Factors affecting functional outcome after anterior cervical discectomy and fusion: A multicenter study.

Background Although anterior cervical discectomy and fusion (ACDF) represents a standardized procedure for surgical treatment of a cervical herniated disc, several variables could affect patients' clinical and radiological outcome. We evaluated the impact of sex, age, body mass index (BMI), myelopathy, one- or two-level ACDF, and the use of postoperative collars on functional and radiological outcomes in a large series of patients operated for ACDF. Materials and Methods Databases of three institutions were searched, resulting in the enrollment of 234 patients submitted to one- or two-level ACDF from January 2013 to December 2017 and followed as outpatients at 6- and 12-month follow-up. The impact of variables on functional and radiological outcomes was evaluated using univariate and multivariate logistic regression analysis. Results At univariate analysis, female sex, higher BMI, two-level ACDF, and postoperative collar correlated with a significantly worse early and late Neck Disability Index (NDI). Multivariate analysis showed that male patients had a lower risk of worse early (P = 0.01) and late NDIs (P = 0.009). Patients with myelopathy showed better early NDI (P = 0.004). Cervical collar negatively influenced both early and late NDIs (P < 0.0001), with a higher risk of early nonfusion (P = 0.001) but a lower risk of late nonfusion (P = 0.01). Patients operated for two-level ACDF have a worse early NDI (P = 0.005), a worse late NDI (P = 0.01), and a higher risk of early nonfusion (P = 0.048). BMI and age did not influence outcome. Conclusions Female sex, two-level surgery, and the use of postoperative collars significantly correlate with worse functional outcomes after one- or two-level ACDF.