Is identification and dissection of the external laryngeal nerve necessary during thyroidectomy? A prospective study.

BACKGROUND: Compared to the recurrent laryngeal nerve, the EBSLN (or external laryngeal nerve) is less studied in terms of its course and relationship with the thyroid gland. This is a prospective intraoperative study designed to identify the anatomical variations of the EBSLN in relation to the IPC, the superior thyroid pedicle, and the point where the nerve crosses the STA. Additionally, the study aims to propose a technical procedure for its preservation. METHODS: We conducted a prospective study of 50 patients (total of 100 nerves) undergoing total thyroidectomy at the Department of Surgery 'B' in Ibn Sina Hospital, Rabat. Intraoperatively, the EBSLN was visually identified and preserved before ligating the superior thyroid vessels. Each nerve was categorized using established classification systems. RESULTS: The overall pooled EBSLN identification rate was 82%. Cernea type IIa (nerves crossing the STA less than 1 cm above the upper edge of the superior thyroid pole) and Friedman type II (nerves piercing the lower fibers of the IPC) were the most prevalent (64% and 44%, respectively). Kierner type IV (nerves crossing the branches of the STA immediately above the upper pole of the thyroid gland) was represented in 27% of cases. CONCLUSION: A better understanding of surgical anatomy of the neck allows for better results of thyroidectomy by preserving the external and recurrent laryngeal nerves.

Study on Microsurgical Anatomy of External Branch of Superior Laryngeal Nerve Related to Carotid Endarterectomy.

OBJECTIVE: To explore the methods of protecting the external branch of the superior laryngeal nerve during carotid endarterectomy through microsurgical anatomic study of the external branch of the superior laryngeal nerve in cadaveric specimens. METHODS: A total of 30 cadaveric specimens (60 sides) were dissected to measure the thickness of the external branch of the superior laryngeal nerve. A triangular area was exposed, bounded by the lower border of the digastric muscle superiorly, the medial edge of the sternocleidomastoid muscle laterally, and the upper border of the superior thyroid artery inferiorly. The probability of the occurrence of the external branch of the superior laryngeal nerve in this area was observed and recorded. The distance among the midpoint of the external branch of the superior laryngeal nerve in this area with the tip of the mastoid process and the angle of the mandible as well as the bifurcation of the common carotid artery was measured and recorded. RESULTS: Among 30 specimens of cadaveric heads (60 sides) examined 53 external branches of the superior laryngeal nerve were observed while 7 were absent. Of the 53 branches observed, 5 were located outside the anatomic triangle region mentioned above, while the remaining 48 branches were located within the anatomic triangle region with a probability of ~80%. The thickness of the midpoint of the external branches of the superior laryngeal nerve within the anatomic triangle region was 0.93 mm (0.72-1.15 mm [±0.83 SD]), located 0.34 cm [-1.62-2.43 cm (±0.96 SD)] posterior to the angle of the mandible, 1.28 cm (-1.33 to 3.42 cm (±0.93 SD)] inferiorly; 2.84 cm (0.51-5.14 cm±1.09 SD) anterior to the tip of the mastoid process, 4.51 cm (2.82-6.39 cm±0.76 SD) inferiorly; 1.64 cm [0.57-3.78 cm (±0.89 SD)] superior to the bifurcation of the carotid artery. CONCLUSIONS: During carotid endarterectomy procedure, using the cervical anatomic triangle region, as well as the angle of the mandible, the tip of the mastoid process, and the bifurcation of the carotid artery as anatomic landmarks, is of significant clinical importance for protecting the external branches of the superior laryngeal nerve.

Transection Of Sternothyroid Muscle Increases The Rate Of Exposure Of The External Branch Of The Superior Laryngeal Nerve During Thyroidectomy.

