Long-term outcome of secondary endopyelotomy after failed primary intervention for ureteropelvic junction obstruction.

OBJECTIVE: To evaluate the long-term outcome of secondary endopyelotomy after failed primary intervention for uretero-pelvic junction (UPJ) obstruction and to assess the effect of preoperative parameters on treatment outcome. METHODS: Twenty patients (13 men, seven women; mean age 30.7 years) who underwent secondary endopyelotomy after the failure of a primary intervention for the treatment of congenital UPJ obstruction were included in this retrospective analysis. Mean interval from primary treatment to secondary endopyelotomy was 27.2 months (range 3-123 months). The diagnosis of failure of the primary treatment was based on symptoms and the results of imaging studies. Treatment success was defined as symptomatic relief with either stable or improved renal function and improved wash-out shown on diuretic renogram or excretory urography. RESULTS: Mean follow-up was 47.2 months (range 6.2-138.8 months). Success rates were as follows: overall, 70%; after primary dismembered pyeloplasty, 66.7%; after primary endopyelotomy, 57.1%; after primary balloon dilatation, 100%. Kaplan-Meier estimates of success were 64.4% at 5 years. Six patients in whom the procedure failed at a mean of 13.8 months (range 4-33 months) were treated with open pyeloplasty (four patients), simple nephrectomy (one), and a repeat endopyelotomy (one). Grade 4 hydronephrosis and significant obstruction occurred more often in the failure group. CONCLUSIONS: Endopyelotomy is an acceptable minimally invasive secondary treatment option for UPJ obstruction. Preoperative severe hydronephrosis and the presence of a significant obstruction seem to be risk factors for the failure of a secondary endopyelotomy.

Paradoxical air embolism during percutaneous nephrolithotomy: a case report.

Air embolism is a rare complication of percutaneous nephrolithotomy. Patent foramen ovale, which is necessary in fetal circulation, is a potential route for emboli arising from the venous system to enter the systemic arterial circulation, resulting in paradoxical air embolism syndrome. A case of paradoxical air embolism during percutaneous nephrolithotomy is presented. To our knowledge, this is the first report of paradoxical air embolism associated with patent foramen ovale during percutaneous nephrolithotomy.

Effectiveness of noncontrast computed tomography in evaluation of residual stones after percutaneous nephrolithotomy.

PURPOSE: We prospectively compared the sensitivity of antegrade pyelography (AGP), plain film radiography (KUB film), and noncontrast thin-slice abdominal CT for detecting residual stones after percutaneous nephrolithotomy (PCNL). PATIENTS AND METHODS: We prospectively evaluated 50 patients (53 renal units) who underwent PCNL for radiopaque renal pelvic stones with noncontrast abdominal CT 1 month postoperatively. We compared the number and size of residual fragments, as determined by immediate postoperative AGP and 1-month KUB film and CT scan. RESULTS: Stone-free rates according to AGP, KUB film, and noncontrast CT were 73.6% (39/53), 62.3% (33/53), and 20.8% (11/53), respectively. However, if clinically insignificant residual fragments are included in the success rates, these rates increased to 84.9% (45/53), 83.0% (44/53), and 41.5% (22/53), respectively. Of the 22 patients in whom residual stones were detected by CT but not by KUB film, 10 (45.5%) had stones >4 mm in diameter on CT, with a mean size of 7.4 mm. The sensitivity for the detection of residual fragments was 47.6% for KUB films as judged by noncontrast CT. After CT, seven patients received extracorporeal shockwave lithotripsy for residual stones. CONCLUSIONS: Noncontrast thin-slice abdominal CT was the most accurate imaging method to determine the stone-free rate after PCNL. Noncontrast abdominal CT gives accurate information for selecting patients who may benefit from additional treatment and for planning follow-up.

Long-term outcome of endopyelotomy for the treatment of ureteropelvic junction obstruction: how long should patients be followed up?

