Analysis of Outcomes Between Traditional Open versus Mini-Open Approach in Surgical Treatment of Spinal Metastasis

The treatment of spinal metastasis carries significant surgical morbidity, and decompression and stabilization are often necessary. Less invasive techniques may reduce risks and postoperative pain. This study describes the differences between a mini-open (MO) procedure and a traditional open surgery (OS) for symptomatic spinal metastasis, and reports differences in outcome for similar patients undergoing each procedure.

We describe a MO technique and retrospective analysis of 20 OS patients who were matched to 20 MO patients by histology, spinal region, and levels instrumented. MO surgery combined a traditional midline exposure for tumor resection with transfascial pedicle screw fixation. Outcome measures included estimated blood loss (EBL), operative time (OT), length of stay (LOS), transfusion rate, complication rate, ASIA Impairment Scale motor score (AMS), and pain scores. Statistical analysis used unpaired t tests and Fisher exact test.

Average age of the patients was 58.3 years. Forty-eight percent of patients were women. Average number of levels treated was 5.9. Both groups had similar LOS (P = 0.98), OT (P = 0.30), perioperative complication rates (P = 0.51), transfusion rates (P = 0.33), and AMS (P = 0.17). EBL was found to be significantly lower in the MO group than the open group (805 ± 138 mL vs. 1732 ± 359 mL, respectively; P = 0.019). The MO group had a significant reduction in postoperative pain (-1.71 ± 0.5 vs. 0.33 ± 0.7, P = 0.018).

Although further studies are needed, the MO approach appears to result in decreased blood loss and postoperative pain, without compromising neural element decompression or spinal stability. These findings are consistent with the use of muscle sparing, minimally invasive pedicle screw fixation.