Electrosurgical energy. Is it a risk factor for post-thyroidectomy hypocalcaemia?

Aim and objective: The aim of this study was to investigate a relationship between the different types of electrosurgical energy (monopolar, bipolar, and ultrasonic-harmonic scalpel) and postoperative hypocalcaemia after total thyroidectomy. Additionally, to analyze the frequency of postoperative hypocalcaemia, according to age group, gender, and pathological diagnosis. Materials and Methods: An observational, retrospective and correlational study was carried out in a series of patients who underwent total thyroidectomy in a public and a private hospital in Quito, Ecuador, South America, from January 2016 to July 2019. Results: Among 665 patients, post-thyroidectomy hypocalcaemia was observed in 127 (18.8%) patients. There was no significant difference between males and females. Hypocalcaemia was significantly higher in patients aged between 26 and 35 years, patients operated for malignant tumors and in patients in whom at least one parathyroid gland was removed. Postoperative hypocalcaemia occurred in 52.2% of patients (n = 24) [RR: 3.14; 95% CI: 2.26-4.36; p: 0.001] in the bipolar group, 29.2% (n = 7) [RR: 1.56; 95% CI: 0.82-2.97; p: 0.087] in the harmonic group, 17.3% (n = 34) [RR: 0.87; 95% CI: 0.61-1.24; p: 0.219] in the monopolar group, and 15.2% (n= 60) [RR: 0.61; 95% CI 0.45-0.84; p: 0.001] in the monopolar + harmonic group. Conclusions and clinical significance: The use of a bipolar device appears to be a risk factor for hypocalcaemia, while the use of monopolar + harmonic seems to be a protective factor. Although, when analyzing monopolar + harmonic vs monopolar alone, the addition of the harmonic scalpel didn’t provide statistically significant additional protection against hypocalcaemia.