Utility of injection laryngoplasty in the management of post-thyroidectomy vocal cord paralysis

Analysis of the Outcomes of Immediate Recurrent Laryngeal Nerve Reconstruction During Thyroid Surgery for Prevention of Vocal Fold Paralysis

BACKGROUND

Recurrent laryngeal nerve (RLN) injury and the resulting paralysis is the most common and known complication of thyroid surgery. Several surgical techniques, such as medialization thyroplasty with or without arytenoid adduction and injection laryngoplasty, have been developed to treat RLN injury, but these procedures have specific limitations and complications. In this study, we present the outcomes for our patients who underwent immediate RLN reconstruction during thyroid surgery by analyzing both subjective and objective outcomes.

METHODS

A retrospective study was conducted for patients who underwent total or subtotal thyroidectomy between May 2012 and March 2020. Among them, patients who underwent immediate RLN reconstruction due to unilateral RLN injury were followed for at least 12 months. The voice perceptual evaluation, acoustic analysis, voice range profile, and Voice Handicap Index (VHI) scores were obtained preoperatively, 1 month, 6 months, and 12 months after surgery.

RESULTS

Among the 11 patients, 6 patients (54.5%) underwent direct anastomosis, and 5 patients (45.5%) underwent nerve grafts using ansa cervicalis and great auricular nerve. The grade and breathiness in the GRBAS (grade, roughness, breathiness, asthenia, and strain) scale and jitter item showed significant improvement at 12 months postoperatively, and although not statistically significant, the rest of the items also tended to improve. The total, functional, and physical scores on VHI improved significantly at 12 months postoperatively. Moreover, when comparing the voice analysis of the direct anastomosis group and the nerve graft group, there was no significant difference between the groups in objective and subjective results.

CONCLUSION

Immediate RLN reconstruction demonstrated significant voice improvement postoperatively, and reconstructing the nerve immediately and combining follow-up treatment in the event of RLN injury will greatly help patients improve their long-term voice outcomes.

Office-Based Structural Autologous Fat Injection Laryngoplasty for Unilateral Vocal Fold Paralysis

Unilateral vocal fold paralysis (UVFP) is a common cause of incomplete glottic closure, leading to significant somatic and social disabilities. Office-based autologous fat injection laryngoplasty (AFIL) has been proposed as an effective treatment for glottic insufficiency but has not been well-studied for UVFP. We enrolled 23 patients who underwent office-based structural AFIL due to unilateral vocal paralysis at our institution between February 2021 and January 2022. In the procedure, autologous fat was harvested and injected into the vocal fold under the guidance of flexible digital endoscopy for structural fat grafting. The voice handicap index-10 (VHI-10) score and perceptual voice measurements were collected before the operation, 2 weeks postoperatively, and 3 months postoperatively. Twenty-two patients were followed-up for at least 3 months. The VHI-10 score improved significantly from 29.65 ± 8.52 preoperatively to 11.74 ± 7.42 at 2 weeks (p < 0.0001) and 5.36 ± 6.67 at 3 months (p < 0.0001). Significant improvements in grades of dysphonia (p < 0.0001), breathiness (p < 0.0001), and asthenia (p = 0.004) were also noted at 3 months postoperatively when perceptual measurements were investigated. Office-based structural AFIL is an effective treatment for improving voice-related disability for UVFP patients.

Management of Unilateral Vocal Fold Paralysis after Thyroid Surgery with Injection Laryngoplasty: State of Art Review

Background

Unilateral vocal fold paralysis (UVFP) after thyroid surgery often leads to significant morbidity including dysphonia, dysphagia, and aspiration. Injection laryngoplasty (IL) is an effective treatment of UVFP with numerous readily available materials. However, few studies focus on IL for UVFP following thyroidectomy.

Objectives

This review aims to critically review current literature to determine the timing, materials, methods and outcomes of IL for UVFP after thyroid surgery.

Type of Review

Literature review.

