支架置入治疗前列腺增生所致尿道狭窄

目的：探讨对前列腺增生症尿潴留患者采用X线电视监视下行后尿道内支架置入术的方法及其疗效。方法：应用国产自膨式镍钛记忆合金支架及推送器，通过逆行泛影葡胺尿道及膀胱造影，以后尿道对比剂断端或尿道狭窄处远端为前测点，膀胱颈部前列腺增生叶的最凸点为后测点，两点间距除以1．0一1．3为选用支架的长度。前列腺均匀增生型选用筒状支架；单叶增生型选用靠背型支架。支架后端平后测点为最佳位置，术后1、6、12和36个月复查支架位置、形态及尿潴留量。结果：通过32例患者的介入治疗，置入成功率100％，术中出血6例(18．8％)。1、6、12和36个月复查，未发现支架移位、尿失禁及膀胱结石等并发症，术后均自主排尿通畅。结论：通过尿道造影选用内支架长度，X线监视下内支架置入，定位准确，疗效可靠，创伤小，对不宜外科手术的前列腺增生伴尿潴留患者，可做为首选治疗方法。     

尿道前列腺段狭窄放射介入内支架置入术

前列腺增生造成尿道前列腺段狭窄引起老年人排尿困难，给老年人带来很大痛苦。临床对于部分病人的治疗有一定的限度。尿道前列腺段狭窄的内支架置入，能够解除部分病人的排尿困难。现将我院2003年9月—2004年12月收活尿道前列腺段狭窄35例尿道前列腺段狭窄的内支架置入术的体会介绍如下。     

食管内支架置入后的随访研究

目的食管狭窄置入金属支架后长期随访，观察其疗效和并发症。方法４３例食管狭窄放置了金属支架患者有较完整的随访资料。良性狭窄１４例，恶性狭窄２９例。置入Ｕｌｔｒｅｆｌｅｘ支架３２例，ＧｉａｎｔｕｒｃｏＺ型带膜支架４例，国产网状支架６例，Ｗａｌｓｔｅｎｔ支架１例。门诊随访行食管造影和内窥镜检查２７例，电话或信访１６例。结果１～３２个月随访观察，无支架移位。２４例死亡，术后生存时间１７天至２８个月，平均６．８个月。死亡原因：肿瘤广泛转移１９例，肺部感染２例，其他原因引起死亡３例。发生再狭窄１６例，为支架内或两端发生狭窄。肿瘤组织生长造成的狭窄４例，１２例为食管腔内组织过度增生，这类狭窄全部发生在置入支架后４～５个月。支架内狭窄５例，支架两端狭窄１１例，其中１０例为支架上端狭窄。１２例行再次球囊扩张或支架置入。结论肿瘤的生长，特别是粘膜和纤维组织增生是引起再狭窄的主要原因，支架上端狭窄更容易发生吞咽困难。由于再狭窄的发生率较高，对于良性食管狭窄的支架成型术应严格选择病例。     

犬肝内动脉覆膜支架置入的实验研究

目的从支架置入的成功率、贴壁性、支架内狭窄率及支架内皮化等诸方面探讨犬肝内动脉覆膜支架置入的可行性。方法成年毕格犬8只,全麻下采用介入技术在其肝右动脉/肝固有动脉内置入球囊扩张式可膨胀聚四氟乙烯(ePTFE)覆膜膜支架,置入后即刻及术后2、4和12周行DSA复查,观察支架置入过程及其造影表现、标本的组织病理学表现,对参数进行统计学分析。结果支架均输送到位并顺利置入8只犬肝右动脉/肝固有动脉;支架释放后贴壁性能良好,所隔绝的动脉分支未显影;以管腔丢失>50%为明显狭窄标准,2周复查时有2只犬出现支架内明显狭窄,12周复查时有3只犬出现支架内明显狭窄(3/8)。病理显示2只犬为血栓形成、1只犬为内膜增生所致;5只犬支架出现完全内皮化(标本3个不同取材部位均完全内皮化),3只犬支架内皮化不完全(标本3个取材部位至少有1处未内皮化);支架两端较中央部更易形成内皮化;支架置入前后,所有犬肝功能均未出现显著改变。结论球囊扩张式覆膜膜支架能够顺利置入犬肝动脉,并且具有良好的贴壁性,能形成完整的内皮化,不会对肝功能带来影响。覆膜支架的犬肝内动脉置入是可行的。     

