The impact of prolapse to canal ratio (PCR) in cauda equina syndrome outcomes and operative management.

Purpose: This study aimed to evaluate the prolapse to canal ratio (PCR) and its long-term impact on outcomes in cauda equina syndrome (CES).

Methods: A 5-year retrospective cohort study was conducted across two neurosurgical centers, including adult patients diagnosed with CES due to herniated lumbar discs, treated with laminectomy and/or discectomy, with available radiological data and follow-up. PCR was calculated as the proportion of the disc prolapse cross-sectional area to the total spinal canal area. MRI scans were independently analyzed by two investigators, with random verification by a third. Patient demographics, symptoms, treatment, and follow-up data were also collected.

Results: Among 137 patients, cohorts were divided using a PCR cut-off of 0.5. Patients with PCR > 0.5 were significantly more likely to have persistent symptoms at follow-up (OR 3.93, CI 2.25-7.34, p < 0.0001). This risk increased with higher PCR thresholds (> 0.75 and > 0.8). PCR > 0.5 also predicted a greater likelihood of requiring a full laminectomy over minimally invasive approaches (OR 2.14, 95% CI 1.3-3.6, p < 0.005). Lower PCR (< 0.5) was associated with reduced complication rates and shorter hospital stays.

Conclusions: PCR is a valuable predictor of persistent pain and functional deficits following CES surgery and could be used to guide patient counseling before surgical intervention.