A pilot study evaluating the safety and efficacy of OP-1 Putty (rhBMP-7) as a replacement for iliac crest autograft in posterolateral lumbar arthrodesis for degenerative spondylolisthesis.
METHODS
A prospective, randomized, controlled, multicenter clinical study was conducted.


OBJECTIVE
To compare the clinical and radiographic outcomes of patients treated with OP-1 (BMP-7) Putty to autogenous iliac crest bone graft for one-level uninstrumented posterolateral fusion of the lumbar spine following decompressive laminectomy for the treatment of symptomatic degenerative spondylolisthesis with spinal stenosis.


BACKGROUND
Preclinical studies have demonstrated that osteoinductive recombinant human osteogenic protein 1 in the form of OP-1 Putty is successful at achieving a posterolateral fusion in rabbits and dogs without any significant safety concerns.


METHODS
Thirty-six patients with degenerative lumbar spondylolisthesis and symptoms of neurogenic claudication were randomized (2:1) to either OP-1 Putty (3.5 mg of OP-1 per side) or autogenous iliac crest bone graft for one-level uninstrumented posterolateral fusion following a decompressive laminectomy. Enrollment in the study was complete when 24 OP-1 Putty patients and 12 autograft patients had been randomized and treated. A patient administered Oswestry scale and SF-36 scale were used to determine clinical outcomes. Independent, blinded neuroradiologists reviewed both static and dynamic radiographs to determine fusion status.


RESULTS
At the 1-year follow-up, 32 patients were available for clinical analysis and 29 patients were available for radiographic review. Clinical success as measured on the Oswestry scale was achieved by 18 of 21 (86%) OP-1 Putty patients and 8 of 11 (73%) autograft patients. SF-36 pain index scores showed similar results. Fourteen of 19 (74%) OP-1 Putty patients and 6 of 10 (60%) autograft patients achieved a successful posterolateral fusion fulfilling all fusion criteria. Of the 29 evaluable patients, 15 were both clinical and radiographic successes, 5 were radiographic successes but were clinical failures, 1 patient was both a radiographic and clinical failure, and 8 patients were radiographic failures but were clinical successes. No systemic toxicity, ectopic bone formation, recurrent stenosis, or other adverse events related to the OP-1 Putty implant were observed.


CONCLUSIONS
Although the posterolateral spine is a challenging fusion environment in patients with degenerative spondylolisthesis, successful radiographic fusion was obtained using OP-1 Putty at a rate that was similar to autograft given the number of patients in this study. Importantly, there were no apparent adverse consequences related to the use of the OP-1 Putty implant in this patient population.
Vaccaro
Alexander R
AR
Department of Orthopaedic Surgery, Thomas Jefferson University, Rothman Institute, Philadelphia, PA 19107, USA. alexvaccaro3@aol.com
Patel
Tushar
T
Fischgrund
Jeffrey
J
Anderson
D Greg
DG
Truumees
Eeric
E
Herkowitz
Harry N
HN
Phillips
Frank
F
Hilibrand
Alan
A
Albert
Todd J
TJ
Wetzel
Todd
T
McCulloch
John A
JA
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001672:Biocompatible Materials; D055419:Bone Morphogenetic Protein 7; D019485:Bone Morphogenetic Proteins / Q000008:administration & dosage / Q000627:therapeutic use*; D018786:Bone Substitutes / Q000008:administration & dosage / Q000627:therapeutic use*; D016025:Bone Transplantation; D002266:Carboxymethylcellulose Sodium / Q000008:administration & dosage / Q000627:therapeutic use; D024042:Collagen Type I / Q000008:administration & dosage / Q000627:therapeutic use; D019299:Decompression, Surgical; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007796:Laminectomy; D008159:Lumbar Vertebrae / Q000601:surgery*; D008297:Male; D008422:Materials Testing; D008875:Middle Aged; D010865:Pilot Projects; D011446:Prospective Studies; D011859:Radiography; D011994:Recombinant Proteins / Q000008:administration & dosage / Q000627:therapeutic use; D016037:Single-Blind Method; D013123:Spinal Fusion / Q000379:methods*; D013130:Spinal Stenosis / Q000000981:diagnostic imaging / Q000209:etiology / Q000601:surgery*; D013168:Spondylolisthesis / Q000150:complications / Q000000981:diagnostic imaging / Q000601:surgery*; D014182:Transplantation, Autologous; D016896:Treatment Outcome
C525819:BMP7 protein, human; D001672:Biocompatible Materials; D055419:Bone Morphogenetic Protein 7; D019485:Bone Morphogenetic Proteins; D018786:Bone Substitutes; D024042:Collagen Type I; D011994:Recombinant Proteins; D002266:Carboxymethylcellulose Sodium