Three new experimental models of anterior urethral stricture in rabbits

BackgroundThis study describes and compares three surgical procedures for the construction of urethral stricture (US) models in rabbits.MethodsForty adult male rabbits were allocated to four groups: 36 rabbits were randomly assigned to three experimental groups, while the remaining 4 were assigned to a sham group. The penis was separated from the rectum. Then along the ventral midline, a longitudinal penile skin incision was made while ensuring that the urethral mucosa was intact and the muscular layer was not completely incised. In group 1 (n=12), ventral semi-circumferential mucosa electrocoagulation of a 1-cm length of the anterior urethra was performed until ulceration occurred. In group 2 (n=12), the ventral urethral mucosa was incised, and electrocoagulation of the dorsal semi-circumferential mucosa was performed. In group 3 (n=12), whole-circumferential mucosa electrocoagulation was performed. In group 4 (n=4), no special treatment was performed. Four weeks later, urethrography, urethroscopy, and histological evaluation were carried out.ResultsThe weights of the rabbits in the four groups were comparable. There was no significant difference between groups 2 and 3 with regard to operative time, but the operative time in these groups was significantly longer than that in group 1 (group 2 vs. group 1: P<0.05, group 3 vs. group 1: P<0.001). After the surgery, urinary fistula with infection occurred in one rabbit in group 1, and one rabbit died due to urethral atresia in group 3. According to the urethrography and urethroscopy findings, 9 out of 12 rabbits in group 1, 5 out of 12 rabbits in group 2, and 11 out of 11 rabbits in group 3 developed US, while no rabbits in the sham group developed US. Histopathological examination revealed injury to the urothelium, inflammatory infiltration, a decrease in the amount of blood vessels and smooth muscle fibers, and a decrease in the amount of collagen fibers.ConclusionsCompared with the semi-circumferential procedures, the whole-circumferential procedure had a higher success rate. Therefore, this procedure seems to have potential for the construction of long-segment rabbit US models.     

输尿管镜下尿道置管会师术治疗尿道断裂八例

目的探讨输尿管镜下行尿道置管会师术治疗尿道断裂的临床效果和使用价值。方法对2008年10月至2011年2月间经输尿管镜下行尿道置管会师术治疗尿道断裂的病例进行回顾性分析;输尿管镜下经尿道外或内口置入导丝至膀胱,再经导丝引导插入Foley导尿管牵引固定,引流尿液2～4周后拔管。结果 8例全部手术成功,7例经尿道外口置管,另1例经尿道内、外口双向置管。前尿道不完全断裂2例,后尿道完全断裂6例。手术时间10～45min。术后随访6～12个月,6例排尿通畅,2例因尿线变细疑有尿道瘢痕狭窄定期行尿道扩张后痊愈,无尿瘘、假道、尿失禁和明显性功能障碍。结论输尿管镜下尿道置管会师术操作简单、手术时间短、对患者创伤小、术后恢复快、效果确切、并发症少。可同时解除尿潴留并恢复尿道连续性,适合各种生命体征平稳的尿道断裂的早期治疗,值得临床推广。     

Method for securing a single-lumen urethral catheter in the female

When a single-lumen urethral catheter (catheter coudé) is applied for bladder catheterization in the female, secure fixation of such a catheter may present a problem. A simple method for fixation of a single-lumen urethral catheter in the female is described.     

Relative urethral leakage pressure versus maximum urethral closure pressure. The reliability of the measurement of urethral competence with the new tube-foil sleeve catheter in patients

In 78 female patients the urethral leakage pressure, defined as the intravesical pressure at which leakage starts from the urethral orifice, was estimated with the tube-foil sleeve catheter. In accordance with the definition of maximum urethral closure pressure, the relative urethral leakage pressure was defined as urethral leakage pressure minus intravesical resting pressure. In the same patients urethral closure pressure was also measured by urethral pressure profilometry with a flexible micro pressure-sensor catheter. On the average the ratio of relative urethral leakage pressure/urethral closure pressure was about 0.5. Relative urethral leakage pressure and urethral closure pressure were higher than the maximum detrusor pressure increases during detrusor instabilities in 21 continent patients with motor urge. The relative urethral leakage pressure correlated better with the detrusor pressure elevations at which fluid loss from the urethral orifice started in 24 motor urge incontinent patients than urethral closure pressure did.     

Endoscopic removal of knotted urethral catheter: a point of technique

Urethral catheter knotting is a rare complication of the simple and widely practiced clean intermittent self-catheterization. We report the endoscopic retrieval of a retained knotted feeding tube in a 12-year-old child. Various factors leading to such a rare complication and a new minimal invasive technique are described. To the best of our knowledge this technique has not been previously reported in the medical literature.     

