The Role of Preoperative Thyroid Function Testing Prior to Free Tissue Transfer

Introduction: Thyroid hormones are essential in regulation of body metabolism and potentially play a role in wound healing. Despite the importance of thyroid function in overall health status, there is no agreement on screening tests for asymptomatic adults. As such, many patients who require head and neck reconstruction using free tissue transfer have not been screened for thyroid function. In this study, we investigated whether there is a statistically significant difference between postoperative course of patients with and without hypothyroidism.

Methods: This is a retrospective chart review of patients who underwent reconstruction of head and neck defects with free tissue transfer at our institution between 2010 and 2019. We used the American Thyroid Association clinical guideline to identify the upper TSH limit of 4.12 mIU/L as being euthyroid. After identification of euthyroid vs hypothyroid patients based on this definition, the two groups were compared in terms of short and long-term outcomes of their free flap and hospital stay.

Results: From the 1,100 patients who had reconstruction of the head and neck defects with free flap, 76 patients had preoperative TSH within the month prior to the surgery ranging from 0.04 to 69.6 mIU/L. Of the total, 20 patients had high TSH levels ranging from 4.3 to 69.6 mIU/L and the rest were euthyroid. Almost all patients were treated for head and neck cancer. There was no significant difference between the two groups in terms of flap survival, length of hospitalization, and readmission within 30 days. However, patients with high TSH level had significantly higher rate of post-operative complications (odds ratio 3.35; 95% CI 1.12-10) such as hematoma, infection, and wound dehiscence. No significant difference between the two groups in terms of comorbidities such as peripheral vascular disease, smoking, diabetes, history of chemotherapy or radiation therapy.

Conclusions: Hypothyroid patients who undergo free flap reconstruction of head and neck defects experience higher rates of post operative complications but have comparable long-term flap outcomes to their euthyroid counterparts.