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.

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.

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.

Routine Preoperative Laryngoscopy for Thyroid Surgery Is Not Necessary Without Risk Factors.

Background: Routine preoperative vocal cord (VC) assessment with laryngoscopy in patients undergoing thyroidectomy allows clear documentation of baseline VC function, aids in surgical planning in patients with palsies, and facilitates interpretation of intraoperative neuromonitoring (IONM) findings. We aimed to determine the incidence of preoperative vocal cord palsy (VCP); to evaluate the associated risk factors for preoperative VCP; and to calculate the cost-savings potential of implementing a selective approach. Methods: Patients with a pre-thyroidectomy VC assessment by fiberoptic laryngoscopy were retrospectively recruited from the Monash University Endocrine Surgery Unit database from 2000 to 2018. Cases with preoperative VCP were reviewed for potential contributing factors and compared with a non-palsy cohort. Results: Of the 5987 patients who had preoperative laryngoscopy, VCP was documented in 41 (0.68%) patients. Four clinical parameters were found to be potential indicators of VCP, including: age (p < 0.001), nodule ≥3.5 cm recorded on ultrasound imaging (p = 0.01), presence of voice symptoms (p < 0.001), and previous neck surgery (p < 0.001). Malignant cytology (p = 0.5) and exposure to head and neck irradiation were not different between the groups. Utilizing these risk factors, 2354 (39%) patients had at least one feature that may raise suspicion for preoperative VCP. By performing preoperative laryngoscopy only on this subset of patients, the potential cost savings exceeds 400 Australian Dollars per patient. Conclusions: Using this large dataset, we have established that a VCP is rare in the absence of a large nodule, hoarseness, or previous neck surgery. Therefore, in the era of IONM, we support a selective approach to preoperative laryngoscopy by using the aforementioned criteria.

IONM and minimally invasive videoassisted thyroidectomy.

BACKGROUND: We know that benefits of MIVAT are related to a better cosmetic result and lower post-operative pain in comparison to CT. The incidence of nerve cold palsy is related to a correct identification of the recurrent laringeal nerve (RLN) as standard procedure in thyroid surgery. From September 2014 we have introduced the use of intraoperative neural monitoring(I-IONM) in all thyroidectomies in the Unit of General Surgery of University Hospital of Parma, including in MIVAT. PATIENTS AND METHODS: We have considered all patients treated from September 2014 to September 2017 for thyroid diseases using MIVAT and IONM. Intermittent neuromonitoring with NIM-3.0 equipment (Medtronic, Jacksonville, FL, USA) was used during all operations. We have recorded all data about age, sex, diagnosis, surgical time, i-IONM signal, postoperative pain, postoperative hypocalcemia after 24 hours, haematoma and vocal cord palsy. The mean hospital stay was collected from surgical procedure to hospital discharge. We have considered vocal dysfunctions that persist six months after surgery as permanent. RESULTS: From September 2014 to September 2017 we treated consecutively with both MIVAT and i-IONM 100 patients. Considering the extent of surgery, 26 pts underwent to hemithyroidectomy and 74 pts to total thyroidectomy. The mean surgical time was 61.8 minutes. In 7 cases the patients were affected by preoperative clinical dysphonia. Using I-IONM during thyroidectomy, we recorded in 5 cases (5%) a loss of signal; in two cases (2%) we experienced a temporary postoperative vocal cord palsy. DISCUSSION: In our experience the use of IONM has improved the safety during thyroidectomy because precision that can be achieved by endoscopic procedures is further improved by complementary use of IONM. The costs associated to a potential reduction of medical litigation have not been investigated.

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.

A Cost-Utility Analysis of Recurrent Laryngeal Nerve Monitoring in the Setting of Total Thyroidectomy.

Importance: Intraoperative nerve monitoring (IONM) of the recurrent laryngeal nerve (RLN) is used as a tool to decrease the rate of nerve injury, although study findings are divergent on IONM efficacy. The cost-effectiveness of this approach to total thyroidectomy has not been well studied. Objective: To determine whether IONM is a cost-effective intervention in the setting of total thyroidectomy. Design and Setting: This study creates a decision-tree model of total thyroidectomy to analyze, from a societal perspective, the cost-effectiveness of universal IONM (ie, use in every case) vs selective IONM (ie, high-risk cases including reoperative cases, substernal or toxic goiters, and cases with known cancer) vs no IONM (visual identification only). Parameters for the model were derived from review of the literature, and deterministic and probabilistic analyses were performed to test the model's robustness. All analyses were performed from the model; there were no human participants. Interventions: Modeled total thyroidectomy with and without IONM of the RLN. Main Outcomes and Measures: Cost-effectiveness of universal IONM vs selective IONM vs visual identification only of the RLN. Results: Visual identification of the RLN led to a cost savings of $179.40 and $683.20 per patient, and an improvement of 0.001 and 0.004 quality-adjusted life-years, over selective IONM and universal IONM, respectively. Visual identification was the most cost-effective approach, despite variations in costs and utilities in both deterministic and probabilistic sensitivity analyses. In a 1-way sensitivity analysis, decreasing the probability of RLN injury with IONM made selective IONM more cost-effective. When the rate of RLN injury for visual identification was kept constant (at 3.86%), selective IONM became the most cost-effective approach when its RLN injury rate dropped below 1.9%. As the rate of RLN injury with IONM dropped below 50.4% of the visual identification RLN injury rate, selective IONM became the most cost-effective approach. Conclusions and Relevance: Visual identification of the RLN is more cost-effective than any use of IONM. If a clinician can, with use of IONM, decrease the rate of RLN injury by 50.4% or more compared with visual identification, selective use of IONM in high-risk cases is most cost-effective.

