary data that early electrostimulation might also improve the functional outcome. Because there are still caveats against the use of electrostimulation, the neurophysiology of denervated facial and laryngeal muscles in comparison to innervated muscles is explained in detail. This is necessary to understand why the negative results published in several studies that used stimulation parameters are not suitable for denervated muscle fibers. Juxtaposed are studies using parameters adapted for the stimulation of denervated facial or laryngeal muscles. These studies used standardized outcome measure and show that an effective and tolerable electrostimulation of facial and laryngeal muscles without side effects in the early phase after onset of the lesions is feasible, does not hinder nerve regeneration and might even be able to improve the functional outcome. This has now to be proven in larger controlled trials. In our view, surface electrical stimulation has an unexploited potential to enrich the early therapy concepts for patients with unilateral facial or vocal fold paralysis.

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.

Intraoperative trans-laryngeal ultrasound (LUSG) of the vocal cord is a novel method of confirming the recurrent laryngeal nerve (RLN) integrity during thyroid and neck surgery

BACKGROUND

Eliciting a normal electromyography signal has been the usual method to confirm the functional integrity of the recurrent laryngeal nerve during intraoperative nerve monitoring. Given that oscillations of the vocal cord can be detected with trans-laryngeal ultrasound when the ipsilateral recurrent laryngeal nerve is stimulated with the endotracheal tube in situ, we aimed to compare the accuracy and cost of this novel method with the conventional electromyography method.

METHODS

Consecutive patients who underwent elective thyroid, parathyroid or neck dissection procedures were included. The NIM-Neuro 3.0 system was used. Endotracheal tube-based surface electrodes were utilized for electromyography signal recording. Standard anesthetic technique was adopted. Recurrent laryngeal nerve integrity was verified by both detection methods (laryngeal ultrasound and electromyography) independently. Vocal cord function was validated by flexible direct laryngoscopy postoperatively. For each method, concurrence with flexible direct laryngoscopy was defined as "true-positive" or "true-negative," based on the presence or absence of vocal cord paresis. Accuracy was calculated as the sum of all true positives and negatives divided by the total of nerves-at-risk. The cost of each method was calculated.

RESULTS

One hundred and four patients were eligible. Total number of nerves-at-risk was 155. Based on flexible direct laryngoscopy findings, the test sensitivity, specificity, positive predictive value, and negative predictive value of intraoperative laryngeal ultrasound were 75.0%, 99.3%, 85.7%, and 98.6%, respectively, while those of electromyography were 87.5%, 98.0%, 70.0%, and 99.3%, respectively. The prognostic accuracy in laryngeal ultrasound versus electromyography was comparable (98.1% vs 97.4%). The cost of the laryngeal ultrasound per operation was less than electromyography ($82 vs $454).

CONCLUSION

Laryngeal ultrasound has a similar detection accuracy to electromyography during intraoperative nerve monitoring. Apart from being a cheaper alternative, laryngeal ultrasound may be useful when there is unexplained loss of electromyography signals during surgery and may play a role in the intraoperative nerve monitoring troubleshooting algorithm.

Natural Course of Unilateral Vocal Fold Paralysis and Optimal Timing of Permanent Treatment

Importance

Permanent surgical treatment for unilateral vocal fold paralysis (UVFP) should be performed when further neural recovery is improbable. Conservative delay of the surgical procedure may cause unnecessary deterioration of the patient's quality of life. Knowledge of the natural course of UVFP is important for better management and counseling.

Objective

To evaluate the natural course of UVFP, focusing on the recovery time according to the injury level to assess the optimal timing for permanent surgical intervention.

Design, Setting, and Participants

This retrospective case series enrolled 1264 patients with UVFP who visited the voice clinic of Seoul National University Hospital, Seoul, Korea, from November 1, 2005, through December 31, 2016. Medical records and stroboscopic video images were reviewed to obtain data on demographic characteristics, vocal fold movement, onset and recovery time, follow-up duration, and cause. Cases of UVFP were classified into 5 groups based on the location of injury: distal to the thyroid level, thyroid level, esophagus and mediastinum level, heart and lung level, and proximal to the thorax level. Data analysis was performed from January 23, 2018, to May 21, 2018.

Main Outcomes and Measures

Recovery of vocal fold movement defined as more than vocal fold twitching confirmed by stroboscopy video images, estimated injury level, and start time of recovery. The recovery time was analyzed according to age, sex, paralytic side, and 5 injury levels.

Results

Of 1264 eligible patients with UVFP (655 [51.8%] male; median age, 56 years [range, 1-90 years]), 208 had evidence of recovery with the recovery time relatively accurate. The maximum recovery time for the group with distal to the thyroid-level injury was 120 days; the group with thyroid-level injury, 157 days; the group with esophagus and mediastinum-level injury, 244 days; the group with heart and lung-level injury, 328 days; and the group with proximal to the thorax-level injury, 333 days with the exception of 1 outlier value (482 days). Recovery time did not differ according to age, sex, or paralytic side. As distance between the vocal fold and injury level increased, the maximum recovery time increased, plateauing at 1 year. Among the patients who showed recovery of the vocal fold movement, most patients with injuries distal to or at the level of the thyroid recovered within 6 months, whereas those with injury more distant from the vocal fold recovered within approximately 1 year.

Conclusions and Relevance

A linear association between injury level and maximum recovery time was observed. The findings suggest that the decision to proceed with permanent phonosurgical treatment should be based on the level of injury associated with UVFP.

