Two-Stage Indicators to Assess Learning Curves for Minimally Invasive Ivor Lewis Esophagectomy.

BACKGROUND: Minimally invasive esophagectomy (MIE) Ivor Lewis has been increasingly performed over the last two decades. To guide the implementation of this technically demanding procedure, a comprehensive assessment of MIE-Ivor Lewis learning curves should include both the general competence to accomplish the procedure and the ability to generate oncological benefits. These objectives are believed to be associated with different phases of the learning curve. METHODS: A retrospective review of the first 109 patients who underwent MIE-Ivor Lewis by a single qualified surgeon was conducted. Relevant variables were collected and assessed by regression analysis to identify suitable indicators for patient stratification and learning curve assessment. Thereafter, the differential analysis was performed among groups to validate the learning curve model. RESULTS: Two variables, intrathoracic gastroesophageal anastomosis time and bilateral recurrent laryngeal nerve (RLN) lymphadenectomy number, which plateaued, respectively, after the 26th and 88th cases, were selected as meaningful indicators to identify different competence levels. Therefore, 109 patients were chronologically subcategorized into three groups (the first 26 MIEs as the early group, the next 62 cases as the middle group, and 21 most recent cases as the late group). Perioperative data were compared between groups with positive results to indicate a three-phase model for a learning curve for MIE-Ivor Lewis. CONCLUSIONS: An MIE-Ivor Lewis learning curve should include three discrete phases that indicate, successively, unskilled operation (general competence to accomplish, less proficiency), surgical proficiency, and oncological efficacy. Intrathoracic anastomosis time and bilateral RLN lymphadenectomy were identified as suitable indicators delineate the different stages of an MIE-Ivor Lewis learning curve.

An update on the status of nerve monitoring for thyroid/parathyroid surgery.

PURPOSE OF REVIEW: Recurrent laryngeal nerve (RLN) injury is one of the most common and serious complications associated with thyroid and parathyroid surgery. Although routine visual identification of the RLN is considered the current standard of care, the role of intraoperative neuromonitoring (IONM) of the RLN is more controversial. RECENT FINDINGS: Despite initial enthusiasm that IONM might substantially reduce the rate of RLN injury, most studies failed to show a significant difference in the rate of RLN injury when the use of IONM was compared with visualization of the RLN alone. However, a small number of investigators have reported statistically significant differences in the rates of nerve injury when IONM is used to augment visualization alone, particularly in certain high-risk situations. Despite a lack of conclusive data showing benefit, the use of IONM as an adjunct to visual identification of the RLN has gained increasing acceptance among surgeons. IONM remains an excellent tool to help verify the identity of the RLN, confirm its functional integrity, and pinpoint the site of nerve injury in the event of dysfunction. SUMMARY: The utility of IONM in reducing the rate of RLN injury is largely unproven and remains controversial. However, the use of IONM may be helpful in certain high-risk cases. Promising new technology, such as vagal nerve monitoring, may allow more real-time monitoring of the functional integrity of the RLN and allow the surgeon to react in a timely manner to evolving dysfunction in order to abort maneuvers that may risk definitive injury.

Contribution of intraoperative neural monitoring to preservation of the external branch of the superior laryngeal nerve: a randomized prospective clinical trial.

PURPOSE: The purpose of this study was to evaluate the effect of intraoperative neuromonitoring (IONM) on the injury rate of the external branch of the superior laryngeal nerve (EBSLN) during thyroidectomy. METHODS: A total of 133 consenting patients (98 female, 35 male; mean age, 45.6 ± 11.7 years) undergoing thyroidectomy were randomly assigned to 2 groups. In group 1 (n = 65 patients, 105 nerves), superior thyroid pole dissection was performed with no attempt to identify the EBSLN; in group 2 (n = 68 patients, 106 nerves), IONM was used to identify the EBSLN during surgery. EBSLN function was evaluated by intraoperative electromyography of the cricothyroid muscle. The EBSLN Voice Impairment Index-5 (VII-5) was conducted preoperatively and at 1, 3, and 6 months postoperatively. The primary outcome was the prevalence of EBSLN injury. The secondary outcomes were the identification rate of the EBSLN using IONM and changes in postoperative voice performance. RESULTS: EBSLN injury was detected in eight (12.3%) patients and nine (8.6%) nerves in group 1 and in one (1.5%) patient and one (0.9%) nerve in group 2 (patients, p = 0.015; nerves, p = 0.010). IONM contributed significantly to visual (p < 0.001) and functional (p < 0.001) nerve identification in group 2. The VII-5 indicated more voice changes in group 1 than 2 at 1, 3, and 6 months postoperatively (p = 0.012, p = 0.015, and p = 0.02, respectively). CONCLUSION: IONM contributes to visual and functional identification of the EBSLN and decreases the rate of EBSLN injury during superior pole dissection. Routine use of IONM to identify the EBSLN will minimize the risk of injury during thyroidectomy.

