INTRODUCTION
Total en bloc spondylectomy (TES) is a surgery designed to achieve complete resection of spinal tumors. At our institution, we employ a combined approach at the level of L3-5 to preserve the lumbar nerves and to prevent injuries in major vessels. However, at the level of L1 and L2, we transect the nerve roots at the level of the tumor during dissection and resection of the vertebral body via a posterior approach. This study aimed to prospectively evaluate the lower limb motor function and walking ability after TES in the lumbar spine.
METHODS
We included patients who underwent TES for single-level lumbar spinal tumors at our institution between 2010 and 2021. Patients who were unable to walk due to neurologic symptoms prior to surgery were excluded from this study. We collected clinical data on age, sex, tumor histology, previous treatments, surgical approach, operating time, intraoperative bleeding, and postoperative complications. We prospectively assessed motor function and walking ability up to six months post-surgery. Lower extremity motor function was analyzed using manual muscle testing (MMT) of the iliopsoas, quadriceps, and tibialis anterior muscles. Postoperative muscle weakness was defined as a deterioration of at least one MMT score. We used the Spinal Cord Independent Measure indoor mobility item (SCIM item 12) to evaluate ambulation status. Measurements were taken before surgery, and at one, three, and six months postoperatively. Patient characteristics and functional outcomes were compared based on the levels of the resected vertebrae.
RESULTS
A total of 34 patients, with a mean age of 47.0 years at the time of surgery, were included in this study. Eight patients had primary tumors (3 osteosarcomas, 3 giant cell tumors, and 2 others), while 26 had metastatic tumors (14 from kidney cancer, 3 from breast, 3 from thyroid cancers, and 6 others). The levels of resected vertebrae included L1 in 8 cases, L2 in 6 cases, L3 in 9 cases, L4 in 5 cases, and L5 in 6 cases. Postoperative muscle weakness in the lower extremities was observed in 32 patients (94%), excluding 4 who underwent TES at L1. Severe weakness in the psoas or quadriceps muscles was noted in the patients who underwent TES at L3 or L4, though most regained normal strength within six months. Severe weakness in tibialis anterior muscle was observed in the patients who underwent TES at L5, with 2 patients (33%) experiencing significant weakness of the muscle and gait disturbance requiring a cane six months post-surgery. At one month post-surgery, ambulation status had deteriorated in 22 patients (65%). However, most patients regained normal walking ability within six months.
DISCUSSION
The incidence of postoperative motor dysfunction in the lower extremities after TES of the lumbar spine was high, particularly among the patients underwent who TES of the lower lumbar spine. However, walking ability normalized in most patients within six months post-surgery.