Branch Of Superior Laryngeal Nerve Research Articles

Role of Intraoperative Neuromonitoring to Identify External Branch of Superior Laryngeal Nerve During Thyroidectomy

Role of Intraoperative Neuromonitoring to Identify External Branch of Superior Laryngeal Nerve During Thyroidectomy

Varying Course of External Branch of Superior Laryngeal Nerve (EBSLN) and Recurrent Laryngeal Nerve (RLN) in Thyroidectomy-An Observational Study.

Surgical management of a diseased thyroid depends on sonological and pathological evaluation and thereby, planning of the surgery. The definite surgery has two objectives: removal of the diseased gland and preservation of the nerves, namely EBSLN(External Branch of Superior Laryngeal Nerve) and RLN (Recurrent Laryngeal Nerve) and the Parathyroid glands.The objectives of the study were:(1) To identify the course of the RLN and EBSLN of both sides, during Thyroidectomy. (2) To discern various anatomical landmarks, the relations of the two nerves with them and anatomical variations, if any. In this Prospective observational study, fifty selected goitre patients underwent various types of thyroidectomies based on sonological and cytological criteria. The course and anatomical variations of EBSLN and RLN were photo-documented and results were analysed. Most of the EBSLN were found as Cernea type 1 type (25 out of 50), followed by Cernea type 2a (comprising 36%). The least common was type 2b. It was found that 36 out of 50 (72%) of RLN passed posterior to Inferior Thyroid Artery (ITA). Moreover, before piercing cricothyroid joint, the RLN showed bifurcation in 13 out of 50 subjects (26%), 1 participant had trifurcation and the remaining 36 (72%) had a single trunk. The EBSLN shows relation to the horizontal plane passing through the upper pole of the thyroid gland and it is more prone to get damaged when it passes within less than 1cm to the plane. The RLN has various relations to the distinct anatomical landmarks thereby helping in safe dissection of the nerve. The study also noted the RLN in relation to ITA and branching before entering into the cricothyroid joint.

Voice Changes Without Laryngeal Nerve Alterations After Thyroidectomy: The Need For Prospective Trials - A Review Study.

Thyroidectomy is a commonly performed surgical procedure that is offered for different thyroid pathologies. The most frequent complication after total thyroidectomy is transient or permanent hypoparathyroidism followed by transient or permanent recurrent laryngeal nerve palsy. Patients may experience voice impairment despite intact laryngeal nerve function. These patients are of special interest because they experience subjective symptoms which are difficult to measure and therefore to treat. The Voice Handicap Index (VHI) and VHI-10 are the most commonly used subjective questionnaires. Their results correlate with objective findings. Female sex, in particular after menopause, is a dominant factor for developing voice impairment after thyroidectomy. The extent of neck surgery and the weight and volume of the removed thyroid correlates directly with both objective and subjective voice impairment after surgery. Videolaryngostroboscopy should be considered to examine vocal cord pathologies in this patient group. Surprisingly, there are no studies showing that speech and voice therapy are beneficial for patients with voice alterations but with intact laryngeal nerves. While recurrent laryngeal nerve (RLN) paralysis can be evaluated by objective exams postoperatively, we are still left with the issue of possible partial or complete external branch of superior laryngeal nerve (EBSLN) injury. It is therefore quite difficult to segregate neural (RLN and EBSLN) and non-neural voice change populations, regardless of the method of literature evaluation. Perhaps patients' perspectives on how they experience voice functionality should play a superior role in deciding which patients should be investigated further with laryngoscopy, acoustic or perceptual analysis, and which patients should be offered treatment.

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.

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

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. 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. 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 0.93mm (0.72-1.15mm [±0.83 SD]), located 0.34cm [-1.62-2.43cm (±0.96 SD)] posterior to the angle of the mandible, 1.28cm (-1.33 to 3.42cm (±0.93 SD)] inferiorly; 2.84cm (0.51-5.14cm±1.09 SD) anterior to the tip of the mastoid process, 4.51cm (2.82-6.39cm±0.76 SD) inferiorly; 1.64cm [0.57-3.78cm (±0.89 SD)] superior to the bifurcation of the carotid artery. 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.