Gene transfer to urethral strictures in rabbits: a preliminary report

OBJECTIVE: To assess the rationale for virus-mediated gene transfer into the urethra in vivo and in vitro, using a rabbit model, as this is an attractive approach to prevent recurrence after the endoscopic management of urethral strictures. MATERIALS AND METHODS: Primary cultures of rabbit urethral stromal cells were infected with adenoviral and retroviral solutions carrying a nucleus-targeted beta-galactosidase (beta-Gal) reporter gene (respectively 109 and 107 plaque-forming units/mL). In addition, to mimic the human clinical situation, a model was developed of thermally induced stricture in rabbit urethra which produced fibrotic stenosis within 15 days. Using a prototype channelled balloon catheter, these strictures were endoscopically dilated and then instilled with the beta-Gal adenoviral or retroviral constructs. RESULTS: The application of recombinant adenovirus and retrovirus harbouring a nucleus-targeted beta-Gal reporter gene to cultured rabbit urethral stromal cells resulted in a high transduction efficiency of up to 90% and 96%, respectively. Five days after infection, histochemical and immunohistochemical staining of the strictured urethrae showed a 3% rate of transfection targeted to stromal cells within the fibrosis, confirmed by polymerase chain reaction (PCR) analysis. Adjacent and distal spread of the virus was excluded by histochemistry, immunohistochemistry and PCR. CONCLUSION: These results represent the first report of endoscopic adenovirus and retrovirus-mediated gene transfer to the urethra. Although at a low rate, transduction reached stromal cells transmurally within the induced strictures and was site-specific.     

输尿管镜下尿道会师术治疗尿道断裂伤

目的探讨输尿管镜下留置导尿管治疗男性尿道断裂伤的方法与疗效。方法2007年5月～2012年4月采用输尿管镜下留置导尿管治疗男性尿道断裂伤18例。术中镜下寻找尿道球部或膜部近端断裂处,插入导丝于膀胱,沿导丝置入气囊导尿管恢复尿道连续性。结杲术后平均随访6个月,13例拔除导尿管后恢复正常排尿,5例合并尿道狭窄,其中3例结合尿道内切开、2例定期尿扩后排尿通畅。结论输尿管镜下留置导尿管治疗尿道断裂伤安全和有效。     

The effect of a fine urethral pressure-measuring catheter on urinary flow in females

Urodynamic evaluations of 221 female patients and 21 normal female subjects were performed to study the effects of a small ureteral catheter in the urethra on various voiding parameters. We found that the catheter induced a significant diminution of flow rate, interruption of flow, and stretching and flattening of the flow curves with respect to time. The most marked changes occurred in normal subjects and in patients with stress incontinence. The diminution of flow rate induced by the catheter was not strongly related to disease and varied so greatly within each statistical grouping that it was not possible to separate clearly the effects according to disease. Since the effects of the catheter were most marked on the normal population, catheter-induced reduction of flow rate could not be used as an index of urinary outflow obstruction.     

输尿管镜下尿道置管术治疗前尿道断裂疗效观察

目的:探讨输尿管镜下尿道置管术治疗前尿道断裂的方法与安全性.方法:回顾性分析应用输尿管镜下尿道置管术治疗前尿道断裂患者18例的临床资料.结果:拔管后正常排尿15例,一次性手术治愈占83.33%,最大尿流率(MFR)为(14.8±3.4)ml/s,平均手术时间为(22.7±3.3)min;术后尿道出血4例,占22.22%;0.5年后因尿道狭窄行开放手术3例,占16.67%.结论:在有效地控制治疗适应证的前提下,输尿管镜下尿道置管术治疗前尿道断裂是安全有效的方法.     

Transversus abdominis plane block: The analgesic efficacy of a new block catheter insertion method

BackgroundLocal anesthetic (LA) administration via a correctly placed block catheter could help optimum deposition in the transversus abdominis plane (TAP). The aim of the study is to assess the postoperative analgesic efficacy of TAP block achieved by initially injecting the LA through a catheter placed by ultrasound-guided Seldinger catheter insertion approach (USCIA).MethodsFifty patients scheduled for open inguinal hernia repair were randomized into two groups. Group USCIA: Patients received USCIA-TAP block. Group control: Patients did not receive TAP block. All patients received patient-controlled intravenous morphine postoperatively. The analgesic efficacy of USCIA-TAP block was assessed measuring the total amount of postoperative morphine requirements over the first 48 h postoperatively. Pain scores and level of patient satisfaction with pain relief after surgery were noted.ResultsThe mean cumulative morphine requirement over the first 48 postoperative hours was significantly lower in USCIA group in comparison with the Control group (18.1 ± 4.1 vs. 57.9 ± 5.3 mg). The success rate of USCIA-TAP block catheter placement was 88%. The pain score of USCIA group was significantly lower at 3, 6, 12, and 24 postoperative hours compared with the Control group. The USCIA group had a significantly higher rate of satisfaction with regard to pain control in comparison with the Control group at the 12th and 24th postoperative hours (9 {8–10} vs. 6 {5–7} and 9 {8–10} vs. 7 {6–8}, respectively).ConclusionThe use of a single dose of USCIA-TAP block reduced the total amount of morphine requirement over the first 48 postoperative hours for patients undergoing abdominal surgery.