Methods

A literature review was performed using the Pubmed, Medline and EMBASE databases. All relevant articles published in English addressing the effect of IL in post thyroid surgery related UVFP were analyzed. Studies using IL for UVFP of multiple etiologies were excluded. Meta-analysis was conducted using fixed and random effect model.

Results

Five original studies were identified, including 214 patients received IL for UVFP following thyroid surgery. Two studies injected autologous fat via direct suspension laryngoscope under general anesthesia, while the other 3 studies injected polyacrylamide, hyaluronic acid, and polymethyl methacrylate from cricothyroid membrane under local anesthesia. All 5 studies reported improved voice outcomes of IL for post-thyroidectomy UVFP. Meta-analysis showed MPT increased for 3.18 s (95% CI: 2.40–3.96, fix effect model) after IL. Another common acoustic parameter, jitter (%) also improved for 1.46 (95% CI: 0.73–2.19, random effects model) after IL for post-thyroidectomy UVFP.

Conclusions

This review supported that IL can improve the voice outcome for post-thyroidectomy UVFP. Autologous fat remains a good augmentation material with a potential longer lasting effect. More research and long-term surveys are needed to document the safety and longevity of other synthetic materials.

Care and Management of Voice Change for Thyroid Surgery: Korean Society of Laryngology, Phoniatrics and Logopedics Clinical Practice Guideline

Voice change is a common complaint after thyroid surgery and has significant impacts on quality of life. The Korean Society of Laryngology, Phoniatrics, and Logopedics set up a task force team to establish guideline recommendations on education, care, and management related to thyroid surgery. The guideline recommendations include preoperative voice education, management of anticipated voice change during surgery, and comprehensive voice care after thyroid surgery, including in-depth information and up-to-date knowledge based on validated literature. The committee constructed 14 key questions (KQ) in three categories: preoperative (KQ1-2), intraoperative (KQ 3-8), and postoperative (KQ 9-14) management and developed 18 evidence-based recommendations. The Delphi survey reached an agreement on each recommendation. Detailed evidence profiles are presented for each recommendation. The level of evidence for each recommendation is classified into high, moderate, and low-quality. The recommendation's strengths are adjusted to consider the level of evidence resulting in the recommendation and are divided into strong and weak. The guidelines are primarily targeted toward physicians who treat thyroid surgery patients and speech-language pathologists participating in patient care. These guidelines will also help primary care physicians, nurses, healthcare policymakers, and patients improve their understanding of voice changes and voice care after thyroid surgery.

Prognostic Indicators of Non-Transection Nerve Injury and Vocal Fold Motion Impairment After Thyroid Surgery - Correlation Between Intraoperative Neuromonitoring Findings and Perioperative Voice Parameters

OBJECTIVES

In patients with recurrent laryngeal nerve (RLN) injury after thyroid surgery, unrecovered vocal fold motion (VFM) and subjective voice impairment cause extreme distress. For surgeons, treating these poor outcomes is extremely challenging. To enable early treatment of VFM impairment, this study evaluated prognostic indicators of non-transection RLN injury and VFM impairment after thyroid surgery and evaluated correlations between intraoperative neuromonitoring (IONM) findings and perioperative voice parameters.

METHODS

82 adult patients had postoperative VFM impairment after thyroidectomy were enrolled. Demographic characteristics, RLN electromyography (EMG), and RLN injury mechanism were compared. Multi-dimensional voice program, voice range profile and Index of voice and swallowing handicap of thyroidectomy (IVST) were administered during I-preoperative; II-immediate, III-short-term and IV-long-term postoperative periods. The patients were divided into R/U Group according to the VFM was recovered/unrecovered 3 months after surgery. The patients in U Group were divided into U1/U2 Group according to total IVST score change was <4 and ≥4 during period-IV.

