Clinical application of injectable calcium sulfate on early bony consolidation in distraction osteogenesis for the treatment of craniofacial microsomia

Application of calcium sulfate as graft material in implantology and maxillofacial procedures: A review of literature

Calcium sulphate (plaster of Paris) has been used since 1892 to fill bone defects and as a good bone graft substitute. Calcium sulphate is an osteoconductive, inorganic substance. Following 75 years, many other authors reported variable and a better result in grafting of bone defects and in several cases of immediate and delayed dental implants for good osseointegrations, with no complications attributed to the calcium sulphate. Early results were variable, because of its conflicting crystalline structure, purity, and quality of the calcium sulphate. Apart from this, calcium sulphate also shows predictable resorption rate in vivo, presence of minimal trace elements and extremely uniform crystalline structure. Calcium sulphate is a bio-inert material and get resorbed over a period of weeks and fibrovascular tissue takes its place which eventually allows neovascularization and bone formation within the area. Use During the conventional surgical treatment addition of calcium sulphate as a bone graft of in case of placement of dental implants and pathological bony defects it improves the clinical outcome. Calcium sulphate also act as a barrier and filling material for the treatment of "through and through" bony lesions. Use of calcium sulphate as a bone graft substitute avoids the complications and morbidity associated with autograft like infection, second surgery.

Application of chemical factors for acceleration of consolidation phase of the distraction osteogenesis: a scoping review

PURPOSE

This study aimed to analyze the effect of injecting chemical factors compared to conventional distraction osteogenesis (DO) treatment on the bone formation of the distracted area of the maxillofacial region in human and animal studies.

METHOD

Electronic search was done in PubMed, Scopus, Embase, and Cochrane database for studies published until September 2021. The studies' risk of bias (ROB) was assessed using the Cochrane Collaborations and NIH quality assessment tools. Meta-analyses were performed to assess the difference in the amount of bone formation and maximal load tolerance.

RESULTS

Among a total of 58 included studies, eight studies analyzed the bone formation rate of the distracted area in human models and others in animal models. Results of the human studies showed acceptable outcomes in the case of using bone morphogenic protein-2 (BMP-2), autologous bone-platelet gel, and calcium sulfate. However, using platelet reach plasma does not increase the rate of bone formation significantly. Quantitative analyses showed that both BMP-2 (SMD = 26.57; 95% CI = 18.86 to 34.28) and neuron growth factor (NGF) (SMD = 16.19; 95% CI = 9.64 to 22.75) increase the amount of bone formation. Besides, NGF increased the amount of load tolerance significantly (SMD = 30.03; 95% CI = 19.91 to 40.16). Additionally, BMP-2 has no significant impact on the post-treatment maxillary length (SMD = 9.19; 95% CI =  - 2.35 to 20.73).

CONCLUSION

Limited number of human studies with low quality used chemical factors to enhance osteogenesis and showed acceptable results. However, more studies with higher quality are required.

A carboxymethyl cellulose bone graft carrier delays early bone healing in an ovine model

A limitation in the use of calcium phosphate (CaP) is that in its raw form, it comprises blocks or granules, which are limited in their utility for orthopedic surgery and a number of commercial bone grafts are supplied within an aqueous based carboxymethyl cellulose (CMC) putty. Our hypothesis was that CMC combined with a porous silicate-substituted CaP (SiCaP) scaffold would have no negative effect on bone formation after implantation in an ovine femoral condyle. Defects were either (a) empty or filled with (b) SiCaP granules, (c) CMC-SiCaP Putty or (d) a SiCaP press-fit dry block. Scaffolds were identical in composition and remained in vivo for 4, 8, and 12 weeks. Bone apposition rates, bone area, percentage of bone-implant contact and graft area were quantified. At 4 and 8 weeks, significantly more new bone and percentage of bone-implant contact was measured within granules when compared with both putty and block scaffolds. At 12 weeks, significantly increased bone was measured for the granules when compared with blocks and no significant difference was found when the granules and putty scaffolds were compared. Results showed the disadvantageous effect that CMC may have on early bone growth and that granules increased new bone formation when compared with a press-fit block composed of the same material.

Calcium-containing scaffolds induce bone regeneration by regulating mesenchymal stem cell differentiation and migration

Background

Osteoinduction and subsequent bone formation rely on efficient mesenchymal stem cell (MSC) recruitment. It is also known that migration is induced by gradients of growth factors and cytokines. Degradation of Ca²⁺-containing biomaterials mimics the bone remodeling compartment producing a localized calcium-rich osteoinductive microenvironment. The aim of our study was to determine the effect of calcium sulfate (CaSO₄) on MSC migration. In addition, to evaluate the influence of CaSO₄ on MSC differentiation and the potential molecular mechanisms involved.

