Abstract / Summary
Study Design. Retrospective cohort study. Objective. To identify factors associated with the timing of bowel function recovery after separation surgery for metastatic spinal tumors, while incorporating the temporal dimension of postoperative rehabilitation Summary of Background Data. Separation surgery for metastatic spinal tumors is more extensive compared to conventional spinal surgery and carries a higher risk of postoperative ileus (POI). However, the factors influencing bowel recovery following this procedure remain poorly understood. Prior studies on conventional spinal decompression typically characterize bowel outcomes as binary events, neglect temporal recovery kinetics, and may introduce reverse causation bias. Methods. A retrospective analysis was conducted on patients who underwent separation surgery for metastatic spinal tumors at our institution (2021-2025). Clinical characteristics, postoperative ambulation status (including the status and time to first ambulation), and bowel movement outcomes (comprising the occurrence and postoperative time to first bowel movement) were collected. The primary endpoint was time to first postoperative bowel movement. Univariable and multivariable time-dependent Cox proportional hazards models were performed, with the time to first postoperative bowel movement serving as the primary outcome, and ambulation status modeled as a time-dependent covariate. Results. A total of 153 patients were included (median age 62 years [IQR, 57–69]; 64.7% male). During hospitalization, 134 patients (87.6%) achieved postoperative bowel movement, occurring at a mean of 4.0±1.9 days after surgery. In multivariable Cox regression analysis, postoperative ambulation was independently associated with earlier bowel recovery (HR, 5.69; 95% CI, 3.03–10.69; P <0.001), with the estimated association substantially increasing from HR 1.80 before adjustment for postoperative opioid consumption. Increasing age (per 10-year increase: HR, 0.83; 95% CI, 0.72–0.95; P =0.007) and greater postoperative 24-hour opioid consumption (per 10-MME increase: HR, 0.45; 95% CI, 0.35–0.57; P <0.001) were associated with delayed bowel recovery. Tumor origin, involvement pattern, ESCC grade, pathological fracture, surgical region, fixation levels, and decompression levels were not significantly associated with bowel recovery. Conclusion. Early postoperative ambulation was associated with faster bowel recovery after spinal tumor separation surgery, supporting its incorporation into postoperative rehabilitation strategies. Postoperative opioid management may require balancing adequate analgesia to facilitate mobilization against potential adverse effects on bowel recovery. Level of Evidence. Level III.