Lateral Approach to Thyroid Surgery: An Alternative Open Thyroidectomy Technique

Background: Thyroidectomy is one of the common surgical procedures for thyroid related various pathology. Midline approach is the classical and common in which thyroid gland is approached after splitting the strap muscles in midline. The objective of this research is to elaborate the surgical technique of lateral thyroid approach for hemi-thyroidectomy, also to measure the efficacy in preserving the important anatomical structures and to assess the complications. Materials: A cross-sectional study was conducted in the department of ENT-Head and Neck Surgery of Bharatpur Hospital, Chitwan, Nepal during January 2019 to March 2021. Benign thyroid diseases that required hemi-thyroidectomy were included in this study. Surgical technique was discussed with special focus for access of superior pedicle and preservation of important anatomical structures. Results: Among 36 cases most of those 16(44.4%) were operated after 1 year of disease occurrence. Not a single case was undergone strap muscle cutting or sacrifice of superior belly of omohyoid muscle. Recurrent laryngeal nerve was found in 94.4% (33 cases). External branch of superior laryngeal nerve (EBSLN) was in 91.7 %( 33) cases. Superior parathyroid glands were found in majority of the cases but not found in 8.3 %( 3). Inferior parathyroid glands were found in all cases. Post-operative drainage was 38 ml(mean). Conclusion: Vital structures were preserved in more than 90% cases and major complication occurred in none of the cases. We conclude that this approach is good, safe and comfortable to the surgeon.

Clinical application of modified fistulectomy in the treatment of congenital pyriform sinus fistula based on segmental anatomy of fistula

Objective:To discuss the clinical application and significance of the modified piriform fossa fistulectomy based on segmental anatomy of fistula. Methods:The clinical data of 84 patients with CPSF treated by modified pyriform sinus fistulectomy were analyzed retrospectively. The modified piriform fossa fistula resection adopts the fistula anterograde anatomy method to fine dissect the fistula. The operation procedure can be summarized into four parts: retrograde anatomy of recurrent laryngeal nerve, anatomy of external branch of superior laryngeal nerve, anterograde anatomy of fistula and partial thyroidectomy. Results:All 84 patients successfully completed the operation and discharged from the hospital. The operation time was（64.6±20.0） min, the intraoperative bleeding was（19.6±13.0） mL, and the average hospital stay was（6.8±1.1） d. Postoperative infection occurred in 1 case（1.19%）, temporary vocal cord paralysis in 1 case（1.19%）, no bleeding, pharyngeal fistula, dysphagia, permanent vocal cord paralysis and choking cough. The incidence of complications was 2.3%（2/84）. No complications such as permanent vocal cord paralysis and hypothyroidism occurred. Follow up for 57-106（Median 74） months showed no recurrence. Conclusion:A modified procedure based on segmental dissection of the fistula not only simplifies the traditional procedure, but also procedures the specific steps to provide a targeted and precise resection, which provides a proven surgical solution for complete eradication of the lesion and significantly reduces complications and recurrence.

Preservation of superior laryngeal nerve in transoral surgery: A technology to enhance the recovery of swallowing function after surgery of hypopharyngeal carcinoma

ObjectivesWe intended to preserve the internal branch of superior laryngeal nerve in transoral surgery of hypopharyngeal squamous cell carcinoma and observe swallowing function recovery. Methods26 patients with hypopharyngeal squamous cell carcinoma underwent transoral surgery with the preservation of internal branch of superior laryngeal nerve. Sensation in the pharyngolaryngeal mucosa was tested by flexible laryngoscope and swallow function was evaluated by water swallow test and MD Anderson Dysphagia Inventory questionnaire after surgery. ResultsSurgeries were successfully performed in all patients. The internal branch of superior laryngeal nerve were preserved in all patients. Testing of mucosa sensation revealed the presence of the cough reflex in most patients. The water swallow test showed that 12 cases (46.15%) on the 1st day, 23 cases (88.46%) on the 7th day and 25 cases (96.15%) on the 14th day after operation had normal swallowing function. The mean score of MD Anderson Dysphagia Inventory was 98 on the 14th day after operation. All patients achieved an oral soft diet at a median of 3 days (range, 2–6 days), full normal oral diet at a median of 5.5 days (range, 4–10 days) and removal of the nasogastric tube at a median of 6 days (range, 5–11 days). During the two-year follow-up, 3 patients recured, 1 patient died of lung metastasis. ConclusionsPreserving of the internal branch of superior laryngeal nerve in transoral surgery is feasible, and it can help to achieve a satisfactory recovery of the swallowing function after surgery of hypopharyngeal squamous cell carcinoma.

