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Study Design: Retrospective cohort study., Objective: To compare clinical outcomes, fusion rates, and rates of complications in posterior lumbar interbody fusions (PLIFs) and transforaminal lumbar interbody fusion procedures with either recombinant human bone morphogenetic protein-2 (rhBMP-2) and local bone graft (LBG) or LBG alone used as graft material., Summary of Background Data: rhBMP-2 is often used in PLIF and transforaminal lumbar interbody fusion procedures, but is associated with complications. Furthermore, recent evidence suggests that using LBG may be sufficient to induce fusion., Methods: All patients who underwent primary interbody fusions under a single surgeon were identified from the surgeon's records. In November 2008, the surgeon changed from routinely using LBG to using LBG and rhBMP-2 routinely, limiting selection bias. A retrospective review of prospectively collected data preoperatively and up to 12 months postoperatively was performed. Data collected included visual analogue scale, pain scores for back and leg, Oswestry Disability Index scores, Short-Form 36 (SF-36), standing lumbar radiographs, and clinical notes., Results: Seventy-seven patients met the study criteria and 70 consented to be part of the study. Fifty-one were treated with rhBMP-2 and 19 with LBG. At 12-month follow-up, no significant differences were seen in visual analogue scale score, Oswestry Disability Index score, or SF-36 scores. A total of 89.5% of the LBG group and 94.1% of the rhBMP-2 group went on to show radiographical evidence of fusion by 12-month follow-up (P = 0.61). The rhMBP-2 group had a higher complication rate (41.2% vs. 10.5%, incidence rate ratio = 3.91, P = 0.05)., Conclusion: In comparison we found no difference in clinical outcomes, comparable rates of fusion and a significant increase in complication rates with rhBMP-2. Using rhBMP-2 may unnecessarily increase the risk of complication in routine PLIF and transforaminal lumbar interbody fusion procedures., Level of Evidence: 3.

Background: Since the introduction of rhBMP-2 (Infuse) in 2002, surgeons have had an alternative substitute to autograft and its related donor site morbidity. Recently, the prevalence of reported adverse events and complications related to the use of rhBMP-2 has raised many ethical and legal concerns for surgeons. Additionally, the cost and decreasing reimbursement landscape of rhBMP-2 use have required identification of a viable alternative. Osteo allogeneic morphogenetic protein (OsteoAMP) is a commercially available allograft-derived growth factor rich in osteoinductive, angiogenic, and mitogenic proteins. This study compares the radiographic fusion outcomes between rhBMP-2 and OsteoAMP allogeneic morphogenetic protein in lumbar interbody fusion spine procedures., Methods: Three hundred twenty-one (321) patients from three centers underwent a transforaminal lumbar interbody fusion (TLIF) or lateral lumbar interbody fusion (LLIF) procedure and were assessed by an independent radiologist for fusion and radiographically evident complications. The independent radiologist was blinded to the intervention, product, and surgeon information. Two hundred and twenty-six (226) patients received OsteoAMP with autologous local bone, while ninety-five (95) patients received Infuse with autologous local bone. Patients underwent radiographs (x-ray and/or CT) at standard postoperative follow-up intervals of approximately 1, 3, 6, 12, and 18 months. Fusion was defined as radiographic evidence of bridging across endplates, or bridging from endplates to interspace disc plugs. Osteobiologic surgical supply costs were also analyzed to ascertain cost differences between OsteoAMP and rhBMP-2., Results: OsteoAMP produced higher rates of fusion at 6, 12, and 18 months (p ≤ 0.01). The time required for OsteoAMP to achieve fusion was approximately 40% less than rhBMP-2 with approximately 70% fewer complications. Osteobiologic supply costs were 80.5% lower for OsteoAMP patients (73.7% lower per level) than for rhBMP-2., Conclusions: Results of this study indicate that OsteoAMP is a viable alternative to rhBMP-2 both clinically and economically when used in TLIF and LLIF spine procedures.

Background: Recombinant human bone morphogenetic protein-2 (rhBMP-2) applied on an absorbable collagen sponge improves open tibial fracture-healing as an adjunct to unreamed intramedullary nail fixation. We evaluated rhBMP-2 and a new, injectable calcium phosphate matrix (CPM) formulation in acute closed tibial diaphyseal fractures treated with reamed intramedullary nail fixation., Methods: Patients were randomized (1:2:2:1) to receive standard of care, which consisted of definitive fracture fixation within seventy-two hours of injury with a locked intramedullary nail after reaming; standard of care and injection with 1.0 mg/mL of rhBMP-2/CPM; standard of care and injection with 2.0 mg/mL of rhBMP-2/CPM; or standard of care and injection with buffer/CPM, to evaluate the activity of the CPM delivery matrix and provide for sponsor and investigator blinding. The co-primary end points of the study were the effects of rhBMP-2/CPM on the time to fracture union (based on blinded assessment of radiographs) and the time to return to normal function (based on blinded assessment of the time to full weight-bearing without pain at the fracture site) compared with standard of care alone., Results: Three hundred and sixty-nine patients were randomized and included in the intent-to-treat population. This study was terminated after an interim analysis (180 patients with six months of follow-up) revealed no shortening in the time to fracture union in the active treatment arms compared with the standard of care control (the SOC group). In the final primary analysis, the median time to radiographic fracture union was not significantly different for the SOC (13.1 weeks), 1.0-mg/mL rhBMP-2/CPM (13.0 weeks), 2.0-mg/mL rhBMP-2/CPM (15.9 weeks), or buffer/CPM (15.4 weeks) treatment groups. The median time to pain-free full weight-bearing was also not significantly different among the SOC (13.4 weeks), 1.0-mg/mL rhBMP-2/CPM (13.4 weeks), 2.0-mg/mL rhBMP-2/CPM (14.3 weeks), and buffer/CPM (16.4 weeks) treatment groups., Conclusions: In patients with closed tibial fractures treated with reamed intramedullary nailing, the time to fracture union and pain-free full weight-bearing were not significantly reduced by rhBMP-2/CPM compared with standard of care alone. 24306696

Object: Iliac crest autograft has traditionally been considered the gold standard for lumbar spine fusion, though it is not without drawbacks related to harvesting site pain and other complications. Bone graft alternatives, such as recombinant human bone morphogenetic protein 2 (rh-BMP2), are now widely used but also have unique risk profiles and substantially increase costs. The purpose of the current study was to compare the efficacy of rh-BMP2 and synthetic silicate calcium phosphate (SiCaP) as bone graft substitutes on fusion rates and clinical outcomes in patients undergoing single-level lumbar stand-alone extreme lateral interbody fusion (XLIF)., Methods: A prospective, randomized, controlled, clinical, and radiographic study was performed at a single institution. Thirty patients with L4-L5 degenerative disc disease (DDD) were enrolled. Patients were randomized into one of two groups, 15 underwent lumbar single-level stand-alone XLIF using SiCaP, and 15 using rh-BMP2. Clinical and radiographic results were compared between the study groups. Pain (visual analogue scale) and disability (Oswestry disability index) were assessed preoperatively and at postoperative weeks 1 and 6 and postoperative months 3, 6, 12, 24, and 36. Radiographic evaluations were performed at 6, 12, 24, and 36 months. Neurological examinations and adverse events were recorded at each visit., Results: No intraoperative complications were observed in either treatment group, and clinical outcomes were similarly improved between bone graft substitutes from baseline to 36 months postoperative. Complications were transient hip flexion weakness (13%), insufficient indirect decompression (7%), subsidence (17%), excessive bone formation (4%), and adjacent segment disease (14%). Complication rates between the groups were similar, though with slightly more instances of subsidence in the SiCaP group and higher rates of excessive bone formation and adjacent segment disease in the rh-BMP2 group. Rates of fusion at different time points were different between the groups, with the SiCaP patients progressing more slowly toward solid fusion. However, at 36 months, 100% of patients undergoing XLIF achieved solid fusion., Conclusions: In stand-alone XLIF, SiCaP and rhBMP-2 bone graft substitutes both resulted in complete long-term fusion. rhBMP-2, however, seemed to result in more rapid early postoperative fusion, though with one instance of excessive bone formation in one patient that required subsequent surgical intervention., (Georg Thieme Verlag KG Stuttgart · New York.)

