The use of lumbar fusion procedures in the USA and Europe has rapidly increased over the last decade and a large number of these procedures involve the use of bone grafts. Despite of technical progress of spinal surgery and operative materials the risk of vertebral fusion failure occurs in 5 – 35 % of cases. Autografting has been considered the gold standard for bone graft procedures. However, the harvesting from the iliac crest can be associated with short and long-term morbidity in up to 22 % of cases. Main goal of this experimental study was to compare newly developed hybrid biodegradable nanocomposit porous implant (HBNPI) against bone craft from iliac crest as a new and better alternative for lumbar interbody fusion. 24 male pigs 4 months old weighting around 40 Kg were included in our study. These pigs were divided into two study groups depending on fusion method. Group A – 12 pigs underwent lateral lumbal interbody fusion (L2/3) with implantation of iliac crest bonegraft. Group B - 12 pigs underwent lateral lumbal interbody fusion (L2/3) with newly developed HBNPI. Each group were divided into two subgroups from these 6 spines were harvested 8 weeks (subgroup A1, B1) and 6 spines 16 weeks (group A2, B2) after surgery. After sacrifice, the lumbar spines were taking out and micro-CT, biomechanical testing and histomorphological analysis in all groups were performed to evaluate a quality of intervertebral fusion. As controls (group N), 6 cadaveric intact lumbar spines underwent biomechanical, micro-CT and histological testing. All 24 animals recovered from general anesthesia without unusual events. The operations lasted between 50–90 minutes (mean 70) in Group A and between 35–72 minutes (mean 43) in Group B. All of the pigs from group A could stand up and were mobile within 20 hours (range 7–20). When bone graft harvesting was not necessary (group B) this time was shortened, ranging from 1 – 1,5 hour. All pigs from Group A were limping on the first postoperative day. No limping animal was observed in group B. Total body weight of the pigs increased from 37 kg (range 36–40) at the start to 85 (range 80–89) at sacrifice. Biomechanics evaluation shows that extension flexural stiffness values are statistically significantly different between A2 (16 weeks post-implant) and A1 (8 weeks post-implant). Group A2 achieves higher values than Group A1, which is attributed to the adhesion of the implant to the surrounding vertebrae. Similarly, this also applies to groups B2 and B1. The flexural stiffness at group B2 extension is statistically significantly higher than the A2 group and also than the native N group. Biomechanical evaluation supports findings on micro-CT and histological specimens, where both adjacent vertebrae are completely fused in groups B2, unlike in group A2, where there is no or incomplete fusion. Newly developed HBNPI represents new possibility how to do intervertebral fusion, and simultaneous become chance how to improve and accelerate bone healing process against standard procedures.
Juvenile bone cysts in children and adolescents are often discovered incidentally or in connection with a pathologic fracture. Although the diagnostic procedure in this type of lesion affecting the skeleton has become uniform, the treatment varies according to the principles established at different clinics. The aim of our study was to compare two Methods: applied in the treatment of juvenile bone cysts, i.e. the established method of a series of Methylprednisolone injections and a new mini-invasive method using a Tricalcium phosphate. In both groups of patients, we performed an evaluation of the number of required surgeries, general anaesthesias and subsequent hospitalizations (including the length of hospitalization), the treatment results and the interval between surgery and complete cyst healing using Neer’s evaluation criteria. The group of patients treated with Methylprednisolone consisted of 24 patients and the group of patients treated with Tricalcium phosphate comprised 20 patients. The outcome of the statistical analysis proves that in patients treated with Tricalcium phosphate significantly better results were obtained compared to patients where Methylprednisolone was applied. A subsequent surgery (additional application) was necessary only in two Tricalcium phosphate patients (10%) compared to nineteen Methylprednisolone patients (79%). The average length of hospitalization was 4 days in Tricalcium phosphate patients and 3.5 days in Methylprednisolone patients. Excellent and good results according to the Neer classification were documented in eighteen Tricalcium phosphate patients (19%) and in twelve Methylprednisolone patients (50%). The treatment of juvenile bone cysts with a biocompatible resorbable synthetic filler Tricalcium phosphate helps reduce the number of surgeries necessary for complete cyst healing and produces better results in terms of Neer’s evaluation criteria of bone cyst treatment results compared to the application of Methylprednisolone into the cyst. This work was supported by the Internal Grant Agency of the Ministry of Health of the Czech Republic (NS9860-3/2008).
