The impact of operative level on patient-reported outcome measures following single-level posterior lumbar decompression for disc herniation.

Objective: To compare the impact of upper versus lower lumbar decompression on patient-reported outcome measures (PROMs).

Materials and methods: Patients undergoing L1-L2, L2-L3, L4-L5, or L5-S1 single-level elective decompression with 1-year PROMs were identified. Included PROMs were the Oswestry Disability Index (ODI), visual analog scale (VAS) back and leg, and Short Form-12 physical (PCS) and mental (MCS) component scores. Minimal clinically important differences (MCID) were calculated. Multivariable regressions assessed the independent predictive ability of operative level controlling for demographic confounders.

Results: Three hundred and forty-six patients were included (94 upper lumbar decompressions). Upper lumbar decompression patients were older (64.0 vs. 46.9, P < 0.001), had higher body mass index (BMI) (31.4 vs. 28.4, P < 0.001) and Charlson Comorbidity Index (CCI) (3.15 vs. 1.56, P < 0.001), and more commonly had diabetes (19.5% vs. 7.69%, P = 0.017). These patients had similar 1-year scores in ODI, VAS leg, and MCS but performed worse at 1 year in VAS back (3.58 vs. 2.75, P = 0.016) and at 6 months in ODI (24.5 vs. 17.9, P = 0.005) and were less likely to achieve MCID in PCS (48.8% vs. 64.4%, P = 0.041). However, multivariable regression did not identify upper lumbar decompression as independently associated with 1-year VAS back scores, 6-month ODI scores, or MCID achievement in PCS after controlling for age, BMI, diabetes, and CCI.

Conclusion: Patients undergoing upper lumbar decompression demonstrated worse PROMs. However, multivariable analyses suggested these differences were attributable to comorbidity burden and BMI, rather than operative level. This suggests that surgeons and patients can expect similar pain and function improvement from upper lumbar decompression when accounting for baseline patient characteristics.