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Background: Large calvarial defects represent a major reconstructive challenge, as they do not heal spontaneously. Infection causes inflammation and scarring, further reducing the healing capacity of the calvaria. Bone morphogenetic protein-2 (BMP2) has been shown to stimulate osteogenesis but has significant side effects in high doses. BMP2 has not been tested in combination with antiinflammatory cytokines such as interleukin-10., Methods: Sixteen New Zealand White rabbits underwent 15 × 15-mm flap calvarectomies. The flap was incubated in Staphylococcus aureus and replaced, and infection and scarring were allowed to develop. The flap was subsequently removed and the wound débrided. A 15 × 15-mm square of acellular dermal matrix biopatterned with low-dose BMP2, interleukin-10, or a combination was implanted. Computed tomographic scans were taken over 42 days. Rabbits were then killed and histology was performed., Results: Defects treated with BMP2 showed significantly (p < 0.05) greater osseous regeneration than untreated controls. Interleukin-10 did not significantly augment the healing achieved with BMP2, and interleukin-10 alone did not significantly increase healing compared with controls. Histology showed evidence of bone formation in defects treated with BMP2. Untreated controls and defects treated with interleukin-10 alone showed only fibrous tissue in the defect site., Conclusions: Low-dose BMP2 delivered directly to the scarred calvarial defect augments bony healing. Interleukin-10 at the dose applied did not significantly augment healing alone or in combination with BMP2. Healing had not finished at 42 days and analysis at later time points or the use of higher doses of BMP2 may yield greater healing. more...

Bone morphogenetic protein 2 (BMP2) bioprinted on biological matrix induces osseous regeneration in large calvarial defects in rabbits, both uncomplicated and scarred. Healing in unfavorable defects scarred from previous infection is decreased due in part to the lack of vascularity. This impedes the access of mesenchymal stem cells, key to osseous regeneration and the efficacy of BMP2, to the wound bed. The authors hypothesized that bioprinted vascular endothelial growth factor (VEGF) would augment the osseous regeneration achieved with low dose biopatterned BMP2 alone. Thirteen New Zealand white rabbits underwent subtotal calvariectomy using a dental cutting burr. Care was taken to preserve the underlying dura. A 15 mm × 15 mm flap of bone was cut away and incubated in a 1 × 108 cfu/mL planktonic solution of S aureus before reimplantation. After 2 weeks of subsequent infection the flap was removed and the surgical wound debrided followed by 10 days of antibiotic treatment. On postoperative day 42 the calvarial defects were treated with acellular dermal matrix bioprinted with nothing (control), VEGF, BMP2, BMP2/VEGF combined. Bone growth was analyzed with serial CT and postmortem histology. Defects treated with BMP2 (BMP2 alone and BMP2/VEGF combination) showed significantly greater healing than control and VEGF treated defect (P < 0.5). Vascular endothelial growth factor treated defect demonstrated less healing than control and VEGF/BMP2 combination treatments achieved less healing than BMP2 alone though these differences were nonsignificant. Low dose BMP2-patterned acellular dermal matrix improves healing of scarred calvarial defects. Vascular endothelial growth factor at the doses applied in this study failed to increase healing. more...

Background: Repair of complex cranial defects is hindered by a paucity of appropriate donor tissue. Bone morphogenetic protein 2 (BMP2) and transforming growth factor beta 1 (TGFβ1) have been shown separately to induce bone formation through physiologically distinct mechanisms and potentially improve surgical outcome for cranial defect repair by obviating the need for donor tissue. We hypothesize that a combination of BMP2 and TGFβ1 would improve calvarial defect healing by augmenting physiologic osteogenic mechanisms., Methods/results: Coronal suturectomies (3×15 mm) were performed in 10-day-old New Zealand White rabbits. DermaMatrix™ (3×15mm) patterned with four treatments (vehicle, 350 ng BMP2, 200 ng TGFβ1, or 350 ng BMP2+200 ng TGFβ1) was placed in suturectomy sites and rabbits were euthanized at 6 weeks of age. Two-dimensional (2D) defect healing, bone volume, and bone density were quantified by computed tomography. Regenerated bone was qualitatively assessed histologically. One-way analysis of variance revealed significant group main effects for all bone quantity measures. Analysis revealed significant differences in 2D defect healing, bone volume, and bone density between the control group and all treatment groups, but no significant differences were detected among the three growth factor treatment groups. Qualitatively, TGFβ1 treatment produced bone with morphology most similar to native bone. TGFβ1-regenerated bone contained a suture-like tissue, growing from the lateral edge of the defect margin toward the midline. Unique to the BMP2 treatment group, regenerated bone contained lacunae with chondrocytes, demonstrating the presence of endochondral ossification., Conclusions/significance: Total healing in BMP2 and TGFβ1 treatment groups is not significantly different. The combination of BMP2+TGFβ1 did not significantly increase bone healing compared with treatment with BMP2 or TGFβ1 alone postoperatively at 4 weeks. We highlight the potential use of TGFβ1 to regenerate calvarial bone and cranial sutures. TGFβ1 therapy significantly augmented bony defect healing at an earlier time point when compared with control, regenerated bone along the native intramembranous ossification pathway, and (unlike BMP2 alone or in combination with TGFβ1) permitted normal suture reformation. We propose a novel method of craniofacial bone regeneration using low-dose, spatially controlled growth factor therapies to minimize potentially harmful effects while maximizing local bioavailability and regenerating native tissues. more...

