Embolization was used to reduce the size of brain arteriovenous malformations (AVMs) prior to radiosurgical treatment in 125 patients who were poor surgical candidates or had refused surgery. Of these patients, 81% had suffered hemorrhage, and 22.4% had undergone treatment at another institution. According to the Spetzler-Martin scale, the AVMs were Grade II in 9.6%, Grade III in 31.2%, Grade IV in 30.4%, and Grades V to VI in 28.8% of the cases. Most embolizations were performed using cyanoacrylate delivered by flow-guided microcatheters. Radiosurgery was performed using a linear accelerator in 62 patients treated by the authors, and 34 patients were treated at other institutions using various methods. Embolization produced total occlusion in 11.2% of AVMs and reduced 76% of AVMs enough to allow radiosurgery. Radiosurgery produced total occlusion in 65% of the partially embolized AVMs (79% when the residual nidus was < 2 cm in diameter). Embolizations resulted in a mortality rate of 1.6% and a morbidity rate of 12.8%. No complications were associated with radiosurgery. The hemorrhage rate for partially embolized AVMs was 3% per year. No patient with a completely occluded AVM experienced rehemorrhage. Angiographic follow-up review of AVMs embolized with cyanoacrylate demonstrated a 11.8% revascularization rate, occurring within 1 year. It is concluded that after partial embolization with cyanoacrylate, the risk of hemorrhage from the residual nidus is comparable to the natural history of AVMs and that the residual nidus can be irradiated with results almost as good as for a native AVM of the same size.
This study compares the osteogenic effects of nacre and autogenous bone grafts in a rabbit model of lumbar spine transverse process arthrodesis. A total of 15 rabbits were processed for arthrodesis between the fifth and sixth lumbar vertebrae using nacre powder mixed with autologous blood or autogenous iliac crest bone. Control rabbits were sham operated. Sample vertebrae were removed from the nacre-implanted rabbits at 2, 5, and 11 weeks postsurgery. The autogenous bone graft and sham-operated groups were processed for histological study 11 weeks postsurgery. The results for the three groups were compared at 11 weeks. The nacre-implanted samples taken at 2 weeks showed that the nacre was well tolerated by the host tissue. Endochondral bone formation was seen in the region of the dissolving nacre particles by 5 weeks. The newly formed bone formed a solid fusion between the transverse processes in one-third of the rabbits. There was still new bone formation at 11 weeks at the nacre implant site. Two-thirds of the rabbits had formed a solid fusion. Light microscopy also showed new bone formation 11 weeks after the autologous bone graft.
The purpose of this study was to evaluate and compare plasma pharmacokinetics, lung tissue concentration, and the potential toxicity of drug eluting beads loaded with irinotecan (DEB-IRI) in a sheep pulmonary artery chemoembolization (PACE) model. Sheep (n = 24) were embolized with DEB-IRI loaded with different doses (0, 20, 50, or 100 mg). Direct pulmonary artery (PA) injections of irinotecan were also performed at two doses (50 or 100 mg; n = 4 sheep). Irinotecan was quantified in plasma and lung tissue (liquid chromatography-fluorescence detection); pathological examination of lungs was performed 4 days or 4 weeks after PACE. Irinotecan was detected in the systemic circulation within a few minutes after PACE, for several hours in DEB-IRI 20 and DEB-IRI 50 groups, and for 24 hours for DEB-IRI 100. Both Cmax and AUC values increased significantly with dose (p = 0.0078 and p = 0.0008, respectively) after PACE. Cmax and AUC values were significantly reduced (by 80%, p = 0.0036, and by 50%, p = 0.0393, respectively) after PACE than after direct PA injection. Irinotecan was not detected in tissue 4 days after PACE. No sign of lung toxicity was observed, except a limited hemorrhagic angionecrosis seen 4 days after PACE with DEB-IRI 100. Inflammatory response on beads was moderate in all DEB-IRI groups. Compared to other routes of administration, DEB loaded with irinotecan at doses up to 100 mg was well tolerated. DEB loaded with 100 mg irinotecan seem a promising candidate for future PACE trials in patients.
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