NERVE MONITORING IN THYROID SURGERY: A RETROSPECTIVE COHORT STUDY

Background:The proximity of the Recurrent Laryngeal and External Branch of Superior Laryngeal Nerve to the Thyroid Gland has been a key factor for a profound interest of surgeons and clinicians in the clinical outcomes and Vocal changes in the post operative period in the patients undergoing thyroid surgery. The presence of Recurrent Laryngeal nerve in proximity of Thyroid poses a significant risk of damage to the nerve during surgery. The Recurrent Laryngeal Nerve SuppliesLarynx below the level of vocal cords and all the muscles except Cricothyroid. Posterior Cricoarytenoid, the only abductor of vocal cord is also supplied by this nerve. So, any damage to the nerve during surgery causes significant changes in pitch and texture of voice, commonly referred to as hoarseness.Intra-operative Nerve Monitoringwas introduced about 50 years ago and various neuromonitoring methods (glottis pressure method, glottic monitoring method, insertion of needle electrodes invocal cords endoscopically or through cricothyroid membrane, laryngeal palpationmethod, and monitoring via endotracheal tube with surface electrodes) have been utilized. We present a retrospective cohort study to surmise the effect of the use of Intraoperative nerve monitoring devices during Thyroid surgery and compare the clinical outcome in two cohorts. First, the study group where the nerve monitoring was used intraoperatively and the Second, where no intraoperative nerve monitoring was used. All the Patients included in the study underwent Thyroid surgery in the Department of Otorhinolaryngology-Head and Neck Surgery, MBS Hospital, Kota. Methods:This retrospective cohort study includes 100 patients as per the inclusion criteria specified in this article and all the included patients were studied after dividing them into two groups with one group where intraoperative nerve monitoring was used and the other group where no nerve monitoring was used. Each group had 50 patients each. All the patients are regularly documented for with Video Laryngoscopic Examination as a standard. All the data collected from the archives and put to statistical evaluation to analyse the data Age wise, Sex wise, Residential address wise, according to mean Thyroid volume, according to presenting complaints, according to history, according to mean operative time, according to the type of Nerve Injury, according to duration of hospital stay and other parameters as followed in the study. Results: On appropriate statistical analysis of the data, it was seen that there were no demographic variables within groups that ensured statistical similarity in the groups, there was also no statistical correlation of functional preservation attributable to mean Thyroid volume. The incidence of nerve injury was higher in the patients who got themselves operated for the malignancy of thyroid and the revision surgeries. The patients being operated for controlled toxic goitre reported ni nerve injury in the post operative period. The intraoperative nerve monitoring reported lower mean time required to do the surgery. There was a similar incidence of permanent and transient nerve injury in both the cohort groups.

Surgical landmarks for identification and preservation of the internal branch of the superior laryngeal nerve

To determine the topographical anatomic features of the internal branch of the superior laryngeal nerve (ibSLN) at the thyrohyoid membrane entrance area in relation to certain consistent anatomical structures. METHODS: Twenty-two fresh adult head cadavers (9 male, 13 female; age range 52-95years) with no signs of abnormality in the neck were dissected to determine the anatomic relationship of ibSLN and superior border of thyroid cartilage, thyroid notch, carotid bifurcation, hyoid corpus, and hyoid greater cornu. The topographical relationship between ibSLN and superior border of thyroid cartilage, thyroid notch, carotid bifurcation, hyoid corpus, and hyoid greater cornu was identified bilaterally in all cadavers. According to the measures, danger zone and safe zone areas for surgical could be predicted and for surgical manipulations as well. We provided the surgical anatomy and important landmarks for determining the internal branch of superior laryngeal nerve in the thyrohyoid membrane entrance region to avoid surgical damage during surgeries of this region.

Effect of mouse nerve growth factor combined with the exposure of the external branch of superior laryngeal nerve on voice changes after thyroidectomy: a prospective non-randomized controlled trial.

