Laser-assisted fibrinogen bonding of umbilical vein grafts

Despite success with autologous tissue welding, laser welding of synthetic vascular prostheses has not been possible. The graft material appears inert and fails to allow the collagen breakdown and electrostatic bonding that results in tissue welding. To develop a laser welding system for graft material, we repaired glutaraldehyde-tanned human umbilical cord vein graft incisions using laser-assisted fibrinogen bonding (LAFB) technology. Modified umbilical vein graft was incised transversely (1.2 cm). Incisions were repaired using sutures, laser energy alone, or LAFB. For LAFB, indocyanine green dye was mixed with human fibrinogen and the compound applied with forceps onto the weld site prior to exposure to 808 nm diode laser energy (power density 4.8 W/cm 2). Bursting pressures for sutured repairs (126.6 +/- 23.4 mm Hg) were similar to LAFB anastomoses (111.6 +/- 55.0 mm Hg). No evidence of collateral thermal injury to the graft material was noted. In vivo evaluation of umbilical graft bonding with canine arteries demonstrates that LAFB can reliably reinforce sutured anastomoses. The described system for bonding graft material with laser exposed fibrinogen may allow creation or reinforcement of vascular anastomoses in procedures where use of autologous tissue is not feasible.     

Tissue anastomosis using a KTP laser: An experimental study

Summary

Sutured visceral anastomoses are time-consuming and complex when performed endoscopically. Theoretically, laser-welded visceral anastomoses are possible and are potentially easier and quicker to perform endoscopically than the sutured anastomoses. In this living canine study, we compared the operating time and intraluminal bursting pressure of laser-welded vs sutured anastomoses of (1) common bile duct (CBD), (2) small intestine, (3) colon and (4) ureter. Each organ was joined to itself using both anastomotic techniques. Welded anastomoses were much quicker in each organ system. Watertight anastomoses were achieved in each organ tested with both anastomotic techniques. Intraluminal hydrostatic bursting pressures occurred at lower pressures (approximately 70% of sutured anastomosis bursting pressure) in all organs. Though not qualified, tensile disruption pressure appeared to be significantly lower in the welded anastomoses as compared to the sutured anastomoses. Laser-welded visceral anastomoses are rapid and watertight. Compared to sutured anastomoses, welded anastomoses are less secure to intraluminal bursting pressures and probably less to tensile pressures. Strength enhancing adjunctive measures, such as serosal adhesives or serosal clips, may strengthen welded anastomoses and are worthy of additional studies.     

Fibrin glue is useful in preventing early dialysate leakage in children on chronic peritoneal dialysis.

OBJECTIVE: To assess if application of fibrin glue sealant to the peritoneal cuff suture is useful in the prevention of early dialysate leakage in children with end-stage renal disease on chronic peritoneal dialysis (CPD). DESIGN: Single-center, open-label, prospective randomized study. SETTING: University Pediatric Hospital. METHODS: 52 catheters were implanted in 45 children (mean age 6.2 +/- 4.5 years). Catheters were randomly assigned to either the control group or the sealant group. In the latter group, 1 mL of fibrin glue sealant was applied to the peritoneal cuff suture. 18 catheters were used for the first time within 5 days after implantation (early-used catheters). Leakage, exit-site or tunnel infection, peritonitis, and adverse secondary effects were evaluated during the initial 60 days after implantation. RESULTS: No adverse secondary effects were seen after the application of the fibrin glue sealant. The incidence of exit/tunnel infection and peritonitis was similar in the two groups. The incidence of leakage was significantly lower in the sealant group (p < 0.02). In the early-used catheters, leakage was detected in 9% of the catheters in the sealant group and in 57% of the control group (p < 0.05). CONCLUSIONS: The application of 1 mL of fibrin glue to the peritoneal cuff suture prevented early dialysate leakage without secondary adverse effects in children on CPD.     