Mesenchymal stem cells (MSCs) from bone marrow are multipotent cells capable of forming cartilage, bone, and other connective tissues. The objective of this study was to determine whether the use of allogenic mesenchymal stem cells could functionally heal defect in the distal femoral physis in rabbits without the use of immunosuppressive therapy. An iatrogenic defect was created in the lateral femoral condyle of thirty-two New Zealand white rabbits, 7 weeks old, that weighed 2.25 ? 0.24 kg. Each defect, 3.5 mm in width and 12 mm in length, in the right distal femoral physis was treated with allogenic mesenchymal stem cells in new composite hyaluronate/ collagen type I/fibrin scaffold. The healing response was evaluated radiographically, by MRI (at three weeks and four months after implantation), and also histologically, by Pearls’ reaction and with immunofluorescency (at four months after implantation). The results were compared with the data for the control defects (without stem cell implantation) in left distal femoral physes. In average, right femurs with damaged distal physis and transplanted MSCs grew more in length (0.55? 0.21 cm) as compared with left femurs with physeal defect without stem cell transplantation (0.46? 0.23 cm). Valgus deformity of right femurs with physeal defect and transplanted MSCs was mild (0.2? 0.1°). On the contrary, left femurs with physeal defect without transplantated MSCs showed significant valgus deformity (2.7? 1.6°). For defects treated with allogenic mesenchymal stem cell implants, no adverse immune response and implant rejection were detected in this model. Histologically, no lymphocytic infiltration occurred. At four months after transplantation, hyalinne cartilage had formed throughout the defects treated with allogenic MSCs. Labeled mesenchymal stem cells/diferentiated chondrocytes were detected in the physeal defects based on magnetic resonance imaging and immunofluorescency. The results of this study demonstrated that allogenic mesenchymal stem cells in a new composite hyaluronate/collagen type I/fibrin scaffold repaired iatrogenic defects in the distal femoral physes in rabbits without the use of immunosuppressive therapy. The use of allogenic mesenchymal stem cells for the repair of physeal defects may be an alternative to autologous MSCs transplantation. An allogenic approach would enable mesenchymal stem cells to be isolated from any donor, providing a readily available source of cells for cartilage tissue repair.
Physeal cartilage is known to have poor self-repair capacity after injury. Evaluation of the ability of cultured mesenchymal stem cells to repair damaged physis is the actual research topics. In 10 immature New Zealand white rabbits autogenous mesenchymal stem cells were transplanted into iatrogenic physeal defect in lateral portion of distal growth plate of the right femur. The same defect without stem cells transplantation in the left femoral distal physis served as a control. In our study, we used our own technique of implantation of MSCs with a newly modified gel scaffold (New Composite Hyaluronate/Collagen Type I/Fibrin Scaffold). The rabbits were euthanized 4 months after transplantation. Bone length discrepancy and valgus deformity were measured from femoral radiographs. Healing of the defect was investigated histologically. The ability of mesenchymal stem cells to survive and promote cartilage healing in the physeal defect was assessed by immunofluorescence. Average difference in femur length measured from surgery to euthanasia (4 months) was 0.61? 0.19 cm after preventive transplantation of MSCs in right femur, but only 0.11 ? 0.07 cm in left femur. Average angular (valgus) deformity of right femur with MSCs preventively transplanted to iatrogenically damaged distal femoral physis was 1.2? 0.72°. Valgus deformity in left femur was 5.4? 2.5°. Prophylactic transplantation of autogenous mesenchymal stem cells to iatrogenically damaged distal growth plate of rabbit femur prevented bone bridge formation and resulted in healing of the physeal defect with hyaline cartilage. Immunofluorescence examination showed that the chondrocytes newly formed in growth zone are the result of implanted MSCs differentiation. Femur growth in traumatized physis was maintained even after transplantation of autogenous MSCs. As compared with the opposite femur (with physeal defect but without transplanted MSCs), the bone showed no significant shortening or valgus deformity (p=0.018).
