Walid A Farhat

Publications (64)183.65 Total impact

• Article: Spatio-Temporal Distribution of Smads and Role of Smads/TGF-β/BMP-4 in The Regulation of Mouse Bladder Organogenesis

  Syed S Islam, Reza Bayat Mokhtari, Sushil Kumar, Joe Maalouf, Sara Arab, Herman Yeger, Walid A Farhat
  [show abstract] [hide abstract]
  ABSTRACT: Although Shh, TGF-β and BMP-4 regulate radial patterning of the bladder mesenchyme and smooth muscle differentiation, it is not known what transcription factors, local environmental cues or signaling cascades mediate bladder smooth muscle differentiation. We investigated the expression patterns of signaling mediated by Smad2 and Smad3 in the mouse embryonic bladder from E12.5 to E16.5 by using qRT-PCR, in situ hybridization and antibodies specifically recognizing individual Smad proteins. The role of Smad2 and Smad3 during smooth muscle formation was examined by disrupting the Smad2/3 signaling pathway using TβR1 inhibitor SB-431542 in organ culture system. qRT-PCR results showed that R-Smads, Co-Smad and I-Smads were all expressed during bladder development. RNA ISH for BMP-4 and immunostaining of TGF-β1 showed that BMP-4 and TGF-β1 were expressed in the transitional epithelium, lamina propia and muscularis mucosa. Smad1, Smad5 and Smad8 were first expressed in the bladder epithelium and continued to be expressed in the transitional epithelium, muscularis mesenchyme and lamina propia as the bladder developed. Smad2, Smad3 and Smad4 were first detected in the bladder epithelium and subsequently were expressed in the muscularis mesenchyme and lamina propia. Smad6 and Smad7 showed overlapping expression with R-Smads, which are critical for bladder development. In bladder explants (E12.5 to E16.5) culture, Smad2 and Smad3 were found localized within the nuclei, suggesting critical transcriptional regulatory effects during bladder development. E12.5 to E16.5 bladders were cultured with and without TβR1 inhibitor SB-431542 and assessed by qRT-PCR and immunofluorescence. After three days in culture in SB-431542, α-SMA, Smad2 and Smad3 expressions were significantly decreased compared with controls, however, with no significant changes in the expression of smooth muscle myosin heavy chain (SM-Myh. Based on the Smad expression patterns, we suggest that individual or combinations of Smads may be necessary during mouse bladder organogenesis and may be critical mediators for bladder smooth muscle differentiation.
  PLoS ONE 03/2013; · 4.09 Impact Factor
• Article: Spatio-Temporal Distribution of Smads and Roles of Smads/TGF-beta1/BMP-4 in Mouse Bladder organogenesis

  Syed S Islam, Reza Bayat Mokhtari, Sushil Kumar, Joe Maalouf, Sara Arab, Herman Yeger, Walid A Farhat
  [show abstract] [hide abstract]
  ABSTRACT: Although Shh, TGF-β and BMP-4 regulate radial patterning of the bladder mesenchyme and smooth muscle differentiation, it is not known what transcription factors, local environmental cues or signaling cascades mediate bladder smooth muscle differentiation. We investigated the expression patterns of signaling mediated by Smad2 and Smad3 in the mouse embryonic bladder from E12.5 to E16.5 by using qRT-PCR, in situ hybridization and antibodies specifically recognizing individual Smad proteins. The role of Smad2 and Smad3 during smooth muscle formation was examined by disrupting the Smad2/3 signaling pathway using TβR1 inhibitor SB-431542 in organ culture system. qRT-PCR results showed that R-Smads, Co-Smad and I-Smads were all expressed during bladder development. RNA ISH for BMP-4 and immunostaining of TGF-β1 showed that BMP-4 and TGF-β1 were expressed in the transitional epithelium, lamina propia and muscularis mucosa. Smad1, Smad5 and Smad8 were first expressed in the bladder epithelium and continued to be expressed in the transitional epithelium, muscularis mesenchyme and lamina propia as the bladder developed. Smad2, Smad3 and Smad4 were first detected in the bladder epithelium and subsequently were expressed in the muscularis mesenchyme and lamina propia. Smad6 and Smad7 showed overlapping expression with R-Smads, which are critical for bladder development. In bladder explants (E12.5 to E16.5) culture, Smad2 and Smad3 were found localized within the nuclei, suggesting critical transcriptional regulatory effects during bladder development. E12.5 to E16.5 bladders were cultured with and without TβR1 inhibitor SB-431542 and assessed by qRT-PCR and immunofluorescence. After three days in culture in SB-431542, α-SMA, Smad2 and Smad3 expressions were significantly decreased compared with controls, however, with no significant changes in the expression of smooth muscle myosin heavy chain (SM-Myh. Based on the Smad expression patterns, we suggest that individual or combinations of Smads may be necessary during mouse bladder organogenesis and may be critical mediators for bladder smooth muscle differentiation.
  PLoS ONE 03/2013; · 4.09 Impact Factor
• Article: Glans amputation during routine neonatal circumcision: Mechanism of injury and strategy for prevention.

