Long-term Follow-up Results of Anterior Cervical Microforaminotomy

Jung, Sung Sam; Chung, Jong Chul; Park, Ki Seok; Chung, Seung Young; Park, Moon Sun; Ha, Ho Gyun

Abstract

OBJECTIVE
We previously reported excellent early and midterm clinical results of anterior cervical microforaminotomy (ACMF) for patients with cervical radiculopathy caused by disc herniation or foraminal stenosis. ACMF is accepted as a minimally invasive functional spinal surgery, but its long-term outcomes are unknown. The purpose of this study is to evaluate the long-term clinical and radiographic results of ACMF.
METHODS
We performed a questionnaire survey and retrospective analysis of 13 patients with cervical radiculopathy who underwent ACMF from 1998 to 2002. Clinical and radiographic data from these 13 patients (one-level operations in seven patients, and two-level operations in six patients) were analysed. We measured disc height, sagittal plane displacement and sagittal plane angulation to evaluate instability.
RESULTS
Thirteen patients answered the questionnaires. Mean follow-up was 77.3 months (ranged from 498 to 110 months). The surgical outcome was excellent in three patients (23%) and good in nine patients (69%). One patient had only a fair outcome, but there were no cases of recurrence, reoperation or additional surgery. Twelve of 13 patients were satisfied with the results of their surgery. On the average, the loss of disc height was 0.84mm(16.6% of preoperative disc height), increase of displacement was 0.47mm and increase of sagittal plane angulation was 0.65degrees. All patients maintained stability during the follow-up period. Although the patient sample included in this study is a different sample from that surveyed in our previous study of mid-term results, the long-term radiographic outcomes showed that the parameters of instability tended to decrease in comparison to those midterm results. Three-dimensional computed tomography scans showed signs indicative of bone remodeling, including regrowth of the resected bone and gradual fusion around the uncovertebral joint (UVJ) where ACMF was performed. In spite of bone regeneration around the UVJ, the neural foramen appeared to be well maintained in all patients.
CONCLUSION
In the long-term, ACMF is clinically effective method for the treatment of cervical radiculopathy, although disc height was decreased and sagittal angulation was increased. UVJ with mild hypermobility that was apparent at midterm appears to be restored during long-term follow-up. The efficacy of this procedure should be evaluated in additional studies involving large patient series.