新型网状自展式金属内支架的实验研究（血管造影,光镜及扫…

为了克服目前应用的自展式内支架的一些缺点，笔者研制了一种新型网状自展式金属内支架。本实验重点观察支架植入后的病理改变。实验动物为健康犬８只，导入支架１８个，部位包括上、下腔静脉，腹主动脉，髂总动、静脉；植入后间隔１个月造影复查，观察时间１～８个月，并对支架区血管行大体病理、光镜及扫描电镜检查。结果：１８个支架均成功地导入靶区，无并发症；造影复查未发现支架移位及植入区血管狭窄，支架跨越血管分支显影良     

大鼠食管支架置入术后再狭窄模型构建及观察

目的 探讨大鼠食管支架置入及术后食管良性增生性狭窄模型构建的可行性和安全性.方法 实验使用定制的自膨式金属直筒支架(直径5 mm,长15 mm),其中部两侧各有一外突倒刺用作固定,防止滑脱移位.12只健康Sprague-Dawley大鼠随机分成A组(空白对照组)和B组(支架置入组),每组6只;B组大鼠食管内置入支架,分别于置入即刻、1周、4周作食管造影.4周后处死所有大鼠,取A组正常食管组织及B组支架部位食管组织作大体形态、光镜等病理学分析.结果 B组食管内支架置人均获成功,术后即刻、1周、4周复查造影均未发现食管内支架移位,手术及随访期间无严重并发症发生.与A组相比,4周后B组复查造影显示支架段食管增生导致食管狭窄,取出支架部位食管段肉眼见管腔明显狭窄,光镜下呈典型良性增生样表现.结论 采用大鼠构建食管支架置入后再狭窄模型安全、可行,带倒刺食管支架能够明显降低支架置人后移位发生率.     

镍钛合金网状支架治疗高龄前列腺增生的疗效观察

前列腺增生是老年男性的常见病,随着人民生活水平的提高和寿命的延长,前列腺增生的发病率也随之升高。1980年Fabian首先介绍了金属螺旋尿道支架置人前列腺尿道治疗尿路梗阻。近年来采用形状记忆合金网状支架治疗高龄,高危或不愿意接受前列腺电切(TURP)手术的前列腺增生患者取得了良好的效果。我院自2002年10月～2004年6月对38例高龄前列腺增生患者采用网状支架前列腺尿道置入,取得了满意效果,现报告如下。     

