M. Tschigrjai, F. Weber
Klinikum Saarbrucken, Saarbrucken, Germany
Objective: The purpose of this study is to compare the patients outcomes after functional intervertebral cervical disc prosthesis and after anterior fusion according the provide relief from objective neurological symptoms and signs, improve patient function, decrease pain, and provide motion.
Materials and Methods. For this purpose, 30 patients( 10 patients with cervical disc prosthesis, 10 patients with cage fusion and 10 patients with pallacos "fusion") were assessed pre-op, post-op, 6 weeks, 3 months, 6 months, 1 year. Patient inclusion criteria consisted of disc herniation or spondylosis, with radiculopathy and/ or myelopathy, which had not responded to conservative treatment. Exclusion criteria included previous cervical spine surgery involving any other device, axial neck pain as the solitary symptom, significant cervical anatomical deformity or clinical instability, and active infection. Patient data was entered into a database. Results were scored according to a modified Odom's Criteria, based on relief of preoperative symptoms and relief of objective neurological signs (as assessed by the physician in a neurological examination) associated with the treated level. Radiographs were analysed independently to determine range of motion and assess device migration and/or subsidence.
Results: Of the 10 patients with cervical disc prosthesis scored for clinical success at one-year follow-up, 8 (80%) were classified as excellent, 1 (10%) was classified as fair and 1 (10%) was classified as poor. Of the 10 patients with cage fusion scored for clinical success at one-year follow-up, 8 (80%) were classified as excellent, 1 (10%) was classified as fair and 1 (10%) was classified as poor. Of the 10 patients with pallacos "fusion" scored for clinical success at one-year follow-up, 7 (70%) were classified as excellent, 2 (10%) was classified as fair and 1 (10%) was classified as poor. The range of motion for patient with cervical disk prosthesis at six months was unvaried compared to pre-op range of motion. The patients with anterior fusion lose the pre-op range of motion. There have been no device migrations or device subsidences in all patients.
Conclusion: The concept that interbody fusion of the cervical spine leads to accelerated degeneration of adjacent disc levels due to increased stress from the fusion is widely postulated. Therefore, reconstruction of a failed interverterbral disc with a functional disc prosthesis should offer the same benefits as decompression and fusion while simultaneously providing motion thereby protecting the adjacent level disc from the abnormal stresses associated with fusion by maintaining physiological motion and kinematics.