Abstract:Objective To evaluate the effect of external stents on preventing vein graft neointima formation and medial thickening with non-restrictive macro porous polyester stent around porcine vein grafts. Methods Studies were performed by using ＂white race＂ pigs （n= 10） weight 25-30 kg. All the animals underwent bilateral saphenous vein into carotid artery bypass grafting. In each animal, a maeroporous stent was placed around a graft on one side and a control （unstented） graft on the opposite side. The polyester stent was shaped to cover both anastomoses completely. The size of the stem allowed unrestricted expansion of the graft in initial response to arterial pressure. After 35 days of surgery,all animals were taken to remove the grafts. Graft wall dimensions, platelet- derived growth factor （PDGF） expression and cell proliferation using proliferating cell nuclear antigen （PCNA） were measured on histological sections. Results Stents significantly reduced neointimal thickening （0. 4872 ± 0. 0706 mm vs. 0. 2259± 0. 0553mm,P〈0. 01）and medial thickening （0. 6246±0. 0859mm vs. 0. 4201±0. 0615mm,P〈0. 01）. Stents significantly reduced the percentage of cells expressing PDGF and PCNA. Media, intimal PCNA index was reduced from 7. 980/00± 4. 060/00 to 3.35±0.95%（P〈0.01）, PDGF index was reduced from 9.47%±5.35% to 2.67%± 0.97% （P 〈0. 01）. Conclusion External non-restrictive polyester stent can significantly inhibit neointimal formation and medial thickening, and may prevent late vein grafts restenosis.
【摘要】 目的 评价切开复位Herbert螺钉内固定加外支架治疗对亚急性和陈旧性舟状骨骨折的治疗效果。方法 2008年2月—2009年5月,对15例受伤后4周以上(平均7.6周)入院诊断为亚急性和陈旧性舟状骨骨折的患者均采用Herbert螺钉内固定加外支架治疗,术后随访5～16个月,平均12.5个月,按Gartland amp; Werley和改良Green amp; O’Brein评分系统进行评价治疗效果。结果 15例患者均进行有效随访,末次随访Gartland amp; Werley评分优8例,良5例,中2例,优良率为86.7％,改良Green amp; O’Brein评分优7例,良5例,中3例，优良率为80％。结论 此方法是治疗亚急性和陈旧性舟状骨骨折的有效措施,值得推广。
ObjectiveTo investigate the effectiveness of the Ilizarov technique for the treatment of traumatic talipes equinovarus so as to provide the evidence for the clinical practice. MethodsBetween February 2011 and April 2012,42 patients with traumatic talipes equinovarus received treatment by Ilizarov technique,including 29 males and 13 females aged 17-55 years (mean,34.3 years).The left side was involved in 24 cases,and the right side in 18 cases.The disease duration was 6 months to 6 years (mean,2.7 years).According to the principles of Ilizarov,a ring external fixator was applied on the affected foot and lower leg.The threaded rods and screw nuts were revolved according to the tolerance of patients at 3-7 days after fixation.At first,forefoot varus or foot inversion was corrected,and then drooping feet deformity was corrected.The patients were encouraged to begin weight-bearing walking after correction.X-ray films were taken regularly to observe the ankle joint and avoid its dislocation.The external fixator was maintained in neutral position for 8-12 weeks after achieving satisfactory correction.An walking ankle-foot orthosis and a sleeping ankle-foot orthosis were used for more than 16 weeks after removal of the fixator.The outcome was assessed with American Orthopaedic Foot and Ankle Society (AOFAS) comprehensive scoring system and visual analogue scale (VAS) pain score. ResultsForty-two patients were followed up 14.3 months on average (range,10-24 months).All the patients achieved 0° dorsiflexion at 4-13 weeks (mean,6.8 weeks) after treatment with Ilizarov apparatus.The fixator was maintained for 10.7 weeks on average (range,10-16 weeks) after correction.No dislocation of the ankle joint and no damage to nerves and blood vessels occurred.The deformity of plantar flexion (10°) was found in 3 patients.At last follow-up,the patients could walk normally.AOFAS score was significantly increased to 93.4±8.0 from 52.7±10.1 at preoperation (t=-7.035,P=0.008);according to AOFAS scoring system,24 cases were grades as excellent,14 as good,2 as moderate,and 2 as poor,and the excellent and good rate was 90.5%.The VAS score of the foot significantly decreased to 3.51±1.44 from 7.55±1.39 at preoperation (t=-0.564,P=0.025). ConclusionIlizarov technique combined with non-fusion has satisfactory effectiveness in correction of traumatic talipes equinovarus.It is a safe,effective,and minimally invasive method.