Background Context: Recombinant human bone morphogenetic protein-2 (rhBMP-2) (INFUSE, Medtronic, Memphis, TN, USA) has been used off-label for posterolateral lumbar fusions for many years., Purpose: The goal of this study was to evaluate the complications requiring reoperation associated with rhBMP-2 application for posterolateral lumbar fusions., Study Design/setting: During a 7-year period of time (2002-2009), all patients undergoing lumbar posterolateral fusion using rhBMP-2 (INFUSE) were retrospectively evaluated within a large orthopedic surgery private practice., Patient Sample: A total of 1,158 consecutive patients were evaluated with 468 (40.4%) males and 690 (59.6%) females., Outcome Measures: Complications related to rhBMP were defined as reoperation secondary to symptomatic failed fusion (nonunion), symptomatic seroma formation, symptomatic reformation of foraminal bone, and infection., Methods: Inclusion criteria were posterolateral fusion with rhBMP-2 implant and age equal to or older than 18 years. Surgical indications and treatment were performed in accordance with the surgeon's best knowledge, discretion, and experience. Patients consented to lumbar decompression and arthrodesis using rhBMP-2. All patients were educated and informed of the off-label utilization of rhBMP-2. Patient follow-up was performed at regular intervals of 2 weeks, 6 weeks, 12 weeks, 6 months, 1 year, and later if required or indicated., Results: Average age was 59.2 years, and body mass index was 30.7 kg/m². Numbers of levels fused were 1 (414, 35.8%), 2 (469, 40.5%), 3 (162, 14.0%), 4 (70, 6.0%), 5 (19, 1.6%), 6 (11, 0.9%), 7 (7, 0.6%), 8 (4, 0.3%), and 9 (2, 0.2%). Patients having complications requiring reoperation were 117 of 1,158 (10.1%): symptomatic nonunion requiring redo fusion and instrumentation 41 (3.5%), seroma with acute neural compression 32 (2.8%), excess bone formation with delayed neural compression 4 (0.3%), and infection requiring debridement 26 (2.2%). Nonunion was related to male sex and previous BMP exposure. Seroma formation was significantly higher in patients with higher doses of rhBMP-2 (p=.050) and with more than 12 mg of rhBMP-2 (χ(2)=0.025). Bone reformation and neural compression at the laminectomy and foraminotomy sites occurred in a delayed fashion. Infection was associated with obesity and respiratory disease. Infections were noted with a greater BMP dose (p<.001), more than 12 mg (χ(2)<0.001), fusion more than three levels (χ(2)<0.001), and reexposed to BMP (χ(2)=0.023)., Conclusions: rhBMP-2 utilization for posterolateral lumbar fusions has a low symptomatic nonunion rate. Prior rhBMP-2 exposure and male sex were related to symptomatic nonunion formation. rhBMP-2-associated neural compression acutely with seroma formation and delayed with foraminal bone formation is concerning and associated with higher rhBMP-2 concentrations., (Copyright © 2013 Elsevier Inc. All rights reserved.)

Study Design: A retrospective observational study., Objective: To assess clinical outcomes, perioperative complications, revision surgery rates, and recombinant human bone morphogenetic protein-2 (BMP-2)-related osteolysis, heterotopic bone, and unexplained postoperative radiculitis (BMPP) in a group of patients treated with BMP-2-augmented transforaminal lumbar interbody fusion (bTLIF) for the homogeneous diagnosis of discogenic pain syndrome (DPS) and to put forth the algorithm used to make the diagnosis., Summary of Background Data: There is a paucity of literature describing outcomes of TLIF for the homogeneous diagnosis of DPS, an old but controversial member of the lumbar degenerative disease family., Methods: The registry from a single surgeon was queried for patients who had undergone bTLIF for the homogeneous diagnosis of DPS, which was made via specific diagnostic algorithm. Clinical outcomes were determined by analyzing point improvement from typical outcome questionnaires and the data from Patient Satisfaction and Return to Work questionnaires. Independent record review was used to assess all outcomes., Results: Eighty percent of the cohort (36/45) completed preoperative and postoperative outcome questionnaires at an average follow-up of 41.9 ± 11.9 months, which demonstrated significant clinical improvement: Oswestry Disability Index = 16.4 (P < 0.0001), 12-Item Short Form Health Survey physical component summary score = 10.0 (P < 0.0001), and a Numeric Rating Scale for back pain = 2.3 (P < 0.0001). The median patient satisfaction score was 9.0 (10 = complete satisfaction), and 84.4% (27/32) of the cohort were able to return to their preoperative job, with or without modification. There were 3 perioperative complications, 4 revision surgical procedures, and 11 cases of benign BMPP. There were no incidents of the intraoperative dural tears or nerve root injury, and litigation involvement (11/36, P > 0.17), preoperative depression (15/36, P > 0.19) or prior discectomy/decompression (14/36, P < 0.37) was not a predictor of outcomes., Conclusion: Although limited by retrospective design and small cohort, the results of this investigation suggest that bTLIF is a reasonable treatment option for patients who experience DPS and affords high patient satisfaction. A larger study is needed to confirm these findings., Level of Evidence: 4.

Background Context: Recent reports of postoperative radiculitis, bone osteolysis, and symptomatic ectopic bone formation after recombinant human bone morphogenetic protein-2 (rhBMP-2) use in transforaminal lumbar interbody fusions (TLIFs) are a cause for concern., Purpose: To determine the clinical and radiographic complications associated with BMP utilization in a minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) environment., Study Design/setting: Retrospective clinical case series at a single institution., Patient Sample: Five hundred seventy-three consecutive patients undergoing an MIS-TLIF., Outcome Measures: Reoperation rates and total costs associated with complications of rhBMP-2 use and pseudarthrosis., Methods: A retrospective review of 610 consecutive patients undergoing an MIS-TLIF (2007-2010) by a single surgeon at our institution was performed (mean age 48.7 years, range 26-82 years). All patients underwent an MIS laminectomy with bilateral facetectomy, single TLIF cage, unilateral pedicle screw fixation, and 12 mg (large kit) or 4.2 mg (small kit) of rhBMP-2. The BMP-2 collagen-soaked sponge was placed anteriorly in the disc space, followed by local bone graft, and then the cage was filled only with local bone and no BMP-2. Patients were evaluated at 6 months and 1 year with computed tomography (CT) scan. Those demonstrating neuroforaminal bone growth, osteolysis/cage migration, or pseudarthrosis were reviewed, and cost data including direct cost/procedure for both index and revision surgeries were collected., Results: Of the 573 patients, 10 (1.7%) underwent 15 additional procedures based on recalcitrant radiculopathy and CT evidence of neuroforaminal bone growth, vertebral body osteolysis, and/or cage migration. Thirty-nine patients (6.8%) underwent reoperation for clinically symptomatic pseudarthrosis. Bone overgrowth was associated with nerve impingement and radiculopathy in all 10 patients (small kit, n=9; large kit, n=1). Osteolysis and cage migration occurred in 2 (20%) of these same 10 patients. Average total costs were calculated per procedure ($19,224), and the costs for reoperation equaled $14,785 per encounter for neuroforaminal bone growth and $20,267 for pseudarthrosis., Conclusions: Symptomatic ectopic bone formation, vertebral osteolysis, and pseudarthrosis are recognized complications with the use of rhBMP-2 in MIS-TLIFs. Potential causes include improper dosage and a closed space that prevents the egress of the postoperative BMP-2 fluid collection. Management of these complications has a substantial cost for the patient and the surgeon and needs to be considered with the off-label use of rhBMP-2., (Copyright © 2013 Elsevier Inc. All rights reserved.)

