Predictive Factors for Outcomes Following Surgical Treatment of Lumbar Disc Herniation

Introduction: Lumbar Disc Herniation (LDH) is a common cause of radicular pain with an annual incidence between 5 and 20 cases per 1000 adults. LDH is typically treated by microdiscectomy, of which more than 300,000 are performed in the U.S. each year. Despite this frequency, 25-33% of patients report poor surgical outcomes.

Methods: A retrospective study of 241 patients at Stony Brook Medicine from 2017-2022 was performed, 118 of which were included for final analysis. The mean time to follow up was 366 days with all patients followed for at least 90 days. Data collection included demographics, medical/surgical history, and surgical methodology. Good outcomes were defined as meeting the Minimum Clinically Important Difference (MCID) - 3.5pt reduction in pain reported by Numerical Rating System (NRS) or resolution of either radicular pain or neurologic symptoms.

Results: Univariate analysis revealed that 92.3% of patients with prior spine surgery (P=0.006), 100% of those with prior fusions (P=0.019, N=98), and 73.2% who underwent pre-operative physical therapy (PT) (P=0.011) failed to meet the MCID. Additionally, 79.1% (P=0.019,) and 82.8% (P=0.015) of patients who had PT, had residual radicular pain and neurologic symptoms, respectively. Multivariate logistic regression confirmed correlations between pre-operative PT and failure to meet the MCID (P=0.016, OR=0.217), and resolution of radicular (P=0.012, OR=0.280) and neurologic (P=0.038, OR=0.287) complaints. MCID also significantly correlated with higher pre-operative NRS scores in both univariate (P=0.0002, N=98) and multivariate (P=0.001, OR=1.652) analyses.

Conclusion : The results of our retrospective analysis show that higher preoperative NRS scores, pre-operative PT, and prior spine surgery, are associated with outcomes. While PT is considered a viable non-operative treatment for LDH, our findings suggest detrimental effects when preceding surgery. Patients with higher NRS pain scores also were more likely to have improvement after surgery.