Robot-assisted laparoscopic pyeloplasty: Multi-institutional experience in infants.

INTRODUCTION: Robot-assisted laparoscopic pyeloplasty (RALP) has been gaining acceptance among pediatric urologists. Over 300 have been described in the literature, but few studies have evaluated the role of RALP in infants alone. OBJECTIVE: We sought to examine the operative experience and outcomes of RALP in a cohort of infants treated at multiple institutions across the United States. Our primary aim was to describe the safety and efficacy of RALP within this cohort. We recognize the challenges of performing minimally invasive surgery in small patients. In our paper, we address some technical considerations for the infant population. STUDY DESIGN: This multi-centered observational study collected data on subjects one year of age or less who underwent RALP between April 2006 and July 2012 at five institutions. The primary outcome was resolution of hydronephrosis, and secondary outcomes included surgical time and complications. RESULTS: A total of 60 patients (62 procedures) underwent RALP by six surgeons during the study period. All surgeons had > 5 years of experience beyond fellowship training. Mean surgical age was 7.3 months (SD ± 1.7 mo), 56 patients (95%) were diagnosed prenatally, and 59 patients (95%) had follow up imaging. Of these patients, 91% showed resolution or improvement of hydronephrosis. Two patients had recurrent obstruction and required additional surgery. Mean surgical time was 3 hours 52 minutes (SD ± 43 minutes). Seven (11%) patients reported intra-operative or immediate post-operative complications. DISCUSSION: This series found a 91% success rate for reduction or resolution of hydronephrosis, and an 11% complication rate. This is equivalent to modern series comparing open pyeloplasty to pure laparoscopic and robotic-assisted laparoscopic pyeloplasty, which report success rates ranging from 70-96%, and complication rates ranging from 0-24% for open pyeloplasty. We lacked a standardized technique amongst institutions. This was not surprising since there are not established technical benchmarks for this surgery. However, we specified multiple technical considerations for this unique patient population. CONCLUSION: The advantages of using robot-assistance to perform pyeloplasty in infants remain to be defined. This study cannot make that assessment due to small sample size. Nonetheless, this cohort is the largest robotic pyeloplasty series in infants to date. Seeing an excellent success rate and a low complication rate in this infant cohort is encouraging.

Low yield of early postoperative imaging after anastomotic urethroplasty.

OBJECTIVES: To evaluate the necessity and clinical effect of posturethroplasty imaging. METHODS: We reviewed our database of all urethroplasties performed by a single surgeon at our referral center during a 2-year period. The patients underwent voiding cystourethrography at a mean of 24 days postoperatively. The data analyzed included patient history and demographics, operative details, imaging results, and clinical outcomes. RESULTS: From 2007 to 2009, 210 patients underwent urethral reconstruction at our center. The patients undergoing meatoplasty or staged repairs were excluded, leaving 156 patients with postoperative imaging studies for analysis. Of 110 anterior urethroplasties, 59 (54%) consisted of excision and primary anastomosis, 28 (25%) an augmented anastomotic procedure, and 23 (21%) a pure ventral onlay with a flap or graft. All 46 posterior urethroplasties were performed with scar excision and primary anastomosis. Of the 156 patients, only 4 (3%) had extravasation on postoperative voiding cystourethrography (2 after posterior urethroplasty, 1 after augmented anastomosis, and 1 after ventral onlay)--all were successfully managed with catheter replacement and removal at a mean of 8 days afterward. None of the 59 men undergoing excision and primary anastomosis demonstrated extravasation. CONCLUSIONS: Extravasation on posturethroplasty voiding cystourethrography is rare after approximately 3 weeks of catheter drainage. Imaging can be omitted after uncomplicated excision and primary anastomosis urethroplasty.

Urethral rest: role and rationale in preparation for anterior urethroplasty.

