Abstract
Objective: To determine if a porous, coralline-derived hydroxyapatite block (ProOsteon 500TM, Interpore, Irvine, CA) is a suitable substitute for tricortical iliac crest autograft in cervical interbody fusion.
Design: A prospective randomised trial with two-year follow-up comparing clinical and radiographic outcomes in patients receiving either iliac crest or hydroxyapatite grafts in cervical interbody fusion.
Subjects: Twenty-nine patients undergoing cervical fusion and anterior plating were randomised to receive either iliac crest (Group I) or hydroxyapatite (Group II) interbody grafts. Fourteen patients (19 grafts) in Group I and twelve patients (18 grafts) in Group II were available for final analysis. Both groups were similar with respect to age, sex, diagnosis and levels fused.
Outcome Measures: The SF-36 and Oswestry Disability Index were used to measure clinical outcome. Post-op and final follow-up radiographs were analysed for graft fragmentation, loss of height, loss of angular alignment and hardware failure to assess structural integrity of the graft. Computed or plain tomography was used to evaluate fusion.
Results: Groups I and II demonstrated improvement in preoperative scores for bodily pain (p=. 016 and. 016 respectively) and physical functioning (p=. 050 and. 016 respectively) at final follow-up. There was no significant difference in SF-36 and Oswestry scores between the two groups. Successful radiographic fusion was similar in both groups (79% in Group I and 76% in Group II). Graft fragmentation occurred in 89% of the hydroxyapatite grafts and 11% of the autografts (p=. 001). Greater than 2mm of graft height and 3° of segmental lordosis were lost in 55% of hydroxyapatite grafts vs. 11% of autografts (p=. 009). One patient in Group II and none in Group I required revision surgery for graft failure. The high rate of early radiographic failure in the hydroxyapatite grafts prompted suspension of further enrolment in the clinical trial.
Conclusions: ProOsteon 500 coralline hydroxyapatite blocks do not possess adequate structural integrity to resist axial loading and maintain disc height or segmental lordosis during cervical interbody fusion.
Abstracts prepared by Mr. A. J. Stirling, FRCS, and Miss A. Weaver. Correspondence should be addressed to Miss A. Weaver at the Research and Teaching Centre, Royal Orthopaedic Hospital, Northfield, Birmingham, B31 2AP, UK
BritSpine 2002, the second combined meeting of the British Association of Spinal Surgeons, the British Cervical Spine Society, The British Scoliosis Society and the Society for Back Pain Research, took place at the International Convention Centre in Birmingham UK between 27th February and 1st March 2002. The following presentations and posters were given and displayed.
References:
1 Bohlman HH, Emery MA, Goodfellow DB. Robinson anterior cervical discectomy and arthrodesis for cervical radiculopathy. J Bone Joint Surg (Am)1993; 75: 1298–1307. Google Scholar
2 Wigfield CC, Nelson RJ. Nonautologous interbody fusion materials in cervical spine surgery. Spine2001; 26: 687–694 Google Scholar
