AAES GUIDELINES 5: INTRAOPERATIVE PTH MONITORING (IPM)
RECOMMENDATION: When image-guided focused parathyroidectomy is planned, IPM is suggested to avoid higher operative failure rates.
COMMENT: The routine use of intraoperative PTH (IOPTH) monitoring (or IPM )is an area where there is a major difference in practice between the USA and other parts of the world including Britain, Australia and Sweden. Measuring the PTH drop during the operation was developed in the USA and has become widely adopted in that country, now forming part of the guidelines. Studies published from Australia and England however have shown that, with careful selection of patients for minimally invasive parathyroidectomy, based upon high quality concordant pre-operative localisation, the routine use of IOPTH monitoring only increases the success rate by 1%, (from 98% to 99%) and that it is unnecessary for the vast majority of patients. Moreover it is expensive, it increases the time under the anaesthetic and, most importantly, is associated with a false positive rate of between 6 to 9%, meaning that approximately 1 in 10 patients will go on to have an open four gland parathyroid exploration when the IOPTH does not drop, despite already being cured. The authors of the guidelines do state that “ in well-localized patients IPM marginally increases the cure rate of focused parathyroidectomy performed without IPM guidance and incurs approximately 4% higher costs” and that “image guided parathyroidectomy may still be acceptable” In Australia no major unit routinely uses IOPTH monitoring, and published national results are the equivalent of those from the USA. It is important however for patients to be aware that, with or without IOPTH monitorin,g there is a small risk of failure and the need for a second operation after any parathyroidectomy.