Cervicothoracic Spinal Osteotomy of Treatment of Chin-on-chest Deformity in Ankylosing Spondylitis Patients

Background: Chin on chest deformity is an infrequent, disabling manifestation of ankylosing spondylitis. Treatment is osteotomy at the cervicothoracic junction. The current study seeks to characterize the clinical status of patients treated surgically for chin-on-chest deformity related to ankylosing spondylitis including signs, symptoms and radiographic parameters.

Methods: The medical records and radiographs of 27 ankylosing spondylitis patients treated with posterior cervicothoracic extension osteotomy were retrospectively reviewed with an average 4.0 year follow-up ranging from 2 years to 21 years, 10 months. Details about history of trauma, preoperative symptoms, neurologic status, preoperative radiographic alignment, degree of correction, loss of correction over time, radiographic fusion status, relief of symptoms, and complications are reported.

Results: There were 1 female and 26 male patients, with a mean age of 52.2 years. Thirteen had a history of overt trauma that initiated progression of symptoms and deformity. Preoperative symptoms included difficulty with horizontal gaze and field of vision in 27, neck pain in 25, difficulty chewing and swallowing in 20, and difficulty shaving in 13. Sixteen were neurologically normal, 7 had mild myelopathy, and 4 were severely myelopathic or quadriparetic. Mean sagittal correction was 37.6 degrees (range 15 to 84 degrees). Mean loss of correction was 2.6 degrees, most significantly in the setting of delayed union (2 patients) or additional cervical trauma (2 patients). Twenty-one of 24 patients with neck pain experienced significant pain relief. Eighteen of 19 patients with swallowing difficulty improved. Ten of 11 patients who were neurologically abnormal improved. One patient developed quadriplegia and died due to subluxation of the osteotomy. Two other patients died during the 2-year follow-up period due to unrelated causes. Five patients experienced C8 nerve root irritation postoperatively.

Conclusions: Chin-on-chest deformity is often a consequence of trauma. Neurologic abnormalities are frequent. Posterior cervicothoracic extension osteotomy can reliably achieve improvement in sagittal alignment, horizontal gaze, field of vision, neck pain, chewing and swallowing difficulties, and neurologic abnormalities. Internal fixation is recommended to prevent subluxation, delayed union or nonunion which can lead to partial loss of correction and/or neurologic injury. There is a risk of death and/or catastrophic neurologic injury from the procedure.