Transforaminal Lumbar Interbody Fusion with rhBMP-2 followed 4 years: A large series with diagnosis-based outcomes and complications

2010

SUMMARY

This is the largest series of TLIF with PEEK cage and interbody rhBMP-2 in the literature, 282 consecutive adults followed 48 months (24-76 months). Arthrodesis was noted in 98% across a variety of spinal disorders (degenerative disease-124, spondylolisthesis-92, scoliosis-62, kyphosis-4). Most complications occurred with deformity patients. Five BMP-related complications occurred, 2 seromas and 3 with bony overgrowth, all resolving with surgical decompression. Off-label BMP used with TLIF appears highly effective for a variety of spinal disorders.

INTRODUCTION

TLIF provides improved fusion rates and anterior column support. Off-label use of rhBMP-2 with TLIF is common. Reliable fusion rates and complications have been reported(largest series: 86 patients followed 27 mo). This is the largest report of TLIF with BMP, with analysis of complications and outcomes across the spectrum of spinal disorders.

METHODS

Prospective outcomes were reviewed on 282 consecutive adults undergoing open posterior instrumented fusion (PSF) with TLIF, PEEK cage, rhBMP-2 average 8.4mg/disc (4-12mg/disc) at 485 discs, and followed 48 months (24-76 mo). Dx: degenerative-124, spondy-92, scoliosis-62, kyphosis-4. Age avg 60years (19-88yrs), 23 smokers, 109 had prior decompression/fusion. PSF avg 3.4 levels (1-16 levels); TLIF avg 1.7 levels (1-4 levels), 1 level-126, 2 levels-112, 3 levels-41, 4 levels-3. Outcomes included VAS pain scores, Oswestry Disability Index (ODI), pain medication records, and radiographic imaging pre-op, 1 year, 2 years, and latest follow-up. Fusion was defined as bridging interspace bone, no loosening of instrumentation, no motion on flex-ext radiographs.

RESULTS

Nonunions: 6 patients (6/485 discs; 4 scoliosis, 1 spondy, 1 degen), 4/6 at L5-S1. Nonunion BMP dose: 8mg-4, 6mg-1, 4mg-1. Revision surgery for BMP-related problems: seroma-2, bony overgrowth into foramina-3, all resolved. Other complications: adjacent degeneration-106 (17 revised), adjacent fracture-17 (9 scoliosis, 7 revised), infection-4, late instrumentation removal-7. Osteolysis and cage subsidence were not seen. Significant improvement was noted in VAS (pre-op-6.3, 1 yr-2.9, 2 yr-3.0, P<.001) and ODI (pre-48, 1yr-25, 2yr-28, P<.001), and pain medication requirements.

CONCLUSIONS

Instrumented PSF with TLIF, PEEK cage, and rhBMP-2 produces reliable fusion(98%) and improved outcomes in adults requiring arthrodesis. Most complications occurred in deformity patients; BMP related complications were uncommon, none at 4mg/disc dose.

SIGNIFICANCE

Off-label use of interbody BMP with TLIF, PEEK cages and PSF with instrumentation achieves reliable clinical and radiographic outcomes.