Elsevier

Surgery

Volume 166, Issue 3, September 2019, Pages 369-374
Surgery

Endocrine
Complete and incomplete recurrent laryngeal nerve injury after thyroid and parathyroid surgery: Characterizing paralysis and paresis

https://doi.org/10.1016/j.surg.2019.05.019Get rights and content

Abstract

Background

Injury of the recurrent laryngeal nerve and consequent disorder of vocal fold movement is a typical complication in thyroid and parathyroid surgery. During postoperative laryngoscopy we observed not only a complete standstill (vocal fold paralysis), but also a hypomobility (paresis). In this prospective study, we investigated the difference in incidence and prognosis as well as risk-factors, intraoperative neuromonitoring, and symptoms between vocal fold paralysis and vocal fold paresis.

Methods

Data were prospectively collected and analyzed in a single high-volume thyroid center between 2012 and 2016. Vocal fold paresis was defined as hypomobility in abduction or adduction, a reduction in range and speed of vocal fold movement. Vocal fold paralysis was defined as asymmetry and missing purposeful vocal fold movement.

Results

The study included 4,707 surgeries and 7,992 at-risk nerves at risk. Vocal fold paralysis was diagnosed in 374 patients (4.68% of 7,992 nerves at risk) and vocal fold paresis in 114 patients (1.43%). Exclusively in the paralysis group, 36 patients (0.45%) developed permanent loss of vocal fold function (P < .001). In follow-up, vocal fold paresis patients regain normal vocal fold function significantly earlier than vocal fold paralysis (mean duration: 6.96 ± 6.506 vs 10.77 ± 7,827 weeks) and presented with significantly less symptoms like hoarseness, diplophonia, dysphagia, and dyspnea (68.8% vs 95.9 %). In intraoperative neuromonitoring, vocal fold paresis showed a significantly higher postresectional N. vagus amplitude than vocal fold paralysis patients (0.349 mV vs 0.114 mV, P < .001).

Conclusion

After thyroidectomy, vocal fold paresis must be distinguished from vocal fold paralysis and should be implemented as a separate outcome parameter in the postoperative quality assessment.

Introduction

Paralysis of the recurrent laryngeal nerve (RLN) is a typical and occasionally permanent complication after thyroid surgery affecting patient’s quality of life. The incidence of temporary (rehabilitation within 6 months) and permanent paralysis ranges from 1.4 to 38 and 0.3 to 3 percent respectively.1, 2, 3, 4, 5, 6, 7, 8 Immobility of the vocal fold (VF) is defined as the absence of purposeful motion and is categorized as VF paralysis.9, 10 Recently a reduced but still visible mobility of the VF (in contrast to paralysis) gained attention in laryngological research owing to improved methods of diagnosis.11, 12 This entity was first described by Koufman et al in 50 patients with symptoms such as dysphonia, vocal fatigue, and diplophonia.13

Hypomobility of the VF after thyroidectomy has still not been defined as an outcome parameter and has not been implemented in early routine postoperative evaluation, yet VF hypomobility was mentioned in a previous manuscript of our institution.14 However, for patients and for surgeons it is of major importance to distinguish between complete immobility (paralysis), incomplete or reduced mobility (paresis), and regular movement of the VF. The aim of the present study was to prospectively investigate the, incidence, rate of recovery of VF paresis in comparison to VF paralysis after thyroid and parathyroid surgery and to evaluate contributing risks factors for these complications. Furthermore, intraoperative neuromonitoring data of surgeries and symptoms of VF paresis patients were compared with those with VF paralysis.

Section snippets

Methods

Data were prospectively collected and analyzed in a single high-volume thyroid center with the focus on postoperative VF function distinguishing paralysis, paresis, and regular mobility. These entities were recorded as separate outcome parameter in our database. Ethical approval was granted by the KAV review board (EK 15-128-VK). In the study, 4,715 patients (female and male) were prospectively included. All patients underwent thyroid and parathyroid surgery between January 2012 until December

Results

In the study, 4,707 patients were surgically treated for thyroid and parathyroid disease with 7,992 NAR; 3,495 were women and 1,212 men. Patients received bilateral surgery (n = 3,302) or unilateral surgery (n = 1,388), and 17 were sole resections of thyroid isthmus or pyramidal lobe.

Diagnoses were distributed as follows: malignant diagnosis in 641 patients (14.85%), Graves disease in 374 (9.12%), recurrent disease in 301 (5.18%), and hyperparathyroidism in 245 (4.09%) patients. The remaining

Discussion

The aim of this study was to investigate incidence and prognosis of VF hypomobility (ie, paresis) versus complete VF immobility (ie, paralysis) after thyroid and parathyroid surgery in routine postoperative laryngoscopy. The discrepancy between these 2 diagnoses has not been evaluated as an independent parameter after thyroid surgery to the best of our knowledge. There was a significant difference between the 2 groups in the rate of recovery, time to restitution, and IONM vagal nerve amplitude

Funding/Support

The authors have indicated that they have no conflicts of interest (or funding) regarding the content of this article.

Conflict of interest/Disclosure

All authors declare no conflict of interest.

Acknowledgments

We thank Paul Haller and Nikolaus Pfisterer for their contribution to the statistical analysis as well as Malwina Jarosz for data acquisition.

References (34)

  • J.-P. Jeannon et al.

    Diagnosis of recurrent laryngeal nerve palsy after thyroidectomy: Asystematic review

    Int J Clin Pract

    (2009)
  • N.J. Hayward et al.

    Recurrent laryngeal nerve injury in thyroid surgery: A review

    ANZ J Surg

    (2013)
  • T.-J. Fang et al.

    Quality of life measures and predictors for adults with unilateral vocal cord paralysis

    Laryngoscope

    (2008)
  • C. Bures et al.

    Late-onset palsy of the recurrent laryngeal nerve after thyroid surgery

    Br J Surg

    (2014)
  • C. Bures et al.

    Guidelines for complications after thyroid surgery: Pitfalls in diagnosis and advices for continuous quality improvement

    Eur Surg Acta Chir Austriaca

    (2014)
  • A. Bergenfelz et al.

    Risk of recurrent laryngeal nerve palsy in patients undergoing thyroidectomy with and without intraoperative nerve monitoring

    Br J Surg

    (2016)
  • R. Schneider et al.

    Postoperative vocal fold palsy in patients undergoing thyroid surgery with continuous or intermittent nerve monitoring

    Br J Surg

    (2015)
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