Methods

A circular calvarial bone defect (5 mm diameter) was created in the parietal bone of 35 Balb-C mice. We prepared and implanted a cell-free agarose/gelatin scaffold alone or in combination with different CaSO₄ concentrations into the bone defects. After 7 weeks, we determined the new bone regenerated by micro-CT and histological analysis. In vitro, we evaluated the CaSO₄ effects on MSC migration by both wound healing and agarose spot assays. Osteoblastic gene expression after BMP-2 and CaSO₄ treatment was also evaluated by qPCR.

Results

CaSO₄ increased MSC migration and bone formation in a concentration-dependent manner. Micro-CT analysis showed that the addition of CaSO₄ significantly enhanced bone regeneration compared to the scaffold alone. The histological evaluation confirmed an increased number of endogenous cells recruited into the cell-free CaSO₄-containing scaffolds. Furthermore, MSC migration in vitro and active AKT levels were attenuated when CaSO₄ and BMP-2 were in combination. Addition of LY294002 and Wortmannin abrogated the CaSO₄ effects on MSC migration.

Conclusions

Specific CaSO₄ concentrations induce bone regeneration of calvarial defects in part by acting on the host’s undifferentiated MSCs and promoting their migration. Progenitor cell recruitment is followed by a gradual increment in osteoblast gene expression. Moreover, CaSO₄ regulates BMP-2-induced MSC migration by differentially activating the PI3K/AKT pathway. Altogether, these results suggest that CaSO₄ scaffolds could have potential applications for bone regeneration.

Electronic supplementary material

The online version of this article (doi:10.1186/s13287-017-0713-0) contains supplementary material, which is available to authorized users.

Comparable bone healing capacity of different bone graft matrices in a rabbit segmental defect model

We compared the bone healing capacity of three different demineralized bone matrix (DBM) products applied using different carrier molecules (hyaluronic acid [HA] vs. carboxymethylcellulose [CMC]) or bone compositions (cortical bone vs. cortical bone and cancellous bone) in a rabbit segmental defect model. Overall, 15-mm segmental defects in the left and right radiuses were created in 36 New Zealand White rabbits and filled with HA-based demineralized cortical bone matrix (DBX), CMC-based demineralized cortical bone matrix (DB) or CMC-based demineralized cortical bone with cancellous bone (NDDB), and the wound area was evaluated at 4, 8, and 12 weeks post-implantation. DBX showed significantly lower radiopacity, bone volume fraction, and bone mineral density than DB and NDDB before implantation. However, bone healing score, bone volume fraction, bone mineral density, and residual bone area at 4, 8, and 12 weeks post-implantation revealed no significant differences in bone healing capacity. Overall, three DBM products with different carrier molecules or bone compositions showed similar bone healing capacity.

Integration of a novel injectable nano calcium sulfate/alginate scaffold and BMP2 gene-modified mesenchymal stem cells for bone regeneration

The repair of craniofacial bone defects is surgically challenging due to the complex anatomical structure of the craniofacial skeleton. Current strategies for bone tissue engineering using a preformed scaffold have not resulted in the expected clinical regeneration due to difficulty in seeding cells into the deep internal space of scaffold, and the inability to inject them in minimally invasive surgeries. In this study, we used the osteoconductive and mechanical properties of nano-scale calcium sulfate (nCS) and the biocompatibility of alginate to develop the injectable nCS/alginate (nCS/A) paste, and characterized the effect of this nCS/A paste loaded with bone morphogenetic protein 2 (BMP2) gene-modified rat mesenchymal stem cells (MSCs) on bone and blood vessel growth. Our results showed that the nCS/A paste was injectable under small injection forces. The mechanical properties of the nCS/A paste were increased with an increased proportion of alginate. MSCs maintained their viability after the injection, and MSCs and BMP2 gene-modified MSCs in the injectable pastes remained viable, osteodifferentiated, and yielded high alkaline phosphatase activity. By testing the ability of this injectable paste and BMP2-gene-modified MSCs for the repair of critical-sized calvarial bone defects in a rat model, we found that BMP2-gene-modified MSCs in nCS/A (nCS/A+M/B2) showed robust osteogenic activity, which resulted in consistent bone bridging of the bone defects. The vessel density in nCS/A+M/B2 was significantly higher than that in the groups of blank control, nCS/A alone, and nCS/A mixed with MSCs (nCS/A+M). These results indicate that BMP2 promotes MSCs-mediated bone formation and vascularization in nCS/A paste. Overall, the results demonstrated that the combination of injectable nCS/A paste and BMP2-gene-modified MSCs is a new and effective strategy for the repair of bone defects.

