A comparative study of pediatric open pyeloplasty, laparoscopy-assisted extracorporeal pyeloplasty, and robot-assisted laparoscopic pyeloplasty.

PURPOSE: To compare the outcomes of open pyeloplasty (OP), laparoscopy-assisted extracorporeal (LEXP), and robotic-assisted laparoscopic pyeloplasty (RALP) for ureteropelvic junction obstruction in pediatric patients. METHODS: We retrospectively reviewed the age-matched cohort of 30 children who underwent OP, 30 who underwent LEXP, and 10 who underwent RALP at a single institution, from 1996 to 2014. Pre- and post-operative variables including success rate were compared among surgical groups. RESULTS: The mean age of the patients was 120.2 months, the Society for Fetal Urology grade was 3.6, the anteroposterior diameter was 3.1 cm, and the renal relative function was 44.0%. The distribution of laterality, mean body mass index, and preoperative anteroposterior pelvic diameter on ultrasound did not differ among groups. The mean length of hospital stay was significantly shorter in the RALP group (3.2 days) than in the OP (6.6 days) and LEXP (5.8 days) groups (p<0.001). The duration of analgesics use was shorter in the RALP group (1.1 days) than in the other groups (p<0.001). During the mean follow-up period of 49.0, 20.1, and 16.6 months, the success rate was 96.7%, 89.7%, and 100% in the OP, LEXP, and RALP groups, respectively, although this difference was not statistically different (p = 0.499). In multivariate regression analysis, the presence of crossing vessels was the only factor that decreased the success rate (hazard ratio: 46.09, 95% confidence interval: 2.41-879.6, p = 0.011). CONCLUSIONS: Patients who undergo RALP have a reduced hospital stay and lower use of pain medication; however, there is no difference in the success rates for OP, LP, and RALP surgeries. The presence of crossing vessels is a negative prognostic indicator for surgical outcome regardless of the surgical method.

Retrospective comparison of internally and externally covered retrievable stent placement for patients with benign urethral strictures caused by traumatic injury.

OBJECTIVE: The purpose of this article is to compare the clinical effectiveness and complications of externally and internally covered stents for the treatment of benign urethral strictures. MATERIALS AND METHODS: From July 2002 to June 2010, 59 retrievable self-expandable polytetrafluoroethylene-covered nitinol stents were placed in 33 men with benign urethral strictures. These included 34 internally covered stents placed in 18 patients (group I) and 25 externally covered stents in 15 patients (group E). Stents were routinely removed 4 months after placement from patients who experienced no complications. Complications, duration of stent placement, removal techniques, and maintained patency rates were compared in the two groups. RESULTS: Twenty-eight complications (82.4%) occurred in 15 patients in group I, whereas 12 complications (48%) occurred in six patients in group E (p=0.005). Three (16.7%) patients in group I and nine (60%) in group E had their stents electively removed without complications (p=0.010). Stent migration was more frequent in group I (47.1%) than in group E (24.0%). No tissue ingrowth was detected in group E, whereas six cases of tissue ingrowth occurred in group I (p=0.034). The standard technique was used more frequently in group E (70.8%). The median stent indwelling period was significantly shorter in group I than in group E (51.5 vs 114 days; p=0.34). CONCLUSION: Despite their relatively high complication rates, externally covered stents are more effective with fewer complications than internally covered stents in the treatment of benign urethral strictures.

Management of recurrent urethral strictures with covered retrievable expandable nitinol stents: long-term results.

OBJECTIVE: The purpose of this study was to evaluate the long-term clinical efficacy of temporary placement of covered retrievable stents in the management of recurrent urethral strictures. MATERIALS AND METHODS: During the period December 1998-December 2005, 32 men and one adolescent boy (mean age, 48.6 years; range, 16-73 years) with recurrent urethral strictures underwent fluoroscopically guided insertion of a total of 68 stents. Patients without complications underwent elective stent removal 2 or 4 months after stent insertion. Rates of clinical success (long-term clinical and radiographic resolution of urethral strictures) were assessed. The Mann-Whitney U test was used to compare the duration of stent placement in patients with long-term clinical resolution with that in patients with stricture relapse. RESULTS: Clinical success was achieved in 18 (55%) of the 33 patients. The mean duration of stent placement in patients with clinical success was significantly different from that in patients who had recurrences (p < 0.0001). Stricture relapse did not occur in only four (20%) of 20 cases of stent placement for 2 months. All 14 stent placements lasting at least 4 months resulted in long-term resolution after a mean follow-up period of 3.6 years. The most common complications necessitating early stent removal were stent migration (33.8% of stents) and tissue hyperplasia (20.6% of stents). CONCLUSION: Placement of a covered retrievable stent for a minimum of 4 months is effective in inducing long-term resolution of refractory urethral strictures. Stent migration remains the largest obstacle in achieving adequate duration of stent placement.

Renal angiomyolipoma with minimal fat: differentiation from other neoplasms at double-echo chemical shift FLASH MR imaging.