Objectives: To assess the benefits of transection of the sternothyroid muscle compared to conventional approach for detecting the external branch of the superior laryngeal nerve while dealing with the upper pole of the thyroid gland. METHODS: The randomised controlled clinical trial was conducted at Kafrelsheikh University Hospital, Egypt, from January 2021 to January 2022, and comprised patients who were eligible for total thyroidectomy and met the American Thyroid Association guidelines. They were randomised and divided into conventional approach group A and sternothyroid muscle transection approach group B. The rate of exposure of the external branch of the superior laryngeal nerve, injury, classification, operative time and voice outcomes at 2 weeks and 3 months post-intervention were noted in both the groups. Data was analysed using SPSS 22. RESULTS: Of the 102 patients, 50(49%) were in group A; 5(10%) males and 45(90%) females with mean age 40.48±12.58 years and mean body massindex 30.676±2.305. There were 52(51%) patientsin group B; 5(9.6%) males and 45(90.4%) females with mean age 39.67±11.60 years and mean body mass index 30.096±2.776. The rate of external branch of the superior laryngeal nerve identification was higher and the operative time was shorter in group B compared to group A (p=0.05). No significant difference was noted in terms of voice outcomes either at baseline or at any of the two follow-up points between the groups (p>0.05). CONCLUSIONS: The transection of sternothyroid muscle improved the rate of external branch of the superior laryngeal nerve exposure and preservation compared to the conventional technique during thyroidectomy.

Anatomical and functional identification of the external branch of the superior laryngeal nerve: classification based on morphology and electrophysiological monitoring.

BACKGROUND: Motor function of the external branch of superior laryngeal nerve (EBSLN) is vital for voice quality. We studied the rate of EBSLN identification and integrity in the era of intraoperative neuromonitoring (IONM). METHODS: Anatomic and functional identification of 515 EBSLNs-at-risk was performed under the guidance of IONM that motor integrity was electrophysiologically checked. The functional integrity was assessed with crico-thyroid muscle (CTM) twitches and/or recordable waveform amplitude. We tried to establish the systematic classification of EBSLN identification and integrity. RESULTS: Visual, electrophysiological and total identification rates were 64.3%, 31.6% and 95.9%, respectively. We could identify 4.1% of EBSLNs neither anatomically nor electrophysiologically. We recorded CTM twitches alone or both CTM twitches and wave amplitude in 203(39.4%) and 291(56.5%) branches respectively. Identification features of EBSLNs were systematically classified under three main types: Visualized-monitored (1), non-visualized-monitored (2), unidentified (3), and electrophysiological integrity of EBSLNs under two subtypes: CTM twitches alone (a) and CTM twitches and wave amplitude (b). CONCLUSION: Dedicated thyroid surgeon could visually identify EBSLNs. IONM contribution significantly increases the identification rate. Systematic classification of identification and electrophysiological integrity of EBSLNs may increase comprehensive knowledge about its motor function that is crucial for complication-free thyroidectomy.

Swallowing dysfunction following surgery for well-differentiated thyroid cancer with extrathyroid invasion.

BACKGROUND: Differentiated thyroid carcinoma (DTC) can invade the surrounding aerodigestive tract. Radical surgery for locally advanced DTC will require resection of the trachea, recurrent laryngeal nerve (RLN), inferior pharyngeal constrictor muscles (IPCMs), or a part of the esophagus. The purpose of this study was to demonstrate the effect of resection of these surrounding tissues combined with total thyroidectomy and neck dissection on swallowing function following surgery. METHODS: We performed total thyroidectomy combined with neck dissection and resection of the RLN in 24 patients with DTC with extrathyroidal invasion (19 unilateral, 1 bilateral), IPCMs (n = 5), or muscle layers of esophagus (n = 9). Nine patients received a tracheostomy placement due to a window resection of the trachea for tumor invasion (n = 6) and necessary upper airway management (n = 3). We used the duration of nasogastric tube feeding to evaluate swallowing function following surgery. RESULTS: Patients who underwent tracheostomy or IPCM resection showed significantly longer periods of tube feeding (p = 0.0057 and 0.0017, respectively). In contrast, resection of the unilateral RLN or esophageal muscle layer showed no difference in tube feeding duration. Multiple regression analysis indicated that tracheostomy and IPCM resection were significant independent predictors of longer periods of tube feeding (p = 0.04583 and 0.00087, respectively). CONCLUSION: These results indicate that tracheostomy placement and resection of the IPCMs, together with total thyroidectomy, extends the tube feeding duration in the postoperative period.

