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Incidence and Outcome of Graft Resorption in Anterior Lumbar Interbody Fusion: Using Femoral Ring Allografts and Recombinant Human Bone Morphogenetic Protein-2

Kayanja, Mark MD, PhD*; Orr, Robert Douglas MD, FRCS(C)

doi: 10.1097/BRS.0000000000000145
Clinical Case Series

Study Design. Retrospective cohort.

Objective. To determine the incidence of resorption after anterior lumbar interbody fusion (ALIF) and its effect on outcome.

Summary of Background Data. Recombinant human bone morphogenetic protein-2 (rhBMP-2) used in ALIF has been associated with a 0.5% to 82% incidence of resorption. This has been described as either a complication or part of the natural history. We postulate that early resorption (≤4 mo) in ALIF using femoral ring allograft augmented with rhBMP-2 supplemented with posterior instrumentation has no effect on outcome.

Methods. Institutional review board–approved retrospective 60 chart cohort study of ALIF using femoral ring allograft–augmented rhBMP-2 supplemented with posterior instrumentation from May 5, 2005, to April 6, 2010. Two groups were based upon the presence or absence of early graft resorption (≤4 mo). Patients were seen prior to surgery and postoperatively until 29 ± 20 months (last visit). Follow-up visual analogue scale pain scores and radiographical evidence of fusion were measured and compared between the 2 groups.

Results. Sixty patients, 27 females and 33 males had follow-up for 29 ± 20 months. Group 1 (33 patients, 45 levels) and group 2 (27 patients, 36 levels) were identical in age (P = 0.62), sex distribution (P = 0.43), preoperative pain score (P = 0.63), and in the rhBMP-2 dose per level (P = 0.77). There were no significant group differences in postoperative visual analogue scale scores but a trend to higher fusion rate in group 1 was seen (P = 0.07) at 6 months. There was a 40% incidence of early resorption with no significant differences in visual analogue scale scores or fusion rate between both groups.

Conclusion. There is a 40% incidence of early resorption (≤4 mo) that had no significant effect on pain score or fusion rate. Resorption should be considered part of the fusion process and not necessarily a complication.

Level of Evidence: 3

Retrospective 60 chart cohort with early (n = 33) versus no resorption (n = 27) groups identical in age (P = 0.62), sex distribution (P = 0.43), preoperative pain (P = 0.63), and recombinant human bone morphogenetic protein-2 dose (P = 0.77). There was 40% early resorption that had no significant effect on visual analogue scale score or fusion rate.

*Department of Orthopaedics, Cleveland Clinic, Cleveland, OH; and

Center for Spine Health, Lutheran Hospital, Cleveland, OH.

Address correspondence and reprint requests to Mark Kayanja, MD, PhD, CORE Institute, 18444 N 25th Avenue, Phoenix, AZ 85023; E-mail:

Acknowledgment date: March 4, 2013. Revision date: September 26, 2013. Acceptance date: November 18, 2013.

The device(s)/drug(s) that is/are the subject of this manuscript is/are not FDA-approved for this indication and is/are not commercially available in the United States.

No funds were received in support of this work.

Relevant financial activities outside the submitted work: consultancy, employment, patents, travel/accommodations/meeting expenses.

© 2014 by Lippincott Williams & Wilkins