Microsurgical management of ventrally located intradural extramedullary spinal cord tumors via posterior approach: Technical considerations and outcomes

Objective: Meningiomas and schwannomas are the most commonly encountered intradural extramedullary (IDEM) spinal cord tumors, which can lead to spinal cord compression and limb dysfunction. Due to the unique anatomical barrier provided by the arachnoid or pia mater, complete excision of these tumors is achievable through surgical intervention. While some studies have suggested the feasibility of using the posterior approach for ventral IDEM tumors, there is a lack of research on surgical management strategies and functional outcomes for these tumors. Methods: This study composed of 58 consecutive patients who underwent complete resection of IDEM tumors. Ventral IDEM tumors were removed through a narrow space between the dura and the spinal cord, without retracting or rotating the spinal cord, using the posterior approach. The baseline characteristics of the patients, including sex, age, tumor position at the spinal level, histopathological type, percentage of tumor occupying the intradural space, duration of surgery, perioperative neurological complications, neurological outcomes, and recurrence, were retrospectively analyzed. Results: The study included 28 cases of meningiomas and 30 cases of schwannomas. Among these, 24 patients had ventral IDEM tumors, while 34 had dorsal IDEM tumors. There was no statistically significant difference in operative time between the two groups. Importantly, the comparison of preoperative and postoperative McCormick scores or KPS changes showed no statistically significant difference (p = 0.063), indicating similar improvements in neurological function post-surgery. Each group had one case of cerebrospinal fluid leakage identified, and no recurrences were observed in either group during the follow-up period. Conclusion: Complete resection of ventral IDEM tumors can be achieved with clinical outcomes comparable to dorsal IDEM tumors through a posterior approach. Therefore, a thorough understanding of the anatomical and growth characteristics of IDEM tumors is essential for safe excision. However, the posterior approach should be used cautiously and with a full understanding of its limitations.