The importance of pre- and postoperative laryngeal examination for thyroid surgery

Outcomes of a first point of contact speech language therapy clinic for patients requiring vocal cord check pre and post thyroid/parathyroid surgery

INTRODUCTION

Speech Language Therapy First Point of Contact Clinic (SLT-FPOCC) models can assist assessment of low-risk patient populations referred to ear, nose and throat (ENT) services. To further improve ENT waitlist management and compliance with best-practice care, consideration of other low-risk populations that could be safely managed through this service model is needed. The aims of this paper are to evaluate the clinical and service outcomes of completing vocal cord check (VCC) assessments for patients' pre and post thyroid/parathyroid surgery within an SLT-FPOCC model and examine consumer perceptions.

METHODS & PROCEDURES

The service followed existing SLT-FPOCC procedures, with ENT triaging referrals, then SLT completing pre- and postoperative VCC assessment (interview, perceptual assessment, flexible nasendoscopy), with assessment data later reviewed by ENT to diagnose laryngeal pathology. Clinical and service outcomes were collected prospectively. Patients completed an anonymous post-service satisfaction survey.

RESULTS

Of the first 100 patients referred for preoperative VCCs, SLT assessment identified 42 with dysphonia and 30 reporting dysphagia, while ENT confirmed 9 with significant preoperative anatomical findings. Eighty-three underwent surgery, with 63 (95 nerves at surgical risk) returning for a postoperative VCC. Postoperative VCC identified three temporary neuropraxias (3.2%) and three unilateral vocal fold paresis (3.2%). Patients were highly satisfied with the service. All 163 pre-/postoperative VCCs were completed with no adverse events.

CONCLUSION & IMPLICATIONS

The current data support SLT-FPOCC service expansion to include pre and post thyroid/parathyroid surgery VCC checks, with positive consumer perception. The model supports delivery of best practice management (i.e., pre- and postoperative VCC) for patients receiving surgery for thyroid/parathyroid dysfunction, and associated efficiencies for ENT services.

WHAT THIS PAPER ADDS

What is already known Assessment of laryngeal function via flexible nasoendoscopy is recommended best practice for patients pre and postthyroid/parathyroid surgery, as recurrent laryngeal nerve injury is a low incidence (<10%), yet well-recognised risk of these surgeries. Traditionally, general surgeons refer presurgical patients to ear, nose and throat (ENT) for vocal cord check (VCC) assessment. However, with access to specialist outpatient services under increasing pressure, there is growing support for utilisation of other health professionals, such as speech-language therapists working in first point of contact (FPOCC) models, to assist with the administration of pre- and postsurgical assessments of such low-risk populations. What this study adds This work expands on the emerging body of evidence for speech language therapy (SLT) led FPOCC models within ENT outpatient services, providing clinical and service outcomes to support the safety of a new model designed to administer VCCs for patients pre and post thyroid/parathyroid surgery. Adopting a similar model to a prior published SLT-led FPOCC model, the trained SLT completes the pre- and postsurgical VCC including flexible nasoendoscopy and videostroboscopy, with images and clinical information then presented to ENT for diagnosis and management planning. This study also provides the first data on consumer perceptions of this type of service model. Clinical implications of this study Data on 100 consecutive presurgical patients revealed positive service findings, supporting the safety of this model. Nature and incidence of clinical findings pre and post surgery were consistent with previously published studies using traditional models of care (i.e., ENT completing the flexible nasendoscopy). Consumer perception was positive. This model enables delivery of pre-and postsurgical assessments for patients receiving thyroid/parathyroid surgery, consistent with best practice care, and reduces burden on ENT services. In total 163 ENT appointments were avoided with this model, with positive implications for ENT waitlist management.

Total areola approach for endoscopic thyroidectomy: Six years of experience with the same surgeon

Background

Scarless endoscopic thyroidectomy (ET) is increasingly accepted by the growing amount of surgeons. The target of this study is to assess the efficacy and summarise the experiences of total areola approach for ET (TAAET).

Subjects and Methods

TAAET was performed on 529 patients between January 2016 and October 2021. All operated patients were divided into two groups according to the chronological order. Demographic data, perioperative data and post-operative complications were collected to assess the effectiveness of TAAET.