OBJECTIVES: To report the outcomes of men treated initially with a period of urethral rest to allow tissue recovery before anterior urethroplasty. Many men referred to referral centers for anterior urethral reconstruction often present soon after the endoscopic manipulation of severe strictures. METHODS: We reviewed our database of all anterior urethroplasties performed by a single surgeon from 2007 to 2009. Urethral rest was accomplished by removal of the indwelling catheter, cessation of self-catheterization, and/or suprapubic urinary diversion before urethral reconstruction. RESULTS: During the study period, 210 patients underwent urethral reconstruction at our center. Men who had undergone meatoplasty or posterior urethroplasty were excluded, leaving 128 anterior urethroplasty patients available for analysis. Of these men, 28 (21%) were preoperatively given an initial period of urethral rest (median duration 3 months) because of recent urologic manipulation occurring immediately before referral. Of the 28 patients, 15 (54%) received suprapubic catheters. Urethral rest promoted identification of severely fibrotic stricture segments, enabling focal or complete excision in 75% (excision and primary anastomosis in 12 [43%] and augmented anastomosis in 9 [32%]), a percentage similar to that for those undergoing reconstruction without preliminary manipulation mandating urethral rest (82%). Stricture recurrence developed in 4 (14%) of the 28 rest patients, a rate again similar to that for the remainder of the urethroplasty population (10%). CONCLUSIONS: The results of our study have shown that recently manipulated anterior urethral strictures often declare themselves to be obliterative within several months of urethral rest, thus enabling successful urethroplasty by focal or complete excision.

Grafts are unnecessary for proximal bulbar reconstruction.

PURPOSE: We compared our experience with the reconstruction of proximal vs distal bulbar stricture to assess the role of excision and primary anastomosis vs graft procedures at each site. MATERIALS AND METHODS: We reviewed all urethroplasties done by a single surgeon during a 2-year period. Data analyzed included patient history and demographics, operative details, stricture length and site, and clinical outcome. The proximal bulbar urethra was defined as the segment within 5 cm of the membranous urethra and the distal bulb was defined as the adjoining segment extending to the penoscrotal junction. Cases involving the pendulous or posterior urethra were excluded from study. RESULTS: Of 210 urethroplasties from 2007 to 2009, 112 were done for bulbar strictures, including 72 (64%) for proximal bulbar strictures. All 72 cases were treated with excision and primary anastomosis. Median stricture length was 2 cm (range 1 to 5), although 31 of 72 strictures (43%) were of intermediate length (2.5 to 5 cm). Recurrence developed in 1 case (1.4%). Distal bulbar strictures in 40 of the 112 cases (36%) were treated predominantly with substitution urethroplasty in 36 (90%), and with excision and primary anastomosis in 4 (10%). Median stricture length was 3.75 cm (range 1.5 to 20). We noted intermediate length stricture in 18 of 40 cases (45%) and recurrence in 11 (28%). Of intermediate length strictures recurrence was much rarer after excision and primary anastomosis than after graft procedures (1 of 33 or 3.0% vs 6 of 16 or 38%, p<0.05). CONCLUSIONS: Location is critical when selecting an appropriate technique for bulbar urethral reconstruction. Excision and primary anastomosis are superior to grafts in the proximal bulb. Grafts are often unnecessary for reconstructing proximal bulbar strictures 5 cm or less.

An arsenite-inducible 19S regulatory particle-associated protein adapts proteasomes to proteotoxicity.

Protein misfolding caused by exposure to arsenite is associated with transcriptional activation of the AIRAP gene. We report here that AIRAP is an arsenite-inducible subunit of the proteasome's 19S cap that binds near PSMD2 at the 19S base. Compared to the wild-type, knockout mouse cells or C. elegans lacking AIRAP accumulate more polyubiquitylated proteins and exhibit higher levels of stress when exposed to arsenite, and proteasomes isolated from arsenite-treated AIRAP knockout cells are relatively impaired in substrate degradation in vitro. AIRAP's association with the 19S cap reverses the stabilizing affect of ATP on the 26S proteasome during particle purification, and AIRAP-containing proteasomes, though constituted of 19S and 20S subunits, acquire features of hybrid proteasomes with both 19S and 11S regulatory caps. These features include enhanced cleavage of peptide substrates and suggest that AIRAP adapts the cell's core protein degradation machinery to counteract proteotoxicity induced by an environmental toxin.