Recurrent Nerve Research Articles

Influence of Raoul Husson’s neurochronaxic theory for the development of research on the physiological mechanisms of voice production in the Soviet Union (1950–1970s)

The influence of the neurochronaxic theory of phonation of the French physiologist Raoul Husson (1901–1967) on the development of research on voice formation in the Soviet Union, mainly in the 1950–1970s, is discussed. Husson contrasted the neurochronaxic theory with the traditional myoelastic theory of voice formation. The myoelastic theory considers the vocal folds as a self-oscillatory system. Vibrations are caused by the energy of the air flow. According to Husson’s concept, vibrations of the vocal cords do not depend on subglottic pressure. The frequency of vibration of the vocal cords corresponds to the frequency of impulses arriving along the recurrent nerve. To explain the high frequency of vibration of the vocal cords, Husson used Wever’s “Volley Principle”. According to this principle, the activity of each subsequent nerve fiber occurs during the refractory phase of the previous fiber. The responses of all nerve fibers are summed up into a common high-frequency oscillation. In 1950–1970s, Soviet physiologists took an active part in testing the new concept proposed by Husson. They came to the conclusion that both mechanisms, myoelastic and neurochronaxic, are involved in the functioning of the vocal apparatus. But the recurrent nerve does not directly control the vibrations of the vocal cords, but indirectly. Žhinkin called this control system the “code principle,” when a command is sent to the vocal cords to change their physical characteristics, changing the properties of the self-oscillating system.

Dissection of the lymph nodes along the recurrent laryngeal nerve in robotic esophagectomy

Lymph node (LN) metastasis serves as a pivotal prognostic determinant in esophageal cancer, particularly in cases of squamous cell carcinoma (SqCC). The involvement of LN metastasis frequently extends to the LNs along the recurrent laryngeal nerve (RLN). Radical dissection of these nodes is imperative for precise staging and the prevention of loco-regional recurrence. Historically, the emphasis on RLN node dissection has been evident in numerous literature, establishing it as a mandatory procedure in different countries. Nevertheless, the risk of RLN palsy following such dissection is a substantial concern, given its association with significant postoperative complications and long-term implications for quality of life. Recent literature has highlighted RLN node dissection in robotic surgery, demonstrating favorable outcomes in comparison to alternative surgical modalities. This review paper aims to comprehensively assess prior publications on this subject, elucidating the outcomes and implications of RLN node dissection in robotic esophagectomy (RE).

Recurrent Ulnar Nerve Schwannoma in the Cubital Tunnel Elbow: A Rare Presentation and Surgical Management

Recurrent Ulnar Nerve Schwannoma in the Cubital Tunnel Elbow: A Rare Presentation and Surgical Management

Recurrent laryngeal nerve lymph node dissection with subcomplete sealing using advanced bipolar energy device in minimally invasive esophagectomy.

Recurrent laryngeal nerve (RLN) palsy is a complication that must be avoided during esophagectomy. While RLN injury is thought to be caused by thermal spread from electric devices, electric devices are useful to avoid bleeding. When dissecting lymph nodes around RLNs, to seal small vessels, we use subcomplete technique with advanced bipolar. We describe our surgical technique, termed the subcomplete sealing technique, in RLN lymph node dissection. The first step is to perform blunt dissection with forceps on both sides of the esophageal branch near the right RLN. A distance of at least 2 mm from the RLN was preferred. Sealing with advanced bipolar often causes tissue shrinkage, pulling the RLN near the device. To prevent this, sealing should be stopped before reaching completion. Although the sealing was not complete, it was sufficient to seal the small vessels. After subcomplete sealing, the sealed tissues were dissected using laparoscopic scissors. The lymph nodes around left RLN are dissected in the same manner. A total of 76 patients received esophagectomy with the subcomplete technique. Grade IIIa RLN palsy occurred in three cases (3.95%). Over Grade IIIb RLN palsies did not occur. This subcomplete sealing technique can assist surgeons in performing RLN lymph node dissection without bleeding and increasing the rate of RLN palsy.

Managing esophageal squamous cell carcinoma after cervical radiotherapy for a head and neck cancer: esophagectomy remains a viable option.

