Comparison of the learning curve and outcomes of robotic assisted pediatric pyeloplasty.

PURPOSE: We compared the learning curve and outcomes in children undergoing robotic assisted laparoscopic pyeloplasty during the initiation of a robotic surgery program compared to the benchmark of open pyeloplasty. MATERIALS AND METHODS: The records of our first consecutive 33 children undergoing robotic assisted laparoscopic pyeloplasty from 2006 to 2009 were retrospectively reviewed and compared to those of age and gender matched children who underwent open repair done by senior faculty surgeons before the initiation of our robotic surgery program. We compared operative time, complications, postoperative pain, length of stay and surgical success for 2 surgeons who adopted the robotic approach at an academic teaching institution. RESULTS: We found no significant differences in length of stay, pain score or surgical success at a median followup of 16 months. The number of complications was similar and they tended to be early and technical in the robotic assisted laparoscopic pyeloplasty group. Overall average operative time was 90 minutes longer (38%) for robotic assisted laparoscopic pyeloplasty (p <0.004). When evaluated chronologically, there was evidence of a learning curve. After 15 to 20 robotic cases overall operative times for robotic assisted laparoscopic cases was consistently within 1 SD of our average open pyeloplasty time with no significant difference in overall operative time (p = 0.23). Of the decrease in overall operative time 70% was due to decreased pyeloplasty time rather than peripheral time. CONCLUSIONS: There was similar safety and efficacy with robotic assisted laparoscopic pyeloplasty, although complications tended to be technical and early in our initial experience. Operative time decreased with experience and after 15 to 20 cases it was similar to that of open pyeloplasty with similar outcomes and surgical success.

Dual sources of vitronectin in the human lower urinary tract: synthesis by urothelium vs. extravasation from the bloodstream.

Vitronectin (VN), secreted into the bloodstream by liver hepatocytes, is known to anchor epithelial cells to basement membranes through interactions with cell surface integrin receptors. We report here that VN is also synthesized by urothelial cells of urothelium in vivo and in vitro. In situ hybridization, dideoxy sequencing, immunohistochemistry, and ELISA of urothelial cell mRNA, cDNA, tissue, and protein extracts demonstrated that the VN gene is active in vivo and in vitro. The expression of VN by urothelium is hypothesized to constitute one of several pathways that anchor basal cells to an underlying substratum and explains why urothelial cells adhere to glass and propagate under serum-free conditions. Therefore, two sources of VN in the human urinary bladder are recognized: 1) localized synthesis by urothelial cells and 2) extravasation of liver VN through fenestrated capillaries. When human plasma was fractionated by denaturing heparin affinity chromatography, VN was isolated in a biologically active form that supported rapid spreading of urothelial cells in vitro under serum-free conditions. This activity was inhibited by the matricellular protein SPARC via direct binding of VN to SPARC through a Ca(+2)-dependent mechanism. A novel form of VN, isolated from the same heparin affinity chromatography column and designated as the VN(c) chromatomer, also supported cell spreading but failed to interact with SPARC. Therefore, the steady-state balance among urothelial cells, their extracellular milieu, and matricellular proteins constitutes a principal mechanism by which urothelia are anchored to an underlying substrata in the face of constant bladder cycling.

Initiation of a pediatric robotic surgery program: institutional challenges and realistic outcomes.

BACKGROUND: Few institutions have reported their experience initiating a pediatric robot-assisted laparoscopic (RAL) program, and results vary regarding the outcomes for robotic surgery in children. We present the initiation of our pediatric robotic surgery program, provide suggestions for overcoming institutional challenges, and perform a comparative analysis to illustrate realistic outcomes during the learning curve. METHODS: Outcomes from consecutive children who underwent RAL surgery since the 2006 acquisition of the da Vinci® surgical system were retrospectively reviewed. To evaluate the safety and outcomes during the introduction of this new technology, we performed an outcome analysis of ureteral reimplantations comparing RAL cases to matched open controls. RESULTS: The first 50 RAL cases were performed over 20 months by two general and two urologic surgeons. Fourteen different procedures were performed successfully. The average patient age was 8.6 ± 5.7 years with 10 patients weighing less than 10 kg (20%). Three urologic cases were converted to traditional laparoscopy and two general surgery cases were converted to open. There were five mechanical failures. Initial outcomes comparing RAL and open ureteral reimplantations revealed similar length of stay, complications, and success with lower estimated blood loss in the RAL group. Overall OR time was 53% longer in the RAL reimplant group (361 ± 80 vs. 236 ± 58 min, p < 0.0001). CONCLUSION: Robotic surgery appears to be safe in pediatric patients for many procedures. Proper instruction and training precedes technological proficiency. The institutional learning curve may be magnified when there are multiple participating surgeons. Operative times for initial RAL cases can be expected to be greater than their open correlates.

