Minimally Invasive Direct Lateral Transpsoas Approach for the Resection of a Lumbar Plexus Schwannoma: Technique Report.

Traditional techniques for resection of lumbar plexus tumors have been associated with approach-related morbidity. We describe a case utilizing a minimally invasive transpsoas lateral access approach to resect a retroperitoneal tumor of the lumbar plexus.  We report a case with an extradural retroperitoneal schwannoma of the L4 nerve root that was treated with a minimally invasive direct lateral transpsoas approach using atraumatic tissue dilators and an expandable tubular retractor. The use of directional and continuous electromyographic monitoring was critical in locating the plexus and positioning the retractor immediately anterior to the tumor.  The patient tolerated the procedure well without postoperative complications. The operative approach was direct and intraoperative blood loss was negligible. The patient demonstrated improved left leg strength and ambulation and resolution of paresthesias.  A minimally invasive direct lateral transpsoas access approach is an effective technique to safely and adequately resect extradural retroperitoneal lumbar plexus tumors.