Arachnoscopy: a special application of spinal intradural endoscopy

The microsurgical removal of obstructions to CSF flow is the treatment of choice in the surgical management of intradural arachnoid cysts. Cardiac-gated phase-contrast MR imaging is an effective tool for the primary diagnosis and localization of arachnoid cysts. Microsurgery, however, does not lend itself to assessments of further adhesions beyond the borders of the exposed area. The use of a thin endoscope allows surgeons to assess intraoperatively whether the exposure is wide enough. Between 2006 and 2010, a single neurosurgeon performed 31 consecutive microsurgical procedures with endoscopic assistance in 28 patients with spinal arachnoid adhesions. A MurphyScope endoscope was used for this purpose. The CSF flow was studied before and after surgery in all patients by using phase-contrast MR imaging in the region of the craniocervical junction, the cervical spine, the thoracic spine, and the lumbar spine. In all 31 procedures, CSF flow obstructions were detected at the level identified by phase-contrast MR imaging. In 29 procedures, image quality was sufficient for an inspection of the adjacent subarachnoid space. In 6 cases, the surgeon detected further adhesions that obstructed CSF flow in the adjacent subarachnoid space that were not visualized with the microscope. In all cases, these adhesions were identified and removed during microsurgery. Arachnoscopy is a helpful adjunct to microsurgery and can be performed safely and easily. It allows the surgeon to detect further adhesions in the subarachnoid space that would remain undetected by microscopy alone.