Aorta and skin tissues welded by near-infrared Cr4+:YAG laser

OBJECTIVE: The aim of our study was to explore the wavelength dependence of welding efficacy. Ex vivo samples of human and porcine aorta and skin tissues were investigated using a tunable Cr(4+):yttrium aluminum garnet (YAG) laser. BACKGROUND DATA: Tissue welding is possible using laser light in the NIR spectral range. Collagen bonding in the tissue induced by thermal, photothermal, and photochemical reactions-or a combination of all of these-is thought to be responsible for tissue welding. Laser tissue welding (LTW) has gained success in the laboratory using animal models. Transition from laboratory to clinical application requires the optimization of welding parameters. MATERIALS AND METHODS: A near-infrared (NIR) Cr(4+):YAG laser was used to weld ex vivo samples of human and porcine aorta and skin at wavelengths from 1430 to 1470 nm. Welding efficacy was monitored by measuring the tensile strength of the welded tissue and the extent of collateral tissue damage. Tensile strengths were measured using a digital force gauge. Changes in tissue morphology were evaluated using optical and scanning electron microscope (SEM). Fluorescence imaging of the welded areas was also used to evaluate molecular changes following tissue welding. RESULTS: Full-thickness tissue bonding was observed with porcine aorta samples. No collateral damage of the aorta samples was observed. Tissue denaturation was observed with human aorta, human skin, and porcine skin samples. The optimum tensile strength for porcine and human aorta was 1.33 +/- 0.15 and 1.13 +/- 0.27 kg/cm2, respectively, at 1460 nm, while that for porcine and human skin was 0.94 +/- 0.15 and 1.05 +/- 0.19 kg/cm2, respectively, achieved at 1455 nm. The weld strength as a function of wavelength demonstrated a correlation with the absorption spectrum of water. Fluorescence imaging of welded aorta and skin demonstrated no significant changes in collagen and elastin emission at the weld site. CONCLUSION: The observation that welding strength as a function of wavelength follows the absorption bands of water suggests that absorption of light by water plays a significant role in laser tissue welding.     

A comparison of Cunyite and Fosterite NIR tunable laser tissue welding using native collagen fluorescence imaging.

OBJECTIVE: To evaluate the technique of native collagen fluorescence imaging for assessing the extent of welded areas for tissues exposed to different near-infrared (NIR) laser wavelengths. BACKGROUND: Native fluorescence imaging may be used to identify the distribution of collagen and elastin in tissues. Our past work demonstrated that different welding strengths were obtained under the same laser power conditions using different NIR wavelengths. The role of collagen in tissue welding experiments is not well understood. METHODS: Two new NIR tunable lasers were used to weld canine skin. The welded areas on the surface and in cross sections were analyzed by measuring the spatial distribution of native collagen fluorescence at 380 nm excited by 340 nm radiation. RESULTS: The results show that native collagen fluorescence imaging is a useful technique for analyzing the extent of tissue welds produced under a range of laser exposures. Fluorescence imaging reveals the depth of laser interaction with the tissue as well as evaluating collateral damage to the tissue surface. The welded volume obtained in skin using Cunyite laser exposure at 1,430 nm is deeper than that produced with Forsterite laser exposure at 1,250 nm. The post welded tensile strength for the same power density is greater for the Cunyite lasers. Ablated tissue on the surface is more prevalent with Forsterite laser welding at 1,250 nm than with Cunyite at 1,430 nm. CONCLUSION: Native collagen fluorescence can distinguish between tissue welds that have been produced by different NIR wavelengths. Tissue welding using 1,430 nm radiation is more effective than that using 1,250 nm.     

Alternative wavelengths for sutureless laser microvascular anastomosis: a preliminary study on acute samples

Attempts to improve the speed and patency of microvascular anastomosis with laser-assisted techniques have provided a modest reduction in operative time and comparable success rates. Using sutureless microvascular anastomoses, 30 end-to-end anastomoses were created in the rat carotid artery using the gallium-aluminum-arsenide diode laser (808 nm). Indocyanine green and fibrinogen were applied to enhance tissue absorption of the laser energy and strengthen the bond created. These were compared with previously reported welds using the THC:YAG laser (2150 nm). Mean welding times were 140 and 288 s, and mean bursting pressures immediately after welding were 515 and 400 mmHg for the diode and THC:YAG laser groups, respectively. Histologically, both lateral and vertical spread of thermal damage was limited. Since both lasers create welds of adequate initial strength without stay sutures and are faster and easier to use than existing systems, evaluation of long-term patency would be worthwhile.     

