Risk factors and outcomes of incidental parathyroidectomy in thyroidectomy: A systematic review and meta-analysis

Abstract

IntroductionPostoperative hypocalcemia is the most common complication of thyroidectomy. Incidental parathyroidectomy (IP) was thought to be associated with postoperative hypocalcemia. However, according to previous studies, the risk factors and clinical outcomes of IP remain controversial.MethodsEligible studies were searched in databases including PubMed, Web of Science, and EMBASE from January 1990 to September 2017. Articles focusing on the relationship between IP and postoperative hypocalcemia were included. The risk of publication bias was assessed using Begg’s test and Egger’s regression asymmetry test. Pooled analysis was performed to evaluate the effect of IP on postoperative hypocalcemia and related risk factors. Sensitivity analysis was also conducted to test the stability of our results. The effects of hypocalcemia type, permanent definition, IP incidence, total thyroidectomy, and malignancy operation were also examined using a further subgroup analysis.ResultsThirty-five studies were finally included in the analysis after an exhaustive literature review. Pathology data demonstrate that incidental parathyroidectomy occurred in various locations: intrathyroidal (2.2–50.0%), intracapsular (16.7–40.0%) and extracapsular (15.7–81.1%) regions. Overall, the analysis found that malignancy (RR = 1.60, 95% CI: 1.27 to 2.02; p< 0.0001), central neck dissection (RR = 2.35, 95% CI: 1.47 to 3.75; p = 0.0004), total thyroidectomy (RR = 1.42, 95% CI: 1.20 to 1.67; p< 0.0001) and reoperation (RR = 1.81, 95% CI: 1.20 to 2.75; p = 0.005) were significant risk factors of IP in thyroid surgery. There was an obvious effect of IP on temporary/permanent (RR = 1.59, 95% CI: 1.37 to 1.84; p< 0.0001) and permanent (RD = 0.0220, 95% CI: 0.0069 to 0.0370; p = 0.0042) postoperative hypocalcemia. Sensitivity analysis showed that these results were robust. The subgroup analysis found that IP played a significant role in both biochemical and clinical hypocalcemia in thyroidectomy (p < 0.0001 and p = 0.0003, separately). The association of IP and permanent hypocalcemia using different definitions (6 months or more than 12 months) was also confirmed by the analysis. IP increased the incidence of temporary/permanent and permanent hypocalcemia for cases undergoing total thyroidectomy (40.4% vs 24.8% and 5.8% vs 1.4%, respectively). Thyroidectomy with IP was associated with more permanent hypocalcemia (RR = 3.10, 95% CI: 2.01 to 4.78; p< 0.0001) in malignant cases but was not associated with temporary/permanent hypocalcemia.ConclusionsMalignancy, central neck dissection, total thyroidectomy and reoperation were found to be significant risk factors of IP. IP increases the risk of postoperative hypocalcemia after thyroidectomy. We recommend a more meticulous intraoperative identification of parathyroid gland in thyroidectomy to reduce IP, particularly for total thyroidectomy and malignancy cases.

Post-thyroidectomy Hypocalcemia - Risk Factors and Management

“…Thus the routine use of calcium and vitamin D in early post-operatory period of time is recommended. This combination is useful for both transitory and permanent hypothyroidism (34).…”

Risk Factors of Incidental Parathyroidecomy in Thyroid Surgery

“…Thyroidectomy is a common, relatively safe surgical procedure, which is associated with <5% morbidity rate [1]. The main postoperative complications of thyroidectomy include injury to the parathyroid glands and recurrent laryngeal nerves.…”

“…Because of its small size and close proximity to the thyroid tissue, inadvertent injury to the parathyroid glands by devascularization and accidental resection are inevitable, which most often can result in symptomatic hypoparathyroidism and hypocalcemia [2,3]. Hypocalcemia could either be transient or 1 2 3 4 5 6 1 permanent. While the reported incidence of the transient hypocalcemia ranges between 10% and 46%, the permanent one ranges between 1.5% and 4% [4].…”

Risk factors of hypoparathyroidism after bilateral total thyroidectomy

“…Low PTH levels at postoperative period are known to be a risk factor for developing hypocalcemia. HPP may develop as a result of dissection of parathyroid glands, malignancy, ligation of the thyroidal arteries remote from the thyroid gland, or inadvertent excision of the parathyroid glands [11,12]. Our study demonstrated a link between inadvertent parathyroid gland excision and developing hypocalcemia.…”