Association Between Early Postoperative Pain Burden and 30-Day Health-Related Quality of Life After Lumbar Spinal Fusion: A Multicenter Prospective Cohort Study.

PURPOSE: The relationship between early postoperative pain burden, quantified by the area under the pain score-time curve (AUC), and the recovery of health-related quality of life (HRQoL) after lumbar spinal fusion remains unclear. This study examined whether cumulative pain burden during the first postoperative week was independently associated with HRQoL at postoperative day (POD) 30. METHODS: This secondary analysis of a multicenter prospective cohort included 158 adults undergoing lumbar spinal fusion. HRQoL was assessed using the EQ-5D questionnaire at baseline and on POD 1, 3, 7, 14, 21, and 30. Pain intensity over the last 24 hours was assessed on POD 1, 3, and 7 using questions adapted from the Brief Pain Inventory. Early postoperative pain burden was quantified as the area under the pain score-time curve over POD 1, 3, and 7 using the trapezoidal method. The primary outcome was the EQ-5D index on POD 30. RESULTS: The median baseline EQ-5D index was 0.82 (interquartile range [IQR], 0.58 to 0.89). On POD 1, it declined to 0.05 (IQR, -0.02 to 0.11) and gradually recovered to 0.85 (IQR, 0.69 to 1.00) by POD 30. Median pain burden AUC was 17 (IQR, 11 to 22). Patients with higher pain burden demonstrated worse recovery trajectories and significantly lower EQ-5D on POD 30 (mean difference 0.18; 95% CI, 0.09 to 0.26; P < 0.001), and higher incidence of pain on POD 30 (65.7% vs 27.3%, P < 0.001). In multivariable analysis, early pain burden remained independently associated with poorer HRQoL (β = -0.007 per unit increase; 95% CI, -0.012 to -0.002; P = 0.005), along with hypoalbuminemia (β = -0.252; 95% CI, -0.368 to -0.135; P < 0.001) and longer surgical duration (β = -0.038 per hour increase; 95% CI, -0.066 to -0.011; P = 0.007). High pain burden also independently associated with pain presence on POD 30 (OR= 1.095; 95% CI, 1.040 to 1.153; P = 0.001). CONCLUSION: Cumulative early postoperative pain burden independently predicts delayed HRQoL recovery at 30 days after lumbar spinal fusion, highlighting early pain management as a potentially modifiable target to improve postoperative recovery.