A Surgical Mouse Model for Advancing Laryngeal Nerve Regeneration Strategies.

Iatrogenic recurrent laryngeal nerve (RLN) injury is a morbid complication of anterior neck surgical procedures. Existing treatments are predominantly symptomatic, ranging from behavioral therapy to a variety of surgical approaches. Though laryngeal reinnervation strategies often provide muscle tone to the paralyzed vocal fold (VF), which may improve outcomes, there is no clinical intervention that reliably restores true physiologic VF movement. Moreover, existing interventions neglect the full cascade of molecular events that affect the entire neuromuscular pathway after RLN injury, including the intrinsic laryngeal muscles, synaptic connections within the central nervous system, and laryngeal nerve anastomoses. Systematic investigations of this pathway are essential to develop better RLN regenerative strategies. Our aim was to develop a translational mouse model for this purpose, which will permit longitudinal investigations of the pathophysiology of iatrogenic RLN injury and potential therapeutic interventions. C57BL/6J mice were divided into four surgical transection groups (unilateral RLN, n = 10; bilateral RLN, n = 2; unilateral SLN, n = 10; bilateral SLN, n = 10) and a sham surgical group (n = 10). Miniaturized transoral laryngoscopy was used to assess VF mobility over time, and swallowing was assessed using serial videofluoroscopy. Histological assays were conducted 3 months post-surgery for anatomical investigation of the larynx and laryngeal nerves. Eight additional mice underwent unilateral RLN crush injury, half of which received intraoperative vagal nerve stimulation (iVNS). These 8 mice underwent weekly transoral laryngoscopy to investigate VF recovery patterns. Unilateral RLN injury resulted in chronic VF immobility but only acute dysphagia. Bilateral RLN injury caused intraoperative asphyxiation and death. VF mobility was unaffected by SLN transection (unilateral or bilateral), and dysphagia (transient) was evident only after bilateral SLN transection. The sham surgery group retained normal VF mobility and swallow function. Mice that underwent RLN crush injury and iVNS treatment demonstrated accelerated and improved VF recovery. We successfully developed a mouse model of iatrogenic RLN injury with impaired VF mobility and swallowing function that can serve as a clinically relevant platform to develop translational neuroregenerative strategies for RLN injury.

Patent ductus arteriosus closure and somatic regional oxyhemoglobin saturation.

The authors report a case of a 14-day-old infant patient with patent ductus arteriosus (PDA) with pulmonary hypertension. Accidental clipping of the left pulmonary artery (LPA) during intended PDA closure was revealed, and subsequent urgent PDA closure and releasing a clip of the LPA were conducted. During surgeries we measured somatic regional oxyhemoglobin saturation (rSO2) values and change in those might be a key for early diagnosis of accidental clipping of the LPA. These findings suggest that we should understand the risk of accidental closure of the LPA during PDA surgery and somatic rSO2 values will provide information for early diagnosis of critical complication.

Selective laryngeal reinnervation: can rerouting of the thyrohyoid nerve simplify the procedure by avoiding the use of a nerve graft?

