Use of rhBMP-2 for adult spinal deformity surgery: patterns of usage and changes over the past decade

Developing a risk score to inform the use of rhBMP-2 in adult spinal deformity surgery

BACKGROUND

Recombinant human bone morphogenetic protein-2 (rhBMP-2) has not shown superior benefit overall in cost-effectiveness during adult spinal deformity (ASD) surgery.

STUDY DESIGN/SETTING

Retrospective PURPOSE: Generate a risk score for pseudarthrosis to inform the utilization of rhBMP-2, balancing costs against quality of life and complications.

METHODS

ASD patients with 3-year data were included. Quality of life gained was calculated from ODI to SF-6D and translated to quality-adjusted life years (QALYs). Cost was calculated using the PearlDiver database and CMS definitions for complications and comorbidities. Established weights were generated for predictive variables via logistic regression to yield a predictive risk score for pseudarthrosis that accounted for frailty, diabetes, depression, ASA grade, thoracolumbar kyphosis and three-column osteotomy use. Risk score categories, established via conditional inference tree (CIT)-derived thresholds were tested for cost-utility of rhBMP-2 usage, controlling for age, prior fusion, and baseline deformity and disability.

RESULTS

64% of ASD patients received rhBMP-2 (308/481). There were 17 (3.5%) patients that developed pseudarthrosis. rhBMP-2 use overall did not lower pseudarthrosis rates (OR: 0.5, [0.2-1.3]). Pseudarthrosis rates for each risk category were: No Risk (NoR) 0%; Low-Risk (LowR) 1.6%; Moderate Risk (ModR) 9.3%; High-Risk (HighR) 24.3%. Patients receiving rhBMP-2 had similar QALYs overall to those that did not (0.163 vs. 0.171, p = .65). rhBMP-2 usage had worse cost-utility in the LowR cohort (p < .001). In ModR patients, rhBMP-2 usage had equivocal cost-utility ($53,398 vs. $61,581, p = .232). In the HighR cohort, the cost-utility was reduced via rhBMP-2 usage ($98,328 vs. $211,091, p < .001).

CONCLUSION

Our study shows rhBMP-2 demonstrates effective cost-utility for individuals at high risk for developing pseudarthrosis. The generated score can aid spine surgeons in the assessment of risk and enhance justification for the strategic use of rhBMP-2 in the appropriate clinical contexts.

LEVEL OF EVIDENCE

III.

Treatment of adult spine deformity: A retrospective comparison of bone morphogenic protein and bone marrow aspirate with bone allograft

BACKGROUND  : The use of bone morphogenic protein (BMP-2) in adult spine deformity (ASD) surgery remains controversial more than two decades following its approval for clinical application in spine surgery. This study was performed to assess outcomes in patients undergoing ASD surgery with BMP application compared with a combination of bone marrow aspirate, cancellous bone chips and i-Factor.

METHODS

This was a retrospective cohort study. ASD patients were stratified by use of intra-operative BMP (BMP +) or not (BMA + I) and surveyed for the development of complications and mechanical failure. Quality of life gained following the procedure was evaluated using quality-adjusted life years (QALYs). Cost was calculated using the PearlDiver database and CMS definitions. Multivariable analyses (ANCOVA) and logistic regression were used to adjust for confounding.

RESULTS

512 patients were included (60% BMP +). At baseline, BMP + patients were older (62.5 vs 60.8 years, p < 0.010). Radiographic and quality-of-life metrics did not differ at follow up timepoints (all p > 0.05). BMP use was associated with higher supplemental rod use (OR: 7.0, 1.9 - 26.2, p = 0.004), greater number of levels fused (OR: 1.1, 1.03 - 1.17, p = 0.003) and greater neurological complications (OR: 5.0, 1.3 - 18.7, p = 0.017). Controlling for rod use and levels fused, BMP use was not associated with a lower risk of mechanical complications (OR 0.3, 95% CI: 0.2 - 3.0, p = 0.353), rod breakage (OR: 3.3, 0.6 - 18.7, p = 0.182) or implant failure (OR: 0.3, 0.04 - 1.51). At 2 years, the BMP + cohort exhibited higher overall costs ($108,062 vs $95,144, p = 0.002), comparable QALYs (0.163 vs 0.171, p = 0.65) and higher cost per QALY (p = 0.001) at two years.

CONCLUSIONS

In this analysis, BMP-2 application was not associated with superior outcomes when compared to a less costly biologic alternative (bone marrow aspirate + cancellous bone chips + i-Factor) following ASD surgery. The use of BMP-2 in ASD surgery appears to have reduced cost-efficacy at two years postoperatively.

A Narrative Review on Recombinant Human Bone Morphogenetic Protein 2: Where Are We Now?

Spinal fusion is a prevalent surgical intervention for degenerative spinal diseases, with increasing demand driven by ageing populations. The coexistence of multiple chronic conditions, termed multimorbidity, often complicates surgical outcomes, making advanced bone grafts crucial for successful fusions. This paper reviews the development, clinical application, and controversies surrounding the use of recombinant human bone morphogenetic protein-2 (rhBMP-2) in spinal fusion surgeries. A comprehensive narrative review was conducted, focusing on literature from January 1980 to January 2024, sourced from PubMed and Google Scholar. Studies included those examining rhBMP-2 specifically in spinal fusion contexts, excluding other bone morphogenetic proteins (BMPs) and non-spinal applications. This review presents an overarching synopsis of rhBMP-2, its development history and clinical efficacy, the emergence of side effects, and evolving patterns of clinical use. As discussed in this review, clinical practice has adjusted usage and dosages to mitigate adverse effects, yet the need for safer delivery mechanisms persists. rhBMP-2 remains a potent osteoinductive agent with comparable fusion success, as measured by radiographic fusion and good clinical outcomes, to autologous grafts but poses unique risks. This review sets out how further research is essential to optimise the delivery of rhBMP-2 to reduce side effects. Enhanced understanding and innovation of spatio-temporal presentation relative to endogenous BMP could significantly improve patient outcomes in spinal fusion surgeries. The review contributes to the growing body of literature on the use of rhBMP-2 in spine surgery and discusses changing patterns of clinical use over time.