Laryngeal electromyographic changes in postthyroidectomy patients with normal vocal cord mobility.

Thyroidectomy has been used for the treatment of thyroid disease for more than 100 years. In spite of the advancement of surgical techniques, there is still a risk of laryngeal nerve injury. The risk of partial or complete injury still depends on some surgical and disease-related factors. The aim of this study is to show the partial injury and to establish these risk factors via laryngeal electromyographic analysis (LEMG) in postthyroidectomy patients with normal vocal cord motion and mucosal anatomy. Patients who had undergone thyroid surgery were enrolled in this prospective study. LEMG analysis was performed to all patients with normal vocal cord mobility preoperatively and was repeated after the first and the third months of surgery. Thyroarytenoid (TA) and cricothyroid (CT) muscles were used to evaluate recurrent and external branch of superior laryngeal nerves, respectively. Four of the 32 patients had mild-to-moderate degrees of partial LEMG changes during preoperative LEMG analysis of TA and CT muscles on each side. After 3 months of surgery, there was a statistically significant worsening of LEMG findings in the right and left external branches of superior and left recurrent laryngeal nerves. Disease and surgery-related risk factors were analyzed. However, there was no significant relationship on the progression of LEMG findings according to these parameters. This is the first prospective study which supports the risk of progression of LEMG changes in patients with normal laryngoscopic examination after thyroid surgery. No reliable significant risk factor was found influencing the LEMG progression.

Carotid endarterectomy significantly improves postoperative laryngeal sensitivity.

OBJECTIVE: Iatrogenic injury of the vagus nerve or its branches during carotid endarterectomy (CEA) can result in globus sensation, dysphagia, and even vocal fold immobility. Knowledge of morphologic and functional laryngopharyngeal outcomes after CEA is poor. The present study was performed to determine potential iatrogenic damage to the laryngeal innervation after CEA. An area of particular interest was the supraglottic sensory threshold, which was examined by Fiberoptic Endoscopic Evaluation of Swallowing With Sensory Testing (FEESST; Pentax Medical Company, Montvale, NJ), a validated and safe method for the determination of the motor and sensory components of swallowing. METHODS: FEESST was used preoperatively in 32 patients scheduled to undergo CEA and twice postoperatively to examine the motor and sensory components of swallowing. In this endolaryngeal examination, laryngopharyngeal sensory thresholds (in mm Hg) were defined as normal at <4.0 mm Hg air pulse pressure (APP), moderate deficit at 4.0 to 6.0 mm Hg APP, or severe deficit at >6.0 mm Hg APP, with a value >10.0 mm Hg APP indicating abolished laryngeal adductor reflex. Acoustic voice parameters were also analyzed for further functional changes of the larynx. RESULTS: The mean ± standard deviation preoperative FEESST measures showed no significant differences (P = .065) between the operated-on side (6.73 ± 1.73 mm Hg) and the opposite side (5.83 ± 1.68 mm Hg). At 2 days postoperatively, the threshold increased (P = .001) to 7.62 ± 1.98 mm Hg on the operated-on side. A laryngopharyngeal mucosal hematoma on the operated side was endoscopically detectable in eight patients (30.8%); in these patients, we found a markedly elevated (P = .021) measure of 9.50 ± 0.93 mm Hg. On the opposite (nonoperated-on) side of the laryngopharynx, the thresholds remained at the same level as preoperatively over all assessments (P >.05), whereas the differences between the operated and nonoperated-on sides and the hematoma and nonhematoma groups were highly significant (P = .004 and P = .001, respectively). Surprisingly, the sensory threshold on the operated-on side (6.08 ± 2.02 mm Hg) decreased significantly at the 6-week follow-up, even in relation to the preoperative measure (P = .022). With the exception of one patient with permanent unilateral vocal fold immobility, no signs of nerve injury were detected. CONCLUSIONS: In accordance with previous reports, injuries to the recurrent laryngeal nerve during CEA seem to be rare. In most patients, postoperative symptoms (globus, dysphagia, dysphonia) and signs fade within a few weeks without any specific therapeutic intervention. This study shows an improved long-term postoperative superior laryngeal nerve function with regard to laryngopharyngeal sensitivity.

