Prevalence and implications of thyroid related embryological remnants: A prospective study of 1118 total thyroidectomies

Context: Modern thyroid surgery has undergone a paradigm shift from subtotal thyroidectomy to an extended total thyroidectomy (TT) even for benign disorders. This entails removal of all embryological remnants even in benign disorders.

Aims: To study the prevalence of various embryological remnants of the thyroid and surgical utility and implications in preventing complications.

Settings and design: Retrospective study of total thyroidectomies done by a single endocrine surgeon by standardized technique.

Methods and material: A detailed search of all embryological rests including Pyramidal tract (PT), Tubercle of Zuckerkandl (TZ), and Thyro-thymic thyroid rests (TTR) were done in 1118 patients undergoing TT over 6 years. The cases with and without TTR were divided as Group A and B, respectively. Their prevalence and impact on parathyroid preservation and other clinical parameters were analysed.

Statistical analysis used: Descriptive analyses.

Results: Out of the 1118 TT cases, TTR was seen in 230 (20.57%) cases, TZ in 598 (53.48%), cases and PT in 641 (57.33%) cases. Among group-A (n = 230), 213 had unilateral and 17 had bilateral TTR with 51 (22.17%) having retrosternal extension. Compressive symptoms, presence of TZ and PT were also significantly higher in group A. On follow up the incidence of temporary hypoparathyroidism was significantly higher in group-A, where as permanent hypoparathyroidism, temporary and permanent vocal cord palsy were comparable between the two study groups.

Conclusions: Embryological remnants related to thyroid are not uncommonly encountered during total thyroidectomy. A thorough search and complete removal is crucial for the successful outcome of the procedure.