激光微孔脱细胞真皮基质生物力学测试

目的：研究激光微孔脱细胞基质的生物力学性质变化,制作合适规格的脱细胞基质。方法：对不同间距的脱细胞真皮基质进行应力-应变和应力-松弛实验等检测,确定最佳孔径的脱细胞真皮基质。结果：确定350μm间距的脱细胞真皮基质有良好的生物力学性能。结论：超脉冲CO2激光可以对脱细胞真皮基质进行精细的微加工,脱细胞真皮基质适用于构建组织工程支架。     

超脉冲CO2激光联合强脉冲光治疗面部瘢痕

目的：观察超脉冲CO2激光联合强脉冲光治疗面部瘢痕的效果。方法：对50例面部瘢痕患者,采用超脉冲CO2激光和强脉冲光联合治疗6次。治疗间隔均为1个月。首先使用超脉冲CO2激光磨削,能量100～200mJ／脉冲,频率10～20脉冲／min。然后使用585nm强脉冲光治疗,脉宽2．5～15ms,能量密度25～35J／cm^2。结果：治疗结束后随访3～6个月,显效者33例,有效者14例,无效者3例。主要并发症为短暂红斑、色素沉着。结论：超脉冲CO2激光与585nm强脉冲光联合治疗面部瘢痕,具有较好的疗效,有操作准确、快捷、损伤小、术后恢复快、并发症少等优点。     

超脉冲CO2激光眼袋整复术120例分析

目的：总结分析超脉冲CO2激光用于眼袋整复术的临床疗效。方法：用超脉冲CO2激光对120例不同类型的眼袋患者采取经结膜入路或经皮肤入路分别进行眼袋整复术。结果：超脉冲CO2激光眼袋整复术术后满意率达99．2％。结论：用超脉冲CO2激光进行眼袋整复术可提高疗效，减少并发症的发生。     

皮肤肿瘤及其他皮肤病的激光治疗--激光美容系列讲座十

新型超脉冲CO2激光和铒激光等可对病变组织进行瞬间气化，使病变组织逐层破坏、消除而达到治疗目的。其作用深度可精确控制，且操作简便快速、创面出血少、视野清晰。由于新型激光的脉冲持续时间小于皮肤组织的热弛豫时间，因而对周围组织的热损伤微小，术后反应小、瘢痕发生率极低。超脉冲CO2激光和铒激光等已成为治疗一些以局部增生     

碳化二亚胺交联犬颈总动脉脱细胞基质的组织相容性初步研究

目的应用碳化二亚胺交联同种异体的犬颈总动脉脱细胞基质，对其进行组织相容性评价。方法应用多步骤除垢剂-胰酶作用制备犬颈总动脉脱细胞基质，按脱细胞基质与碳化二亚胺质量比1：1和1：2制备不同交联程度的脱细胞基质。通过体外降解率，细胞毒性MTT实验和大鼠皮下埋置实验对交联效果和组织相容性进行评价。结果经碳化二亚胺交联的脱细胞基质形态上无明显变化，HE染色纤维排列规则无断裂。0．1％Ⅱ型胶原酶作用下，交联的脱细胞基质的降解率较单纯脱细胞基质显著降低，交联程度高的脱细胞基质较交联程度低的脱细胞基质降解率低。细胞毒性MTT结果显示碳化二亚胺交联的脱细胞基质细胞毒性分级为0-1级，无细胞毒性。大鼠皮下埋置实验显示交联的脱细胞基质抵抗组织酶降解的能力显著提高，同时免疫反应减轻。交联程度高，效果越明显。结论碳化二亚胺交联的脱细胞基质具有良好的组织相容性和抗组织酶解能力，作为血管移植物和组织工程化血管的支架材料有广阔的应用前景。     

软骨脱细胞基质复合脂肪源性干细胞构建软骨组织的实验研究

[目的] 探讨软骨脱细胞基质支架材料的制备,及其体外复合脂肪源性干细胞构建软骨组织的技术方法.[方法] 成年新西兰大白兔脂肪源性干细胞获得,培养,扩增.成年新西兰大白兔新鲜软骨,低温冻干12 h,后经曲拉通、DNA、RNA酶等处理制备成为软骨脱细胞基质支架材料,终浓度为2×107/L的脂肪干细胞种植于软骨脱细胞基质中于软骨细胞方向诱导培养基中培养2周,构建软骨组织.新鲜制备的软骨脱细胞基质及构建的软骨组织分别行组织学、免疫组织化学及透射电镜检测.[结果] 实验制备的软骨脱细胞基质支架材料内无细胞结构存在,仅残留空白软骨陷窝.具有合适的孔隙率和孔径大小;复合脂肪源性干细胞后细胞向材料内部迁移,粘附,生长良好.部分载体内细胞Ⅱ型胶原免疫组化染色阳性.[结论] 软骨脱细胞基质可作为支架材料应用于软骨组织工程,复合脂肪源性干细胞培养可成功构建软骨组织.     