The superior laryngeal nerve (SLN) injury may also affect vocal fold function and voice quality. It is efficient yet simple approach to expose the external branch of the superior laryngeal nerve (EBSLN). Neurotrophic agent mouse nerve growth factor (mNGF) to treat patients after thyroid surgery, and found it had significant efficacy in improving the voice of patients. However, the potential effectiveness and safety of mNGF combined with EBSLN were unclear. In this study, 96 patients who suffered from hoarseness after thyroidectomy at Hangzhou First People's Hospital between January 2018 and October 2019 were screened and divided into the control group and the observation group by patients' choice. In the control group, the SLN was not exposed. In the observation group, the SLN was exposed. The mNGF treatment was administered for observation group once a day at 20 µg each time for 4 weeks. The data of acoustic voice indicators was analysis by univariate analyses. Patients in both groups were followed up for more than 6 months. The rate of SLN damage was compared between two groups. The baseline clinical characteristics of the two groups showed no statistic difference. The results showed that the fundamental frequency was significantly lower 1 month after surgery than 3 days after surgery in both groups. The fundamental frequency perturbation, shimmer, maximum phonation time, highest fundamental frequency, and dysphonia severity index in 1 month after surgery were significantly higher than they were 3 days after surgery (all P<0.001). There was no significant difference in the postoperative harmonic-to-noise ratio between the 2 groups (P=0.426). MNGF combined with the exposure and protection of the EBSLN effectively may prevent voice damage after thyroid surgery.

The feasibility of laryngeal nerve protection during thyroidectomy using sternocleidomastoid intermuscular approach with intraoperative neuromonitoring: a case series and step-by-step description of surgical procedure.

Thyroid surgery is increasingly demanding in terms of cosmetic neck outcomes and protection of anterior neck function, so we have adopted an alternative sternocleidomastoid intermuscular approach (SMIA) for open/conventional thyroidectomy. The protection of recurrent laryngeal nerve (RLN) and external branch of superior laryngeal nerve (EBSLN) is the key and difficult point in thyroid surgery. The aim of this study was to testify the feasibility of RLN and EBSLN functional protection during SMIA thyroidectomy with the intraoperative neuromonitoring. A total of 39 patients and 39 RLN and EBSLNs who underwent monitored SMIA thyroidectomy were included. Thyroid gland is revealed and excised anterior to the cervical sheath between the sternal and clavicular heads of the sternocleidomastoid muscle. Standardized intraoperative neuromonitoring (IONM) procedures and postoperative laryngeal examination were performed to audit the SMIA. Following the four-step method, V1, R1, R2, and V2 were monitored and the signal values were recorded. Statistical analysis was used to evaluate the change of IONM amplitude of RLN, combined with the results of laryngoscopy before and after operation to determine the status of RLN. EBSLN injuries were identified from changes in cricothyroid muscle (CTM) twitch and EMG. SMIA video vignette is detailed. All RLN and EBSLNs [17 on the left and 22 on the right] were monitored in 39 patients [5 men, 34 women; mean age 34.1±8.7 years; mean body mass index 22.5 (±3.0, 17.0-30.8) kg/m2] undergoing SMIA. For RLN of the affected side, we compared the V2 and V1 (1,236±672 vs. 1,240±428, P=0.973), R2 and R1 (1,676±778 vs. 1,656±765, P=0.849) signals separately, and the results were not statistically different (P>0.05). Comparing the V1 (1,240±428 vs. 1,309±395, P=0.601) signals of the bilateral recurrent laryngeal nerve, there was no statistical difference (P>0.05). CTM twitch and EMG were preserved. The SMIA technique appears feasible. RLN and EBSLN are easier to be exposed during thyroid surgery of SMIA, which is beneficial to the neuroprotection during the operation. At the same time, it can protect the anterior cervical function and improve the cosmetic effect after operation.

