The role of bone SPECT/CT in the evaluation of lumbar spinal fusion with metallic fixation devices.

Purpose: It is difficult to evaluate the stability of the lumbar spondylodesis with metallic fixation devices by conventional imaging methods such as radiography or magnetic resonance imaging. It is unknown whether single photon emission computed tomography/computed tomography (SPECT/CT) may be useful to detect a lack of fixation of the pedicle screws and hence to predict instability of the fused vertebral segments.

Materials And Methods: A retrospective analysis of 9 patients who were referred to bone scintigraphy, including combined SPECT/CT, due to persistent pain or discomfort after stabilizing lumbar surgery with metallic implants.

[Bilateral Achilles tendon rupture in individuals with renal transplantation].

Increased incidence of tendinitis and tendon ruptures is reported in recipients of a kidney transplant. Two cases of bilateral achilles tendon rupture after minimal trauma are described. Tendon ruptures are more frequent in individuals with kidney disease in dialysis or after transplantation compared with patients receiving other organ transplantations.

Interface mechanics and histomorphometric analysis of hydroxyapatite-coated and porous glass-ceramic implants in canine bone.

A canine study was performed to make a histological and biomechanical evaluation of the interface between bone and two different bioceramic implants. A newly developed glass-ceramic formed by P2O5, CaO, SiO2, and Al2O3, giving a crystal phase composed of CaP2O6-AlPO4-SiP2O7, was compared to hydroxyapatite (HA) coated Ti-6Al-4V implants. A total of 24 implants were inserted into the femoral condyle of 15 adult female golden retriever dogs weighing 20-25 kg.

Blood perfusion and remodelling activity in canine tibial diaphysis after filling with a new bone cement compared to bone wax and poly(methyl methacrylate) cement.

Six dogs each had one tibia filled with standard poly(methyl methacrylate) (PMMA) bone cement and the contralateral tibia filled with a new methyl methacrylate-n-decyl methacrylate-isobornyl methacrylate (MMA-DMA-IBMA) bone cement (Boneloc) with lowered polymerization heat and monomer leakage. An additional six dogs each had one tibia filled with MMA-DMA-IBMA and the contralateral tibia filled with bone wax. There was a higher diaphyseal blood flow, measured with a microsphere technique, in the legs filled with MMA-DMA-IBMA than in those filled with PMMA.

Immediate implant placement using a biodegradable barrier, polyhydroxybutyrate-hydroxyvalerate reinforced with polyglactin 910. An experimental study in dogs.

The purpose of this study was to evaluate the use of a biodegradable membrane of polyhydroxybutyrate-hydroxyvalerate copolymer reinforced with polyglactin 910 fibers, as an occlusive barrier over implants placed into fresh extraction sockets. Ten dogs had the 3rd and 4th mandibular premolars extracted bilaterally. Each dog had 4 Astra Dental Implants placed directly into the fresh extraction sockets.

Effects of polymerization heat and monomers from acrylic cement on canine bone.

We investigated the effects of polymerization heat and toxicity of polymethylmetacrylate bone cement in the canine tibial diaphysis. Heat was studied by filling the tibias with either bone cement or bone wax contained in a monomer tight membrane pouch. Toxicity was studied by filling both tibias with cement, with the control side contained in the membrane pouch.

Variation of cortical hypertrophy depending on the medullary filling material. An experimental study of canine tibial diaphysis.

In order to evaluate the mineralization of bone after polymethyl methacrylate cementation, measurements of the periosteal apposition were made histologically and measurements of the bone-mineral content were made by dual-photon absorptiometry of the tibial diaphysis in 15 adult mongrel dogs in paired studies. Six dogs were investigated 4 weeks after intramedullary reaming of both sides and obturation of the medullary cavity with bone-wax on one side. Nine dogs were reamed on both sides.

Evaluation of guided bone generation around implants placed into fresh extraction sockets: an experimental study in dogs.

Immediate placement of implants into fresh extraction sockets would have the principal advantage of decreasing the recommended period of healing. It also would result in a guided placement of the implant, and it could reduce the resorption of the alveolar bone in the extraction area. However, when an implant is placed immediately into an extraction socket, it may not engage the walls of the socket near the crest of the alveolar ridge.

Improved cortical histology after cementation with a new MMA-DMA-IBMA bone cement: an animal study.

The histological response of bone to inert bone wax, conventional polymethylmethacrylate (PMMA), and a new formulation of bone cement, methylmethacrylate/n-decylmethacrylate/isobornylmethacrylate (MMA/DMA/IBMA) was investigated in canine tibial diaphysis. The new formulation of cement is characterized by a reduced exothermic temperature at curing and reduced leakage of chemicals to the adjacent bone. In comparison with bone wax, the MMA/DMA/IBMA bone cement did not differ significantly with respect to periosteal apposition and bone remodeling, although a tendency to inhibit the biological response was encountered.

Mechanical failure of hydroxyapatite-coated titanium and cobalt-chromium-molybdenum alloy implants. An animal study.

Defects in the hydroxyapatite (HA) ceramic coatings applied to metallic implant systems may occur at the time of insertion or at the time of in vivo loading. However, defects may also occur with time because of interaction with physiological fluids. A canine study was performed to make a histological and biomechanical evaluation of HA-coated titanium and cobalt-chromium-molybdenum alloy implants in a non-weight-bearing model.

Histomorphometric and removal torque analysis for TiO2-blasted titanium implants. An experimental study on dogs.

The aim of the present study was to compare the anchorage of TiO2-blasted screw and cylindrical implants with conventionally used machine-produced screw and cylindrical implants inserted immediately in extraction sockets on dogs. 6 adult mongrel dogs had 3rd and 4th mandibular premolars extracted bilaterally and 24 commercial pure titanium implants were placed immediately in extraction sockets and covered with mucoperiosteum. Each dog had inserted 4 implants: 1 screw implant and 1 cylindrical implant blasted with titanium-dioxide-particles; 1 screw implant and 1 cylindrical implant with machine-produced (m.

The effect on cortical bone of reaming and filling of canine tibial diaphysis with inert bone wax.

In canine studies the effect of intramedullary reaming on tubular bone was investigated in 4 dogs. Intramedullary reaming was further compared with reaming and intramedullary filling with bone wax in 6 dogs. Bone blood perfusion was measured by a microsphere technique and bone remodelling activity by 99mTc-MDP uptake.