Effect of Postoperative Pain Control and Other Perioperative Risk Factors on Length of Stay after Elective Spine Surgery

Introduction: Prolonged length of stay (LOS) after elective spine surgery increases patients’ risk for in-hospital complications and contributes significantly to healthcare costs. While previous studies have examined the impact of various preoperative risk factors on LOS after spine surgery, the role of acute postoperative pain control and other postoperative factors has not been thoroughly explored.

Methods: Consecutive adult patients undergoing elective cervical or thoracolumbar spine surgery were enrolled. Baseline patient and surgical characteristics as well as intraoperative and postoperative complications were collected. The primary outcome was in-hospital LOS measured in days following surgery. The primary independent variable was poor pain control, defined as a mean numeric rating scale pain score of >4 during the first 24-hours postoperatively. Univariable analyses followed by multivariable regression analysis were used to investigate the relationship between poor pain control and LOS. Age and sex were forced into the multivariable model.

Results: 1305 patients were enrolled. Mean LOS was 4.38 days (standard deviation 8.18). Incidence of poor postoperative pain control was 56.9%. Multivariable analysis revealed poor pain control in the first 24-hours was significantly associated with increased LOS (p=0.03), after adjusting for other significant predictors which included perioperative hemodynamic instability (p=0.001), perioperative blood transfusion (p < 0.001), postoperative delirium (p < 0.001), postoperative day 1 morphine equivalent dose (p < 0.001), postoperative urinary tract infection (p < 0.001), postoperative urinary retention (p=0.003), postoperative surgical site infection (p < 0.001), postoperative wound complication (p < 0.001), postoperative neurologic deterioration (p < 0.001), surgical levels operated (p=0.016), operative time (p=0.007), ASA physical status score (p < 0.001), and preoperative disability score (p=0.001).

Conclusion : Poor pain control in the first 24-hours after elective spine surgery was an independent predictor of increased LOS. Our results also highlight that even minor complications like urinary issues and delirium can significantly impact LOS, therefore a proactive approach is necessary to address and prevent such complications.