The Impact of Symptom Duration on Postoperative Outcomes in Patients Undergoing Anterior Cervical Discectomy and Fusion: A Systematic Review and Meta-Analysis.

Background And Context: The optimal timing at which patients should undergo Anterior Cervical Discectomy and Fusion (ACDF) surgery to achieve the best outcomes has not been determined. Given that patients may experience delays in care and that insurance companies often require a minimum of six weeks of conservative treatment before surgery, it is essential to determine the impact of symptom duration on outcomes following ACDF.

Purpose: To evaluate the impact of symptom duration on outcomes following ACDF surgery.

Study Design: Systematic review and meta-analysis.

Methods: Medline, Embase and Cochrane Library were searched from inception through July 2, 2024 in accordance with the PRISMA guidelines. Data on Neck Disability Index (NDI), Visual Analogue Scale (VAS) for neck and arm pain, and Short Form-12 (SF-12) physical and mental component scores were extracted. Subgroup analyses were performed to compare the outcomes at 6-months, 12-months and 24-months cutoff time points. Mean differences with 95%CI were used for continuous data.

Results: Nine studies comprising 1,511 patients (48.64% female) with a mean age of 50.56±9.88 years were included in this study. All patients achieved improvements in NDI, VAS, and SF-12 following ACDF. The amount of improvement decreased as symptom duration increased with patients experiencing greater than 24 months of symptoms experiencing statistically significantly less improvement in NDI (8.70 vs. 18.93, p=0.03), VAS Neck (1.95 vs. 3.33, p=0.003), and VAS Arm (1.74 vs. 3.72, p<0.001) in comparison to patients with less than 24 months of symptoms. There were no statistically significant differences in outcomes at the 6 and 12 months cut off points between cohorts.

Conclusion: Longer symptom duration is associated with worse outcomes compared to shorter symptom duration with statistically significant differences observed at the 24-month cutoff for NDI, VAS Arm, and VAS Neck scores. Patients with greater than 24 months of symptoms also failed to achieve clinically significant improvement in neck pain postoperatively. Given the lasting impact of disability and pain on patients, more studies should assess the impact of symptom duration on postoperative outcomes and at even shorter cut-off points.