gms | German Medical Science

Objective: Ependymomas of the filum terminale are rare extramedullary tumors of the lower spinal canal. Due to their attachment to the conus and nerve roots their removal may pose significant problems. This paper will describe surgical techniques and postoperative results.

Methods: Hospital files, neuroradiological examinations, intraoperative documentations and follow-up examinations were analysed. The clinical course was documented with a neurological scoring system for each symptom and the Karnofsky score. Recurrence and survival rates were determined according to Kaplan-Meier statistics.

Results: In a series of 1126 patients with spinal tumors treated between 1977 and 2006, 438 extramedullary, intradural tumors (39%) were seen. Among these, 32 ependymomas of the filum terminale were encountered. No patient presented with seeding of an ependymoma of the posterior fossa. Three patients declined an operation whereas 29 were operated. They presented at an average age of 35±12 years after an average history of 24±44 months. Mean follow-up was 33±49 months. Pain was the first indicator of this tumor in 75% of patients and remained the major symptom for 71% in this series. Neurological deficits were not a regular feature in this patient group. Just 6% complained about significant sphincter problems despite the considerable size of these tumors in close proximity to the conus in most patients. Complete resections were achieved in 23 instances (79%), while 6 were removed subtotally. A transient postoperative neurological deterioration was observed in 2 patients only. There was no permanent surgical morbidity. Postoperative radiotherapy was applied in 3 patients after subtotal removal with no subsequent recurrence. The postoperative clinical course demonstrated a significant improvement of pain while the remainder of the neurological symptoms remained unchanged within the first postoperative year. Three tumor recurrences were seen among patients after complete resections, indicating a recurrence rate of 22% within 5 years. Subarachnoid seeding was seen in one patient after surgery, whereas one patient presented with preoperative subarachnoid dissemination of a spinal ependymoma.

Conclusions: Extramedullary ependymomas of the filum terminale may grow to enormous size and yet present with few neurological deficits. This paper indicates that these tumors can be removed safely with a low risk of permanent morbidity irrespective of their considerable size and involvement of the conus and caudal nerve roots.