西罗莫司涂层气管支架在气管狭窄动物模型中的应用

【摘要】目的:探讨西罗莫司涂层气管支架抑制气管狭窄动物模型肉芽组织增生的有效性。方法:选用2.5～3.0kg新西兰大耳白兔36只,分成对照组（n=18只）,置入普通镍钛合金裸支架,实验组（n=18只）,置入西罗莫司涂层镍钛合金裸支架;每组内根据处死时间分为1个月组、2个月组和3个月组,各6只。采用气管切开联合毛刷破坏粘膜法制作气管狭窄动物模型。镍钛合金裸支架36枚,其中18枚浸涂以PLGA为载体的西罗莫司涂层,并进行体外药物缓释实验。透视下行气管支架置入,分别于支架置入后的1个月、2个月和3个月复查胸部CT了解气管狭窄情况,并处死相应组别的兔子,于支架上下两端取标本行HE染色病理检查比较两组气管粘膜增生情况。结果：制作气管狭窄模型过程中1只死于麻醉过深,2只在模型制作后3d因严重气管粘膜充血水肿死亡,其余33只气管狭窄模型制作成功,补做3只均成功,狭窄程度50%～85%。所有气管狭窄模型均一次性成功置入气管支架。术后1个月、2个月和3个月复查胸部CT显示对照组支架上下缘均有不同程度的肉芽组织增生,以支架上缘为著,最狭窄处平均狭窄程度分别为（81.6±2.8）%、（66.4±1.6）%和（78.2±2.3）%。实验组肉芽组织增生明显较轻,最狭窄处平均狭窄程度分别为（61.68±2.3）%、（45.23±4.5）%和（50.97±3.8）%。处死实验兔于支架上下缘取标本行病理检查见药物涂层支架组纤维素增生和胶原蛋白沉积程度较轻。结论：西罗莫司涂层可有效抑制镍钛合金支架置入后的肉芽组织增生,降低支架置入后再狭窄程度。     

合并血栓形成Budd－Chiari综合征的介入治疗

目的：研究并有血栓形成Ｂｕｄｄ－Ｃｈｉａｒｉ综合征的介入治疗。材料与方法：３例为肝段下腔静脉阻塞并阻塞下方血栓形成。应用导丝对血栓行穿通试验，证实为软血栓后用手推法注入尿激酶溶栓，而后对其阻塞的下腔静脉行穿通术，球囊扩张及内支架置入。结果：３例溶栓及相应介入治疗成功，下腔静脉压力由术前的３．４１ｋＰａ，降至１．７５ｋＰａ。结论：对于软血栓行溶栓治疗后再对阻塞的下腔静脉行ＰＴＡ及内支架置入，可避免肺栓塞发生。对机化血栓直接行穿通术，ＰＴＡ及内支架置入。     

排尿法CT诊断前列腺增生的研究

目的：采用排尿法ＣＴ（ＭＣＴ）检查方法，评价增生的前列腺组织对尿道的压迫、对排尿功能的影响和膀胱的继发性改变。方法：将３２例患者分为二组：正常组１０例，增生组２２例。增生组又分为３个型，肿块型１４例，结节型３例，混合型５例。在注射造影剂后３０ｍｉｎ～１ｈ，进行排尿法ＣＴ检查。观察前列腺段尿道的形态改变及计算其截面积；记录排尿时间、排尿量；计算膀胱残余尿量及膀胱排尿指数；观察膀胱壁的形态改变。结果：正常前列腺段尿道有点圆形、椭圆形、圆形及三角形等数种形态，它们是不同排尿时相的表现。尿道后壁中央有精阜突出，尿道内口呈圆形。增生组表现为尿道受压，截面积变小和尿道移位、扭曲等，同时伴有排尿功能的改变和膀胱残余尿量的增加。肿块型增生时，尿道受压较严重，排尿时间明显延长。结节型增生对排尿时间影响不大。膀胱壁的继发改变有膀胱小梁形成及真性和／或假性憩室。结论：ＭＣＴ能揭示前列腺增生的病理过程——压迫尿道产生排尿不畅以及膀胱的继发病变，是一种较为理想的前列腺增生的检查方法     

X线监视下经尿道植入支架治疗高龄前列腺增生症

目的评价植入网状记忆合金支架治疗高龄前列腺增生症尿道狭窄的临床效果和可行性。方法47例患者,年龄72~93岁,平均78.3岁,排尿困难7~21年。1%利多卡因尿道黏膜麻醉,DSA引导下经尿道将支架放置在前列腺尿道最狭窄处。结果47例患者均一次治疗成功(100%),其中43例支架植入后立即自行排尿,排尿通畅。本组无1例出现尿道再狭窄和结石等情况,排尿通畅率100%。结论记忆合金网状支架治疗前列腺增生引起的排尿困难临床疗效显著,值得临床推广应用。     

Experimental study of the intraurethral placement of expandable metallic stents

Various types of Gianturco expandable metallic stents were implanted into the urethra of four dogs in order to evaluate the suitable expandability of the stents in urethra and also to determine the effect of the stents on the urethral wall. The stent of 1.5 cm in length and constructed of 0.010 inch round stainless steel wire with twelve zigzag bends showed the suitable expandability on the canine urethra compared to the other stents. The urethra remained patent and the inflammatory changes on the urethral wall were moderately noted. No hematuria or calcifications around the stents were noted in any dogs. The experimental data showed a potential clinical application.     