  Joao L Pippi Salle, Lisieux E Jesus, Armando J Lorenzo, Rodrigo L P Romão, Victor H Figueroa, Darius J Bägli, Edward Reda, Martin A Koyle, Walid A Farhat
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  ABSTRACT: OBJECTIVE: Glans injury during circumcision is an uncommon yet potentially devastating complication. Its mechanism remains poorly understood. Herein we critically evaluate a case series and, based on common characteristics, hypothesize the mechanism of injury as well as means to prevent it. METHODS: Retrospective review of circumcision-related glans amputation cases referred for evaluation and management, focusing on detection of common history and presentation patterns in order to evaluate possible underlying mechanisms. RESULTS: A neonatal elective circumcision was conducted using a Mogen clamp and an oblique injury to the ventro-lateral aspect of the glans was noted in 6 cases referred over a 5-year period, suggesting a similar trauma pattern. The urethra was consistently involved. The amputated segments were reattached as free composite grafts in 2/6 cases. Three patients underwent delayed glansplasty months after the trauma in an attempt to restore natural symmetry and cosmesis. In one case a buccal mucosa graft was employed to rebuild the ventral coronal sulcus. CONCLUSIONS: Trauma pattern suggests that the ventral glans is at high risk for injury by traction on incompletely released ventral preputial adhesions with subsequent glans entrapment. Practitioners performing neonatal circumcisions, particularly with a Mogen clamp, should exercise adequate release of ventral adhesions to prevent this complication.
  Journal of pediatric urology 11/2012; · 1.38 Impact Factor
• Article: Early Postoperative Ultrasound After Open Pyeloplasty in Children with Prenatal Hydronephrosis Helps Identify Low Risk of Recurrent Obstruction.

  Rodrigo L P Romao, Walid A Farhat, Joao L Pippi Salle, Luis H P Braga, Victor Figueroa, Darius J Bägli, Martin A Koyle, Armando J Lorenzo
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  ABSTRACT: PURPOSE: Prediction of successful pyeloplasty can be challenging, particularly in asymptomatic children treated for worsening prenatally diagnosed hydronephrosis. We evaluated early noninvasive objective predictors of success in this population. MATERIALS AND METHODS: We reviewed patients who underwent pyeloplasty for asymptomatic, prenatally detected, worsening hydronephrosis treated between 2000 and 2010 with followup greater than 1 year. For all patients renal pelvis anteroposterior diameter in a mid transverse view and Society for Fetal Urology hydronephrosis grade were evaluated preoperatively and 3 to 4 months postoperatively. Aside from subjective evaluation based on change in hydronephrosis grade, we estimated the percentage of improvement in anteroposterior diameter (preoperative diameter - postoperative diameter/preoperative diameter). Repeat intervention after pyeloplasty arbitrarily defined failure. Patients were categorized into 3 groups, ie no failure on followup ultrasound (group 1), no failure with postoperative nuclear scan to document success (group 2) and failed pyeloplasty (group 3). ROC curves were plotted to correlate 4 variables with failure, namely preoperative anteroposterior diameter, postoperative anteroposterior diameter, percent improvement in anteroposterior diameter and subjective change in grade. RESULTS: Of 229 patients 192 (84%) who met inclusion criteria had ultrasound at 3 to 4 months postoperatively available. Mean age at surgery was 19 months and mean ± SD followup was 49.9 ± 27.7 months. Percent improvement in anteroposterior diameter and postoperative anteroposterior diameter measure were the most reliable variables to predict failure (AUC 0.88 and 0.86, respectively, p <0.0001), whereas preoperative anteroposterior diameter and subjective changes in grade were not good predictors (AUC 0.52, p >0.05). A percent improvement in anteroposterior diameter of 38% or greater or postoperative anteroposterior diameter of 11.5 mm or less was associated with success, with sensitivity of 100% and specificity of 61% and 55%, respectively. CONCLUSIONS: Percent improvement in anteroposterior diameter and postoperative pelvic anteroposterior diameter measure can provide objective guidance as to which patients need closer monitoring during followup, and can help select children at low risk for repeat intervention after pyeloplasty.
  The Journal of urology 10/2012; · 4.02 Impact Factor
• Article: Nephron sparing surgery for unilateral wilms tumor in children with predisposing syndromes: single center experience over 10 years.