RESULTS

Compared to R Group (42 patients), U Group (38 patients) had significantly more patients with EMG >90% decrease in the injured RLN (p<0.001) and thermal injury as the RLN injury mechanism (p=0.002). Voice parameter impairments were more severe in U Group compared to R Group. Compared to U1 group (19 patients), U2 Group (19 patients) had a significantly larger proportion of patients with EMG decrease >90% in the injured RLN (p=0.022) and thermal injury as the RLN injury mechanism (p=0.017). A large pitch range decrease in period-II was a prognostic indicator of a moderate/severe long-term postoperative subjective voice impairment.

CONCLUSION

This study is the first to evaluate correlations between IONM findings and voice outcomes in patients with VFM impairment after thyroid surgery. Thyroid surgeons should make every effort to avoid severe type RLN injury (e.g., thermal injury or injury causing EMG decrease >90%), which raises the risk of unrecovered VFM and moderate/severe long-term postoperative subjective voice impairment. Using objective voice parameters (e.g., pitch range) as prognostic indicators not only enables surgeons to earlier identify patients with low voice satisfaction after surgery, and also enable implementation of interventions sufficiently early to maintain quality of life.

Recovery of Voice After Reconstruction of the Recurrent Laryngeal Nerve and Adjuvant Nimodipine

Background

Transection injury to the recurrent laryngeal nerve (RLN) has been associated with permanent vocal fold palsy, and treatment has been limited to voice therapy or local treatment of vocal folds. Microsurgical repair has been reported to induce a better function. The calcium channel antagonist nimodipine improves functional recovery after experimental nerve injury and also after cranial nerve injury in patients. This study aims to present voice outcome in patients who underwent repair of the RLN and received nimodipine during regeneration.

Methods

From 2002–2016, 19 patients were admitted to our center with complete unilateral injury to the RLN and underwent microsurgical repair of the RLN. After nerve repair, patients received nimodipine for 2–3 months. Laryngoscopy was performed repeatedly up to 14 months postoperatively. The Voice Handicap Index (VHI) was administered, and patients’ maximum phonation time (MPT) was recorded during the follow-up.

Results

All patients recovered well after surgery, and nimodipine was well tolerated with no dropouts. None of the patients suffered from atrophy of the vocal fold, and some patients even showed a small ab/adduction of the vocal fold on the repaired side with laryngoscopy. During long-term follow-up (>3 years), VHI and MPT normalized, indicating a nearly complete recovery from unilateral RLN injury.

Conclusions

In this cohort study, we report the results of the first 19 consecutive cases at our center subjected to reconstruction of the RLN and adjuvant nimodipine treatment. The outcome of the current strategy is encouraging and should be considered after iatrogenic RLN transection injuries.

Does the recurrent laryngeal nerve recover function after initial dysfunction in patients undergoing thyroidectomy?

Objective

Total thyroidectomy with or without central compartment dissection is the treatment of choice for thyroid carcinoma. Extensive dissection along the recurrent laryngeal nerve (RLN) can lead to vocal cord fixity and hoarseness even without nerve sacrifice. Recovery rates after surgery for thyroid cancers have not been well documented. The aim of the study is to analyze the incidence of vocal cord palsy (VCP) and its recovery rates in patients operated for thyroid cancers. Methodology: We performed a retrospective study on prospectively collected data in 152 thyroidectomy patients with 254 RLNs at risk. All patients underwent a laryngoscopic examination to document vocal cord function in the immediate postoperative period and on subsequent follow-up. Incidence of VCP, recovery rates, univariate and multivariate analysis to identify risk factors for permanent VCP were calculated using binary logistic regression.

Results

In our study, 28% patients underwent redo surgeries and 74% patients had dissection of the central compartment. The immediate postoperative RLN palsy rate was 11.2%, with a palsy rate of 9% and 16.2% in the per primum and redo surgery cohorts. On follow-up, there was complete recovery of VCP in 66.7% of these nerves. The incidence of permanent RLN palsy was 3.9%. The mean time to recovery was 9.6 months.