PURPOSE: The objective of this study was to record the descriptive and metric anatomical characteristics of the thyrohyoid nerve with the aim of rerouting it in a selective laryngeal reinnervation procedure. METHODS: An anatomical study was performed on ten formalin-embalmed cadavers. The origin of the thyrohyoid nerve and the superior root of the ansa cervicalis, the location of the thyrohyoid nerve ending in the thyrohyoid muscle, and the recurrent laryngeal nerve were established. Then, a rerouting of the thyrohyoid nerve was performed. We measured the length of thyrohyoid nerve, the distance between the thyrohyoid nerve ending and the recurrent laryngeal nerve at the horizontal level of the cricothyroid joint before and after the rerouting, and the distance between the origin of the thyrohyoid nerve and the superior root of the ansa cervicalis. RESULTS: The thyrohyoid nerve was identified on both sides in all the cases. The average length of the thyrohyoid nerve was 27 mm. The end of the thyrohyoid nerve was found in 100% of the cases at the upper outer quarter of the thyrohyoid muscle. After the rerouting, an average reduction of 30% of the distance between the end of the thyroid nerve and the recurrent laryngeal nerve at the horizontal level of the cricothyroid joint was measured. CONCLUSION: The rerouting of the thyrohyoid nerve provided a reduction in the length of the nerve graft in laryngeal reinnervation. Moreover, the constancy of the thyrohyoid nerve and its characteristics make it a valuable anatomical base for laryngeal reinnervation and laryngeal innervated allotransplantation.

Activation of TRPV1 and TRPM8 Channels in the Larynx and Associated Laryngopharyngeal Regions Facilitates the Swallowing Reflex.

The larynx and associated laryngopharyngeal regions are innervated by the superior laryngeal nerve (SLN) and are highly reflexogenic. Transient receptor potential (TRP) channels have recently been detected in SLN innervated regions; however, their involvement in the swallowing reflex has not been fully elucidated. Here, we explore the contribution of two TRP channels, TRPV1 and TRPM8, located in SLN-innervated regions to the swallowing reflex. Immunohistochemistry identified TRPV1 and TRPM8 on cell bodies of SLN afferents located in the nodose-petrosal-jugular ganglionic complex. The majority of TRPV1 and TRPM8 immunoreactivity was located on unmyelinated neurons. Topical application of different concentrations of TRPV1 and TRPM8 agonists modulated SLN activity. Application of the agonists evoked a significantly greater number of swallowing reflexes compared with the number evoked by distilled water. The interval between the reflexes evoked by the agonists was shorter than that produced by distilled water. Prior topical application of respective TRPV1 or TRPM8 antagonists significantly reduced the number of agonist-evoked reflexes. The findings suggest that the activation of TRPV1 and TRPM8 channels present in the swallowing-related regions can facilitate the evoking of swallowing reflex. Targeting the TRP channels could be a potential therapeutic strategy for the management of dysphagia.

Identification of the External Branch of the Superior Laryngeal Nerve during Thyroid Surgery.

AIM: To compare the level of intra-operative identification of external branch of the superior laryngeal nerve (EBSLN) through classical conventional clinical methods of prevention against those applying intraoperative neuromonitoring (IONM). MATERIALS AND METHODS: The study included 102 patients with interventions on the thyroid gland performed in the surgical clinics of St George University Hospital and the Department of Special Surgery of Plovdiv Medical University. All operative procedures were performed by the standard technique of capsular dissection and IONM. RESULTS: Of all 102 thyroid procedures 87 (85.3%) patients underwent total thyroidectomy and 15 (14.7%) had unilateral thyroid lobectomy. One hundred fifty-five (82.01%) out of 189 expected EBSLN were identified and investigated intraoperatively when trying to identify visually EBSLN by the so called classical (conventional) methods of prevention. With the use of IONM, 181 (96.76%) EBSLN were correctly identified. Compared to the preliminary results of visual identification - 155/189 (82.01%) EBSLN, the degree of identification of EBSLN through IONM reached 96.76% which is a statistically significant difference (P <0.05) Conclusion: The use of IONM during thyroid resection significantly improves the degree of identification of EBSLN compared to conventional means of prevention. Routine use of IONM in surgical interventions on the thyroid gland will be beneficial for more secure identification and prevention of EBSLN.

The Identification, Preservation and Classification of the External Branch of the Superior Laryngeal Nerve in Thyroidectomy.

