Superior Laryngeal Nerve Research Articles

Comprehensive review of laryngeal nerve

The laryngeal nerve plays a crucial role in vital functions of the larynx, such as breathing, phonation, and airway protection. This review explores its intricate origination, extracranial pathways, anatomical variations, and functions. Emerging from the vagus nerve, it descends through the jugular foramen, exhibiting distinct pathways on each side of the body. Understanding these pathways is vital in surgery to prevent complications. Anatomical variations, including the non-recurrent laryngeal nerve and extralaryngeal branching, pose challenges during thyroid surgery. Surgeons must be vigilant, as failure to recognize these variations can lead to nerve injuries. Meticulous preoperative evaluation and surgical expertise are essential. The superior laryngeal nerve triggers protective reflexes like the cough reflex, safeguarding the respiratory tract. The recurrent laryngeal nerve controls crucial laryngeal muscles for phonation and respiration. Understanding these functions is paramount, especially for surgeons, ensuring optimal patient outcomes. In conclusion, this review underscores the laryngeal nerve's complexity and the need for in-depth knowledge, particularly in surgery. Ongoing research and medical advancements are crucial for refining techniques and enhancing patient care. Acknowledging these complexities empowers medical surgeons contributing to safer and more effective surgeries.

Routine use or selective use of the Intraoperative neuromonitoring during thyroidectomy

Intraoperative neuromonitoring (IONM) has become a widely utilized technique in thyroid surgery, While the routine identification of the recurrent laryngeal nerve has improved the safety of thyroidectomy, recurrent laryngeal nerve palsy remains an important complication. Some studies have shown promising results with IONM, demonstrating a lower incidence of nerve palsy compared to traditional visualization. However, the overall impact of IONM remains debated, as not all studies confirm its efficacy, especially in redo thyroid surgery. The use of IONM offers benefits in identifying and preserving the external branch of the superior laryngeal nerve, especially in cases of multinodular goiters. The decision to employ IONM should be individualized based on the surgeon's experience and the patient's clinical situation. However, its routine use is not universally supported, and its advantages may be more pronounced in specific high-risk patients and low volume surgeons.

갑상선 수술중 신경모니터링의 최근 연구

Thyroid surgery is associated with a risk of injury to the recurrent laryngeal nerve(RLN), the external branch of the superior laryngeal nerve(EBSLN), and voice changes. Intraoperative neuromonitoring(IONM) has already gained universal reliability to help in nerve identification, safe nerve dissection, and prediction of postoperative vocal cord function. IONM techniques have evolved over the past decade into intermittent IONM(I-IONM) and continuous IONM(C-IONM) modes of application. Research in the field of IONM continues, exploring new techniques and approaches to further enhance the safety and efficacy of thyroid surgery. In this article, the role of IONM and its recent studies will be reviewed.

Management of Bilateral Vocal Fold Paralysis, Injury of External Branch of Superior Laryngeal Nerve after Thyroid Surgery

Management of Bilateral Vocal Fold Paralysis, Injury of External Branch of Superior Laryngeal Nerve after Thyroid Surgery

Outcomes and predictors of complications of thyroidectomy in a scarce resource setting: Retrospective cross-sectional study

BackgroundOutcomes and predictors of complications of thyroidectomy are diverse and have been extensively studied, but data from our country and other African countries with high disease burdens are limited. ObjectiveTo evaluate the outcomes and predictors of complications of thyroidectomy among operated patients. MethodSingle institution retrospective cross-sectional study was conducted by reviewing charts from 365 patients who had undergone thyroidectomy on an elective basis between March 2018–February 2022. All patients who were admitted and underwent thyroidectomy were included in this study. Bivariate and multivariate logistic regressions were used to identify risk factors. P-value <0.05 was considered statistically significant. ResultOverall, post-thyroidectomy complications occurred in 17 % of the cases. The two most common complications were hypocalcemia and voice change; the latter being due to injury of either external branch of superior laryngeal nerve or recurrent laryngeal nerve with an incidence of 4.9 % and 2.5 % respectively. Thyroidectomy performed by surgical residents and having total thyroidectomy were significantly associated with overall complications of thyroidectomy. Total thyroidectomy was found to be a risk factor for postoperative hypocalcemia (AOR = 12.24 (95%CI: 4.53, 19.65); P = 0.02). Younger age of the patient (AOR =0.3(95%CI, 0.12,0.51)) and prolonged duration of presentation (AOR = 2.53(95%CI, 1.17,7.76)) were detected predictors of voice change due to injury of either external branch of superior laryngeal nerve or recurrent laryngeal nerve. ConclusionThe rate of thyroidectomy complications is relatively similar to other studies. In this study demographic and clinical factors associated with increased risk of complications after thyroid surgery were identified. This information will be useful for educating patients about the risks of thyroid surgery.

