CERVICAL INTERBODY FUSION WITH A HYDROXY-APATITE CERAMIC (HAC)-TITANIUM CAGE–CLINICAL AND RADIOLOGICAL RESULTS IN 596 PATIENTS WITH SOFT AND HARD DISC PROLAPSES.

Abstract

Introduction: Many different techniques exist for cervical interbody fusion after discectomy for soft and hard disc prolapses. The six years clinical and radiological results and the complications with a hydroxy-apatite ceramic (hac)-titanium implant are presented.

Methods: Between 1/1995 and 12/2000 a titanium implant coated with hydroxy-apatite ceramic (hac) has been used for ventral cervical interbody fusion after discectomy in 596 patients with soft and hard disc prolapses who were operated in 670 levels. There were 333 male and 263 female patients. The mean age was 48.2 years. Clinical and radiological follow-up studies were performed direct after operation and 6 weeks, 6 months and 1 year later with an average follow-up of 14 months. The functional outcome was assessed according to Odom’s score, and the neurological outcome according to Kadoya’s score.

Results: 93.2 % of the patients had a good to excellent result according to Odom’s score at follow-up whereas the neurological findings showed improvement in 71.2 % and no change in 27.9 %. After 6 months a good bony fusion could be seen around 91.2 % of the implants, and after 12 months around 95.7 %. 1,7 % of the operated patients developed a recurrent laryngeal nerve injury. Three implants broke into the adjacent vertebral endplate. Six patients had a second operation because of a dislocated cage. An adjacent segment pathology occured in 25 patients (4.2 %), of whom 15 patients had a second operation.

Conclusions: With the use of this hydroxy-apatite ceramic (hac)-titanium implant we get an immediate postoperative stability of the cervical spine without the need of any orthosis. Harvesting of bone grafts is unnecessary which reduces operation time and eliminates donor site complications. The clinical and radiological are good and comparable to other fusion techniques in the cervical spine and the complication rate is low. If the number of adjacent segment pathology can be reduced with total disc arthroplasty has to be clarified in further comparable studies.