Association between neck hematoma and postoperative hypocalcemia: Analysis of 53,091 thyroidectomies from the American College of Surgeons-National Surgical Quality Improvement Program database.

BACKGROUND: Neck hematoma and hypocalcemia are among the most significant complications after thyroidectomy, but their relationship remains unclear. We hypothesized that post-thyroidectomy neck hematoma is associated with an increased risk of postoperative hypocalcemia. We aimed to test this hypothesis using a large national cohort and identify high-risk patients. METHODS: We performed a retrospective cohort analysis of thyroidectomy patients using the American College of Surgeons-National Surgical Quality Improvement Program database (2016-2023). The primary exposure was postoperative neck hematoma, and outcomes included multiple hypocalcemia metrics. Associations were evaluated using the χ2 test or the Fisher exact test and multivariable logistic regression. RESULTS: Among 53,091 thyroidectomy patients, most patients were female (76.8%) and White (70.2%), with a median age of 53 years (interquartile range, 40-64). Most cases were performed for a solitary nodule (N = 20,894, 40.6%). Postoperative hematoma complicated 916 (1.7%) cases, of which 223 (24.3%) were managed nonoperatively. The hematoma cohort exhibited a higher frequency of Graves' disease (10.2% vs 6.7%, P < .001). Hematoma patients had higher rates of all hypocalcemia metrics, including hypocalcemia before discharge (6.6% vs 3.7%, P < .001) and severe hypocalcemia events (5.2% vs 3.3%, P = .005). These associations persisted even for hematomas managed nonoperatively. Among nonreoperative open thyroidectomies without neck dissection (n = 22,157), similar results were observed: for example, hypocalcemia before discharge (6.0% vs 2.8%, P < .001) and severe hypocalcemia events (6.5% vs 2.8%, P < .001). Findings were more pronounced among Graves' disease patients (eg, intravenous calcium requirement 16.2% vs 5.8%, P < .001). CONCLUSION: Post-thyroidectomy neck hematoma is associated with an increased risk of hypocalcemia-related complications even when managed nonoperatively. This suggests a possible pathophysiologic mechanism such as hematoma-induced parathyroid ischemia or venous congestion. Proactive calcium monitoring and supplementation are warranted in patients developing postoperative hematoma. Further studies are needed to elucidate the underlying pathophysiology.