Bone morphogenetic protein 7 and autologous bone graft in revision surgery for non-union after lumbar interbody fusion.
BACKGROUND
Potential adverse and unknown long-term effects as well as additional costs limit the use of BMPs (Bone morphogenetic proteins) in primary fusion procedures. However, the proven osteoinductive properties render BMPs attractive for the attempt to reach fusion of symptomatic non-unions. The aim of this study is to evaluate the fusion rate and potential disadvantages of eptotermin alfa (rhBMP-7) used with autologous bone graft in revision procedures for lumbar pseudoarthrosis.


METHODS
At our institution, rhBMP-7 has been used to improve fusion rates in revision surgery for symptomatic pseudoarthrosis during the past 10 years. Eighty-four fusion procedures using rhBMP-7 between 08/2003 and 07/2011 were revisions due to symptomatic lumbar pseudoarthrosis. The surgical approach was posterior in three and combined anterior-posterior in 71 patients. Of those, 74 patients had either reached fusion or had follow-up of at least 39.5 months (range 21-80 months) in the case of pseudoarthrosis. These 74 patients have been included in a retrospective follow-up study.


RESULTS
In 60 patients (81.1 %) the rhBMP-7 procedure was successful. In 14 patients, pseudoarthrosis persisted or fusion was questionable. Of those patients 12 accounted for persisting L5-S1 non-union. Persisting non-unions were found in 26.7 % of the study after four or more segment instrumentations compared to the 16.9 % after mono-, bi-, or three-segment instrumentation, and in four of 14 patients with spondylodesis of three or more levels above a pseudoarthrotic lumbosacral junction. Adverse effects related to the use of eptotermin alfa were rare in this group with symptomatic ectopic bone formation in one patient.


CONCLUSIONS
Using rhBMP-7 with autologous bone graft in revisions for lumbar pseudoarthrosis via an anterior approach is safe and can lead to fusion even under unfavorable biomechanical conditions. However, successful outcome depends on the individual constellation. Treatment of non-unions of the lumbosacral junction remains especially difficult in cases with solid fusions above those pseudoarthrotic levels.


METHODS
4; retrospective follow-up study.
Department for Spinal Surgery and Paraplegiology, Zentralklinik Bad Berka, Robert-Koch-Allee 9, 99438, Bad Berka, Germany. s.werle@asklepios.com.|Department for Spinal Surgery, Asklepios Clinic Lindau, Friedrichshafener Strasse 82, 88131, Lindau, Germany. s.werle@asklepios.com.
Stephan
S
Werle
Department for Spinal Surgery and Paraplegiology, Zentralklinik Bad Berka, Robert-Koch-Allee 9, 99438, Bad Berka, Germany.
Kais
K
AbuNahleh
Department for Spinal Surgery and Paraplegiology, Zentralklinik Bad Berka, Robert-Koch-Allee 9, 99438, Bad Berka, Germany.
Heinrich
H
Boehm
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D055419:Bone Morphogenetic Protein 7 / Q000627:therapeutic use*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007085:Ilium / Q000637:transplantation*; D008159:Lumbar Vertebrae / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D012086:Reoperation; D012189:Retrospective Studies; D013123:Spinal Fusion; D014182:Transplantation, Autologous
C525819:BMP7 protein, human; D055419:Bone Morphogenetic Protein 7
BMP7; Bone morphogenetic protein; Eptotermin alfa; Lumbar non-union; Osteogenic protein 1; Revision surgery