Results

Five hundred and twenty-eight patients were successfully treated with TAAET, while 1 case was converted to open surgery due to bleeding. The surgical approach consists of lobectomy or total thyroidectomy with or without central lymph node dissection. The post-operative pathology of 433 (81.9%) patients was diagnosed with T1 ~2N0M0. The average number of unilateral lymph node dissection was 7.72 ± 2.44 while the bilateral lymph node was 10.70 ± 3.72. In terms of complications, 38 cases had transient hoarseness, 28 cases had tetany and numbness, 3 cases had post-operative bleeding, 1 case had infection and 33 cases had subcutaneous fluid. There were statistically significant differences between the two groups with respect to transient hoarseness (P < 0.001), tetany and numbness (P = 0.005), intraoperative blood loss (P = 0.003) and operation time for malignant tumour (P < 0.001) because of the accumulation of surgical experience and the maturation of technology.

Conclusions

TAAET which conforms to the anatomical pathway of open thyroidectomy is a safe, effective and feasible technique and is highly suitable for novices.

Platelet-rich plasma loaded nerve guidance conduit as implantable biocompatible materials for recurrent laryngeal nerve regeneration

Vocal cord paralysis caused by recurrent laryngeal nerve (RLN) injury during thyroidectomy results in hoarseness, aspiration, and dyspnea. We evaluated the usefulness of nerve guidance conduits (NGCs) constructed from an asymmetric polycaprolactone (PCL)/Pluronic F127 porous membrane and filled with platelet-rich plasma (PRP) for functional RLN regeneration. We evaluated the proliferation and migration of Schwann cells (SCs) after PRP treatment in vitro. For the in vivo study, rabbits were divided into a non-loaded NGC group and a PRP-loaded NGC group. The left RLNs were resected and interposed with the NGCs. Functional and histological examinations of the vocal cords were performed. SC proliferation and migration increased in a PRP dose-dependent manner, with the PRP increasing the levels of neurotrophic factors, myelin-associated glycoprotein, and ERK. In vivo, the PRP group showed significantly better vocal cord mobility and less vocalis muscle atrophy than the non-loaded NGC group. Histologically, the ingrowth of nerve endings occurred more rapidly in the PRP group, and acetylcholinesterase, neurofilament, and S-100 expression in neural endings were significantly higher in the PRP group. Furthermore, transmission electron microscopy showed that myelinated axons were more tightly packed in the PRP group. This study shows that PRP-loaded NGCs provide a favorable environment for neural regeneration and suggests that this technique has therapeutic potential for promoting RLN recovery.

Predictions for Three-Month Postoperative Vocal Recovery after Thyroid Surgery from Spectrograms with Deep Neural Network

Despite the lack of findings in laryngeal endoscopy, it is common for patients to undergo vocal problems after thyroid surgery. This study aimed to predict the recovery of the patient's voice after 3 months from preoperative and postoperative voice spectrograms. We retrospectively collected voice and the GRBAS score from 114 patients undergoing surgery with thyroid cancer. The data for each patient were taken from three points in time: preoperative, and 2 weeks and 3 months postoperative. Using the pretrained model to predict GRBAS as the backbone, the preoperative and 2-weeks-postoperative voice spectrogram were trained for the EfficientNet architecture deep-learning model with long short-term memory (LSTM) to predict the voice at 3 months postoperation. The correlation analysis of the predicted results for the grade, breathiness, and asthenia scores were 0.741, 0.766, and 0.433, respectively. Based on the scaled prediction results, the area under the receiver operating characteristic curve for the binarized grade, breathiness, and asthenia were 0.894, 0.918, and 0.735, respectively. In the follow-up test results for 12 patients after 6 months, the average of the AUC values for the five scores was 0.822. This study showed the feasibility of predicting vocal recovery after 3 months using the spectrogram. We expect this model could be used to relieve patients' psychological anxiety and encourage them to actively participate in speech rehabilitation.

Selective laryngoscopy before thyroidectomy: a risk assessment

BACKGROUND

Patients presenting for thyroidectomy may have an unrecognized pre-existing vocal cord palsy (VCP). This raises the danger of bilateral VCP if a patient sustains an injury to the RLN on the sole functioning side. Part of the rationale for routine preoperative laryngoscopy is to eliminate such a risk. This paper endeavours to quantify the relevant potential risk.

METHODS

Patients who underwent laryngoscopy prior to thyroid or parathyroid surgery in an endocrine surgical unit over a 5 year period were identified. Literature review revealed four papers in which VCP prevalence in patients without risk factors was reported. Using our data, combined with that of these other authors, the background rate of pre-existing VCP was ascertained, and the subsequent risk of bilateral VCP estimated.