Modulation of the swallowing reflex by stimulation of the gigantocellular reticular nucleus in the rat

ObjectivesThe gigantocellular reticular nucleus (Gi) projects to the nuclues of the solitary tract nucleus (NTS) and the lateral reticular formation (LRF) above the nucleus ambiguus. The swallowing central pattern generator comprises the NTS and the LRF. The present study examined whether stimulation of the Gi affects the swallowing reflex. MethodsExperiments were performed on urethane-anesthetized rats. The swallowing reflex was evoked by repetitive electrical stimulation of the superior laryngeal nerve and responses were recorded from the mylohyoid muscle on an electromyogram. The Gi was stimulated electrically. In addition, glutamate was injected into the Gi. The Friedman's test, followed by the Wilcoxon signed-rank test with Bonferroni correction, were used to assess the effects of electrical stimulation of the Gi. The Wilcoxon signed-rank test was used to assess the effects of glutamate injection into the Gi. Differences were considered significant at the P < 0.05 level. ResultsThe number of swallows was significantly increased or decreased by electrical stimulation of the Gi or after injection of glutamate into the Gi. In both electrical stimulation of the Gi and injection of glutamate into the Gi, the onset latency of the first swallow was prolonged when the number of swallows was decreased but showed no change when the number of swallows was increased. ConclusionsThe present results suggest that the Gi is involved in the control of swallowing.

Hybrid Surgery for Revascularization of Chronic Occlusion of Internal Carotid Artery.

The aim of this study was to conclude the safety and effectiveness of hybrid surgery for revascularization of chronic occlusion of internal carotid artery (COICA). A total of 56 COCIA patients underwent hybrid surgery (carotid endarterectomy+carotid artery stenting) from September 2017 to September 2021 in our department. The clinical material and radiology data (preoperation and postoperation) were retrospectively analyzed to conclude the safety and effectiveness of hybrid surgery for revascularization of COICA. All 56 patients underwent hybrid surgery got revascularization successfully (with a successful rate of 100%) and improved intracranial blood flow. The computed tomography perfusion results indicate that the postoperative cerebral blood flow perfusion of the patient is significantly improved compared with before surgery. In 1 patient, postoperative brain magnetic resonance imaging within 24 hours showed spotted fresh infarction with head magnetic resonance imaging, without any clinical symptoms; 3 patients developing symptoms of ipsilateral neural-functional defect (hypoglossal nerve, superior laryngeal nerve, and mandibular branch of facial nerve, respectively), 2 weeks later the symptoms were disappeared. Imaging study at 3 and 6 months during the follow-up showed no abnormalities. Hybrid surgery is safe and effective for revascularization of COICA.