心脏镜多支冠状动脉搭桥术的动物实验研究

目的探讨心脏镜即不需辅助小切口的完全内镜下多支冠状动脉搭桥术术式的可行性。方法实验动物为2头猪和24条狗,胸壁打孔,进行多支冠状动脉搭桥手术的操作。结果经过1.5cm的3、4个小孔可以完成右冠状动脉、左冠状动脉、前降支、对角支及回旋支等多支冠状动脉的搭桥手术,并能顺利完成左锁骨下动脉、降主动脉的远端吻合口的吻合操作。结论心脏镜多支冠状动脉搭桥术切实可行,值得进一步研究。不久的将来有可能成为心脏搭桥术的主要术式。     

A new instrument for hemostatic vascular management in endoscopic surgery: diode laser (STATLase-SDL) and its handpiece (dual hook)

OBJECTIVE: The authors described experimental data in hemostatic vascular transection using a STATLase-SDL with a 780-865 nm GaA/As diode wavelength and its handpiece, Dual Hook (DH). SUMMARY BACKGROUND DATA: The STATLase-SDL and DH are newly developed devices for endoscopic surgery. It seems that the device has improved hemostatic cutting ability. METHODS: The DH was applied to the abdominal aorta (< 2 mm) of Japanese white rabbits (n = 15) under general anesthesia. Tissue temperature during laser transection and interluminal bursting pressures were measured. Histopathological examinations at the cut end were carried out by hematoxylin-eosin (H&E) and elastica Van Gleson's (EVG) stainings. To investigate short-term effects 11 days postoperatively, the cut ends of the vessels were examined histologically in the heminephrectomy group. RESULTS: The DH hemostatistically cut through arteries up to 2 mm in diameter. Temperatures at the inner hook and in adjunct tissue were higher than 160 degrees C, while that at the outer hook was lower than 80 degrees C. The bursting pressures immediately after transection was 307.2 +/- 35.2 mm Hg at a laser power of 8 W (n = 5), and 295.6 +/- 28.7 mm Hg at 10 W (n = 5). Histological examination of the transected sites on the vessels revealed well-opposed tissue welding of the vascular wall. Absence of fragmentation in the welding of the internal elastic lamina is crucial for closure of the vessel stump. Up to 11 days postoperatively, there were no direct complications related to the use of the DH. CONCLUSIONS: The STATLase-SDL and DH have good hemostatic cutting ability and might be suitable for endoscopic surgery.     

外源性碱性成纤维细胞生长因子对鞘内肌腱愈合和粘连的影响

背景：碱性成纤维细胞生长因子（basic fibroblast growth factor,bFGF）能促进体外腱细胞的增殖及胶原分泌，并促进鞘外肌腱的愈合，但其对鞘内肌腱的作用的资料较少。目的：探讨外源性bFGF对鞘内肌腱愈合和粘连形成的作用。设计、时间及地点：随机对照动物实验，于2004—05／200502在上海市第六人民医院实验动物中心实验室完成。材料：成年雄性来亭鸡90只制备鸡右爪第3趾趾深屈肌腱横断模型，随机均分为3组，每组30只。方法：对照组：肌腱横行切断后原位修复。纤维蛋白封闭剂组：在肌腱断端使用纤维蛋白封闭剂0．6uL后，原位修复肌腱。bFGF组：在断端使用bFGF和内含bFGF500ng的纤维蛋白封闭剂混合物0．6μL，原位修复叽腱。主要观察指标：术后1，2，4，8周，每组各取6只鸡进行大体、组织学检测：术后8周每组再取6只鸡进行生物力学测定。结果：对照组与纤维蛋白封闭剂组间各项观测指标比较均无显著性差别，与对照组和纤维蛋白封闭剂组相比，bFGF组修复部位腱鞘、腱外膜及腱实质的新生血管形成、成纤维细胞增殖较好，胶原的分泌出现早，数量也较多；肌腱滑动距离较短，屈曲功和肌腱最大抗拉力较大。结论：在肌腱断端使用外源性bFGF能促进鞘内肌腱的愈合，但也加重了肌腱的粘连。     