RESULTS

Of our 632 patients who underwent preoperative laryngoscopy, there were four patients (0.63%) who were found to have a unilateral VCP, but all had voice symptoms or previous neck surgery. When patients with these risk factors are excluded, our data combined with the published data provides a pre-existing VCP rate of 0.2%. Calculations estimate that if preoperative laryngoscopy is omitted in patients with no risk factors, the risk of bilateral VCP, due to the nerve on the sole functioning side being injured, would be between 1/50000 and 1/150000, depending on an individual surgeon's level of experience.

CONCLUSION

Selective use of laryngoscopy prior to thyroidectomy would result in an acceptably low statistical risk of bilateral VCP. Routine laryngoscopy for all patients is not necessary.

Cost-effectiveness of fiberoptic laryngoscopy prior to total thyroidectomy for low-risk thyroid cancer patients

BACKGROUND

Flexible fiberoptic laryngoscopy is performed prior to thyroid surgery to evaluate the function of the recurrent laryngeal nerve. We assess the cost-effectiveness of preoperative laryngoscopy prior to total thyroidectomy for a low-risk thyroid cancer patient without dysphonia.

METHODS

A decision tree analysis was performed from a third-party payer perspective. We assessed the cost-effectiveness of fiberoptic laryngoscopy prior to total thyroidectomy for T2N0M0 papillary thyroid carcinoma, such that an ipsilateral vocal fold paralysis alters the surgical plan to hemi-thyroidectomy, when permissible, to avoid the risk of bilateral vocal fold paralysis.

RESULTS

Performing preoperative laryngoscopy to assess vocal fold function has an incremental cost-effectiveness ratio (ICER) of 45 193 USD/QALY compared to no laryngoscopy. At a willingness-to-pay of 100 K/QALY, the intervention is cost-effective if the incidence of vocal fold paralysis is at least 0.57%, or when the permissible rate of hemithyroidectomy in cases of incidental paralysis is at least 41%. Probabilistic sensitivity analysis shows that laryngoscopy is cost-effective in 90.9% of cases.

CONCLUSIONS

Fiberoptic laryngoscopy is a cost-effective prior to total thyroidectomy in asymptomatic, low-risk thyroid cancer patients.

THYROID SURGERY, IONM AND SUGAMMADEX SODIUM RELATIONSHIPS: BENEFITS IN SUGAMMADEX SODIUM USE FOR IONM

Background

It is important to protect recurrent laryngeal nerve (RLN) during thyroid surgery. Thus, intra- operative neuromonitoring (IONM) has got popularity. But, the half life of neuromuscular blocking agents used has a reverse correlation with reliability and effectiveness of IONM. This study aimed to research the effect of Sugammadex Sodium, a specific nemuromuscular blocking agent antagonist, on nerve conduction and IONM.

Materials and methods

Twenty patients who underwent thyroidectomy under IONM followed an enhanced NMB recovery protocol-rocuronium 0.6 mg/kg at anesthesia induction and sugammadex 2 mg/kg at the beginning of operation. To prevent laryngeal nerve injury during the surgical procedures, all patients underwent intraoperative monitoring. At the same time, the measurement of TOF-Watch acceleromyograph of the adductor pollicis muscle response to ulnar nerve stimulation was performed; recovery was defined as a train-of-four (TOF) ratio ≥ 0.9. Age, sex, recurrent laryngeal nerve transmission speeds prior to and after operation, BMI, duration of surgery, the change in nerve transmission after drug administration and complications were analyzed.

Results

The mean age and the mean BMI were 47.6±11.82 years and 28.74±3.20, respectively. The mean operation duration was 52.65±5.51 minutes. There was no difference in either right or left RLN monitoring values before and after surgery. Following the drug injection, the TOF guard measurements on the 1^st, 2^nd, 3^rd and 4^th minutes were 23.5±4.90; 69.5±6.86; 88±4.1 and 135.9±10.62, respectively.

Conclusion

Neuromuscular blocking antagonist use and monitoring nerve transmission speed with TOF-guard can provide a safer resection.

Preoperative Voice Characteristics in Thyroid Patients

INTRODUCTION

Thyroid surgery outcomes have evolved from mortality control strategies to morbidity control measures. Most vocal outcomes research in thyroid surgery are focused on recurrent nerve anatomic and functional preservation. However, there are likely multiple causes of vocal dysfunction in thyroid patients. We prospectively analyzed preoperative patients with thyroid disease to define preoperative vocal characteristics of this population.

OBJECTIVE

Quantify vocal and laryngeal baseline conditions in thyroid surgical patients.

METHODS

Prospective study of preoperative stroboscopy findings and vocal function assessing the correlation between thyroid disease, compressive symptoms, baseline vocal conditions and laryngoscopy results.

