18.Dr Manya thakurRoy.cdr INTRODUCTION For many years surgeons have ligated the superior pole of the thyroid gland near the entrance of the vessels aiming to avoid injury to External Laryngeal Nerve. There have been numerous modications in the techniques of Thyroid surgeries with better understanding of the anatomy and the physiology of the thyroid gland. The clinical signicance of superior laryngeal nerve (SLN) has been clearly overshadowed by emphasis on recurrent laryngeal nerve. The principles of head and neck surgery are based on identication & preservation as opposed to avoidance of important structures. Paralysis of the SLN can be signicant to those whose career depends heavily on full range of voice e.g singers teachers , hawkers , telemarketing professionals to name a few. Damage to the nerve can manifest as paralysis to the cricothyroid muscle. Mostly it is asymtomatic, but clinical symptoms of unilateral injury may include hoarse monotonus and breathy voice. Bilateral injury will have same changes with easy fatigue of voice. The clinician may nd signs of bowing and inferior displacement of affected cord on 1Laryngoscopy. The present study is a nonrandomized prospective study which focuses primarily on intra operative identication and preservation of EBSLN during thyroid surgery in 90 patients. MATERIAL AND METHODS This study was non randomized prospective study conducted at Department of ORL & HNS, Tertiary Care Center India. The Subjects were FNAC proven euthyroid patients undergoing thyroid surgery in ENT Department of SAIMS from July 2011 to July 2014.The patients were pre operatively assessed to exclude vocal cord palsy by Video Laryngoscopy & Voice Analysis. The Exclusion criteria was Patients presenting with history of recent hoarseness or who have received neck radiation and with history of previous neck surgery, anaplastic thyroid carcinoma, Grave's disease, completion thyroidectomy and abnormal vocal cord function pre-operatively Initially cadaver dissection was done in Dept of Anatomy and the course of the nerve and position was studied Intra operatively (as shown in Fig 1 -9). An attempt to identify and preserve External Laryngeal Nerve was made during surgery by individual ligation and skeletonization of superior pole vessels in all patients subjected to thyroid surgery. Intra-operative relationship between the Superior thyroid artery and the External laryngeal nerve was assessed and classied according to Cernea's Classication.The Voice assessment was done both pre operatively and after the surgery by Video Laryngoscopy and EGG (Dr Speech software).The Fundamental frequency of all patients was assessed and compared and documented before & after the surgery by Voice Analysis (EGG). FIG 1 Neck dissection (left) picture showing Superior Laryngeal Nerve along with External Laryngeal Nerve* and Internal Branch of Superior Laryngeal Nerve IBSL, Upper Pole of Thyroid Gland TG ,Superior Thyroid Artery STA FIG 2 Neck dissection (left) picture showing EBSLN* , Upper Pole of Thyroid Gland TG, Upper Pole of Thyroid Gland TG ,Superior Thyroid Artery STA FIG 3 Neck dissection (left) picture showing EBSLN*, Upp er Pole of Thyroid Gland TG ,Superior Thyroid Artery STA SURGICAL ANATOMY OF EXTERNAL LARYNGEAL NERVE IN RELATION TO THYROID SURGERY : OUR EXPERIENCE Original Research Paper Dr Brajendra Baser Professor & HOD (Former) SAIMS Medical College,Indore Director,Akash Hospital Indore ENT Objectives - To Study Surgical Anatomy of External Laryngeal Nerve and it's variation in relation to Thyroid Surgery. Methodology – A Non-randomized prospective Study was conducted in patients undergoing Thyroid surgery in SAIMS, Indore. The ELN was identied and preserved intra operatively. The function of Nerve was assessed and documented by pre op & post op EGG and Video laryngoscopy. Results- Intraoperative identication of ELN leads to almost negligible changes in voice quality. A permanent drop in Fundamental Frequency (Fo) was seen in signicant number of patients when the nerve was not identied during surgery. Conclusion - Today in the era of 21st century where we are reaching new horizons, efforts to further rene thyroid surgery continues. Good range of voice is not only important for Singers but