小肠黏膜脱细胞基质与牛心包脱细胞基质修复前尿道狭窄疗效比较

目的:比较小肠黏膜脱细胞基质与牛心包脱细胞基质在治疗前尿道狭窄的疗效。方法:分析我院2013~2016年采用小肠黏膜脱细胞基质与和牛心包脱细胞基质治疗共30例前尿道狭窄患者的临床资料。其中应用小肠黏膜脱细胞基质的16例,应用牛心包脱细胞基质的14例。比较2种不同材料修复前尿道狭窄术后并发症的发生率及手术成功率。结果:手术均顺利完成,术后定期随访复查显示采用小肠黏膜脱细胞基质16例中术后未出现尿路感染、排斥反应等并发症,最大尿流率15.6~45.0ml/s,平均尿流率27.1ml/s。采用牛心包脱细胞基质14例中,术后6例出现尿路感染,其中1例并发排斥反应,最大尿流率7.6~45.1 ml/s,平均尿流率19.5ml/s。结论:与牛心包脱细胞基质比较,小肠黏膜脱细胞基质在治疗前尿道狭窄中具有疗效好,术后感染率、排斥发生率低等优点。     

超脉冲CO2激光在睑袋修复术中的应用

目的：评价超脉冲CO2激光应用于睑袋修复术中的临床效果。方法：选择116例睑袋患者,68例采用超脉冲CO2激光辅助行睑袋修复术,48例行传统方法手术,比较两组术中出血量、手术时间、术后瘀血、肿胀消退时间、下睑外翻、切口瘢痕情况。结果：采用超脉冲CO2激光辅助行睑袋修复术组术中出血少、手术历时短、术后瘀血轻、肿胀消退快,两组结果比较差异具有统计学意义（P〈0.05）。两组在切口瘢痕方面无明显差别,均无下睑外翻。结论：应用超脉冲CO2激光行睑袋修复术是一种安全有效、操作便捷的方法,可以减少并发症。     

Ultrapulse 5000“C”激光用于眼袋成形术

目的 :观察新型超脉冲CO2 激光用于眼袋成形手术的结果。方法 :选择脂肪疝型眼袋患者 ,用新型激光行结膜囊内切口眼袋成形手术。结果 :眼袋成形手术共 10 7例 ,均一次手术成功 ,获得满意的效果。结论 :超脉冲CO2 激光用于眼袋成形术方便、快捷、出血少、周围组织热损伤小、无焦痂形成及伤口延迟愈合等并发症 ,具有普通手术刀或传统激光不可比拟的优点     

人包皮脱细胞基质组织工程化尿道的可行性研究

目的:为人包皮脱细胞基质作为尿道组织工程修复材料提供依据。方法:制备人包皮脱细胞基质,对其进行组织学观察、细胞毒性以及体内实验,检验其作为尿道材料的安全性和组织相容性。结果:制备的人包皮脱细胞基质,细胞去除完全,用原代包皮上皮细胞测定其细胞毒性,结果显示细胞相对增值率在75%～99%之间,细胞毒性为1级,符合国家标准,回植体内后,随着时间的延长,人包皮脱细胞基质与尿路上皮细胞结合完好,正常尿道复层结构层次逐步恢复。结论:人包皮脱细胞基质抗原性低,相容性好,可以作为组织工程尿道的支架材料。     

Reduction in lateral thermal damage using heat-conducting templates: a comparison of continuous wave and pulsed CO2 lasers

