Clinical effects and prognostic factors of combined laminoplasty with keyhole decompression for multilevel cervical spondylotic myelopathy: analysis based on cervical sagittal parameters

Expansive open-door laminoplasty is standard for multilevel cervical spondylotic myelopathy (MCSM), but suboptimal for concurrent radiculopathy. The clinical value of additional keyhole decompression and its impact on cervical sagittal alignment remain unclear. We hypothesized that combined laminoplasty with keyhole decompression would provide superior radicular symptom relief compared to laminoplasty alone in MCSM patients with varying radicular severity, while maintaining sagittal alignment, with surgical technique, disease duration, and nerve root compression severity as independent prognostic factors. This study evaluates clinical outcomes, sagittal parameters, and prognostic factors. Retrospective analysis of 94 MCSM patients (January 2021-December 2022): 34 combined group, 60 laminoplasty group. Outcomes (JOA, NDI, VAS) and sagittal parameters assessed preoperatively, 1-month, and 1-year postoperatively. Propensity score matching (PSM) addressed selection bias; multivariate regression identified predictors. JOA improvement rates comparable (combined: 47.8 ± 12.4% vs. laminoplasty: 46.2 ± 11.8%, P > 0.05). Combined group showed superior NDI (15.2 ± 5.4% vs. 18.6 ± 5.8%, P = 0.008, Cohen’s d = 0.61) and VAS (1.0 ± 0.6 vs. 2.2 ± 0.8, P < 0.001, d = 1.68) improvements. Post-PSM results consistent. Sagittal changes (decreased C2-C7 Cobb, increased cSVA/T1 slope, P < 0.05) similar between groups. Predictors: surgical technique (β = 0.386, P = 0.008), disease duration (β=-0.312, P = 0.006), compression severity (β = 0.368, P = 0.010; GRADE: moderate-high evidence). Combined approach offers superior radicular relief without compromising alignment or neurological recovery. Evidence-based patient stratification and prognostic modeling advance personalized MCSM management; future RCTs needed to validate.