Calcium phosphate combination biomaterials as human mesenchymal stem cell delivery vehicles for bone repair

A new class of biomimetic, bioresorbable apatitic calcium phosphate cement (CPC) was recently developed. The handling characteristics, and the ability to harden at body temperature in the presence of physiological saline, make this material an attractive clinical bone substitute and delivery vehicle for therapeutic agents in orthopedic applications. The major challenge with the material is formulating an injectable paste with options for cell delivery, in order to regenerate new bone faster and with high quality. In this study, three different additives and/or viscosity modifiers (carboxymethylcellulose, silk, and alginate) were incorporated into a CPC matrix. Injectability, cell viability, cell proliferation, surface morphology, and gene expression for osteogenesis of hMSCs were all evaluated. Injectable CPC-gel composites with cell protection were achieved. The CPC modified with alginate provided the best results based on cell proliferation, ALP and collagen production, and osteogenic transcript increases (for ALP, type I collagen, BSP, and OP). Furthermore, osteogenic analysis indicated lineage-specific differentiation of hMSCs into osteogenic outcomes. The results suggest that CPC mixed with alginate can be used as a cell delivery vehicle for bone regeneration.

Extracorporeal shock wave accelerates consolidation in distraction osteogenesis of the rat mandible

BACKGROUND

One of major limitations of applying distraction osteogenesis for craniofacial skeleton hypoplasia is the long duration for bony consolidation. This study investigated whether extracorporeal shock wave therapy (ESWT) could accelerate bony consolidation in distraction osteogenesis of the rat mandible.

METHODS AND MATERIALS

An L-shape osteotomy was performed unilaterally in the hemimandible of Sprague-Dawley rats. An internal distracter was employed to create a 7-mm distraction gap in the mandible. One hundred twenty rats were divided into three groups. The distraction zone of the mandible was received no treatment as controls (group I). Group II received ESWT (500 impulses at 14 kV) at 2 weeks postoperatively. Group III treated with 500 ESW impulses at 21 kV at 2 weeks postoperatively.

RESULTS

Dual-energy X-ray absorptiometry and material testing showed that optimal dosage of ESWT in group II significantly increased mineral density and enhanced biomechanical strength of the bone tissue. In histomorphological analysis, the mandibular tissue in group II showed intense osteoblastic cell recruitment, new bone formation, and vascularization. The osteoblasts in the distracted zone in group II indicated significantly strong immunoreactivities for proliferating cell nuclear antigen, vascular endothelial growth factor, and bone morphogenetic protein-2, when compared with other groups.

CONCLUSION

Optimal dosage of ESWT was beneficial for accelerating facial skeleton consolidation and bone regeneration in the distracted rat mandible tissue. The mechanism was presumably associated with the up-regulation of neovascularization, cell proliferation, and osteogenic growth factor expression in bone microenvironment.

Effects of chitosan-coated pressed calcium sulfate pellets combined with recombinant human bone morphogenetic protein 2 on bone formation in femoral condyle-contained bone defects

Calcium sulfate has a rapid degradation rate and little osteoinductive capability. Chitosan-coated pressed calcium sulfate pellets combined with recombinant human bone morphogenetic protein 2 (rhBMP-2) have been developed that exhibit decreased resorption speed and increased compressive strength and osteoinduction. A rabbit femoral condyle-contained bone defect model was used to study the restoration of the defects treated with chitosan-coated pressed calcium sulfate pellets combined with rhBMP-2, chitosan-coated pressed calcium sulfate pellets, and uncoated pressed calcium sulfate pellets. No pellets were implanted in the control group. After 3 and 13 weeks, the results indicated that chitosan-coated pressed calcium sulfate pellets exhibited relatively slower resorption that closely coincides with the growth rate of new bone and enhanced osteogenesis when combined with rhBMP-2.

Augmentation of pedicle screw fixation strength using an injectable calcium sulfate cement: an in vivo study

STUDY DESIGN

An in vivo landrace model of cement augmentation of pedicle screw was established, and axial pull-out tests and histological analysis were performed.

OBJECTIVE

To investigate the long-term in vivo biomechanical performance of pedicle screws augmented with calcium sulfate cement.

SUMMARY OF BACKGROUND DATA

Little information is available on the long-term biomechanical performance of pedicle screws augmented with calcium sulfate cement in vivo.

