Minimally Invasive Parathyroidectomy for Primary Hyperparathyroidism - Current Views, Issues and Controversies

Abstract

Although primary hyperparathyroidism (pHPT) remains a relatively uncommon endocrine disease in Asian countries with an incidence ranging from 17 to 33 / 100,000 cases per year, it has been increasing over the last decade. (Bilezikian et al. 2000; Lo et al. 2004; Chen et al., 2010) In contrast, in the Western world, pHPT is a relatively more common disease with an estimated incidence of 42 to 190/100,000 cases per year. Surgical treatment or parathyroidectomy remains the only curative therapy for patients with pHPT. The goal of surgery is to normalize postoperative calcium levels by excising all hyperfunctioning parathyroid tissue. Traditionally, this has been achieved by way of bilateral neck exploration (BNE) which involves examination of all four parathyroid glands and excision of any enlarged glands. However, with improvement in preoperative localization techniques and the commercial availability of quick intraoperative parathyroid hormone assay (IOPTH), an increasing number of endocrine surgeons are now performing minimally invasive parathyroidectomy (MIP). In experienced hands, many studies have found that MIP is not only a less invasive procedure associated with shorter hospital stay and less pain but also can achieve similar long-term cure rate of up to 95-98% as BNE which many would still regard it as the gold standard procedure. With this in mind, the purpose of this review is to look at the current views, issues and controversies associated with the use of preoperative localization studies, IOPTH and various surgical techniques of MIP by a comprehensive MEDLINE search using several specific keywords. These keywords include “minimally invasive parathyroidectomy”, “focused parathyroidectomy”, “intraoperative parathyroid hormone” and “parathyroid adenoma”. Since the success of MIP depends partly on the accuracy of preoperative localization studies and IOPTH, it is imperative to assess them in an evidence-based method. The review would look specifically on the use of 99mTc Sestamibi (MIBI) and high-resolution ultrasound (USG) as both modalities are the most commonly employed and accurate imaging before MIP. The review would also look at the issues when there are concordant and discordant results between the MIBI and USG as well as examine the role of surgeon-performed USG (SPUS) in pHPT. Regarding the IOPTH, it remains controversial whether it should be routinely used in all cases of pHPT as some still question the cost-benefit and the “added value” of this particular operative adjunct.