The Calgary Postoperative Pain after Spine Surgery (CAPPS) score was developed to identify patients at risk of experiencing poorly controlled pain after spine surgery. The goal of this study was to independently validate the CAPPS score on a prospectively collected patient sample.

Poor postoperative pain control was defined as a mean numeric rating scale (NRS) for pain >4 at rest in the first 24 hours after surgery. Baseline characteristics in this study (validation cohort) were compared to those of the development cohort used to create the CAPPS score. Predictive performance of the CAPPS score was assessed by the area under the curve (AUC) and percentage misclassification for discrimination. A graphical comparison between predicted probability vs. observed incidence of poorly controlled pain was performed for calibration.

Fifty-two percent of 201 patients experienced poorly controlled pain. The validation cohort exhibited lower depression scores and a higher proportion using daily opioid medications compared to the development cohort. The AUC was 0.74 [95%CI = 0.68–0.81] in the validation cohort compared to 0.73 [95%CI = 0.69–0.76] in the development cohort for the eight-tier CAPPS score. When stratified between the low- vs. extreme-risk and low- vs. high-risk groups, the percentage misclassification was 21.2% and 30.7% in the validation cohort, compared to 29.9% and 38.0% in the development cohort, respectively. The predicted probability closely mirrored the observed incidence of poor pain control across all scores.

The CAPPS score, based on seven easily obtained and reliable prognostic variables, was validated using a prospectively collected, independent sample of patients.

The expansion of age-related degenerative spine pathologies has led to increased referrals to spine surgeons. However, the majority of patients referred for surgical consultation do not need surgery, leading to inefficient use of healthcare resources. This study aims to elucidate preoperative patient variables that are predictive of patients being offered spine surgery.

We conducted an observational cohort study on patients referred to our institution between May 2013 and January 2015. Patients completed a detailed preclinic questionnaire on items such as history of presenting illness, quality-of-life questionnaires, and past medical history. The primary end point was whether surgery was offered. A multivariable logistical regression using the random forest method was used to determine the odds of being offered surgery based on preoperative patient variables.

An analysis of 1194 patients found that preoperative patient variables that reduced the odds of surgery being offered include mild pain (odds ratio [OR] 0.37, p=0.008), normal walking distance (OR 0.51, p=0.007), and normal sitting tolerance (OR 0.58, p=0.01). Factors that increased the odds of surgery include radiculopathy (OR 2.0, p=0.001), patient’s belief that they should have surgery (OR 1.9, p=0.003), walking distance <50 ft (OR 1.9, p=0.01), relief of symptoms when bending forward (OR 1.7, p=0.008) and sitting (OR 1.6, p=0.009), works more slowly (OR 1.6 p=0.01), aggravation of symptoms by Valsalva (OR 1.4, p=0.03), and pain affecting sitting/standing (OR 1.1, p=0.001).

We identified 11 preoperative variables that were predictive of whether patients were offered surgery, which are important factors to consider when screening outpatient spine referrals.