Managing esophageal squamous cell carcinoma (ESCC) in patients with a history of cervical radiotherapy for a head and neck cancer (HNC) often requires a careful evaluation of esophagectomy due to concerns regarding complications and prognosis. This study evaluates the periesophagectomy and oncological outcomes of such patients. Patients diagnosed with ESCC between January 2010 and August 2023 and who had undergone esophagectomy with cervical anastomosis were retrospectively reviewed. Patients were categorized into two groups based on the presence (group 1) or absence (group 2) of a history of radiotherapy for as HNC. After 1: 2 propensity score matching, the perioperative and oncological outcomes, including overall survival (OS) and recurrence-free survival (RFS), were evaluated. A total of 481 patients, 32 in group 1 and 449 in group 2, were included. After matching, group 1 patients and 64 patients in the group 2 were analyzed. All the patients in group 1 were males, and their mean age was 56years. The median radiation dose was 69Gy. The rates of anastomosis leakage, pneumonia, respiratory failure, and reoperation were comparable between the two groups. However, vocal cord palsy occurred more frequently in group 1, particularly in those with recurrent laryngeal nerve lymph node dissection (37.5%). The 3-year OS (69.6% vs. 75.2%; p = 0.26) and RFS (50.8% vs. 55.9%; p = 0.63) were similar between groups 1 and 2. In conclusion, perioperative and oncological outcomes were comparable between ESCC patients with and without prior HNC radiotherapy, supporting esophagectomy as a feasible option.

The anatomical relationship between recurrent laryngeal nerve and inferior thyroid artery in thyroidectomy patients.

Objective: To identify the anatomical relationship of recurrent laryngeal nerve with inferior thyroid artery. Study Design: Prospective Clinical study. Setting: Department of Surgery, Kishwar Fazal Teaching Hospital. Period: July 2019 to February 2023. Methods: Total 64 patients underwent subtotal thyroidectomies for proven benign goiters were enrolled. Results: Out of these 64 patients, 8 were male and 56 were female, male to female ratio 1:7 with median age 34 years. In 64 patients, 128 dissections were performed and in all patients (RLN) and its relation with Inferior Thyroid Artery (ITA) was identified. On right side of neck in 63 (98.43%) patients out of 64 (100%) patients RLN found deeper to ITA and in one (1.56%) patient it was found superficial to ITA. On left side of neck in 61 (95.31%) patients out of 64(100%) patients it was deeper to ITA and in 3 (4.68%) patients the nerve was superficial to ITA. Identification of RLN was difficult in 16 (12.5%) dissections and the reason was adhesions and huge multinodular goiter. Conclusion: During thyroid surgery, the connection between RLN and ITA is significant to surgeons. When it comes to RLN security, visible anatomical identification is still the gold standard.

Frequency and outcomes of parathyroid preservation in total thyroidectomy.

Objective: To determine the frequency and its outcome of parathyroid preservation in total thyroidectomy. Study Design: Case Series study. Setting: Department of Otorhinolaryngology, HMC, MTI, Peshawar. Period: 23rd June 2022 to 23rd Dec 2022. Methods: A total of 246 patients who underwent thyroidectomy were included in the study and followed up to determine the preservation of parathyroid gland, hypocalcaemia and recurrent laryngeal nerve injury. Results: The mean age of the sample was 37.7 + 12.3 years. There were 52.8% male patients and 47.2% female patients. 28.9% of patients had thyroid nodule and subtotal thyroidectomy was the most performed procedure Parathyroid gland preservation was recorded in 72%. On follow up, hypocalcemia was recorded in 16.3% and recurrent laryngeal nerve injury in 20.3%. Conclusion: Hypocalcemia and RLNI are significantly common after thyroidectomy. Hypocalcemia was significantly high in patients with low non preserved parathyroid gland. More research on high sample size and addressing other effect modifiers are recommended with intervention to preserve parathyroid gland.

Robotic-assisted lymph node dissection along the left recurrent laryngeal nerve, ergonomically free two-handed dissection, connective tissue around the recurrent laryngeal nerve.

Robotic-assisted lymph node dissection along the left recurrent laryngeal nerve, ergonomically free two-handed dissection, connective tissue around the recurrent laryngeal nerve.

Tissue-Engineered Implant for Hemilaryngectomy Reconstruction with Recurrent Laryngeal Nerve Injury.

