Introduction: Posterolateral sulcus (PLS) approach of the spinal cord, being equivalent to the dorsal root entry zone (DREZ) myelotomy, may offer the satisfactory exposure of the spinal intramedullary tumor if applied appropriately. The purpose of this retrospective case analysis was to discuss the surgical indication and technique of PLS approach for spinal intramedullary lesions.

Methods: Seventy nine consecutive patients with spinal intramedullary lesions underwent the surgery over the past 7.5 years in our institute. PLS approach was applied in 20 of 79 patients (25.3%). Surgical indication of PLS approach was (1) for the intramedullary lesions situated laterally in the spinal cord and that do not contact the posterior or lateral surfaces on MR images before surgery, (2) for the patient who demonstrated severe segmental pain on the lesion side before surgery, (3) in cases that require the re-operation after midline approach, or (4) for spinal biopsy. Neurological condition was assessed using the modified McCormick functional schema and sensory pain scale.

Results: Functional analysis early (within one month) after surgery demonstrated satisfactory or acceptable outcome except 2 cases of repeated intramedullary hemorrhage of cavernous malformation and anaplastic astrocytoma. Average modified McCormick functional schema score before surgery was 3.5, stable to 3.4 early after surgery. Mean sensory pain scale before surgery was 2.9, improving significantly to 2.1 early after surgery.

Conclusions: PLS approach can be one of the surgical choices to the spinal intramedullary tumors, if applied appropriately. Better indication for PLS approach may be the small or medium-sized tumor of the uneven location within the spinal cord.

Patient Care: Careful selection of surgical approach to the spinal intramedullary tumor may be of importance to secure the functional recovery after surgery.

Learning Objectives: By the conclusion of this session, participants should be able to discuss the surgical indication and technique of PLS approach for spinal intramedullary lesions.

References: Takami T, Yamagata T, Ohata K. Posterolateral Sulcus Approach for Spinal Intramedullary Tumor of Lateral Location: Technical Note. Neurol Med Chir (Tokyo). 2013; 53(12): 920-927 Takami T, Yamagata T, Naito K, Arima H, Ohata K. Intraoperative assessment of spinal vascular flow in the surgery of spinal intramedullary tumors using indocyanine green videoangiography. Surg Neurol Int. 2013 Oct 4;4:135. Takami T, Naito K, Yamagata T, Ohata K. Surgical Management of Spinal Intramedullary Tumors: Radical and Safe Strategy for Benign Tumors. Neurol Med Chir (Tokyo). 2015; 55(4): 317-327