Preservation of paraspinal muscle after transmuscular approach using a tubular retractor for lumbar decompression surgery

Objective: The objective of this study was to determine the outcome and the rate of paraspinal muscle preservation in patients who received decompression surgery with the transmuscular approach using a tubular retractor as compared to the conventional subperiosteal approach using a Caspar speculum. Materials and methods: Forty-one patients with lumbar disc herniation or lumbar spinal stenosis who received decompression surgery were reviewed from medical records. Tubular retractors (METRx MD large tube, 22 mm) were used in 19 patients (TR group), while a Caspar speculum was used in 22 patients (CS group). Clinical outcomes were assessed by JOA score. MR images were used to assessment of paraspinal muscle preservation after operation. Results: The preoperative JOA score in the TR group and the CS group was similar. The JOA score in both groups improved 1 year after operation. The preservation of paraspinal muscle was significantly greater in the TR group than the CS group (103 ± 10% and 89 ± 13%, respectively; P