Minimally Invasive Oblique Retroperitoneal Approach for Extraforaminal Lumbar Schwannoma: Technical Challenges and Literature Review

Traditional surgical techniques for extradural lumbar schwannomas are associated with considerable morbidity, including spinal instability and injury to the viscera and lumbar plexus. Mini-mally invasive approaches decrease soft tissue damage, blood loss, and postoperative length of stay. For select extraforaminal schwannomas, a minimally invasive lateral transpsoas approach affords a direct surgical corridor. A 53-year-old obese female presented with 1 year of left ilio-psoas weakness and L3 radiculopathy refractory to conservative management. Lumbar spine magnetic resonance imaging revealed a contrast-enhancing mass within the left psoas muscle consistent with an extraforaminal L3 schwannoma. The patient underwent minimally invasive oblique retroperitoneal surgical resection. Intraoperatively, the nerve root was splayed over the superior-lateral portion of the tumor limiting us to subtotal resection with nerve root preservation. The patient had improvement of pain and weakness that persisted at a 3-month follow-up. A minimally invasive lateral/oblique transpsoas approach provides a direct surgical approach for extraforaminal schwannoma. Patient body habitus and the nerve root relationship to the tumor may present limitations for the safe extent of resection.