Study Design: A rodent model of posterior spinal fusion., Objective: The aim of this study was to evaluate the efficacy of low-dose recombinant human bone morphogenetic protein-2 (rhBMP-2) delivered with a heparin based polylectrolyte complex (PEC) carrier in facilitating posterior spinal fusion while concurrently minimizing seroma and heterotopic ossification., Summary of Background Data: rhBMP-2 is being used to augment spinal fusion. However, complications such as heterotopic ossification and local soft tissue swellings have been reported. These are attributed to supraphysiological amount of rhBMP-2 and the poor modulation capacity of absorbable collagen sponge., Methods: Forty rats were randomized into 6 groups as follows. Group I: absorbable collagen sponge without rhBMP-2 (n = 4); group II: positive control, absorbable collagen sponge + 10 μg rhBMP-2 (n = 4); group III: alginate-(poly-L-lysine)-heparin (PEC) without rhBMP-2 (n = 8); group IV: PEC + 4.5 μg rhBMP-2 (n = 8); group V: PEC + 1.5 μg rhBMP-2 (n = 8); group VI: PEC + 0.5 μg rhBMP-2 (n = 8)., Results: Between postoperative days 5 and 7, seroma was observed in all rhBMP-2 implanted groups irrespective of carrier and dose. However, the rate and size of seroma differed considerably. Although all animals (100%) in positive control group showed seroma, only one animal (12.5%) in group VI developed seroma at the implant site. The size of seroma in group VI was significantly smaller than that in positive control group. Micro-computed tomography evaluation revealed comparable mean fusion scores in all rhBMP-2 implanted groups. More importantly, although new bone was well contained within the cage in group VI, heterotopic ossification beyond the cage was observed in positive control group., Conclusion: A new carrier has demonstrated capacity to minimize seroma formation as well as heterotopic ossification associated with rhBMP-2 by reducing the efficacious dose needed for consistent fusion. The results of this study indicate that PEC alginate microbeads may represent a new opportunity to define an efficient rhBMP-2 carrier.

Background: Encapsulating peritoneal sclerosis (EPS) is a rare but devastating complication of peritoneal dialysis. The etiology is unclear, but genetic predisposition may be a contributing factor. We used adenovirus-mediated gene transfer of transforming growth factor (TGF) β1 to the peritoneum in four genetically distinct laboratory mouse strains to assess differences in fibrogenic response., Methods: Mice from four genetic backgrounds (C57BL/6J, DBA/2J, C3H/HeJ and SJL/J) received an intraperitoneal injection of an adenovirus expressing TGFβ1 (AdTGFβ1) or control adenovirus (AdDL) and were assessed 4 and 10 days after infection. Submesothelial thickening, angiogenesis and gene expression were quantified from peritoneal tissue. Protein was extracted from omental tissue and assessed for collagen, E-cadherin and TGFβ signaling pathway proteins., Results: There was a graded response among the mouse strains to the peritoneal overexpression of TGFβ1. TGFβ1 induced a significant fibrogenic response in the C57BL/6J mice, whereas the SJL/J mice were resistant. The DBA/2J and the C3H/HeJ mice had intermediate responses. A similar graded response was seen in collagen protein levels in the omental tissue and in fibrosis-associated gene expression. TGFβ type 1 receptor and SMAD signaling pathways appeared to be intact in all the mouse strains., Conclusions: There were significant differences in mouse strain susceptibility to peritoneal fibrosis, suggesting that genetic factors may play a role in the development of peritoneal fibrosis and possibly EPS. As early TGFβ1 signaling mechanisms appear to be intact, we hypothesize that fibrosis resistance in the SJL/J mice lies further down the wound-healing cascade or in an alternate, non-SMAD pathway.

Objective: To investigate whether published results of industry funded trials of recombinant human bone morphogenetic protein 2 (rhBMP-2) in spinal fusion match underlying trial data by comparing three different data sources: individual participant data, internal industry reports, and publicly available journal publications and conference abstracts., Data Collection and Synthesis: The manufacturer of rhBMP-2 products (Medtronic; Minneapolis, MN) provided complete individual participant data and internal reports for all its studies of rhMBP-2 in spinal fusion. We identified publications and conference abstracts through comprehensive literature searches. We compared outcomes provided in the individual participant data against outcomes reported in publications. For effectiveness outcomes, we compared meta-analyses of randomised controlled trials based on each of the three data sources. For adverse events, meta-analysis of the published aggregate data was not possible and we compared the number and type of adverse events reported between data sources., Results: 32 publications reported outcomes from 11 of the 17 existing manufacturer sponsored studies. For individual randomised controlled trials, 56% (9/16) to 88% (15/17) of effectiveness outcomes known to have been collected were reported in the published literature. Meta-analyses of effectiveness data were almost identical for pain outcomes and similar for fusion across the three data sources. A minority of adverse event data known to have been collected were reported in the published literature. Several journal articles reported only "serious," "related," or "unanticipated" adverse events, without defining these terms. Others reported a small proportion of the collected adverse event categories. Around 23% (533/2302) of the total adverse events collected in published randomised controlled trials have been reported in the literature, with randomised controlled trials evaluating the licensed preparation (Infuse) reporting around 11% (122/1108) of collected adverse events., Conclusions: The published literature only partially represents the total data known to have been collected on the effects of rhBMP-2. This did not lead to substantially different results for meta-analysis of effectiveness outcomes. In contrast, reporting of adverse event data in trial publications was inadequate and inconsistent to the extent that any systematic review based solely on the publicly available data would not be able to properly evaluate the safety of rhBMP-2. Analysis of individual participant data enabled the most complete, detailed, and in-depth analysis and was not more resource intensive than extracting, collating, and analysing aggregate data from multiple trial publications and conference abstracts. Confidential internal reports presented considerably more adverse event data than publications, and in the absence of individual participant data access to these reports would support more accurate and reliable investigation, with less time and effort than relying on incomplete published data.