Recombinant human bone morphogenetic protein-2 (rhBMP-2) is gaining popularity in craniofacial applications. Calvarial defects are, under normal circumstances, subjected to only minimal levels of the biomechanical stresses known to play an important role in osteogenesis, yet regenerated calvarial bone must be capable of withstanding traumatic forces such that the underlying neurocapsule is protected. The aim of this study is to, for the first time, assess the biomechanical properties of calvarial bone regenerated with derivations of a commercially available rhBMP-2-based system. Standardized calvarial defects were created in 23 adult male canines. These defects were treated with rhBMP-2 on one of several carriers. After 24 weeks, the biomechanical properties of the rhBMP-2-generated bone were compared to those of controls with a modified punch-out test (Bluehill 2; Instron, Norwood, Mass) and compared using a paired nonparametric analyses (SPSS, 17.0, Chicago, Ill). In a previously published report, defects across all the rhBMP-2 therapy groups were observed to have a mean rate of 99.5% radio-opacity at 24 weeks indicating nearly full bony coverage of the calvarial defect (compared to 32.7% in surgical controls). For ultimate load, ultimate energy, and first peak energy, there were significant differences (P<0.05) with the control native bone having more robust biomechanical properties than the rhBMP-2-generated bone. We conclude from these findings that rhBMP-2-generated calvarial bone is significantly less protective against trauma than native bone at 6 months. Further investigation is required to assess the efficacy of rhBMP-2 in healing calvarial defects in the longer term. more...

Background: Recombinant human bone morphogenetic protein-2 (rhBMP-2) delivered on an absorbable collagen sponge is a U.S. Food and Drug Administration-approved therapy shown to be an effective means of generating bone formation in multiple clinical settings. However, the optimum dose and delivery of rhBMP-2 to the calvaria are undetermined. The aim of the authors' study was to investigate the use of rhBMP-2 in addressing calvarial defects in a large-animal model through a variety of modifications to this U.S. Food and Drug Administration-approved therapy., Methods: Twenty-three adult canines underwent the creation of a standard calvarial defect and received either no treatment, 0.2 mg/ml rhBMP-2 in an absorbable collagen sponge, 0.2 mg/ml rhBMP-2 in an absorbable collagen sponge with corticocancellous chips, 0.2 mg/ml rhBMP-2 in an absorbable collagen sponge with MasterGraft Granules, or 0.4 mg/ml rhBMP-2 in a compression-resistant matrix carrier. Direct comparisons of defect radiopacity were performed at 0, 8, 16, and 24 weeks postoperatively before the animals were euthanized. All specimens were evaluated qualitatively with histology., Results: Surgical control animals had an average defect radiopacity of 32.7 percent at study completion compared with an average of 99.95 percent across all treatment groups. Ectopic bone formation was found consistently in all treatment groups with varying degrees of severity. Regenerated bone thickness, compactness, and organization varied qualitatively between groups., Conclusions: Treatment with 0.2 mg/ml rhBMP-2 in an absorbable collagen sponge with MasterGraft Granules showed the least amount of ectopic bone formation and the most compact bone formation within the defect, and produced reasonably consistent bony thickness across the defect. Future studies should focus on spatial regulation of rhBMP-2 to minimize unwanted bone formation. more...

Objective: To evaluate postoperative pain, hospital length of stay (LOS), and associated costs of multiple perioperative analgesic strategies following alveolar bone grafting (ABG). Design: Retrospective comparative cohort study. Setting: Tertiary care pediatric hospital. Patients/Participants: Iliac crest bone graft (ICBG) harvest techniques: "Open Harvest" (n = 22), "Trephine Only" (n = 14), or "Trephine + Pain Pump" (n = 25). Intervention: The "Open Harvest" group underwent open ICBG harvest with 3-walled osteotomies. For the other 2 treatment groups, a trephine drill was used to harvest iliac crest bone with a ropivacaine infusion pump into the hip donor site ("Trephine + Pain Pump") or without ("Trephine Only"). Patients who underwent ABG with only cadaveric allograft were analyzed as a comparison group ("No Harvest"). Main Outcomes Measures: Outcomes were planned prior to data collection: maximum pain score, hospital LOS, and associated health care costs. Results: Maximum pain scores were significantly higher in the "Open Harvest" group (7.3/10) compared to "Trephine + Pain Pump" (1.8/10; P < .0001) and "No Harvest" groups (2.8/10; P < .01). Hospital LOS decreased from 2.4 days ("Open Harvest") to 0.5 days (Trephine + Pain Pump"; P < .0001). Twelve (48%) patients from "Trephine + Pain Pump" were discharged on the day of surgery. The "Trephine + Pain Pump" saved an estimated $5336 for a unilateral ABG and $7265 for a bilateral ABG compared to "Open Harvest." Conclusions: The combined use of the trephine ICBG technique and ropivacaine infusion catheter effectively decreased pain, shortened hospital stay, and improved cost saving compared to patients who have undergone other methods of ICBG. [ABSTRACT FROM AUTHOR] more...