Study of the variation in the relations of recurrent laryngeal nerve to the thyroid gland and its vascular pedicles

Thilagavathi, J (2009) Study of the variation in the relations of recurrent laryngeal nerve to the thyroid gland and its vascular pedicles. Masters thesis, Stanley Medical College, Chennai.

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Abstract

AIM OF THE STUDY: A sound knowledge of the normal human anatomy and common variations in it are very important to a physician and gives a major contribution to the skill and success of a surgeon. This is especially true for a surgeon, operating on the neck because it is one of the most difficult areas to operate upon, there being a very little space. The recurrent laryngeal nerve innervates the intrinsic muscles of the larynx. These muscles are important in the production and modulation of the phonation component of the voice. During the course of the recurrent laryngeal nerve in the neck, the nerve is intimately related to the inferior thyroid artery and its branches. The relation of the recurrent laryngeal nerve to the inferior thyroid artery and its branches is highly variable. This makes the recurrent laryngeal nerve, extremely vulnerable to injury during the surgical manipulation of the neck, especially in the surgeries involving the thyroid gland. MATERIALS AND METHODS: The study materials are a) 20 cadavers, b) 15 post mortem en-bloc specimens, c) 10 patients who underwent partial or total thyroidectomies, d) 5 still born fetuses. A) DISSECTION ROOM CADAVERS: All the 20 cadavers (12 males and 8 females) had been embalmed with 10% formalin solution containing 4% formalin for 3 months, prior to dissection. B) POST MORTEM EN-BLOC SPECIMENS: 15 post mortem en-bloc specimens (13 males and 2 females) were collected from the Institute of Forensic Medicine, Government Stanley medical college and studied by conventional dissection method. C) CLINICAL STUDY: Subjects included 10 patients; all females, who underwent partial or total thyroidectomies in the surgical operation theatre, Department of surgery, Government Stanley medical college, Chennai. D) Foetal study: 5 still born fetuses (2 males and 3 females) were obtained from the Department of Obstetrics and Gynaecology, RSRM Hospital, Government Stanley Medical College, Chennai. All were embalmed with 10% formalin solution and studied. METHODS: 1. DISSECTION METHOD: The dissection was carried out according to the methodology prescribed in the Cunningham’s Practical Manual. The skin was incised by a vertical incision extending from the symphysis menti to the supra sternal notch. The incision was extended laterally along the lower border of the base of the mandible up to the angle of the mandible. Two triangular laps were reflected on both sides up to the anterior border of the Sternocleidomastoid muscle. The superficial fascia with Platysma was incised and reflected along the line of the skin incision, after noting the position of the anterior jugular veins. The investing layer of the deep cervical fascia was then lifted up using a forceps and incised vertically. It was followed laterally up to its fusion with the Carotid sheath deep to the Sternocleidomastoid muscle on either side. The Sternothyroid and the superior belly of the omohyoid were cleared from their fascial covering. Their nerve supply from the Ansa cervicalis, entering their lateral border was noted. They were then divided in the middle 1/3rd just distal to their nerve supply and reflected. The Sternothyroid muscle was then exposed and carefully incised in the middle one third and was reflected. This exposed the pretracheal fascia and the thyroid gland. 2. CLINICAL STUDY: The steps of the partial and total thyroidectomies were observed on 10 patients in the surgical theatre. The following parameters of the recurrent laryngeal nerve were noted a. Relation to the tracheo oesophageal groove. b. Relation to the inferior thyroid artery and its branches. 3. FOETAL STUDY: All the still born fetuses were dissected in the anterior triangle of the neck. An attempt was made to identify the recurrent laryngeal nerves on both sides and to study them in relation to the same parameters as that mentioned for adult specimens. CONCLUSION: In the present study, the anatomy of the recurrent laryngeal nerve has been analyzed under the parameters described by the eminent authors in the field of Anatomy. Analysis of the recurrent laryngeal nerve was done separately on both sides of the neck and in both the sexes. The recurrent laryngeal nerve has been analyzed based on its origin, course and the intimate relationship with the inferior thyroid artery and its branches. The dissection findings of cadavers, post mortem specimens and fetuses have been supported by the clinical studies. The results of the present study have coincided with many of the previous eminent authors. The present study has also mentioned the vulnerable and high risk positions of the recurrent laryngeal nerve and the reasons for the same in the surgical point of view. It is sincerely hoped that the results of the present study will be a guide and will be of great help to the surgeons performing partial and total thyroidectomies.

Item Type: Thesis (Masters)
Uncontrolled Keywords: recurrent laryngeal nerve, thyroid gland, vascular pedicles.
Subjects: MEDICAL > Anatomy
Depositing User: Subramani R
Date Deposited: 05 Oct 2019 06:48
Last Modified: 05 Oct 2019 06:48
URI: http://repository-tnmgrmu.ac.in/id/eprint/11681

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