Factors affecting postoperative hypocalcemia after thyroid surgery: Importance of incidental parathyroidectomy

Abstract

OBJECTIVE:The present study evaluated effects of incidental parathyroidectomy, surgical technique, and presence of thyroiditis or hyperthyroidism on occurrence of postoperative persistent or transient hypocalcemia.METHODS:Patients who underwent thyroidectomy at İstanbul Medeniyet University between 2013 and 2015 were included in the study. Patient information, postoperative serum calcium levels, and pathology reports were investigated retrospectively. Group 1 was made up of patients who were found to have hypocalcemia (calcium ≤8.5 mg/dL) according to postoperative serum level and normocalcemic patients were placed in Group 2. Groups were compared statistically in terms of rate of incidental parathyroidectomy, surgical technique, and presence of thyroiditis or hyperthyroidism.RESULTS:Mean age was 49.8±12.8 years (range: 20-88). A total of 417 patients were included in the study, 74 (17.7%) were male and 343 (82.3%) were female. Group 1 consisted of 205 (49.2%) patients who had hypocalcemia according to postoperative serum level, and remaining 212 (50.8%) patients were placed in Group 2. In Group 1, 38 (18.5%) patients had incidental parathyroidectomy, and with only 18 (8.5%) patients in Group 2, a statistically significant relationship was found between incidental parathyroidectomy and hypocalcemia (p=0.003). There was no statistically significant difference in terms of presence of thyroiditis or hyperthyroidism between groups. There was statistically significant decrease in postoperative hypocalcemia rate in patients with lobectomy compared to patients with bilateral total thyroidectomy or central neck dissection (p<0.01).CONCLUSION:Risk of postoperative hypocalcemia may be reduced with lobectomy for selected patients. In addition, delicate dissection during thyroidectomy is important in order to protect parathyroid glands and prevent hypocalcemia.

Postoperative hypocalcemia: analysis of factors influencing early hypocalcemia development following thyroid surgery

“…In literature hyperthyroidism is described as a risk factor for EH development; it is unclear why thyrotoxic thyroidectomies have an increased rate of hypocalcemia; however, it is perhaps unsurprising as the thyroid gland in thyrotoxicosis tends to be larger than normal and very highly vascularised leading to a more challenging operation [1,29]. In our study thyroid hyperfuntion didn't appear as a significant factor in EH development (Table 2) as confirmed by other studies in literature [9,30].…”

“…include post-operative alkalosis-induced hypocalcemia resulting from hyperventilation triggered by postoperative pain, and diluition hypocalcemia [9].…”

Prospective study of postoperative hypocalcemia after total thyroidectomy

“…Secondary to reduction in parathyroid hormone secretion, mobilization of calcium from bones is impaired, resorption of calcium from distal nephron is reduced and stimulation of renal 1-alpha hydroxylase activity is affected, thus causing hypocalcemia. There is a varied incidence of hypocalcemia, with transcient hypocalcemia incidence ranging from 6.9% to 49%, and permanent hypocalcemia incidence between 0.4% to 33% following total thyroidectomy [8,9,10]. Surgery involving neck dissection in case of thyroid malignancies, reoperation for other benign thyroid disorders increases the risk of parathyroid injury…”

Effect of nerve monitoring on complications of thyroid surgery

“…Hypocalcemia is the most frequent complication of thyroidectomy. The most important factors influencing postoperative development of hypocalcemia include intraoperative trauma to parathyroid gland or its vasculature, inability to identify parathyroid gland during operation, incidental parathyroidectomy, central dissection, bilateral thyroidectomy, and inadequate experience of the surgeon [ 6 , 16 , 28 ]. Luo et al [ 30 ] described symptomatic hypocalcemia as specific numbness, spasm, muscular cramp, and Chevok’s syndrome.…”

“…Again, in this study, the incidence of biochemical hypocalcemia was 26.97% and symptomatic hypocalcemia was 12.5%. The rates of temporary and permanent hypocalcemia in the literature are widely distributed with 1.6%-50% and 0.7%-4.8%, respectively [ 6 , 16 , 28 , 29 ]. These widely-distributed prevalence of hypocalcemia is mostly related with uncertainty on the definition of hypocalcemia, different dissection technique, and variations in calcium and vitamin D replacement treatment plan [ 30 ].…”