Paravertebral muscle quality and adjacent facet joint degeneration as significant predictors of ASDis revision after lumbar fusion

BACKGROUND: Posterior lumbar interbody fusion (PLIF) combined with pedicle screw internal fixation is widely used to treat lumbar degenerative diseases. However, adjacent segment disease (ASDis) is a severe complication and requires revision surgery, and few studies have focused on this complication. Paravertebral muscle quality loss is associated with the occurrence of lumbar diseases and poor postoperative prognosis, but its relationship with ASDis revision remains unclear. PURPOSE: To explore the relationship between paravertebral muscle quality and ASDis revision after lumbar fusion and identify its independent risk factors. METHODS: Patients who underwent revision surgery for ASDis at our hospital were enrolled. To evaluate the risk factors for revision, we selected a control group. Each patient in the control group was matched by age, sex, height, weight, BMI, number of fused segments and follow-up duration with a patient in the revision group. Paravertebral muscle parameters, including the cross-sectional area (CSA), functional cross-sectional area (FCSA), CSA-vertebral index (CSA-VI), FCSA-vertebral index (FCSA-VI), and FCSA/CSA ratio, were measured at the third lumbar (L3) and fourth lumbar (L4) levels via MRI. Receiver operating characteristic (ROC) curves and logistic regression were used for analysis. RESULTS: At the L3 and L4 levels, the FCSA, FCSA-VI and FCSA/CSA ratio of the paraspinal muscle, erector spinae and multifidus were significantly lower in the revision group (P < 0.05). The L4 paravertebral muscle FCSA/CSA ratio had the highest area under the curve (AUC) value (0.942). Preoperative adjacent facet joint degeneration was greater in the revision group (P < 0.05). Logistic regression revealed that the L4 paravertebral muscle FCSA/CSA ratio (odds ratio = 0.731; P < 0.001) and preoperative adjacent facet joint degeneration (odds ratio = 4.664; P = 0.023) were independent risk factors. CONCLUSION: Decreased paravertebral muscle quality is associated with an increased incidence of ASDis revision. L4 paravertebral muscle FCSA/CSA and preoperative adjacent facet joint degeneration can predict whether revision surgery is needed for patients with ASDis.