Post-thyroidectomy hypoparathyroidism, what should we keep in mind?

Abstract

AIM: Hypoparathyroidism and the resulting hypocalcemia is a common iatrogenic complication following surgical procedures to the neck, and commonly, to the thyroid gland. The aim of this study was to review the available literature to summarize current data related to the development of hypoparathyroidism after thyroid surgery.

MATERIALS AND METHODS: An analysis of the surgical literature was performed using the search engine EMBASE and PubMed with particular reference to the principal risk factors related to the post-thyroid surgery hypoparathyroidism. Moreover the medical records of 345 patients, who underwent thyroid surgery at the Section of Endocrine Surgery Department of Medical and Surgical Sciences, Advanced Technologies “G. Ingrassia” University of Catania, Italy, were also examined.

RESULTS: The definition of hypoparathyroidism varies widely in literature. There is a wide range of reported incidences of transient and permanent postoperative hypoparathyroidism in literature. Extensive surgery, malignant disease and concomitant central and/or lateral neck dissection, autoimmune or Grave’s’ disease and re-operation represent the most recognized risk factors. A wide consensus exists about transplanting a parathyroid gland when it seems to be nonviable.

DISCUSSION: Although many improvements have been done in surgical technique, hypoparathyroidism seems to be one of the most common complication after total thyroidectomy. In this study we discuss the diagnosis methods and the importance of its early prediction regardless it is transient or permanent. Recovery time is under discussion: some author consider a gland permanent injury if restoring functionality does not occur within 6 months other 12 months. To assess the parathyroid gland function some authors have been using postoperative PTH level as a useful tool for predicting hypocalcemia.

CONCLUSIONS: Many efforts are required to address the problem of a consensus on best define these complications. An early low PTH level after total thyroidectomy is associated with a high risk of permanent hypoparathyroidism and normal levels usually exclude long-term parathyroid glands dysfunction. However, the cost of the PTH assay may limit its widespread application. Despite the reassuring presence of new therapeutic strategies, intra-operative preservation of the parathyroid glands is the best prophylaxis to avoid postoperative hypocalcemia after total thyroidectomy.