Aim and indications of spinal angiography for spine and spinal cord surgery: Based on a retrospective series of 70 cases.

AIM: For spinal surgery, computerized tomography (CT scan) and magnetic resonance imaging (MRI) have clear indications and are easily accessible. In contrast, the indications and the use of spinal angiograms (SA) remain unclear, and many centres performing spinal surgery do not have an access to SA. Based on a retrospective study, the role of SA in spinal surgery is assessed and their indications are discussed.

MATERIAL AND METHODS: A retrospective series of 72 SA in 70 patients is presented. No procedural accident occurred. SA was performed under general anaesthesia in 57 cases (82%). In 61 patients, locating the radiculomedullary arteries (RMA) was obligatory and performed in all cases: for 14 patients (21%), RMA were identified using the forecasted surgical approach (4 patients with degenerative disc disease out of 10 in the entire series were included), and modified. No ischaemic complications were observed in the series. Thirty-nine patients were treated for a tumour that was considered hypervascular (based on a histological hypothesis or the MRI data): 20 of them (51%) were preoperatively embolised and in only 8 cases was the operation considered "haemorrhagic" by the surgeon (among which, 3 intramedullary hemangioblastomas were included). No accident was observed during the embolisations. Thirteen patients presented with a vascular or haemorrhagic lesion (4 arteriovenous malformations, 6 dural arteriovenous fistulas, 3 intramedullary cavernomas): in all these cases, the SA was indispensable for the diagnosis and the decision-making process. Seven patients were treated by embolisation. In the last 8 cases, SA was considered for the diagnosis of a clinical worsening myelopathy with a non-contributive MRI, but it was not useful in providing a positive diagnosis.

CONCLUSIONS: SAs were performed with different goals: (i) localization of RMA when a surgical approach between T4 and L2 involved the intervertebral foramen, or when an anterior approach was considered in order to avoid severe ischaemic complications (40% of the degenerative disc patients and 33% of the extramedullary tumour patients in this series); (ii) preoperative embolisation in cases of extramedullary tumours probably considered hypervascular (51% of the cases in the series) or in cases of arteriovenous shunt lesions (7 of 13 patients were treated by embolisation); (iii) as a diagnostic tool, SA is indispensable when MRI can reveal vascular abnormalities; it also provides information about the vascularisation as well as the endovascular possibilities in extramedullary tumours. In contrast, SA was not useful for intramedullary tumours because the RMA preoperative localisation is not mandatory (posterior approach), and embolisation seemed ineffective. SA was also not useful for the diagnosis of myelopathy with normal MRI. In the future, angiograms and MR angiography of the spinal cord may be useful in order to avoid general anaesthesia for a diagnostic procedure, but not practical to obtain access for endovascular treatment.