Injury of the external branch of the superior laryngeal nerve in thyroid surgery

Injury of the external branch of the superior laryngeal nerve is one of the complications in thyroid surgery, the frequency of which varies within very wide limits due to the difficulties in diagnosis. The complaints relate to a change in voice tone, which significantly impairs the quality of life of patients, especially those with voice profession. The most accurate specific method for diagnosis is electroneuromyography but this technique is very difficult to perform and not used in routine practice. To diagnose the lesion of the external branch of superior laryngeal nerve the authors used laryngoscopy, laryngostroboscopy and spectral analysis of the voice, which revealed the frequency of nerve injury and dynamic monitoring of voice recovery in the patient.&#x0D; Objective — to examine the frequency of lesions of the external branch of superior laryngeal nerve in thyroid surgery on the basis of changes in the laryngoscopic picture, spectral analysis of the voice and dynamic monitoring of their recovery during treatment&#x0D; Materials and methods. The study was conducted in the surgical department of the Ukrainian Scientific and Practical Center for Endocrine Surgery, Transplantation of Endocrine Organs and Tissues MOH of Ukraine with involvement of 241 operated patients. Examination of the larynx and voice examination were performed before surgery, on the 2 — 3 days and 6 and 12 months after surgery. Diagnosis was performed using methods: videolaryngoscopy, videolaryngostroboscopy, spectral analysis of the voice.&#x0D; Results. Clinical signs of trauma to the external branch of the superior laryngeal nerve were found in 8 (3.3 %) patients out of 241 operated. Patients received a course of phonopedia and stimulation therapy in the absence of contraindications. Voice recovery over time was recorded in 7 (87.5 %) patients, no voice recovery in 1 (0.4 %).&#x0D; Conclusions. Injury of the external branch of superior laryngeal nerve after surgery on the thyroid gland is a complication after thyroid surgery which does not happen often (3.3 %). This complication is very difficult to detect, considering inconspicuous symptoms, the lack of specificity of the laryngoscopic picture and the peculiarities of diagnostic methods. It is not always possible to fully restore the voice when the external branch of the superior laryngeal nerve is damaged (permanent injury accounts for 0.4 % of the total number of operations on the thyroid gland and 85.0 % of the total number of patients with damage to the external branch of the superior laryngeal nerve), which requires dynamic monitoring of patients and timely treatment administration.&#x0D;

Stepwise approach to preserve the external branch of superior laryngeal nerve during thyroidectomy

BackgroundMost of the surgeons tend to avoid exposing and identification the external branch of the superior laryngeal nerve (EBSLN) during thyroidectomy. In this study, our aim is to assess sequential steps to ligate superior thyroid vessels safely away from the External branch of superior laryngeal nerve (EBSLN).MethodsThis prospective case series study was conducted on 60 patients going for either total or hemi thyroidectomy in a tertiary teaching hospital between January 2016 and June 2019. During thyroidectomy, firstly we skeletonized the upper pole of the thyroid gland by its capsular dissection followed by anterolateral down retraction of the superior pole. Then, entry and opening of the cricothyroid space and lastly clamping and ligating superior thyroid pedicle close to the upper pole away from EBSLN.ResultsThis study included 60 cases; 19 total thyroidectomy and 41 hemi thyroidectomy with 79 superior thyroid vessels ligation and EBSLN at risk. In all patients, no evidence of superior laryngeal nerve (SLN) palsy or bleeding was detected. Postoperative video laryngoendoscopy showed apparently normal mobility, length, level, and position of the vocal folds with symmetry of the larynx. The patients’ voice showed no changes from preoperative evaluation in all studied patients at 3 months postoperative evaluation. No patients complained of any changes in their voice or voice activities.ConclusionThe described stepwise approach for preservation of the EBSLN serves to completely remove the superior pole of the thyroid gland and ligate superior thyroid vascular pedicle without risk of SLN injury.

Cernea's classification of the External Branch of the Superior Laryngeal Nerve during Microscopic Thyroidectomy at Gandaki Medical College, Pokhara

Background: Preservation of the external branch of the superior laryngeal nerve (EBSLN) during thyroidectomy is important because its injury may lead to frequent occurrence of vocal fatigue and the inability to perform phonation. The objective of the study was to identify and classify the nerve as per Cernea's classification using operating microscope during thyroidectomy Method: Between January 2017 to December 2019, we evaluated 50 patients for the position of external branch of superior laryngeal nerve, who underwent microscopic thyroid surgeries in the department of ENT- head and neck surgery at Gandaki Medical College. Results: In our study, we dissected a total 59 superior poles of thyroid from 50 patients and identified the nerve in all the cases. Of the total superior poles, 36 (61.01%) had type IIa EBSLN among which 24 was on the right side and 12 on the left followed by 19 (32.20%) patients with type IIb EBSLN among which 8 on right and 11 on left side. There were only 4 poles (6.77%) of type I with 3 on the right and 1 on the left side. Conclusion: The EBSLN can be very efficaciously identified during a microscope assisted thyroidectomy. Cernea type 2a and 2b EBSLNs are in position to be at high risk of injury during ligation of the superior vascular pedicle, which can be avoided by prompt identification through a microscope and a meticulous extra capsular dissection technique.