Modified anterior approach versus traditional posterior approach for ultrasound-guided superior laryngeal nerve block in awake endotracheal intubation: a randomized non-inferiority clinical trial

Study objective This study was undertaken to compare the effect of the modified ultrasound-guided anterior superior laryngeal nerve block (SLNB) with the traditional ultrasound-guided posterior SLNB in providing intubation conditions during awake tracheal intubation (ATI) in patients without difficult airway. Design Randomized, assessor-blind. Registration number: ChiCTR2200058086. Setting West China Hospital of Sichuan University, Chengdu, China. Patients 104 patients aged 18–65 years, of American Society of Anesthesiologists status I-III, posted for elective general surgery with general endotracheal anesthesia. Interventions The patients were randomized into two groups (modified group, n = 52; traditional group, n = 52). Modified anterior SLNB or traditional posterior SLNB was performed under ultrasound guidance. Measurements The primary outcome was the proportion of acceptable intubation condition (AIC), which was analyzed in both per-protocol (PP) and intention-to-treat (ITT) populations. The prespecified non-inferiority margin was −4.8%. Secondary outcomes included intubation success rate on the first attempt, hemodynamic parameters during ATI, time taken for airway anesthesia and intubation, recall of intubation, patient perception of comfort, and incidence and severity of postoperative complications. Main results In the PP population, the proportion of AIC in the modified group was 49/49 (100%) and that in the traditional group was 49/49 (100%), absolute difference 0, lower limit of 1-sided 95% CI, −0.3%. In the ITT population, the primary outcomes in the modified and traditional group were 52/52 (100%) and 51/52 (98.1%), respectively, with an absolute difference of 1.9% and a lower limit of 1-sided 95% CI of −1.2%. The non-inferiority of modified ultrasound-guided anterior SLNB was confirmed in both populations. Conclusions Among adults without difficult airways during videolaryngoscope-assisted ATI, the modified ultrasound-guided anterior SLNB, compared to the traditional posterior approach, showed a statistically non-inferior effect in terms of providing AIC.

The larynx in 3 dimensions: A digital anatomical model derived from radiographic imaging, refined with peer-reviewed literature, and optimized with medical illustration

ObjectivesDevelopment of an anatomically accurate three-dimensional (3D) digital model of the human larynx derived from published literature and radiographic imaging. Materials and MethodsThe laryngeal framework was segmented from a computed tomography (CT) angiogram of a healthy 29-year-old female. Data derived from published anatomical studies were compiled to provide additional anatomical detail to each structure. Anatomical details beyond the resolution of the imaging study or which could not be elucidated from the study were refined according to descriptions in the anatomic literature. The 3D model was refined by the medical illustrator, and its mesh was reformatted to optimize online viewing and manipulation. ResultsDue to the small size of the laryngeal muscles, there was no attempt to segment these muscles using radiographic imaging. All intrinsic laryngeal muscles were generated de novo, as were the superior laryngeal nerve and recurrent laryngeal nerve. CT imaging was utilized to generate meshes of the hyoid bone, epiglottis, thyroid cartilage, cricoid cartilage, and thyrohyoid membrane. Additionally, the airway space was segmented to provide size and spatial location to the vallecula, false vocal folds, true vocal folds, piriform sinus, subglottis, and a scaffold for the mucosa. These meshes were processed to limit radiographic artifact and serve as a foundation for the construction of the remainder of the laryngeal anatomy. The model was uploaded to a 3D repository, which can be accessed here (https://shorturl.at/nJPYZ). ConclusionThe larynx is a highly specialized organ essential for speech, swallowing, and airway protection. This study describes a digital 3D model of the larynx, created by combining radiographic imaging with critical review of anatomic literature. Utilizing the expertise of neuroradiology, laryngeal surgery, and medical illustration, we highlight surgically-relevant anatomic relationships and important aspects to consider during laryngeal surgery.

Effect of superior laryngeal nerve block in alleviating sore throat after application of i-gel supraglottic airway: a randomized controlled trial

