Predictive factors for recurrent laryngeal nerve palsy and hypoparathyroidisirn after thyroid surgery

Objectives: To evaluate the incidence and risk factors of recurrent laryngeal nerve palsy and hypoparathyroidism following thyroidectomy. Design: Retrospective case-control study. Setting: Tertiary clinic. Participants: From September 1990 to September 2005, 3250 consecutive patients who had a thyroidectomy for treatment of various thyroid diseases. Main outcome measures: The rates of nerve palsy and hypoparathyroidism were evaluated based on thyroid pathology, the choice of operative procedure, whether the nerve was identified, and the experience of the surgeon. Results: Overall, the rate of nerve palsy was 1.8% and that of hypoparathyroidism was 6.6%. On univariate analysis the rates of complications were siginificantly higher in the patients who had an extended thyroidectomy, identification of the recurrent laryngeal nerve during surgery, repeat surgery and patients older than 50 years of age. Complications were no commoner in operations performed by trainees under supervision than experienced surgeons. On multivariate analysis extended thyroidectomy had a 12 fold (95% CI 1.7, 92) increased risk of nerve palsy. Repeat surgery had a 3 fold (95% CI 2.1, 4.7) increased risk of postoperative hypoparathyroidism. Conclusion: Extentended thyroidectomy and repeat surgery had a significant effect on the incidence of recurrent laryngeal nerve palsy and postoperative hyperparathyroidism respectively following thyroid surgery.