Bursting pressures of CO2 laser-welded rabbit ileum

In this study, the short-term bond strength of laser-welded New Zealand white rabbit ileum was examined. Forty-eight longitudinally oriented 0.5-cm transmural, scalpel incisions were reanastomosed solely through the use of the CO2 continuous wave laser at low energy levels. Random power levels of 250, 500, 750, or 1,000 mW were delivered to weld sites by either continuous application for 30 seconds or a pulsating application (ie, 0.5 seconds on, 0.5 seconds off) for 60 seconds. This provided 53.6, 107.1, 160.7, and 214.3 J/cm2, respectively. With the aid of a plexiglass clamp and pressure monitored infusion system, each type of weld was tested six times to determine the intraluminal hydrostatic pressure required to burst the welded seam 1 minute after completing the weld. For the welds made with 107.1, 160.7, and 214.3 J/cm2 in both lasing modes, the mean bursting pressure was 40.7 mmHg (SD +/- 24.9) with no statistically significant difference in weld strengths at these energy densities. There was also no difference between continuous and pulsating delivery methods. However, the energy density of 53.6 J/cm2 in either method produced a mean bursting pressure significantly lower than those produced by the higher energy densities tested and below the estimated basal ileal intraluminal pressure of approximately 9 mmHg. Since 107.1 J/cm2 energy density caused the minimal gross tissue changes while producing an equally strong bond and since continuous is faster than pulsating, 500 mW of continuous delivery was considered the optimal setting for the CO2 laser welding of rabbit ileum.     

Primary closure of choledochotomy using CO2 laser: Comparison with suture closure

This study was designed to compare laser welding to suture closure of the common bile duct (CBD). A 12 mm linear choledochotomy was closed in 12 mongrel dogs using tissue welding lowenergy CO₂ laser. Tissue welding was accomplished at 5.0 w/cm² for 120 sec. Twelve similar mongrel dogs (control) were treated with CBD closure using 5/0 Vicryl (polyglactin 910, Ethicon, Inc., Somerville, NJ) interrupted simple stitches. All animals were sacrificed at six weeks. Gross and histologic evaluation of the choledochotomy site were performed. There were no statistical differences in parameters of comparison in the two groups. These parameters were pre- and post-treatment measurements of liver function tests, stenosis, and dehiscence. However, it must be noted that there was a 33% (4/12) incidence of dehiscence and death in the CO₂ laser welded choledochorrhaphy. This result, although not statistically significant, is clinically significant. We conclude that the tensile strength of CO₂ laser welded CBDs must be optimized and that these results are preliminary and still unreliable to recommend for clinical adaptability. © 1993 Wiley-Liss, Inc.     

CO2 and Nd:YAG laser systems in microsurgical venous anastomoses

Summary A comparative study was undertaken in 81 rats to investigate a CO₂ and Nd:YAG laser system for laserwelded anastomosis of the femoral vein. Conventionally sutured anastomoses (CMSA) served as controls. Laserwelded anastomosis (LAMA) was easier and could be performed 30% faster than CMSA. Postoperative investigations included patency tests, postmortem examinations and light and electron microscopy. Aneurysms were not seen. Foreign-body reaction was more pronounced in CMSA. Patency rates for CO₂-LAMA and CMSA were equal, whereas Nd:YAG-LAMA resulted in significantly higher rate of early postoperative thrombosis (P<0.01). Because of its physical properties, the CO₂-laser system seems to be better suited for laser welding of delicate structures such as the rat femoral vein.     

Low-energy CO2 laser intestinal anastomosis: an experimental study

Intestinal anastomosis was performed in 17 Wistar rats via tissue welding by the low-energy CO2 laser. The postoperative course in the animals studied was uneventful. The integrity of the anastomosis was investigated manometrically, immediately upon completion of the anastomosis as well as 20 days later. Ten additional Wistar rats served as controls in which conventional interrupted one-layer anastomosis was performed. The results show a significant superiority of the intestinal anastomoses that were constructed by means of laser tissue welding. The time to complete the anastomosis was also significantly shorter when laser rather than manual suturing was used. Serial histological examinations for up to 90 days following surgery revealed complete healing and epithelization of the anastomotic site.     

CO2 laser and suture in splenic parenchyma: an experimental study

Hemisplenectomy was performed with the scalpel in 12 mongrel dogs. The blood vessels of the splenic pedicle were temporarily clamped. In a six-dog group, hemostasis was obtained by CO2 laser and residual bleeding was controlled by sutures. In the other six dogs, group hemostasis was performed only by sutures. The surgical procedure was free of mortality. No hematological changes were observed in both groups. Histological studies revealed a better hemostatic effect and intensive necrosis of the splenic parenchyma in the lasered group compared with the sutured group.     

