Disc-level predictors of indirect decompression of posterior cord compression by the ligamentum flavum following anterior cervical discectomy and fusion
摘要
Anterior cervical discectomy and fusion (ACDF) is commonly performed to treat cervical myelopathy. However, its effectiveness in decompressing posterior structures like hypertrophied ligamentum flavum, remains unclear. This study aimed to identify disc-level factors that predict radiographic improvement of posterior cord compression caused by ligamentum flavum (CCLF) after ACDF.
MethodsWe retrospectively analyzed 75 cervical disc levels from 43 patients who underwent ACDF for degenerative cervical disease with preoperative CCLF on MRI. Postoperative CCLF changes were evaluated, and discs were divided into improved and unimproved groups. Preoperative disc angle, segmental lordosis, disc height, preoperative disc range of motion, cage-to-disc ratio, Hounsfield units (HU) values, and facet joint degeneration were compared. Multivariate logistic regression was used to identify independent predictors of failure to improve CCLF.
ResultsPostoperative improvement in the CCLF was observed in 59 of 75 disc levels (79%). The unimproved group showed significantly larger preoperative disc angles (5.1° vs. 2.3°, p = 0.003) and higher HU values (368 vs. 326, p = 0.04). In addition, advanced facet osteoarthritis was significantly more frequent in the unimproved group (P = 0.027). Multivariate analysis demonstrated that greater preoperative disc angle (odds ratio [OR]: 1.21, 95% confidence interval [CI]: 1.01–1.45, p = 0.041), higher HU values (OR: 1.007, 95% CI: 1–1.015, p = 0.048) and advanced facet degeneration (OR = 8.92, 95% CI: 1.01–78.6, p = 0.049) were independently associated with failure to improve CCLF.
ConclusionIndirect decompression via ACDF may be less effective in segments with greater disc angles, higher bone densities, or advanced facet degeneration. These findings highlight the importance of preoperative disc-level assessment in surgical planning.