Renal cyst pseudoenhancement: evaluation with an anthropomorphic body CT phantom

PURPOSE: To evaluate the feasibility of using a retrievable urethral stent and to evaluate whether granulation tissue resolves after stent removal in a canine urethra. MATERIALS AND METHODS: Polyurethane-covered retrievable 0.10-mm-thick (n = 11) or 0.15-mm-thick (n = 10) nitinol wire stents were placed in the urethras of 20 dogs. In one dog, a second stent was placed in the urethra because of complete migration of the first stent into the urinary bladder. The stents were removed with retrieval hook wires 4 weeks (n = 10) and 8 weeks (n = 10) after placement. Fourteen dogs were sacrificed just after stent removal, and the other six dogs were sacrificed 2 weeks after stent removal. Information concerning procedure success, stent migration, and tissue response was obtained. RESULTS: Stent placement was technically successful in all dogs. Follow-up urethrograms showed partial (n = 4) or complete (n = 1) stent migration. Stent removal failed in two dogs due to partial or complete migration. Granulation tissue was observed at both ends of the stent in 17 dogs. Urethrograms and urethral specimens obtained 2 weeks after stent removal showed diminished granulation tissue and decreased thickness of the papillary projections of the epithelium compared with results obtained immediately after stent removal. CONCLUSION: Although some design modifications are necessary to reduce current complications, the polyurethane-covered retrievable nitinol stent seems feasible for use in the urethra. Stent-induced granulation tissue formation improved after stent removal.     

Tissue hyperplasia: influence of a paclitaxel-eluting covered stent--preliminary study in a canine urethral model

PURPOSE: To evaluate a paclitaxel-eluting covered stent in reduction of tissue hyperplasia after stent placement in a canine urethral model. MATERIALS AND METHODS: Procedures were performed in accordance with the National Institutes of Health guidelines for humane handling of animals; approval of the committee of animal research was obtained. Twenty paclitaxel-eluting polyurethane-covered stents (drug stents) and 20 polyurethane-covered stents (control stents) were placed alternately between the proximal and distal urethra in 20 male dogs. The dose of paclitaxel was approximately 1800 mug in each drug stent but absent in each control stent. Dogs were sacrificed either 4 (n = 10) or 8 (n = 10) weeks after stent placement. The percentage diameter of stenosis was assessed with follow-up retrograde urethrography and histologic findings obtained after sacrifice and compared between drug stents and control stents and between the proximal and the distal urethra. RESULTS: Two drug stents partially migrated during retrograde urethrography immediately after stent placement; they were removed and replaced with a second stent during the same procedure. There was a strong tendency toward a lower percentage diameter of stenosis and numeric mean values of the four histologic findings, which indicates less formation of tissue hyperplasia in the proximal urethra than in the distal urethra. In particular, thickness of the papillary projection denoting the entire thickness of hyperplastic reaction was significantly less in drug stents than in control stents in the proximal urethra in the 8-week group (P = .016, Mann-Whitney U test). CONCLUSION: Local delivery of paclitaxel via covered stents has the potential to reduce tissue hyperplasia secondary to stent placement in a canine urethral model. With stent placement, there are distinct differences of tissue hyperplasia between the proximal and distal urethra.     

