gms | German Medical Science

Objective: Intramedullary tumors that arise within the conus medullaris represent uncommon entities. These tumors demand special surgical considerations with regards to anatomical, clinical and radiological presentation. Therefore, this study was designed to evaluate clinical presentation, surgical approaches and postoperative outcome in such lesions.

Methods: This study analyzed retrospectively the patient charts in the period of October 2004 to April 2006. Clinical presentation, time of disease, radiological findings, surgical approach, extension of resection and postoperative outcome at discharge and six month follow-up. Neurological functions were scored according to Samii and Kleekamp classification considering sensory deficts, pain, motor weakness, gait ataxia, bladder and bowel function pre- and postoperatively. All patients underwent pre- and postoperative (MRI) to evaluate the extension of resection.

Results: Between October 2004 and April 2006 eight patients were operated on at our Department with intramedullary conus lesions. There were two teratomas, one mixopapillary ependymoma, two cavum terminalis cysts, one lipoma and two vascular lesions (one cavernoma and one dural AV-fistula). Pain was the leading symptom occurring as localised lumbar pain or irradiated sciatica. Time to diagnosis ranged between six weeks and eight months. At admission, bladder and bowel dysfunction were observed in 62,5% and 75% of the patients, respectively. Motor weakness occurred in 50% of the patients before surgery. Intraoperative electrophysiological monitoring-SEP, MEP, anal sphyncter electromyography-was performed continuously in all procedures. The lesions were totally resected in four patients, subtotally in two, one biopsy and one closure of the dural AV-fistula. The midline approach was used in all patients but one, who harboured an eccentrical superficial cavernoma. At the follow-up examination, pain and bladder dysfunction were the neurological signs/symptoms that were improved most from the surgical procedure. Motor and bowel function remained mostly unchanged in comparison to preoperative status. Gait/ ataxia worsened in three cases.

Conclusions: Intramedullary conus tumors are uncommon lesions that must be considered in the differential diagnosis of lumbar pain. Delayed diagnosis may cause further neurologic deficits. The postoperative outcome is related to the preoperative neurological status. Pain reduction and bladder function achieved the best results at six-month follow-up.