Analysis of Variations in the Use of Intraoperative Nerve Monitoring in Thyroid Surgery.

IMPORTANCE: Intraoperative nerve monitoring (IONM) is increasingly performed during thyroid surgery. OBJECTIVE: To examine the use of IONM and its association with patient demographic characteristics and surgeon volume. DESIGN, SETTING, AND PARTICIPANTS: A cross-sectional analysis used the State Inpatient Databases from January 1, 2010, to December 31, 2011, to assess patient demographic characteristics and surgeon volume. Available 30-day readmission data for all adult patients (aged ≥18 years) who underwent thyroidectomy in Florida, New York, and Washington were included. Follow-up was completed on December 31, 2011, and data were analyzed from March 11, 2015, to February 17, 2016. MAIN OUTCOMES AND MEASURES: Use of IONM and incidence of postoperative vocal cord paralysis. RESULTS: A total of 17 268 patients undergoing thyroidectomy were included (20.3% men; 79.7% women; mean [SD] age, 53.0 [15.1] years), of whom 1433 patients (8.3%) had IONM. Patients who were significantly less likely to undergo IONM included black patients (185 [7.9%]; adjusted odds ratio [AOR], 0.79; 95% CI, 0.65-0.97) and those with Medicare (382 [8.4%]; AOR, 0.81; 95% CI, 0.69-0.94) or Medicaid (125 [5.5%]; AOR, 0.59; 95% CI, 0.48, 0.74) health coverage. Black patients had a higher prevalence of vocal cord paralysis compared with white patients (37 [1.6%] vs 138 [1.3%]; AOR, 1.64; 95% CI, 1.11-2.43) in a multivariate model that also controlled for IONM use. Low-volume surgeons were more likely to use IONM (1199 [9.2%] vs 234 [5.5%]; AOR, 1.76; 95% CI, 1.48-2.09). However, patients treated by low-volume surgeons had a higher risk for vocal cord paralysis compared with those treated by high-volume surgeons (187 [1.4%] vs 26 [0.6%]; AOR, 2.47; 95% CI, 1.61-3.80). The risk for vocal cord paralysis was not associated with the performance of IONM (AOR, 0.74; 95% CI, 0.48-1.16) or the type of thyroidectomy (AOR, 1.04; 95% CI, 0.75-1.44). CONCLUSIONS AND RELEVANCE: Disparities in the use of IONM are based on demographic factors of the patients and surgeon volume. Intraoperative nerve monitoring appears to be used less in black patients or those with Medicare health coverage and is not associated with the risk for vocal cord paralysis.

Using Transcutaneous Laryngeal Ultrasonography (TLUSG) to Assess Post-thyroidectomy Patients' Vocal Cords: Which Maneuver Best Optimizes Visualization and Assessment Accuracy?

To assess vocal cord (VC) movement with transcutaneous laryngeal ultrasound (TLUSG), three maneuvers, namely passive (quiet respiration), active (phonation), and Valsalva maneuvers have been described. It remains unclear which maneuver or using more maneuvers provides better visualization and assessment accuracy. We prospectively evaluated 342 post-thyroidectomy patients from two centers. They underwent TLUSG with direct laryngoscopic (DL) validation afterwards. During TLUSG, patients were instructed to perform all three maneuvers (passive, active, and Valsalva). VC visualization rate and accuracy between three maneuvers were compared. Visualization rate tended to be higher in Valsalva maneuver than that in other two maneuvers (92.1% vs. passive: 91.5%; active: 89.8%). While 19 patients had post-operative VC palsy, passive maneuver had lower test specificity than active (94.3 vs. 97.6%, p = 0.01) and Valsalva maneuvers (94.3 vs. 97.4%, p = 0.02). In assessable VCs, passive maneuver has a higher ability to differentiate between mobile VCs and VC palsy (Area under ROC curve--passive: 0.942, active: 0.863, Valsalva: 0.893). TLUSG with more maneuvers did not improve sensitivity or specificity. On applying TLUSG as a screening tool (i.e., only selected patient with "unassessable" VCs or VCP on TLUSG for DL), Valsalva maneuver (85.96%) saved more patients from DL than passive (81.87%) or active (84.81%) maneuver. Passive maneuver has a higher ability to differentiate VC palsy from normal. Using TLUSG as a screening tool, Valsalva was the preferred maneuver as it was more specific, had high visualization rate, and saved more patients from DL.