Correlation Between Objective and Subjective High-Pitched Voice Impairment in Patients After Thyroid Surgery.

ObjectivesHigh-pitched voice impairment (HPVI) is not uncommon in patients without recurrent laryngeal nerve (RLN) or external branch of superior laryngeal nerve (EBSLN) injury after thyroidectomy. This study evaluated the correlation between subjective and objective HPVI in patients after thyroid surgery.MethodsThis study analyzed 775 patients without preoperative subjective HPVI and underwent neuromonitored thyroidectomy with normal RLN/EBSLN function. Multi-dimensional voice program, voice range profile and Index of voice and swallowing handicap of thyroidectomy (IVST) were performed during the preoperative(I) period and the immediate(II), short-term(III) and long-term(IV) postoperative periods. The severity of objective HPVI was categorized into four groups according to the decrease in maximum frequency (Fmax): <20%, 20-40%, 40-60%, and >60%. Subjective HPVI was evaluated according to the patient’s answers on the IVST.ResultsAs the severity of objective HPVI increased, patients were significantly more to receive bilateral surgery (p=0.002) and have subjective HPVI (p<0.001), and there was no correlation with IVST scores. Among 211(27.2%) patients with subjective HPVI, patients were significantly more to receive bilateral surgery (p=0.003) and central neck dissection(p<0.001). These patients had very similar trends for Fmax, pitch range, and mean fundamental frequency as patients with 20-40% Fmax decrease (p>0.05) and had higher Jitter, Shimmer, and IVST scores than patients in any of the objective HPVI groups; subjective HPVI lasted until period-IV.ConclusionThe factors that affect a patient’s subjective HPVI are complex, and voice stability (Jitter and Shimmer) is no less important than the Fmax level. When patients have subjective HPVI without a significant Fmax decrease after thyroid surgery, abnormal voice stability should be considered and managed. Fmax and IVST scores should be interpreted comprehensively, and surgeons and speech-language pathologists should work together to identify patients with HPVI early and arrange speech therapy for them. Regarding the process of fibrosis formation, anti-adhesive material application and postoperative intervention for HPVI require more future research.

Application value of intraoperative neuromonitoring plus "classification of EBSLN" to protect the external branch of the superior laryngeal nerve

Objective: To investigate the application efficacy of the "classification of external branch of superior laryngeal nerve (EBSLN)" combined with intraoperative neuromonitoring (IONM) in the dissection of EBSLN for protecting the nerve from injuery, compared with ligation of branches of the superior thyroid vessels without attempts to visually identify the nerve. Methods: A prospective randomized controled study was performed in our center. Patients subjected to thyroidectomy from January 2017 to June 2019 were randomly divided into 2 groups, patients in experimental group underwent thyroidectomy and "classification of EBSLN" with IONM to dissect EBSLN, and patients in control group received synchronous surgery without attempts to visually identify the nerve. The anatomical subtypes of EBSLN in experimental group were recorded. The voice handicap index 10 (VHI-10) score was evaluated and the movement of bilateral vocal cords was examined by laryngoscope before surgery, 1 month, 3 months, and 6 months after surgery, respectively. SPSS 26.0 statistical software was used for statistical analysis. Results: Among the 1 377 EBSLN from 827 patients (317 males and 510 females, aged 24-58 years old), 691 EBSLNs in experimental group and 686 EBSLNs in control group. Totally 98.3% of EBSLNs in experimental group were identified by IONM including 16.4% (113/691) for type Ⅰ, 21.3% (147/691) for type Ⅱa, 31.4% (217/691) for type Ⅱb, 10.4% (72/691) for type Ⅲa, 3.9% (27/691) for type Ⅲb, 16.6% (115/691) for type Ⅲc. There was no statistical significance difference in baseline data between 2 groups (all P>0.05). All patients were followed up for more than 6 months. The postoperative nerve injury rate of experimental group was significantly lower than that of control group (1.2% vs. 7.5%, χ²=12.659, P<0.001), and the VHI-10 scores and laryngoscope results of experimental group were better than those of control group in three follow-up visits (P<0.001). With postoperative laryngoscope examination, 3 patients in the experimental group and 23 patients in the control group showed vocal cord relaxation, bilateral oblique asymmetry and other phenomena, which were considered as the results of permanent injury. Other patients with symptoms were relieved to varying degrees during the follow-up, and their symptoms were considered as the results of temporary injury. Conclusion: IONM combined with "classification of EBSLN" can reduce significantly the risk of EBSLN injury in thyroidectomy, which is better than direct ligation of branches without attempts to visually identify the nerve.