BackgroundPostoperative sore throat (POST) is a common complaint after supraglottic airway device (SAD) application. Internal branch of the superior laryngeal nerve (iSLN) block has the potential to alleviate POST. The aim of this trial was to explore the effect of iSLN block in alleviating sore throat, as well as to identify the potential risk factors for POST after SAD insertion.MethodsOne hundred thirty-four patients scheduled for elective gynecological surgery were randomized to either group T: tetracaine syrup (1%) for local lubrication on i-gel supraglottic device (n = 67) or group B: i-gel insertion with water based lubricant on it and followed by bilateral iSLN block (ropivacaine, 0.375%, 2 ml for each side) (n = 67). Under ultrasound guidance, iSLN was exposed below thyrohyoid membrane. The primary outcome was the intensity of sore throat at 6 h after surgery. In addition, POST score at 0.5 h and 24 h, the severity of postoperative swallowing discomfort, acoustic analysis and complications were measured.ResultsCompared with tetracaine syrup for local lubrication, iSLN block resulted in a reduced intensity of POST at 0.5 h (P = 0.044, OR = 1.99, 95%CI 1.02 to 3.88) and 6 h (P < 0.001, OR = 5.07, 95%CI 2.53 to 10.14) after surgery, as well as less severity of swallowing discomfort (P < 0.001, OR = 2.21, 95%CI 1.63 to 2.99) and cough (P = 0.039, OR = 1.97, 95%CI 1.04 to 3.73). The patients after iSLN block presented lower jitter and shimmer value in acoustic analysis at 6 h after surgery (P < 0.001).ConclusionsiSLN block was effective in alleviating POST, improving voice function, as well as reducing postoperative swallowing discomfort and coughing.Trial registrationChinese Clinical Trial Registry (ChiCTR2000037974) on 8th Sept 2020.

Neurophysiology of the Superior Laryngeal Nerve in an In Vivo Rat Model.

The superior laryngeal nerve (SLN) is fundamental in laryngeal sensation, cough reflex, and pitch control. SLN injury has substantial consequences including altered sensation, aspiration, and dysphonia. To date, in vivo measurement of the SLN remains elusive. The purpose of this study was to assess the feasibility of recording motor and sensory evoked potentials in a rat SLN model. Twenty-two rat hemi-laryngeal preparations (n = 11) were obtained from 4-month-old Sprague-Dawley rats and included in this study. Compound motor action potentials (CMAPs) and motor unit number estimation (MUNE) were calculated by stimulating the SLN at the point of medial extension near the carotid artery and by placing a recording electrode on the cricothyroid muscle. Sensory response was determined through stimulation of the SLN and laryngoscopic visualization of a laryngeal adductor reflex (LAR). SLN and cricothyroid muscle cross-sections were stained and histologic morphometrics were quantified. Laryngeal evoked potentials were successfully obtained in all trials. Mean CMAP latency and negative durations were 0.99 ± 0.57 ms and 1.49 ± 0.57 ms, respectively. The median MUNE was 2.06 (IQR 1.88, 3.51). LAR was induced with a mean intensity of 0.69 ± 0.20 mV. Mean axon count, myelin thickness, and g-ratio were 681 ± 192.2, 1.72 ± 0.26, and 0.45 ± 0.04, respectively. This study demonstrates the feasibility of recording evoked response potentials following SLN stimulation. We hypothesize that this work will provide a tractable animal model to study changes in laryngeal sensation and cricothyroid motor function with aging, neurodegenerative disease, aspiration, or nerve injury. NA Laryngoscope, 134:1778-1784, 2024.

The Application of Superior Laryngeal Nerve Block for Non-Cough Laryngeal Hypersensitivity.

To investigate the effect of superior laryngeal nerve (SLN) block in patients with non-cough complaints relating to laryngeal who have failed conventional medical therapy. Retrospective chart review of 46 patients who underwent SLN block for non-cough indications between July 2019 and March 2022 was performed. Demographics, comorbidities, and patient-reported outcomes were collected. The primary diagnoses for this group included: odynophagia, throat pain, cervicalgia, muscle tension dysphonia, globus sensation, hyoid bone syndrome, and Eagle syndrome. The cohort underwent an average of 1.24 bilateral injections (range 0-7) and 0.87 unilateral injections (range 0-4). About 35 of 46 patients reported an average of 51.0% improvement in their symptoms, with the treatment effect lasting 7.60 weeks on average. On subgroup analysis, the patients with spasmodic dysphonia, odynophagia, and hyoid bone syndrome had the best percent improvement on average (75%-77.5%). Patients with globus sensation had the lowest percent improvement on average in response to this therapy, reporting only about 25%. Five patients experienced a mild adverse reaction immediately following injection which resolved spontaneously. The use of in-office SLN block for non-cough disorders involving the larynx requires further study with larger sample sizes to better delineate the efficacy of these applications. 4 Laryngoscope, 134:1765-1768, 2024.