EBSLN and Factors Influencing its Identification and its Safety in Patients Undergoing Total Thyroidectomy: A Study of 456 Cases.

BACKGROUND: The external branch of the superior laryngeal nerve (EBSLN) is at surgical risk during superior thyroid pole ligation during thyroidectomy. Majority of studies have addressed the identification of these nerves and its reported incidence. Very few studies have addressed the relationship of these nerves with the volume of the thyroid gland and presence of toxicity. MATERIALS AND METHODS: A retrospective evaluation of 456 patients who underwent total thyroidectomy were analysed from the prospectively maintained database. The EBSLN was diligently identified and preserved before individual ligation of the superior thyroid pedicle. The nerve was graded as per the Cernea classification (type I, IIa and IIb). Goitres are classified into toxic & non-toxic based on hyperthyroidism, further sub classified as large (>50 cc) and small (≤50 cc) based on volume of each lobe. The grading of EBSLN was correlated with hyperthyroidism and volume of each lobe. RESULTS: In 456 patients (912 nerves), EBSLN was identified in 849/912(93.09%), type I in 156/912(17.1%), type IIa in 522/912(57.23%) and type IIb in 171/912(18.75%). The prevalence of large goitres was 180/912(19.73%).Type IIb nerve was predominantly seen in 161/180(89.4%) of large goitres. Type IIb nerves was more common in toxic 141/372(37.9%) than non-toxic lobes 25/540(5.46%). CONCLUSION: Large goitres are not uncommon in toxic cases. The EBSLN is at highest risk of injury in this subgroup of patients and surgical expertise is essential to identify this entity of EBSLN to perform a safe thyroidectomy.

Use of the Nerve Integrity Monitor during Thyroid Surgery Aids Identification of the External Branch of the Superior Laryngeal Nerve.

BACKGROUND: The external branch of the superior laryngeal nerve (EBSLN) is at risk during thyroid surgery. Despite meticulous dissection and visualization, the EBSLN can be mistaken for other structures. The nerve integrity monitor (NIM) allows EBSLN confirmation with cricothyroid twitch on stimulation. AIMS: The aim of this study was to assess any difference in identification of EBSLN and its anatomical sub-types by dissection alone compared to NIM-aided dissection. METHODS: Routine intra-operative nerve monitoring (IONM) was used, when available, for 228 consecutive thyroid operations (129 total thyroidectomies, 99 hemi-thyroidectomies) over a 10-month period. EBSLN identification by dissection alone (with NIM confirmation of cricothyroid twitch) and by NIM-assisted dissection was recorded prospectively. Anatomical sub-types were defined by the Cernea classification. RESULTS: Of 357 nerves at risk, 97.2 % EBSLNs (95 % confidence interval [CI], 95.5-98.9) were identified by visualization and NIM-aided dissection compared to 85.7 % (95 % CI, 82.1-89.3) identified by dissection alone (<0.001). EBSLN frequency was 34 % for type 1, 55 % for type 2a, and 11 % for type 2b. All identified EBSLNs were stimulated to confirm a cricothyroid twitch after superior thyroid vessel ligation. CONCLUSION: Using the NIM and meticulous dissection of the upper thyroid pole improves EBSLN identification. As the EBSLN is at risk during thyroidectomy and can lead to voice morbidity, the NIM can aid identification of the EBSLN and provide a functional assessment of the EBSLN after thyroid resection.

Severe hoarseness associated with the streamlined liner of the pharyngeal airway (SLIPATM).

