Delayed Screw Migration Following Anterior Cervical Discectomy and Fusion

To identify the clinical and surgical characteristics and treatment options of patients suffering delayed (>1 month) screw back-out after anterior cervical discectomy and fusion (ACDF). A systematic review was performed searching Embase, Medline, and Scopus for relevant case studies and case series of delayed screw back-out after ACDF. A total of 25 studies encompassing 31 patients were identified and included. Average time to screw back-out was 4.6 years. Fifty-two percent of patients presented with dysphagia, and 61% had a pharyngoesophageal injury. Five patients were asymptomatic; 25 patients underwent surgery to remove hardware, 12 patients had surgical repair of the esophagus or hypopharynx, and 4 patients were managed conservatively. Antibiotic duration when given ranged from 2 weeks to 6 months. Nil per os (NPO) duration ranged from 4 days to 3 months. The risk of screw back-out is low, but it can be a devastating complication. The majority of reported cases developed pharyngoesophageal injury and dysphagia. Surgery is often required to remove the hardware and repair any damage to the esophagus or hypopharynx, and may require prolonged antibiotics and NPO. Rarely, patients may be asymptomatic and treated conservatively; but in 7 patients in this series in whom back-out was initially managed conservatively there was worsening back-out or injury that occurred an average of 29 months later.