Impact of Preoperative Intervertebral Disc Degeneration on Patient-Reported Outcome Measures After Lumbar Fusion

The Pfirrmann scoring system classifies lumbosacral disc degeneration based on magnetic resonance imaging signal intensity. The relationship between pre-existing disc degeneration and patient-reported outcome measures (PROMs) after one-level lumbar fusion is not well documented. The purpose of this study was to investigate the relationship between the severity of preoperative intervertebral disc degeneration and preoperative and postoperative PROMs in patients undergoing one-level lumbar fusion.

All adult patients who underwent posterior lumbar decompression and fusion or transforaminal lumbar interbody fusion between 2014 and 2022 were included. Patient demographics and comorbidities were extracted from medical records. Lumbar intervertebral discs on sagittal magnetic resonance imaging T2-weighted images were assessed by 2 independent graders utilizing Pfirrmann criteria. Grades I-III were categorized as low-grade disc degeneration, while IV-V were considered high grade. Multivariable linear regression assessed the impact of disc degeneration on PROMs.

A total of 150 patients were included, of which 69 (46%) had low-grade disc degeneration, while 81 (54%) had high-grade degeneration. Patients with high-grade degeneration had increased preoperative visual analog scale (VAS)-Leg scores (6.10 vs. 4.54, P = 0.005) and displayed greater 1-year postoperative improvements in VAS-Back scores (-2.11 vs. -0.66, P = 0.002). Multivariable regression demonstrated Pfirrmann scores as independent predictors for both preoperative VAS-Leg scores (P = 0.004) and postoperative VAS-Back improvement (P = 0.005).

In patients undergoing one-level lumbar fusion, higher Pfirmann scores were associated with increased preoperative leg pain and greater 1-year postoperative improvement in back pain. Further studies into the relationship of preoperative disc degeneration and their impact on postoperative outcomes may help guide clinical decision-making and patient expectations.