The Role of Bilateral Superior Laryngeal Nerve Block in Managing Refractory Chronic Cough.

The aim was to investigate the utilization and efficacy of bilateral superior laryngeal nerve block in patients with refractory chronic cough. A retrospective chart review of 164 patients with refractory chronic cough who underwent bilateral SLN block at a single institution between November 2018 and September 2022 was performed. Demographics, comorbidities, and patient-reported outcomes including pre- and postinjection Leicester Cough Questionnaire (LCQ) scores were collected and analyzed. The cohort underwent an average of 2.97 bilateral injections (range 1-22), containing either corticosteroid and local anesthetic or corticosteroid alone. Notably, 116 of 164 of patients reported an average of 67.3% reduction in their symptoms, with the treatment effect lasting 7.60 weeks on average. The average pre- and postinjection LCQ scores were 9.70 and 13.82, respectively. A lower LCQ score represents a greater impairment of health status due to cough, and the minimum important change is 1.3 points between questionnaires. The average improvement on LCQ following bilateral SLN block was 4.11 points for this cohort. The use of in-office bilateral SLN block is an effective treatment that can be used alone or in conjunction with oral medications for the treatment of refractory chronic cough. 4 Laryngoscope, 134:1773-1777, 2024.

Gasless Endoscopic Thyroidectomy via the Trans-Axillary Approach.

For patients with early, low-risk papillary thyroid carcinoma, an increasing number are opting for endoscopic thyroid surgery due to its ability to achieve favorable therapeutic outcomes while maintaining excellent cosmetic results. Among the available endoscopic procedures, the Gasless Endoscopic Thyroidectomy Trans-axillary Approach (GETTA) has gained popularity among surgeons. This is attributed to its straightforward cavity construction, spacious operating area, precise visual field exposure, and manageable learning curve. However, few studies have provided detailed descriptions of the specific surgical steps involved in GETTA. Drawing from a synthesis of existing literature and our own clinical expertise, we present a comprehensive outline of the GETTA procedure. This process can be categorized into five distinct stages: positioning and incision planning; establishment of surgical cavities; identification and protection of the recurrent laryngeal nerve, inferior parathyroid gland, and central neck dissection; localization and preservation of the superior laryngeal nerve, superior parathyroid gland, and dissection of the thyroid's superior pole; transection of the thyroid isthmus followed by en bloc resection of the thyroid gland and central neck lymph nodes. The five-step approach of GETTA is easy to learn and can be adapted for resecting both benign and malignant thyroid and parathyroid diseases.

Reconstruction of Vocal Fold Medial Surface 3D Trajectories: Effects of Neuromuscular Stimulation and Airflow.

Analysis of medial surface dynamics of the vocal folds (VF) is critical to understanding voice production and treatment of voice disorders. We analyzed VF medial surface vibratory dynamics, evaluating the effects of airflow and nerve stimulation using 3D reconstruction and empirical eigenfunctions (EEF). In vivo canine hemilarynx phonation. An in vivo canine hemilarynx was phonated while graded stimulation of the recurrent and superior laryngeal nerves (RLN and SLN) was performed. For each phonatory condition, vibratory cycles were 3D reconstructed from tattooed landmarks on the VF medial surface at low, medium, and high airflows. Parameters describing medial surface trajectory shape were calculated, and underlying patterns were emphasized using EEFs. Fundamental frequency and smoothed cepstral peak prominence (CPPS) were calculated from acoustic data. Convex-hull area of landmark trajectories increased with increasing flow and decreasing nerve activation level. Trajectory shapes observed included circular, ellipsoid, bent, and figure-eight. They were more circular on the superior and anterior VF, and more elliptical and line-like on the inferior and posterior VF. The EEFs capturing synchronal opening and closing (EEF1) and alternating convergent/divergent (EEF2) glottis shapes were mostly unaffected by flow and nerve stimulation levels. CPPS increased with higher airflow except for low RLN activation and very dominant SLN stimulation. We analyzed VF vibration as a function of neuromuscular stimulation and airflow levels. Oscillation patterns such as figure-eight and bent trajectories were linked to high nerve activation and flow. Further studies investigating longer sections of 3D reconstructed oscillations are needed. N/A, Basic Science Laryngoscope, 134:1249-1257, 2024.

