Applicability of intraoperative parathyroid hormone assay during total thyroidectomy as a guide for the surgeon to selective par

Abstract
Background  Intraoperative parathyroid hormone assay (IOPTH) has been suggested to have value in predicting the development of postoperative
hypoparathyroidism after thyroid surgery. IOPTH has been validated in identification of patients at risk of postoperative
hypocalcemia requiring early onset of calcium supplementation therapy and in improving selection of patients eligible for
a safe early discharge. However, the value of IOPTH has not been assessed in a randomized study as a guide for the surgeon
to parathyroid tissue autotransplantation (PA). The objective of this study was to evaluate the applicability of IOPTH in
guiding the surgeon to selective parathyroid tissue autotransplantation during total thyroidectomy (TT).

Methods  Between January 2005 and December 2005, 340 patients qualified for total thyroidectomy (TT) who met the inclusion criteria
were randomized to two equal-sized groups (n = 170): group A, in which elective PA of at least one parathyroid gland was performed
in all cases without IOPTH as a guide; and group B, in which selective IOPTH-guided PA was performed, if only the iPTH plasma
level was <10 ng/L at 10–20 min after TT (before skin closure). The standard technique of PA consisting of implanting the
parathyroid tissue into 10–20 sternocleidomastoid muscle pockets was used in both groups. IOPTH measurements were performed
by the STAT-Intraoperative-iPTH-Assay. Serum calcium was routinely monitored at 4, 12, 24, 48, and 72 hr postoperatively.
The incidence and severity of hypocalcemia and related symptoms were matched with the IOPTH results. On follow-up, serum calcium
and plasma iPTH values were measured at 1, 3, and 6 months postoperatively. The primary end point was the success rate in
preventing permanent postoperative hypoparathyroidism. The secondary end point was the use of postoperative medication for
transient hypocalcemic symptoms.

Results  Twenty-one group B patients (12.3%) had plasma iPTH levels <10 ng/L at 10–20 min after TT (before skin closure) and they underwent
selective IOPTH-guided PA. None of the patients from both groups experienced permanent postoperative hypoparathyroidism. Transient
postoperative hypocalcemia occurred in 22.3% vs. 11.2% of patients (group A vs. B, respectively; p < 0.05). The mean cumulated serum calcium values were significantly lower for group A vs. group B patients within the entire
3-month period after TT (2.12 ± 0.09 mmol/L vs. 2.27 ± 0.05 mmol/L, respectively; p < 0.001). The mean oral calcium supplementation was significantly higher for group A vs. group B patients during the 3 months
after TT (2.7 ± 0.9 g/day vs. 0.9 ± 0.4 g/day, respectively; p < 0.001).

Conclusions  IOPTH offers valuable information during TT, correctly identifying patients at risk of postoperative hypocalcemia. Selective
IOPTH-guided PA in patients with plasma iPTH levels <10 ng/L at 10–20 min after TT reduces the risk of permanent postoperative
hypoparathyroidism to zero, and this approach seems to be as effective as elective PA of at least one parathyroid gland without
IOPTH guidance. Moreover, selective IOPTH-guided PA significantly decreases the incidence of transient postoperative hypoparathyroidism
and the need for calcium supplementation therapy compared with elective PA without IOPTH.

Content Type Journal ArticleDOI 10.1007/s00268-007-9405-8Authors
Marcin Barczyński, Jagiellonian University College of Medicine Department of Endocrine Surgery 37 Prądnicka Street 31-202 Kraków PolandStanisław Cichoń, Jagiellonian University College of Medicine Department of Endocrine Surgery 37 Prądnicka Street 31-202 Kraków PolandAleksander Konturek, Jagiellonian University College of Medicine Department of Endocrine Surgery 37 Prądnicka Street 31-202 Kraków PolandWojciech Cichoń, Jagiellonian University College of Medicine Department of Endocrine Surgery 37 Prądnicka Street 31-202 Kraków Poland

Journal World Journal of SurgeryOnline ISSN 1432-2323Print ISSN 0364-2313 (Source: World Journal of Surgery)