[Microscopic keyhole technique for surgical resection of thoracic spinal meningioma via an oblique placing tube].

Objective: To report the methods and clinical outcomes of microscopic minimally invasive keyhole technique for surgical resection of thoracic spinal meningiomas. Methods: Thirty-nine patients with thoracic spinal meningiomas received keyhole surgery from May 2013 to June 2017 in the Department of Spine Surgery, Fujian Provincial Hospital. A working channel with a diameter of 1.8 cm was inserted percutaneously about 2.0 to 3.5 cm away from the mid-line. Dorsally attached tumors were resected with hemilaminectomy fenestration; for the spinal meningiomas located in the lateral side of the spinal cord, hemilaminectomy combined with partial facetectomy were used; hemilaminectomy combined with hemifacetectomy fenestration were used for spinal meningiomas located ventrally. No internal fixation was performed in all cases. Clinical outcome was assessed using the visual analog scale (VAS) for pain relief and the American Spinal Injury Association (ASIA) scale for evaluation of the function of the spinal cord after surgery. The pre-and post-operative data were compared by paired t test. Results: Among the 39 patients, the tumors in 36 cases located in the thoracic spine and 3 in the cervicothoracic junction. Complete resection was achieved in all patients. Mean operative time was (148±21) min (range, 120-185 min). Mean blood loss during surgery was (101±27) ml (range, 50-200 ml). No infection or aggravation of spinal cord injury occurred after operation, except for 3 patients who had postoperative cerebrospinal fluid leakage that recovered after conservative treatment. The mean hospital stay was (6.1±0.8) days (range, 5-9 days). Patients were followed-up for a period of 9 to 57 months, with a mean follow-up time of (29±13) months. At the last follow-up, all patients had a reduced level of pain as suggested by an average VAS score that improved from (7.38±1.71) to (0.31±0.63), the ASIA grade improved in all patients except for 2 cases (5.1%), 24 cases (61.5%) improved by 1 grade, 9 cases (23.1%) improved by 2 grades, and 4 cases (10.3%) improved by 3 grades. No evidence of tumor recurrence or secondary spinal instability was observed in any patients during the postoperative follow-up. Conclusion: Microscopic minimally invasive keyhole technique can be used to completely resect the thoracic spinal meningiomas; such surgical procedures convey reliable clinical outcomes and good postoperative spinal stability.