Does Posterior Cord Compression From the Ligamentum Flavum Influence Clinical Outcomes After Anterior Cervical Discectomy and Fusion?

Abstract

Study design: Retrospective cohort study Objective: To clarify whether outcomes of anterior cervical discectomy and fusion (ACDF) differ according to presence of posterior cord compression from the ligamentum flavum (CCLF) Summary of background data: Although ACDF effectively addresses anterior cord compression from disc material and bone spurs, it cannot address posterior compression. Whether ACDF could result in favorable outcomes when CCLF is present remains unclear. Methods: A total of 195 consecutive patients who underwent ACDF and were followed-up for >2 years were included. CCLF was graded based on MRI findings. Patients with CCLF grade 2 were classified as such, while patients with CCLF grade 0-1 were classified as the no-CCLF group. Patient characteristics, cervical sagittal parameters, neck pain visual analogue scale (VAS), arm pain VAS, and Japanese Orthopedic Association (JOA) score were assessed. Categorical variables were analyzed using a chi-square test, while continuous variables were analyzed using the Student’s t-test. Multivariable logistic regression analysis was performed to elucidate factors associated with JOA recovery rates of >50%. Results: One-hundred and sixty-seven patients (85.6%) were included in the no-CCLF group, while the remaining 28 patients (14.4%) were included in the CCLF group. Among patients in the CCLF group, 14 patients (50.0%) achieved clinical improvement. JOA score significantly improved in the no-CCLF group after the operation (P<0.001) while improvement was not appreciated in the CCLF group (P=0.642). JOA score at 3 months (P=0.037) and 2 years (P=0.001) postoperatively were significantly higher in the no-CCLF group. Furthermore, the JOA recovery rate at 2 years after surgery was significantly higher in the no-CCLF group (P=0.042). Logistic regression demonstrated that CCLF was significantly associated with a JOA recovery rate of >50% at 2 years following surgery (OR 2.719; 95% CI 1.12, 6.60). Conclusion: ACDF performed for patients with CCLF grade 2 showed inferior JOA score improvement compared to those with CCLF grade 0 or 1. ACDF cannot remove posterior compressive structures, which limits its utility when ligamentum flavum significantly contributes to cord compression.

Failure of Surgical Equipoise in Posterior Cord Syndrome Myelopathy

“…[7][8][9] Literature on the surgical care of CSM does not commonly differentiate the outcome by the cord syndrome involved, and so at the current state of practice evidence, it remains professionally acceptable to treat a posterior cord syndrome anteriorly. 10,11 A recent publication from Korea 12 found that posterior indentations of the cord from ligamentum flavum hypertrophy were not consistently relieved by anterior surgery and so that pathoanatomy argues for a posterior approach.…”

“…A recent publication from Korea 12 found that posterior indentations of the cord from ligamentum flavum hypertrophy were not consistently relieved by anterior surgery and so that pathoanatomy argues for a posterior approach.…”