Conclusion

Vocal cord dysfunction recovered in most patients in this high-risk cohort. There was a significant recovery even in the redo surgery group and a policy of watchful waiting is recommended in the absence of severe symptoms.

Level of Evidence

III.

A long-term comparative prospective study between reinnervation and injection laryngoplasty

OBJECTIVES

This study compared and assessed long-term voice outcomes when thyroidectomy-related unilateral vocal fold paralysis (VFP) was managed using injection laryngoplasty (IL) and recurrent laryngeal nerve reinnervation (RLNR).

STUDY DESIGN

Prospective clinical study.

METHODS

A prospective clinical trial was performed from March 2005 to January 2016 at Soonchunhyang University Bucheon Hospital (Bucheon, South Korea). Nineteen patients who underwent ansa cervicalis to RLNR or direct reinnervation, and 43 patients who underwent IL to treat thyroidectomy-related unilateral VFP, were enrolled.

RESULTS

All voice parameters exhibited statistically significant improvement 12 months post-IL, which persisted for 24 and 36 months (P < 0.05). However, at 36 months post-IL, some voice parameters had deteriorated relative to the values at 24 months post-IL. After RLNR, all voice parameters exhibited statistically significant improvement after 12 months, and the improvements remained stable until 36 months postsurgery without deterioration of voice parameters (P < 0.05). At 36 months, RLNR provided better voice results than IL (P < 0.05).

CONCLUSION

Both RLNR and IL yielded statistically significant voice improvements at 36 months postoperatively. However, after 36 months, RLNR provided better results than IL.

LEVEL OF EVIDENCE

3. Laryngoscope, 1893-1897, 2018.

Speech therapy after thyroidectomy

Common complaints of patients who have received thyroidectomy include dysphonia (voice dysfunction) and dysphagia (difficulty swallowing). One cause of these surgical outcomes is recurrent laryngeal nerve paralysis. Many studies have discussed the effectiveness of speech therapy (e.g., voice therapy and dysphagia therapy) for improving dysphonia and dysphagia, but not specifically in patients who have received thyroidectomy. Therefore, the aim of this paper was to discuss issues regarding speech therapy such as voice therapy and dysphagia for patients after thyroidectomy. Another aim was to review the literature on speech therapy for patients with recurrent laryngeal nerve paralysis after thyroidectomy. Databases used for the literature review in this study included, PubMed, MEDLINE, Academic Search Primer, ERIC, CINAHL Plus, and EBSCO. The articles retrieved by database searches were classified and screened for relevance by using EndNote. Of the 936 articles retrieved, 18 discussed "voice assessment and thyroidectomy", 3 discussed "voice therapy and thyroidectomy", and 11 discussed "surgical interventions for voice restoration after thyroidectomy". Only 3 studies discussed topics related to "swallowing function assessment/treatment and thyroidectomy". Although many studies have investigated voice changes and assessment methods in thyroidectomy patients, few recent studies have investigated speech therapy after thyroidectomy. Additionally, some studies have addressed dysphagia after thyroidectomy, but few have discussed assessment and treatment of dysphagia after thyroidectomy.

The usefulness of the transcricothyroid injection laryngoplasty via contralateral paramedian approach

OBJECTIVE

Several laryngeal injection techniques are technically difficult and have limitations. In this study, we modified a transcricothyroid approach for injections to enhance needle visualization during procedures. The objective of this study was to investigate the efficacy of this alternative injection technique.

METHODS

We performed a retrospective analysis of 51 patients who had undergone injection laryngoplasty for unilateral vocal paralysis between March 2014 and February 2015. In total, 17 patients underwent a transcricothyroid injection laryngoplasty via the contralateral paramedian approach (ILC) and 34 patients underwent transcricothyroid injection laryngoplasty via the conventional approach (ipsilateral approach, ILI). Acoustic analyses, aerodynamic analyses, voice handicap index (VHI), and GRBAS scale were assessed pre-operatively and at 2 weeks and 3 months postoperatively.

