Validation of current procedural terminology codes for surgical stabilization of rib fractures

Current procedural terminology (CPT) codes for surgical stabilization of rib fractures (SSRF) are based solely on the number of ribs fixed, tricotomized at 1-3, 4-6, and ≥ 7. Our objective was to validate CPT codes against operative time at our institution, as well as further stratify complexity by rib fracture location and surgical approach. The purpose of this study is to validate the current CPT coding schema for SSRF, and to identify potential modifiers that are associated with increased case complexity. We hypothesized that operative time is associated with CPT code, number of fractures repaired, exposure technique, and fracture location.

Retrospective review of SSRF cases from October 2010 to March 2020. The primary outcome was the length of the operation (minutes). Predictor variables were CPT code, number of fractures repaired (grouped similarly to CPT codes), fractures repaired:ribs repaired ratio > 1, fracture location (sub-scapular vs. other), and positioning/exposure (supine, lateral, prone, and multiple). Kaplan-Meier time-to-event analyses were used to assess relationship with operative time.

188 patients underwent repair of 904 fractures. Operative time was significantly associated with both number of ribs repaired and number of fractures repaired (p<0.01). Although operative time varied significantly by CPT group (p<0.01), there was no significant difference between the 4-6 rib and the ≥ 7 rib groups (p = 0.33). By contrast, each group was significantly different from the others when organized by number of fractures repaired (p = 0.04). Operative time was significantly longer when the fractures repaired:ribs repaired ratio was > 1 (p<0.01), even after stratifying by number of ribs repaired. Both multiple positions/exposures (p<0.01), and repair of ≥ 1 sub-scapular fracture (p<0.01) were significantly associated with operative time.

Number of fractures repaired provided a more accurate estimation of operative time as compared to number of ribs repaired. Based on these data, we recommend altering the CPT schema for SSRF to involve number of fractures repaired, with modifiers for both multiple positions/exposures and repair of sub-scapular fractures.