BACKGROUND AND OBJECTIVES: The advantages of the continuous wave (c.w.) CO(2) laser are offset by the delay in laser wound healing secondary to thermal damage. We have developed novel heat-conducting templates to reduce laser thermal damage. Because shortened pulse durations also decrease thermal damage, we tested the effectiveness of heat-conducting templates with a c.w. CO(2) clinical laser and a short-pulsed CO(2) laser to determine the best method and mechanism to minimize thermal damage. STUDY DESIGN/MATERIALS AND METHODS: Comparison of 0.2-second shuttered c.w. and 5-microsecond pulsed CO(2) lasers were made by doing incisions on 150 tissue samples from reduction mammoplasties and abdominoplasties. Copper, aluminum, glass, and Plexiglass heat-conducting templates were tested against no template (air) with both lasers. Histological samples were evaluated using computerized morphometrics analysis. RESULTS: Statistically significant reductions in lateral thermal damage were seen with the copper (50%) and aluminum (39%) templates used with the c.w. CO(2) laser. Only the copper template (39%) significantly reduced thermal damage when used with the pulsed CO(2) laser. Less thermal damage was seen using the pulsed CO(2) laser compared to the c.w. CO(2) laser with each template. CONCLUSIONS: Heat-conducting templates significantly reduced the amount of lateral thermal damage when used with the c.w. CO(2) laser (copper and aluminum) and short-pulsed CO(2) laser (copper). The c.w. CO(2) laser with the copper template compared favorably to the short-pulsed CO(2) laser without a template. Therefore, both heat conductive templates and short-pulse structure provide successful methods for reducing lateral thermal damage, and a combination of the two appears to provide optimal results.     

Laser assisted urethral closure in the rat: comparison of CO2 and Neodymium-YAG laser techniques

In 65 male rats a comparative study was undertaken to investigate a Neodymium-YAG and CO2 laser system for the microsurgical repair of longitudinal incisions of the rat urethra. Postoperative investigations included patency tests, necropsy and light microscopy. Use of the laser systems did not reduce operation time. The highest rate of postoperative strictures (90%), urethral fistulas (30%), urinomas (20%) and postoperative deaths (70%) was seen in the Neodymium-YAG laser group. CO2 laser repair was almost as efficacious as microsuture repair, except for a higher rate of urethral fistulas resulting from the initially weak laser weld. Based on these findings, the Neodymium-YAG laser seems unsuitable for urethral repair. Further studies in larger animals are warranted using a CO2 laser in combination with postoperative cystostomy for urinary diversion in order to avoid fistulas in the early postoperative period.     

Wound healing and collagen thermal damage in 7.5-microsec pulsed CO(2) laser skin incisions

BACKGROUND AND OBJECTIVE: Wound-healing delays caused by lateral thermal damage to tissue remain a drawback of CO(2) surgical lasers. This study compares the thermal damage and wound-healing properties of a 7.5-micros pulsed CO(2) laser with scalpel and continuous wave (CW) CO(2) laser incisions. STUDY DESIGN/MATERIALS AND METHODS: We created incisions on the dorsal pelts of rats with a 7.5-micros pulsed CO(2) laser at 5-, 10-, or 15-Hz repetition rate, a conventional CW laser, or scalpel. Animals were euthanized at postoperative days 3, 7, 14, 21, and 80. Tissue was harvested and analyzed histologically and for wound tensile strength. In addition, tissue was harvested acutely and analyzed for acute thermal injury lateral to the incisions. RESULTS: Incisions made with the pulsed laser had significantly higher tensile strength and histologic rankings than did CW laser incisions at days 3-21, producing 118 microm of thermal damage to tissue as compared with 333 microm for CW laser. Pulsed laser incisions were not statistically different than scalpel incisions at days 3-14 of healing. Mathematical modeling showed the pulsed laser to produce a wound healing delay of 1.0 day by tensiometry and 1.9 days by histology, compared with 3.2 days by tensiometry and 6.0 days by histology for CW laser. There were no significant differences in wound healing when the pulsed laser was used at repetition rates of 5-15 Hz. CONCLUSIONS: Using a 7.5-micros pulse duration, CO(2) laser incisions healed at a rate similar to scalpel incisions and reduced the wound-healing delay seen with typical surgical CO(2) lasers.     