PURPOSE: To evaluate the long-term success rate of endopyelotomy for the treatment of ureteropelvic junction (UPJ) obstruction. PATIENTS AND METHODS: Between January 1995 and December 2003, 85 endopyelotomies (10 percutaneous, 75 retrograde) were performed in 77 patients with a mean age of 35.2 +/- 13.9 years. The mean number of procedures per patient was 1.14, with 69 patients undergoing a single procedure. Endopyelotomies were performed using either a cold knife (N = 26), Ho:YAG laser (N = 47), or hook electrode (N = 12). Treatment success was defined as symptomatic relief with radiographic resolution or stabilization of renal function, as judged by an excretory urogram or diuretic renogram. Kaplan-Meier analysis was used to determine the long-term probability of success. RESULTS: With a median follow-up of 37.3 months (range 3-98 months), the overall success rate was 67.5%, and the median time to failure was 7.7 months (range 1-50 months). Kaplan-Meier estimates of success were 87.8% at 6 months, 76.9% at 12 months, 72.2% at 18 months, 68.7% at 24 months, 64.8% at 36 months, and 61.6% at 60 months. The success rate was not significantly affected by the etiology, surgical approach, or incisional method. Similarly, the degree of preoperative hydronephrosis or renal function did not affect the success rate. CONCLUSIONS: The success rate of endopyelotomy decreases as the follow-up increases. Although most failures were detected within 1 year of the procedure, it appears that follow-up of at least 36 months is required for patients who have undergone endopyelotomy for UPJ obstruction.

Highly sensitive signal detection of duplex dye-labelled DNA oligonucleotides in a PDMS microfluidic chip: confocal surface-enhanced Raman spectroscopic study.

Rapid and highly sensitive detection of duplex dye-labelled DNA sequences in a PDMS microfluidic channel was investigated using confocal surface enhanced Raman spectroscopy (SERS). This method does not need either an immobilization procedure or a PCR amplification procedure, which are essential for a DNA microarray chip. Furthermore, Raman peaks of each dye-labelled DNA can be easily resolved since they are much narrower than the corresponding broad fluorescence bands. To find the potential applicability of confocal SERS for sensitive bio-detection in a microfluidic channel, the mixture of two different dye-labelled (TAMRA and Cy3) sex determining Y genes, SRY and SPGY1, was adsorbed on silver colloids in the alligator teeth-shaped PDMS microfluidic channel and its SERS signals were measured under flowing conditions. Its major SERS peaks were observable down to the concentration of 10(-11) M. In the present study, we explore the feasibility of confocal SERS for the highly sensitive detection of duplex dye-labelled DNA oligonucleotides in a PDMS microfluidic chip.

Analysis of passive mixing behavior in a poly(dimethylsiloxane) microfluidic channel using confocal fluorescence and Raman microscopy.

Confocal fluorescence microscopy (CFM) and confocal Raman microscopy (CRM) have been applied to monitor the laminar flow mixing behavior in a poly(dimethylsiloxane) (PDMS) microfluidic channel. Two passive PDMS micromixing devices were fabricated for this purpose: a two-dimensional round-wave channel and a three-dimensional serpentine channel. The microscale laminar flow mixing of ethanol and isopropanol was evaluated using the CFM and CRM at various flow rates. The mixing behavior of confluent streams in the microchannel was assessed by determining the degree of color change in Rhodamine 6G dye on mixing using the CFM. However, it was also possible to quantitatively evaluate the mixing process without employing a fluorescence label using the CRM. The results show a strong potential for CRM as a highly sensitive detection tool to measure fundamental fluid mixing processes and to provide detailed information on chemical changes of non-fluorescent reaction mixtures in a PDMS microfluidic channel.

Enhancement of the protein loading density by a pre-cleaning process of a gold substrate: confocal laser scanning microscopic study.

