Accelerating lumbar fusions by combining rhBMP-2 with allograft bone: a prospective analysis of interbody fusion rates and clinical outcomes.
BACKGROUND
Recombinant human bone morphogenetic protein-2 (rhBMP-2) is an osteoinductive protein approved for use in the anterior lumbar interspace. High fusion rates with rhBMP-2 have been reported with threaded interbody allograft dowels. There may be a clinical benefit for the patient by adding rhBMP-2 to the allograft.


OBJECTIVE
To compare the fusion rates and clinical outcomes of patients treated with allograft interbody fusions with and without the addition of rhBMP-2.


METHODS
Prospective consecutive patient enrollment with minimum 24-month follow-up.


METHODS
Seventy-five patients with lumbar interbody fusions at 1-3 spinal segments.


METHODS
Clinical: Numerical Rating Scale (NRS) and Oswestry Disability Index (ODI). Radiographic: X-ray and computed tomographic scan analysis using the Molinari-Bridwell fusion scale.


METHODS
Seventy-five patients scheduled for lumbar fusion were enrolled sequentially. Group 1: 30 patients had anterior interbody allografts alone. Group 2: 45 patients had anterior interbody allograft filled with rhBMP-2. All cases had posterior pedicle screw instrumentation. A total of 165 surgical levels (62 allograft alone/103 allograft+BMP) were included. Fusion data and clinical outcomes were collected for a minimum of 2 years after surgery.


RESULTS
Statistically higher fusion rates were observed in the patients with BMP at all time points compared with allograft alone. Group 2 (+ BMP) fusion rates were 94%, 100%, and 100% at 6, 12, and 24 months after surgery. Group 1 (-BMP) fusion rates were 66%, 84%, and 89% at the same time intervals. Clinical outcomes were significantly improved in Group 2 compared with Group 1 at 6 months. There were no revisions (0%) in the BMP group and 4 revision fusion surgeries (13%) in the allograft group. No untoward effects were attributable to the rhBMP-2.


CONCLUSIONS
Our study confirms the efficacy of an innovative lumbar fusion technique: an interbody femoral ring allograft, combined with an osteoinductive stimulant (rhBMP-2), protected by pedicle screws. This combination of a structural interbody allograft with rhBMP-2 eliminates the insult of iliac crest harvest, allows for reliable radiographic analysis, and results in successful fusion formation in 100% of the cases in this study.
Slosar
Paul J
PJ
Spine Care Medical Group, San Francisco Spine Institute, 1850 Sullivan Ave., #200, Daly City, CA 94015-2221, USA. pslosar@spinecare.com
Josey
Robert
R
Reynolds
James
J
D000328:Adult; D055396:Bone Morphogenetic Protein 2; D019485:Bone Morphogenetic Proteins / Q000627:therapeutic use*; D001863:Bone Screws; D016025:Bone Transplantation / Q000379:methods*; D005260:Female; D006801:Humans; D008159:Lumbar Vertebrae / Q000601:surgery; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D011994:Recombinant Proteins / Q000627:therapeutic use; D013123:Spinal Fusion / Q000379:methods*; D016212:Transforming Growth Factor beta / Q000627:therapeutic use*; D014184:Transplantation, Homologous; D016896:Treatment Outcome
C525718:BMP2 protein, human; D055396:Bone Morphogenetic Protein 2; D019485:Bone Morphogenetic Proteins; D011994:Recombinant Proteins; D016212:Transforming Growth Factor beta