激光焊接新型钴铬合金的力学性能

背景：新型钴铬合金为一种不含镍和铍等有害成分的齿科合金材料,但关于其激光焊接的研究尚未见报道。目的：分析新型钴铬合金的激光焊接参数,优选激光焊接电压条件。方法：铸造0.5mm×6mm×30mm的新型钴铬合金试件60个,将试件分成6组。1组作为对照组;5组试件从中间断开,进行激光焊接,光斑直径设定为0.6mm,脉冲持续时间10ms,电压分别为220,250,280,310,340V,焊后进行拉伸强度测试,记录拉伸强度和延伸率。结果与结论：激光焊接新型钴铬合金拉伸强度随电压升高而增加。延伸率在电压低于280V时,随电压增大而增加;高于280V时,随电压增大而降低。电压为280V时,激光焊接新型钴铬合金的拉伸强度为（679.94±46.87）MPa,延伸率为（5.91±0.38）%。提示电压280V,脉冲持续时间10ms,光斑直径0.6mm条件下激光焊接新型钴铬合金的拉伸强度和延伸率均能满足临床要求。     

激光焊接新型钴铬合金的力学性能

背景:新型钴铬合金为一种不含镍和铍等有害成分的齿科合金材料,但关于其激光焊接的研究尚未见报道。目的:分析新型钴铬合金的激光焊接参数,优选激光焊接电压条件。方法:铸造0.5mm×6mm×30mm的新型钴铬合金试件60个,将试件分成6组。1组作为对照组;5组试件从中间断开,进行激光焊接,光斑直径设定为0.6mm,脉冲持续时间10ms,电压分别为220,250,280,310,340V,焊后进行拉伸强度测试,记录拉伸强度和延伸率。结果与结论:激光焊接新型钴铬合金拉伸强度随电压升高而增加。延伸率在电压低于280V时,随电压增大而增加;高于280V时,随电压增大而降低。电压为280V时,激光焊接新型钴铬合金的拉伸强度为(679.94±46.87)MPa,延伸率为(5.91±0.38)%。提示电压280V,脉冲持续时间10ms,光斑直径0.6mm条件下激光焊接新型钴铬合金的拉伸强度和延伸率均能满足临床要求。     

Fluorescence spectroscopic imaging to detect changes in collagen and elastin following laser tissue welding

OBJECTIVE: A study was performed to evaluate the use of native fluorescence imaging to detect in situ molecular changes. SUMMARY BACKGROUND DATA: There is no ideal noninvasive method to monitor molecular changes in a local region at a laser weld joint without removing a section of tissue for histological examination. METHODS: Two sections of animal skin were welded together border to border using a Ti:sapphire laser beam (800 nm). Fluorescence imaging was performed on the cross section of the welded site at specific emission wavelengths (lambda c) for collagen at 380 nm and for elastin at 450 nm using excitation wavelengths (lambda e) of 340 nm, and 380 nm, respectively. RESULTS: A reduction of the collagen and elastin emission was observed in the fluorescence images of the welded region. These results were confirmed with histology using picrosirius red F3BA under polarized light and orcein stains. CONCLUSION: Optical spectroscopic imaging offers a new noninvasive detecting method for microscopic evaluation of laser tissue welding.     

Flexor tendon repair using the two-strand side-locking loop technique to tolerate aggressive active mobilization immediately after surgery

BACKGROUND: Early mobilization after tendon repair decreases adhesion formation and improves repair-site strength. We investigated whether the two-strand side-locking loop technique would tolerate aggressive active mobilization immediately after surgery. METHODS: Twelve flexor digitorum profundus tendons of the porcine forelimbs were sutured by the two-strand side-locking loop technique with a cross-stitch epitendinous repair (Group A), and by the 8-strand repair method with a simple running suture (Group B). Gaps and residual tensile strength after cyclic loadings of 3-50 N (for 10,000 rounds) were measured. FINDINGS: Gaps after cyclic loading in Group A were 0.5+/-0.3 and 1.2+/-0.8 mm while those in Group B were 3.5+/-0.8 and 5.2+/-1.2 mm at 3 and 50 N, respectively. In addition, the respective residual tensile strength of Groups A and B were 207.1+/-15.2 and 84.2+/-18.3N. INTERPRETATION: A combination of the two-strand side-locking loop technique with cross-stitch epitendinous repair served as the optimum suture method in establishing safe and early active mobilization without the aid of a specialized rehabilitation staff.     