A Comparative Clinical and Histologic Study of Hair Transplantation Using Er:YAG, Er:YAG/CO2, and Standard Punch Techniques

BACKGROUND: This study compares the effects of Er:YAG laser alone, Er:YAG/CO2 laser at 5 W (low power), Er:YAG/CO2 at 10 W (high power), and standard punch techniques in 10 men with androgenetic alopecia. OBJECTIVE: To study the clinical and histologic features of hair transplantation with recipient graft defects created by a new hybrid Er:YAG and CO2 laser. METHODS: Ten male patients (mean age 34 y) with Norwood IV-VI androgenetic alopecia had hair replacement surgery with the recipient sites divided into four quadrants comparing cold stell, erbium, combined erbium low-power CO2, and combined erbium high-power CO2 technologies. Hair growth, intraoperative procedure, lateral thermal damage, and patient satisfaction were compared, utilizing each of the four stated technologies. RESULTS: The addition of CO2 laser at both low and high power settings resulted in improved hemostasis when compared with standard punch or Er:YAG laser alone. The mean hair counts were similar for the Er:YAG laser, Er:YAG/CO2 (5 W) laser, and standard punch at both 3 and 6 months after treatment. Lateral thermal damage was not significantly increased by the addition of low-power CO2 to Er:YAG. The addition of high-power CO2 (10 W) laser resulted in slightly lower mean hair counts at 3 months, but significantly decreased at 6 months (P =.05). Also, high-power CO2 laser caused significantly increased lateral damage. There were no detectable differences in hsp70 expression among the groups. CONCLUSION: The addition of 5 W CO2 laser to Er:YAG laser results in better hemostasis than Er:YAG laser alone, while not significantly diminishing mean hair counts or inducing increased lateral thermal damage.     

Use of the CO2 laser in urology

The CO2 laser emits coherent light in the far infrared region with an extremely short extinction length. Energy absorption at the impact site is very intense and results in a surgical incision characterized by a zone of vaporization surrounded by a narrow zone of thermal necrosis and sublethal thermal injury. Infected epithelium can be ablated precisely to a shallow depth so that the papillomavirus is killed and rapid healing can occur. The CO2 laser is the treatment of choice for condylomata acuminata that are extensive or recurrent, are within the urethral meatus, or occur during pregnancy, a period during which cytotoxic drugs are contraindicated. With this technique virtually all patients with condylomata acuminata can be cured rapidly with minimal morbidity, complications, or risk of recurrence.     

Comparison of Er:YAG and 9.6-microm TE CO(2) lasers for ablation of skull tissue

BACKGROUND AND OBJECTIVE: Craniotomy by using a drill and saw frequently results in fragmentation of the skull plate. Lasers have the potential to remove the skull plate intact, simplifying the reconstructive surgery. STUDY DESIGN/MATERIALS AND METHODS: Transverse-excited CO(2) lasers operating at the peak absorption wavelength of bone (lambda = 9.6 microm) and with pulse durations of 5-8 microsec, approximately the thermal relaxation time in hard tissue, produced high ablation rates and minimal peripheral thermal damage. Both thick (2 mm) and thin (250 microm) bovine skull samples were perforated and the ablation rates calculated. Results were compared with Q-switched and free-running Er:YAG lasers (lambda = 2.94 microm, tau(p) = 0.5 microsec and 300 microsec). RESULTS: The CO(2) laser produced ablation rates of up to 60 and 15 microm per pulse for thin and thick sections, respectively, and perforated thin and thick sections with fluences of less than 1 J/cm(2) and 6 J/cm(2), respectively. There was no discernible thermal damage and no need for water irrigation during ablation. Pulse durations > or =20 microsec resulted in significant tissue charring, which increased with the pulse duration. Although the free-running Er:YAG laser produced ablation rates of up to 100 microm per pulse, fluences of 10 J/cm(2) and 30 J/cm(2) were required to perforate thin and thick samples, respectively, and peripheral thermal damage measured 25-40 microm. CONCLUSIONS: In summary, the novel 5- to 8-microsec pulse length of the TE CO(2) laser is long enough to avoid a marked reduction in the ablation rate due to plasma formation and short enough to avoid peripheral thermal damage through thermal diffusion during the laser pulse. Furthermore, in vivo animal studies with the TE CO(2) laser are warranted for potential clinical application in craniotomy and craniofacial procedures.     