Background: Recombinant human bone morphogenetic protein-2 (rhBMP-2) is widely used to promote fusion in spinal surgery, but its safety has been questioned., Purpose: To evaluate the effectiveness and safety of rhBMP-2., Data Sources: Individual-participant data obtained from the sponsor or investigators and data extracted from study publications identified by systematic bibliographic searches through June 2012., Study Selection: Randomized, controlled trials of rhBMP-2 versus iliac crest bone graft (ICBG) in spinal fusion surgery for degenerative disc disease and related conditions and observational studies in similar populations for investigation of adverse events., Data Extraction: Individual-participant data from 11 eligible of 17 provided trials sponsored by Medtronic (Minneapolis, Minnesota) (n = 1302) and 1 of 2 other eligible trials (n = 106) were included. Additional aggregate adverse event data were extracted from 35 published observational studies., Data Synthesis: Primary outcomes were pain (assessed with the Oswestry Disability Index [ODI] or Short Form-36), fusion, and adverse events. At 24 months, ODI scores were 3.5% lower (better) with rhBMP-2 than with ICBG (95% CI, 0.5% to 6.5%) and radiographic fusion was 12% higher (CI, 2% to 23%). At or shortly after surgery, pain was more common with rhBMP-2 (odds ratio, 1.78 [CI, 1.06 to 2.95]). Cancer was more common after rhBMP-2 (relative risk, 1.98 [CI, 0.86 to 4.54]), but the small number of events precluded definite conclusions., Limitation: The observational studies were diverse and at risk of bias., Conclusion: At 24 months, rhBMP-2 increases fusion rates, reduces pain by a clinically insignificant amount, and increases early postsurgical pain compared with ICBG. Evidence of increased cancer incidence is inconclusive., Primary Funding Source: Yale University Open Data Access Project.

Background: Recombinant human bone morphogenetic protein-2 (rhBMP-2) is used as a bone graft substitute in spinal fusion, which unites (fuses) bones in the spine. The accuracy and completeness of journal publications of industry-sponsored trials on the effectiveness and harms of rhBMP-2 has been called into question., Purpose: To independently assess the effectiveness and harms of rhBMP-2 in spinal fusion and reporting bias in industry-sponsored journal publications., Data Sources: Individual-patient data (IPD) from 17 industry-sponsored studies; related internal documents; and searches of MEDLINE (1996 to August 2012), other databases, and reference lists., Study Selection: Randomized, controlled trials (RCTs) and cohort studies of rhBMP-2 versus any control and uncontrolled studies of harms., Data Extraction: Effectiveness outcomes in IPD were recalculated using consistent definitions. Study characteristics and results were abstracted by 1 investigator and confirmed by another. Two investigators independently assessed quality using predefined criteria., Data Synthesis: Thirteen RCTs and 31 cohort studies were included. For lumbar spine fusion, rhBMP-2 and iliac crest bone graft were similar in overall success, fusion, and other effectiveness measures and in risk for any adverse event, although rates were high across interventions (77% to 93% at 24 months from surgery). For anterior lumbar interbody fusion, rhBMP-2 was associated with nonsignificantly increased risk for retrograde ejaculation and urogenital problems. For anterior cervical spine fusion, rhBMP-2 was associated with increased risk for wound complications and dysphagia. At 24 months, the cancer risk was increased with rhBMP-2 (risk ratio, 3.45 [95% CI, 1.98 to 6.00]), but event rates were low and cancer was heterogeneous. Early journal publications misrepresented the effectiveness and harms through selective reporting, duplicate publication, and underreporting., Limitations: Outcome assessment was not blinded, and ascertainment of harms in trials was poor. No trials were truly independent of industry sponsorship., Conclusion: In spinal fusion, rhBMP-2 has no proven clinical advantage over bone graft and may be associated with important harms, making it difficult to identify clear indications for rhBMP-2. Earlier disclosure of all relevant data would have better informed clinicians and the public than the initial published trial reports did., Primary Funding Source: Yale University and Medtronic.

Study Design: Retrospective review of prospectively collected data., Objective: To evaluate long-term clinical outcomes and complications of the transforaminal lumbar interbody fusion (TLIF) procedure from a large consecutive series, without industry funding. Clinical outcomes and complications are analyzed by diagnosis and primary versus revision surgery to assess whether TLIF with bone morphogenic protein (BMP) is appropriate for common use in deformity, spondylolisthesis, and degenerative disease., Summary of Background Data: A common method for achieving spinal arthrodesis includes TLIF with a cage and off-label interbody BMP-2, supported by posterior arthrodesis and a pedicle screw construct. There are no large studies analyzing outcomes and complications after TLIF in different diagnoses, for primary and revision surgery, leading some to question the widespread use of TLIF., Methods: A total of 509 consecutive adults underwent open posterior instrumented fusion, augmented with TLIF at 872 discs using a cage and rhBMP-2, with minimum 2-year follow-up. Cohort diagnoses included 179 degenerative, 207 spondylolisthesis, and 123 deformity patients. Patient age averaged 61 years, 207 had undergone prior decompression or fusion surgery. All patients underwent posterior instrumented fusion and pedicle screw instrumentation at average 3.6 levels (range, 1-16); all patients had TLIF 1.7 levels (range, 1-4 levels) with BMP and autograft, stabilized with an interbody cage., Results: At average 59 months follow-up, 12 patients developed pseudoarthrosis, 8 at TLIF levels (8/872 discs, 0.92%) most commonly at L5-S1 (6/8). Significant clinical improvement was noted in patients with deformity, spondylolisthesis, and degenerative disease undergoing primary and revision surgery. Overall, visual analogue scale preoperative score was 6.6, at 1 year 3.8, at 2 years 3.5 (P < 0.001) and the preoperative ODI was 50.9, at 1 year 36.1, and at 2 years 35.0 (P < 0 0.001). Pain medication requirements also declined., Conclusion: The efficacy of TLIF with BMP is supported in this large series with long-term follow-up, independent of industry. Reliable fusion and improved outcomes can be expected in adults undergoing TLIF for deformity, spondylolisthesis, and degenerative disease. Most complications occurred in patients with deformity., Level of Evidence: 3.

Study Design: Retrospective review of prospectively collected data., Objective: Without industry funding, the study evaluated short- and long-term complications related to off-label bone morphogenetic protein (BMP) used with transforaminal lumbar interbody fusion (TLIF) from a large consecutive series. Complications and results were analyzed by BMP dose, fusion length, and primary versus revision surgery. Based on the results, surgical technique and BMP dose recommendations were proposed., Summary of Background Data: Off-label use of BMP in TLIF, although common, has only been studied in small series and case reports using various techniques, cage types, and doses of BMP. Several of these studies have reported minimal complications. Others report problems related to BMP, which has led to questions regarding current widespread use of TLIF with BMP., Method: TLIF with rhBMP-2 was performed at 872 discs in 509 consecutive adults who underwent open posterior instrumented fusion and had minimum 2-year follow-up; diagnoses included degenerative disease (179), spondylolisthesis (207), deformity (123). Patient age averaged 61 years: 12% were smokers and 41% had revision surgery. TLIF was performed at 1.7 levels: single level: 229, 2 levels: 201, 3 levels: 74, 4 levels: 5. Local autograft was used for backfill around and behind each rectangular cage. Varying doses of interbody BMP were used at an average 7.3 mg per disc (range: 2-12 mg per disc)., Results: At 5 years average follow-up, 8 patients developed pseudoarthrosis at levels of TLIF (8 of 872 discs, 0.92%). Seroma (0.4%) and ectopic bone growth (0.6%) were too infrequent to be associated with a particular BMP dose. Deep infection was 2.6% overall (1.7% of the degenerative group). Symptomatic osteolysis or cage subsidence did not occur. Significant long-term improvement was noted in clinical and functional outcomes compared with preoperation., Conclusion: Five-year follow-up after TLIF with BMP, independent of industry, confirms effective arthrodesis in short and long fusions, both primary and revision. Most complications occurred in deformity patients. BMP-related complications (seroma, ectopic bone) were rare., Level of Evidence: 3.

