Simultaneous Parathyroidectomy With Total Thyroidectomy Increases Risk of Hypoparathyroidism

Patients receiving a concurrent parathyroidectomy (PTX) undergoing total thyroidectomy (TTX) was linked to an increased risk of immediate and long-term hypoparathyroidism, according to a study published in Journal of Surgical Research.¹ Investigators emphasized that these findings should be considered during the consent discussions and decision-making process.

“TTX is a common elective operation performed for a heterogeneous group of indications, including thyroid cancer, benign multinodular goiter, and hyperthyroidism,” wrote Robin Cisco, MD, Department of Surgery, Stanford University School of Medicine, and colleagues. “Known complications of TTX include recurrent laryngeal nerve injury, neck hematoma, and hypoparathyroidism. A subset of patients presenting for TTX undergo concurrent PTX because of a separate diagnosis of primary hyperparathyroidism. There are limited data on the risk profile of TTX with concurrent PTX (TTX + PTX).”

Results from prior studies found that the risk of complications in patients that underwent TTX increased due to patient characteristics, such as sex and body mass index (BMI), surgeon factors, and thyroid disease characteristics, such as Graves’ Disease.²

The Collaborative Endocrine Surgery Quality Improvement Program (CESQIP) database was used to identify adult patients who underwent TTX or TTX + PTX between January 2014 and April 2020. A multivariable logistic regression predicted hypoparathyroidism, neck hematoma postoperative emergency department visits, and vocal cord dysfunction. Possible covariates included demographics, BMI, central neck dissection, indication for surgery, surgeon volume, and anticoagulation use.

All patients had primary hyperparathyroidism as the indication for PTX. Patients were excluded if they were undergoing thyroid lobectomy, had a diagnosis of secondary and tertiary hyperparathyroidism, incidental PTX, repoerative TTX or PTX, or were missing a number of excised parathyroid glands in the TTX + PTX group.

In total, 13,647 (95.4%) patients underwent TTX and 654 (4.6%) had TTX + PTX. Compared with the TTX group, patients in the TTX + PTX group were older (63 vs 51, P <.001) and had a higher proportion of females (85.3% vs 81.4%, P = .012). Within the TTX + PTX cohort, 63.3% (n = 414) had 1 parathyroid gland removed, 22.3% (n = 146) had 2 glands removed, 8.6% (n = 56) had 3 glands removed, and 5.8% (n = 38) had ≥3 parathyroid glands removed. In the CESQIP cohort, TTX and TTX + PTX were predominantly performed by high-volume surgeons (75.7% and 65.7%, respectively).

The unadjusted rates of hypoparathyroidism were higher in patients who underwent TTX + PTX at 30 days (9.6% vs 7.4%, P = .04) and 6 months (7.9% vs 3.1%, P <.001). Multivariable regression showed that TTX + PTX was linked to an increased risk of hypoparathyroidism at both 30 days (odds ratio [OR] 2.09, 95% confidence interval [CI] 1.57 – 2.79) and 6 months (OR 4.63, 95% CI 3.06 – 7.00). There was also an increased risk of postoperative emergency department visit in this patient population (OR 1.66, 95% CI 1.20 – 2.31). However, TTX + PTX was not associated with recurrent laryngeal nerve injury or neck hematoma.

Investigators noted several limitations, including using retrospective data and that patients undergoing TTX + PTX may have been followed more closely than those undergoing TTX alone. Further, a significant amount of missing data for outcomes at the 6-month follow-up may have introduced bias into the comparison of cohorts. As data was collected via surgeon self-reporting, hypoparathyroidism and vocal cord dysfunction interpretations were up to the discretion of surgeons and institutions.

“TTX + PTX represents a higher risk procedure than TTX alone, with increased rates of transient and prolonged hypoparathyroidism,” investigators concluded. “These findings should inform consent discussions and patient education regarding the expected postoperative course for concurrent TTX + PTX. Intraoperatively, surgeons should proceed with awareness of these risks and should use available adjuncts, including intraoperative parathyroid hormone, which may help guide the extent of the PTX.”

References

1. ^{Cisco R, Arnow K, Barreto N, Lin D, Kebebew E, Seib C. Increased Risk of Complications Associated With Concurrent Parathyroidectomy in Patients Undergoing Total Thyroidectomy [published online ahead of print, 2023 Apr 10]. J Surg Res. 2023;288:275-281. doi:10.1016/j.jss.2023.02.036}
2. ^{Falch C, Hornig J, Senne M, et al. Factors predicting hypocalcemia after total thyroidectomy - a retrospective cohort analysis. Int J Surg. 2018; 55: 46-50}