BACKGROUND: Avoiding injury to the external branch of the superior laryngeal nerve is one of the major challenges during thyroid operation. The aim of this study was to propose a practical classification of the external branch of the superior laryngeal nerve. METHODS: A retrospective study of total thyroidectomy was performed. Totally 240 patients were included, with 480 external branches of the superior laryngeal nerves explored by intraoperative neuromonitoring. The classification of the external branch of the superior laryngeal nerve was determined by the distance between the upper edge of the superior thyroid pole and the lowest point of the nerve when the thyroid lobe was retracted in the lateral and inferior direction. Multinomial logistic regression analysis was run to predict the type of the nerve from several variables. RESULTS: The identification rate of the external branch of the superior laryngeal nerve was 98.54% (473 of 480 nerves). Higher ratio of longitudinal size of the thyroid lobe to ipsilateral neck length increased the likelihood of that both the type 2 and 3 nerve with respect to type 1 nerve, with OR 2.72, 95% CI = 1.21-6.12 and OR 5.30, 95% CI = 2.09-13.44, respectively. (1a) The nerve whose lowest point (entry into the muscle) was located more than 1 cm above the horizontal plane passing the upper border of superior thyroid pole. (1b) The nerve whose lowest point (the point right above the superior thyroid pole) was located more than 1 cm above the plane. (2a) The nerve whose lowest point (entry into the muscle) was located within 1 cm above the plane. (2b) The nerve whose lowest point (the point right above the superior thyroid pole) was located within 1 cm above the plane. (3a) The nerve whose lowest point (entry into the muscle) was located below the plane. (3b) The nerve whose lowest point (the point right below the superior thyroid pole) was located anterior to the gland. (3c) The nerve whose lowest point (the point right below the superior thyroid pole) was located posterior to the gland. CONCLUSIONS: Identification rate of the external branch of the superior laryngeal nerve by intraoperative neuromonitoring was significantly high. Understanding the new practical classification of the nerve allows for better identification and function preservation of this nerve during thyroidectomy.

Recognition and Surgical Techniques for Management of Nonrecurrent Laryngeal Nerve during Carotid Endarterectomy.

The presence of a nonrecurrent laryngeal nerve (NRLN) during carotid endarterectomy (CEA) may significantly limit the exposure of the surgical field during this operation. Although its reported incidence is rare, NRLN typically overlies the carotid bifurcation and failure to recognize this anatomic variation increases the risk of NRLN injury. A retrospective chart review of all patients who underwent CEA for hemodynamically significant extracranial carotid stenosis between January 2005 and December 2014 was performed. All patients with NRLN encountered intraoperatively were identified. Clinical outcomes, surgical techniques, and complications were reviewed and reported. Four left-sided NRLN were identified and 4 were right sided. No cranial nerve deficits or injuries occurred after CEA in patients where NRLN was encountered. Two distinct surgical techniques were used to manage patients with NRLN and they are discussed in detail.

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.

Proposal for anatomical classification of the superior pole in thyroid surgery.

OBJECTIVE: To propose a distinct anatomical classification for the superior thyroid pole that may serve as a surgical landmark and could help reduce complications in thyroid surgery. MATERIALS AND METHODS: A comprehensive anatomical study based on existing literature and surgical observations. RESULTS: The proposed superior pole classification is based on two parameters that closely interact: one is the shape of the superior pole and the other is the structure of the vascular pedicle of the superior pole. We have come up with three distinct types of superior thyroid pole anatomical structure that may be predictive of the risk for both hemorrhage and nerve injury. CONCLUSIONS: Superior pole classification may serve as a guiding tool during thyroid surgery in order to reduce complications such as bleeding and injury to the external branch of the superior laryngeal nerve.

Recurrent Laryngeal Nerve Paralysis after Esophagectomy: Respiratory Complications and Role of Nerve Reconstruction.

