Study Design. A retrospective review.
Objective. To evaluate the long-term clinical and radiological results after anterior microforaminotomy (AMF), with details of postoperative degeneration.
Summary of Background Data. AMF is an alternative procedure to treat unilateral cervical radiculopathy. Although previous clinical results are favorable, degeneration may occur after surgery. However, the details of this have not been proven.
Methods. A total of 154 AMF procedures in 135 patients were performed. Of these, 82 patients (97 AMF) had complete preoperative and minimum 3-year postoperative clinical outcomes data available for analysis. Radiological data were analyzed with picture achieving communication system images. Long-term clinical results were accessed by a questionnaire and telephone interviews. Clinical and radiological parameters were statistically analyzed.
Results. Spondylosis comprised 53.7%, disc herniation comprised 36%, and mixed comprised 10.3%. The mean age was 49 (range, 31–76) years. Operated levels were 1 level in 71 patients, 2 in 10, and 3 in 1. Reoperation was performed in 2 patients (2.4%). The mean follow-up was 6.1 years. A total of 90.3% achieved an excellent or good outcome. Visual analogue scale scores improved from 8.2 (6–10) to 2.9 (0–10), and neck disability index scores improved from 24.5 (7–46) to 6.7 (0–31) (P < 0.05). Eighty-one cases (83.5%) showed a decrease in disc height (DH), with 1 mm of the mean. The DH decrease was positively correlated with disc invasion (P < 0.01) and AMF diameter (P < 0.01). According to statistical analysis, the critical AMF diameter was 4.7 mm. Anterior spur formation occurred in 39 cases (40.2%). No radiological parameters affected the clinical outcome.
Conclusion. AMF is a safe, effective procedure to treat unilateral cervical radiculopathy. Critical DH decreases may be the trigger of sequential degeneration. To preserve DH, disc invasion must be avoided, and AMF must be made as small as possible with exact removal of compressive lesion.
Level of Evidence: 4