for Teachers, Politicians, RJ, public speakers etc too. An attempt to preserve External Laryngeal Nerve should be done to preserve Voice Quality as an integral part of surgery. ABSTRACT KEYWORDS : External Laryngeal Nerve,Voice Quality, Thyroid Surgery, Superior Thyroid Pedicle, Fundamental Frequency VOLUME-9, ISSUE-3, MARCH-2020 • PRINT ISSN No. 2277 - 8160 • DOI : 10.36106/gjra Dr Vishal Rattan Munjal Prof & HOD SAIMS Medical College,Indore Dr Manya Thakur Roy* Assistant Professor ENT, Pt JNM Medical College Raipur CG ,India *Corresponding Author 48 X GJRA - GLOBAL JOURNAL FOR RESEARCH ANALYSIS SURGICAL TECHNIQUE FIG 4 Keeping close to capsule of gland in the avascular cricothyroid space of Reeve an attempt to identify the nerve by dissecting laterally and at the junction of superior thyr oid pole is made. Capsular dissection, skeletonization and individual ligation of superior pole vessels is carried out to identify and preserve External Laryngeal Nerve. The superior vascular pedicle is clamped and sectioned after 2identication of the superior laryngeal nerve. FIG 5 Intra Operative picture showing EBSLN* and Thyroid Gland with Type I Variation FIG 6 Intra Operative picture of EBSLN*, Thyroid Gland & Superior Thyroid Artery showing Type II variation. FIG 7 Intra Operative picture showing EBSLN* , Thyroid Gland & Superior Thyroid Artery with Type II Variation. FIG 8 Intra Operative picture showing EBSLN, Superior Thyroid Artery and Thyroid Gland with Type III Variation. FIG 9 Intra Operative picture showing EBSLN * & Thyroid Gland with Type IV variation RESULTS Total number of patients who underwent thyroidectomy was 90, Out Of those 22 were males and 68 were females. The Gender Distribution ratio in this study among Male : Female is 1:3.The youngest person in the study group is 19 years old, the oldest person is 68 years old and the mean age is 43.5 years as shown in Table 1 below Table 1 Showing Age wise Distribution Table 2 Showing Type of Nerve according to position with reference to Cernea's Classication. On assessment of Voice by EGG , In 82 patients there was almost negligible changes in Pre Op & Post Op (F ) of voice. In o 8 Patients Permanent Drop of F0 patients was seen in 5 cases where Nerve could not be identied and in 3 patients with Type 2 B variation. In present study the ELN injury was 6.8%. In our study Cernea Type 2a was the most common position followed by Type 2b the Type 1.Several other authors also advocate Cernea Type 2a as the most common position found intraoperatively as mentioned below in Table 3. DISCUSSION The external laryngeal nerve which is a branch of the superior laryngeal nerve, supplies the cricothyroid muscle is not routinely identied by surgeons during thyroidectomy, as it is a very ne nerve and its course is highly variable. Its injury results in loss of the high pitch of the voice and injury to the superior laryngeal nerve results in choking on swallowing food and liquids due to the epiglottic sensation being lost. In order to prevent injury to the nerve, surgeons routinely ligate the superior thyroid artery with its venae comitantes very close to the superior pole of the thyroid without actually identifying or tracing out the nerve course. According to Chosky and Nicholson the nerved can also be stretched and injured by a retractor or transected when the superior thyroid vessels are 6divided. CERNEA ET AL DESCRIBED THE CLASSIFICATION OF THE DIFFERENT TYPES OF ELNS AS FOLLOWS (FIG. 10): Type 1: Nerve crossing the superior thyroid vessels 1 or more cm superior to the apex of the superior thyroid pole Type 2: Nerve crossing the superior thyroid vessels less than 1 cm superior or inferior to the apex of the superior thyroid pole Type 2a: Nerve less than 1 cm superior the apex of the superior thyroid pole, and Type 2b: Nerve inferior to the apex of the superior thyroid pole. Type 2a and 2b nerves are considered to be the ''nerves at an VOLUME-9, ISSUE-3, MARCH-2020 • PRINT ISSN No. 2277 - 8160 • DOI : 10.36106/gjra TYPES VARIATIONS OF THE NERVE Cernea et al Present Study TYPE I CROSSES STA > 1 CM ABOVE UPPER POLE 60% 22.01% TYPE IIa CROSSES STA < 1 CM ABOVE UPPER POLE 17% 49.5% TYPE IIb CROSSES STA UNDER COVER OF UPPER POLE 20.2% 28.4% STUDY TYPE PERCENTAGE