El Gendler

Cranioplasty in the growing canine skull using demineralized perforated bone

This study was designed to test the hypothesis that demineralized perforated bone matrix implant from canine skull and tibia induces new bone formation within the calvarial defect comparable with the bone induced by autogenous graft. We also were interested in determining whether demineralized perforated bone matrix implants from membranous bone have greater osseoinductive capacity in the calvarial area than demineralized perforated bone matrix implants from endochondral bone. Forty 12-week-old purebred beagles were used. Group I consisted of animals with unrepaired surgically created calvarial defects healed by secondary intention (n = 10). Group II consisted of animals with surgically created calvarial defects in which the bone was removed and replaced with an autograft (n = 10). Group III consisted of animals with surgically created calvarial defects in which the bony defect was closed with a demineralized perforated bone matrix implant obtained from beagle calvaria (n = 10). Group IV consisted of animals with surgically created calvarial defects in which the bony defect was closed with a demineralized perforated bone matrix implant obtained from beagle tibia (n = 10). The two control groups (I and II) allowed us to isolate the inductive capacity of demineralized perforated bone matrix implants and compare it with the healing of the bone defects left unrepaired or repaired with calvarial autografts. Animals were sacrificed after 8 and 12 weeks. In the present study we were able to verify that demineralized perforated bone matrix implants are well accepted in the calvarial defects with little tissue reaction and remarkably little osteoclastic activity. In arguing for the osseoinductive potential of demineralized perforated bone, we must realize that it is likely that much of the bone consists of demineralized implant that has been invaded by host cells along with new bone in the area of the implant. This study revealed no statistically significant differences between new bone formation following the insertion of demineralized perforated bone matrix implants of the tibia or calvarium. (Plast. Reconstr. Surg. 96: 770, 1995.)

Long-term outcome of extensive skull reconstruction using demineralized perforated bone in Siamese twins joined at the skull vertex.

The successful use of cortical demineralized perforated bone in the treatment of extensive skeletal defects in children is exemplified by this case involving Siamese twins joined at the skull vertex. Four years following extensive skull reconstruction using demineralized perforated bone, an examination revealed successful calvarial reconstruction in one twin. The other twin required additional implants of demineralized perforated bone to fill in defects. However, a histologic examination taken following this additional procedure revealed that these implants neither caused tissue reaction over a 4-year period, nor showed signs of resorption. Bony remodeling and new bone formation were in progress. Compared with other bone substitutes, demineralized perforated bone has proven to be effective in the treatment of large skull defects in children.

Recombinant Human BMP-2 Enhances the Effects of Materials Used for Reconstruction of Large Cranial Defects

PURPOSE Cranial defect reconstruction presents 2 challenges: induction of new bone formation, and providing structural support during the healing process. This study compares quantity and quality of new bone formation based on various materials and support frameworks. MATERIALS AND METHODS Eighteen dogs underwent surgical removal of a significant portion of their cranial vault. Demineralized bone matrix was used to fill the defect in all animals. In 9 dogs, recombinant human bone morphogenetic protein-2 (rhBMP-2) was added, while the other 9 served as the non-rhBMP-2 group. In each group, 3 animals were fixed with cobalt chrome plates, 3 with adding platelet-rich plasma, and 3 fixed with a Lactosorb (Walter Lorenz Surgical, Inc, Jacksonville, FL) resorbable mesh. Necropsy was done at 12 weeks postoperative. Histomorphometry, density, and mechanical properties of the regenerate were analyzed. RESULTS The non-rhBMP-2 groups showed minimal substitution of demineralized bone matrix with new bone, while only sporadic remnants of demineralized bone matrix were present in the rhBMP-2 groups. The defect showed more new bone formation (P < .001) and density (P < .001) in the rhBMP-2 groups by Kruskal-Wallis test. The area of new bone was not significantly different among the rhBMP-2 subgroups. The resorbable mesh struts showed no sign of bone invasion or substitution. In the non-rhBMP-2 resorbable mesh group, demineralized bone matrix almost totally disintegrated without replacement by new bone. CONCLUSIONS The addition of rhBMP-2 to demineralized bone matrix accelerated new bone formation in large cranial defects, regardless of the supporting framework or the addition of platelet-rich plasma. The use of a resorbable mesh in such defects is advisable only if rhBMP-2 is added.

