Complications with PMMA compared with other materials used in cranioplasty: a systematic review and meta-analysis

Abstract Polymethyl methacrylate (PMMA) has been considered a suitable material for cranioplasty. However, no consensus has been reached concerning the best material for cranioplasty with regard to minimizing complications. Thus, this systematic review and meta-analysis aimed to compare the complication rates of PMMA with those of autologous bone and titanium mesh. This review was registered with PROSPERO (CRD42016042725). Systematic searches were conducted on PubMed/MEDLINE, Scopus, and Web of Science. The focus question was, "Do PMMA prostheses used in cranioplasty have complications rates similar to those of autologous bone and titanium mesh?" A meta-analysis of complication rates was performed on the basis of dichotomous outcomes assessed by risk ratio (RR) with corresponding 95% confidence intervals (CI). From 1014 data sources, 11 articles were selected according to eligibility criteria. These articles involved 1,256 individuals and 1,278 cranioplasties using autologous bone (n = 408), PMMA (n = 379), or titanium (n = 151). The follow-up period ranged from 63 days to 54.3 months. No difference was observed between the complication rates of PMMA and autologous bone (p = 0.94; RR, 0.98; 95%CI, 0.54-1.75) or between PMMA and titanium (p = 0.38; RR, 1.59; 95%CI, 0.57-4.48). Sub-analysis of the reasons for craniotomy (trauma/non-trauma) was conducted, which revealed no significant difference (p = 0.91; RR, 0.95; 95%CI, 0.37-2.42). The meta-analysis indicated that the use of PMMA yields complication rates that are near those of autologous bone and titanium mesh.

Negative Effect of Rapidly Resorbing Properties of Bioactive Glass-Ceramics as Bone Graft Substitute in a Rabbit Lumbar Fusion Model

BACKGROUND: Bioactive glass-ceramics have the ability to directly bind to bones and have been widely used as bone graft substitutes due to their high osteoconductivity and biocompatibility. CaO-SiO2-P2O5-B2O3 glass-ceramics are known to have good osteoconductivity and are used as bone graft extenders. METHODS: This study aimed to evaluate the effects of the resorbing properties of glass-ceramics in bone fusion after producing and analyzing three types of CaO-SiO2-P2O5-B2O3 glass-ceramics with high osteoconductivity that had enhanced resorption by having an increased B2O3 content. The three types of CaO-SiO2-P2O5-B2O3 glass-ceramics with B2O3 contents of 8.0, 9.0, and 9.5 weight % were designated and grouped as P20B80, P10B90, and P5B95, respectively. Glass-ceramic types were tested for fusion rates and bone formation by employing the lumbar 5-6 intertransverse process fusion model in 51 New Zealand male rabbits. Bioactivity was assessed by soaking in simulated body fluid (SBF). RESULTS: In vitro study results showed sufficient hydroxycarbonate apatite layer formation occurred for P20B80 in1 day, for P10B90 in 3 days, and for P5B95 in 5 days after soaking in SBF. For the rabbit lumbar spine posterolateral fusion model, the autograft group recorded a 100% fusion rate with levels significantly higher than those of P20B80 (29.4%), P10B90 (0%), and P5B95 (14.3%), with high resorbing properties. Resorbing property differences among the three glass-ceramic groups were not significant. Histological results showed new bone formation confirming osteoconductivity in all three types of glass-ceramics. Radiomorphometric results also confirmed the resorbing properties of the three glass-ceramic types. CONCLUSIONS: The high resorbing properties and osteoconductivity of porous glass-ceramics can be advantageous as no glass-ceramics remain in the body. However, their relatively fast rate of resorption in the body negatively affects their role as an osteoconductive scaffold as glass-ceramics are resorbed before bony fusion.