RESULTS

Vocal quantitative scores were positive for dysphonia in 36% of patients and the Vocal Handicap Index confirmed either slight or Moderate impairment in most patients. Stroboscopy results were abnormal in 60% of cases with no diagnoses of immobility. Correlation was established for diagnosis of cancer and the absence of symptoms.

CONCLUSIONS

These results point to a multifactorial cause for vocal impairment in thyroid surgery patients. Research on vocal impairment in thyroid surgery should not be centered exclusively on recurrent nerve neuromonitoring and functional preservation, but also on other variables that may contribute to vocal change in thyroid disease and surgery.

[Update of the S2k guidelines : Surgical treatment of benign thyroid diseases]

Thyroid resections represent one of the most common operations with 76,140 interventions in the year 2016 in Germany (source Destatis). These are predominantly benign thyroid gland diseases. Recommendations for the operative treatment of benign thyroid diseases were last published by the CAEK in 2010 as S2k guidelines (Arbeitsgemeinschaft der Wissenschaftlichen Medizinischen Fachgesellschaften e.V. [AWMF] 003/002) against the background of increasingly more radical resection procedures. Hemithyroidectomy and thyroidectomy are routinely performed for benign thyroid disease in practice. The operation-specific risks show a clear increase with the extent of the resection. Therefore, weighing-up of the risk-indications ratio between unilateral lobectomy or thyroidectomy necessitates an independent evaluation of the indications for both sides. This principle in particular has been used to update the guidelines. In addition, the previously published recommendations of the CAEK for correct execution and consequences of intraoperative neuromonitoring were included into the guidelines, which in particular serve the aim to avoid bilateral recurrent laryngeal nerve paralysis. Moreover, the recommendations for the treatment of postoperative complications, such as hypoparathyroidism and postoperative infections were revised. The updated guidelines therefore represent the current state of the science as well as the resulting surgical practice.

Conventional Thyroidectomy in the Treatment of Primary Thyroid Cancer

This article focuses on conventional surgical management of thyroid cancer, reviewing long-standing and well-accepted main principles and practices. It also covers newer controversies and techniques to conventional thyroidectomy, including changes in the indications for thyroidectomy, the intraoperative management of the recurrent and superior laryngeal nerves and parathyroid glands, the extent of thyroidectomy, and the importance of outcomes measurement and quality improvement.

How does neural monitoring help during thyroid sugery for Graves' disease?

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Risk of RLN palsy during thyroidectomy for Graves’ disease is high.

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I-IONM and C-IONM are feasible and useful during thyroidectomy for Graves’ disease.

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Proportion of complete thyroidectomy was significantly higher using IONM technology.

We evaluate the role of intraoperative neuromonitoring (IONM) in thyroidectomy performed for Graves’ disease (GD) with an emphasis on recurrent laryngeal nerve (RLN) management and completeness of resection. The study is a retrospective series comprising 55 thyroidectomy (control group) versus 82 procedures with intermittent IONM (I-IONM) and 72 by means of continuous IONM (C-IONM). In the control group the laryngeal nerves have been identified by visualization solely. In the I-IONM group both vagal nerve (VN) and RLN have been localized and monitored during thyroid resection. C-IONM was achieved with a vagal stimulation probe. I-IONM group had shorter operating times (P = 0.032). RLN morbidity, meaning palsy rate, was 2.7% in the C-IONM group, 3.6% in I-IONM and 5.4% in the control group (P = 0.058). The proportion of complete procedures (total or near total resections) were significantly higher using monitoring technology (P = 0.049). Persistent positive serum TBII values were found in 25 (45%), 25 (30%) and 20 (27%) patients at 12 months in the control, I-IONM and C-IONM groups respectively (P = 0,04). IONM is an effective technology in GD patients.

The incidence of vocal fold motion impairment after primary thyroid and parathyroid surgery for a single high-volume academic surgeon determined by pre- and immediate post-operative fiberoptic laryngoscopy

BACKGROUND

Vocal fold motion impairment (VFMI) is a well-recognized complication of thyroid and parathyroid surgery. Preoperative counseling requires a thorough understanding of the incidence, risk factors, and value of early diagnosis of postoperative VFMI. Our objective is to describe the incidence of and risk factors for VFMI for a single high-volume academic surgeon, and to assess the utility of immediate postoperative fiberoptic laryngoscopy (FOL) in early diagnosis of VFMI.