Hoarseness is a common post-operative complication in patients who receive general anesthesia. In most cases, the symptoms are temporary and improve within several days. This report describes two patients with prolonged hoarseness following use of the streamlined liner of the pharyngeal airway (SLIPATM). We present the first case of a 56-year-old female patient who developed arytenoid cartilage dislocation resulting in prolonged hoarseness and dysphagia after using a SLIPA™ during a laparoscopic myomectomy. In the second case, we report on a 65-year-old male patient who was scheduled for a laparoscopic cholecystectomy. Left vocal fold paralysis or paresis resulting from recurrent laryngeal nerve injury associated with use of a SLIPA™ caused persistent hoarseness. It should be noted that recurrent laryngeal nerve injury or arytenoid cartilage dislocation are possible complications associated with use of the SLIPATM in case of persistent hoarseness.

[Tapia's syndrome : Rare complication of securing airways]. / Tapia-Syndrom : Seltene Komplikation der Atemwegssicherung.

Nerve injuries are a rare complication of airway management. Two cases of Tapia's syndrome following orotracheal intubation are reported. Case 1: a 23-year-old male patient underwent an otorhinolaryngology (ENT) surgical procedure with orotracheal intubation. A left-sided Tapia's syndrome was verified 3 days later. Case 2: a 67-year-old patient developed a right-sided Tapia's syndrome following an arthroscopic intervention of the left shoulder in the beach-chair position. In both cases there was permanent damage of both nerves. On the basis of a comprehensive literature survey the reasons for an intubation-induced Tapia's syndrome are discussed. In order to avoid a glottis or immediate subglottic position it is recommended to check and to document the position of the cuff (depth of intubation) and the measured cuff pressure immediately after intubation. It also seems to be advisable to document an overstretched head position if required for the operation.

Preoperative diagnosis and intraoperative protection of nonrecurrent laryngeal nerve: a review of 5 cases.

BACKGROUND: Nonrecurrent laryngeal nerve (NRLN) is a risk factor for nerve injury during thyroidectomy or parathyroidectomy. It is usually associated with abnormal vasculature that can be identified by several imaging methods. The aim of this study was to retrospectively analyze the preoperative diagnosis and intraoperative protection of NRLN. MATERIAL AND METHODS: Of the 7169 patients who underwent thyroid surgery at our hospital between August 2008 and January 2013, 5 patients with NRLN were identified. Preoperative chest X-rays, neck ultrasonography (US), and computed tomography (CT) findings were reviewed. NRLNs were carefully and systematically searched for in surgery. RESULTS: Preoperative CT predicted NRLN in all 5 cases (100% accuracy). The detection rate of NRLN by CT was 0.4% (5/1170). NRLNs were confirmed in surgery. All of them were right-sided NRLN with type IIA variant. The CT scans clearly revealed the vascular anomalies. The review of US images suggested that vascular anomalies could be identified on the images in 1 patient. No postoperative complications occurred in any patient. CONCLUSIONS: The preoperative CT scan was a reliable and effective method for identifying abnormal vasculature to indirectly predict NRLN. Combining the CT and US findings with adequate surgical technique may help to reduce the risk of nerve damage, in addition to preventing nerve palsy.

Nodal recurrence in the lateral neck after total thyroidectomy with prophylactic central neck dissection for papillary thyroid cancer.

PURPOSE: The aim of this study was to examine risk factors for nodal recurrence in the lateral neck (NRLN) in patients with papillary thyroid cancer (PTC) who underwent total thyroidectomy with prophylactic central neck dissection (TT + pCND). METHODS: This was a retrospective cohort study of patients with PTC who underwent TT + pCND. Data of all patients treated over a 10-year period (between 1998 and 2007) were analysed. The primary outcome was prevalence of NRLN within the 5-year follow-up after initial surgery. Predictors of NRLN were determined in the univariable and multivariable analysis. RESULTS: Of 760 patients with PTC included in this study, 44 (6.0 %) developed NRLN. In the univariable analysis, the following factors were identified to be associated with an increased risk of NRLN: positive/negative lymph node ratio ≥0.3 (odds ratio (OR) 14.50, 95 % confidence interval (CI) 7.21 to 29.13; p < 0.001), central lymph node metastases (OR 7.47, 95 % CI 3.63 to 15.38; p < 0.001), number of level VI lymph nodes <6 in the specimen (OR 2.88, 95 % CI 1.21 to 6.83; p = 0.016), extension through the thyroid capsule (OR 2.55, 95 % CI 1.21 to 5.37; p = 0.013), localization of the tumour within the upper third of the thyroid lobe (OR 2.35, 95 % CI 1.27 to 4.34; p = 0.006) and multifocal lesions (OR 1.85, 95 % CI 1.01 to 3.41; p = 0.048). CONCLUSIONS: Central lymph node metastases together with positive to negative lymph node ratio ≥0.3 represent the strongest independent prognostic factors for the PTC recurrence in the lateral neck.