Polydioxanone Biodegradable Stent Placement in a Canine Urethral Model: Analysis of Inflammatory Reaction and Biodegradation

PurposeTo investigate the inflammatory reaction and perform quantitative analysis of biodegradation after placement of a polydioxanone (PDO) biodegradable stent in a canine urethral model.Materials and MethodsPDO biodegradable stents were placed in the proximal and distal urethra of nine male mongrel dogs. The dogs were euthanized 4 weeks (group A; n = 3), 8 weeks (group B; n = 3), or 12 weeks (group C; n = 3) after stent placement. The luminal diameter of the stent-implanted urethra was assessed by follow-up retrograde urethrography, and histologic findings were obtained after the dogs were killed. Stents were removed after euthanasia, and their surface morphology and molecular weight were evaluated. Hematologic examination was performed to evaluate inflammatory reaction.ResultsStent placement was technically successful in all dogs. The average luminal diameter gradually decreased. The average number of epithelial layers (2.93 vs 4.42; P < .001), the average thickness of papillary projection (0.80 mm vs 1.28 mm; P < .001), and the average thickness of submucosal fibrosis (0.34 mm vs 0.49 mm ; P < .001) were significantly increased in group B versus group A. There were no significant differences between group B and group C. The average inflammatory cell infiltration did not differ significantly in the three groups. Molecular weight losses were 54% in group A and 84% in group B. In group C, PDO stents were completely decomposed.ConclusionsAn experimental study in a canine urethral model has demonstrated acceptable inflammatory reaction with gradually increasing granulation tissue but no luminal obstruction within 12 weeks.     

Is a flared stent effective for decreasing stent migration in canine prostatic urethra?

Background: Prostatic urethral stents are effective in relieving obstructions caused by benign prostatic hyperplasia (BPH). However, migration of these stents occurs frequently.

Purpose: To evaluate the efficacy of a flared stent for decreasing the migration rate in comparison with a straight stent in a canine prostatic urethral model.

Material and Methods: The flared stent (15 mm in diameter and 20 mm in length) was flared up to 19 mm at both ends to prevent migration. A straight stent with the same size was straight without flaring. Both stents were made of a nitinol wire filament and covered with an expanded polytetrafluoroethylene (ePTFE) membrane. The flared stent was inserted in the prostatic urethra of 10 dogs (group 1) and the straight stent in the prostatic urethra of 12 dogs (group 2). Follow-up retrograde urethrography (RUG) was performed 1, 4, and 8 weeks after stent placement. Fisher's exact test was used to compare the migration rate between the two groups. When stent migration occurred during the follow-up period, the same type of stent was inserted again.

Results: Three of 10 (30.0%) flared stents migrated into the urinary bladder between 1 week and 4 weeks after placement. Seven of 12 (58.3%) straight stents migrated into the urinary bladder 1 (n = 3), 4 (n = 1), and 8 (n = 3) weeks following placement. The flared stent group showed lower migration rate than the straight stent group, but the migration rate did not reach statistical significance (P = 0.231). After the second stent placement, one of three (33.3%) flared stents migrated again after 4 weeks and two of seven straight stents (28.6%) after 1 week.

Conclusion: Although the migration rate was not statistically significant, the flaring of the stent seemed to reduce the migration rate in comparison with straight stents in a canine prostatic urethral model. However, the migration rate of the flared stent was still high, and further developments are required to decrease migration rate.     

食管自展型金属网状支架的实验研究

目的：研究食管长期植入支架的组织反应，评价自制支架的组织相容性。方法：将自制网状支架植入１４只家兔食管，进行为期２～２４周的实验观察。结果：１４只支架准确植入。与支架钢丝相接触的食管粘膜增生增厚而后逐渐变薄并接近正常，８～１２周粘膜覆盖支架，支架两端处食管粘膜损伤较重。支架钢丝未见腐蚀。发生合并症５例，４例与饮食有关。结论：该支架具有良好的组织相容性和耐腐性，并发症的发生与植入支架后的饮食密切相关     

