Comparison between Carbon Fiber Composite Frame and PEEK(Polyetheretherketone) Cages in the Efficiency of Interbody Fusion for Surgical Treatment of Cervical Disc Diseases

Jung, Yong Tae; Paeng, Sung Hwa; Pyo, Se Young; Kim, Moo Sung; Jeong, Young Gyun

Abstract

OBJECTIVE
To evaluate the efficiency of carbon fiber composite frame and polyetheretherketone(PEEK) cages in the interbody fusion for surgical treatment of cervical disc diseases, we analyzed fusion time and subsidence rate.
METHODS
From March 2004 to February 2007 fifty patients with cervical disc diseases underwent anterior discectomy and interbody fusion in 60 levels. The subjects were 26 men and 24 women with a mean age of 57.2 years ranging from 29 to 67. Among them 25 patients underwent operations using carbon fiber composite frame cages (Osta-Pek(R), Co-Ligne, Zurich, Switzerland) in 30 levels, and 25 patients using PEEK cages(Cornerstone(R), Medtronic, TN, USA) in 30 levels. The cages were packed with allograft bone or bone substitute(demineralised bone matrix). On lateral flexion-extension radiographs anterior disc height and posterior disc height were measured at preoperative time, postoperative 1, 3, 6 and 12 month respectively. Segmental stability(lordotic angle) was measured at postoperative 3, 6, and 12 months in all 60 levels for fusion time.
RESULTS
The anterior disc height and posterior disc height were 4.87+/-1.36mm and 3.25+/-0.73mm at preoperative time, 7.32+/-1.41mm and 4.77+/-0.80mm at postoperative 1month, and 5.87+/-1.47mm and 3.22+/-0.93mm at posto- perative 12 months respectively in carbon fiber composite frame cage group(30 levels). The anterior disc height and posterior disc height were 4.88+/-1.18mm and 3.75+/-0.75mm at preoperative time, 7.26+/-1.17mm and 5.27+/-0.55mm at postoperative 1month, and 6.23+/-1.16mm and 3.96+/-0.69mm at postoperative 12months respectively in PEEK cage group(30 levels). The angular motion at the fused segment was measured in carbon fiber composite frame cage and PEEK group for segmental stability(two degrees or less flexion-extension range of motion at the fusion site). The carbon fiber composite frame cage group was stabilized between postoperative 3 months and 6 months, but PEEK cage group was stabilized between 6 months and 9 months. This result was statistically significant(p-value =0.003)(Fig. 2). Fusion rate of carbon composite frame cage group was 28%, 67% and 83% at 3, 6, 12 months after operation, and that of PEEK cage group was 24%, 48% and 86% at postoperative 3, 6 and 12 months respe- ctively. Complications included transient hoarseness, cage migration and subsidence. There was no persistent hoar- seness or Horner syndrome. We have observed severe subsidence(above 3mm) in two cases(6.7%) of carbon fiber composite frame cage group only. Anterior cage migration was shown in each one case(3.3%) of carbon fiber composite frame and PEEK cage group.
CONCLUSION
The carbon fiber composite frame cage group showed a tendency of earlier fusion than PEEK cage group but both cages were same in the fusion rate at postoperative 1 year. But, restoration or maintenance of inter- vertebral height was much better in PEEK cage group than carbon fiber composite frame cage group. Subsidence rate was higher in carbon fiber cage group rather than PEEK cage group.