An Innovative System to Facilitate Extension Osteotomy in the Prone Position for Chin-on-Chest Deformity of Ankylosing Spondylitis

In the presence of chin-on-chest deformity of ankylosing spondylitis, positioning for extension osteotomy of the spine is a challenging endeavor. Conventional prone positioning equipment cannot safely accommodate all patients with advanced deformity where the chin brow angle approaches or exceeds 90°. Issues such as inability to accommodate the head and associated equipment while providing operative stability and venous congestion of the head represent significant perioperative risks. The sitting position has been advocated as an alternative but is suboptimal for surgical access and anesthetic care. We present a technical note for a positioning system developed to facilitate extension osteotomy in the prone position. A positioning device was designed to accommodate patients with advanced deformity. A series of patients with chin brow angles of up to 89° were positioned using our new system. We were able to facilitate safe extension osteotomy in the prone position, for procedures lasting up to 14 hours. All our patients were discharged home without significant complication. Our device is simply constructed and may be easily replicated in other institutions engaging in complex spine surgery. We hope our system provides clinicians with greater freedom to provide optimal perioperative care to their patients.