The efficacy of routine use of recombinant human bone morphogenetic protein–2 in occipitocervical and atlantoaxial fusions of the pediatric spine: a minimum of 12 months' follow-up with computed tomography

Abstract

<jats:sec> <jats:title>OBJECT</jats:title> <jats:p>The purpose of this study focusing on fusion rate was to determine the efficacy of recombinant human bone morphogenetic protein–2 (rhBMP-2) use in posterior instrumented fusions of the craniocervical junction in the pediatric population. The authors previously reported the short-term (mean follow-up 11 months) safety and efficacy of rhBMP-2 use in the pediatric age group. The present study reports on their long-term results (minimum of 12 months' follow-up) and focuses on efficacy.</jats:p></jats:sec> <jats:sec> <jats:title>METHODS</jats:title> <jats:p>The authors performed a retrospective review of 83 consecutive pediatric patients who had undergone posterior occipitocervical or atlantoaxial spine fusion at Texas Children's Hospital or Riley Children's Hospital during the period from October 2007 to October 2012. Forty-nine patients were excluded from further analysis because of death, loss to follow-up, or lack of CT evaluation of fusion at 12 or more months after surgery. Fusion was determined by postoperative CT scan at a minimum of 12 months after surgery. The fusion was graded and classified by a board-certified fellowship-trained pediatric neuroradiologist. Other factors, such as patient age, diagnosis, number of vertebral levels fused, use of allograft or autograft, dosage of bone morphogenetic protein (BMP), and use of postoperative orthosis, were recorded.</jats:p></jats:sec> <jats:sec> <jats:title>RESULTS</jats:title> <jats:p>Thirty-four patients had a CT scan at least 12 months after surgery. The average age of the patients at surgery was 8 years, 1 month (range 10 months–17 years). The mean follow-up was 27.7 months (range 12–81 months). There were 37 fusion procedures in 34 patients. Solid fusion (CT Grade 4 or 4−) was achieved in 89.2% of attempts (33 of 37), while incomplete fusion or failure of fusion was seen in 10.8%. Based on logistic regression analysis, there was no significant association between solid fusion and age, sex, BMP dose, type of graft material, use of postoperative orthosis, or number of levels fused. Three of 34 patients (8.8%) required revision surgery.</jats:p></jats:sec> <jats:sec> <jats:title>CONCLUSIONS</jats:title> <jats:p>Despite the large number of adult studies reporting positive effects of BMP on bone fusion, our long-term outcomes using rhBMP-2 in the pediatric population suggest that rates of fusion failure are higher than observed in contemporary adult and pediatric reports of occipitocervical and atlantoaxial spine fusions.</jats:p></jats:sec>

Spinal instrumentation in infants, children, and adolescents: a review

“…The safety and efficacy of BMP has been documented in adult and pediatric case reports and case series. 64, [130][131][132] Reported complications of BMP include seroma formation, softtissue swelling, delayed wound healing, and heterotopic bone formation. The long-term effects of BMP, such as oncogenesis, are unknown.…”

Comparison of Fusion Rates Based on Graft Material Following Occipitocervical and Atlantoaxial Arthrodesis in Adults and Children

“…Normative data to establish the degree of allowable motion over a fused segment for definitive determination of fusion is lacking. 28 A study by Sayama et al 7 includes 34 pediatric cases of occipitocervical or atlantoaxial fusion augmented with rhBMP-2. Fusion was determined by postoperative CT > 12 mo after surgery as interpreted by a neuroradiologist.…”

“…Despite reported high rates of fusion, our results, combined with those of Sayama and Sivakumar suggest that, in a generalized population, the rate may be lower than expected. 7,8 Sayama et al 7 reported a fusion rate of 89.2% for pediatric patients (10-17 yr) undergoing occipitocervical or atlantoaxial fusion with rhBMP-2 with >12 mo follow-up using CT imaging. Mazur et al 29 reported a 15.7% failure rate requiring revision surgery in 107 patients (1.2-17.9 yr) undergoing occipitocervical fusion.…”

Spinal column shortening for tethered cord syndrome associated with myelomeningocele, lumbosacral lipoma, and lipomyelomeningocele in children and young adults

“…However, we do cover this topic in a series of previously published studies. 10,21,31,32 Furthermore, written informed consent was obtained from the patient or legal guardian for off-label use of bone morphogenetic protein as described above.…”