[Minimally invasive removal of dumbbell shaped schwannomas with transforaminal lumbar fusion: a retrospective study with a minimum 3-year follow-up].

Currently, there are no standards in surgical treatment of dumbbell-shaped tumors of lumbo-foraminal region.

Objective: To evaluate the effectiveness and long-term results of minimally invasive resection of dumbbell-shaped lumbar schwannomas Eden type 2 and 3 combined with transforaminal lumbar interbody fusion and transpedicular stabilization.

Material and methods: A retrospective study included 13 patients (8 men and 5 women) with lumbar dumbbell tumors Eden type 2 and 3 who underwent minimally invasive facetectomy through posterolateral anatomical corridor, microsurgical tumor resection and MI TLIF. We analyzed intraoperative parameters, neurological functions (ASIA scale), clinical characteristics (ODI, SF-36), and complications. Resection quality and area of the multifidus muscle were assessed according to MRI data. All patients were followed-up throughout at least 3-year.

Results: Surgery time was 147 min, blood loss - 118 ml, hospital-stay - 7 days. Clinical parameters significantly improved in the follow-up period: ODI score decreased from 72 to 12 (p=0.004), SF-36 PCS increased from 26.24 to 48.51 (p=0.006) and MCS score increased from 29.13 to 53.68 (p=0.002). According to MRI data, no tumor recurrences and severe muscle atrophy (>30%) were observed after 3 years in all cases. Superficial wound infection occurred in 1 (7.7%) case. There were normal neurological functions (ASIA type E) in all patients.

Conclusion: Minimally invasive facetectomy through posterolateral approach with MI TLIF technology can be used for safe and effective resection of dumbbell-shaped schwannomas Eden type 2 and 3.