Recurrent laryngeal nerve paralysis (RLNP) after esophagectomy is a common complication and associated with aspiration pneumonia. In this study, we assessed the risk of RLNP and the usefulness of immediate reconstruction of recurrent laryngeal nerve (RLN) to prevent respiratory complications after esophagectomy. Seven hundred and eighty-two consecutive patients underwent an esophagectomy with three-field lymph node dissection, simultaneous gastric conduit reconstruction, and cervical anastomosis. Vocal cord function was observed using a flexible laryngoscope. Reconstruction between RLN and ipsilateral vagus nerve was performed during esophagectomy. RLNP was observed in 229 (29.3%) of the patients after esophagectomy: 198 unilateral and 31 bilateral cases. Of the 198 unilateral RLNP, vocal cord paralysis was observed predominantly on the left side (82.7%). RLNP was significantly associated with postoperative respiratory complications (P < 0.001) requiring a tracheotomy (P < 0.001) and mechanical ventilation (P < 0.001) and was also associated with esophagogastric anastomotic leakage (P = 0.015); consequently, the postoperative hospital stay was longer for patients with RLNP (P < 0.001). A longer operation time (P < 0.001) and advanced age (P = 0.038) were identified as significant independent predictors of RLNP. Resection of the RLN together with metastatic nodes was performed in 29 cases. The patients underwent RLN reconstruction (n = 11) had a significantly shorter postoperative hospital stay than those without RLN reconstruction (n = 18) (P = 0.019). In conclusion, RLNP was related to a poorer postoperative course among patients undergoing an esophagectomy. New surgical technologies are recommended for prevention of RLNP.

Surgical treatment of bronchial asthma by resection of the laryngeal nerve.

BACKGROUND: Management of asthma in chronically affected patients is a serious health problem. Our aim was to show that surgical treatment of chronic bronchial asthma by unilateral resection of the internal branch of the superior laryngeal nerve (ib-SLN) is an adequateand lasting remedial response. PATIENTS AND METHODS: In a retrospective study, 41 (26 male and 15 female) patients with bronchial chronic asthma were treated surgically during the period between 2005 and 2013. It consisted of a unilateral resection of the ib-SLN under optical zoom, on patients placed in supinator position. 35 patients (24 male and 11 female) who were un-operated were included as a control. RESULTS: In all patients, medication was reduced progressively. When the results were compared with the control group, it was seen that in 26% of the patients, both forced expiratory volume (FEV) and peak expiratory flow (PEF) increased significantly (p <05) and only modestly in 53.6% of patients (FEV, p <05 and PEF, p <05). In the remaining 20% of patients, these parameters remained however unchanged. Overall, in 80% of patients unilateral resection of the ib-SLN gave satisfactory results because it shortened the intervals and duration of asthmatic attacks, rendering thereby a reduction in medication. CONCLUSION: This minimal-invasive method helped prevent/cure asphyxias in chronic bronchial asthma without affecting cough reflex,respiratory control and phonation and it helped patients avoid severe crisis. This approach is of interest for patients with severe and/or uncontrolled bronchial asthma in settings with limited access to drug treatment.

Ansa Cervicalis External Branch Anastomosis to Restore High Tone Voice in Thyroid Surgery.

OBJECTIVES: Injury to the external branch of the superior laryngeal nerve (EBSLN) causes low-pitch voice and voice fatigue, particularly in female subjects, and available treatments are limited. Here, we assess a novel surgical procedure to restore a high-tone voice: ansa cervicalis to EBSLN anastomosis (A-E anastomosis). METHODS: Between November 2012 and April 2022, 13 patients (12 female) underwent unilateral EBSLN resection and A-E anastomosis, while 20 (16 female) underwent EBSLN resection during thyroid surgery. Patients (4494 women and 1025 men) with normal laryngoscopy scheduled for thyroid surgery served as normal controls. Phonatory function was examined using a Phonation Analyzer PA-1000 preoperatively and intermittently postoperatively. RESULTS: In patients who underwent A-E anastomosis, high-tone voice pitch decreased significantly postoperatively (673.9-471.5 Hz, p = 0.047), with restoration achieved within 5 months. The mean voice pitch in female patients who underwent A-E anastomosis, EBSLN resection, and controls were 580.4, 522.8, and 682.0 Hz, respectively, indicating a significant decrease in EBSLN resection patients than controls (p = 0.002). The (mean - 1SD) of high-tone voice pitch in female controls was 497 Hz; exceeding this may indicate recovery to a high-tone voice. Overall, 73% (8/11) of A-E anastomosis patients exceeded this value, which was marginally larger than the 43% (6/14) who underwent EBSLN resection. Data on male subjects are limited. There were no cases of adverse functional or cosmetic events. CONCLUSIONS: A-E anastomosis, a novel simple procedure, restored high-tone voice to some extent without any adverse events and thus warrants further investigation. LEVEL OF EVIDENCE: 3 Laryngoscope, 134:3868-3873, 2024.

