The association of preoperative hemoglobin a1c with the resolution of spinal cord high-intensity signals after anterior cervical surgery

Cervical Spondylotic Myelopathy (CSM) is a degenerative spinal condition resulting from cervical cord compression, often manifesting as intramedullary hyperintensity on T2-weighted MRI (HCS), reflecting chronic ischemic injury. Although anterior cervical surgery achieves cord decompression, neurological recovery remains inconsistent, particularly in patients with diabetes mellitus (DM), which may impair microvascular integrity and neural repair. Glycated hemoglobin (HbA1c) is an established marker of chronic glycemic control, yet its relationship with postoperative HCS resolution in diabetic CSM patients is unclear.This single-center retrospective study enrolled diabetic CSM patients undergoing anterior cervical decompression and fusion (January 2016–January 2022) by a single surgeon. Inclusion required preoperative HCS (Spinal Cord Ratio, SCR≥1.23), and available preoperative, 6-month, and 24-month MRI and clinical follow-up. Exclusions comprised prior cervical surgery, trauma, infection, or tumor. Primary outcomes were HCS resolution, quantified as Cord Resolution ratio at 6 (CR1) and 24 months (CR2), and clinical improvement via JOA score recovery rates (Recovery1, Recovery2). Preoperative HbA1c was the independent variable; covariates included demographics, comorbidities, and radiographic parameters. Reliability of imaging measures was assessed with ICC. Multivariate linear regression identified predictors of outcomes. Patients were stratified by 24-month HCS improvement into “Good” (CR2≥0.15) vs. “Poor” recovery groups. Binary logistic regression and ROC analyses determined risk factors and optimal HbA1c cutoff.Mean preoperative HbA1c was 8.3%–3.7%. Higher HbA1c independently predicted poorer 24-month HCS resolution (CR2: β=–0.108, P=0.003) and inferior clinical recovery (Recovery2: P=0.046), but not 6-month outcomes. HbA1c was an independent risk factor for poor 24-month recovery (OR=0.401, P=0.026). ROC analysis indicated HbA1c optimally predicted HCS recovery (AUC=0.715), with ≤6.8% cutoff yielding 71.4% sensitivity and 76.0% specificity.Preoperative HbA1c significantly predicts long-term HCS resolution and neurological outcome in diabetic CSM patients after anterior cervical surgery. Targeting HbA1c ≤6.8% may optimize recovery, underscoring the importance of perioperative glycemic control.