Anterior cervical spine surgery opens up concerns about thyroid function

The anterior approach for cervical discectomy and fixation is a valuable procedure for decompression of the spinal cord in patients with severe canal stenosis and stabilization of cervical vertebral column. Although some studies have investigated the thyroid complications especially in cervical cancer surgery or recently in tracheostomy, little research has been performed on the anterior spine surgery so far. The present study aimed to evaluate possible changes in the thyroid in patients experiencing anterior cervical approaches for degenerative diseases.

Seventy patients who were undergoing anterior cervical spine surgery were selected and their demographic information was recorded, including age, sex, weight, body mass index (BMI), and medical records. Thyroid hormones (TSH, free T4, and free T3) were measured before surgery and three months after surgery.

Most patients had cervical disc herniation (60%). The mean duration of surgery was 71.9 ± 8.36 minutes (range: 60-90 minutes). Twenty-one patients (30%) had anterior plating while 49 patients (70%) did not. Spearman's correlation coefficient was used to examine the correlation of the following variables with TSH changes: Number of operated cervical levels, level of operated spine, incision type, duration of surgery, type of surgery (ACDF or ACCF). None of these variables showed a significant correlation. Meanwhile, a significant and direct correlation was observed between TSH changes and age.

Although the results of our study did not show any signs of functional changes due to thyroid tissue injury during surgery, based on rare case reports and age-related laboratory changes, we recommend thyroid function tests for diagnosing subclinical thyroid dysfunction before anterior cervical spine surgery in patients with degenerative diseases and especially in older adults.