Recombinant human bone morphogenetic protein-2 (rhBMP-2) promotes the induction of bone growth and is widely used in spine surgery to enhance arthrodesis. Recombinant human BMP-2 has been associated with a variety of complications including ectopic bone formation, adjacent-level fusion, local bone resorption, osteolysis, and radiculitis. Some of the complications associated with rhBMP-2 may be the result of rhBMP-2 induction of the inflammatory host response. In this paper the authors report on a patient with prior transforaminal lumbar interbody fusion (TLIF) using an interbody cage packed with rhBMP-2, in which rhBMP-2 possibly contributed to vascular injury during an attempted anterior lumbar interbody fusion. This 63-year-old man presented with a 1-year history of worsening refractory low-back pain and radiculopathy caused by a Grade 1 spondylolisthesis at L4-5. He underwent an uncomplicated L4-5 TLIF using an rhBMP-2-packed interbody cage. Postoperatively, he experienced marginal improvement of his symptoms. Within the next year and a half the patient returned with unremitting low-back pain and neurogenic claudication that failed to respond to conservative measures. Radiological imaging of the patient revealed screw loosening and pseudarthrosis. He underwent an anterior retroperitoneal approach with a plan for removal of the previous cage, complete discectomy, and placement of a femoral ring. During the retroperitoneal approach the iliac vein was adhered with scarring and fibrosis to the underlying previously operated L4-5 interbody space. During mobilization the left iliac vein was torn, resulting in significant blood loss and cardiac arrest requiring chest compression, defibrillator shocks, and blood transfusion. The patient was stabilized, the operation was terminated, and he was transferred to the intensive care unit. He recovered over the next several days and was discharged at his neurological baseline. The authors propose that the rhBMP-2-induced host inflammatory response partially contributed to vessel fibrosis and scarring, resulting in the life-threatening vascular injury during the reoperation. Spine surgeons should be aware of this potential inflammatory fibrosis in addition to other reported complications related to rhBMP-2.

Study Design: This was a prospective study evaluating the incidence of retrograde ejaculation (RE) after anterior lumbar interbody fusion (ALIF) based on laboratory analysis of semen and urine., Objective: The purpose of this study was to investigate the incidence of RE based on quantitative semen analysis and to compare the rate with that identified using a standardized qualitative questionnaire administered by telephone., Summary of Background Data: RE is a specific sexual dysfunction in which semen passes into the bladder during ejaculation. It has long been a known possible complication of ALIF associated with injury to the superior hypogastric plexus occurring during access to the anterior lumbar spine. Although reported in multiple studies, there is no standardized assessment for RE and many studies do not describe the methods by which it was assessed. Recently, there has been increased interest in ALIF-related RE with respect to the use of recombinant human bone morphogenetic protein (rhBMP-2). However, how RE was diagnosed remains loosely defined. One possible assessment of RE is to analyze semen and urine after ejaculation., Methods: Forty-one male patients undergoing ALIF with posterior pedicle screw instrumentation and fusion at L4-L5 and/or L5-L1 consented to participate in the study. The subjects went to a cryobank for preoperative semen and postejaculatory urine analysis. They returned to the cryobank 3 to 6 months after surgery for repeat testing. The semen analysis consisted of ejaculate volume, total sperm count, concentration, and motility, whereas the urine test reported postejaculatory voided urine for spermatozoa. Postoperatively, patients were called by the principle investigator who conducted an interview based on a standardized questionnaire (completed for 36 patients). Patients were considered to have RE based on the questionnaire if they reported less or no ejaculate fluid. These results were compared with those from the laboratory testing to evaluate the value of the questionnaire in assessing RE. rhBMP-2 was used in 21 of the cases. The incidence of RE was compared in these patients versus those in whom rhBMP-2 was not used., Results: Four patients (9.8%) were diagnosed with RE based on the laboratory analysis, 2 of which resolved spontaneously. Based on the questionnaire, 15 (41.7%) patients reported having RE, including the 4 that were confirmed by laboratory testing. Of the 21 patients treated with rhBMP-2, 2 (9.5%) were diagnosed with RE, 1 of which resolved. Of the 20 patients treated without rhBMP-2, 2 (10.0%) had RE, 1 of which resolved., Conclusion: This study suggests that use of a questionnaire tends to overestimate the incidence of RE as compared with the quantitative semen and urine analysis. Contrary to recent studies using retrospective qualitative review, in this small group with quantitative analysis, use of rhBMP-2 was not related to an increased incidence of RE, with a rate of approximately 10% in both patients receiving, and those not receiving, rhBMP-2. Further study of a larger group using preoperative semen and urine analysis, postoperative standard questionnaire and postoperative semen analysis should be pursued to further investigate the occurrence of RE and to possibly assist in developing and validating a questionnaire for RE assessment.

Study Design: In vivo rodent model., Objective: Investigate the effect of systemic corticosteroid administration on soft-tissue inflammation after local delivery of recombinant human bone morphogenetic protein-2 (rhBMP-2)., Summary of Background Data: Corticosteroid use in cases of soft-tissue inflammation associated with the use of rhBMP-2 has been reported in clinical studies, but the effectiveness of its use and appropriate timing remain unclear., Methods: Absorbable collagen sponges were implanted with control or rhBMP-2 into the lumbar region of rats subcutaneously and intramuscularly. Four groups were studied: group I, control sponge only; group 2, BMP-2 sponge only; group III, BMP-2 sponge and preoperative intraperitoneal methylprednisolone (MPSS); group IV, BMP-2 sponge with MPSS given on day 2. Using magnetic resonance imaging, inflammation was assessed in terms of soft tissue edema volume at 0, 2, 4, and 7 days. Rats were sacrificed after 7 days for gross and histological analysis., Results: The peak mean intramuscular inflammatory volume occurred on day 2 in all groups. Group II (BMP-2 without MPSS) had a significantly higher peak mean inflammatory volume (405.46 mm) on day 2 than that of groups I (266 mm), III (278 mm), and IV (291 mm) (P = 0.001). No significant difference in intramuscular soft-tissue inflammation was observed between the control group and the groups receiving MPSS on day 0 or day 2 at any time point. No differences in the area of inflammatory cell infiltrate surrounding the sponge was observed histologically, after sacrificing them, in groups treated with BMP-2., Conclusion: Systemic MPSS administration reduced soft tissue edema associated with rhBMP-2 as measured by magnetic resonance imaging, but no effect was observed on the histological area of inflammation. Further studies are required to elucidate if there is any benefit to the use of corticosteroid administration in reducing the area of inflammation associated with the use of rhBMP-2.