Laser and suture anastomosis: passive compliance and active force production.

One carotid from each dog underwent a laser anastomosis and the other carotid an interrupted suture repair. One or eight weeks later (n greater than or equal to 4 dogs/time period); four rings (1 mm in length) containing the laser or suture anastomosis or the normal artery (two/dog) were removed. Using a photoelectric force transducer and lever system, the ring was stretched in increments and passive force measured. At each length, the arterial muscle was stimulated and active force measured. The mean laser and control passive length/tension (L/T) curves were not different (P greater than 0.05), but the suture curve was shifted downward (P less than 0.05). The mean laser and suture active L/T curves were similar at 1 week (greater than 0.05) and lower than the control curve (P less than 0.04). At 8 weeks, the laser-repaired vessels produced an active force similar to control muscle (P greater than 0.05) but the suture repairs could not generate this active force (P less than 0.05). These data suggest that the laser repair and normal artery are more mechanically compatible than the suture repair as studied by this method.     

Comparative study of suture and laser-assisted anastomoses in rat sciatic nerves

Conventional suture repair of peripheral nerves results in a fibrotic reaction that is detrimental to nerve regeneration. As an alternative procedure known as "laser-assisted" repair, a laser can be used, along with a reduced number of sutures, to reanastomose served peripheral nerves. To explore the long-term implications of this technique, the right sciatic nerves of Sprague-Dawley rats were surgically cut and reanastomosed either by means of four epineurial sutures or two epineurial sutures and CO2 laser welds. Tensile strength, electrophysiology, histology, and functional studies were performed up to 11 months postoperatively. Tensile strength measurements indicate no long-term disadvantage with the laser-assisted technique, although the short-term tensile strength is lower than with conventional suture repair. The conduction velocities of the repaired nerves were similar for both techniques; however, laser-assisted repaired nerves were found to have lower stimulation thresholds and reduced branching compared to the suture repaired nerves. The measured functional recovery was similar for both repair techniques.     

The CO2 laser as an ideal microsurgical tool

The CO2 laser was used as a multipurpose microsurgical tool. It effectively evacuated cysts, vaporized tumors, coagulated fine blood vessels, abraded and flattened scars and rough tissue, and separated the epidermis from the dermis. Focused and defocused modes were applied to various lesions ranging from cysts to freckles. CO2 laser microsurgery differs from previous methods in that extremely fine and controlled therapy can be conducted with minimal damage to surrounding tissues and organs. Theories, techniques, and several case reports are described.     

Microvascular anastomosis using the milliwatt CO2 laser

The milliwatt CO2 laser was used to anastomose small vessels in a rat femoral artery model. The technique requires multiple brief applications of 60-70 mW after placement of three equidistant 10-0 nylon stay sutures. The vessel histology is described immediately and 1, 3, 7, and 21 days after the procedure. The laser effects tissue bonding through changes in the collagen of the adventitia and media. Subsequent healing consists of new collagen deposition in the adventitia and reendothelialization of the intima associated with neointimal proliferation at 3 weeks.     

Determination of efficient parameters for argon laser-assisted anastomoses in rats: Macroscopic,thermal, and histological evaluation

The aim of this study was to determine efficient parameters for an argon laser (spot diameter = 200 μm) to obtain and reproduce vessel anastomoses. It was performed in two groups of Wistar rats. In the first group (89 Laser impacts on 10 carotids), the fluence was continuously adjusted from 30 to 3,000 J/cm² in order to determine efficient sets of parameters (power from 90–200 mW, pulse duration from 0.1 to 5 seconds, pulsed or continuous mode). In the second group, 30 end-to-end carotid anastomoses were performed. The results were evaluated by macroscopic thermal, and histological studies. The second group proved the efficiency of the selected parameters. Vessel welding was obtained with 100 mW, 3 seconds, continuous mode (fluence = 950 J/cm², irradiance = 320 W/cm²) for a mean temperature of 77°C corresponding to collagen denaturation. In the second group the patency rate was 93% (28/30) with three pseudo-aneurisms and two thromboses. Histological studies noted slight modifications of the media. © 1994 Wiley-Liss, Inc.     