METHODS

Retrospective cohort study of patients undergoing primary thyroid and parathyroid procedures by a single high-volume surgeon at an academic tertiary care center. All patients underwent preoperative and immediate postoperative FOL. The primary outcome was incidence of VFMI, either temporary (<1 year) or permanent (1 year or more). The unit of analysis was number of recurrent laryngeal nerves (RLN) at risk. Risk factors for VFMI were analyzed using logistic regression, reporting unadjusted and adjusted odds ratios (OR and aOR) and 95% confidence intervals (CI).

RESULTS

The study population comprised 1547 patients undergoing 1580 procedures for a total of 2527 nerves at risk, excluding the 27 nerves found to have motion impairment on preoperative FOL. Sixty-seven new incidents of VFMI were identified on postoperative FOL, with an additional six new incidents detected after voice complaints prompted FOL upon follow-up. Thus, the incidence of postoperative VFMI was 2.9% of RLNs at risk (73 of 2527). The sensitivity and negative predictive value of immediate postoperative FOL were 92% and 99.8% respectively. Permanent VFMI occurred in 9 cases (0.4%), 3 of which were from intentional RLN transection for malignancy. Odds of VFMI were significantly lower after parathyroidectomy (aOR = 0.1, 95%CI = 0.01-0.8 compared with hemithryoidectomy) and higher with central neck dissection (aOR = 2.4, 95CI = 1.0-5.9). Among cases of malignancy, odds of VFMI increased significantly with increasing T-stage (adjusted p_trend<0.001).

CONCLUSION

VFMI is rare and usually temporary after primary thyroid and parathyroid procedures, with increased risk associated with larger primary malignancies and the inclusion of central neck dissection. Immediate postoperative FOL is useful for early detection of VFMI that may allow for clear definition of temporary and permanent immobility rehabilitation especially if there is evidence to support early intervention.

Analyzing cost-effectiveness of neural-monitoring in recurrent laryngeal nerve recovery course in thyroid surgery

PURPOSE

The increasing use of intraoperative neural monitoring (IONM) of the recurrent laryngeal nerve (RLN) during thyroid surgery imposes an evaluation of cost-effectiveness.

METHODS

The analysis estimated the cost versus utility of different alternatives that simulate nerve injury course and the consequences for the following cohorts of patients: (1) no RLN injury, or vocal fold palsy (VCP) recovery within 1 month (2), 2 months (3), 6 months (4), and after 12 months (5). In the model applied, the average simulated cohort consisted of a young female patient, 40 years old, employed, daily voice user, who underwent elective, conventional total thyroidectomy via cervical incision using a standardized intermittent IONM technique, for an operable benign, bilateral, diffuse, multinodular, non-toxic, non-retrosternal goiter.

RESULTS

IONM was cost-ineffective when parameters such as the rates of transient vocal fold palsy (VCP) reached 38.5%. IONM was cost-effective if the rate of VCP was 33.6% at 1 month, 22.9% at 2 months, 9.8% at 6 months, and 3.8% at 12 months, independent of phono-surgery. The described scenario is cost-effective only in a high-volume setting.

CONCLUSIONS

This study used simulation economic modeling to assess clinical and cost-effectiveness utility of IONM implementation. In light of the limitations of a simulation-based study, we conclusively assumed that IONM is cost-effective for permeant RLN injuries.

Evaluation of Vocal Cord Function Before Thyroidectomy: Experience from a Developing Country

Vocal cord palsy (VCP) is a major complication of thyroidectomy. Some patients have preexisting VCP prompting the need for routine or selective preoperative evaluation of the vocal cords. The study aims at ascertaining the prevalence of preoperative VCP and making appropriate recommendations. This is a retrospective study of all adult patients who had thyroidectomy at the University of Nigeria Teaching Hospital. Case notes of patients who had thyroidectomy at the hospital from July 2010 to June 2015 were retrieved. Variables studied included biodata, duration of goiter, preoperative hoarseness, outcome of indirect laryngoscopy (IDL), histology of specimen, duration of follow-up, and incidence of postoperative hoarseness. Descriptive statistical analysis was done using SPSS version 20. Of the 91 patients aged 21-70 years (mean 42.08 years, SD 15.40), females outnumbered males with a M:F ratio of 1:10.4. Five patients had preoperative hoarseness, but only three had VCP. IDL was done for 25 (27.4%) patients out of which 22 (88.0%) had normal studies while the remaining three (all from the five with hoarseness) had VCP. Histology of the specimens showed malignancy in 10 (11%), benign in 55 (60.4%), and no report in 26 (28.6%). Five of the malignant histology patients showed normal findings on IDL, three had VCP and two had no preoperative IDL. There was no case of asymptomatic VCP. Vocal cord evaluation is recommended for patients with voice symptoms and those with malignant goiter.

