Impact of body mass index on robotic transaxillary thyroidectomy
Obesity is associated with increased operating times and higher complication rates in many types of surgery. Its impact on robotic thyroidectomy however, is not well documented. The aim of this study was to investigate the relationship between body mass index (BMI) and robotic transaxillary thyroidectomy (RTAT). A retrospective review of prospectively collected data of all patients who underwent RTAT at Yonsei University Health System from October 2007 to December 2014 was performed. Patients were divided into three groups based on BMI (Group 1: BMI < 25, Group 2: BMI 25–29.99, Group 3: BMI ≥ 30), and compared. A total of 3697 patients were analyzed. No differences between the three groups were observed in clinicopathological factors, extent of surgery or length of stay. After multivariate analysis, only seroma and transient voice hoarseness were related to increasing BMI. Total operative time was significantly longer for Group 3 patients with less-than-bilateral total thyroidectomy (BTT), but was not significantly different for patients with BTT. Although obese patients undergoing RTAT have a slightly higher risk of seroma, transient voice hoarseness, and longer operative times, BMI did not influence the other important surgical outcomes of thyroidectomy. Therefore, obesity should not be a contraindication for performing RTAT.
Minimally invasive surgery (MIS) is an increasingly common technique used in most surgical practices because of advantages of smaller incisions, reduced pain, less blood loss, shorter length of hospital stay, and earlier return to work. MIS for cervical endocrine glands began in 1996 when Gagner performed the first endoscopic subtotal parathyroidectomy in a patient with primary hyperparathyroidism1. Subsequently in 1997, Huscher et al. described the first endoscopic right thyroid lobectomy2. Different endoscopic approaches have since been developed and performed worldwide for better cosmesis and avoidance of neck scars. Endoscopic techniques are however limited by rigid instruments that cannot articulate for more precise retraction and dissection of vital structures around the thyroid gland.
Our institution developed gasless, robotic transaxillary thyroidectomy (RTAT) in 20073. Since then, we have performed more than 5000 thyroidectomies using this technique, achieving results that are comparable in complication rates and oncological outcomes to standard open operation4. Some surgeons have, however, been skeptical that such good results are only possible because of favorable patient body habitus, as the Korean population is mostly within the normal BMI range, as opposed to patients from Western countries where the obesity rate is much higher. This difference was highlighted in the 2013–2014 National Health and Nutrition Examination Survey that reported a U.S. obesity rate (BMI ≥ 30 kg/m2) of 40.4% in females and 35.0% in males5. The obesity rate in South Korea as reported by the Korean National Health and Nutrition Examination Survey for the same period, was 4.3% for females and 5.3% for males6.
Despite the significantly lower obesity rate in South Korea, our department still manages a small number of obese patients. Given that few objective data are available on the relationship between obesity and surgical outcomes of patients undergoing RTAT, we, at the largest robotic thyroidectomy center in the world, investigated the impact of BMI on operative time, morbidity and long-term outcomes of RTAT at our institution.