Anterior cervical discectomy and fusion with implantable titanium cage: initial impressions, patient outcomes and comparison to fusion with allograft.
BACKGROUND
The use of metal cage prosthetic devices in anterior cervical discectomy with fusion (ACDF) has increased rapidly. One of these devices is the titanium Rabea cage (Signus, Alzenau, Germany) [correction]. There are no peer-reviewed objective reports on the use of these cages in cervical discectomy.


OBJECTIVE
The authors present preliminary outcomes data on the Rabea cage. This study is intended to provide adjunct data for surgeons who are using or are considering the use of these devices.


METHODS
Patients in a private practice were studied prospectively as part of a long-term assessment of outcomes using several surgical procedures. Data were collated and analyzed by an independent researcher.


METHODS
Rabea cages were used in consecutive candidates (n=37) for ACDF. The results using Rabea cages were compared with two prospectively studied control groups, one historical (n=66) and one concurrent (n=28), both groups using ACDF with bone allograft and no instrumentation.


METHODS
Success at 6 months after surgery was determined using six major patient-reported outcome measures, including visual analog scales (VAS) for arm and neck pain, the Oswestry pain and disability scale, four-part (excellent-through-poor) scales for measurement of return to activities of daily living or to work and satisfaction with the results of surgery. Perioperative complications, number of vertebral levels fused, and worker's compensation and smoking status were also compared among the study groups. Fusion and subsidence were evaluated for the Rabea cage group.


METHODS
Criteria for inclusion consisted of consecutive patients who presented with unremitting radicular arm pain, with or without neck pain, and/or a neurological deficit that correlated with appropriate level and side neural compression on magnetic resonance imaging or computed tomography. Questionnaire follow-up was at 6 months after surgery with 100% compliance.


RESULTS
A total of 50 cages were implanted in the 37 patients. At 6-month follow-up, 78% of patients reported successful arm pain relief (VAS scores below 5). Patient satisfaction was successful in 78% of the cases. Other success rates included neck pain relief in 73% and Oswestry pain and disability scale in 70%. There was a median improvement in the Oswestry scores of 28 points (61% change). Worker's compensation patients fared dramatically worse than did the noncompensation patients in all outcome measurements. Combining all three study groups resulted in significantly worse outcomes for multilevel than for single-level procedures and for smokers compared with nonsmokers, but low case numbers precluded conclusive analysis for the Rabea group alone. In the Rabea group there were two complications, neither cage related, whereas none were reported for the ACDF controls. Rabea group fusion rates were 84% at 3 months and 95% at 6 months, but the clinical relevance of this radiological evidence when metal prostheses are used is questionable. The outcomes results were clinically and statistically indistinguishable from those of our control groups and were similar to published studies using other titanium cages.


CONCLUSIONS
This is the first prospective, independently conducted report on Rabea cages. Results of the short-term (6 months) follow-up did not differ from outcomes results in our patients who have undergone ACDF with bone allograft. Although this is a preliminary assessment, the Rabea cage may represent an alternative to bone dowels and hip graft. As is the case for other allografts, artificial or bone, the main advantage is elimination of donor site complications, and the disadvantages include difficulty in radiographic assessment of fusion and potential for cage subsidence.
Moreland
Douglas B
DB
Buffalo Neurosurgery Group, 550 Orchard Park Road, Buffalo, NY 14224, USA. bng@buffnet.net
Asch
Harold L
HL
Clabeaux
David E
DE
Castiglia
Gregory J
GJ
Czajka
Gregory A
GA
Lewis
P Jeffrey
PJ
Egnatchik
James G
JG
Cappuccino
Andrew
A
Huynh
Lien
L
D000203:Activities of Daily Living; D000328:Adult; D000368:Aged; D016025:Bone Transplantation; D016022:Case-Control Studies; D002574:Cervical Vertebrae / Q000000981:diagnostic imaging / Q000601:surgery*; D003131:Combined Modality Therapy; D017586:Diskectomy / Q000379:methods*; D005260:Female; D006801:Humans; D007405:Intervertebral Disc Displacement / Q000000981:diagnostic imaging / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D010147:Pain Measurement; D017060:Patient Satisfaction; D011183:Postoperative Complications; D011336:Probability; D011446:Prospective Studies; D019736:Prostheses and Implants; D011859:Radiography; D016059:Range of Motion, Articular / Q000502:physiology; D020127:Recovery of Function; D018570:Risk Assessment; D012720:Severity of Illness Index; D013123:Spinal Fusion / Q000379:methods*; D014025:Titanium; D014184:Transplantation, Homologous; D016896:Treatment Outcome
D014025:Titanium