Incremental value and clinical impact of neck sonography for primary hyperparathyroidism: a risk-adjusted analysis

Background Despite the different preoperative imaging modalities available for parathyroid adenoma localization, there is currently no uniform consensus on the most appropriate preoperative imaging algorithm that should be routinely followed prior to the surgical management of primary hyperparathyroidism (PHPT). We sought to determine the incremental value of adding neck ultrasonography to scintigraphy-based imaging tests. Methods In a single institution, surgically naive patients with PHPT underwent the following localization studies before parathyroidectomy: 1) Tc-99m sestamibi imaging with single photon emission computed tomography/computed tomography (SPECT/CT) or Tc-99m sestamibi imaging with SPECT alone, or 2) ultrasonography in addition to those tests. We retrospectively collected data and performed a multivariate analysis comparing group I (single study) to group II (addition of ultrasonography) and risk of bilateral (BNE) compared with unilateral (UNE) neck exploration. Results Our study included 208 patients. Group II had 0.45 times the odds of BNE versus UNE compared with group I (unadjusted odds ratio [OR] 0.45, 95% confidence interval [CI] 0.25-0.81, p = 0.008). When adjusting for patient age, sex, preoperative calcium level, use of intraoperative PTH monitoring, preoperative PTH level, adenoma size, and number of abnormal parathyroid glands, Group II had 0.48 times the odds of BNE versus UNE compared with group I (adjusted OR 0.48, 95% CI 0.23-1.03, p = 0.06). In a subgroup analysis, only the addition of ultrasonography to SPECT decreased the risk of undergoing BNE compared with SPECT alone (unadjusted OR 0.40, 95% CI 0.19-0.84, p = 0.015; adjusted OR 0.38, 95% CI 0.15-0.96, p = 0.043). Conclusion The addition of ultrasonography to SPECT, but not to SPECT/CT, has incremental value in decreasing the extent of surgery during parathyroidectomy, even after adjusting for multiple confounding factors.