Vertebral bone resorption after transforaminal lumbar interbody fusion with bone morphogenetic protein (rhBMP-2).
OBJECTIVE
Bone morphogenetic protein (rhBMP-2) has demonstrated an increased rate of interbody fusion when placed in the intervertebral space. Owing to this advantage, rhBMP-2 is being implanted with increasing frequency in the lumbar spine. The purpose was to quantify and describe the presence of bone resorption within the vertebral body after transforaminal lumbar interbody fusion with placement of rhBMP-2 within the disc space.


METHODS
Twenty-six patients were selected from a clinical database. Patients included in the study had undergone a transforaminal lumbar interbody fusion with BMP. Interbody implants included allograft dowels or interbody cages augmented with autograft or allograft bone. A computed tomography study of the lumbar spine a minimum of 3-month postoperatively was another inclusion criterion. Osteolytic defects were grouped into 3 categories on the basis of the size and extent of involvement in the vertebral body.


RESULTS
A total of 32 lumbar levels were reviewed. Fourteen males and 12 females with an average age of 46.0 years were included in the study. Bone resorption defects were noted in 22 of the 32 levels reviewed (69%). The defects were characterized as mild in 50% (11 of 22), moderate in 18% (4 of 22), and severe in 31% (7 of 22).


CONCLUSIONS
The benefit of rhBMP-2 to promote interbody fusion in the lumbar spine has been well documented. BMP has demonstrated an increased fusion rate and the ability to produce a robust fusion mass. rh-BMP-2's osseous remodeling potential may lead to bone resorption within the vertebral body.
McClellan
John W
JW
Nebraska Spine Center, Omaha, NE 68154-4438, USA. kjmccle@cox.net
Mulconrey
Daniel S
DS
Forbes
Robert J
RJ
Fullmer
Nancy
N
D000293:Adolescent; D000328:Adult; D000368:Aged; D055396:Bone Morphogenetic Protein 2; D019485:Bone Morphogenetic Proteins / Q000008:administration & dosage / Q000009:adverse effects*; D001862:Bone Resorption / Q000139:chemically induced* / Q000000981:diagnostic imaging; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007403:Intervertebral Disc; D008159:Lumbar Vertebrae; D008297:Male; D008875:Middle Aged; D011859:Radiography; D011994:Recombinant Proteins / Q000008:administration & dosage / Q000009:adverse effects*; D012189:Retrospective Studies; D012720:Severity of Illness Index; D013122:Spinal Diseases / Q000601:surgery*; D013123:Spinal Fusion / Q000379:methods*; D016212:Transforming Growth Factor beta / Q000008:administration & dosage / Q000009:adverse effects*
D055396:Bone Morphogenetic Protein 2; D019485:Bone Morphogenetic Proteins; D011994:Recombinant Proteins; D016212:Transforming Growth Factor beta; C499469:recombinant human bone morphogenetic protein-2