PRESENT STUDY TYPE 2A 49.50 % AINA & HASSAN ET ALL3 TYPE 2A 56% SEON-BAE & HYE-YOON ET ALL4 TYPE 2A 58% ANAND MISHRA & HEMA5 TYPE 2A 53.84% X 49GJRA - GLOBAL JOURNAL FOR RESEARCH ANALYSIS increased risk'' of iatrogenic lesion during a thyroidectomy, 7,8owing to their low-lying course Fig. 10 Showing Variation in course of External Laryngeal 9Nerve according to Cernea's classication. The incidence reported in the literatures of injury to EBSLN intraoperatively in thyroid surgery is not very well docum ented as that of the recurrent laryngeal nerve which has been reported to be from 0.3% to 56% earlier.10. In present study the ELN injury was 6.8% In fact, Lennquist et al has described this nerve as the ''neglected'' nerve in thyroid gland surgery, despite the fact that injury to these nerves can also cause signicant 11disability. A full understanding of the anatomy of the superior laryngeal nerve and its branches is necessary for all the head and neck surgeons and could prepare the surgeon to reduce this risk of damage. Especially when the nerve has a variable course as per the Cenea's classication Type 2a and 2b injury can occur easily if not taken care. There are various studies which have suggesterd that nerve could be easily identied by giving few extra minutes,while dissecting the upper pole. According to Mishra AK et al nerves could be identied in 72 (92.31%) out of 78 patients in which superior pole was dissected during 12 thyroidectomy. Pagedar NA et al conducted a study in Canada on 178 patients undergoing thyroidectomy over a period of 4 years only 3 out of 178 nerves (1.7%) could not be 13identied using the routine technique. Aina EN et al conducted a study on the external laryngeal nerve in which total of 202 external laryngeal nerves were identied during 14 thyroid surgery, which was 92.7 %. In present study Out of 117 Nerves at risk 4 could not be identied (3.4%) CONCLUSION Today in the era where advancement in every eld is taking place, efforts to further rene thyroid surgery continues. The voice quality is not only important for singers, speakers or Hawkers but for normal persons too. The aim of the study is not only to treat the disease but also try to improve quality of life after surgery. Injury to the ELN may result in transient loss of high pitched voice but often may lead to permanent change. Patients like Orators, Singers and Teachers who heavily depend on their voices may lose their livelihood. it is possible to identify the external laryngeal nerve with little effort in almost all cases and as in larger number of patients position of nerve comes under high risk. For ELN preservation it is always advisable to Identify and preserve it thus avoiding critical alterations in the voice quality. A permanent drop in fundamental frequency was seen in a signicant number of patients in the cases where nerve was not identied during the surgery. Careful dissection & spending few extra minutes during surgery can render almost near normal voice quality for all the patients. KEY HOME MESSAGE – The author highly recommend Prevention of voice quality for all the patients undergoing Thyroid Surgery and sensitize surgeons about careful dissection and preservation of ELN in each and every case which is often ignored routinely by many surgeons. It is injustice on the surgeon's part to cause a voice change which could have easily been prevented by spending another minute or two on dissection and identication of the nerve. FUNDING: No funding sources CONFLICT OF INTEREST: None declared ETHICAL APPROVAL: The study was approved by the institutional ethics committee ACKNOWLEDGMENTS We are thankful to the Dept of Anatomy SAIMS, Indore for helping us in Cadaver Dissection and studying the Anatomy of Nerve. REFERENCES 1. E N. Aina And A.N. Hisham External Laryngeal Nerve In Thyroid Surgery: Recognition And Surgical Implications;Anz J. Surgery;Volume 71 ; 211- 213;Nov-2001 2. Standring S, Berkovitz Bkb. Thyroid Gland. 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External Laryngeal Nerve In Thyroid Surgery: Recognition And Surgical Implications. Anz J. Surg. 2001;71:212-4 VOLUME-9, ISSUE-3, MARCH-2020 • PRINT ISSN No. 2277 - 8160 • DOI : 10.36106/gjra 50 X GJRA - GLOBAL JOURNAL FOR RESEARCH ANALYSIS