The self-expanding metallic ureteric stent in the long-term management of benign ureteric strictures

OBJECTIVE: To evaluate and assess the long-term complications of using the thermo-expandable, nickel-titanium alloy stent (Memokath 051, Engineers & Doctors A/S, Hornbaek, Denmark) for managing benign ureteric strictures. PATIENTS AND METHODS: Over a 3-year period, 13 Memokath stents were inserted in 11 patients (mean age 58 years, range 35-85) with 12 lower ureteric strictures. The cause of the stricture was benign in all cases, i.e. radiation fibrosis in three, retroperitoneal fibrosis, ischaemic uretero-ileal anastomosis and scarring after ureteroscopy in two each, and diathermy damage, extraluminal endometriosis and stone passage in one each. Four stents were 9 F with proximal expansion to 17 F and the other nine used were 10.5 F with proximal expansion to 20 F. The patients were followed for a mean (range) of 18 (1.5-33) months. RESULTS: No complications or side-effects occurred with nine stents; four stents were removed at a mean (range) of 16.3 (4-33) months. Three of these had become encrusted, two of which had been placed in patients who had either a history of stone disease or recurrent urinary tract infection. The other stent had migrated. CONCLUSION: The Memokath stent appears to have a useful role in managing benign ureteric strictures, but it must be closely monitored in patients who are predisposed to encrustation.     

Application of paclitaxel-eluting metal mesh stents within the pig ureter: an experimental study

OBJECTIVE: The purpose of the present study is to compare the standard bare metal stents (BMS) with the Paclitaxel-Drug Eluting Stent (DES) in the ureter of a pig model. MATERIALS AND METHODS: We report on an experimental study with ten female pigs weighing between 25 and 30 kg. The stents were randomly placed in either the right or left ureter in each of 10 study animals, for a total of 20 stented ureters. Ten ureters were stented with an R-Stent (Orbus Medical Technologies, Hoevelaken Netherlands), and ten with a Paclitaxel-Eluting Coronary Stent (Boston Scientific, Natick, MA, USA). Patency was measured by radiograph of the nephrostomy tract, intravenous urography and virtual endoscopy at 24 hours and 21 days after the initial procedure, respectively. RESULTS: Free flow of urine through the stents into the bladder was documented in all stented ureters 24 hours after stent insertion by radiograph of the nephrostomy tract. At the 21 day follow-up examination, 5 R-Stents were found to be completely occluded and two partially stenosed, whereas no occluded stent was detected in the Paclitaxel-DES group. Pathology examination of the stents at 21 days follow-up showed that the obstructed R-Stents generated severe inflammation with metaplasia of the urothelium. The Paclitaxel-Eluting MS generated a mild inflammatory response within the ureteral lumen at the site of the stent, without hindering ureteral patency. R-stents proved to develop more hyperplasia compared to the Paclitaxel-Eluting MS. CONCLUSIONS: Paclitaxel-DES, when compared with the standard R- Stent BMS, generated less inflammation and/or hyperplasia of the surrounding tissues, thus maintaining ureteral patency. Long-term animal trials are required to further validate our results.     

肠道支架减压在左侧大肠癌梗阻一期切除吻合中的应用

目的 探讨术前肠道支架减压在左侧大肠癌梗阻一期切除吻合中运用的安全性和有效性.方法 回顾性分析2005年5月至2008年9月浙江中医药大学附属第一医院收治的97例左侧大肠癌患者临床资料.支架联合手术组46例,为左侧大肠癌合并肠梗阻的患者,成功放置肠道支架减压后行手术一期切除吻合治疗.单纯手术组51例,为无梗阻的左侧大肠癌而限期手术治疗的患者.观察两组患者术后胃肠功能恢复、术后住院时间、并发症发生情况.采用t检验、χ~2检验对数据进行分析.结果 支架联合手术组46例中,1例乙状结肠癌患者于肠道支架植入术后第4天出现肠道穿孔致弥漫性腹膜炎,急诊行乙状结肠癌根治术.45例均顺利完成一期手术治疗,术后11～16 d痊愈出院,1例患者术后10 d死于呼吸道感染及心功能衰竭.术后随访4～48个月.两组患者在术后肛门排气时间、住院时间、围手术期并发症发生率、复发转移率、随访期内生存率方面比较差异无统计学意义(t=0.164,1.358,χ~2=0.252,1.200,0.580,P>0.05).结论 术前肠道支架减压是治疗左侧大肠癌梗阻患者安全、有效的方法.     