PURPOSE: To prospectively evaluate the diagnostic performance of double-echo gradient-echo (GRE) chemical shift magnetic resonance (MR) imaging in the differentiation of angiomyolipoma (AML) with minimal fat from other renal neoplasms, with pathologic examination or follow-up data serving as the reference standard. MATERIALS AND METHODS: Institutional review board approval and informed consent were obtained. Double-echo GRE chemical shift MR imaging was performed in 55 patients (29 men and 26 women; mean age, 49 years +/- 14 [standard deviation]) with 55 renal tumors, including 37 (67%) pathologically proved tumors (23 renal cell carcinomas, nine AMLs, two oncocytomas, two lymphomas, and one reninoma) and 18 (33%) clinically diagnosed tumors (17 AMLs and one indeterminate malignancy). All tumors showed no intratumoral fat and had homogeneous enhancement and a prolonged or gradual enhancement pattern on biphasic helical computed tomographic scans. Signal intensity was measured in the renal tumor and spleen on in-phase and opposed-phase images. The signal intensity index and tumor-to-spleen ratio in AMLs and non-AMLs were calculated and compared with the Student t test. Receiver operating characteristic (ROC) analysis was performed to evaluate the diagnostic accuracy of the signal intensity index and tumor-to-spleen ratio and to extract the optimal cut-off values in the differentiation of AMLs and non-AMLs. RESULTS: The signal intensity index and tumor-to-spleen ratio were different between AMLs (42% +/- 11 and -43% +/- 17, respectively) and non-AMLs (5% +/- 14 and -4% +/- 16, respectively) (P < .001). The area under the ROC curve was 0.975 for the signal intensity index and 0.952 for the tumor-to-spleen ratio. For differentiation of AMLs from non-AMLs, sensitivity and specificity were (a) 96% and 93%, respectively, with a signal intensity index of 25% and (b) 88% and 97%, respectively, with a tumor-to-spleen ratio of -32%. CONCLUSION: Double-echo GRE chemical shift MR imaging can be used to differentiate AML with minimal fat from other renal neoplasms.

Removal of retrievable self-expandable urethral stents: experience in 58 stents.

The purpose of this study was to retrospectively evaluate the safety and efficacy of removing retrievable self-expandable urethral stents using a retrieval hook wire. Under fluoroscopic guidance, the removal of 58 polyurethane or PTFE (polytetrafluoroethylene)-covered stents was attempted in 33 patients using a retrieval hook wire. Indications for removal were elective removal (n = 21), stent migration (n = 19), formation of tissue hyperplasia around or inside of the stent (n = 14), stent deformity (n = 3), and severe pain (n = 1). The mean time the stents remained in place was 64.8 +/- 42.9 days (range, 1-177 days). Fifty-six (97%) of the 58 stents were successfully removed using the retrieval hook wire despite the following difficulties; hook wire disconnection (n = 2), untied drawstrings (n = 3), and polyurethane membrane disruption/separation (n = 4). The removal procedure using a retrieval hook wire failed in two stents (3%) which had migrated into the urinary bladder. One of the two stents with migration into the urinary bladder was removed using a snare through the cystostomy route. The overall complication rate was 14% (seven hematuria cases and one urethral tear case), and all were minor and spontaneously resolved without further treatment. In conclusion, removal of retrievable urethral stents using a retrieval hook wire was safe and effective despite some technical difficulties. It is a useful method for allowing temporary stent placement and solving various complications of stent use.

Clinical features determining the fate of a long-term, indwelling, forgotten double J stents.

We review our experiences with forgotten stents and investigate the potential factors determining the degree of encrustation. Our series consists of nine cases of forgotten stent that had remained indwelling for more than 1 year (mean 36.1 months). We describe and compare their various clinical parameters in terms of encrustation. In addition, we briefly summarize our management schemes. All patients showed few stent related irritative symptoms. Six cases showing minimal or no encrustation shared the common feature of urine hypotonicity. Cystoscopic pullout was possible in these cases. The remaining three cases showed moderate to severe encrustation around the stent which required multiple procedures. Pyuria was observed in all cases and two patients had a history of urolithiasis. Finally, all cases were rendered stent and stone free. The fate of forgotten stents was dependent on the amount of encrustation around the stent. In our study, lithogenic history and presence of pyuria were associated with moderate to severe encrustation. Interestingly, patients showing urine hypotonicity tended to have a minimal encrustation on their stents and the stents were easily removed. Therefore, in patients with an impaired renal concentrating ability and a poor medical condition, the duration of indwelling stents might be safely prolonged if the patient has no risk factor for encrustation. As patients with forgotten stents are less likely to complain of stent related symptoms, thorough education of patients is important to prevent stent related complications.

Recurrent traumatic urethral strictures near the external sphincter: treatment with a covered, retrievable, expandable nitinol stent--initial results.

PURPOSE: To investigate the clinical effectiveness of a covered, retrievable, expandable nitinol stent in treating traumatic urethral strictures near the external sphincter. MATERIALS AND METHODS: The stent was 10 mm in diameter when fully expanded and 40-50 mm long. To make it removable, two nylon drawstrings were attached to its lower inner margin. Twelve consecutive men (19-67 years; mean age, 47 years) with traumatic urethral strictures near the external sphincter that were refractory to endoscopic urethrotomy were treated. With fluoroscopic guidance, a stent was placed to completely bridge the external sphincter. The stent was electively removed with a retrieval hook wire 2 months after placement. Stent placement and removal were successful in all patients, with no procedural complications. RESULTS: Mean maximum urine flow rate was 5 mL/sec (range, 3-7 mL/sec) before stent placement and 27 mL/sec (range, 16-40 mL/sec) at 1 week after placement. During the mean follow-up of 20 months (range, 2-37 months) after the first stent removal, strictures recurred in eight of 12 patients. For the eight patients with recurrence, a second stent was placed and 4 months later was removed from seven of the eight patients. During the mean follow-up of 18 months (range, 4-32 months) after the second stent removal, strictures recurred in two patients, in whom a third stent was placed and then removed 4 months later, with good results. Four (33%) of 12 patients, five (62%) of eight patients, and two (100%) of two patients were successfully treated with placement of the first stent, the second stent, and the third stent, respectively. In the remaining patient, the second stent remains in place. CONCLUSION: Placement of a covered, retrievable, expandable nitinol stent seems to be effective in treating urethral strictures near the external sphincter and warrants further investigation.