Thyroidectomy is the most performed operation in endocrine surgery. It is widely utilized for the treatment of both benign and malignant thyroid diseases. Over 34,000 operations were performed in Italy during 2016 [20].
Although mortality due to this surgical procedure is negligible, morbidity remains a challenging problem, even in the most experienced hands. In this kind of surgery, morbidity is mainly represented by recurrent laryngeal nerve injury, hypoparathyroidism and cervical haematoma [21,22,23,24,25].
The correct positioning of the patient is considered fundamental to achieve the best exposure of the surgical site and therefore the best outcomes. It consists in hyperextension of the neck, which can be obtained through the interposition of a support between the operating table and patient’s shoulders. The wide and short neck of obese patients causes limited hyperextension, which results in a restricted operating field and, therefore, greater difficulty for the surgeon. It is precisely for this reason that many endocrine surgeons consider obese patients at greater risk of postoperative complications.
The aim of our study was to evaluate whether postoperative morbidity in obese patients undergoing thyroidectomy is really increased. In order to obtain a homogeneous sample and limit bias, only patients undergoing conventional open thyroidectomy alone were included in this work, while those submitted to minimally invasive video-assisted thyroidectomy (MIVAT) or who simultaneously underwent lateral and/or central neck dissection were excluded. Moreover, for the same purpose, only operations performed by the two most skilled endocrine surgeons of our Unit, with the same competence and experience in the field of thyroid surgery, were considered.
Also in our experience, as widely described in the literature, postoperative complications were not increased in obese patients. Furthermore, multivariate analyses even documented a lower risk of cervical haematoma in patients with high BMI.
As regards Clavien–Dindo classification, no patient was in grades IV and V. Moreover, it is important to note that no obese patient was in grade III.
About the postoperative stay, no statistically significant difference was found between the two groups.
As regards our result in terms of operative times, it was certainly influenced, at least in part, by the greater mean weight, and therefore size, of the thyroid gland in the group of obese patients. This difference in size may be due to a delayed diagnosis of thyroid disease in patients with elevated BMI, in whom cervical swellings deriving from thyroid nodules are more difficult to notice because of the high neck circumference. However, it is important to underline that, as in other studies, longer operative times had no clinical significance.
Most of the studies conducted so far on the correlation between elevated BMI and postoperative morbidity in the field of thyroid surgery confirm our findings [4, 10,11,12,13, 15]. Only three studies documented an increased occurrence of complications [5, 16, 17].
Buerba et al., who examined 18,825 patients undergoing thyroid surgery between 2005 and 2008, found that obese and morbidly obese patients had an increased risk of having at least one complication, especially wound complications. Moreover, they observed that morbid obesity was an independent predictor for urinary complications. However, it is important to underline that, in this study were not evaluated RLN injury and hypoparathyroidism, which are the two main complications of thyroidectomy [17].
Trésallet et al., analysing 1216 patients undergoing thyroidectomy for papillary thyroid carcinoma, observed no difference in terms of overall postoperative complications (including RLN injury, hypocalcaemia, bleeding requiring an emergency operative evacuation, abscess). However, they found that the risk of permanent complications, specifically RLN lesions, were greater in obese patients [5].
Jin et al. retrospectively reviewed 386 patients with papillary thyroid cancer who underwent total thyroidectomy and lateral neck dissection finding an increased occurrence of postoperative haematoma and wound infection in obese patients [16].
As regards operative times, as in our experience, an increase in patients with high BMI has generally been described [10, 12,13,14, 16, 17].
About the postoperative stay, only one study, conducted by Harari et al. on 443 patients undergoing thyroidectomy for papillary thyroid carcinoma, described an increase in patients with elevated BMI [4].
Our study has two main limitations. First of all, it is based on a retrospective analysis. The second limitation consists in the limited number of obese patients examined in relation to the low occurrence of some complications following thyroidectomy, specifically recurrent laryngeal nerve injury, cervical haematoma and wound infection. This last condition strongly hinders the achievement of a statistical power suitable for an accurate evaluation of these operative complications.