Assessment of recurrent laryngeal nerve function during thyroid surgery.

INTRODUCTION: There is disparity in the reported incidence of temporary and permanent recurrent laryngeal nerve (RLN) palsy following thyroidectomy. Much of the disparity is due to the method of assessing vocal cord function. We sought to identify the incidence and natural history of temporary and permanent vocal cord palsy following thyroid surgery. The authors wanted to establish whether intraoperative nerve monitoring and stimulation aids in prognosis when managing vocal cord palsy. METHODS: Prospective data on consecutive thyroid operations were collected. Intraoperative nerve monitoring and stimulation, using an endotracheal tube mounted device, was performed in all cases. Endoscopic examination of the larynx was performed on the first postoperative day and at three weeks. RESULTS: Data on 102 patients and 123 nerves were collated. Temporary and permanent RLN palsy rates were 6.1% and 1.7%. Most RLN palsies were identified on the first postoperative day with all recognised at the three-week review. No preoperative clinical risk factors were identified. Although dysphonia at the three-week follow-up visit was the only significant predictor of vocal cord palsy, only two-thirds of patients with cord palsies were dysphonic. Intraoperative nerve monitoring and stimulation did not predict outcome in terms of vocal cord function. CONCLUSIONS: Temporary nerve palsy rates were consistent with other series where direct laryngoscopy is used to assess laryngeal function. Direct laryngoscopy is the only reliable measure of cord function, with intraoperative monitoring being neither a reliable predictor of cord function nor a predictor of eventual laryngeal function. The fact that all temporary palsies recovered within four months has implications for staged procedures.

[Surgery for benign goiter in Germany: fewer operations, changed resectional strategy, fewer complications]. / Strumachirurgie in Deutschland: Weniger Operationen, geänderte Resektionsstrategien, weniger Komplikationen.

BACKGROUND: The increase of certain operations in the wake of the introduction of the German Diagnosis-Related Groups (G-DRG) system rekindled debate on the risk-benefit profile of what is widely being perceived as a too high number of thyroidectomies for benign goiter in Germany. MATERIAL AND METHODS: The numbers of thyroidectomy for benign goiter from 2005-2011 were obtained from the Federal Bureau of Statistics ("Statistisches Bundesamt"). For the purpose of the study, the following operation and procedure key (OPS) codes were selected: hemithyroidectomy (OPS code 5-061); partial thyroid resection (OPS code 5-062); total thyroidectomy (OPS code 5-063); and thyroid surgeries via sternotomy (OPS code 5-064). The rates of permanent hypoparathyroidism and vocal cord palsy were calculated based on two prospective multicenter evaluation studies conducted in 1998-2001 (PETS 1) and 2010-2013 (PETS 2) in Germany. RESULTS: Between 2005 and 2011, the number of thyroidectomies for benign thyroid goiter decreased by 8 %, and the age-standardized surgery rate decreased by 6 % in men (2005: 599 per 1 million; 2011: 565 per 1 million) and 11 % in women (2005: 1641 per 1 million; 2011: 1463 per 1 million). At the same time, the rates of partial and subtotal thyroidectomy decreased by 59 % in men and 64 % in women, whereas the rates of hemithyroidectomy and total thyroidectomy increased by 65 % (113 %) in men and 42 % (97 %) in women. Despite a greater proportion of thyroidectomies over time, the approximated rates for postoperative hypoparathyroidism were reduced from 2.98 to 0.83 % and for postoperative vocal cord palsy from 1.06 to 0.86 %. Irrespective of that decline, either complication was more frequent after total than after subtotal thyroidectomy. CONCLUSION: The total number of thyroid surgeries due to benign goiter has decreased substantially in Germany from 2005 through 2011. Despite changes in the resectional strategy with an increase in the total number thyroidectomies and a decrease of subtotal resections, the rates for postoperative hypoparathyroidism and vocal cord palsy have decreased. The complication rates for total thyroidectomy, however, are still higher compared to subtotal resection. An individualized risk-oriented surgical approach is warranted.

Recurrent laryngeal nerve and voice preservation: routine identification and appropriate assessment - two important steps in thyroid surgery.