Object: The aim of this study was to determine the incidence and assess specific risk factors in the postoperative development of retrograde ejaculation (RE) in men treated for degenerative lumbar disc disease at the L4-5 or L5-S1 level with stand-alone anterior interbody implants with or without recombinant human bone morphogenetic protein-2 (rhBMP-2)., Methods: Patients enrolled in 5 prospective, randomized, multicenter FDA-approved investigational device exemption studies were observed for a minimum of 2 years to assess the rate of RE. Five hundred eight men with symptomatic single-level lumbar degenerative disc disease with up to Grade 1 spondylolisthesis underwent anterior lumbar interbody surgery with stand-alone anterior implants at either L4-5 or L5-S1. All patient self-reported and physician-documented adverse events were recorded over the entire course of follow-up. In the investigational groups, 207 patients were treated with an open surgical procedure using dual paired constructs and rhBMP-2 on an absorbable collagen sponge. The control groups (n = 301) were treated with lumbar fusion cage implants and iliac crest autograft or a metal-on-metal disc arthroplasty device. Multivariate analyses of RE were performed to assess the influence of treatment (rhBMP-2), surgical approach, and treated level. Data were analyzed for each trial individually and for the data pooled from the 5 trials., Results: Retrograde ejaculation occurred at the highest rates in the earliest clinical trial. Of the 146 men, 6 (4.1%) developed RE postoperatively. In subsequent studies, the rates of RE ranged from 0% to 2.1%. Combining the data from the 5 trials, RE was reported in 7 (3.4%) of the 207 patients who received the rhBMP-2 treatment compared with 5 (1.7%) of the 301 patients who received the autograft or lumbar disc treatment (p = 0.242, Fisher exact test). Cases of RE were reported in 7 (1.6%) of 445 patients who underwent a retroperitoneal spinal exposure; 5 RE cases were reported in 58 patients (8.6%) who underwent a transperitoneal approach. The difference in surgical approaches was significant (p = 0.007, Fisher exact test). There was no difference in the rate of RE based on the lumbar level exposed (p = 0.739). Multivariate analyses were consistent with the conclusions from Fisher exact tests. In the initial rhBMP-2 trial, after adjusting for effects of surgical approach and treated level, the difference in RE between the treatment groups (rhBMP-2 vs autograft or disc arthroplasty) was not significant (p = 0.177); however, the difference in RE between the retroperitoneal and transperitoneal approaches was significant (p = 0.029)., Conclusions: In these 5 prospective randomized trials involving anterior lumbar interbody surgery, the use of rhBMP-2 was associated with a higher incidence of RE (3.4% vs 1.7%) but did not reach statistical significance. Based on surgical approach, the difference in rates of RE was statistically significant. This study reports on the outcomes of 5 prospective randomized FDA-approved investigational device exemption trials. Registration for studies became law in 2007. Four of these trials were completed before the law went into effect. The registration number for the lumbar disc arthroplasty trial is NCT00635843.

Object: The goal of this study was to compare the urological complications in patients after anterior lumbar interbody fusion (ALIF) with and without the use of recombinant human bone morphogenetic protein-2 (rhBMP-2)., Methods: The authors retrospectively reviewed the medical records of all patients who underwent ALIF with and without rhBMP-2 between January 2002 and August 2010. Patient demographic, operative, and complication information was analyzed. Male patients who underwent ALIF between L-4 and S-1 were contacted to assess postoperative urological complications., Results: Of the 110 male patients who underwent ALIF and were included in this study, 59 were treated with rhBMP-2 and 51 did not receive rhBMP-2. The mean follow-up duration was 17.5 months for the rhBMP-2 group and 30.8 months for the control group. No difference was found regarding the total number of urological complications in the rhBMP-2 group versus the control group (22% vs 20%, respectively; p = 1.0) or for retrograde ejaculation specifically (8% vs 8%, respectively; p = 1.0)., Conclusions: In this study, the use of rhBMP-2 with ALIF surgery was not associated with an increased incidence of urological complications and retrograde ejaculation when compared with control ALIF without rhBMP-2. Further prospective analyses that specifically look at these complications are warranted.

Study Design: Retrospective cohort study of 1430 patients undergoing lumbar spinal fusion from 2002 - 2009., Objective: The goal of this study was to compare and evaluate the number of complications requiring reoperation in elderly versus younger patients., Summary of Background Data: rhBMP-2 has been utilized off label for instrumented lumbar posterolateral fusions for many years. Many series have demonstrated predictable healing rates and reoperations. Varying complication rates in elderly patients have been reported., Materials and Methods: All patients undergoing instrumented lumbar posterolateral fusion of ≤ 3 levels consenting to utilization of rhBMP-2 were retrospectively evaluated. Patient demographics, body mass index, comorbidities, number of levels, associated interbody fusion, and types of bone void filler were analyzed. The age of patients were divided into less than 65 and greater than or equal to 65 years. Complications related to the performed procedure were recorded., Results: After exclusions, 482 consecutive patients were evaluated with 42.1% males and 57.9% females. Average age was 62 years with 250 (51.9%) < 65 and 232 (48.1%) ≥ 65 years. Patients ≥ 65 years of age stayed longer (5.0 days) in the hospital than younger patients (4.5 days) (p=0.005).Complications requiring reoperation were: acute seroma formation requiring decompression 15/482, 3.1%, bone overgrowth 4/482, 0.8%, infection requiring debridement 11/482, 2.3%, and revision fusion for symptomatic nonunion 18/482, 3.7%. No significant differences in complications were diagnosed between the two age groups. Statistical differences were noted between the age groups for medical comorbidities and surgical procedures. Patients older than 65 years underwent longer fusions (2.1 versus 1.7 levels, p=0.001)., Discussion: Despite being older and having more comorbidities, elderly patients have similar complication and reoperation rates compared to younger healthier patients undergoing instrumented lumbar decompression fusions with rhBMP-2.

Object: Reported complications of recombinant human bone morphogenetic protein-2 (rhBMP-2) use in anterior cervical discectomy and fusion (ACDF) cases include dysphagia and cervical swelling. However, dysphagia often occurs after multilevel ACDF procedures performed with allograft (without BMP) as well. To date, there has been no large study comparing the dysphagia rates of patients who have undergone multilevel ACDF using allograft spacers with those who underwent ACDF using polyetheretherketone (PEEK) cages filled with rhBMP2. The authors report one of the first such comparisons between these 2 patient cohorts., Methods: The authors retrospectively reviewed 150 patient records. Group 1 (BMP group) consisted of 100 patients who underwent multilevel ACDF with PEEK cages filled with rhBMP-2 and instrumented with a cervical plate. Group 2 (allograft group) included a matched control cohort of 50 patients who underwent multilevel ACDF with allograft spacers and anterior plate fixation (without rhBMP-2). Patient demographics were not significantly different between the groups. Fusion was assessed by means of dynamic radiographs and/or CT at routine intervals. Complications, dysphagia incidence, standardized dysphagia score, Nurick grades, and fusion rates were assessed., Results: The mean follow-up for the BMP group (Group 1) was 35 months while the mean follow-up for the allograft group (Group 2) was 25 months. There was a complication rate of 13% in the BMP group compared with 8% in the allograft group (p < 0.005). There was no significant difference in overall dysphagia incidence between the BMP group and the allograft group (40% vs 44%, respectively; p > 0.05). However, there was a significant difference in the severity of dysphagia (using the SWAL-QOL dysphagia scoring system) between the 2 groups: 0.757 for the BMP group versus 0.596 for the allograft group (p < 0.005). In subgroup analysis, the use of rhBMP-2 significantly increased the severity of dysphagia in patients undergoing 2-level ACDF (p < 0.005). However, the severity of dysphagia did not differ significantly between groups when 3- or 4-level ACDF cases were compared. There was no pseudarthrosis in Group 1 (the BMP group) compared with a 16% pseudarthrosis rate in Group 2 (the allograft group) (p < 0.05). There was a weak correlation between the total rhBMP-2 dose and the dysphagia score (Kendall tau rank correlation coefficient 0.166, p = 0.046)., Conclusions: The use of rhBMP-2 in patients undergoing 2-level ACDF significantly increases the severity of dysphagia (dysphagia score) without affecting the overall incidence of dysphagia. However, there is no statistically significant difference in the incidence or severity of dysphagia between patients undergoing 3-level or 4-level ACDF treated with PEEK/rhBMP-2 and those treated with only allograft. The use of rhBMP-2 appears to reduce the risk of pseudarthrosis. This benefit is most pronounced in patients who undergo 4-level ACDF and are smokers.