Laryngeal cancer resections often require excision of portions of the larynx along with sacrifice of the ipsilateral recurrent laryngeal nerve (RLN). In such cases, there are no reconstructive options that reliably restore laryngeal function, rendering patients with severe functional impairment. To address this unmet clinical need, we extend our evaluation of a 3-implant mucosal, muscle, cartilage reconstruction approach aimed at promoting functional laryngeal restoration in a porcine hemilaryngectomy model with ipsilateral RLN transection. Six Yucatan mini-pigs underwent full-thickness hemilaryngectomies with RLN transection followed by transmural reconstruction using fabricated collagen polymeric mucosal, muscle, and cartilage replacements. To determine the effect of adding therapeutic cell populations, subsets of animals received collagen muscle implants containing motor-endplate-expressing muscle progenitor cells (MEEs) and/or collagen cartilage implants containing adipose stem cell (ASC)-derived chondrocyte-like cells. Acoustic vocalization and laryngeal electromyography (L-EMG) provided functional assessments and histopathological analysis with immunostaining was used to characterize the tissue response. Five of six animals survived the 4-week postoperative period with weight gain, airway maintenance, and audible phonation. No tracheostomy or feeding tube was required. Gross and histological assessments of all animals revealed implant integration and regenerative remodeling of airway mucosa epithelium, muscle, and cartilage in the absence of a material-mediated foreign body reaction or biodegradation. Early voice and L-EMG data were suggestive of positive functional outcomes. Laryngeal reconstruction with collagen polymeric mucosa, muscle, and cartilage replacements may provide effective restoration of function after hemilaryngectomy with RLN transection. Future preclinical studies should focus on long-term functional outcomes. NA Laryngoscope, 134:4604-4613, 2024.

Quantitative Analysis of Genicular Nerve Block Spread and Variability: Anatomical Correlations and Clinical Implications

BackgroundDespite advancements in anaesthesiology and regional anaesthesia, the three-dimensional spread of local anaesthetics is still poorly understood. This study investigates the pericapsular spread of radiopaque contrast after ultrasound-guided genicular nerve block in cadaveric knees using CT reconstruction. The aim is to assess the reproducibility, accuracy, and variability of this technique in order to improve safety and effectiveness. MethodsWe used a four-stage methodology that involved performing genicular nerve block on cadaveric knees, acquiring data using high-resolution ultrasound and helical CT imaging, performing segmentation and surface reconstruction of the CT images, and analysing the data quantitively to determine the spread of the infiltrate in each genicular nerve region. Coefficients of variation were calculated to estimate the spread and reproducibility of each genicular nerve block. ResultsOur results revealed significant variability in spread in all genicular nerve blocks, particularly around the recurrent genicular nerve. Despite this variability, the spread—particularly along the medial-lateral and anterior-posterior axes—showed moderate consistency. Furthermore, the regions covered by 80% of the spread closely matched the pericapsular distribution of the genicular nerves of the knee. ConclusionsNotable variability in spread was observed in genicular nerve blocks, particularly around the recurrent genicular nerve. However, the spread showed moderate consistency and aligns closely with the pericapsular nerve distribution of the knee. Future studies should combine quantitative analysis with anatomical dissection to further investigate the involvement of the deep peroneal motor branch.

Coordination of Pharyngeal and Esophageal Phases of Swallowing.

Although swallowing has been reviewed extensively, the coordination of the phases of swallowing have not. The phases are controlled by the brainstem, but peripheral factors help coordinate the phases. The occurrence, magnitude, and duration of esophageal phase depends upon peripheral feedback activated by the bolus. The esophageal phase does not occur without peripheral feedback from the esophagus. This feedback is mediated by esophageal slowly-adapting mucosal tension receptors through the recurrent and superior laryngeal nerves. A similar reflex mediated by the same peripheral pathway is the activation of swallowing by stimulation of the cervical esophagus. This reflex occurs primarily in human infants and animals, and this reflex may be important for protecting against aspiration after esophago-pharyngeal reflux. Not only are there inter-phase excitatory processes, but also inhibitory processes. A significant inhibitory process is deglutitive inhibition. When one swallows faster than peristalsis ends, peristalsis is inhibited by the new pharyngeal phase. This process prevents the ongoing esophageal peristaltic wave from blocking the bolus being pushed into the esophagus by the new wave. The esophageal phase returns during the last swallow of the sequence. This process is probably mediated by mucosal tension receptors through the superior laryngeal nerves. A similar reflex exists, the pharyngo-esophageal inhibitory reflex, but studies indicate that it is controlled by a different neural pathway. The pharyngo-esophageal inhibitory reflex is mediated by mucosal tension receptors through the glossopharyngeal nerve. In summary, there are significant peripheral processes that contribute to swallowing, whereby one phase of swallowing significantly affects the other.