Vocal Cord Paralysis after Repair of Esophageal Atresia.

Etiology of vocal cord paralysis (VCP) and laryngeal dysfunction may be congenital or surgical trauma of recurrent and superior laryngeal nerves. We assessed the incidence, risk factors, and morbidity of VCP after repair of esophageal atresia (EA). Medical records of 201 EA patients from 2000 to 2022 were reviewed for this retrospective study. Postrepair vocal cord examination (VCE) included awake nasolaryngeal fiberoscopy by otolaryngologist or laryngoscopy under spontaneous breathing anesthesia. Before 2017, postoperative VCE was performed in symptomatic patients only and routinely after 2017. Overall, VCE was performed on 79 (38%) patients (52 asymptomatic), whereas 122 asymptomatic patients underwent no VCE. VCP was diagnosed in 32 of 79 patients (right 12, left 10, and bilateral 10; symptomatic 25 and asymptomatic unilateral 7) corresponding with extrapolated overall VCP incidence of 16 to 24% among 201 patients including asymptomatic ones. Ten patients (bilateral VCP 8 and left VCP 2) required tracheostomy. Of 10 patients with bilateral VCP, three underwent laryngotracheal expansion surgery (left VC lateralization in one and laryngoplasty in two with acquired subglottic stenosis), three remained tracheostomy dependent, three were off tracheostomy, and one died of complications after redo esophageal reconstruction. All patients with unilateral VCP managed without tracheostomy. Cervical dissection or ostomy formation was a major risk factor of VCP. Repair of EA is associated with a considerable risk of VCP and associated morbidity. Cervical EA surgery significantly increased the risk of VCP. Bilateral VCP may eventually require laryngotracheal expansion surgery.

Singing After Superior Laryngeal Nerve Weakness: A Story of Hope

Singing After Superior Laryngeal Nerve Weakness: A Story of Hope

Indications and Short-Term Outcomes for In-Office Therapeutic Superior Laryngeal Nerve Block.

Superior laryngeal nerve (SLN) block consists of injection of steroid and anesthetic at the internal branch of the SLN entry site. Prior case series have demonstrated beneficial effects on neurogenic cough. SLN blocks have also recently shown benefit for paralaryngeal pain. We describe short-term outcomes for multiple symptoms of irritable larynx syndrome (ILS) including neurogenic cough, dysphonia related to laryngeal hypersensitivity, inducible laryngeal obstruction (ILO), paralaryngeal pain, and isolated globus. Retrospective review from 2 institutions of patients undergoing a single SLN block for the indications listed. Variables include age, sex, indication(s), known vagus neuropathy, and patient-reported outcomes at short-term follow-up. A total of 209 patients were included (59 males, 150 females; age: 58 ± 13 years). Twenty-six patients (12%) had a history of a vagus nerve injury. Indications included neurogenic cough (n = 149), dysphonia related to laryngeal hypersensitivity (n = 66), paralaryngeal pain (n = 50), ILO (n = 23), and isolated globus (n = 3). Some patients had multiple indications. Significant improvements in patient-reported measures occurred after a single SLN block within 2 to 4 weeks for neurogenic cough (cough severity index; 25.2 ± 11.2 to 19.0 ± 12.8; P < .001), dysphonia (voice handicap index-10; 22.1 ± 12.2-18.0 ± 13.3; P = .005), and ILO (dyspnea index; 21.0 ± 14.9-14.7 ± 15.7; P = .017). Subjective pain improved in 23 of 39 patients with paralaryngeal pain. There was no observed improvement for isolated globus. Presence of known vagal neuropathy or therapy around the time of SLN block did not affect outcome. SLN block can be an effective component of treatment for a variety of ILS symptoms. Patients may experience some improvement after 1 injection. Symptoms of irritable larynx syndrome, such as neurogenic cough, paralaryngeal pain, inducible laryngeal obstruction, and dysphonia related to laryngeal hypersensitivity can be challenging to manage. In-office Superior Laryngeal Nerve blocks can serve as a quick, well tolerated, adjunctive treatment with positive short-term outcomes. 4.

