New Scale Can Help Predict Poor Pain Control After Elective Spine Surgery

Researchers at the University of Calgary have developed and validated a clinical prediction scale that can be used to determine which patients are more likely to experience inadequate pain control following elective spine surgery. Armed with this knowledge, spine surgeons can ensure that patients obtain appropriate patient education and individualized clinical care with the goal of improved postoperative pain management.

For this study, the authors retrospectively reviewed data from 1300 adult patients who enrolled in the prospective Canadian Spine Outcomes and Research Network (CSORN) registry between August 28, 2014, and October 4, 2017. These patients had undergone elective spine surgery and required hospitalization for at least 24 hours postoperatively. The most common disorder was spinal stenosis (39%), and the most common complaint was radiculopathy (42%).

Postoperative pain was measured using an 11-point numerical scale, ranging from 0 = no pain to 10 = worst pain. Pain was assessed in the hospital while the patient was at rest; a pain level greater than 4 was considered poor pain control. During the first 24 hours following surgery, 57% of patients experienced poor pain control.

Patients were randomly assigned to 1 of 2 cohort groups:

  • Model development cohort to develop the prediction score for poor postoperative pain control (n=910)
  • Validation cohort to test whether the new scoring system fulfilled its purpose (n=390)

Data were examined to determine which patient variables are associated with poor pain control. Beginning with 25 variables, the authors narrowed the list to 7 variables that were independently predictive of poor postoperative pain control:

  • Younger age
  • Female sex
  • Higher preoperative neck or back pain score,
  • Preoperative daily use of opioid medication,
  • Surgery on 3 or more spinal motion segments,
  • Surgery involving fusion
  • Higher depression score on the Patient Health Questionnaire-9

They assigned clinical scores to each of these 7 predictors, with patients receiving a total clinical score between 0 and 13. This Calgary Postoperative Pain After Spine Surgery (CAPPS) score was consolidated first into an 8-tier risk classification and later collapsed into a 3-tier classification:

  • Low risk (scores 0-4)
  • High risk (scores 5-8)
  • Extreme risk (scores 9-13)

The performance of the CAPPS prediction scoring system was assessed by assigning prediction scores to the 390 patients in the validation cohort and then comparing the patients’ predicted pain control with their reported pain control.

The authors found that “predicted probabilities derived from both the 8-tier and 3-tier CAPPS score closely matched the incidence of poor pain control observed in the validation cohort.”

Using the 3-tier system, the low-, high-, and extreme-risk patient groups had 32%, 63%, and 85% predicted probabilities of experiencing inadequately controlled pain, respectively. These percentages are similar to the observed incidences of 37%, 62%, and 81%, respectively, for the same 3 groups of patients.

The authors conclude that the CAPPS predictive score “can be used to facilitate preoperative patient education and the development of personalized clinical care pathways to improve postoperative acute pain outcomes.”



Yang MMH, Riva-Cambrin J, Cunningham J, et al. Development and validation of a clinical prediction score for poor postoperative pain control following elective spine surgery. J Neurosurg Spine. 2020 Sep 15;1-10. doi: 10.3171/2020.5.SPINE20347. Online ahead of print.

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