Optimization of the Erbium:YAG laser for precise incision of ureteral and urethral tissues: in vitro and in vivo results

BACKGROUND AND OBJECTIVES: Tissue damage during endoscopic treatment of urethral and ureteral strictures may result in stricture recurrence. The Erbium:YAG laser ablates soft tissues with minimal peripheral damage and may be a promising alternative to cold knife and Holmium:YAG laser for precise incision of urological strictures. STUDY DESIGN/MATERIALS AND METHODS: Optimization of the Er:YAG laser was conducted using ex vivo porcine ureteral and canine urethral tissues. Preliminary in vivo studies were also performed in a laparoscopic porcine ureteral model with exposed ureter. Laser radiation with a wavelength of 2.94 microm, pulse lengths of 8, 70, and 220 microseconds, output energies of 2-35 mJ, fluences of 1-25 J/cm2, and pulse repetition rates of 5-30 Hz, was delivered through 250-microm and 425-microm core germanium oxide optical fibers in direct contact with tissue. RESULTS: Ex vivo perforation thresholds measured 2-4 J/cm2, with ablation rates of 50 microm/pulse at fluences of 6-11 J/cm2. In vivo perforation thresholds were approximately 1.8 J/cm2, with the ureter perforated in less than 20 pulses at fluences greater than 3.6 J/cm2. Peripheral thermal damage in tissue decreased from 30 to 60 microm to 10-20 microm as the laser pulse length decreased from 220 to 8 microseconds. Mechanical tissue damage was observed at the 8 microseconds pulse duration. CONCLUSIONS: The Er:YAG laser, operating at a pulse duration of approximately 70 microseconds, a fluence greater than approximately 4 J/cm2, and a repetition rate less than 20 Hz, is capable of rapidly incising urethral and ureteral tissues with minimal thermal and mechanical side-effects.     

Potential applications of the erbium:YAG laser in endourology.

The holmium:YAG laser has become the laser of choice in endourology because of its multiple applications in the fragmentation of kidney stones, incision of strictures, and coagulation of tumors. This paper describes the potential use of a new laser, the erbium:YAG laser, for applications in endourology. Recent studies suggest that the Er:YAG laser may be superior to the Ho:YAG laser for precise ablation of strictures with minimal peripheral thermal damage and for more efficient laser lithotripsy. The Er:YAG laser cuts urethral and ureteral tissues more precisely than does the Ho:YAG laser, leaving a residual peripheral thermal damage zone of 30 +/- 10 microm compared with 290 +/- 30 microm for the Ho:YAG laser. This result may be important in the treatment of strictures, where residual thermal damage may induce scarring and result in stricture recurrence. The Er:YAG laser may represent an alternative to the cold knife and Ho:YAG laser in applications where minimal mechanical and thermal insult to tissue is required.     

CO2 laser urethroplasty in the rabbit: a preclinical model.

Our previous work has shown that the CO2 laser can be successfully used in urethral reconstruction in a rat model. This new experiment investigates the use of the CO2 laser to perform a patch graft urethroplasty in the rabbit, as a preclinical model to its use in the repair of hypospadias in humans. Using sterile technique, a patch graft of preputial skin was welded in the repair of a standardized urethral defect in 10 rabbits. In another cohort, the same urethral defect was repaired using standard microsuture technique. In a control group the patch graft was placed with microsuture in a nonwatertight fashion. All animals were followed for 3 weeks. Histologic and radiologic analyses were done in a blinded fashion. Our study showed that CO2 laser repair, when compared to microsuture in urethral reconstruction, required 40% less operative time and produced better graft healing and less intraluminal scarring.     

Deep coagulation of dermal collagen with repetitive Er:YAG laser irradiation

BACKGROUND AND OBJECTIVE: Er:YAG lasers are known to effectively ablate human skin with minimal thermal damage to subjacent dermal tissue. We have investigated whether deep coagulation of dermal collagen, similar to that observed with the CO(2) laser, could be achieved with repetitive Er:YAG laser exposures. STUDY DESIGN/MATERIALS AND METHODS: Skin on the back of a Sprague-Dawley rat in vivo was irradiated with sequences of 1-10 Er:YAG laser pulses at a repetition rate of 10 or 33 Hz and single-pulse fluences from 0.8 to 1.4 J/cm(2). The resulting lesions were biopsied within 1 hour after laser exposure, and the histologic sections were examined by using optical microscopy. RESULTS: The depth of dermal collagen denaturation increases dramatically when 3-10 low-fluence Er:YAG laser pulses are stacked at a repetition rate of 10 or 33 Hz. CONCLUSION: Coagulation of dermal collagen deeper than 200 microm below the epidermal-dermal junction is feasible by using the appropriate settings of a repetitive Er:YAG laser.