Ahmed Deniwar

Electrophysiological neural monitoring of the laryngeal nerves in thyroid surgery: review of the current literature.

Recurrent laryngeal nerve (RLN) injury is one of the most common complications of thyroid surgery. RLN injury can cause vocal cord paralysis, affecting the patients voice and the quality of life. Injury of the external branch of the superior laryngeal nerve (EBSLN) can cause cricothyroid muscle denervation affecting high vocal tones. Thus, securing the laryngeal nerves in these surgeries is of utmost importance. Visual identification of the nerves has long been the standard method for this precaution. Intraoperative neuromonitoring (IONM) has been introduced as a novel technology to improve the protection of the laryngeal nerves and reduce the rate of RLN injury. The aim of this article is to provide a brief description of the technique and review the literature to illustrate the value of IONM. IONM can provide early identification of anatomical variations and unusual nerve routes, which carry a higher risk of injury if not detected. IONM helps in prognosticating postoperative nerve function. Moreover, by detecting nerve injury intraoperatively, it aids in staging bilateral surgeries to avoid bilateral vocal cord paralysis and tracheostomy. The article will discuss the value of continuous IONM (C-IOMN) that may prevent nerve injury by detecting EMG waveform changes indicating impending nerve injury. Herein, we are also discussing anatomy of laryngeal nerves and aspects of its injury.

Examining the Bethesda criteria risk stratification of thyroid nodules

BACKGROUND The Bethesda criteria are proposed for appropriate stratification of malignancy risk in thyroid nodules, but controversy exists regarding their accuracy and reliability in decision making. Additionally, previous studies have suggested higher rates of both malignancy and false negative fine needle aspiration biopsy (FNA) associated with increasing nodule size. This study aims to determine the accuracy of ultrasound (US)-guided FNA using the current Bethesda criteria in surgical practice. We also aimed to investigate the relationship between nodule size and malignancy. METHODS A retrospective analysis of US-guided FNAs by a single surgeon during a 4.5 year period. FNA results using Bethesda criteria were compared to final surgical pathology. RESULTS 611 patients with thyroid nodules underwent US-guided FNA. FNA results in 375 subsequently excised thyroid nodules were recorded according to the Bethesda criteria: 192 (51%) benign, 65 (17%) atypia of unknown significance/follicular lesion of undetermined significance (AUS/FLUS), 42 (11%), suspicious for follicular neoplasm (SFN), 17 (5%) suspicious for malignancy (SM), 28 (8%) malignancy, and 31 (8%) non-diagnostic. Malignancy was confirmed by surgical pathology in 15%, 34%, 50%, 88%, 100%, and 39% of the above groups respectively. Sensitivity, specificity, and false-negative rate were 61%, 99%, and 15% respectively. No correlation existed between the size of nodules with indeterminate FNA results and malignancy rate (p=0.89), or size of nodules with non-diagnostic FNA and malignancy rate (p=0.50). CONCLUSION The current Bethesda risk stratification system underestimated malignancy rates in benign, indeterminate and non-diagnostic cytopathologic categories in our experience. There was no positive linear correlation between nodule size and malignancy rate in these cytopathologic categories.

Assessment of Vocal Fold Function Using Transcutaneous Laryngeal Ultrasonography and Flexible Laryngoscopy.

IMPORTANCE Evaluation of preoperative and postoperative vocal fold function is important in patients undergoing thyroid or parathyroid surgical procedures. Transcutaneous laryngeal ultrasonography (TLUSG) has been proposed as a promising noninvasive technique and alternative to flexible fiberoptic laryngoscopy. OBJECTIVE To determine whether TLUSG can be an alternative to flexible laryngoscopy in evaluating vocal fold function. DESIGN, SETTING, AND PARTICIPANTS A prospective study was performed from March 1, 2013, to July 31, 2014. Patients who were scheduled to undergo thyroid or parathyroid surgery by a single surgeon at a North American, university-based tertiary care center and who agreed to undergo preoperative and postoperative TLUSG and flexible fiberoptic laryngoscopy were enrolled. Patients were divided into 2 groups: nonoverweight (body mass index [calculated as weight in kilograms divided by height in meters squared] <25) and overweight or obese (body mass index ≥ 25). Follow-up was completed on February 28, 2015, and data were analyzed from March 1, 2013, to February 28, 2015. INTERVENTIONS Preoperative and postoperative TLUSG and flexible fiber optic laryngoscopic assessments of vocal fold function. MAIN OUTCOMES AND MEASURES The findings of TLUSG and flexible fiber optic laryngoscopy were compared for all patients and each body mass index group to assess the accuracy of TLUSG in assessing vocal fold function. RESULTS A total of 250 patients (500 vocal folds) underwent evaluation, of whom 208 (83.2%) were women and with a mean (SD) age of 52.7 (14.3) years. On flexible fiberoptic laryngoscopy findings, 13 patients had preoperative vocal fold paralysis (VFP), and 14 postoperative new incidents of VFP were identified. Only 7 (53.9%) of the preoperative cases of VFP and 15 (55.6%) of the postoperative cases of VFP were identified by TLUSG. The sensitivity, specificity, and accuracy of preoperative TLUSG were 53.8%, 50.5%, and 50.6%, respectively; for postoperative TLUSG, 55.6%, 38.7%, and 39.6%, respectively. In the nonoverweight group, the preoperative TLUSG sensitivity, specificity, and accuracy were 100%, 70.0%, and 70.5%, respectively; in the overweight-obese group, 45.4%, 43.4%, and 43.5%, respectively (odds ratio, 3.16; 95% CI, 2.06-4.84; P < .001). Postoperative visualization of the vocal folds was more challenging, with a sensitivity, specificity, and accuracy of 83.3%, 55.6%, and 56.8%, respectively, in the nonoverweight group, and 47.6%, 32.6%, and 33.4%, respectively, in the overweight-obese group (odds ratio, 2.62; 95% CI, 1.75-3.94; P < .001). CONCLUSIONS AND RELEVANCE When evaluation of vocal fold function is indicated in patients undergoing thyroid and parathyroid surgery, TLUSG should not be considered as an alternative to the current practice of flexible fiberoptic laryngoscopy. Adequate ultrasonographic visualization of the vocal folds and arytenoids is challenging, especially in overweight and obese patients and in the postoperative setting.

