The Impact of Pre-Operative Physical Therapy on Outcomes of Lumbar Disc Herniation Surgery: A Retrospective Cohort Study using a National Research Network

Introduction: Despite being the most common surgical intervention for leg and back pain with more than 300,000 cases performed annually in the U.S., 25 –33% of patients report poor outcomes from discectomy for Lumbar Disc Herniation (LDH).1 2 3 In a recent retrospective case control study, we identified a significant correlation between pre-operative physical therapy (PT) and sub-optimal surgical outcomes. Here, we studied this relationship using patients from a national research network.

Methods: The TriNetX U.S. Collaborative Network was queried for adults ≥1 8 years that underwent primary lumbar discectomy for treatment of LDH within the past 20 years. The patients were sorted into two cohorts: (1) underwent PT motor treatment, and (2) did not undergo any PT treatment or assessment within 1 year prior to surgery. Confounding variables associated with surgical outcomes were accounted for with propensity matching. Comparative analysis was performed for outcomes at 1-3 years post-op as defined by residual symptoms or continued use of medications for pain control.

Results: The propensity-matched cohorts each included 325 patients. Those that underwent PT had risk ratios of 2.375 for neurologic deficit (motor and sensory deficit combined; P< 0.001), 2.3 for motor deficit alone (P=0.02), and 2.529 for sensory deficit alone (P < 0.001). Patients who underwent PT demonstrated risk ratios of 1.375 for opiates (P < 0.001), 1.556 for nerve pain agents (P=0.004), 1.441 for muscle relaxants (P=0.014), and 1.362 for use of any of these medications (P < 0.001). Radiculopathy (P=0.13) and continued use of NSAIDs (P=0.14) were not associated with pre-operative PT.

Conclusion : These results provide evidence that pre-operative PT may present a risk for poor surgical outcomes. We hypothesize that PT can aggravate compressed nerve roots in candidates who could benefit from surgical intervention. Thus, although PT may benefit patients suffering from musculoskeletal pain secondary to disk herniation, it could cause nerve root irritation in the setting of symptomatic LDH.