Influence of Anesthesiology Protocol on the Quality of Intraoperative Nerve Monitoring During Thyroid Surgery, One-Year Single Center Experience.

Anesthesia plays a very important role in the successful management of intraoperative neuromonitoring (IONM). The aim of our study was to investigate the impact of anesthesia induction and maintenance on the quality of signals during surgeries on the thyroid and parathyroid glands using neuromonitoring. The study included 72 patients who underwent surgery with IONM for one year. All the patients were intubated using a Glidescope videolaryngoscope with a hyperangulated blade. Two different approaches were used to facilitate intubation: succinylcholine-1 mg/kg and rocuronium bromide-0.3 mg/kg. For anesthesia maintenance, total intravenous anesthesia (TIVA) or combined anesthesia was used. Patients' body movements during operations, as well as electromyography signals from the vagus and recurrent laryngeal nerves before resection, were recorded as V1 and R1. Intraoperative unwanted movements were recorded in 25% of patients. Undesired movements were more frequently recorded in the TIVA group compared to the combined anesthesia group (p < 0.001) as well as in patients who received succinylcholine compared to patients who received rocuronium bromide (p = 0.028). Type of anesthesia maintenance as well as type of muscle relaxant did not affect the quality of recorded nerve signals. (p = 0.169 and p = 0.894, respectively). The type of muscle relaxant used significantly affects the occurrence of undesirable movements during thyroid surgery with IONM, while the type of anesthesia maintenance did not influence either the quality of the obtained signal or the occurrence of undesirable movements.

Laparoscopic and thoracoscopic whole-stomach esophagectomy with preoperative pyloric balloon dilatation for esophageal cancer: a prospective multicenter case-series outcome

IntroductionTo mitigate gastroparesis as well as other post-operative complications, we undertook a prospective multicenter study to assess the feasibility, safety, and efficacy in the short-term outcomes of laparoscopic and thoracoscopic whole stomach esophagectomy with preoperative pyloric balloon dilatation.MethodsA prospective descriptive study on 37 patients with laparoscopic and thoracoscopic whole stomach esophagectomy with preoperative pyloric balloon dilatation from January 2019 to March 2023. The perioperative indications, clinical data, intra-operative index, pathological postoperative specimens, postoperative complications, and follow-up results were retrospectively evaluated.ResultsIn our study, all patients were male, with dysphagia as the predominant symptom (45.9%). Esophageal cancer incidence was similar between middle and lower thirds. Nodules were the primary finding on esophagoscopy (48.6%). Preoperative pyloric dilation averaged 31.2 min without complications. Surgical duration ranged from 225 to 400 min (mean 305). Gastric tube fluid volume averaged 148.9 ± 110.66 ml per day. Among 34 post-operative cases underwent gastric transit scans, most had non-dilated stomachs with efficient pyloric drug circulation. Three cases required prolonged ventilation, precluding pyloric circulation scans. Four patients developed chylous fistula, one requiring chest tube embolization. Recurrent laryngeal nerve damage occurred in 10.8% of cases.ConclusionAfter evaluating esophageal cancer patients undergoing laparoscopic whole-stomach esophagectomy with preoperative pyloric balloon dilatation, it was found that this procedure is safe, effective, and significantly reduces postoperative gastroparesis and related complications.

Thyroid Radiofrequency Ablation-Thermal Effects on Recurrent Laryngeal Nerve Using Continuous Intraoperative Neuromonitoring Animal Model.