METHODS

Ten pedicle screws were implanted into the lumbar vertebrae of 15 adult females landraces weighing 105 to 115 kg. The pedicle screws were augmented with Polymethyl methacrylate (PMMA), augmented with the calcium sulfate cement, or not augmented. The landraces were randomized into 3 study periods of day 1, 6 weeks, and 12 weeks. At the end of the assigned study periods, the animals were killed and axial pull-out tests and histological analyses were conducted on the isolated specimen vertebrae.

RESULTS

No significant difference was found among the 1-day, 6-week,and 12-week control group (P > 0.18), no significant difference was found among the 1-day, 6-week and 12-week PMMA group (P > 0.59), and no significant difference was found among the 1-day, 6-week and 12-week calcium sulfate group (P > 0.27). The maximum POS of the PMMA groups was significantly greater than that of the calcium sulfate groups (P < 0.002), the maximum POS of the calcium sulfate groups was significantly greater than that of the control groups (P < 0.004). Histologically progressive absorption of the calcium sulfate was evident. The bone walls around the screws in the 12-week calcium sulfate group were statistically significantly thicker than that of the 12-week control group and that of the 12-week PMMA group.

CONCLUSION

Results of this study demonstrate that the injectable calcium sulfate cement can significantly improve the immediate POS of pedicle screw fixation, and this effect can be maintained even if the calcium sulfate cement has been absorbed completely, which may result from that the calcium sulfate cement resorption paralleled bone ingrowth.

Effects of chitosan-coated pressed calcium sulfate pellet combined with recombinant human bone morphogenetic protein 2 on restoration of segmental bone defect

A chitosan-coated pressed calcium sulfate pellet combined with recombinant human bone morphogenetic protein 2 (rhBMP-2) has been developed with increased compressive strength and osteoinduction, but with a resorption profile only slightly slower than uncoated pellet. A radial segmental defect model of rabbit was used to study the restoration effect on defect treated with chitosan-coated pressed calcium sulfate pellet combined with rhBMP-2, coated pressed calcium sulfate pellet, and uncoated pressed calcium sulfate pellet. Nothing was implanted in the control group. After 4, 8, and 12 weeks, the results indicated that coated pressed calcium sulfate pellet combined with rhBMP-2 and coated pressed calcium sulfate pellet facilitated new bone formation on defected bone and that particularly the former was more effective than the latter.

Meta-analysis of mandibular distraction osteogenesis: clinical applications and functional outcomes

BACKGROUND

Mandibular distraction osteogenesis has been used effectively to treat syndromic craniofacial deformities. In recent years, its scope of application has widened to include treatment of airway obstruction in adults and children and nonsyndromic class II mandibular hypoplasia. So far, there has been no evidence-based review of mandibular distraction osteogenesis for mandibular lengthening.

METHODS

Two rounds of searches were performed by two independent assessors. The first-round PubMed search used the keywords "mandible" and "distraction osteogenesis." In the second-round search, the reference lists of the articles were retrieved. For both rounds, abstracts and then full articles were reviewed and selected on the basis of a set of inclusion and exclusion criteria.

RESULTS

The 178 retrieved articles yielded 1185 mandibular distraction osteogenesis patients: 539 received unilateral mandibular distraction osteogenesis and 646 received bilateral mandibular distraction osteogenesis. Mandibular distraction osteogenesis was reported to improve facial asymmetry and retrognathia (50.1 percent), correct the slanted lip commissure (24.7 percent), and improve or level the mandibular occlusal plane (11.1 percent) in unilateral asymmetry cases, whereas bilateral mandibular distraction osteogenesis was shown to be effective in preventing tracheostomies for 91.3 percent of neonates or infants with respiratory distress, and in relieving symptoms of obstructive sleep apnea for 97.0 percent of children and 100 percent of adult patients.

CONCLUSIONS

Mandibular distraction osteogenesis is effective in treating craniofacial deformities, but further clinical trials are required to assess the long-term stability and to compare the treatment with conventional treatment methods, especially in cases of obstructive sleep apnea or class II mandibular hypoplasia.