Coexisting right nonrecurrent and right recurrent inferior laryngeal nerves: a rare and controversial entity: report of a case and review of the literature.

Variations in the course of the recurrent laryngeal nerve (RLN) can occur, including the development of a nonrecurrent inferior laryngeal nerve (NRILN). Rarely, both a right RLN and a right NRILN have been reported in the same patient, merging before they enter the larynx. A case is presented, including images, and the literature concerning this rare anatomical finding is reviewed, including studies suggesting alternative explanations for these cases. Fourteen previously reported cases of coexisting RLN and NRILN were identified, all involving the right side. Some cases were associated with an anomalous origin of the right subclavian artery and some were not. The alternative explanations that a communicating branch of the sympathetic nerve, which joins the RLN, is mistaken for an NRILN or that a collateral branch from an NRILN is mistaken for an RLN in these cases are also considered. Surgeons must be aware of these unusual variations to minimize nerve injury during neck surgery.

Anaesthesia for massive retrosternal thyroidectomy in a tertiary referral centre.

BACKGROUND: Retrosternal goitre (RSG) is an uncommon problem encountered rarely by anaesthetists working outside specialized head and neck (H&N) surgical units. Traditional anaesthetic teaching warns of difficult airway management in these patients. The incidence and extent of these problems is unclear. METHODS: We have performed a retrospective review of the anaesthetic management all patients with massive RSG (extending to the aortic arch or beyond) presenting for thyroidectomy at University Hospital Aintree from January 2007 to May 2012. RESULTS: Five hundred and seventy-three patients underwent a thyroidectomy procedure at Aintree University Hospitals NHS Foundation Trust (AUH) between January 2007 and May 2012. Of these, 34 cases were documented as having a RSG. Review of each patient's preoperative computerized tomography imaging identified 19 patients with massive RSG. There was one case of failed intubation. All other patients underwent uneventful tracheal intubation via direct laryngoscopy. All glands were removed through the neck with no requirement to proceed to sternotomy. There were no instances of postoperative respiratory problems or tracheomalacia. Three patients suffered recurrent laryngeal nerve (RLN) injuries. CONCLUSION: When managed within a dedicated H&N operating theatre we have found a low incidence of difficult tracheal intubation, difficult mechanical ventilation nor postoperative respiratory difficulties in patients with massive RSG and mid-tracheal compression because of benign multi-nodular goitre. Surgical complications, however, are more frequent than those associated with cervical thyroidectomy with RLN injury and postoperative bleeding more likely.

Normative intra-operative electrophysiologic waveform analysis of superior laryngeal nerve external branch and recurrent laryngeal nerve in patients undergoing thyroid surgery.

BACKGROUND: Injury to the external branch of the superior laryngeal nerve (EBSLN) can occur during superior pole dissection in thyroid surgery; the EBSLN injury rate is reported as high as 28 % (Cernea et al., Head Neck 14:380-383, 1992). Injury to the EBSLN leads to variable symptoms that may be overlooked, but that can be significant, especially to professional speakers and singers. Intraoperative nerve monitoring (IONM) is employed widely to aid in nerve identification. We report on normative electroneuromyography (EMG) data on EBSLN-IONM and cricothyroid muscle (CTM) twitch response during stimulation as an aid to EBSLN identification. METHODS: A prospective study of the SLN and the recurrent laryngeal nerve (RLN) IONM data in 72 consecutive thyroid surgeries was carried out. All patients underwent preoperative and postoperative laryngeal exams, and patients with abnormal preoperative laryngeal function were excluded. Normative EMG data and CTM twitch response during EBSLN stimulation were recorded and analyzed. RESULTS: Stimulation of the EBSLN resulted in a positive CTM twitch response in 100 %, whereas EMG response was recordable in 80 %. Electromyographic amplitude was ~1/3 of ipsilateral RLN amplitude and did not change through the case with multiple stimulations. Stimulation of the EBSLN was similar for men and women and at 1 and 2 mA stimulation levels. CONCLUSIONS: Intraoperative nerve monitoring of the EBSLN aids in EBSLN identification and provides electroneuromyographic information in 80 % of cases. The laryngeal head of the sternothyroid muscle is a useful landmark to locate EBSLN.