Functional regeneration of the transected recurrent laryngeal nerve using a collagen scaffold loaded with laminin and laminin-binding BDNF and GDNF

Recurrent laryngeal nerve (RLN) injury remains a challenge due to the lack of effective treatments. In this study, we established a new drug delivery system consisting of a tube of Heal-All Oral Cavity Repair Membrane loaded with laminin and neurotrophic factors and tested its ability to promote functional recovery following RLN injury. We created recombinant fusion proteins consisting of brain-derived neurotrophic factor (BDNF) and glial cell line-derived neurotrophic factor (GDNF) fused to laminin-binding domains (LBDs) in order to prevent neurotrophin diffusion. LBD-BDNF, LBD-GDNF, and laminin were injected into a collagen tube that was fitted to the ends of the transected RLN in rats. Functional recovery was assessed 4, 8, and 12 weeks after injury. Although vocal fold movement was not restored until 12 weeks after injury, animals treated with the collagen tube loaded with laminin, LBD-BDNF and LBD-GDNF showed improved recovery in vocalisation, arytenoid cartilage angles, compound muscle action potentials and regenerated fibre area compared to animals treated by autologous nerve grafting (p < 0.05). These results demonstrate the drug delivery system induced nerve regeneration following RLN transection that was superior to that induced by autologus nerve grafting. It may have potential applications in nerve regeneration of RLN transection injury.

Intraoperative neuromonitoring for thyroid malignancy surgery: technical notes and results from a retrospective series

This study evaluates the role of intraoperative neuromonitoring (IONM) for thyroidectomy performed in cancer patients with emphasis on postoperative recurrent laryngeal nerve paralysis (RLNP). The study is a retrospective series comprising 76 thyroidectomy alone (control group) versus 76 thyroidectomy with IONM. In the control group the laryngeal nerves have been identified by visualization solely. In the IONM group both vagal nerve and RLN have been localized and monitored during thyroid resection. The main surgical outcome was RLN morbidity. All patients undergo pre- and postoperative laryngeal examination. Overall RLN morbidity was 3.9% in the IONM group and 9.2% in the control group (P < 0.05). There have been two cases of permanent RLNP (2.6%) in the control group and one in the IONM group (1.3%), one case of bilateral RLN injury in the control group. The incidences of temporary RLNP in the IONM group have been 2.6 versus 6.5% in the control group. IONM is an effective procedure in thyroid cancer patients.

Is there a case for selective, rather than routine, preoperative laryngoscopy in thyroid surgery?

BACKGROUND

According to some authors, routine preoperative laryngoscopy should be the standard of care in all patients undergoing thyroid surgery. The rationale for this approach is (I) the risk that a patient has a preoperative vocal cord palsy (VCP) without symptoms; (II) the presence of VCP preoperatively is suggestive of invasive malignancy; (III) it is relevant for the use of intraoperative nerve monitoring; and (IV) surgical strategy may be better defined if a paralysed vocal cord is detected preoperatively.

METHODS

This is a review of studies of patients who underwent routine preoperative laryngoscopy to anticipate preoperative VCP and that evaluated related risk factors, including previous surgery, voice function complaints, and a diagnosis of malignancy. The estimated risk of sustaining preoperative VCF in the absence of these factors was determined. The relevant current guidelines from different professional bodies are also addressed.

RESULTS

The level of evidence that supports routine preoperative laryngoscopy is weak. The risk of harboring preoperative VCP in the absence of previous neck or other risk-related surgery, advanced malignancy or voice symptoms is very low (0.5% of cases).

CONCLUSIONS

Selective rather than routine use of preoperative laryngoscopy may be acceptable provided that the risk of undetected paralysis is as low as can be reasonably ascertained from the available literature.

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.

The cost of vocal fold paralysis after thyroidectomy

OBJECTIVES/HYPOTHESIS

To determine the added cost of care and analyze risk factors in patients who suffered vocal fold paralysis (VFP) after thyroid surgery.

STUDY DESIGN

Retrospective cohort study.

METHODS

Seventy-six patients who developed unilateral or bilateral VFP after thyroidectomy from 2005 through 2009, and a control group of 238 patients who underwent the same surgery without developing VFP, were compared on hospital charges, hospital and intensive care unit (ICU) length of stay (LOS), unplanned intubation, tracheotomies, respiratory failure, readmission, death, pathology, body mass index (BMI), gland weight, swallowing studies, and need for indwelling feeding tube. Differences between outcomes for unilateral VFP patients versus bilateral VFP patients were analyzed. Rate of recovery of VFP and need for further surgery after thyroidectomy were described.