When performing radiofrequency ablation for thyroid nodules, it is essential to avoid thermal injury to the recurrent laryngeal nerve. This porcine animal model study used continuous intraoperative neuromonitoring to investigate the thermal safety parameters of thyroid radiofrequency ablation. Porcine animal study. University animal laboratory. Twelve piglets were tested at different radiofrequency power levels, and the real-time electromyography signal changes were recorded under continuous intraoperative neuromonitoring. The spread heat study (8 piglets) included spontaneous recovery tests and cold water irrigation tests to investigate the safety distance from the recurrent laryngeal nerve to the active tip during 5-second activation with standard stimulation patterns. The residual heat study (4 piglets) investigated the safety cooling durations by touching the recurrent laryngeal nerve with the tip after a 5-second activation. In the spread heat study, substantial signal attenuation events were observed at an spread heat distance of 2, 3, 5, and 5 mm when the power was set as 10, 20, 30, and 50 W, respectively. No signal recovery could be observed in 20 minutes with or without cold water irrigation in the injured recurrent laryngeal nerve area. The residual heat study shows the residual thermal effect of the tip is minimal, and no substantial signal attenuation event was observed at all experiments. This innovative study established the thermal safety parameters for radiofrequency ablation in a porcine model at various power levels, which can potentially assist operators in delineating a precise ablation field and providing effective thyroid ablation treatment safely.

Modern Possibilities for Reconstruction of Nerves of the Head and Neck

The main etiological factors of nerve damage to the head and neck include injuries, oncological diseases, iatrogenic injuries during surgical interventions. An important task of treatment is to restore the lost function of the nervous head and neck, the functions of which certainly determine the quality of life of the patient. The article presents modern methods of nerve reconstruction of the head and neck. The methods of reconstructive surgery of the facial, trigeminal, inferior alveolar, lingual, recurrent laryngeal nerves are described. This article also describes the types of rehabilitation after reconstructive operations on the nerves of the head and neck using pharmacological and non-pharmacological treatment methods such as botulinum therapy, neuromuscular retraining, taping, post-isometric relaxation, acupuncture, phonophoresis, gymnastics.

Patterns of the Relationship Between Recurrent Laryngeal Nerve and Inferior Thyroid Artery in the Setting of Total Thyroidectomy: A Prospective Single-Surgeon Study

Patterns of the Relationship Between Recurrent Laryngeal Nerve and Inferior Thyroid Artery in the Setting of Total Thyroidectomy: A Prospective Single-Surgeon Study

Peak expiratory flow predicts the occurrence of postoperative pneumonia after esophagectomy for esophageal cancer.

Expiratory flow is an important factor in the achievement of airway clearance that is required to prevent postoperative pneumonia (POP). Although peak expiratory flow (PEF) has been shown to predict the occurrence of POP in lung cancer patients after lobectomy, its predictive power in relation to esophagectomy for esophageal cancer remains unknown. This study assesses PEF as a predictor of POP in patients with esophageal cancer undergoing radical esophagectomy. We conducted a single-center, retrospective cohort study of patients who underwent radical esophagectomy with gastric tube reconstruction at our institution between January 2007 and December 2022. Preoperative pulmonary functions, including PEF, were assessed before surgery. Additionally, POP was diagnosed as a Clavien-Dindo classification of Grade II or higher. Survival and pneumonia incidence were compared using the Kaplan-Meier method. Logistic regression analysis was used to examine the relationship between these variables and POP. The study included 513 patients, of which 441 were men. POP occurred in 86 patients (16.7%). When all patients were stratified by %PEF into two groups, the group with %PEF lower that 80% had significantly poorer prognosis and higher incidence of pneumonia. Multivariable logistic regression analysis indicated that %PEF (OR: 0.986, 95%CI: 0.974-0.999, P = 0.030), along with age, BMI, preoperative treatment, and recurrent laryngeal nerve palsy were independent protective factors against POP. These results reveal that %PEF predicts the development of POP following esophagectomy for esophageal cancer.

A case report of an Adachi-Williams type CG plus H aortic arch anomaly and implications for the development of the cervicothoracic circulation.

It is unclear whether the development of the branches of the subclavian artery is dependent on the proximal part of this artery since great vessel formation is partially regulated by haemodynamic stress. For example, the vertebral artery that usually arises from the subclavian artery might be affected by anomalies in the aortic arch branches. This uncertainty is partly due to the limited reports of highly anomalous cases of proximal and distal branching morphologies. Here, we report an Adachi-Williams type CG plus H aortic arch case found during student dissection and discuss the development of the cervicothoracic circulation. Here, we report an aberrant right subclavian artery that arose from the aorta distal to the left subclavian artery, via a retroesophageal course, whereas the right and left common carotid arteries arose from a short common trunk from the aorta (the carotid trunk) (Adachi-Williams type H). In addition, the left vertebral artery arose directly from the aortic arch between the carotid trunk and the left subclavian artery (Adachi-Williams type CG). Anomalies in the branching arteries from this aberrant right subclavian artery (the right vertebral artery, internal thoracic artery, thyrocervical trunk, costocervical trunk and thoracoacromial artery) were unidentifiable. The right vagus nerve directly innervates the laryngeal muscles without forming the recurrent nerve. The development of an aberrant right subclavian artery might affect haemodynamic stress in both the proximal and distal regions of the anterior limb region. The distal branching morphology, however, was normal, suggesting an independence of proximal and distal vasculature development. Since the concomitance of Adachi-Williams-type CG and H is rare, rather than sequentially develop, the distal arteries develop in a fine-tuned manner to adapt to anomalies in the proximal arteries.