Background: Transient bone resorption limits the use of recombinant human bone morphogenetic protein-2 (rhBMP-2)/absorbable collagen sponge in metaphyseal bone. The purpose of the present study was to evaluate the efficacy of rhBMP-2/calcium phosphate matrix (CPM) to induce bone formation while limiting transient bone resorption in nonhuman primate core defects., Methods: Metaphyseal core defects were created in eighteen cynomolgus monkeys. rhBMP-2 retention was evaluated in the distal part of the radius. Bone formation was evaluated at eight weeks following treatment with 1.5 or 4.5-mg/mL rhBMP-2/CPM, CPM alone, or no treatment in the distal part of the radius, the proximal part of the tibia, and the proximal part of the femur; at twenty-four weeks following treatment with 1.5-mg/mL rhBMP-2/CPM or CPM alone in the proximal part of the tibia; and at one, two, and four weeks following treatment with 1.5-mg/mL rhBMP-2/CPM or no treatment in the distal part of the radius. Bone resorption was evaluated at four weeks following treatment with 1.5, 2.0, 3.0, and 4.5-mg/mL rhBMP-2/CPM or CPM alone in the distal part of the femur. Evaluations were performed with use of scintigraphy, radiographs, histological analysis, and computed tomography., Results: Seventy-eight percent, 64%, 50%, 35%, and 12% of the rhBMP-2 was retained in the distal part of the radius at one, seven, fourteen, twenty-one, and forty-nine days after surgery. rhBMP-2/CPM increased bone formation within core defects and surrounding trabeculae compared with CPM alone or no treatment at all anatomic locations at eight weeks, and bone formation was ongoing in the rhBMP-2/CPM-treated proximal tibial sites at twenty-four weeks. Bone formation began in the trabeculae surrounding the core defects at one week and was observed adjacent to the resorbing CPM within the core defects and in the surrounding trabecular bone at two and four weeks in the rhBMP-2/CPM-treated distal radial sites. Bone formation was confined to the region immediately surrounding the core defects in the untreated distal radial sites at all time points. Transient bone resorption was only observed in the distal femoral sites treated with 4.5 mg/mL of rhBMP-2/CPM at two weeks., Conclusions: Treatment of nonhuman primate metaphyseal core defects with 1.5 to 3.0-mg/mL rhBMP-2/CPM resulted in bone formation without transient bone resorption., Clinical Relevance: rhBMP-2/CPM may be useful to accelerate healing of metaphyseal bone defects in humans.

Background Context: Adverse effects of recombinant human bone morphogenetic protein-2 (rhBMP-2) in spinal surgery have previously been observed. However, because of its size, scope, and nature, the US Food and Drug Administration's database of postmarketing reports is useful for detecting new and unexpected safety concerns., Purpose: To characterize adverse events reported to the FDA; to characterize off-label use of rhBMP-2., Study Design: Review of adverse events reported to the FDA after the use of rhBMP-2 (INFUSE Bone Graft) in spinal surgery., Methods: The Manufacturer and User Facility Device Experience database was searched for the brand name "infuse bone graft," for reports received from July 2, 2002, through August 31, 2011. Adverse events were reviewed, summarized, and classified by an MD. For each report, the most important clinical entity was identified as the principal adverse event. Off-label uses were summarized., Results: Of 834 reports, four (0.5%) described procedures in which rhBMP-2 was used in accordance with the approved indication. Nearly half of all the reports, 370 (44.4%), stated that the patient required revision surgery or other invasive interventions to address the reported adverse event. Swelling, fluid collections, osteolysis, pain/radiculopathy, heterotopic bone, pseudarthrosis, surgical site infections and other wound complications, thromboembolic events, respiratory distress, cancer, and other events were reported., Conclusions: Because of their duration, scope, and expense, prospective studies designed to estimate the risk of rare adverse events may be impractical. Despite its imperfections, postmarketing surveillance helps to narrow the focus by revealing patterns and prioritizing topics for further research. One should not extrapolate from these results to the rhBMP-2 experience as a whole; the findings reported here might not be representative. This analysis indicates that serious adverse events can occur after the use of rhBMP-2 in spinal surgery and raises many points that surgeons may wish to consider when deciding when and how to use this product in their patients., (Published by Elsevier Inc.)

Background Context: Retrograde ejaculation (RE) is a complication of anterior lumbar interbody fusion (ALIF) techniques. Most commonly, this results from mechanical or inflammatory injury to the superior hypogastric plexus near the aortic bifurcation. Bone morphogenetic protein-2 (BMP-2) has been used in spinal fusions and has been associated with inflammatory and neuroinflammatory adverse reactions, which may contribute to RE development after anterior lumbar surgery., Purpose: While controlling for anterior approach technique, we compared the incidence of RE with and without rhBMP-2 exposure, in large, matched cohorts of patients after ALIF., Study Design: Retrospective analysis of 10 years of prospectively gathered outcomes data on consecutive-patient cohorts having the same anterior exposure technique for ALIF with and without rhBMP-2 use., Patient Sample: All male patients without baseline sexual incapacity and having ALIF for lumbar spondylosis or spondylolisthesis of the lowest one or two lumbar levels with and without rhBMP-2, from 2002 through 2011., Outcome Measures: Diagnosis of RE as a new finding after ALIF compared against BMP-2 exposure, comorbid conditions, and other urological complications after ALIF surgery., Methods: From the comprehensive surgical database at a high volume, university practice, male subjects having ALIF at one (L5/S1) or two levels (L4/5, L5/S1) from 2002 to 2011 were identified. Baseline comorbid factors, postoperative urinary catheter/retention events, and RE events were recorded and comparative incidence compared., Results: There were four consecutive-patient cohorts identified: one before rhBMP-2 use was adopted (n=174), two cohorts in which BMP-2 use was routine (n=88 and n=151), and one final cohort after BMP-2 use was discontinued from routine use (n=59). The cohorts with and without BMP-2 exposure were closely comparable for age, approach, levels of surgery, comorbid factors affecting RE. Of 239 patients with ALIF and exposure to BMP-2, RE was diagnosed in 15 subjects (6.3%), compared with an RE diagnosis rate of two of 233 control patients without BMP-2 exposure (0.9%; p=.0012). Urinary retention after bladder catheter removal was also more frequently observed in patients exposed to BMP-2 (9.7%) compared with control patients (4.6%; p=.043). Of the baseline comorbid factors, medical or surgical treatment for prostatic hypertrophy disease was associated with an increased risk of RE in the BMP-2 patients (p=.034)., Conclusions: This study confirms previous reports of a higher rate of RE in ALIF procedures using rhBMP-2 and an open anterior approach to the spine. This effect may be associated with an increased risk of postoperative urinary retention after BMP-2 exposure. The magnitude of the RE effect may be increased with concomitant prostatic disease treatments., (Copyright © 2012 Elsevier Inc. All rights reserved.)

