Mandibular reconstruction: platelet rich plasma & scaffolds.

Contains fulltext : 19540_mandire.pdf (publisher's version ) (Open Access)This thesis begins with a brief history of mandibular reconstruction. The use of growth factors is emphasized. The objective of this thesis is formulated: to investigate whether it is possible to perform a continuity resection of the mandibular angle and reconstruct the mandible using various scaffolds filled with an autogenous particulate cancellous bone graft taken from the iliac crest, mixed with PRP-gel. 46 goats underwent a continuity resection of the mandibular angle. Primary reconstruction was carried out using specially designed osteosynthesis plates and monocortical screws. The original cortical scaffold was used to bridge the defect, filled with an autogenous bone graft in 14 goats, whereas PRP was added in another 14 goats. In the third group of 12 goats, the cortical scaffold was irradiated before reimplantation. In another six goats the defect was bridged with a pre-shaped polylactid-acid(PDLLA) scaffold, filled with a bone graft with PRP. Radiological, histological and histomorphometric evaluation revealed that the use of PRP enhanced the bone healing considerably. In the PDLLA-group callus formation along the reconstructed segment was seen, providing bony continuity and maintaining the original contour. The particulate bone grafts within the PDLLA scaffold, however, showed considerable resorption and replacement by fibrous tissue. No plate fractures were seen and in only two goats screws turned out to be loose, without dislocation of the fragments. Because the plates are pre-shaped and heat-treated, there is less chance of metal fatigue. Chapter 6 describes the clinical application of the described techniques on eight patients who had partial mandibulectomies for malignant tumours. The histology showed bone remodelling in six cases with adequate functional and aesthetic outcome, given the poor conditions of the surrounding tissues. The presented method provides three-dimensional reconstruction with sufficient bone height and volume to facilitate prosthodontic treatment.KUN Katholieke Universiteit Nijmegen, 26 november 2004Promotores : Stoelinga, P.J.W., Jansen, J.A.188 p

Mandibular reconstruction: a histological and histomorphometric study on the use of autogenous scaffolds, particulate cortico-cancellous bone grafts and platelet rich plasma in goats.

Contains fulltext : 57151.pdf (publisher's version ) (Closed access)Twenty-eight goats underwent a continuity resection of the mandibular angle. In all goats primary reconstruction was carried out using specially designed pre-shaped osteosynthesis plates and monocortical screws. The original cortical scaffold was used to bridge the defect, filled with an autogenous particulate bone graft in 14 goats, whereas platelet-rich-plasma (PRP) was added in another 14 goats. Both groups were divided in three subgroups that were sacrificed after 3, 6 and 12 weeks. Histological and histomorphometric evaluation revealed that the use of PRP enhanced the bone healing considerably. This effect was statistically significant and particularly visible in the 6 and 12 weeks' group

Reconstruction of the mandible with an autogenous irradiated cortical scaffold, autogenous corticocancellous bone-graft and autogenous platelet-rich-plasma: an animal experiment.

Contains fulltext : 47424.pdf (publisher's version ) (Closed access)This paper reports on an experimental animal study evaluating a method of mandibular reconstruction using irradiated cortical scaffolds. Twelve goats underwent a continuity resection at the mandibular angle. Primary reconstruction was carried out using specially designed osteosynthesis plates and screws. The defect was bridged by the original, irradiated cortical scaffold, which was filled with an autogenous particulate bone graft from the anterior iliac crest. To accelerate bone healing, platelet rich plasma (PRP) was mixed with the particulate bone graft. The hypothesis of this study was that bone healing in segmental reconstruction of the goat mandible by means of an irradiated cortical scaffold, filled with a particulate cancellous bone graft mixed with PRP, would be as successful as when using a non-irradiated scaffold. All goats had an uneventful healing. The osteosynthesis plates and screws withstood immediate loading for periods varying from three to six weeks. The radiologic and histologic results were less favourable with regard to bone remodelling than the results obtained in similar experiments with non-irradiated cortical bone scaffolds

Reconstruction of the mandible using preshaped 2.3 mm titanium plates, autogenous particulate cortico-cancellous bone grafts and platelet rich plasma: a report on eight patients.

Contains fulltext : 57773.pdf (publisher's version ) (Closed access)The results are presented of eight patients who had partial mandibulectomies for malignant tumours and were secondarily reconstructed with pre-shaped 2.3 mm titanium plates, autogenous particulate cortico-cancellous bone grafts and platelet rich plasma. Healing was uneventful in all cases and when prosthodontically needed, implants were inserted after approximately 6 months, whilst biopsies were taken. The histology showed bone remodelling in six cases, whilst in one case after 6 months the bone was largely replaced by abundant fibrous tissue. In this case the implants were lost after 9 months. In one case a new carcinoma developed after 6 months with subsequent death of the patient. Thus, in six patients adequate results were achieved with adequate functional and aesthetic outcome, given the poor conditions of the surrounding tissues. This method provides three-dimensional reconstruction with sufficient bone height and volume to facilitate prosthodontic treatment

Plasma rico em plaquetas combinado a hidroxiapatita na formação do calo ósseo em fraturas induzidas experimentalmente no rádio de cães Platelet-rich plasma combined with hydroxyapatite on bone callus formation in experimental radii fractures in dogs

Avaliou-se, no presente estudo, os efeitos do plasma rico em plaquetas (PRP) autógeno combinado a hidroxiapatita não-absorvível na formação do calo ósseo em fraturas diafisárias induzidas experimentalmente em rádio de cães e fixadas com placas e parafusos ósseos. Foram utilizados oito cães adultos sem raça definida, machos ou fêmeas, com pesos compreendidos entre 5 e 15kg. Induziu-se na diáfise de ambos os rádios defeito ósseo correspondente a 25% do diâmetro do mesmo. No rádio direito (grupo HA/PRP), implantou-se plasma rico em plaquetas combinado a hidroxiapatita. No rádio esquerdo (grupo HA), implantou-se somente a hidroxiapatita. Para a obtenção do PRP, empregou-se protocolo simplificado utilizando centrífuga laboratorial comum. Comparou-se entre os grupos a evolução clínica dos animais, o tempo de formação e a densidade do calo ósseo por exames radiográficos simples e pela técnica de densitometria óptica aos 15, 30, 45 e 60 dias de pós-operatório. Tanto na avaliação radiográfica como densitométrica não se observou diferença estatisticamente significante na evolução do calo ósseo entre os grupos (P>0,05). No presente estudo, o PRP autógeno combinado à hidroxiapatita não-absorvível não acelerou o processo de formação do calo ósseo, comparado à hidroxiapatita somente.<br>The present study was aimed at evaluating the effects of autologous platelet-rich plasma (PRP) in combination with unabsorbable hydroxyapatite on bone callus formation in an experimental canine diaphyseal radius fracture stabilized with bone plate. Eight mature, male and female mongrel dogs were selected weighed 5 to 15kg. Bone defects were created, bilateral, in both radii diaphysis, corresponding to 25% of bone diameter. On the right radius (group HA/PRP), the defect was filled with PRP and hydroxyapatite. On the left radius (group HA), was placed hydroxyapatite alone. PRP was obtain by a simplified technique using a laboratory centrifuge. Clinical evaluations, bone formation and bone density by use of radiographic and optical densitometry, were compared between group HA/PRP and group HA after 15, 30, 45 and 60 days post surgery. The radiographic and densitometric study did not indicate a significant difference in the bone callus formation between the groups (P>0.05). In the present study the autologous PRP in combination with unabsorbable hydroxyapatite could not accelerated the bone callus in comparison with hydroxyapatite alone