Pseudarthrosis in multilevel anterior cervical fusion with rhBMP-2 and allograft: analysis of one hundred twenty-seven cases with minimum two-year follow-up.

Abstract

STUDY DESIGN:

Consecutive case series.

OBJECTIVE:

The purpose of this study was to analyze the pseudarthrosis rate in a large series of recombinant human bone morphogenetic protein-2 (rhBMP-2) augmented multilevel (> or =3 levels) anterior cervical fusions.

SUMMARY OF BACKGROUND DATA:

The reported pseudarthrosis rate following anterior cervical fusion varies from 0% to 20% for single-level and up to 50% for multilevel fusions. It has been postulated that the use of rhBMP-2 may decrease the pseudarthrosis rate.

METHODS:

A consecutive series of patients with cervical spondylosis and/or disc herniation who underwent anterior cervical fusion with rhBMP-2, structural allograft, and plate fixation with a minimum 2-year follow-up were analyzed by experienced, independent spine surgeons.

RESULTS:

A total of 127 patients (54 men and 73 women with mean age of 54 +/- 10 years [range, 32-79]) were examined. Seventy-five (59.1%) patients underwent a 3-level fusion, 34 (26.7%) underwent a 4-level fusion, and 18 (14.2%) underwent a 5-level fusion. Of the 451 fusion segments, 14 segments (3.1%) in 13 of 127 patients (10.2%) had evidence of pseudarthrosis at 6 months following surgery. Of the 13 patients with a pseudarthrosis, 3 had a 3-level fusion (3/75 patients [4.0%]), 6 had a 4-level fusion (6/34 patients [17.4%]), and 4 had a 5-level fusion (4/18 patients [22.2%]). Five patients were asymptomatic and were not revised, but the remaining 8 patients required additional surgery. In 12 of 13 patients with a pseudarthrosis, the nonunion occurred at the lowest fusion level and at the cervicothoracic junction. The only statistically significant risk factor for developing a pseudarthrosis was the number of fusion levels.

CONCLUSION:

In a large series of rhBMP-2 augmented multilevel fusions, the pseudarthrosis rate was 10.2% at 6 months following surgery. Since the risk of pseudarthrosis increases with the number of fusion levels, a long fusion lever arm may biomechanically overwhelm the biologic advantage of rhBMP-2. While rhBMP-2 is known to enhance fusion rates, it does not guarantee fusion in all situations.

• Authors: Hong Xing Shen, Jacob M Buchowski, Jin S Yeom, Gabriel Liu, Nan Lin, K Daniel Riew
• Journal: Spine (Spine (Phila Pa 1976)) Vol. 35 Issue 7 Pg. 747-53 (Apr 01 2010) ISSN: 1528-1159 [Electronic] United States
• PMID: 20228711 (Publication Type: Journal Article)

Chemical References

• Bone Morphogenetic Protein 2
• Recombinant Proteins

Topics

• Adult
• Aged
• Bone Morphogenetic Protein 2 (therapeutic use)
• Bone Plates (adverse effects)
• Bone Transplantation (adverse effects, methods)
• Cervical Vertebrae (surgery)
• Female
• Humans
• Intervertebral Disc Displacement (surgery)
• Male
• Middle Aged
• Odds Ratio
• Pseudarthrosis (etiology)
• Recombinant Proteins (therapeutic use)
• Risk Factors
• Spinal Fusion (adverse effects, methods)
• Spondylosis (surgery)
• Treatment Outcome