Evaluation of the rate of decompression in anterior cervical corpectomy using an intra-operative computerized tomography scan (O-Arm system)

The purpose of this study was to evaluate the efficacy of intra-operative computerized tomography (CT) scanning in the analysis of bone removal accuracy during anterior cervical corpectomy, in order to allow any necessary immediate correction in the event of inadequate bone removal. From September 2009 to December 2010 we performed an intra-operative (CT) scan using the O-Arm((TM)) Image system to assess the rate of central and lateral decompression in all patients treated for cervical spondylotic myelopathy by anterior cervical corpectomy and fusion. Out of a population of 187 patients admitted to our department, with a diagnosis of myelopathy due to spondylotic degenerative cervical stenosis, 15 patients underwent a surgical treatment with anterior cervical corpectomy and fusion. There were nine males (60%) and six females (40%); the mean age was 52.4 years, ranging from 41 to 57 years. The pre-operative radiologic investigations (MRI and CT scans) revealed in the nine patients (60%) the extent of the compression to one vertebral body (C4 one case, C5 four cases, C6 four cases), while in the six cases (40%) the compression regarded two vertebral body (C3 and C4 one case, C4 and C5 two cases, C5 and C6 three cases). During surgery, when the decompression was judged completely, a CT scan was performed: in 11 cases (73.3%) the decompression was considered adequate, while in four cases (26.7%) it was deemed insufficient and the surgical strategy was changed in order to optimize the bone removal. In these cases an additional scan was taken to prove the efficacy of decompression, achieved in all patients. Intra-operative CT scan performed during cervical corpectomy is a really useful tool in helping to ensure complete bone removal and the adequacy of surgery. The O-arm((TM)) Image system grants optimal image quality, allowing correctly assessing the rate of decompression and, in any case of doubt, allows an intra-operative evaluation of the final correct positioning of the graft.