Neurologic impairment from ectopic bone in the lumbar canal: a potential complication of off-label PLIF/TLIF use of bone morphogenetic protein-2 (BMP-2).
BACKGROUND
Bone morphogenetic protein-2 (BMP-2) (Infuse) has been approved for use in anterior lumbar fusion in conjunction with an LT cage. However, off-label use is seen with anterior cervical fusion, posterior lumbar interbody fusion (PLIF), and transforaminal lumbar interbody fusion (TLIF). The Federal Food and Drug Administration trial of BMP-2 in a PLIF application was halted because of a high incidence of ectopic bone forming in the neural canal (75%). The authors did not find a correlation between ectopic bone and increased leg pain. They concluded that the ectopic bone was a radiographic phenomenon and not associated with clinical findings. Complications using BMP in the cervical spine have been reported. Heretofore, there has not been a similar warning voiced for use of BMP in a lumbar PLIF or TLIF.


OBJECTIVE
The purpose was to report five cases of ectopic bone in the canal associated with PLIF/TLIF off-label use of BMP-2 potentially contributing to abnormal neurologic findings.


METHODS
This is an observational cohort study of patients referred to a tertiary care private medical center.


METHODS
This was a retrospective chart review of patients referred to a tertiary spine institute with complications after surgery where BMP-2 had been used in an off-label PLIF or TLIF application. Patient demographics, operating room (OR) notes from the index BMP surgery, imaging studies, and current clinical status were reviewed.


RESULTS
Five cases of ectopic bone in the spinal canal with potential neurologic compromise were identified.


CONCLUSIONS
It does appear that ectopic bone in the spinal canal associated with BMP-2 use in PLIF or TLIF may contribute to symptomatic neurologic findings in rare cases. Revision surgeries are difficult. This article challenges a previous publication, which concluded that the high incidence of ectopic bone was of no clinical significance. Isolating BMP anteriorly in the disc space using layered barriers of bone graft between the BMP and the annular defect may reduce the incidence of ectopic bone in the spinal canal. Surgeons need to weigh the benefits versus risks of any technology used off label when making treatment decisions with their patients.
Wong
David A
DA
Advanced Center for Spinal Microsurgery, Presbyterian St. Luke's Medical Center, Denver, CO, USA. ddaw@denverspine.com
Kumar
Anant
A
Jatana
Sanjay
S
Ghiselli
Gary
G
Wong
Katherine
K
D000328:Adult; D055396:Bone Morphogenetic Protein 2 / Q000009:adverse effects*; D003131:Combined Modality Therapy; D005260:Female; D006801:Humans; D008159:Lumbar Vertebrae / Q000293:injuries* / Q000473:pathology / Q000601:surgery*; D008279:Magnetic Resonance Imaging; D008297:Male; D011183:Postoperative Complications / Q000139:chemically induced* / Q000473:pathology / Q000601:surgery; D012086:Reoperation; D012189:Retrospective Studies; D013117:Spinal Cord Compression / Q000139:chemically induced / Q000473:pathology / Q000601:surgery; D013123:Spinal Fusion
C525718:BMP2 protein, human; D055396:Bone Morphogenetic Protein 2