Percutaneous Vertebroplasty Using Fresh Frozen Allogeneic Bone Chips as Filler

BACKGROUND: Vertebroplasty is not free from cement related complications. If an allograft is used as a filler, most of them can be averted. METHODS: Forty consecutive cases of osteoporotic vertebral fracture were divided into two groups by self-selection. The study and the control groups underwent vertebroplasty with fresh frozen allogeneic bone chips and bone cement, respectively. Clinical results were assessed at preoperation, postoperative day 1 and months 3, 6, and 12 by 10-grade visual analog scale (VAS), and radiological results were assessed at the same time by vertebral kyphotic angle (VKA) and local kyphotic angle (LKA). The results were compared within and between the groups. Survival function was analyzed. The criteria of an event were clinical or radiological deterioration versus pre-index surgery state. RESULTS: VAS was improved in the study group from 8.4 +/- 0.8 to 5.2 +/- 1.4, 6.4 +/- 1.2, 5.5 +/- 2.7, and 3.7 +/- 1.4 at postoperative day 1 and months 3, 6, and 12, respectively, and in the control group from 8.4 +/- 1.2 to 3.2 +/- 1.1, 3.2 +/- 1.7, 3.2 +/- 2.7, and 2.5 +/- 1.7, respectively (within group, p < 0.001; between groups, p < 0.001). VKA was improved in the study group from 18.9degrees +/- 8.0degrees to 15.2degrees +/- 6.1degrees (p = 0.046) and in the control group from 14.7degrees +/- 5.2degrees to 10.3degrees +/- 4.7degrees (p < 0.001) at postoperative day 1. LKA was not improved in the study group but was improved in the control group from 16.8degrees +/- 11.7degrees to 14.3degrees +/- 9.6degrees (p = 0.015). Correction angle was 2.7degrees +/- 4.6degrees, -7.9degrees +/- 5.3degrees, -7.2degrees +/- 5.2degrees, and -7.4degrees +/- 6.3degrees at postoperative day 1 and months 3, 6, and 12, respectively, in the study group and 4.3degrees +/- 3.7degrees, 0.7degrees +/- 3.6degrees, 0.7degrees +/- 4.2degrees, and 0.1degrees +/- 4.4degrees, respectively, in the control group. Correction loss was significant in both groups (p < 0.001) and more serious in the study group (p < 0.001). The 6-month survival rate was 16.7% in the study group and 64.3% in the control group (p = 0.003; odds ratio, 5.250). CONCLUSIONS: In treatment of osteoporotic vertebral fracture, fresh frozen allogeneic bone chips are not recommendable as a filler for its worse results than bone cement.

Projeto, fabricação e avaliação de implantes craniofaciais personalizados: proposta de utilização de materiais combinados / Design, production and evaluation of customized craniofacial implants: an approach on the use of different materials

Um material adequado para a reconstrução óssea craniofacial deve ser simples de implantar, possuir forma adequada, resistência à fratura e à deformação similares ao osso original, ser eventualmente substituído por osso natural, ser largamente disponível e não possuir um custo muito elevado. Baseado no fato de que um material com todas estas características ainda não está disponível atualmente, torna-se importante buscar novos materiais, novas composições e novas conformações. Diferentes biomateriais são utilizados atualmente para cirurgias de reconstrução craniofacial, cada um apresentando suas vantagens e limitações. Entre eles destacam-se o titânio, o polimetilmetacrilato e os cimentos de fosfato de cálcio. O titânio apresenta difícil conformação; o polimetilmetacrilato polimeriza-se por meio de uma reação exotérmica, podendo causar necrose de tecidos adjacentes ao implante; o cimento de fosfato de cálcio, por sua vez apresenta certa fragilidade, característica de alguns materiais cerâmicos. Neste sentido, este estudo examinou diferentes materiais utilizados para reconstrução craniofacial e suas propriedades mecânicas quando submetidos a ensaios de flexão, como o polimetilmetacrilato, o cimento de fosfato de cálcio e o cimento de fosfato de cálcio reforçado com titânio. Foi verificada a melhoria de propriedades mecânicas do cimento de fosfato de cálcio quando reforçado com malha de titânio. Além disso, este estudo apresenta uma técnica para o projeto e fabricação de implantes craniofaciais personalizados utilizando cimento de fosfato de cálcio reforçado com titânio, validada através de quatro casos de indicação cirúrgica de reconstrução craniofacial.

A material suitable for craniofacial reconstruction must be easy to implant, have the appropriate shape, have the strength and deformation similar to the original bone, be eventually substituted for natural bone, be widely available and present affordable costs. As such as material, with all theses characteristics is still not available, it is important to search for new materials, new compositions and new design. Different biomaterials are used nowadays for craniofacial reconstruction surgeries, each one presenting its advantages and limitations. Among these materials are the titanium, the poli(methilmetacrilate) and the calcium phosphate cements. Titanium presents hard conformation; poli(methilmetacrilate)’s polymerization reaction is exothermic, which may cause necrosis of the adjacent tissues; calcium phosphate cement is brittle, an usual characteristic of ceramic materials. In this way, this study evaluated different materials used for craniofacial reconstruction and its mechanical properties when submitted to bending test, such as poli(methilmetacrilate), calcium phosphate cement and calcium phosphate cement reinforced with titanium. It was verified the improvement in the mechanical properties of the calcium phosphate cement when reinforced with titanium mesh. In addition, this study presents a method for design and manufacturing of customized craniofacial implants using calcium phosphate cement reinforced with titanium mesh, validated through four cases of craniofacial reconstruction surgery indication.