The C-terminal Ca2+-binding domain of SPARC confers anti-spreading activity to human urothelial cells.

The anti-spreading activity of secreted protein acidic and rich in cysteine (SPARC) has been assigned to the C-terminal third domain, a region rich in alpha-helices. This "extracellular calcium-binding" (EC) domain contains two EF-hands that each coordinates one Ca2+ ion, forming a helix-loop-helix structure that not only drives the conformation of the protein but is also necessary for biological activity. Recombinant (r) EC, expressed in E. coli, was fused at the C-terminus to a His hexamer and isolated under denaturing conditions by nickel-chelate affinity chromatography. rEC-His was renatured by procedures that simultaneously (i) removed denaturing conditions, (ii) catalyzed disulfide bond isomerization, and (iii) initiated Ca2+-dependent refolding. Intrinsic tryptophan fluorescence and circular dichroism spectroscopies demonstrated that rEC-His exhibited a Ca2+-dependent conformation that was consistent with the known crystal structure. Spreading assays confirmed that rEC-His was biologically active through its ability to inhibit the spreading of freshly plated human urothelial cells propagated from transitional epithelium. rEC-His and rSPARC-His exhibited highly similar anti-spreading activities when measured as a function of concentration or time. In contrast to the wild-type and EC recombinant proteins, rSPARC(E268F)-His, a point substitution mutant at the Z position of EF-hand 2, failed to exhibit both Ca2+-dependent changes in alpha-helical secondary structure and anti-spreading activity. The collective data provide evidence that the motif of SPARC responsible for anti-spreading activity was dependent on the coordination of Ca2+ by a Glu residue at the Z position of EF-hand 2 and provide insights into how adhesive forces are balanced within the extracellular matrix of urothelial cells. .

Spreading of embryologically distinct urothelial cells is inhibited by SPARC.

The AON epitope of secreted protein acidic and rich in cysteine (SPARC) is a conserved motif expressed by human SPARC in a variety of human cell types. Through the use of a monoclonal antibody that recognizes this epitope, transitional epithelium was found to restrict expression of SPARC to the suprabasal and intermediate layer. Such intracellular expression was defined by immunoreactive signals that localized to the apical plasma membranes of suprabasal and intermediate cells. Polarization of SPARC to apical plasma membranes of suprabasal cells was retained in vitro by a subpopulation of cells that exhibited characteristics of suprabasal cells--cell-cycle quiescence, large cell volumes, and multiple nuclei. In contrast, the basal layer of transitional epithelium in vivo and cycling cells in vitro did not exhibit this apical staining pattern, but instead sequestered the SPARC polypeptide within urothelial cytoplasm and/or nuclei, as revealed by immunohistochemical analysis. Elution of soluble proteins and DNA from urothelial cells revealed the presence of SPARC within the nuclear matrix--and that SPARC colocalized with the nuclear matrix Ki-67 antigen. rSPARC activity was demonstrated and quantified with a rounding assay whereby the spreading of freshly plated cells was inhibited by recombinant SPARC in a concentration- and time-dependent manner. Inhibition of spreading was observed in urothelial cells derived from endoderm (bladder) and mesoderm (ureter) germ layers. Statistically significant differences were seen between urothelial cells from these two layers. Mesodermal cells recovered more slowly from the inhibitory effects of rSPARC, such that at hour 6 endodermal cells underwent significantly more spreading, as shown by a rounding index (RI). These experiments provide new insights about the matricellular trafficking of SPARC and suggest that intra- and extra-cellular localization patterns influence the development, homeostasis, and differentiation of transitional epithelium.