Clinical and Radiological Outcome after Posterior Occipitocervical Fusion

Aim: Decompression of the cervical spine with or without fusion is routinely achieved through an anterior approach. A posterior approach with fusion offers an alternative method, which is used by default at our department since March 2012. Furthermore, we have the privilege of an intraoperative computed tomography (iCT) in the hybrid OR, which is regularly used to confirm the correct placement of screws. The aim of this study was to analyze clinical and radiological results of posterior cervical spinal fusion (PCF) and to examine the benefit of an iCT for the detection of screw misplacement.

Methods: From March 2012 to April 2016, 25 patients received a PCF at the Department of Neurosurgery, Kantonsspital Aarau. The patients suffered from a wide range of cervical spinal disorders, including degenerative and neoplastic diseases as well as spinal injuries. Fourteen patients (56%) had previously received cervical spinal fusion with an anterior approach. PCF after initial anterior fusion was performed in cases with persisting symptoms, especially after loss of correct cervical alignment and instability. PCF as the primary treatment option was undertaken in patients with significant preoperative instability or malalignment. In a retrospective study, clinical and radiological outcome parameters including adverse events were analyzed over a mean time period of 1.85 years ± 1.89 years.

Results: The mean age at the time of surgery was 59 ± 13 years with 14 male patients (56%) and 11 female patients (44%). The PCF incorporated one to nine segments with a mean of 4.68 segments. At the last follow-up, an improvement in pain was reported in 20 patients (80%). Seventeen patients (68%) had no sensorimotor deficit. An improvement in motor deficits was reported in five patients (20%). Gait disturbance was present in another five patients (20%). Of those, four patients (16%) reported a significant improvement. Revision surgery was needed in five patients due to surgical site infection (n = 3) or cerebrospinal fluid leak (n = 2). The perioperative mortality rate was 4%.

An iCT scan was performed in 19 cases (76%). Incorrect placement of screws was detected in seven patients (28%); eight screws were replaced intraoperatively. No revision surgery to correct screw misplacement was needed at a later stage.

Conclusions: The posterior occipitocervical fusion in the hybrid OR setting offers a safe and effective treatment option for cervical spinal fusion with a good radiological and clinical long-term outcome.