Iatrogenic Fracture in a Patient of Ankylosing Spondylitis Planned for Surgical Correction of Chin-on-Chest Deformity

Abstract

Ankylosing spondylitis (AS) is a progressive systemic chronic inflammatory rheumatic disease that causes arthritis of spine and sacroiliac joints and finally results in contracture or bony fusion of these joints. The ankylosed spine has increased propensity to fracture due to rigidity, long lever arms, and osteoporosis. However, iatrogenic fracture occurring in AS patients with chin-on-chest deformity during positioning has not been reported. A 46-year-old male, known case of AS, presented with progressive deformity of neck for the last 6 months due to C5 fracture with C4/5 dislocation. He had chin-on-chest deformity with chin-brow vertical angle of 106o with spastic tetraparesis (mJOA score 6, Nurick grade-3). The patient was put on sustained halo-gravity traction by gradually increasing the weight up to 30 lbs for 4 weeks and then was planned for deformity correction. After intubation and application of same traction, we found anterior wedge opening and fracture through C6/7 disc space. His neurology was found to be same as in the preoperative state on neural monitoring and wake up test. Front and back instrumented fusion was done with anterior bone grafting. Postoperatively, he was maintained on halo-vest immobilization for three months. By the end of first year, the fracture had united well and he was mobilizing well with mJOA score 13 and Nurick grade-1. AS patients are at higher risk of fracture and need utmost care while positioning during surgery. Traction or any corrective maneuver must be done carefully.