Spinal subependymoma surgery: do no harm. Little may be more!

 Outline the reported diagnostic and operative findings, and evaluate the surgical treatment outcome to clarify the best available recommendations.  Ovid Medline, Embase and PubMed central databases were searched from inception until January 2019 using the terms (subependymoma and (spinal or cervical or thoracic)). The articles were reviewed for reported spinal subependymoma cases perioperative management and treatment outcomes.  A total of 49 papers provided data on 105 cases. 47 cases were reported in the last 5 years. The reported cases were two medullary-cervical, 35 cervical, 32 cervicothoracic, 21 thoracic, 12 thoracolumbar and three lumbar. Spinal subependymomas typically arise from within the central spinal canal, giving the appearance of an intramedullary mass, usually eccentric to one side. Symptoms at presentation ranged between 1 month to 17 years, (mean 3.5 years, median 2 years) and were over 3 years in 36, and over 8 years in 12 cases. Sensory symptoms are the most frequent 75(80%), followed by weakness in 60(64%), pain in 45(48%) and sphincter disturbance in 24(25%). Postoperative neurological function was reported in 78 cases, and worsening was reported in 40 cases (51%), of which, 29 (72%) had complete resection, 6 (15%) had subtotal resection and 5 (12%) had partial resection. Neurological status remained the same in 24 (30%) and improved in 14 (18%).  The reviewed cases report a rate of 65% total resection of which 57% had worsened function after surgery. There were no reports of malignant transformation; therefore, long-term survival is expected, and surgical caution should be exercised where there is minimal symptom progression.