Anterior cervical decompression improves medial plantar pressure in OPLL with gait disturbance: a 24-month...

Ossification of the posterior longitudinal ligament (OPLL) is a major cause of degenerative cervical myelopathy. Whether surgical approach differentially affects lower-limb sensorimotor function is unclear. We linked radiological markers of cord injury with gait biomechanics to compare anterior versus posterior decompression.

Retrospective cohort (single tertiary center, 12/2018-12/2022). Adults with cervical OPLL, gait disturbance, and focal intramedullary T2 hyperintensity (signal change ratio [SCR] ≥ 1.20) were included. Patients underwent anterior (ACDF/ACCF/hybrid) or posterior (laminoplasty/laminectomy-fusion) decompression. The primary endpoint was the 24-month change in medial foot pressure (MFP), the percentage of total plantar load borne by a pre-defined medial mask (first-third metatarsal heads plus the medial heel). Secondary endpoints included MFP at 6 months; SCR regression at 6 and 24 months (CR1, CR2); and the Japanese Orthopaedic Association (JOA) score.

t-tests for group comparisons; linear regression for ΔMFP_24mo (absolute change in percentage points) with covariate adjustment.

Sixty-three patients were analyzed (anterior = 34; posterior = 29). Baseline demographics and imaging (SCR, CNR, C2-7 Cobb, SVA, modified K-line interval [mK-line INT]) were similar between groups. Preoperative MFP did not differ (52.6 ± 7.4% vs 52.9 ± 7.6%). At 6 months, both groups improved without between-group difference (49.4 ± 6.8% vs 49.8 ± 6.9%). At 24 months, the anterior group showed larger MFP reduction (46.1 ± 6.0% vs 50.6 ± 6.4%). JOA improvement favored anterior surgery (14.1 ± 1.0 vs 12.6 ± 2.1; p = 0.001), as did regression of T2 hyperintensity (CR2 0.22 ± 0.14 vs - 0.01 ± 0.24; p = 0.001). In multivariable analysis, anterior approach independently predicted greater ΔMFP_24mo (β =  + 3.9%, 95% CI + 1.8 to + 6.0; p = 0.001), alongside preoperative SCR (β =  + 1.4%, p = 0.006) and preoperative MFP (β =  + 0.22% per baseline %, p = 0.012). Sensitivity analyses (complete-case; extended covariate adjustment) were consistent.

In OPLL myelopathy with focal T2 hyperintensity, direct ventral (anterior) decompression was associated with a more durable 24-month reduction in medialized plantar loading than posterior indirect decompression, with aligned improvements in MRI signal and JOA.