Application of rhBMP in spinal fusion surgery: any correlation of cancer incidence? A systematic review and meta-analysis

PURPOSE

Safety concerns regarding the application of bone morphogenetic proteins (BMPs) have been highlighted in recent years. It is noted that both BMP and their receptors being identified as a trigger for cancer growth. Here, we aimed to determine the safety and efficacy of BMP for spinal fusion surgery.

METHODS

We conducted this systematic review on topics of spinal fusion surgery with rhBMP application from three database (PubMed, EuropePMC, and Clinicaltrials.gov) with MeSH phrases such as "rh-BMP," "rhBMP," "spine surgery," "spinal arthrodesis," and "spinal fusion" were searched (using the Boolean operators "and" and "or"). Our research includes all articles, as long as published in English language. In the face of disagreement between the two reviewers, we discussed it together until all authors reached a consensus. The primary key outcome of our study is the incidence of cancer following rhBMP implantation.

RESULTS

Our study included a total of 8 unique studies (n = 37,682). The mean follow-up varies among all studies, with the longest follow-up is 66 months. Our meta-analysis showed that exposure to rhBMP in spinal surgery did increase the risk of cancers (RR 1.85, 95%CI [1.05, 3.24], p = 0.03).

CONCLUSIONS

Our study found that rhBMP was not associated with the increased risk of cancer incidence within the rhBMP cohort. Still, we did face several limitations, in which further studies are needed to confirm the result of our meta-analysis.

Identification and verification of a BMPs-related gene signature for osteosarcoma prognosis prediction

BACKGROUND

This study aimed to get a deeper insight into new osteosarcoma (OS) signature based on bone morphogenetic proteins (BMPs)-related genes and to confirm the prognostic pattern to speculate on the overall survival among OS patients.

METHODS

Firstly, pathway analyses using Gene Ontology (GO) and the Kyoto Encyclopedia of Genes and Genomes (KEGG) were managed to search for possible prognostic mechanisms attached to the OS-specific differentially expressed BMPs-related genes (DEBRGs). Secondly, univariate and multivariate Cox analysis was executed to filter the prognostic DEBRGs and establish the polygenic model for risk prediction in OS patients with the least absolute shrinkage and selection operator (LASSO) regression analysis. The receiver operating characteristic (ROC) curve weighed the model's accuracy. Thirdly, the GEO database (GSE21257) was operated for independent validation. The nomogram was initiated using multivariable Cox regression. Immune infiltration of the OS sample was calculated. Finally, the three discovered hallmark genes' mRNA and protein expressions were verified.

RESULTS

A total of 46 DEBRGs were found in the OS and control samples, and three prognostic DEBRGs (DLX2, TERT, and EVX1) were screened under the LASSO regression analyses. Multivariate and univariate Cox regression analysis were devised to forge the OS risk model. Both the TARGET training and validation sets indicated that the prognostic biomarker-based risk score model performed well based on ROC curves. In high- and low-risk groups, immune cells, including memory B, activated mast, resting mast, plasma, and activated memory CD4 + T cells, and the immune, stromal, and ESTIMATE scores showed significant differences. The nomogram that predicts survival was established with good performance according to clinical features of OS patients and risk scores. Finally, the expression of three crucial BMP-related genes in OS cell lines was investigated using quantitative real-time polymerase chain reaction (qRT-PCR) and western blotting (WB).

CONCLUSION

The new BMP-related prognostic signature linked to OS can be a new tool to identify biomarkers to detect the disease early and a potential candidate to better treat OS in the future.

Failure in Adult Spinal Deformity Surgery: A Comprehensive Review of Current Rates, Mechanisms, and Prevention Strategies

STUDY DESIGN

Literature review.

OBJECTIVE

The aim of this review is to summarize recent literature on adult spinal deformity (ASD) treatment failure as well as prevention strategies for these failure modes.

SUMMARY OF BACKGROUND DATA

There is substantial evidence that ASD surgery can provide significant clinical benefits to patients. The volume of ASD surgery is increasing, and significantly more complex procedures are being performed, especially in the aging population with multiple comorbidities. Although there is potential for significant improvements in pain and disability with ASD surgery, these procedures continue to be associated with major complications and even outright failure.

METHODS

A systematic search of the PubMed database was performed for articles relevant to failure after ASD surgery. Institutional review board approval was not needed.

RESULTS

Failure and the potential need for revision surgery generally fall into 1 of 4 well-defined phenotypes: clinical failure, radiographic failure, the need for reoperation, and lack of cost-effectiveness. Revision surgery rates remain relatively high, challenging the overall cost-effectiveness of these procedures.

CONCLUSION

By consolidating the key evidence regarding failure, further research and innovation may be stimulated with the goal of significantly improving the safety and cost-effectiveness of ASD surgery.