RESULTS

From our acoustic and aerodynamic analyses, jitter, shimmer, noise-to-harmonic ratio (NHR), maximum phonation time (MPT), and mean flow rate (MFR) were all significantly improved in both groups after injection. VHI and GRBAS scales also improved postoperation. There were no significant differences between the pre-operative and postoperative subjective and objective parameters between both groups. The total injection volume used on the ILI group was larger than the volume given to the ILC group.

CONCLUSION

The transcricothyroid injection laryngoplasty via the contralateral paramedian approach is potentially more beneficial to performing injection laryngoplasty under local anesthesia. One important advantage of this approach to conventional approaches is its enhanced visualization of the needle during procedures.

Glass ionomer application for vocal fold augmentation: Histopathological analysis on rabbit vocal fold

OBJECTIVES/HYPOTHESIS

The aim of this study was to investigate the use of glass ionomer cement (GIC) as an injection material for vocal fold augmentation and to evaluate the biocompatibility of the material.

STUDY DESIGN

Ten adult New Zealand rabbits were used.

METHODS

Under general anesthesia, 0.1-cc GIC was injected to one vocal fold and the augmentation of vocal fold was observed. No injection was applied to the opposite side, which was accepted as the control group. The animals were sacrificed after 3 months and the laryngeal specimens were histopathologically evaluated.

RESULTS

The injected and the noninjected control vocal folds were analyzed. The GIC particles were observed in histological sections on the injected side, and no foreign body giant cells, granulomatous inflammation, necrosis, or marked chronic inflammation were detected around the glass ionomer particles. Mild inflammatory reactions were noticed in only two specimens. The noninjected sides of vocal folds were completely normal.

CONCLUSION

The findings of this study suggest that GIC is biocompatible and may be further investigated as an alternative injection material for augmentation of the vocal fold. Further studies are required to examine the viscoelastic properties of GIC and the long-term effects in experimental studies.

LEVEL OF EVIDENCE

NA.

Long-term efficacy of primary intraoperative recurrent laryngeal nerve reinnervation in the management of thyroidectomy-related unilateral vocal fold paralysis

CONCLUSION

Primary intraoperative recurrent laryngeal nerve (RLN) reinnervation techniques demonstrated significant voice improvement at 24 months postoperatively and could be an effective alternative treatment for thyroidectomy-related permanent unilateral vocal fold paralysis (VFP).

OBJECTIVES

To assess the long-term efficacy of intraoperative RLN reinnervation techniques in the management of thyroidectomy-related unilateral VFP.

METHODS

A prospective study was conducted from January 2008 to June 2012 at Soonchunhyang University Bucheon Hospital. Nineteen patients who underwent RLN reinnervation with either direct reinnervation (neurorrhaphy) or ansa cervicalis to RLN (ansa-RLN) anastomosis and completed subjective and objective voice measurement over a 1-year follow-up period were included in this study.

RESULTS

The causes of VFP were cancer involving the RLN (68.4%, 13/19) and iatrogenic nerve transection (31.5%, 6/19). Reinnervation techniques were direct neurorrhaphy (63.2%, 12/19) and ansa-RLN anastomosis (36.8%, 7/19). Subjective parameters such as the Voice Handicap Index (VHI), posterior glottic closure, and mucosal wave demonstrated significant improvement 6 months postoperatively, and the majority of parameters remained stable up to 24 months (p < 0.05). Objective parameters, such as maximum phonation time (MPT), jitter, shimmer, and the harmonics-to-noise ration (HNR), demonstrated significant improvement at 12 months and most remained stable at 24 months (p < 0.05).

Types and timing of therapy for vocal fold paresis/paralysis after thyroidectomy: a systematic review and meta-analysis

OBJECTIVES

To perform a systematic literature review to evaluate the type and timing of therapy for vocal fold paresis/paralysis after thyroidectomy and develop a primary decision-making pathway.

