Novel Parathyroidectomy Procedure May Result in Durably Low PTH
The surgery targets microparathyroid tissues and cells that might exist in unexpected areas.
Purge parathyroidectomy (PTx) may represent a new option in the treatment of secondary hyperparathyroidism (SHPT) refractory to medical therapy.
Nine patients were successfully treated with purge PTx, Cheng-Xiang Shan, MD, Nian-Cun Qiu, MD, and Si-Luo Zha, MD, of Chang Zheng Hospital in Shanghai, China, and colleagues reported in the International Journal of Surgery. High sustained parathyroid hormone (PTH) levels (1062–2879 pg/mL) fell to between 12.35 and 72.69 pg/mL the day after surgery. Some of these PTH values were below a guideline-recommended target of 60 to 180 pg/mL. However, based on a 2016 study by Iwamoto, et al. (Clin Exp Nephrol 20(5);808e814), the investigators suggested that PTH concentrations even below 16.6 pg/mL may reduce cardiovascular deaths.
The operation was performed in 95 to 135 minutes, with blood loss of 20 to 40 mL. No patients died during the procedure or experienced major bleeding. Care was taken by the surgeon to protect the recurrent laryngeal nerve; no injuries ensued.
According to background information, about 2% to 20% of SHPT patients experience recurrent or persistent SHPT within 2 years of conventional PTx procedures, including total PTx, likely due to residual parathyroid tissue. The investigators proposed that microparathyroid tissues and cells could exist in odd places and escape detection, contributing to high PTH after surgery.
Purge PTx was designed to eliminate these invisible “seeds” by removing their “soil.” The procedure removes more than the main PTH glands. According to the team, it involves a comprehensive resection of cervical fibrofatty tissues within the region surrounded by the thyroid cartilage, bilateral carotid artery sheath, and the brachiocephalic artery.
Pathology reports showed that 3 patients in the current study had ectopic parathyroid tissues in areas unknown to contain such cells. Overall, the surgeons resected 37 parathyroid glands from the 9 patients.
None of the patients experienced SHPT recurrence or persistence during the short follow-up period. Patients also did not report severe hypocalcemia symptoms. Patients were closely monitored and received appropriate therapies to avoid low calcium levels.
“Therefore, compared with quantitative removal of parathyroid glands at first surgery and the potential difficulty of a secondary operation for recurrent or persistent SHPT, it is perhaps better for surgeons to remove the cervical ‘parathyroid primordia' completely and convert to a peripheral superficial parathyroid tissue-regulated system thereafter, for example using PPTX with muscular or subcutaneous auto-implantation,” Dr Shan and colleagues stated.
The investigators noted that “it is impossible to remove supernumerary or ectopic glands above the superior parathyroid or below the thymus ligule,” so SHPT relapse remains a possibility after purge PTx.
Shan CD, Qiu NC, Zha SL, et al. A novel surgical strategy for secondary hyperparathyroidism: Purge Parathyroidectomy. Int J Surg. doi: 10.1016/j.ijsu.2017.05.062