Evaluation of the Effects of Temporary Covered Nitinol Stent Placement in the Prostatic Urethra: Short-Term Study in the Canine Model

Purpose To evaluate the effect of temporary stent placement on the canine prostatic urethra. Methods Retrievable PTFE-covered nitinol stents were placed in the prostatic urethras of 8 beagle dogs under fluoroscopic guidance. Retrograde urethrography was obtained before and after stenting. Retrograde urethrography and endoscopy were performed 1 and 2 months after deployment. The endoscopic degree of hyperplasia was rated on a scale of 0 to 4 (0 = absence, 4 = occlusion). On day 60, stents were removed and urethrography was performed immediately before euthanasia. Pathologic analysis was performed to determine the degree of glandular atrophy, periurethral fibrosis, and urethral dilation. Results Stent deployment was technically successful in 7 animals, and failed in 1 dog due to a narrow urethral lumen. Complete migration was seen in 2 animals at 1 month, and an additional stent was deployed. On day 30, endoscopy showed slight hyperplasia (grade 1) in 3 animals. On day 60, moderate hyperplasia (grade 2) was evidenced in 4 cases. No impairment of urinary flow was seen during follow-up. Retrieval was technically easy to perform, and was successful in all dogs. The major histologic findings were chronic inflammatory cell infiltrates; prostate glandular atrophy, with a mean value of 1.86 (SD 0.90); periurethral fibrosis, with a mean ratio of 29.37 (SD 10.41); and dilatation of the prostatic urethra, with a mean ratio of 6.75 (SD 3.22). Conclusion Temporary prostatic stent placement in dogs is safe and feasible, causing marked enlargement of the prostatic urethral lumen. Retrievable covered stents may therefore be an option for bladder outlet obstruction management in men.     

Flexible tantalum stents: Effects in the stenotic canine urethra

Purpose Evaluate the effects of flexible tantalum stents (Strecker) implanted into stenotic canine urethras.Methods Eight conditioned, adult, German shepherd dogs, weighing 30–40 kg, were used. Strictures were created surgically in the bulbar urethra just proximal to the os penis. Two months postsurgery, strictures were documented radiographically and then balloon dilated. Following dilatation, a single Strecker stent was placed across the stricture. Stents were 7 mm in expanded diameter and either 2 or 4 cm in length. Retrograde urethrography was performed immediately after stent placement and then biweekly for up to 12 months. Two dogs were sacrificed at 2, 4, 6, and 12 months post-stenting, and necropsy was performed. The urethra was excised, fixed, and examined by scanning electron and light microscopy.Results Clinical success was achieved without complications in all animals. Hyperplasia of the urothelium was noted 4–6 weeks after stent placement and was most pronounced at 4–6 months. Mucosal folds were found between the stent struts. Restenosis occurred at the distal end of the stent in one dog. Histological alterations were noted in the deeper layers of the urethral wall.Conclusion Strecker stents were well tolerated in all animals and seem useful for the treatment of urethral strictures.Presented at CIRSE Annual Meeting and Postgraduate Course, Budapest, June 20–24, 1993     

覆膜内支架在食管癌术后吻合口瘘中的应用

目的：观察覆膜内支架在食管癌术后吻合口瘘中的应用效果。方法：15例中、晚期食管癌术后3－21天出现吻合口瘘。瘘口直径0．8－2．1cm。将180cm长交换导丝经口送入胃内，沿导丝送入支架输送系统，将直径1．8cm的双喇叭覆聚氨脂膜的镍钛记忆合金食管内支架的中点置于瘘口平面，透视下缓慢释放支架，后撤出输送系统和导丝。结果：全部病例均一次放置成功，技术成功率为100％。13例患者一次堵瘘成功，患者在支架置入术后3－7天进半流质食物，15天后进普食，其余2例病情改善。结论：覆膜双喇叭记忆合金内支架为封堵食管癌术后吻合口瘘最有效的方法之一。