Thrombogenicity of metallic vascular stents in arteries and veins--an experimental study in pigs

Endovascular expanding metallic stents were percutaneously implanted in the iliac arteries and veins of pigs. The vessels had been stenosed by a ligature of catgut 4 weeks prior to this. Platelets were labeled with Indium 111 and the deposition onto the dilated and stented areas was dynamically registered for 240 min with a scintillation camera. All six arterial and six venous stents remained patent throughout the examination period. At the site of arterial stenting there was an increase, of deposited activity, and in the veins a decrease. These experimental findings support the use of endovascular stents after dilation, especially in venous stenoses.     

Colostomy vs self-expanding metallic stents: comparison of the two techniques in acute tumoral left colonic obstruction

Self-expanding metallic stents is an alternative treatment to colostomy that is the treatment of choice in acute tumoral left colonic obstruction. AIM OF THE STUDY: To compare morbidity, mortality, length of hospital stay and treatment performed after desobstruction using the two methods. PATIENTS AND METHODS: Thirty-three patients admitted for acute obstruction of the left colon were retrospectively separated in two groups depending on the type of intervention performed to treat the obstruction ("colostomy" group: 17 patients and "self-expanding stent group": 16 patients). We studied complications after desobstruction, hospital courses and surgical strategy performed after the acute phase. RESULTS: Time between desobstruction and colectomy was shorter in the "self-expanding stent group" than in the "colostomy group" (18.5 days versus 73 days). Age superior than 75 years and colostomy were the two main factors predicting the risk of definitive colostomy (P < 0.05). Global mean hospital stay was longer in the colostomy group (32.7 days versus 19.3 days, P = 0.02). Two perforations and one local recurrence occurred in the "self-expanding stent group". CONCLUSIONS: Self-expanding metallic stent can decrease the permanent colostomy rate and the number of interventions. The recurrence rate seems to be theoretically increased with the stenting method. Then, colostomy must be done for patients in curative situation. The self-expanding metallic stent should be used as a palliative care.     

Randomized clinical trial comparing self-expanding metallic stents with plastic endoprostheses in the palliation of oesophageal cancer

BACKGROUND: There is little evidence of the clinical and cost effectiveness of self-expanding metallic stents in the palliation of oesophageal cancer. The aims of this randomized trial were to evaluate the immediate and medium-term clinical outcomes following palliative intubation, examine patient quality of life, and evaluate costs and benefits from the perspective of the health service. METHODS: Fifty patients with inoperable oesophageal cancer were randomly allocated a metallic stent (n = 25) or plastic endoprosthesis (n = 25). Patients were followed up monthly until death. RESULTS: There was no significant difference in procedure-related complications or mortality rate between the two groups. There was a trend towards significance in favour of metallic stents with respect to quality of life and survival (median survival 62 versus 107 days for plastic prosthesis and metallic stent respectively). The cost of the initial placement of metallic stents was significantly higher than that of plastic endoprostheses ( pound 983 versus pound 296). After 4 weeks, cost differences were no longer significant. CONCLUSION: Metallic stents may contribute to improved survival and quality of life in patients with oesophageal cancer. Although initially more expensive, this cost difference does not last beyond 4 weeks. A larger trial involving approximately 300 patients would be required to detect a quality of life benefit of the magnitude observed in this trial.     