  Rodrigo L P Romão, João L Pippi Salle, Cheryl Shuman, Rosanna Weksberg, Victor Figueroa, Bryce Weber, Darius J Bägli, Walid A Farhat, Ronald Grant, J Ted Gerstle, Armando J Lorenzo
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  ABSTRACT: Unilateral Wilms tumors associated with predisposing syndromes are treated with preoperative chemotherapy followed by surgical resection. We describe our experience with nephron sparing surgery for Wilms tumor in this population at risk for metachronous lesions. We conducted a retrospective review of all children with a predisposing syndrome who underwent nephrectomy for malignancy during a 10-year period (2000 to 2010). Data collected included age, mode of detection, tumor size, treatment, pathology results, followup time and recurrence episodes. From 2000 to 2010, 13 of 75 (19%) patients treated for Wilms tumor were diagnosed with predisposing syndrome(s). Eight patients with unilateral tumors were treated and had a mean age at diagnosis of 27 months (range 7 months to 9 years). Beckwith-Wiedemann syndrome, isolated hemihyperplasia, WAGR (Wilms tumor, Aniridia, Genitourinary abnormalities, mental Retardation) syndrome and isolated 11p13 deletion were the underlying diagnoses in 3, 2, 2 and 1 patient, respectively. All but 2 patients were diagnosed by screening ultrasound and 5 underwent preoperative chemotherapy. Median tumor size at surgery was 2.5 cm (range 1 to 13). Nephron sparing surgery was performed in 6 of 8 patients. Pathological study showed favorable histology Wilms tumor and nephrogenic rests in 6 and 2 patients, respectively. After a mean followup of 36 months (range 6 to 72) no recurrences were documented and all children had normal creatinine levels. Nephron sparing surgery appears safe for patients with unilateral Wilms tumor associated with predisposing syndrome(s), allowing for the preservation of renal function and good oncologic outcomes for the available followup time. If more studies confirm our observation, current recommendations for the surgical treatment of Wilms tumor may need to reemphasize the value of attempting nephron sparing surgery in this patient population.
  The Journal of urology 08/2012; 188(4 Suppl):1493-9. · 4.02 Impact Factor
• Article: Analysis of decisional conflict among parents who consent to hypospadias repair: single institution prospective study of 100 couples.

  Armando J Lorenzo, Luis H P Braga, Bozana Zlateska, Bruno Leslie, Walid A Farhat, Darius J Bägli, Joao L Pippi Salle
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  ABSTRACT: Although obtaining informed consent for distal hypospadias repair is common practice, little is known about the uncertainty or conflict between consenting parents faced with this decision. We systematically evaluated decisional conflict between parents who elected to have their child undergo hypospadias surgery. A total of 100 couples who were counseled about treatment options agreed to participate. Using a validated questionnaire, the Decisional Conflict Scale, we prospectively collected data on decisional conflict demographics, preference for circumcision, education level and prior knowledge about hypospadias. All parents elected surgical repair. Evidence of decisional conflict was encountered in 28% of participants (score less than 25 in 72%, 25 to 37.5 in 23.5%, greater than 37.5 in 4.5%). No statistically significant differences among parents were noted for total score (mean ± SD 16.1 ± 12 in mothers and 18.3 ± 12.6 in fathers) or subscales, except the informed subscale (mean ± SD 16.7 ± 14.3 in mothers and 21.1 ± 16.6 in fathers). Parental self-report of prior knowledge about hypospadias and preference for neonatal circumcision correlated with lower Decisional Conflict Scale scores (p = 0.02 and p <0.01, respectively). No statistical association was found between score and parental education level (p = 0.7) or expertise of the counselor (staff vs pediatric urology fellow, p = 0.4). These data describe the level of decisional conflict in couples agreeing to proceed with hypospadias repair, with no evidence of significant discrepancy between them. The novel description of factors related to decreased decisional conflict might help focus efforts aimed at minimizing difficulties encountered during the decision making process.
  The Journal of urology 06/2012; 188(2):571-5. · 4.02 Impact Factor
• Source

  Available from: Yasir Loai

  Article: Monitoring tissue development in acellular matrix-based regeneration for bladder tissue engineering: multiexponential diffusion and T2* for improved specificity.

