A new concept for making decisions regarding the surgical approach for spinal meningiomas: The T-line, a preliminary study

ObjectiveThe objectives of this study were to propose the T-line, new assistant lines for making decision of surgical approach for anterior spinal meningioma.BackgroundThere was a controversy over how spinal meningiomas should be approached when they were located especially anteriorly to the spinal cord because treatment of dura should be performed without spinal cord injury.MethodsWe introduce a new concept for making a decision for the surgical approach for spinal meningioma. If the point of intersection of the tangent of the tumor and spinal cord (T-line 1) and the bisected line of the facet (T-line 2) is located on the anterior side of the lamina (T-line [+]), tumors should be excised via the posterolateral approach. If the point of intersection is located on the posterior side of the lamina (T-line [−]), tumors can be excised via the posterior approach. Twelve patients with spinal meningioma who were diagnosed and surgical treated in our department constituted the study population.ResultsIn the 8 cases with T-line (+), tumors were excised via the posterior approach. However, in the 2 cases with T-line (−), tumors were excised via posterolateral approach. The average of preoperative JOA score was 10.2 ± 2.7. The Japanese Orthopedic Association Scoring System for cervical myelopathy (JOA score) significantly improved to 14.1 ± 1.5 at the final follow-up (P < 0.05). The recovery rate of the JOA score was 55.4%.ConclusionThe T-lines may be useful when making decisions for the surgical approach for spinal meningioma.