ACCIDENTAL PARATHYROIDECTOMY AS A RISK FACTOR FOR POSTOPERATIVE HYPOCALCEMIA IN THYROID SURGERY P ANAGIOTIS P ALIOGIANNIS 1 , ILIA P ATRIZIA PISANO 1 , ANTONIO MARROSU 1 , FABIO PULIGHE 1 , P AOLA FARA 1 , CARLO BIDDAU 2 , GIOVANNI SOTGIU 3 , MARIO TRIGNANO 1 1 Department of Surgical, Microsurgical and Medical Sciences, University of Sassari - 2 Faculty of Medicine and Surgery, University of Sassari - 3 Epidemiology and Medical Statistics Unit, Department of Biomedical Sciences, University of Sassari – Research, Medical Education and Professional Development Unit, AOU Sassari, Italy Introduction Hypocalcemia is the most incident complica- tion in thyroid surgery (1-4) . It may be temporary, lasting for less than 6 months, or permanent (4) . In both cases, the occurrence of this complication neg- atively impacts the quality of life of patients who underwent total thyroidectomy and the costs for the national health care system. Several risk factors have been proposed to explain the occurrence of postoperative hypocal- cemia in thyroid surgery, like advanced age, female sex, type of surgery, neoplastic disease, technical errors, haemodiluition, hungry bone syndrome, and surgical expertise (2, 4-7) . Inadvertent parathyroidec- tomy is one of the most common adverse events in thyroid surgery; its role in determining postopera- tive hypocalcemia is currently a matter of debate. The aim of this study was to evaluate the role of unintentional parathyroidectomy as a risk factor for postoperative hypocalcemia in patients submitted to total thyroidectomy. Materials and methods The study was conducted on 102 patients who underwent total thyroidectomy in our institution in the last 7 years. Sixteen patients were males and 86 females (male/female ratio: 1/5.4). The mean age of the patients was 55 years (range 16 to 85). Patients with alterations of the metabolism of calcium (endocrinological or other) were excluded from the study. Also patients with extrathyroidal neoplastic Acta Medica Mediterranea, 2014, 30: 91 ABSTRACT Introduction. Hypocalcemia is the most common complication in thyroid surgery. The identification of risk factors is useful to avoid postoperative hypocalcemia and prolonged hospital stay in patients who underwent total thyroidectomy. The aim of this study was to evaluate the impact of accidental parathyroidectomy during thyroidectomy on the postoperative calcemic status of the patients. Materials and Methods. Clinical and pathological data of 102 patients who underwent total thyroidectomy were reviewed. We compared postoperative serum calcium levels of 51 patients without accidental removal of the parathyroids (group A) with those of 51 patients with unintentional parathyroidectomy (group B). Furthermore, calcemic levels were stratified in relation to the number of parathyroids accidentally removed. Results. Biochemical postoperative hypocalcemia was observed in 40 (39%) patients overall: eleven of them belonged to Group A and 29 to Group B. The mean value of postoperative calcemia was 8.5 mg/dL in group A and 7.9 mg/dL in Group B. Patients with one parathyroid excised presented hypocalcemia in 50% of cases, while biochemical hypocalcemia was observed in all patients with more than one gland excised. Conclusions. Our data suggest that unintentional parathyroidectomy during total thyroidectomy increases the incidence of post-operative hypocalcemia. The number of glands accidentally excised influences the incidence rates of postoperative hypocal- cemia. Key words: thyroid, hypocalcemia, thyroidectomy, parathyroids. Received September 14, 2013; Accepted November 30, 2013