[Microscopic resection of lumbar intraspinal tumor through keyhole approach: A clinical study of 54 cases]

To explore the feasibility and key technology of microscopic resection of lumbar intraspinal tumor through microchannel keyhole approach.

The clinical features, imaging characteristics and surgical methods of 54 cases of lumbar intraspinal tumor which were microscopically operated by microchannel from February 2017 to September 2019 were reviewed and analyzed. There were 8 cases of extradural tumor, 3 cases of extra-and intradural tumor and 43 cases of subdural extramedullary tumor (including 3 cases of ventral spinal tumor). The tumors were 0.5-3.0 cm in diameter. The clinical symptoms included 49 cases of pain in the corresponding innervation area, 5 cases of sensory disturbance (numbness) at or below the tumor segment, 7 cases of limb weakness and 2 cases of urination and defecation dysfunction.

In the study, 37 tumors were resected through hemilaminectomy, 14 tumors were resected through interlaminar fenestration, 3 tumors were resected through hemilaminectomy or interlaminar fenestration combined with facetectomy of medial 1/4 facet. All of the 54 tumors were totally resected. The operation time was 75-135 min, with an average of 93.3 min. The postoperative hospital stay was 4-7 days, with an average of 5.7 days. Postoperative pathology included 34 cases of schwannoma, 4 cases of meningioma, 9 cases of ependymoma, 1 case of enterogenous cyst, 5 cases of teratoma/epidermoid/dermoid cyst, and 1 case of paraganglioma. No infection or cerebrospinal fluid leakage was found after operation. No neurological dysfunction occurred except 1 case of urination dysfunction and 4 cases of limb numbness. The follow-up period ranged from 3 to 33 months with an average of 14.4 months. Five patients with new onset symptoms returned to normal. The pain symptoms of 49 patients were completely relieved; 4 of 5 patients with hypoesthesia recovered completely, the other 1 patient had residual mild hypoesthesia; 7 patients with limb weakness, and 2 patients with urination and defecation dysfunction recovered to normal. No spinal instability or deformity was found, and no recurrence or residual tumors were found. According to McCormick classification, they were of all grade Ⅰ.

The lumbar intraspinal extramedullary tumors within two segments (including the ventral spinal tumors) can be totally resected at stage Ⅰ through microchannel keyhole approach with appropriate selection of the cases. Microchannel technique is beneficial to preserve the normal structure and muscle attachment of lumbar spine, and to maintain the integrity and stability of lumbar spine.