Morbidity and mortality associated with thyroid surgery – retrospective analysis 1991−2010

Introduction: The incidence of thyroid disorders has been rising worldwide. Unlike the incidence, mortality associated with malignant thyroid cancer shows only a modest increase. Between 1979 and 2009, mortality in Czech women increased from 1.21 to 1.31 and in Czech men from 0.54 to 0.74 cases per 100,000 individuals. Methods: A retrospective statistical analysis was performed in patients undergoing thyroid surgery at the Department of Otorhinolaryngology and Head and Neck Surgery of the 1st Faculty of Medicine, Charles University and University Hospital Motol, and at the Department of Otorhinolaryngology of the Institute for Postgraduate Medical Education in Prague from 1991 to 2010 (twenty years). In this period, 11,005 procedures were done for thyroid disease. The study analysed the incidence, morbidity, mortality, surgical complications and lethality. Results: The study group included surgeries in 1588 male and 9417 female patients. The male/female ratio was 1:5.93. Benign thyroid tumours – mean patient age is 54.7 years; recurrent nerve morbidity is 1.37% (calculated from exposed nerves). Hypocalcaemia incidence is low, 5.4% of permanent hypocalcaemia or hypoparathyroidism, respectively, based on decreased serum parathyroid hormone (PTH) levels. Temporary hypocalcaemia is much more frequent, occurring in almost 15% cases depending on age, season of the year, and nutritional status. Hypoparathyroidism was demonstrated based on laboratory serum PTH levels only in 0.3% patients. In total, 442 patients were operated for the mechanic syndrome (a large goitre). The mean thyroid volume was 493 ml±136 ml; however, the maximum volume was 980 ml and weight 1115 g. The incidence of recurrent nerve injury occurs in 4.5%, i.e. the morbidity is 2 times higher compared to surgeries for other diagnoses. The incidence of hypoparathyroidism is not higher compared to other surgeries. Revision surgeries were indicated more commonly in malignant thyroid diseases, particularly in papillary and follicular carcinomas. Cervical lymph nodes procedures comprise another large segment in tumour treatment. Our analysis supports selective neck dissections while preserving non-lymphatic structures. As a rule, mortality associated with thyroid surgery is divided as mortality in the perioperative period (within 24 hours after the procedure) and early postoperative mortality (within 120 hours after the procedure). Surgery-related mortality was never classified as perioperative or within 24 hours after the procedure. Despite that, we believe that perioperative mortality within 120 hours after the procedure, which occurred in 7 cases, is very important. Mortality of the group was 0.007%. Conclusions: Each surgery procedure is associated with complications, morbidity and mortality. Experience of endocrine surgeons of all disciplines leads to a very low incidence of recurrent nerve and parathyroid gland injuries while at the same time achieving sufficient radicality. This, in cooperation with other medical fields such as endocrinologists, nuclear medicine specialists and oncologists, supports a safe and effective management of all thyroid disorders, including a good prognosis of patients with most types of cancer.