Intraoperative magnetic resonance imaging–augmented transoral resection of axial disease

Abstract

Because transoral decompression of the cervicomedullary junction is compromised by a narrow surgical corridor, the adequacy of decompression/resection may be difficult to determine. This is problematic as spinal hardware may obscure postoperative radiological assessment, or the patient may require reoperation. The authors report three patients in whom high-field intraoperative magnetic resonance (MR) images were acquired at various stages during the transoral resection of C-2 lesions causing craniocervical junction compression. In all three patients the lesions involved the cervicomedullary junction: one case each of plasmacytoma and metastatic breast carcinoma involving the odontoid process and C-2 vertebral body, and one case of basilar invagination with a Chiari type I malformation. All three patients presented with progressive myelopathy. Surgery-planning MR imaging studies, performed after the induction of anesthesia, demonstrated the lesion and its relationship to the planned surgical corridor. Transoral exposure was achieved through placement of a Crockard retractor system. In one case the soft palate was divided. Interdissection MR imaging revealed that adequate decompression had been achieved in all cases. In the two patients with carcinoma, posterior instrumentation was placed to achieve spinal stabilization. Planned suboccipital decompression and fixation was averted in the third case because MR imaging demonstrated that excellent decompression had been achieved. Intraoperatively acquired MR images were instrumental in determining the adequacy of surgical decompression. In one patient the MR images changed the planned surgical procedure. Importantly, the acquisition of intraoperative MR images did not adversely affect operative time or neurosurgical techniques, including the instrumentation procedure.