Robotic Thyroidectomy Versus Nonrobotic Approaches A Meta-Analysis Examining Surgical Outcomes

Background. Robotic surgery has been recently used as a novel tool for remote access thyroid surgery. We performed a meta-analysis of the current literature to examine the safety and oncological efficacy of robotic surgery compared to endoscopic and conventional approaches for different thyroid procedures. Methods. A systematic search of the online data bases was done using the following (MeSH) terms “robotic surgery,” “robotic thyroidectomy,” “robot-assisted thyroidectomy,” and “robot-assisted thyroid surgery.” Outcomes measured included total operative time, length of hospital stay, postoperative thyroglobulin levels, and postoperative complications. Statistical differences were analyzed between groups through the standard means and/or relative risk by using STATA analytical software. Results. In this study, 144 articles were identified; of which 18 of them met our inclusion criteria, totaling 4878 patients. Robotic approach was associated with longer total operative time (mean difference of 43.5 minutes) when compared to the conventional cervical approach (95% CI = 20.9-66.2; P < .001). Robotic approach was also found to have a similar risk of total postoperative complications when compared to the conventional and endoscopic approaches. Conclusion. Robotic thyroid surgery is as safe, feasible and provides similar periperative complications and oncological outcomes when compared to both, conventional cervical and endoscopic approaches. However, robotic thyroid surgery is associated with longer operative time when compared to the conventional open approach.

Association of Malignancy Prevalence With Test Properties and Performance of the Gene Expression Classifier in Indeterminate Thyroid Nodules

Importance It is crucial for clinicians to know the malignancy prevalence within each indeterminate cytologic category to estimate the performance of the gene expression classifier (GEC). Objective To examine the variability in the performance of the GEC. Design, Setting, and Participants This retrospective cohort study of patients with Bethesda category III and IV thyroid nodules used single-institution data from January 1, 2013, through February 29, 2016. Expected negative predictive value (NPV) was calculated by adopting published sensitivity and specificity. Observed NPV was calculated based on the true-negative rate. Outcomes were compared with pooled data from 11 studies published January 1, 2010, to January 31, 2016. Results A total of 145 patients with 154 thyroid nodules were included in the study (mean [SD] age, 56.0 [16.2] years; 106 females [73.1%]). Malignancy prevalence was 45%. On the basis of this prevalence, the expected NPV is 85% and the observed NPV is 69%. If the prevalence is assumed to be 25%, the expected NPV would be 94%, whereas the observed NPV would be 85%. Pooled data analysis of 11 studies comprising 1303 participants revealed a malignancy prevalence of 31% (95% CI, 29%-34%) and a pooled NPV of 92% (95% CI, 87%-96%). Conclusions and Relevance In this study, variability in the performance of the GEC was not solely a function of malignancy prevalence and may have been attributable to intrinsic variability of the test sensitivity and specificity. The utility of the GEC in practice is elusive because of this variability. A better definition of the GEC’s intrinsic properties is needed.

Electrophysiologic identification and monitoring of the external branch of superior laryngeal nerve during thyroidectomy

The aim of the study is to examine the correlation between weight, gender, and race with external branch of superior laryngeal nerve (EBSLN) visualization. Furthermore, we compared normative EBSLN neural‐monitoring values to those of the recurrent laryngeal nerve (RLN).