Histological evaluation of the effects of bioglass, hydroxyapatite, or dernineralized freeze-dried bone, grafted alone or as composites, on the healing of tibial defects in rabbits

To compare the effectiveness of bioactive glass [BG], natural hydroxyapatite [HA], and demineralized freeze-dried bone [DFDB] in bone defects. All animal experiments were conducted in Faculty of Veterinary Medicine, Selcuk University, Konya, Turkey, under the Selcuk University Guidelines for Animal Experimentation, in 2005. Eighteen New Zealand rabbits were used for the experiment. Four cavities were prepared on right and left tibias. The cavities on the right tibia were filled with either BG, HA or DFDB. One cavity was left empty as a control. The cavities on the other tibial bone were grafted with HA+BG, HA+DFDB, BG+DFDB and HA+BG+DFDB composites. Histological examinations were performed at first, third, and sixth postoperative months. According to histomorphometric findings, the mixture containing HA+BG+DFDB obtained the best histological results [p < 0.05]. The composite graft of HA, BG and DFDB is more effective than when used as individual agents

Estudo experimental de implantes bioabsorviveis de poli(L-acido latico) / poli(oxido de etileno) associados ao cloridrato de vancomicina no reparo osseo / An experimental study of the use of bioabsorbable polyl(L-lactic acid) / poly(ethylene oxide) microspheres containing vancomycin for bone repair

A necessidade da utilização de enxertos naturais e/ou materiais sintéticos para auxiliar no reparo ósseo é diretamente proporcional a perda tecidual nas lesões. A administração de substâncias antibióticas é necessária para prevenir, ou mesmo combater a ação de agentes bacterianos que possam vir a retardar o reparo tecidual. Este estudo teve como objetivo avaliar a aplicação de um polímero bioabsorvível associado à uma droga antobiótica na regenereção óssea. Foram realizados implantes ósseos de microesferas da blenda de poli(L-ácido lático)PLLA/poli(óxido de etileno)PEO na composição 80:20 associadas ao cloridrato de vancomicina e não associados ao cloridrato de vancomicina em ratos. Os implantes foram colocados em cavidades de 3 mm de diâmetro realizadas em tíbias de ratos da linhagem Wistar. Grupos com 5 animais cada. foram submetidos a períodos experimentais de 2 e 4 dias e 1, 2, 4, 8, 16 e 32 semanas. Os achados morfológicos foram semelhantes em ambos grupos. Houve primeiramente a formação de malha de fibrina e hemorragia ao redor das microesferas, as quais foram gradualmente sendo substituídas por tecido de granulação. A partir do quarto dia, houve a formação inicial de matriz óssea envolvendo as microesferas centripetamente, tornando-se mais evidente e madura da primeira até a trigésima segunda semana de implantação. A comparação entre os achados histomorfométricos...

The use of natural graft and synthetic materials to help bone regeneration is directly relative to cause of bone injury and bone requirement to compose a graft. The antibiotics drugs management is necessary to prevent and combat bacterial agents that could retard the tissue repair The aim of this study was to evaluate the bioabsorbable polymeric implants antibiotic associated behavior during the bone healing. Poly(L-lactic acid)PLLA/poly(ethylene oxide)PEO microspheres blends 80:20 vancomicyn associated bone implants, was compared with PLLA/PEO blend without vancomycin. The implants were inserted in a 3 mm proximal tibiae defect in adult Wistar rats. Periods from 2 and 4 days and 1. 2, 4, 8 16 and 32 weeks were evaluated in 5 animals per group. The histological findings were similar among groups. A fibrin net and hemorrhage were observed primarily around the microspheres and both were progressively replaced by granulation tissue. In four-day implant, the initial bone formation around microspheres was noted. The growth of bone tissue was initially characterized by wolven bone with progressive maturation to lamellar bone, centripetally to microspheres group. The quantity of new bone growth, measured by histomorphometric method and semi-quantitative analysis showed no differences between groups in each experimental interval. Therefore we conclude that mixing vancomycin chloridrate into PLLA/PEO microspheres did not affect...