Yield of Imaging to Evaluate Unilateral Vocal Fold Paralysis of Unknown Etiology

OBJECTIVES/HYPOTHESIS

To identify the incidence and nature of positive findings on imaging studies ordered for evaluation of unilateral vocal fold paralysis (UVFP) of unknown etiology, to analyze these findings based on laterality, and to examine the use of the expanded-field computed tomography (CT) neck protocol in this evaluation.

STUDY DESIGN

Retrospective review.

METHODS

A total of 145 patients from 2000 to 2018 with UVFP of unknown etiology were studied. Data on imaging studies ordered, laterality of paralysis, and significant positive results were studied. An expanded-field CT neck protocol that included the entire course of the vagus and recurrent laryngeal nerves was instituted during the study period.

RESULTS

A total of 20.7% of patients had an etiology for paralysis identified on imaging. Malignancies comprised the majority of findings overall (19/30), whether in the chest (12/18) or the neck (7/12). Etiology was more often found in the chest for left-sided paralysis (15/21) and in the neck for right-sided paralysis (6/9). In 26 patients who underwent both expanded-field CT neck and CT chest, no findings related to the UVFP were seen on CT chest that were not captured by expanded-field CT neck.

CONCLUSIONS

This is one of the largest retrospective studies examining the incidence of positive findings on imaging studies for evaluation of UVFP of unknown etiology. Imaging in one of five patients with UVFP of unknown etiology will reveal a causative lesion, most often malignant. Left-sided paralysis tends to localize to the chest, and right-sided paralysis to the neck. Expanded-field CT neck may allow practitioners to forego dedicated CT chest in evaluation of UVFP.

LEVEL OF EVIDENCE

4 Laryngoscope, 131:1840-1844, 2021.

Immediate and partial neural dysfunction after thyroid and parathyroid surgery: Need for recognition, laryngeal exam, and early treatment

BACKGROUND

Laryngeal dysfunction after thyroid and parathyroid surgery requires early recognition and a standardized approach for patients that present with voice, swallowing, and breathing issues. The Endocrine Committee of the American Head and Neck Society (AHNS) convened a panel to define the terms "immediate vocal fold paralysis" and "partial neural dysfunction" and to provide clinical consensus statements based on review of the literature, integrated with expert opinion of the group.

METHODS

A multidisciplinary expert panel constructed the manuscript and recommendations for laryngeal dysfunction after thyroid and parathyroid surgery. A meta-analysis was performed using the literature and published guidelines. Consensus was achieved using polling and a modified Delphi approach.

RESULTS

Twenty-two panelists achieved consensus on five statements regarding the role of early identification and standardization of evaluation for patients with "immediate vocal fold paralysis" and "partial neural dysfunction" after thyroid and parathyroid surgery.

CONCLUSION

After endorsement by the AHNS Endocrine Section and Quality of Care Committee, it received final approval from the AHNS Council.

A prospective study evaluating the feasibility and accuracy of very early postoperative translaryngeal ultrasonography in the assessment of vocal cord function after neck surgery

BACKGROUND

Early recognition of postoperative vocal cord palsy enhances postoperative care. Translaryngeal ultrasonography can assess vocal cord function accurately and noninvasively, but it is unclear whether it is feasible or accurate when done immediately after extubation in the recovery room owing to possible interference from laryngeal swelling. This study assessed the feasibility and accuracy of translaryngeal ultrasonography in this setting.

METHODS

Consecutive patients undergoing neck operations were subjected to translaryngeal ultrasonography and flexible direct laryngoscopy 1 day before and day 7 after thyroidectomy and parathyroidectomy. Translaryngeal ultrasonography was performed early in the recovery room immediately after extubation in the operating room. A standardized assessment protocol was used. Patient parameters were compared between those with assessable and unassessable vocal cords.

RESULTS

Sixty-five patients (91 recurrent laryngeal nerves-at-risk) were analyzed after excluding 2 male patients who failed preoperative translaryngeal ultrasonography. Fifty-six patients underwent thyroidectomy and 9 parathyroidectomy. The median age (range) was 57 (46-69); 44 (68%) were women. Sixty-one patients (94%) had assessable bilateral vocal cords on translaryngeal ultrasonography in the recovery room. Translaryngeal ultrasonography in the recovery room findings corresponded completely with day-7 findings on direct laryngoscopy. Long operative time was associated with nonassessable vocal cords on translaryngeal ultrasonography in the recovery room (P = .026).

CONCLUSION

Very early postoperative translaryngeal ultrasonography in the recovery room after neck surgery is highly feasible and accurate. Long operative time may hinder the use of translaryngeal ultrasonography in the recovery room.

[Update on vocal fold augmentation]

Unilateral vocal fold palsy is a frequent cause of hoarseness. In the presence of glottis closure insufficiency, the effectiveness of conservative voice therapy is often limited and phonosurgery may be indicated. Injection laryngoplasty is effective for correction of insufficiency. Early intervention during the first 6 months after diagnosis is desired to avoid subsequent insufficient endogenous compensation. Particularly patients with glottic closure insufficiency ≤2 mm in stroboscopy may benefit from this procedure. With appropriate patient selection, duration of the effect exceeding 12 months has been described for hyaluronic acid, calcium hydroxylapatite, and autologous fat. Due to rare complications such as allergic swelling at the injection site, regular laryngoscopic monitoring and observation for two nights after injection are recommended. The voice must only be rested for a few hours.