Contralateral Lobe Volume Brings Us One Step Closer to the Prediction of Hypothyroidism Following Partial Thyroid Resection

Abstract

We live in an age of patient empowerment in which patients can search online for information about their procedures, and expect (rightfully so) to have informed discussions about the risks and benefits of an operation with their surgeon. Consequently, surgeons must be prepared to have thorough conversations with patients about the pros and cons of an operation. Extensive work has been done to determine the optimal operation for patients with thyroid nodules: the Bethesda criteria laid the groundwork for determining the best operation based on thyroid nodule cytopathology, 1 and testing with AFIRMA or for genetic mutations has furthered this field.Patients can choose to undergo a partial thyroid resection or a complete thyroidectomy for lesions diagnosed as follicular neoplasms, suspicious for follicular neoplasms, or suspicious for malignancy. The risks associated with partial resection are less severe than those of complete thyroidectomy. However, the risks of both operations are low and therefore the decision is usually centered on the patient's willingness to consider a second surgery, if necessary, and the uncertain potential for needing long-term thyroid hormone replacement. Data to guide patient decision making on the likelihood of requiring a thyroid hormone supplement have been limited to date. Reports of thyroid hormone replacement intolerance due to an impaired sense of well-being, fatigue, weight gain, hair loss, nightmares and other untoward complications of treatment have marred patient perception of the desirability of thyroid hormone replacement.In a prospective study, Lang et al. cleverly examined the association between measurements of the contralateral thyroid lobe volume from the preoperative ultrasound and the development of biochemical hypothyroidism following hemithyroidectomy.2 A risk prediction scoring system was developed to prognosticate the likelihood of developing postoperative hypothyroidism; this model incorporated body surface area (BSA)-adjusted remnant volume, the preoperative thyroid-stimulating hormone (TSH) level, and the number of nodules found in the resected lobe.2 These findings strengthen the observations by De Carlucci et al. regarding the importance of remnant volume, 3 and are concordant with the existing body of literature that has demonstrated the presence of antithyroid peroxidase antibodies, thyroiditis, a multinodular goiter, preoperative thyrotoxicosis, and a TSH level within the high-normal range to be associated with the development of biochemical hypothyroidism following hemithyroidectomy. [3][4][5][6][7] Despite the novel approach to risk-stratify patients regarding the development of biochemical hypothyroidism, the paper does not solve the problem of predicting clinically significant hypothyroidism (i.e. hypothyroidism requiring treatment) as most postoperative biochemical hypothyroidism resolves spontaneously. 6 In this study, 17 of 44 (38.6%) patients with postoperative biochemical hypothyroidism eventually required thyroxine supplementation. This result f...