Objective To evaluate the safety of conversion from external fixation to internal fixation for open tibia fractures. Methods Between January 2010 and December 2014, 94 patients (98 limbs) with open tibia fractures were initially treated with external fixators at the first stage, and the clinical data were retrospectively analyzed. In 29 cases (31 limbs), the external fixators were changed to internal fixation for discomfort, pin tract response, Schantz pin loosening, delayed union or non-union after complete wound healing and normal or close to normal levels of erythrocyte sedimentation rate (ESR), C reactive protein (CRP), and the leucocyte count as well as the neutrophil ratio (trial group); in 65 cases (67 limbs), the external fixators were used as the ultimate treatment in the control group. There was no significant difference in gender, age, side of the limbs, interval from injury to the first debridement, initial pathogenic bacteria, the limbs that skin grafting or flap transferring for skin and soft tissue defect between the two groups ( P>0.05). The incidence of Gustilo type III fractures in the control group was significantly higher than that in the trial group (P=0.000). The overall incidence of infection was calculated respectively in the two groups. The incidence of infection according to different fracture types and whether skin grafting or flap transferring was compared between the two groups. The information of the pathogenic bacteria was recorded in the infected patients, and it was compared with the results of the initial culture. The incidence of infection in the patients of the trial group using different internal fixation instruments was recorded. Results The overall incidences of infection for the trial and control groups were 9.7% (3/31) and 9.0% (6/67) respectively, showing no significant difference (χ2=0.013, P=0.909). No infection occurred in Gustilo type I and type II patients. The incidence of infection for Gustilo type IIIA patients in the trial group and the control group were 14.3% (1/7) and 6.3% (2/32) respectively, showing no significant difference (χ2=0.509, P=0.476); the incidence of infection for type IIIB patients in the two groups were 50.0% (2/4) and 14.3% (2/14) respectively, showing no significant difference (χ2=2.168, P=0.141); and the incidence of infection for type IIIC patients in the two groups were 0 and 16.7% (2/12) respectively, showing no significant difference (χ2=0.361, P=0.548). Of all the infected limbs, only 1 limb in the trial group had the same Staphylococcus Aureus as the result of the initial culture. In the patients who underwent skin grafting or flap transferring, the incidence of infection in the trial and control groups were 33.3% (2/6) and 13.3% (2/15) respectively, showing no significant difference (χ2=1.059, P=0.303). After conversion to internal fixation, no infection occurred in the cases that fixed with nails (11 limbs), and infection occurred in 4 of 20 limbs that fixed with plates, with an incidence of infection of 20%. Conclusion Conversion from external fixation to internal fixation for open tibia fractures is safe in most cases. However, for open tibia fractures with extensive and severe soft tissue injury, especially Gustilo type III patients who achieved wound heal after flap transfer or skin grafting, the choice of secondary conversion to internal fixation should carried out cautiously. Careful pre-operative evaluation of soft tissue status, cautious choice of fixation instrument and meticulous intra-operative soft tissue protection are essential for its safety.
External support stent is a potential means for restricting the deformation and reducing wall stress of the vein graft, thereby improving the long-term patency of the graft in coronary artery bypass surgery. However, there still lacks a theoretical reference for choosing the size of stent based on the diameter of graft. Taking the VEST (venous external support) stent currently used in the clinical practice as the object of study, we constructed three models of VEST stents with different diameters and coupled them respectively to a model of the great saphenous vein graft, and numerically simulated the expansion-contraction process of the vein graft under the constraint of the stents to quantitatively evaluate the influence of stent size on the radial deformation and wall stress of the vein graft. The results showed that while the stent with a small diameter had a high restrictive effect in comparison with larger stents, it led to more severe concentration of wall stress and sharper changes in radial deformation along the axis of the graft, which may have adverse influence on the graft. In order to solve the aforementioned problems, we ameliorated the design of the stent by means of changing the cross-sectional shape of the thick and thin alloy wires from circle into rectangle and square, respectively, while keeping the cross-sectional areas of alloy wires and stent topology unchanged. Further numerical simulations demonstrated that the ameliorated stent evidently reduced the degrees of wall stress concentration and abrupt changes in radial deformation, which may help improve the biomechanical environment of the graft while maintaining the restrictive role of the stent.
In the American Heart Association’s Scientific Sessions 2021, the results of six clinical trials related to cardiovascular surgery were revealed. The PALACS trial demonstrated that posterior left pericardiotomy during open heart surgery was associated with a significant reduction in postoperative atrial fibrillation; the EPICCURE study found that injection of mRNA encoding vascular endothelial growth factor (VEGF-A mRNA) directly into the myocardium of patients undergoing elective coronary artery bypass grafting (CABG) improved patients’ heart function; the VEST trial once again proved the safety and potential value of external stent for vein graft. This article will interpret the above-mentioned three studies.