Treatment with self-expanding metallic enteral stents in occlusion caused by neoplastic stenosis of the sigmoid and rectum

From January 1999 to today 5 patients have been treated with self-expanding enteral stents for low intestinal occlusion in our General and Emergency Surgery Department. The patients' ages ranged from 75 to 90 years. Their general clinical condition was precarious and the emergency surgical treatment necessary was at very high risk. After a brief period of clinical monitoring the patients were submitted to a colonoscopy which revealed a tight neoplastic stenosis in the lowest portion of the colon. Self-expanding enteral stents measuring 9 by 20 mm were implanted in 4/5 patients, while, in the fifth patient, in view of the extent of the cancer, an oesophageal enteral stent measuring 12 by 23-28 mm was used. Over the following 24 hours we observed canalization and consequent disocclusion of the colorectum. It was thus possible to readjust the altered metabolic parameters, improve the respiratory and circulatory compliance and begin the study and the staging of the malignancy. Only two patients in acceptable general condition were submitted to radical surgery, while the other three were referred to our oncological radiotherapy centre. On the basis of this preliminary study we believe that in given clinical conditions and in a situation of emergency the use of self-expanding enteral stents, when indicated, is the only therapeutic measure capable of avoiding surgery carrying a very high risk and of creating the basis for appropriate, in-depth study of the cancer. In addition, it enables a better balance to be restored in the patient's general condition.     

Adoption of self-expanding metallic stents in the palliative treatment of obstructive colorectal cancer-look out for perforations!

Self-expanding metallic stents (SEMSs) are increasingly used for the palliative treatment of inoperable colorectal cancer. The aim of the current study was to analyze the safety and efficacy of SEMS in the palliative treatment of obstructive colorectal cancer. Between 2003 and 2006, SEMS placement was attempted in 26 patients suffering from inoperable obstructive colorectal cancer. The recovery of the patients and the outcome of this treatment modality were analyzed prospectively. SEMS was successfully inserted in 19 (73%) of 26 patients. In 16 (84%) of these 19 cases, the placement of SEMS was the definitive treatment of colorectal obstruction and no additional surgical palliation was needed. There were 3 (16%) colonic perforations related to stent application. SEMS insertion seems to be an effective alternative in the palliative treatment of patients with malignant colorectal obstruction. However, perforation is a dangerous complication of the procedure.     

Gianturco self-expanding metallic stents in treatment of tracheobronchial stenosis after single lung and heart and lung transplantation

Three patients with recurrent bronchial stenosis following single lung transplant (SLTx), and one patient with tracheal stenosis following heart-lung transplantation (HLTx), not responding to repeated dilatations (3 patients) and prolonged use of silastic stents (patient with tracheal stenosis), have been treated by the endoscopic insertion of Gianturco self-expanding metallic stents under fluoroscopic control. The stent resulted in immediate improvement in respiratory function in all four patients. One patient (SLTx) had early bronchial re-stenosis due to growth of granulation tissue within the stent which was successfully treated by cryotherapy. In one patient (HLTx), a left lower lobe bronchial stenosis developed 14 months after tracheal stenting. The metallic stent appears to be a promising device in the management of recurrent or resistant bronchial stenosis following SLTx or tracheal stenosis after HLTx.     

Elastic wall properties and collagen content in the ureter: An experimental study in pigs