Early Internal Branch of Superior Laryngeal Nerve Bifurcation Passes Through Double Thyroid Foramen.

Internal branch of superior laryngeal nerve (ibSLN) provides sensory innervation mostly to the supraglottic part of the larynx and thus prevents aspiration during ingestion. Normally, it is distributed to the larynx after piercing the thyrohyoid membrane above the superior laryngeal artery. Multiple anatomical variations in the course of ibSLN have been reported. An early ibSLN bifurcation and course through double thyroid foramen constitutes an interesting anatomical variation that may easily lead to an injury during procedures in the thyroid gland and the larynx. Knowledge of the anatomical variability is essential in order to prevent surgical complications that could potentially impact the patient's quality of life.

Variations of the external branch of the superior laryngeal nerve during its course and its importance in surgical approaches: an experimental cadaveric study.

INTRODUCTION: Injury of the external branch of the superior laryngeal nerve can cause a hoarse or weak voice due to the functional loss (dysergia) of the cricothyroid muscle. Defining the anatomical variations of the external branch of the superior laryngeal nerve and estimating the frequency of it, it makes crucial for surgical interventions. AIM: To reveal the topography of the external branch in the Anatolian population, to prevent injury of it during the surgical intervention in the anterior neck region. MATERIALS AND METHODS: Twenty-six bilateral hemilarynges (4 females, 22 males) were dissected. The morphometric and morphological features of the external branch were examined. The obtained results were compared statistically left and right. RESULTS: Landmarks such as the thyroid gland and laryngeal prominence were determined for the detection of the external branch. The variations of the course of the external branch and the points of piercing the cricothyroid muscle or inferior constrictor pharyngeal muscle were evaluated. DISCUSSION: Although safe approaches have been described for nerve protection during neck surgeries, it can expose injuries during preliminary surgery approaches as the nerve is thinner and more superficial than other branches of the vagus nerve. However, it can be detected more easily and safely during the surgical approach by knowing the defined anatomical landmarks and morphological variations of the external branch. CONCLUSION: The anatomical variations described can be a safe and important guide in surgical approaches to be applied in the anterior neck region.

Variations in the course of the externalbranch of the superior laryngeal nerveand their importance in surgicalprocedures: an experimental cadaveric study.

<br><b>Introduction:</b> Injury of the external branch of the superior laryngeal nerve can cause a hoarse or weak voice due to the functional loss (dysergia) of the cricothyroid muscle. Defining the anatomical variations of the external branch of the superior laryngeal nerve and estimating their frequency are crucial for surgical interventions.</br> <br><b>Aim:</b> To reveal the topography of the external branch in the Anatolian population, to prevent injury of it during the surgical intervention in the anterior neck region.</br> <br><b>Material and methods:</b> 26 bilateral hemilarynges (4 females, 22 males) were dissected. The morphometric and morphological features of the external branch were examined. The obtained results were compared statistically, left and right.</br> <br><b>Results:</b> Landmarks such as the thyroid gland and laryngeal prominence were determined for the detection of the external branch. The variations of the course of the external branch and the points of piercing the cricothyroid muscle or inferior pharyngeal constrictor muscle were evaluated.</br> <br><b>Discussion:</b> Although safe approaches have been described for nerve protection during neck surgeries, injuries may occur during preliminary surgery as the mentioned nerve is thinner and more superficial than other branches of the vagus nerve. However, it can be detected more easily and safely by knowing the defined anatomical landmarks and morphological variations of the external branch.</br> <br><b>Conclusion:</b> The anatomical variations described can be a safe and important guide in surgeries of the anterior neck region.</br>.