人工晶体单襻睫状沟单针双线缝线固定的临床观察

目的观察人工晶体单襻睫状沟单针双线缝线固定植入手术的安全性和有效性。方法对白内障后囊不完整的患者26例（26眼）采用单襻睫状沟单针双线缝线固定法植入后房型人工晶体。术中做以角巩为缘基底的3mm×3mm板层巩膜瓣,使用带两根聚丙烯缝线的长针先作巩膜瓣下缝针用作固定着力点,出针后再从巩膜垂直进针经前房在角膜光学区外3mm出针,剪去长针从白内障切口把聚丙烯缝线夹出,把两根聚丙烯缝线分别结扎人工晶体同一襻,两线结相距3mm,把人工晶体另一襻植入残存后囊上,结扎襻置入虹膜后,同时拉紧巩膜外缝线,调整人工晶体位置使其居中,将巩膜外两根缝线互相结扎,缩瞳,清除干净前房的玻璃体,透明质酸钠,观察术后视力,人工晶体位置,并发症及用药情况。术后随访1～6个月。结果26例（26眼）中术后1周裸眼视力〉10．5者19例（19眼）,占73．08％,术后1周裸眼视力0．1～0．4者7例（7眼）,占26．92％。人工晶体位置正常24例（24眼）,人工晶体位置偏位2例（2眼）。结论人工晶体单襻睫状沟单针双线缝线固定植入手术操作简便,并发症少,安全,效果良好。     

纤维蛋白封闭剂用于食管癌手术的临床分析

目的:探讨纤维蛋白封闭剂在食管癌根治术中的应用价值。方法:将食管癌患者62例,分为用胶组(27例)和未用胶组(35例),用胶组行常规食管癌根治术同时在手术创面应用纤维蛋白封闭剂,通过观察术后第12、24及48小时的胸腔闭式引流量及术后总引流量来确定纤维蛋白封闭剂在食管癌根治术中的有效性。结果:用胶组术后第12、24及48小时的胸腔闭式流量及术后总引流量均少于未用胶组,差异具有非常显著性(P<0.01)。结论:食管癌根治术中应用纤维蛋白封闭剂可以有效减少术后引流量,提早拔除胸腔闭式引流管,有利于患者的术后恢复。     

激光焊接大鼠颈动脉的生物力学研究

目的从生物力学角度探讨单一激光焊接大鼠颈动脉的可行性.方法选用Wistar大鼠80只,分为激光焊接组和缝合组.于术后采取吻合口在内的血管进行生物力学测试.结果激光焊接血管最大抗拉强度28d前低于缝合血管组.激光焊接血管最大破裂压14d前低于缝合血管组.大鼠术后吻合口无破裂并且能够长期存活,说明激光焊接血管能够满足大鼠生理需要.结论单一激光焊接大鼠颈动脉可行、有效.     

Gamma-irradiation markedly inhibits the hydrated collagen gel contradiction by arterial smooth muscle cells.

BACKGROUND: Vessel wall responses to percutaneous transluminal coronary angioplasty include neointimal proliferation and arterial remodeling. The contraction of a collagen gel is a good in vitro model of wound repair and vascular remodeling. Because irradiation is an important new therapeutic modality capable of preventing restenosis, the purpose of this study was to evaluate the effect of irradiation on the contraction of a collagen gel by smooth muscle cells (SMCs), on SMCs viability, and on DNA synthesis. METHODS: We studied the effect of different doses of gamma-irradiation (0 [control], 6, 12, and 18 Gy) on the contraction of a collagen gel seeded with SMCs (calf carotid arteries) during a period of 15 days. RESULTS: Maximal gel diameter reduction (from 35 to 6.8 mm, +/-0.5 mm in control) was markedly inhibited in the 6-, 12-, and 18-Gy groups (35 to 13.7 mm, +/-0.8 mm; 35 to 15.5 mm, +/-0.9 mm; and 35 to 16.1 mm, +/-0.9 mm, respectively; P<0.0001). The irradiated gels showed a dose-dependent reduction in the SMC proliferation rate (P<0.0001) and an increase in the number of nonviable SMCs (P<0.002) 15 days after irradiation. CONCLUSIONS: Gamma-irradiation produces a significant dose-dependent inhibition of the contraction of collagen gels seeded with arterial SMCs. This effect is related to a significant decrease in SMC viability and a decrease in SMC proliferation rate. These findings shed light on mechanisms whereby irradiation may positively affect arterial remodeling after percutaneous transluminal coronary angioplasties.     