We used an impedance planimetric method to look at elastic wall properties of ureter in ten anaesthetized pigs. A balloon was stepwise inflated and deflated in the ureteropelvine junction in the mid-ureter and in the intramural part of the ureter at the ureterovesical junction with pressures up to 70 cmH₂O, while the pressure and balloon cross-sectional area (Bcsa) were measured simultaneously. The elastic wall parameters were calculated from these measurements. At sacrifice, tissue samples were collected for analysis of collagen content of the ureteral wall. A non-linear clockwise relation (hysteresis loops) between Bcsa and balloon pressure was demonstrated. At maximal inflation of the balloon, the Bcsa, wall tension, and compliance were 35.28 ± 3.52. 38.44 ± 3.23, and 61.36 ± 8.09 mm², 230.71 ± 12.82. 242.38 ± 10.49. and 302.17 ± 20.03 cmH₂O × m, and 0.167 ± 0.047, 0.124 ± 0.002, and 0.182 ± 0.040 mm² × cmH₂O ¹ in the intramural part of the ureter, middle part, and ureteropelvine junction, respectively. The collagen content was 0.3249 ± 0.0077, 0.3301 ± 0.0066. and 0.3457 ± 0.0060 mg × mg ¹ dry defatted weight in the intramural part, in the middle, and in the ureteropelvine junction, respectively. The collagen content of the ureteropelvine junction was significantly higher than that of the middle of ureter (P < 0.02) and than that of the intramural part (P < 0.05). No significant correlations were found between the elastic parameters at maximal inflation of the balloon and the collagen content (P > 0.10) In conclusion the elastic wall properties were significantly different in the three ureteral segments and the collagen content of the ureteropelvine junction differed from that of the two distal locations. However, no relationship between the wall properties and the collagen content was found. © 1994 Wiley-Liss, Inc.     

Ureteric response to abdominal radiotherapy and metallic double‐pigtail ureteric stents: a pig model

OBJECTIVE

To examine the safety and compatibility of full‐length metal ureteric stents with abdominal radiotherapy.

MATERIALS AND METHODS

Four ureteric stents (Resonance^TM, Cook Urological, Ireland) (RS) and four RSs specially modified to contain thermocouples were placed unilaterally in eight pigs. The contralateral ureters of the same pigs served as their controls, and contained two polymeric ureteric catheters and two similar specially modified to contain thermocouples, while the remaining four control ureters remained intact. All pigs were exposed to abdominal radiotherapy. The dose rate was ≈5.3 Gy/min and a total radiation dose of 10 Gy was administered. Throughout the treatment the temperature was monitored by the RSs and catheters containing the thermocouples. The pigs were killed at 1 day (four), 7 days (two) and 15 days (two) after treatment, and all ureters examined histologically.

RESULTS

There was no statistically significant increase in RS and catheter temperature throughout the treatment in any of the treated pigs (P > 0.05). All histological lesions reported were due to radiation treatment. There were no differences in histology between the ureters containing RSs and controls.

CONCLUSION

RS usage is unrelated to any increase in stent temperature during abdominal radiotherapy and does not cause any further deterioration in the histology of the ipsilateral ureter, additional to that caused by the initial treatment.     

Intraoperative varicocele anatomy: a macroscopic and microscopic study.

Varicoceles are found in approximately 15% of all men in the general population and up to 41% of all infertile men. However, the exact location and relationship of internal and external spermatic arteries, veins and lymphatics within the inguinal portion of the spermatic cord have not been previously well described in infertile men. The results of detailed intraoperative macroscopic and microscopic surgical dissections of the spermatic cord and gubernaculum of 83 infertile men with 115 palpable varicoceles are described. Enlarged veins exiting the testis and traversing the gubernaculum were present in 48% of the dissections. Enlarged external spermatic veins were detected in 74% of all spermatic cords. Typically, small internal spermatic veins drained into a large vein more proximally in the spermatic cord. An average of 3.6 lymphatics per spermatic cord was identified and preserved during the dissections. A solitary testicular artery was observed in 69% of the dissections. The testicular artery was adherent to the posterior surface of a large internal spermatic vein in 50% of the dissections and was surrounded by a dense complex of closely adherent veins in 30%. To decrease the incidence of postoperative varicocele recurrences we suggest a surgical approach that addresses all identifiable dilated and connecting veins. These findings suggest that surgical approaches that include intraoperative access to and ligation of low inguinal (external spermatic) and gubernacular veins may cause fewer recurrences, unligated small internal spermatic veins may be a cause of varicocele recurrence, and large internal spermatic veins should be individually identified, dissected and ligated since the testicular artery and lymphatics are often adherent to these veins. Optical magnification is important to facilitate identification of lymphatics, testicular arteries and small internal spermatic veins.