RESULTS

Patients who developed VFP after thyroidectomy had significantly greater rates of all the parameters listed above. BMI, gland weight, and pathology (malignant vs. benign) were not significantly different between the two groups. VFP group underwent additional surgeries after thyroidectomy related to the VFP. Thirty-three% of unilateral VFP patients with long-term follow-up recovered fully. Patients with bilateral VFP with long-term follow-up, had recovery of one vocal fold in 50% and both in 23% of cases.

CONCLUSIONS

Patients with unilateral or bilateral VFP after thyroidectomy experience significantly more morbidity and incurred significantly more health care charges after surgery than similar patients who do not have VFP after thyroidectomy. The likelihood of VFP was not related to malignancy, BMI, or thyroid gland weight in this series.

Loss of the nerve monitoring signal during bilateral thyroid surgery

Background

This study aimed to assess current use of recurrent laryngeal nerve monitoring (RLNM) for bilateral thyroid surgery in Germany. It explored the willingness of surgeons to change strategy after loss of signal (LOS) on the first side of resection.

Methods

Surgical departments in Germany equipped with nerve monitors were asked to complete a structured questionnaire, specifying the number of thyroidectomies done in 2010, and the frequencies of RLNM, vagal stimulation, and electromyographic (EMG) recording before and after thyroidectomy. They were also asked about the surgical plan for bilateral goitre after LOS on the first side of resection.

Results

Based on manufacturers' sales data, 1119 (89·1 per cent) of 1256 surgical departments in Germany were equipped with nerve monitors in 2010. A total of 595 departments (53·2 per cent), accounting for approximately 75 per cent of all thyroidectomies in Germany during that year, returned a completed questionnaire. RLNM was used in 91·7–93·5 per cent of thyroidectomies, with the addition of routine vagal stimulation in 49·3 per cent before, and 73·8 per cent after resection. EMG responses to vagal stimulation were recorded in 54·8 per cent before, and 72·5 per cent after resection. Some 93·5 per cent of surgeons changed the resection plan for the other side in bilateral thyroid surgery after LOS had occurred on the first side.

Conclusion

RLNM is now the standard of care during thyroidectomy in Germany. After LOS on the first side of resection in bilateral goitre, more than 90 per cent of respondents declared their willingness to change the resection plan for the contralateral side to avoid the risk of bilateral recurrent laryngeal nerve palsy.

Clinical value of intraoperative neuromonitoring of the recurrent laryngeal nerves in improving outcomes of surgery for well-differentiated thyroid cancer

The recurrent laryngeal nerve (RLN) is particularly prone to injury during thyroidectomy in case of extralaryngeal bifurcation being present in approximately one-third of patients near the inferior thyroid artery or ligament of Berry. Meticulous surgical dissection in this area may be additionally facilitated by the use of intraoperative neuromonitoring (IONM) to assure safe and complete removal of thyroid tissue. The aim of the study was to verify the hypothesis that meticulous surgical technique of tissue dissection in the area of the posterior surface of the thyroid capsule and adjacent RLN may be additionally facilitated by intraoperative neuromonitoring (IONM), and may contribute to increasing the safety and radicalness of total thyroidectomy in patients with well-differentiated thyroid cancer.

MATERIAL AND METHODS

The outcomes of total thyroidectomy with level VI lymph node clearance for well-differentiated thyroid cancer (WDTC; pT1-3, N0-1, Mx) were retrospectively compared between 151 patients undergoing surgery with IONM (01/2005-06/2009) and 151 patients undergoing surgery without IONM (2003-2004). RLN morbidity (calculated for nerves at risk) was assessed by videolaryngoscopy or indirect laryngoscopy (mandatory before and after surgery and at 12-month follow-up). The anatomical course of the extralaryngeal segment of RLNs were analyzed in detail in each operation. Thyroid iodine uptake (131I) was measured during endogenous TSH stimulation test a week before radioiodine therapy.