Neuromonitoring in thyroidectomy: a meta-analysis of effectiveness from randomized controlled trials.

Neuromonitoring in thyroid surgery has been employed to make nerve identification easier and decrease the rates of laryngeal nerve injuries. Several individual randomized controlled trials (RCTs) have been published, which did not identify statistical differences in the rates of recurrent laryngeal nerve (RLN) or external branch of the superior laryngeal nerve (EBSLN) injuries. The objective of this report is to perform meta-analysis of the combined results of individual studies to measure the frequency of RLN and EBSLN injuries in patients who underwent thyroidectomy with routine neuromonitoring in comparison with common practice of search and identification. RCTs comparing routine neuromonitoring versus no use in patients who underwent elective partial or total thyroidectomy were evaluated. Outcomes measured were temporary and definitive palsy of the RLN and EBSLN. A systematic review and meta-analysis was done using random effects model. GRADE was used to classify quality of evidence. Six studies with 1,602 patients and 3,064 nerves at risk were identified. Methodological quality assessment showed high risk of bias in most items. Funnel plot did not reveal publication bias. The risk difference for temporary RLN palsy, definitive RLN palsy, temporary EBSLN palsy, and definitive EBSLN palsy were -2% (95% confidence interval -5.1 to 1); 0% (-1 to 1); -9% (-15 to -2) and -1% (-4 to 2), respectively. Quality was rated low or very low in most outcomes due to methodological flaws. Meta-analysis did not demonstrate a statistically significant decrease in the risk of temporary or definitive RLN injury and definitive EBSLN injury with the use of neuromonitoring. The neuromonitoring group had a statistically significant decrease in the risk of temporary EBSLN injury.

Neuromonitoring of the laryngeal nerves in thyroid surgery: a critical appraisal of the literature.

One of the most significant complication of thyroid surgery is injury of the recurrent laryngeal nerve. Injury of the external branch of the superior laryngeal nerve is a less obvious but occasionally significant problem. Recently, neuromonitoring during thyroidectomy has received considerable attention because of literature encouraging its use, but there is no consensus about its advantages and utility. A critical assessment of the literature on neuromonitoring was conducted in order to define its effectiveness, safety, cost-effectiveness and medical-legal impact. Available data does not show results superior to those obtained by traditional anatomical methods of nerve identification during thyroid surgery. Data about cost-effectiveness is scarce. The literature shows inconsistencies in methodology, patient selection and randomization in various published studies which may confound the conclusions of individual investigations. The current recommendation for use in "high risk" patients should be assessed because definition heterogeneity makes identification of these patients difficult. As routine use of neuromonitoring varies according to geography, its use should not be considered to be the standard of care.

Cervical tracheal transection after scarf entanglement in a go-kart engine.

BACKGROUND: Tracheal disruption secondary to blunt force occurs infrequently. Most individuals suffering such an injury die before arriving at a hospital. Diagnosis for those who do present alive is often delayed, as signs and symptoms typically do not match the severity of injury. OBJECTIVE: The objectives of this case report are to present a unique mechanism for tracheal disruption and to discuss our management strategy. CASE REPORT: We describe an 18-year-old man who suffered tracheal disruption after entanglement of his scarf in a go-kart engine. His initial workup was conducted by emergency physicians and included computed tomographic evaluation of the neck. After diagnosis, the patient was transported to an operating suite. Awake tracheostomy was performed in this controlled environment to secure the airway, after which the trachea was repaired via primary anastomosis. CONCLUSIONS: Prompt recognition and appropriate intervention are critical in the care of patients with suspected tracheal transection to prevent mortality.