Robot-assisted minimally invasive esophagectomy for esophageal cancer in the left lateral decubitus position.

The use of robot-assisted minimally invasive esophagectomy (RAMIE) in the prone position for esophageal cancer has been currently increasing worldwide. In future, as surgical-assisted robots become more widespread, it is estimated that only two methods of transthoracic approach will remain: RAMIE and open thoracotomy for thoracic esophageal cancer. RAMIE in the left lateral decubitus position (RAMIE-LLDP) has the same field of view as open thoracotomy, is safe in emergency situations, and provides education on open thoracotomy. Between September 2020 and April 2024, RAMIE-LLDP was performed in 64 consecutive patients with esophageal cancer. RAMIE-LLDP was performed with the operating table rotated and tilted 45° to the ventral side under artificial pneumothorax. The hand-control setting of the surgical-assist robot system was reversed left to right when the Patient Cart was rolled from the same direction as the RAMIE in the prone position. The mean total surgery and console times during the thoracic procedure were 254-min overall and 225min in the last 24 cases and 195-min overall and 178-min in the last 24 cases, respectively. The mean amount of blood loss was 203.4g overall and 28.3g in the last 24 cases. Postoperative recurrent laryngeal nerve palsy with Clavien-Dindo classification (CD) was ≥ 2 in six patients (9.4%). Postoperative pneumonia with CD ≥ 2 was observed in 11 patients (17.2%). Conversion to open thoracotomy was observed in three patients (4.7%). In all three patients, an immediate conversion to thoracotomy without patients' position change was actually possible and no serious complications were noted. No mortality occurred within 30days postoperatively. RAMIE-LLDP which facilitates emergency thoracotomy has perioperative results comparable to those of conventional thoracoscopic esophagectomy and is educational for open surgery. RAMIE-LLDP is the safest and most optimal surgery for esophageal cancer.

A prospective observational study on the anatomical variations of recurrent laryngeal nerve and its application in the prevention of injury during thyroid surgery in a tertiary care centre

BackgroundThyroid gland is the largest and most vascular structure among the endocrine glands. The recurrent laryngeal nerve and the superior laryngeal nerve are closely related to the thyroid gland; these nerves control voice and are vital in breathing. Anatomical preservation of the recurrent laryngeal nerve (RLN) is the gold standard in thyroid surgery. Visual identification of RLN has decreased the rates of permanent RLN palsy during thyroid and parathyroid operations. Prior knowledge about the branching patterns will help in predicting and preventing injury to the nerve during thyroid surgery.Aim and objectivesThe aim of the study is to observe the terminal branching pattern of recurrent laryngeal nerve before its entry into the larynx.MethodsAn observational study with 50 participants who fulfilled the inclusion and exclusion criteria were enrolled in the study. After a complete evaluation and pre-anaesthetic checkup, the patients were operated and intraoperative findings of RLN branching were recorded and compared for the study.ResultsIn our study, out of the 50 patients who underwent thyroid surgery during the course of the study, right-sided RLN branching was demonstrated in 25 patients (21 right hemithyroidectomy and 4 total thyroidectomy). Ten patients had RLN bifurcation, 7 had trifurcation, 5 had numerous branches, and 3 with no branching pattern were noted. Similarly, out of 29 patients (25 left hemithyroidectomy and 4 total thyroidectomy) in whom left-sided RLN branching was studied, bifurcation was seen in 10 patients, trifurcation in 12 patients, and multiple branching was observed in 7.ConclusionThe anatomical variations seen in RLN may increase the risk of vocal cord palsy due to its injury. Anatomical variations are categorized according to the original direction of the RLN and the number of terminal branches in the larynx. This classification aids in the identification and preservation of its branches, hence facilitating a safer thyroidectomy.