INTRODUCTION: The aims of this study were to assess and compare vocal cord functions before and after thyroid surgery after intra-operative identification of recurrent laryngeal nerve. PATIENTS AND METHODS: Recurrent laryngeal nerve (RLN) is seen intra-operatively in all cases undergoing thyroid surgeries. Vocal cord functions including any voice change were evaluated by indirect laryngoscopy (I/L) and direct laryngoscopy (D/L) before and after surgery. RESULTS: Prospective study on 100 patients over 18 months with a total of 146 nerves at risk (NAR). Majority were women (n = 86) with mean age of 37.48 years (range, 13-60 years). RLN was seen in all patients and 19 patients complained of some change in quality of their voice after surgery. Evaluation by I/L and D/L at 6 weeks showed recurrent laryngeal nerve palsy (RLNP) in nine (47.36%) and five (26%) of these 19 patients respectively. Analysed according to total NAR, the incidence of voice change and temporary RLN palsy (I/L and D/L) at 6 weeks was still less at 13.01%, 6.16% and 3.42%, respectively. Voice change improved in all cases at 3 months with no RLNP palsy by I/L or D/L. All these 19 patients had undergone difficult or extensive surgery for malignancy, large gland, extratyhroidal spread or fibrosis. CONCLUSIONS: Despite identification and preservation of RLN, patients can develop postoperative voice change and RLNP although all voice change cannot be attributed to damaged RLN. Proper assessment of vocal cord functions by I/L and D/L laryngoscopy is required to rule out injuries to these nerves. Risk of damage is higher in patients undergoing more difficult surgery.

[Intraoperative neuromonitoring of thyroid gland operations : Surgical standards and aspects of expert assessment]. / Intraoperatives Neuromonitoring bei Schilddrüsenoperationen : Chirurgische Standards und gutachterliche Aspekte.

Intraoperative neuromonitoring (IONM) was introduced into thyroid surgery approximately 10 years ago for better identification of recurrent laryngeal nerve palsy. Since then several studies have been performed for evaluation of this new technology. IONM is superior to visual nerve identification alone for prediction of postoperative local cord function. Therefore, in bilateral procedures IONM enables intraoperative decision-making concerning resection of the second side. To avoid misinterpretation of the results of IONM a standardized approach including preoperative and postoperative laryngoscopy and preresection and postresection vagus stimulation is recommended. Trouble-shooting requires systematic checking of the device including control of electrode position (needle or tube electrodes). For expert assessment purposes documentation of the standardized application of IONM is of utmost importance.

Recurrent laryngeal nerve identification and assessment during thyroid surgery: laryngeal palpation.

Electrical identification and monitoring of the recurrent laryngeal nerve (RLN) has been proposed as an adjunct to standard visual identification of the nerve during thyroid and parathyroid surgery. This study was undertaken to assess laryngeal palpation as an intraoperative technique for identifying and assessing the RLN during surgery and to investigate the relation between laryngeal palpation and associated laryngeal electromyographic (EMG) activity. The postcricoid region of the larynx during surgery was palpated through the posterior hypopharyngeal wall to sense posterior cricoarytenoid muscle contraction in response to ipsilateral RLN stimulation (i.e., the "laryngeal twitch response.") Laryngeal palpation was performed in a series of 449 consecutive thyroid and parathyroid surgeries with 586 RLNs at risk. All patients underwent preoperative and postoperative laryngoscopy to assess vocal cord mobility. In a subset of patients, laryngeal palpation and simultaneous laryngeal EMG recordings were compared during intraoperative RLN stimulation. In this series, there was no permanent RLN paralysis. There was one case of temporary RLN paralysis secondary to neural stretch that resolved 6 weeks postoperatively (temporary paralysis rate: 0.2% of patients, 0.2% of nerves at risk). Intraoperative laryngeal palpation of the laryngeal twitch response reliably correlated with normal postoperative vocal cord function. Loss of the laryngeal twitch response occurred in the single case of temporary paralysis in the setting of an anatomically intact nerve. Laryngeal palpation correlated well with simultaneous laryngeal EMG activity. There were no palpation-induced laryngeal injuries or laryngeal edema. There were also no RLN injuries due to repetitive neural stimulation. Intraoperative laryngeal palpation during RLN stimulation is a safe, reliable method for neural monitoring that can assist in RLN identification and assessment during thyroid and parathyroid surgery. Most importantly, it provides important prognostic information regarding ipsilateral vocal cord function at the completion of the initial side of the thyroid or parathyroid surgery. Intraoperative laryngeal palpation allows the surgeon to stage contralateral surgery if RLN damage is diagnosed, thereby avoiding the potential for bilateral vocal cord paralysis. We believe that laryngeal palpation is useful as an adjunct to formal EMG monitoring during thyroid and parathyroid surgery.