CO2 lasers: Beam patterns in relation to surgical use

According to surgeons operating with a variety of CO₂ lasers available at the National Cancer Institute of Milan (Coherent, Sharplan, Valfivre), these lasers have different cutting and coagulation properties. To identify what physical parameters might corroborate the subjective impression of the surgeons, a comparative study of the crater forms in perspex samples was performed. Perspex was chosen for its thermal properties (in fact, its thermal conductivity and diffusivity are similar to those of organic tissue) and because it allowed good visualization and measurement of crater characteristics. Depth of penetration, crater diameter, and extension of thermal damage were measured against power, focal length, and exposure time for each CO₂ laser model. These results can be used as an index of behaviour of different surgical lasers. It appears that for fully characterizing the interaction of surgical lasers with the sample, it is necessary to specify either power, focal length, exposure time, or beam mode.     

高频电刀、CO2 激光及手术切除精细缝合治疗皮肤色素痣的效果比较

目的 比较高频电刀、CO2激光及手术切除精细缝合3种治疗方式在皮肤色素痣患者中的应用效果。方法 选取旬阳市人民医院皮肤科2019年7月-2022年7月收治的360例皮肤色素痣患者为研究对象,根据治疗方法不同分为A组（n =113）、B组（n =120）、C组（n =127）。A组接受高频电刀治疗,B组接受CO2激光治疗,C组接受手术切除精细缝合治疗,比较三组临床疗效及不良反应发生情况。结果 C组治疗总有效率为97.64%,高于A组的82.30%,B组的85.83%,差异有统计学意义（P ＜0.05）;C组不良反应发生率为1.57%,低于A组的12.39%,B组的10.00%,差异有统计学意义（P ＜0.05）。结论 高频电刀、CO2激光及手术切除精细缝合治疗皮肤色素痣的效果均良好,但相比于高频电刀、CO2激光治疗,手术切除精细缝合治疗的有效性及安全性更佳,可作为临床治疗皮肤色素痣的首选。     

Laser-assisted microvascular anastomosis using CO2 and KTP/532 lasers.

The milliwatt carbon dioxide (CO2) laser has been shown to be an effective device for performing laser-assisted microvascular anastomosis (LAMA) with consistently high patency rates, minimal tissue disruption, and rapid surgical time as well as the potential for reduced inflammation due to fewer foreign bodies (sutures) in the wound. The purpose of this investigation was to determine the feasibility of using the potassium titanyl phosphate (KTP) laser to perform LAMA and to compare it to CO2 LAMA in both arteries and veins. Patency rates, inflammatory response, and course of healing were evaluated through histological analysis. Twenty-eight rats were divided into two groups, which underwent either CO2 or KTP LAMA and then were sacrificed at 3 days, and 1, 2, 4, 8, and 12 weeks postoperatively. Patency rates for arteries and veins were comparable for both wavelengths (CO2: 100% for arteries, 93% for veins; KTP: 93% for arteries, 93% for veins). Histological grading of inflammation and fibrosis showed no significant difference between the two groups. This study demonstrated the efficacy of using the KTP/532 laser in performing LAMA. We found the KTP and CO2 LAMA to have comparable patterns of tissue damage and course of healing. Although this experiment did not investigate the mechanism(s) of tissue welding, our results suggest that successful LAMA may be independent of wavelength.     

Comparison of stationary and dynamic fractional CO2 laser modalities of large burns treatment: Experimental laboratory model

ObjectivesTo experimentally compare two fractional ablative CO₂ laser handpieces intended for the treatment of large area burn scars. Each handpiece coverage rate, depth of penetration and application time were measured and compared in a simulation model of large area burns scars using a dynamic/roller handpiece (small footprint) and a stationary/stamping handpiece (large footprint).MethodsA 30 W fractional ablative CO₂ laser was applied using 2 different handpieces and footprints on a A4 size paper stack. The handpieces were a stationary (stamping) handpiece with 7 × 7 (49 pixels/square shape) and dynamic (roller) handpiece with 7 × 1 (7 pixels/single row shape). For both handpieces the laser settings were fixed at "High" power (30 W), providing an energy level of 100 mJ/pixel. Both handpieces were applied perpendicular to the surface, with the process repeated for the dynamic handpiece with an angled operation. The depth of laser penetration was assessed by the number of pages of paper having visible holes and burn area coverage time measured under each handpiece/condition.ResultsThe application time was faster and the penetration deeper for the dynamic handpiece compared to the stationary handpiece in both the perpendicular and angled conditions. This study has practical implications for lasers operators to improve time efficacy in large area scars with improved clinical endpoints.ConclusionThe fractional ablative dynamic handpiece demonstrated superior application efficiency compared to the stationary handpiece in the simulated treatment of large surface area burn scars, reducing treatment time with improved depth of penetration.     

