[Comparative analysis between multi-segments intramedullary spinal cord congenital tumors and benign ependymomas]

To comparatively analyze the different and common points between multi-segments intramedullary spinal cord congenital tumors and benign ependymomas, such as the patient's age, gender, nervous functions and tumor location, longitudinal extension, and removed extent.

Data were studied from 12 patients with multi-segments intramedullary spinal cord congenital tumors and 19 patients with multi-segments intramedullary spinal cord benign ependymomas who underwent microsurgery for the tumor using a posterior approach. The tumor was exposed through dorsal myelotomy. Preoperative and postoperative nervous functions were scored using the Improved JOA (improved Japanese orthopaedic association, IJOA) score system. Independent sample t-test was performed for ages, preoperative IJOA scores, postoperative IJOA scores and IJOA difference values of the patients, and longitudinal extension of tumors in the two groups with congenital tumors and benign ependymomas. Two independent sample Mann-Whitney tests was performed for the patient's gender, stool and urine functions, limbs weakness, and tumor removed extent in the two groups. All patients were followed-up until June 30, 2009.

The average age of patients in congenital tumors group was 23.5+/-14.3, and in benign ependymomas group was 37.8+/-12.9, the age difference between the two groups was statistically significant (t=-2.89, P=0.007). The difference for location (Z=-3.59, P=0.001) and removed extent (Z=-2.89, P=0.004) of tumors between the two groups was statistically significant. Those located at the conus accounted for almost 83.3% (10/12) multi-segments intramedullary spinal cord congenital tumors. Because of the stiff adhesion with adjacent neural structures or penetrative growth in surrounding spinal marrow, some congenital tumors could not totally removed by force. The main purpose of surgery for these tumors was not total removal but decompression on the adjacent neural structures. Total or nearly total resection was achieved in 66.7% (8/12) patients diagnosed with congenital tumors. 78.9 (15/19) percent of multi-segments intramedullary spinal cord benign ependymomas were located at the cervical and cervicothoracic segments. Total or nearly total resection was achieved in 94.7% (18/19) patients with benign ependymomas.

It is known from the clinical files that most multi-segments intramedullary spinal cord congenital tumors are found in young patients and most benign ependymomas in the middle-aged. Most congenital tumors are located at the conus, and they are difficult to totally remove. Most benign ependymomas are located at the cervical and cervicothoracic segments, and they are easy to totally remove.