STUDY DESIGN

Meta-analysis.

METHODS

Four databases and one journal were searched using the key words of "thyroidectomy," "vocal cord paresis/paralysis," and "therapy." Study quality was evaluated using the Cochrane Collaboration's risk of bias tools. Data regarding type and timing of therapy were extracted from 39 articles. Odds ratios (ORs), relative risk (RR), 95% confidence interval, and heterogeneity were recorded. Logistic regression analysis was performed to determine the relationships between timing and OR/RR.

RESULTS

Among the 13 studies investigating unilateral paresis/paralysis, five focused on early therapy (0-6 months). In these studies, the OR for clinical heterogeneity was significantly higher after neurolysis than after injection laryngoplasty and voice training (Q = 17.002, I(2) = 78%, P = 0.000), and the RR for heterogeneity was significantly higher after injection laryngoplasty at ≥12 months than <12 months (Q = 9.984, I(2) = 89.9%, P = 0.002). In the 26 studies that investigated bilateral paresis/paralysis, the OR for heterogeneity was significantly higher for bilateral posterior cordectomy than for endolaryngeal laterofixation (Q = 3.510, I(2) = 71.5%, P = 0.061) and laser arytenoidectomy with posterior cordectomy (Q = 2.90, I(2) = 65.6%, P = 0.088).

CONCLUSIONS

For unilateral vocal fold paresis/paralysis after thyroidectomy, we recommend absorbable mass injection laryngoplasty, voice training, and neurolysis during the first 12 months but laryngeal reinnervation after 12 months. For bilateral vocal fold paresis/paralysis, we recommend early laterofixation and combined laser arytenoidectomy with posterior cordectomy after 12 months.

Office-based injection laryngoplasty for the management of unilateral vocal fold paralysis

OBJECTIVE

Office-based injection laryngoplasty (OBIL) is a common method of addressing glottal insufficiency. This retrospective chart review identifies the demongraphics, laterality, technique, success rate, injectates, and complications of OBIL performed over a 3-year period at a single institution.

STUDY DESIGN

Retrospective chart review.

METHODS

All OBILs performed for the management of UVFP by the senior author over 3 years (2007-2009) were identified from billing records. The age, gender, laterality, underlying disease process, augmentation material, route of injection, and complications were recorded.

RESULTS

Eighty-two OBILs were attempted on 57 patients. The most common route of access was transoral (85.6%). All OBILs were able to be completed. Injectates used were hyaluronic acid derivatives (57.3%), calcium hydroxyapatite (16%), and Cymmetra (16.5%). Three complications (3.7%) occurred. Thirty percent of patients ultimately elected for thyroplasty or ansa reinnervation, 22% found their condition to self-resolve, 14% died, and 25% were lost to follow-up.

CONCLUSIONS

Using a variety of approaches, OBIL is possible in almost all patients. The single surgeon transoral route using a rigid angled telescope and curved injection needle was the most commonly used approach. Multiple injectates can be used and have good safety records. The final disposition of patients may be variable and warrants further investigation.

Functional regeneration of recurrent laryngeal nerve injury during thyroid surgery using an asymmetrically porous nerve guide conduit in an animal model

BACKGROUND

Vocal cord paralysis (VCP) caused by recurrent laryngeal nerve (RLN) damage during thyroidectomy commonly results in serious medico-legal problems. The purpose of this study was to evaluate the usefulness of an asymmetrically porous polycaprolactone (PCL)/Pluronic F127 nerve guide conduit (NGC) for functional regeneration in a RLN injury animal model.