Calcium sulfate–carboxymethylcellulose bone graft binder: Histologic and morphometric evaluation in a critical size defect

Calcium sulfate (CS) is widely used as a bone graft binder and expander. Recent reports indicate that carboxymethylcellulose (CMC) can improve the clinical properties of CS when used as binder for particulate bone grafts; however, limited information is available on the effects of CMC on bone regeneration. The purpose of this study was to evaluate the histologic and morphometric characteristics of bone formation in calvarial defects grafted with a CS-based putty containing 10% CMC in combination with allogeneic demineralized bone matrix (DBM). Bone formation and graft/binder resorption were compared with a surgical grade CS and DBM in paired critical-sized calvarial defects in 25 Wistar rats (350-450 g). Six animals each provided paired defects at 7, 14, 21, and 28 days postsurgery for nondecalcified processing and microscopic analysis. Defects grafted with CS or CS-CMC putty as the DBM binder exhibited similar patterns and proportions of bone formation, fibrous tissue/marrow, and residual DBM particles. Comparable mean +/- SD proportions of new bone formation (31.7 +/- 9.5 and 33.7 +/- 12.9), fibrous tissue/marrow (54.2 +/- 8.3 and 53.0 +/- 10.8), residual DBM particles (8.3 +/- 6.8 and 10.1 +/- 6.3), and residual binder material (5.5 +/- 4.6 and 3.7 +/- 3.5) were found at 28 days for defects grafted with CS and CS-CMC putty, respectively. Thus, CMC was found to improve the handling characteristics of CS and, when used in conjunction with DBM, supported comparable levels bone formation and patterns of binder/scaffold resorption as CS and DBM in a calvarial defect model.

Effect of Calcium Sulfate-Chitosan Composite: Pellet on Bone Formation in Bone Defect

The purpose of this experiment was to study the effects of chitosan, calcium sulfate, and calcium sulfate-chitosan composite pellet on the osteogenesis of defective tibia in rabbits. Eighty New Zealand white rabbits, each weighing approximately 3 to 3.5 kg, were used for this study. A 1-cm ostectomy was made on the middle of the tibia of each rabbit with the periosteum preserved. Nothing was implanted in the control group (group 1), and five chitosan pellets (60 mg/pellet) were implanted in group 1, three OsteoSet pellets (100 mg/pellet) in group 3, and four calcium sulfate-chitosan composite pellets (1 pellet, 80 mg; calcium sulfate 40 mg/pellet, chitosan 40 mg/pellet) in group 4. For each group, a radiographic study, bone mineral density test, three-point bending test, and histologic examination were performed in the second, fourth, and sixth weeks. In the radiologic study, in group 1, cortical bone was not formed even at 6 weeks. In group 2, it was observed at 6 weeks. In groups 3 and 4, cortical bone was partially seen around the fourth week. At 6 weeks, it was clearly observed on both sides, and the projection of the marrow cavity became distinctive, so bone consolidation was considered to be much progressed. The bone mineral density test and three-point bending test results appeared to be highly similar in groups 3 and 4 and in groups 2 and 1. Particularly at 6 weeks, the measures for groups 3 and 4 were statistically significant compared with those for groups 1 and 2 (P < 0.05). In histologic examination, new bone formation began to be seen at 2 weeks in all groups, but it was more active and faster in groups 3 and 4. At 6 weeks, fibrous connective tissue still remained at the center in groups 1 and 2; however, the fibrous connective tissue at the center was replaced with callus, the bony bridge was obvious, and lamellation of callus was observed more in groups 3 and 4. The results indicate that chitosan pellets, OsteoSet, and chitosan-calcium sulfate composite pellets facilitate new bone formation on defected bone, and that particularly OsteoSet and chitosan-calcium sulfate composite pellets are more effective than chitosan.

New developments in pediatric plastic surgery research

Pediatric plastic surgery research is a rapidly expanding field. Unique in many ways, researchers in this field stand at the union of multiple scientific specialties, including biomedical engineering, tissue engineering, polymer science, molecular biology, developmental biology, and genetics. The goal of this scientific effort is to translate research advances into improved treatments for children with congenital and acquired defects. Although the last decade has seen a dramatic acceleration in research related to pediatric plastic surgery, the next 10 years will no doubt lead to novel treatment strategies with improved clinical outcomes.

Update on craniofacial surgery

Over the course of the past year, many interesting aspects of the multidisciplinary approach to the treatment of craniofacial disorders have been furthered. Several authors have shared their experiences, and new innovations have been described. Traditional ideas with regard to bone healing and growth have been expanded upon, and the role of alloplasts also is better understood now. Diagnosis and treatment planning have come a long way with the advent of new imaging techniques and applications. The ongoing discussion regarding absorbable fixation devices has continued, and the development of new technology has been presented. Some new techniques have also been brought to the forefront. Of note, distraction osteogenesis has been embraced as a viable alternative to traditional maxillomandibular surgery with bone grafting as well as other morbid procedures.