The immobilization of glucose oxidase (GOx), using self assembled monolayers (SAMs) on gold surfaces, was investigated by grazing angle FT-IR spectroscopy, surface plasmon resonance (SPR) spectroscopy, and atomic force microscopy (AFM) in conjunction with confocal laser scanning microscopy (CLSM). To find an optimum condition for the maximum GOx loading density on gold surfaces, different cleaning protocols were examined. The loading density of GOx on surfaces was investigated by AFM and CLSM. In particular, CLSM was more effective for identifying the GOx density than AFM, since its scanning speed is much faster and it covers a larger area. Based on CLSM images of the GOx immobilized on the surfaces, it was concluded that the pre-cleaning process of gold substrates using different solvents, such as acetone, ethanol and 2-propanol, is very important for enhancing the GOx loading density. This result enables us to investigate an effective fabrication process in fabricating biosensors.

Endoscopic treatment of vesicoureteral reflux with polydimethylsiloxane in adult women.

OBJECTIVES: Subureteral injection of bulking agents to a refluxing ureteral orifice is an attractive alternative to open repair. We record our experience of the endoscopic subureteral injection of polydimethylsiloxane in women for vesicoureteral reflux (VUR). METHODS: From January 1997 to December 2001, 30 women (mean age 34.9 years) with 43 refluxing ureters underwent endoscopic treatment. The grade of VUR was I, II, III, and IV in 10, 16, 13, and 4 ureters, respectively. The indication for the procedure was VUR with a history of pyelonephritis in women of childbearing age or in whom antibiotic prophylaxis had been unsuccessful. All women underwent voiding cystourethrogram at 3 months and then yearly after the procedures. Follow-up ranged from 12 to 60 months (mean 26.5 months). RESULTS: Reflux was corrected in 34 ureters after a single injection; only 3 ureters needed a 2nd injection. The overall success rate was 86.0%: for grades I, II, III, and IV was 90.0%, 87.5%, 76.9%, and 100% respectively. The mean hospital stay was 1.31 days (range 1-8 days), and no remarkable surgical complications occurred. Most of the patients in whom VUR was cured or improved showed a reduction in laboratory-proven urinary infection rates. CONCLUSIONS: The endoscopic subureteral injection of polydimethylsiloxane in women with vesicoureteral reflux is an effective therapy with no associated morbidity.

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.

Virtual cystoscopy of the contrast material-filled bladder in patients with gross hematuria.

OBJECTIVE: The objective of this study was to evaluate the usefulness of virtual cystoscopy of the contrast material-filled bladder in evaluating patients with gross hematuria. SUBJECTS AND METHODS: Seventy-three consecutive patients who had gross hematuria and whose upper urinary tracts had a normal appearance on single-detector helical CT scans were prospectively evaluated with virtual cystoscopy. Source CT data for virtual cystoscopy were obtained on a multidetector CT scanner with 1.25-mm slice thickness and transferred to a workstation for interactive navigation using volume rendering. Two radiologists independently interpreted the virtual cystoscopic images, and discrepancies were resolved by consensus. All patients also underwent conventional cystoscopy. We assessed the agreement between the findings on virtual and conventional cystoscopy. Using conventional cystoscopy as the gold standard, we evaluated the usefulness of virtual cystoscopy as an aid in identifying bladder lesions and detecting abnormal bladders. RESULTS: Virtual cystoscopy depicted 60 lesions in the bladders of 43 patients. Fifty-six lesions (in 41 bladders) revealed on virtual cystoscopy were true-positive findings. Four lesions in two bladders with abnormal findings were false-positive. On virtual cystoscopy, the radiologists missed three lesions in two abnormal bladders that were identified on conventional cystoscopy. On virtual cystoscopy, 15 (88%) of 17 lesions smaller than 0.5 cm were identified. The agreement between the findings of virtual and conventional cystoscopy was excellent in the reviewers' identification of bladder lesions (kappa = 0.83) and detection of abnormal bladders (kappa = 0.89). The sensitivity and specificity of virtual cystoscopy were 95% and 87% for identifying bladder lesions and 95% and 93% for detecting abnormal bladders. CONCLUSION: Virtual cystoscopy of the contrast material-filled bladder is useful for the evaluation of the bladder in patients with gross hematuria.