Comparing Spinal Cord Drift, Clinical Outcomes and C5 Palsy in Degenerative Cervical Myelopathy: A Study of Cervical Laminoplasty Versus Laminectomy/Fusion.

STUDY DESIGN: Retrospective comparative study.

OBJECTIVES: (i)to compare spinal cord drift between laminectomy and fusion(LF) and cervical laminoplasty(LP) for degenerative cervical myelopathy(DCM) treatment,(ii)to study relationship between preoperative cervical alignment, postoperative spinal cord drift, functional outcome, and C5 palsy.

METHODS: A cohort of 114 patients who underwent LP or LF for DCM were identified. After propensity-score matching, both groups included 30 patients each.Cobb angle(C2-C7) was used to assess pre-and postoperative cervical spine alignment(at 2-year follow-up).Based on alignment, there were lordotic(L) and straight(S) subgroups.Spinal cord position was measured on sagittal-and axial-T2W MRI of cervical spine pre-and postoperatively at 2-year follow-up and cord drift was measured by subtracting preoperative values from postoperative values.Functional recovery(mJOA score, mJOA recovery rate),and C5 palsy in patients were recorded and compared.

RESULTS: LF had higher mean spinal cord drift than LP(2.66 ± .77 vs 2.16 ± .80 mm, P = .049).Lordotic subgroups exhibited greater cord drift than straight subgroups within LP and LF groups.Both groups significantly improved mJOA scores at 2-year follow-up, with no LP-LF difference in mJOA recovery rate(mJOA-RR).Lordotic subgroups had significantly higher mJOA-RR(LP-L vs LP-S, P = .048; LF-L vs LF-S, P = .045).Preoperative cervical alignment, cord drift, and mJOA-RR correlated well(Spearman's ρ .7143 and .6053 respectively).Patients with >2.5 mm cord drift(n = 24) had significantly higher mJOA-RR as compared to <2.5 mm cord drift(n = 18). Substantial clinical difference was seen in C5 palsy risk between LP-S and LF-L, with the LF-L group having 3-fold higher risk.

CONCLUSION: LF had a biomechanical advantage in maximizing spinal cord drift in severe DCM cases, while both LP and LF showed significant improvements in neurological function. However, variability in C5 palsy rates highlights the need for individualized patient assessment.