Purpose: The US Food and Drug Administration has approved recombinant human bone morphogenetic protein 2 (rhBMP-2) (Infuse Bone Graft; Medtronic Sofamor Danek, Minneapolis, MN) as an alternative to autogenous bone graft for sinus augmentations and for localized alveolar ridge augmentations for defects associated with extraction sockets. The objective of this analysis was to characterize adverse events reported after the use of rhBMP-2 in oral and maxillofacial procedures., Materials and Methods: The US Food and Drug Administration's Manufacturer and User Facility Device Experience database contains reports of adverse events involving medical devices. The publicly available version of the database was searched for reports for the brand name Infuse Bone Graft. Descriptive statistics were used to summarize the procedures and adverse events., Results: As of April 30, 2011, the Manufacturer and User Facility Device Experience database contained 83 reports of adverse events after oral and maxillofacial operations involving rhBMP-2. Of these reports, 55 (66.3%) described off-label uses, such as reconstruction of the mandible after fracture or cancer or alveolar cleft repair. The most commonly reported adverse events included local reactions, graft failure, infections, and other wound complications. Of the reports, 25 (30.1%) stated that the patient required additional surgery to address the reported adverse event., Conclusions: Serious adverse events, some of which may require a second operation, can occur after the use of rhBMP-2 in oral and maxillofacial procedures. In this analysis graft, failure and pseudarthrosis were more commonly reported after off-label uses of rhBMP-2 than approved uses., (Published by Elsevier Inc.)

Recombinant human bone morphogenetic protein-2 (rhBMP-2) is a critical regulator of osteogenic capacity that is commonly used in bone grafts. The effectiveness of rhBMP-2 may be reduced as it can become unstable and degraded after injection into the body. Microspheres are considered appropriate vehicles for the sustained release of proteins in vivo. In this study, rhBMP-2 microspheres were manufactured using the water-in-oil-in-water (W/O/W) double-emulsion solvent-extraction technique by encapsulation in poly(lactic-co-glycolic) acid (PLGA). The microspheres were then embedded in two hydrogels made of either poloxamer 407 hydrogel or chitosan thioglycolic acid (CS-TA). The encapsulation efficiency and in vitro release of rhBMP-2 were examined and compared with the control release system (rhBMP-2 microspheres alone). The rhBMP-2 microspheres in the CS-TA hydrogel showed the lowest burst release (about 40% in the first 8h) among the three groups. The mechanisms may be the high viscosity of CS-TA hydrogel and the sustained release characteristics of CS-TA itself. The CS-TA hydrogel combined with PLGA microspheres can efficiently encapsulate rhBMP-2, control the burst release at early time points, and provide sustained release in vitro. It may be an appropriate rhBMP-2 vehicle for bone regeneration.

The primary goal of treatment for postmenopausal osteoporosis is the reduction in fracture risk. Bisphosphonates have long been established as first-line therapy for osteoporosis and several of these drugs significantly reduce osteoporotic fracture risk. Alendronate, risedronate, ibandronate and zoledronic acid all provide fracture protection for patients with postmenopausal osteoporosis. All four agents have demonstrated efficacy in preventing vertebral fractures, but only zoledronic acid and risedronate significantly reduce non-vertebral fracture risk in pivotal trials. Moreover, reduction in hip fracture risk has been established for alendronate, risedronate and zoledronic acid. Ibandronate and zoledronic acid have the most persistent antifracture effect. Bisphosphonates have been associated with a number of side effects, with a well-documented association between gastrointestinal adverse events and oral administration, and between acute phase reactions and intravenous administration.

The Food and Drug Administration (FDA) indicates that bone morphogenetic protein (BMP) products are contraindicated in pediatric patients. However, it acknowledges the off-label use of BMP in difficult cases. Although the relative safety of BMP in children has been reported for lower extremity and spine procedures, little information exists for the safety of BMP used in the pediatric upper extremity. We present a case of a massive inflammatory reaction after use of recombinant human BMP-2 for repair of a symptomatic ulnar nonunion in a child. The case illustrates the potential difficulties of using the dose-dependent properties of BMP in the treatment of pediatric upper extremity nonunions when the dose calculations of BMP for children have not yet been defined., (Copyright © 2012 American Society for Surgery of the Hand. Published by Elsevier Inc. All rights reserved.)

Objectives/hypothesis: To establish the relevance of the bone morphogenetic protein (BMP) signaling pathway in human oral squamous cell carcinoma (OSCCA) cell lines and determine if there is a biologic impact of stimulating this pathway with recombinant human (rh) BMP-2., Study Design: In vitro laboratory investigations and in vivo analysis using an orthotopic animal model for oral cancer., Methods: Gene expression profiles for BMP-2 and components of the BMP-signaling pathway were determined using reverse transcriptase-polymerase chain reaction. In vivo effects were evaluated using Kaplan-Meier survival analysis and studying histopathologic changes in established tumor xenografts with or without rhBMP-2 pretreatment. A phosphokinase array was used to detect levels of activation in signaling kinases., Results: The BMP-2 gene was expressed in 90% of the 30 OSCCA cell lines tested. Gene expression of all components of the BMP-signaling pathway was highly conserved. Tumor xenografts established with rhBMP-2-treated cells showed more rapid local growth that resulted in worse animal survival as compared to the control group. These tumors had a more poorly differentiated morphology. Changes in protein kinases suggested interactions of BMP-2 signaling with the Wnt-β-catenin, and Janus kinase/signal transducers and activators of transcription (JAK/STAT) pathways., Conclusions: Human OSCCA cell lines frequently express BMP-2 and all necessary components of the BMP-signaling pathway. Exogenous treatment of human OSCCA cell lines with rhBMP-2 prior to engraftment in an orthotopic animal model caused the subsequent tumors to be more locally aggressive with worse survival. Continued caution should be used for considering rhBMP-2 for reconstruction of bone defects in oral cancer patients., (Copyright © 2011 The American Laryngological, Rhinological, and Otological Society, Inc.)

Study Design: Prospective, longitudinal cohort study., Objective: To examine the incidence of bone morphogenetic protein (BMP)-2 antibody formation in lumbar spine applications and to determine the clinical significance of an antibody response., Summary of Background Data: Immune responses can affect the safety and efficacy profile of recombinant proteins. Type, incidence, and time course of antibody formation were evaluated in clinical studies investigating recombinant human bone morphogenetic protein (rhBMP)-2 in spinal arthrodesis., Methods: Analysis of antibody formation to BMP-2, bovine collagen, and human collagen was performed after three prospective clinical studies investigating rhBMP-2 in single-level lumbar spinal arthrodesis. Two studies investigated rhBMP-2 applied to an absorbable collagen sponge at 1.5 mg/cm3 in lumbar interbody fusion (n=449); one study investigated rhBMP-2 applied to a ceramic and collagen compression-resistant matrix at 2.0 mg/cm3 in instrumented posterolateral fusion (n=239). Control patients received iliac crest bone graft (n=360). Two validated enzyme-linked immunosorbent assays were used to test for BMP-2 antibodies. Neutralizing antibodies were assessed using a cell bioassay. The incidence of antibodies to bovine and human collagen was determined. Radiographic and clinical outcome data were assessed to determine whether antibodies were correlated to patient outcomes., Results: BMP-2 antibody rates ranged from 0.8% to 6.4% in rhBMP-2 patients and from 0% to 2.3% in control patients. Formation of BMP-2 antibodies peaked within the first 3 months and returned toward baseline values by 12 months. No neutralizing antibodies were detected. Bovine collagen antibody rates ranged from 12.7% to 18.8% in the rhBMP-2 patients and from 12.9% to 21.2% in the control patients. No antibodies to human collagen were detected. Adverse event rates were similar in antibody-positive and antibody-negative patients. BMP-2 antibodies did not affect bridging bone rates., Conclusion: Formation of anti-BMP-2 antibodies was low and transient. No neutralizing antibodies were observed. Formation of antibodies did not affect fusion success or appear to have clinical sequelae.