下肢股腘动脉搭桥术中应用复合移植物6例报告

目的：为寻求一种有效的长距离膝下移植物来治疗下肢动脉长段阻塞或动脉旁路 远端动脉阻塞,方法：自１９９５年２月～１９９９年２月采用复合移植物治疗下肢股Ｕｕｏ动脉硬化闭塞症共６例,包括（１）“直接式”吻合法;（２）“跳跃式”吻合法;（３）“连贯式”吻合法：即先做膝上股Ｇｕｏ动脉人造血管移植。再做人造血管－自体大隐静脉－膝下Ｇｕｏ动脉端侧吻合。结果：经术后３年随访,６例中４例症状消失,２例症状同术前,结论：当无法应用单一的大隐静脉或人造血管时,复合移植物对治疗下肢股瘤动脉长段闭塞,特别是病变累及膝下动脉时,是合适的血管代用品。     

Comparison between self‐assembling peptide nanofiber scaffold (SAPNS) and fibrin sealant in neurosurgical hemostasis

RADA16‐I is a synthetic type I self‐assembling peptide nanofiber scaffold (SAPNS) which may serve as a novel biocompatible hemostatic agent. Its application in neurosurgical hemostasis, however, has not been explored. Although RADA16‐I is nontoxic and nonimmunogenic, its intrinsic acidity may potentially provoke inflammation in the surgically injured brain. We conducted an animal study to compare RADA16‐I with fibrin sealant, a commonly used agent, with the hypothesis that the former would be a comparable alternative. Using a standardized surgical brain injury model, 30 Sprague–Dawley rats were randomized into three treatment groups: RADA16‐I, fibrin sealant or gelatin sponge (control). Animals were sacrificed on day 3 and 42. Astrocytic and microglial infiltrations within the cerebral parenchyma adjacent to the operative site were significantly lower in the RADA16‐I and fibrin sealant groups than control. RADA16‐I did not cause more cellular inflammatory response despite its acidity when compared with fibrin sealant. Immunohistochemical studies showed infiltration by astrocytes and microglia into the fibrin sealant and RADA16‐I grafts, suggesting their potential uses as tissue scaffolds. RADA16‐I is a promising candidate for further translational and clinical studies that focus on its applications as a safe and effective hemostat, proregenerative nanofiber scaffold as well as drug and cell carrier.     

Correlation between acid-base parameters measured in arterial blood and venous blood sampled peripherally, from vena cavae superior, and from the pulmonary artery.

OBJECTIVE: In intensive care units arterial blood sampling is routine for analysing acid-base and oxygenation status. In nonintensive departments arterial blood sampling is seldom performed. Venous blood sampling is routine but not usually analysed for acid-base and oxygenation status. This study describes the correlation between arterial and peripheral, central and mixed venous pH, PCO2 and PO2 in a wide range of adult patients. METHODS: Arterial and venous blood samples were taken anaerobically and simultaneously. The values of pH, PCO2 and PO2 were compared using Bland-Altman plots. RESULTS: A total of 103 patients were included. The arteriovenous difference (bias+/-SD) for pH was 0.026+/-0.023 and for PCO2 -0.60+/-0.57 kPa (peripheral venous blood), 0.036+/-0.014 and -0.79+/-0.26 kPa (central venous blood) and 0.026+/-0.010 and -0.67+/-0.22 kPa (mixed venous blood). The arteriovenous difference for PO2 for peripheral, central and mixed venous blood was 6.27+/-4.36, 8.33+/-3.94 and 11.00+/-4.87 kPa, respectively. CONCLUSION: The venous values of pH, corrected for bias, can give arterial values which are within reasonable laboratory and clinical acceptance criteria. For PCO2 this is also true, except for peripheral blood, where the standard deviation is outside laboratory acceptance criteria but within clinical acceptance criteria. For PO2 the arteriovenous differences are not randomly distributed and even for PO2相似文献