Postoperative function of lower extremity muscles and walking ability after total en bloc spondylectomy for lumbar spinal tumors.

Background Context: Total en bloc spondylectomy (TES) for lumbar tumors significantly impacts lower extremity motor function because of surgical stress on the lumbar nerve roots and psoas muscles.

Purpose: The aim of this study was to assess the strength of the major lower extremity muscles and walking function following lumbar TES using prospectively collected data and identify functional differences based on the levels of the resected vertebrae.

Study Design/setting: Retrospective study with prospectively collected data PATIENT SAMPLE: Data were collected from 34 patients who underwent single-level TES for lumbar spinal tumors at our institution between January 2010 and December 2021.

Outcome Measures: Lower extremity motor function and walking ability were evaluated pre- and post-surgery. Lower extremity motor function was analyzed using Manual Muscle Testing of the iliopsoas, quadriceps femoris, and tibialis anterior muscles at baseline and 1, 3, and 6 months post-surgery. The Spinal Cord Independent Measure indoor mobility was used to evaluate ambulation status at baseline and 1, 3, 6, and 12 months post-surgery.

Methods: In lumbar TES at our institution, L1 and L2 nerve roots were often transected while L3-L5 nerve roots were preserved. Dissection of the segmental vessels and detachment of the diaphragmatic crura via an anterior approach were often employed before posterior TES for L1-L3 lesions. Vertebral body resection and cage insertion via an anterior approach were performed following posterior element resection and instrumentation for L4 and L5 lesions.

Results: The incidence of postoperative lower extremity muscle weakness was 75% in the TES group at L1 and 100% at L2 or below. Quadriceps muscle weakness was most pronounced in patients who underwent L4-TES, involving wide dissection of the L3 and L4 nerve roots. Tibialis anterior muscle weakness was most severe in patients who underwent L5-TES with wide dissection of the L4 and 5 nerve roots. At 12 months post-surgery, walking ability normalized in all patients except some who underwent L4-TES or L5-TES.

Conclusion: Postoperative lower extremity muscle weakness was severe in patients undergoing TES involving the middle or lower lumbar spine. Patients who underwent L5-TES were more likely to experience residual gait disturbances.