A detailed study of the relationship between the external laryngeal nerve and superior thyroid artery, including its glandular branches.

The external layrngeal nerve (ELN) may be at risk during thyroidectomy. Because the relationship between the ELN and superior thyroid artery (STA) can be variable, we aimed to investigate their relationship in detail. In human cadavers, 81 ELN and STA and their branches were carefully dissected. The position of the nerve was classified as medial (Group I, on 76.5% sides), lateral (Group II, on 20.9% sides), or posterior (Group III, on 2.4% sides) to the origin of the STA. In Group Ia, the nerve did not cross the artery while it did cross the artery in Group Ib. In Group II, the nerve was located lateral to the origin of the artery and crossed it. In Group III, the nerve coursed downward posterior to the artery. In conclusion, the topography of the ELN showed much more variability in its relationship to the STA than is described in the literature. Such variations should be kept in mind during surgery of the anterior neck. It is our hope that such data will decrease surgical morbidity following surgery of the anterior neck.

Vagus nerve stimulation for standardized monitoring: technical notes for conventional and endoscopic thyroidectomy.

Standardization of the intraoperative neuromonitoring (IONM) technique is an essential aspect of modern monitored thyroid surgery. The standardized technique involves vagal nerve stimulation. VN stimulation is useful for technical problem solving, detecting non-recurrent laryngeal nerve (non-RLN), recognizing any recurrent laryngeal nerve (RLN) lesions, and precisely predicting RLN postoperative function. Herein, we present technical notes for the VN identification to achieve the critical view of safety of the VN stimulation with or without dissection.

Assessment of different classification systems for predicting the risk of superior laryngeal nerve injury during thyroid surgery: a prospective cohort study.

Background: A multitude of anatomical variations have been noted in the external branch of the superior laryngeal nerve (EBSLN). In this study, intraoperative neuromonitoring (IONM) was used to assess the potential value of the different classical EBSLN classifications for predicting the risk of EBSLN injury. Methods: In total, 136 patients with thyroid nodules were included in this prospective cohort study, covering 242 nerves at risk (NAR). The EBSLN was identified by observing the cricothyroid muscle twitch and/or typical electromyography (EMG) biphasic waveform. The EBSLNs were classified by Cernea classification, Kierner classification, and Friedman classification, respectively. The EMG parameters and outcomes of vocal acoustic assessment were recorded. Results: The distribution of Cernea, Kiernea, and Friedman subtypes were, respectively, Cernea 1 (40.9%), Cernea 2A (45.5%), Cernea 2B (10.7%), Kierner 1 (40.9%), Kierner 2 (45.5%), Kierner 3 (10.7%), Kierner 4 (2.9%) and Friedman 1 (15.7%), Friedman 2 (33.9%), Friedman 3 (50.4%). The amplitudes of EBSLN decreased significantly after superior thyroid pole operation, respectively, in Cernea 2A (193.7 vs. 226.6µV, P=0.019), Cernea 2B (185.8 vs. 221.3µV, P=0.039), Kierner 2 (193.7vs. 226.6µV, P=0.019), Kierner 3 (185.8 vs. 221.3µV, P=0.039), Kierner 4 (126.8vs. 226.0µV, P=0.015) and Friedman type 2 (184.8 vs. 221.6µV, P=0.030). There were significant differences in Fmax and Frange for Cernea 2A (P=0.001, P=0.001), 2B (P=0.001, P=0.038), Kierner 2 (P=0.001), Kierner 3 (P=0.001, P=0.038), and Friedman 2 (P=0.004, P=0.014). In the predictive efficacy of EBSLN injury, the Friedman classification showed higher accuracy (69.8% vs. 44.3% vs. 45.0%), sensitivity (19.5% vs. 11.0% vs. 14.0%), and specificity (95.6% vs. 89.9% vs. 89.9%) than the Cernea and Kierner classifications. However, the false negative rate of Friedman classification was significantly higher than other subtypes (19.5% vs. 11.0% vs. 14.0%). Conclusion: Cernea 2A and 2B; Kierner 2, 3, and 4; and Friedman 2 were defined as the high-risk subtypes of EBSLN. The risk prediction ability of the Friedman classification was found to be superior compared to other classifications.