Image Merge Tailored Access Resection (IMTAR) of Spinal Intradural Tumors. Technical report of 13 Cases.

OBJECTIVE: Standard translaminar approaches for intradural extramedullary (IDEM) tumors require extensive soft tissue dissection and partial facet removal. Ventral lesions may necessitate wider bone resection with subsequent possible spinal instability. Any manipulation of an already compromised spinal cord may lead to neurological injury. We describe an image-guided minimal access technique for IDEM tumor resection. METHODS: Retrospective chart review of 13 consecutive patients after institutional ethics committee approval. We superimpose preoperative magnetic resonance imaging data with intraoperative 3-dimensional fluoroscopic images, allowing to simultaneously visualize osseous anatomy and the soft tissue lesion using appropriate windowing. We then plan optimal angle of trajectory to the tumor, which defines the skin incision and the transmuscular trajectory. A tubular retractor is placed to span the tumor. Microsurgical tumor resection is then carried out using this angle of approach. RESULTS: Thirteen patients (mean age. 57 years; male-tofemale ratio, 10: 3) were operated on during 28 months. Gross total resection was achieved in all patients. Neurological improvement occurred in 12 of the 13 patients. There was no neurological deficit outside of the expected sensory loss due to intentional nerve root sacrifice. No mechanical pain nor tumor recurrence were noted during the follow-up (mean, 16 months; range, 2-30 months). CONCLUSIONS: Image merge tailored access resection appears to be at least equivalent in terms of tumor resection, blood loss, and complications to other tubular techniques. It may reduce risks of neurological deficit and spine instability. Image merge tailored access resection is a novel application of merging intraoperative fluoroscopic images with preoperative magnetic resonance images for tailored IDEM resection.