食管癌切除术颈部机械吻合与手工吻合的疗效分析

目的 评价机械吻合与手工吻合在食管癌切除术颈部吻合中的应用价值.方法 本研究回顾性分析2010年1月至2012年1月四川省肿瘤医院收治的187例食管癌患者的临床资料,根据行食管癌切除术后颈部吻合的方式不同分为机械吻合组(98例)和手工吻合组(89例),比较两组患者吻合时间、总手术时间、术后开始进食时间、住院时间、术后并发症发生率及食管残端癌阳性率的差异,计量资料采用t检验,计数资料采用x2检验或Fisher确切概率法.结果 机械吻合组患者吻合时间、总手术时间、术后开始进食时间及住院时间分别为(7.8±1.4)min、(227±60) min、(6.3±0.9)d、(14±4)d,短于手工吻合组的(28.5±2.3) min、(301±81) min、(8.4±1.0)d、(22±9)d,两组比较,差异有统计学意义(t=75.44,7.14,7.71,7.41,P＜0.05);机械吻合组患者术后吻合口瘘发生率为1％ (1/98),低于手工吻合组的8％(7/89),两组比较,差异有统计学意义(P＜0.05);两组吻合口狭窄发生率分别为5％ (5/98)和7％ (6/89),两组比较,差异无统计学意义(P＞0.05);机械吻合组无食管残端癌,手工吻合组食管残端癌阳性率为4％(4/89),两组比较,差异有统计学意义(P＜0.05).结论 机械吻合在食管癌颈部吻合中不仅能缩短吻合时间、总手术时间及住院时间,而且能降低吻合口瘘发生率和食管残端癌阳性率.     

Comparison of laser vascular welding,interrupted sutures,and continuous sutures in growing vascular anastomoses

Background and Objectives: The argon laser-assisted vascular anastomosis may solve the problems of conventional sutured anastomosis, such as vascular stenosis and arrest of growth owing to a foreign-body reaction to suture material. Study Design/Materials and Methods: Twelve argon laser-assisted vascular anastomoses, seven conventional anastomoses with interrupted sutures, and five conventional anastomoses with continuous sutures were performed in 12 young mongrel dogs. Results: Five months later, the external diameter at the anastomosis had increased 70.5% in the laser group, 67.0% in the interrupted suture group, and 22.9% in the continuous suture group. Histological examination of the laser-assisted anastomoses showed almost complete healing, with no granulomatous response around the anastomotic site. In the interrupted suture group, marked scaring and foreign body reactions were observed on the vessel wall at the site of the anastomosis. The continuous suture group showed more remarkable disorientation of the vascular layer and intimal hyperplasia than the interrupted suture group. Conclusion: Vascular anastomosis using the argon laser offers advantages over the conventional procedure in growing vessels.     

Hysteroscope for CO2 laser application

Endoscopic laser surgery is becoming more common with the development of suitable instruments. A hysteroscope designed for use with a Sharplan CO₂ laser is described in detail. The method of application, results of preliminary experience, and possible indications are discussed.     

Investigation of carcinogenic effects of in Vitro Argon and CO2 laser exposure of fibroblasts

Mouse heteroploid fibroblasts were grown nine future generations in vitro tissue culture. The cells were exposed to argon laser, CO₂ laser, and x-ray. Results of scoring for mangnant transformation foci were tabulated and compared. Lasers did not produce a significant malignant transformation. Clinical laser use is reviewed and histology as well as long-term clinical experience confirms the safety of lasers.     

膝关节置换术中可吸收倒刺缝线与常规可吸收缝线缝合切口的效果比较

目的比较初次全膝关节置换术(total knee arthroplasty,TKA)中可吸收倒刺缝线与常规可吸收缝线缝合切口的临床效果。方法本研究回顾性地选取2017年1月至2018年12月我科收治的80例TKA病人为研究对象,2017年1～12月使用常规可吸收缝线间断缝合关节囊的40例病人纳入对照组,2018年1～12月采用可吸收倒刺缝线连续缝合关节囊的40例病人纳入观察组,比较两组的切口缝合时间、手术时间、拆线时间、住院时间和术后切口并发症发生率等指标的差异,收集两组术后切口疼痛、肿胀、活动度等一般情况及Lysholm膝关节功能评分。结果观察组的切口缝合时间和手术时间分别为(8.02±2.15)min、(65.05±9.15)min,明显少于对照组的(20.45±2.65)min、(94.45±5.28)min,两组相比,差异均有统计学意义(P均<0.05),但两组病人的拆线时间、住院时间比较,差异均无统计学意义(P均>0.05)。观察组的切口总并发症发生率、轻微并发症发生率和严重并发症发生率分别为17.5%、15.0%、2.5%,对照组分别为7.5%、7.5%、0,两...