Bone generation in the reconstruction of a critical size calvarial defect in an experimental model.

This study was designed to investigate the optimal combination of known osteogenic biomaterials with shape conforming struts to achieve calvarial vault reconstruction, using a canine model. Eighteen adolescent beagles were divided equally into 6 groups. A critical-size defect of 6 x 2 cm traversed the sagittal suture. The biomaterials used for calvarial reconstruction were demineralized perforated bone matrix (DBM), recombinant human bone morphogenetic protein 2 (rhBMP2), and autogenous platelet-rich plasma (PRP). The struts used were cobalt chrome (metal) or resorbable plate. The groupings were as follows: 1) DBM + metal, 2) DBM + PRP + metal, 3) DBM + PRP + resorbable plate, 4) DBM + rhBMP2 + metal, 5) DBM + rhBMP2 + PRP + metal, and 6) DBM + rhBMP2 + resorbable plate. Animals were killed at 3 months after surgery. There was no mortality or major complications. Analysis was performed macroscopically and histologically and with computed tomography. There was complete bony regeneration in the rhBMP2 groups only. Non-rhBMP2 groups had minimal bony ingrowth from the defect edges and on the dural surface, a finding confirmed by computed tomographic scan and histology. Platelet-rich plasma did not enhance bone regeneration. Shape conformation was good with both metal and resorbable plate. rhBMP2, but not PRP, accelerated calvarial regeneration in 3 months. The DBMs in the rhBMP2 groups were substituted by new trabecular bone. Shape molding was good with both metal and resorbable plate.This study was designed to investigate the optimal combination of known osteogenic biomaterials with shape conforming struts to achieve calvarial vault reconstruction, using a canine model. Eighteen adolescent beagles were divided equally into 6 groups. A critical-size defect of 6 × 2 cm traversed the sagittal suture. The biomaterials used for calvarial reconstruction were demineralized perforated bone matrix (DBM), recombinant human bone morphogenetic protein 2 (rhBMP2), and autogenous platelet-rich plasma (PRP). The struts used were cobalt chrome (metal) or resorbable plate. The groupings were as follows: 1) DBM + metal, 2) DBM + PRP + metal, 3) DBM + PRP + resorbable plate, 4) DBM + rhBMP2 + metal, 5) DBM + rhBMP2 + PRP + metal, and 6) DBM + rhBMP2 + resorbable plate. Animals were killed at 3 months after surgery. There was no mortality or major complications. Analysis was performed macroscopically and histologically and with computed tomography. There was complete bony regeneration in the rhBMP2 groups only. Non-rhBMP2 groups had minimal bony ingrowth from the defect edges and on the dural surface, a finding confirmed by computed tomographic scan and histology. Platelet-rich plasma did not enhance bone regeneration. Shape conformation was good with both metal and resorbable plate. rhBMP2, but not PRP, accelerated calvarial regeneration in 3 months. The DBMs in the rhBMP2 groups were substituted by new trabecular bone. Shape molding was good with both metal and resorbable plate.

Demineralized bone bandeau in a patient with kleeblattschädel skull deformity

Management of complex craniofacial deformities in the neonatal setting can pose daunting reconstructive challenges due to the limited supply of autogenous bone. We present a patient who was born with idiopathic nonsyndromal pansynostosis and the associated kleeblattschädel skull deformity. In this setting the patients initial evaluation was suggestive of raised intracranial pressure and, as such, an emergent decompression was required. The native bone was unsuitable for reconstruction. Therefore, an allogenic demineralized perforated cortical iliac bone graft was used as the cornerstone of the reconstruction. Subsequent 2-year follow-up utilizing both clinical and microscopic evaluation revealed excellent osseous integration of the demineralized bone implant with near-total transformation into living bone. This clinical success has encouraged us to increase our utilization of this bone substitute in the neonatal setting.

Use of Perforated Bone Matrix for Osteoinduction and Stimulation of Bone Regeneration

It has been previously shown (1–4) that implantation of demineraiized allogenic bone matrix into non-skeletal tissue produces activation of mesenchymal cells which subsequently differentiate into chondrogenic and osteogenic cells producing cartilage and bone tissue on the site of implantation.