Effectiveness and Safety of Percutaneous Treatment in Lesions Suggestive of Thyroid Cancer (Bethesda V and VI-T1aN0M0) Compared to Surgical Treatment: Systematic Review and Meta-Analysis.

Thyroid nodules are common entities, with 5% malignancy. Differentiated thyroid cancer represents 90% of thyroid malignancies, with papillary carcinoma being the most common. Management is generally surgical; among its complications are injury to the recurrent laryngeal and superior laryngeal nerve, causing hoarseness, postsurgical hypoparathyroidism, hypothyroidism, and pain. Other noninvasive percutaneous interventions of thermal ablation such as microwave, radiofrequency, or laser incur lower costs and could be an option for treatment. To determine the effectiveness and safety of thermal ablation in lesions suspected of thyroid cancer (Bethesda V and VI/T1aN0M0) compared to surgical treatment. Systematic review/meta-analysis of observational studies and clinical trials. Database search includes MEDLINE/PUBMED, Embase, Scopus, Scielo, and BVS/LILACS. Studies on patients over 18 years of age with lesions suspicious of thyroid cancer were included. A total of 10 studies were obtained, with 2939 patients: 1468 subjected to thermal ablation and 1471 to surgery. Regarding effectiveness, no differences were found in local recurrence [relative risk (RR) 1.17 (95% CI 0.69-1.99)] and cervical lymph node metastasis [RR 0.76 (95% CI 0.43-1.36)]. Regarding safety, infection [RR 0.29 (95% CI 0.05-1.74)], hematoma [RR 0.57 (95% CI 0.17-1.94)], and transient hoarseness [RR 0.77 (95% CI 0.39-1.51)] were evaluated, without difference. However, permanent hoarseness had significant differences in favor of thermal ablation [RR 0.29 (95% CI 0.11-0.75)]. Thermal ablation for the treatment of T1aN0M0 papillary thyroid carcinoma is equally effective when compared to surgical techniques and offers a better safety profile, particularly in permanent hoarseness.

Perineural Invasion of Superior and Inferior Laryngeal Nerves in Advanced Stage Squamous Cell Carcinoma of the Larynx: A Case Series and Review.

To evaluate bilateral superior and recurrent laryngeal nerves for tumor spread in patients of advanced-stage laryngeal carcinoma undergoing surgical resection. A prospective study was conducted including biopsy-proven cases of laryngeal squamous cell carcinoma (SCC) that were planned for total laryngectomy. Patients with metachronous or synchronous SCC were excluded from the study. All patients underwent total laryngectomy, where both superior and recurrent laryngeal nerves were harvested along with the specimen, and the proximal ends of the nerves were marked for reference. Perineural invasion (PNI) was assessed in nerves within the tumor and in bilateral extra-laryngeal nerves. The study included 22 patients with a mean age of 58 years. Intra-tumoral PNI was found in 7 of the 22 cases (32%). The free nerve margins of superior and recurrent laryngeal nerves, which were examined from proximal to distal orientation, showed no tumor infiltration in any of the cases. Perineural invasion of minor nerves constitutes a major pathway of spread. On the contrary, invasion of superior or recurrent laryngeal nerves does not constitute a route for tumor spread. Hence, there is no need to extend the surgical boundary for total laryngectomy to include these major nerves separately.