Improving classification of the external branch of the superior laryngeal nerve with neural monitoring: a research appraisal and narrative review.

To review the published literature on external branch of superior laryngeal nerve (EBSLN) neural monitoring and propose a new EBSLN classification system using intraoperative neural monitoring (IONM). The injury rate of the external branch of the superior laryngeal nerve (EBSLN) in thyroid surgery is 0-58%. Symptoms of EBSLN injury are not consistent, and patients often complain of modification of the voice timbre with the preservation of vocal cord function. Standards for the diagnosis of EBSLN injury are lacking. The PubMed database was searched using the terms 'External branch of the superior laryngeal nerve' and 'Intraoperative neuromonitoring' from 2010 through March 2020. This paper reviewed the anatomy of the EBSLN, the diagnosis and treatment of injury, and the application of IONM in the EBSLN. The traditional EBSLN classification method was analyzed and compared with our new classification method. The diagnosis of EBSLN injury is a problem that still needs to be resolved. For anatomic classifications of the EBSLN, we found that the conventional classification systems may not accurately reflect the real status of the EBSLN and the surgical risks that may occur intraoperatively. Using IONM, we developed an EBSLN classification method that was consistent with conventional diagnosis and treatments and can be widely and easily utilized during surgery.

Patterns of Laryngeal Nerves Injuries Following Thyroid Surgery in Al-Imamein Al-Kadhmein Medical City

Background: Morbidity after thyroid surgery related to injuries to parathyroid, recurrent laryngeal nerve (RLN) and external branch of superior laryngeal nerve (EBSLN), mostly due to unawareness of the anatomical variations and lack of meticulous dissection added to that patient comorbidity and type of goiter. Objective: To assess the incidence of nerves injuries (RLN and EBSLN) and evaluation of the risk factors for nerves injuries. Methods: A prospective study included 250 patients admitted to the General Surgical Unit at Al-Imamein Al-kadhimein Medical City from the first of October 2014 to the end of October 2017. Evaluation of nerves injuries (RLN and EBSLN) with regard to thyroid pathology, types of resection, age and gender. Thyroidectomies were done by different surgical teams. Patients with recurrent goiter, prior cervical surgery and preexisting vocal cord paralysis were excluded. Vocal cords assessment was done preoperatively, intraoperatively at time of extubation and postoperatively. Patients with injury to the RLN were managed accordingly and followed up by serial examination for 6-12 month, while patients with symptoms of EBSLN injuries were followed depending just on clinical feature due to lack of diagnostic facilities. Results: There were 78 (31.2%), 172 (68.8%) male and females subsequently. The age range was (18-70) years and mean±SD was (44±11.9). Multinodular goiter was the main presentation in (168 patients), while thyroiditis was the least (6 patients). Injury to RLN was reported in 8 (3.2%) patients, 3 had unilateral and 5 had bilateral. Permanent damage documented in 2 patients. There was a significant RLN injury association with malignancy and total thyroidectomy. EBSLN injury have been reported in 55 patients (22%), it was transient in 43 patients and permanent in 12 patients. Conclusion: Nerve damage after thyroidectomy is not uncommon and affect significantly on quality of life. Careful dissection and awareness of anatomical variation is essential. Majority of injuries were transient and recovered spontaneously. Immediate intervention is not recommended unless airway compromisation ensure. Keywords: RLN, EBSLN, thyroidectomy Citation: Jaber SMA, Abdulhassan BA, Hussien HK, Al-Helfy SH. Patterns of laryngeal nerves injuries following thyroid surgery in Al-Imamein Al-Kadhmein Medical City. Iraqi JMS. 2021; 19(1): 10-17. doi: 10.22578/IJMS.19.1.2