Radiological and Clinical Outcomes of Anterior Cervical Discectomy and Fusion in Older Patients: A Comparative Analysis of Young-Old Patients (Ages 65-74 Years) and Middle-Old Patients (Over 75 Years)

Objective: Anterior cervical discectomy and fusion (ACDF) is the most commonly performed procedure for degenerative cervical spondylosis. Because of its relatively low invasiveness and surgical procedure, old age is not regarded as an exclusion criterion for ACDF. However, very few studies have been conducted on the radiological and clinical outcomes of ACDF in older patients. The purpose of this study was to evaluate the radiological and clinical outcomes of ACDF in older patients. Methods: We retrospectively analyzed 48 patients (> 65 years) who underwent ACDF from January 2011 to December 2015. We divided the patients into 2 groups: young-old age group (65-74 years) and middle-old age group (>= 75 years). Cervical lateral radiographs taken in the neutral standing position were evaluated preoperatively (PRE), on postoperative day 7 (POST), and at the 1-year follow-up (F/U). The radiological parameters included cervical angle (CA: C2-7 Cobb angle), segmental angle, total intervertebral height, disc height, sagittal vertical axis (SVA), T1 slope (T1s), and range of cervical motion (extension CA minus flexion CA). Postoperative hospital days, comorbidities, complications, and clinical outcomes were also analyzed. Results: We analyzed data from 48 patients (group A: n = 30 patients, 46 segments, mean age, 68.60 +/- 3.36 years; group B: n= 18 patients, 23 segments, mean age, 79.22 +/- 2.63 years). The surgical levels were as follows: C3/4, 4; C4/5, 7; C5/6, 10; C6/7, 29; and C7/T1, 6 levels, and there were no significant between-group differences in the distribution. There were no significant between-group differences in the fusion and subsidence rates (fusion rate: group A, 76.2%; group B, 71.4%; p = 0.732; subsidence rate: group A, 34.8%; group B, 26.1%; p = 0.587). There was no longitudinal trend in the repeated-measurements analysis of variance test of the 2 groups of the PRE, POST, and F/U data for each radiological parameter. According to the paired t-test, T1 slope (T1s), SVA, and CA did not differ preoperatively and postoperatively. There was no statistically significant difference in visual analogue scale scores (axial, arm), the Neck Disability Index, or Odom's criteria between the 2 groups (p = 0.448, p = 0.357, and p = 0.913). Conclusion: There was no significant difference in radiological and clinical outcomes between young-old and middle-old patients. Middle-old age does not seem to be a limitation to ACDF, but larger-scale and longer-term studies are needed to confirm the findings of this study.