A Prospective Study Comparing the Efficacy and Surgical Outcomes of Harmonic Focus Scalpel Versus LigaSure Small Jaw in Thyroid and Parathyroid Surgery

Background. The use of sealing devices has been established in thyroid surgeries. Recently, LigaSure Small Jaw (LS), a new device that utilizes bipolar energy, was approved by the Food and Drug Administration for use in different head and neck procedures. The purpose of this study is to assess the efficiency and safety of LS use in thyroid surgery compared to Harmonic Focus Scalpel (HS), a well-established device. Methods. A prospective study was conducted to compare the efficacy of LS versus the HS. We evaluated 301 patients who underwent surgery at a North American academic institution. Patients were allocated into two groups according to LS or HS use. All patients underwent vocal cord assessment using direct laryngoscopy preoperatively and postoperatively. Analyses were performed to examine the difference in perioperative outcomes resulting from the utilization of either device. Results. No difference was seen in operative time between both groups (124.20 ± 68.44 minutes in HS vs 125.20 ± 72.13 minutes in LS, P = .99). Overall complications were similar between both groups (22.86% in HS vs 13.84% in LS, P = .05). However, LS use was also associated with a lower incidence of postoperative transient hypocalcemia as compared to the HS (P = .025). No significant difference was found between both groups regarding the incidence of recurrent laryngeal nerve injury (P = .52). Conclusion. The use of the LS is safe, feasible, and is associated with comparable outcomes to HS. Both intraoperative and postoperative variables were similar between both devices. Future larger studies are warranted to further investigate the effect on postoperative transient hypocalcemia.

Can Suspicious Ultrasound Features Predict BRAFV600E Status in Papillary Thyroid Cancer

Background: Papillary thyroid carcinoma (PTC) can be predicted from certain suspicious ultrasound (US) features of thyroid nodules. The aim of this study was to examine if these suspicious features can predict the more aggressive PTC associated with B-type Raf kinase (BRAFV600E) mutation. Methods: This was a retrospective review of prospectively collected data on patients with PTC and known BRAFV600E status. All patients underwent preoperative US by the same surgeon who performed all the operations. We divided patients into BRAFV600E positive and negative groups. All ultrasonographic data were collected including nodule size, echogenicity, solid or cystic nature, presence of calcifications, irregular margins, and internal vascularity. Results: Of 141 patients with PTC, BRAFV600E mutation was detected in 48 (34.0%) patients. There was no significant difference in nodule size (2.06 cm ± 1.37 vs. 2.15 cm ±1.55, p = 0.75) between BRAFV600E positive and negative groups. BRAFV600E positivity was associated with higher rates of hypoechogenicity (57.5% vs. 36.6, p = 0.02), calcifications (48.9 vs. 19.4%, p < 0.01), and irregular margins (21.3 vs. 6.5%, p < 0.01). There was no significant difference in the noncystic nature or internal vascularity between BRAFV600E positive and negative groups. The presence of all suspicious US features is associated with a positive predictive value of 100.0%. In the absence of all suspicious features, the negative predictive value was 84.2%. When suspicious lymph nodes (LNs) detected by preoperative US were compared, there was no significant difference between BRAFV600E positive and negative groups (30.6 vs. 21.7%, p = 0.35). Conclusion: The presence of multiple suspicious US findings of thyroid nodules can predict the BRAFV600E mutation status of papillary thyroid cancer nodules. The highest accuracy overall (93.2%) was achieved by combining calcification, irregular margins, and hypoechogenicity with extrathyroidal extension and LN metastasis. Future multi-institutional studies are warranted to help surgeons with risk stratification and operative planning for patients with papillary thyroid cancer.

Surgical Approaches to the Recurrent Laryngeal Nerve

During thyroid and parathyroid surgery, avoiding injury to the recurrent laryngeal nerve (RLN) is critical. Several general principles should be adhered to when performing these surgeries in order to protect the nerve. Visual identification and dissection of the RLN is now the standard technique for its preservation during thyroid surgery. Based on the pathology and indication for surgery, the optimal approach to the RLN, lateral, superior or inferior, should be utilized.

Lithium-Associated Hyperparathyroidism: A Pooled Analysis.

Background: Lithium treatment has been associated with hyperparathyroidism (HPT). However, there are conflicting data regarding the rate of single- (SGD) versus multiple-gland disease (MGD) as well as the optimum surgical approach in these cases. Methods: Published data were identified through systematic electronic literature searches. Studies that fulfilled the preset inclusion criteria were analyzed (n = 12). Results: These studies documented 210 lithium-associated HPT (LAH) cases. Of these, 103 (49%) were due to SGD and 107 (51%) due to MGD. The unadjusted odds ratio of having multiple LAH compared to sporadic HPT was 3.44 (95% confidence interval 2.5907-4.5633; p < 0.0001). The sensitivity of preoperative sestamibi and sonography for SGD was 66-100 and 75-82%, respectively. The sensitivity for MGD was 9-67% for both. Intraoperative parathyroid hormone monitoring was utilized in 6 studies. Three studies recommended minimally invasive parathyroidectomy (MIP), while the other 3 recommended bilateral exploration. Conclusion: LAH is a relatively frequent condition among patients on lithium, and calcium monitoring should be performed initially and longitudinally. Almost half of the LAH cases are due to SGD. MIP should be the optimum surgical approach.