RESULTS

Among patients operated with vs. without IONM, the early RLN injury rate was 3% vs. 6.7% (p=0.02), including 2% vs. 5% (p=0.04) of temporary nerve lesions, and 1% vs. 1.7% of permanent nerve events (p=0.31), respectively. Extralaryngeal RLN bifurcation was identified in 42 (27.8%) vs. 25 (16.6%) of patients operated with vs. without IONM, respectively (p=0.001). Mean I-131 uptake following total thyroidectomy with vs. without IONM was 0.67 ± 0.39% vs. 1.59 ± 0.69% (p<0.001). 131I uptake lower than 1% was found in 106 (70.2%) vs. 38 (25.2%) patients operated with vs. without IONM, respectively (p<0.001).

CONCLUSIONS

Most patients with WDTC who undergo total thyroidectomy have a small amount of residual thyroid tissue. The use of IONM may improve the outcomes of surgery among these patients by both increasing the completeness of total thyroidectomy and significantly reducing the prevalence of temporary RLN injury. The possible mechanism of this improvement is the aid in dissection at the level of the Berry's ligament offered by IONM which enhances the surgeon's ability to identify a branched RLN, and allows for reduction of traction injury and neuropraxia of the anterior branch of bifid nerves.

The basis of preoperative vocal fold paralysis in a series of patients undergoing thyroid surgery: the preponderance of benign thyroid disease

BACKGROUND

Preoperative vocal fold paralysis (VFP) is thought to be rare in patients with benign thyroid disease (BTD). In contrast with cases of malignancy, in which the recurrent laryngeal nerve (RLN) should be severed, in patients with BTD and VFP the RLN can be preserved without threatening patients' lives. This study investigates the clinical features that enable identification of patients who have VFP associated with BTD.

METHODS

Medical records of 187 consecutive patients who underwent thyroid surgery were retrospectively reviewed. The association between preoperative VFP and pathology (benign or malignant), clinical features, and treatment results of patients with BTD and VFP were analyzed.

RESULTS

Of the 187 patients, 145 patients had BTD and 8 of these cases (5.52%) had preoperative unilateral VFP. The prevalence of BTD with VFP was 4.3% (8/187). The other 42 patients had malignant thyroid disease and 4 of these cases (9.52%) had preoperative unilateral VFP. None of the aforementioned VFP was caused by previous thyroidectomy or surgery to the neck. Although the relative risk of VFP in patients with thyroid malignancy was 1.726 (9.52%/5.52%), there was no significant association between VFP and malignancy. Of the eight patients with BTD, benign fine-needle aspiration cytology or frozen sections, goiter with a diameter larger than 5 cm, cystic changes, and significant radiologic tracheo-esophageal groove compression were the common findings. During thyroidectomy, the RLN was injured but repaired in three patients. Two events occurred in patients who had severe RLN adhesion to the tumor caused by thyroidectomy performed decades ago. Two of the five patients without nerve injury recovered vocal fold function. The overall VFP recovery rate for patients with BTD and VFP was 25% (2/8).

CONCLUSIONS

Preoperative unilateral VFP is not uncommon in thyroid surgery. Obtaining information on laryngeal function is of extreme importance when planning surgery, especially contralateral surgery. Goiter with preoperative VFP is not necessarily an indicator of malignancy. Benign perioperative cytopathologic findings with typical radiographic compression strongly suggest that VFP is caused by BTD. If, during thyroidectomy, the RLN is carefully preserved, recovery of vocal fold function may still be possible.

Implementation of systematic neuromonitoring training for thyroid surgery

Neural monitoring is increasingly applied to thyroid surgery and yet few surgeons have received formal training in intraoperative neuromonitoring (IONM). Standardized application of neural monitoring is an expected outcome of formal training programs in IONM. This study was designed to document a systematic training course that focuses on standardized state-of-art IONM knowledge. Seventeen 1-day courses were organized by the Department of Surgical Sciences, University of Insubria Medical School (Varese-Como, Italy), between 2009-2010. The course included didactic and practical training sessions. Some specific steps and checklist identified for courses included: knowledge of IONM technology and troubleshooting algorithms; IONM anesthetic perspectives, standards of IONM equipment set up and technique. A total of 75 trainees completed a questionnaire after completion of the respective courses. Questions probed demographic data, operative IONM experience and evaluation of course content. Data gathered showed that 97% of participants had no prior experience with the standardized approach of IONM technique (i.e. stimulation of the vagal nerve). The most useful parts of the course were judged to be (a) algorithms for perioperative IONM problem solving (30%), (b) live surgery with hands-on training (25%), (c) standardization of IONM technique (25%), and (d) IONM equipment set-up (20%). Poor reimbursement for hospital thyroid procedures is the main reason of limitation of IONM technology. The course offered participants novel knowledge and training and gave participants a systematic and standard approach to IONM technique.