LAUSR

BACKGROUND Separation surgery is performed to provide a safe gap between the epidural tumor and spinal cord for postoperative stereotactic body radiotherapy (SBRT) in cases of spinal metastases. However, there is a gap in evidence regarding sufficient tumor resection in separation surgery. We aimed to describe the prognoses according to the extent of resection in separation surgery. METHODS This retrospective study included 36 consecutive patients who underwent separation surgery and postoperative SBRT between December 2016 and December 2019 at a single center. Local control (LC), overall survival (OS), distance of separation (DS), and quality of life parameters were analyzed. P-values <0.05 were considered statistically significant. RESULTS Patients were assigned to the aggressive resection (ARG, n=18) or moderate resection (MRG, n=18) groups, with estimated LC and OS at 1 year of 79.0% and 75.9%, respectively. There were no significant differences between ARG and MRG in estimated LC (85.9% vs. 72.2%, P=0.317) or OS (69.3% vs. 80.9%, P=0.953) at 1 year. All 5 patients in MRG who developed local progression had less satisfactory tumor resection with DS <3 mm. A borderline significant difference in estimated LC at 1 year was noted between individuals with DS <3 mm and those with DS ≥3 mm (51.9% vs. 100.0%, P=0.053) in MRG. There was no statistical difference between ARG and MRG in quality of life parameters. CONCLUSIONS Moderate resection of ventral dural mass didn't significantly reduce patients' prognosis in separation surgery. However, the minimal distance between the postoperative residual epidural tumor and spinal cord should be ≥3 mm.