METHODS

A biodegradable, asymmetrically porous PCL/F127 NGC with selective permeability was fabricated for use in this study. A 10-mm segment of left RLN was resected in 28 New Zealand white rabbits, and then an asymmetrically porous NGC or a nonporous silicone tube was interposed between both stumps and securely fixed. Vocal cord mobility was endoscopically evaluated at one, four, and eight weeks postoperatively. Nerve growth through NGCs was assessed by toluidine blue staining, and thyroarytenoid (TA) muscle atrophy was evaluated by hematoxylin and eosin staining. Immunohistochemical stainings for acetylcholinesterase (AchE), anti-neurofilament (NF), and anti-S100 protein were also conducted, and transmission electron microscopy (TEM) was used to evaluate functional nerve regeneration.

RESULTS

At eight weeks postoperatively, endoscopic evaluations showed significantly better recovery from VCP in the asymmetrically porous PCL/F127 NGC group (6 of 10 rabbits) than in the silicone tube group (1 of 10 rabbits). Continued nerve growth on the damaged nerve endings was observed with time in the asymmetrically porous PCL/F127 NGC-interposed RLNs. TA muscle dimensions and AchE expressions in TA muscle were significantly greater in the asymmetrically porous PCL/F127 NGC group than in the silicone tube group. Furthermore, immunohistochemical staining revealed the expression of NF and S100 protein in the regenerated nerves in the asymmetrically porous PCL/F127 NGC group at eight weeks postoperatively, and at this time, TEM imaging showed myelinated axons in the regenerated RLNs.

CONCLUSION

The study shows that asymmetrically porous PCL/F127 NGC provides a favorable environment for RLN regeneration and that it has therapeutic potential for the regeneration of RLN damage.

Prevention of complications in transaxillary single-incision robotic thyroidectomy

BACKGROUND

Transaxillary robotic thyroidectomy, developed by the Yonsei University group from Seoul, Korea, is a new approach that eliminates the need for a cervical incision. Originally, this technique was performed using a two-incision technique (ipsilateral axilla and anterior chest wall). More recently, the chest wall incision is being eliminated and a less invasive robotic thyroid procedure is being performed through a single axillary incision.

SUMMARY

The complexity of this new technique introduces the potential for new complications particularly during the initial learning curve that are not routinely or previously associated with conventional open thyroidectomy. This article will aide surgeons in overcoming the learning curve of transaxillary single-incision robotic thyroidectomy (TSI-RT), giving a detailed explanation of the robotic surgical procedure, the possible complications, and complication management.

CONCLUSIONS

If surgeons have mastery of the multiple steps of the robotic surgical procedure and a good understanding of possible complications and how to prevent them, TSI-RT can be performed safely and offers numerous advantages over multi-incision robotic thyroidectomy as well as conventional open thyroidectomy.

Aerodynamic evaluation of the postthyroidectomy voice

OBJECTIVES/HYPOTHESES

Changes in vocal function before and after thyroidectomy were examined using aerodynamic and related assessments. Laryngeal airway resistance (R(law)) and phonation threshold pressure (PTP) were hypothesized to be sensitive to changes in laryngeal function that may occur after thyroidectomy separate from changes that may occur from endotracheal intubation alone.

STUDY DESIGN

Prospective longitudinal clinical trial with comparison group.

METHODS

Eighty patients were evaluated preoperatively, and 2 weeks and 3 months postoperatively to assess voice outcomes after thyroidectomy. In addition, 16 patients who underwent a nonneck operation were tested as a control group. Maximum phonation time (MPT), mean airflow, R(law), and PTP were determined at two vocal fundamental frequency (F0) levels (30% and 80% of the F0 range).

RESULTS

No systematic differences were detected for MPT, mean airflow, or R(law) as a short-term or intermediate-term outcome of either surgical group. PTP decreased significantly over time for both groups of participants and at both F0 levels. F0 range decreased significantly at the short-term postsurgical assessment and covaried with the PTP results, thereby explaining some of the variability in the PTP data.

CONCLUSIONS

Aerodynamic assessment did not reveal systematic changes in vocal function associated with thyroidectomy, although PTP decreased postoperatively for both surgical groups. This may be attributable in part to a learning effect or to postoperative reductions in F0 range.