  Hai-Ling Margaret Cheng, Yasir Loai, Walid A Farhat
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  ABSTRACT: Cell-seeded acellular matrices (ACMs) are a promising approach for the tissue engineering of soft tissues and organs, such as the urinary bladder. ACM contains site-preferred structural and functional molecules, and degradation products derived from ACM play important roles in tissue remodeling. Regeneration proceeds along concurrent trajectories of cell growth and matrix degradation, characterized by evolving biophysical and biochemical properties. The assessment of tissue development through a noninvasive imaging technique, such as MRI, must therefore be capable of distinguishing these concurrent biophysical and biochemical changes. However, although MRI provides exquisite sensitivity to tissue microstructure, composition and function, specificity remains limited. In this study, multiexponential diffusion and the effective transverse relaxation time T(2)* were investigated for their ability to assess cell growth and tissue composition, respectively. Bladder ACMs prepared with and without hyaluronic acid, and ACMs seeded with smooth muscle cells, were assessed on MRI. The slow diffusion fraction from multiexponential diffusion analysis demonstrated the best correlation with cellularity, with minimal influence from underlying matrix degradation. T(2)* measurements were sensitive to macromolecular content, specifically the presence of hyaluronic acid, without confounding influence from tissue hydration. T(2)* also appeared to be sensitive to cell filling of the matrix pore space. Compared with these metrics, commonly used MRI parameters, such as T(1), T(2) and single diffusion coefficients, were more limited in specificity. The use of T(2) to measure tissue structure and composition is limited by its large dependence on water content, and single diffusion can only reflect the overall characteristics of the extra- and intracellular environment. These findings are important for further development of more specific MRI methods for the monitoring of regeneration in tissue-engineered systems.
  NMR in Biomedicine 03/2012; 25(3):418-26. · 3.21 Impact Factor
• Article: Prospective cost analysis of laparoscopic vs. open pyeloplasty in children: Single centre contemporary evaluation comparing two procedures over a 1-year period.

  Katherine Moore, Armando J Lorenzo, Suzanne Turner, Darius J Bägli, Joao L Pippi Salle, Walid A Farhat
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  ABSTRACT: INTRODUCTION: Laparoscopy in pediatric urological surgery continues to gradually gain acceptance. Since economic implications are of increasing importance in our cost-containment environment, few studies have compared the expense associated with open to laparoscopic approaches. We present a prospective comparative cost-analysis between the laparoscopic (LP) and open pediatric pyeloplasty (OP). METHODS: Over a period of a year (2007-2008), 54 consecutives pyeloplasties were performed. The "traditional" OP was performed in 33 patients and the remaining 21 children underwent LP. Costs were prospectively collected for each group and divided based on amounts incurred by all different departments involved: nursing, laboratory, diagnostic imaging, pharmacy and operative room. RESULTS: Overall, the average cost for a LP was CDN$6240 compared to CDN$5079 for an OP with a median hospital stay of 2 days (range OP: 1-18, LP: 1-7). The main difference was found in operative room expenses (OP: $2508 vs. LP: $3925). The higher cost could not be solely explained by the use of disposable items, which only subtracts $335 per procedure (23.6% of the cost difference between OP and LP). Length of time spent in the operating room was 1.2 hours longer for the LP and appears to be the main factor explaining the cost difference. CONCLUSION: Our findings show that at our institution, pediatric LP is more expensive than OP. This cost difference is mainly due to operating room time. For cost-containment purposes, efforts aimed at increasing efficiency in the operating room may help equalize both approaches.
  Canadian Urological Association journal = Journal de l'Association des urologues du Canada 01/2012; · 1.24 Impact Factor
• Source

  Available from: Yasir Loai

  Article: Impact of bladder-derived acellular matrix, growth factors, and extracellular matrix constituents on the survival and multipotency of marrow-derived mesenchymal stem cells.

  Roula Antoon, Herman Yeger, Yasir Loai, Syed Islam, Walid A Farhat
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  ABSTRACT: We investigate the effect of bladder-derived acellular matrix (ACM) on bone marrow mesenchymal stem cells (BM-MSC) growth, survival, and differentiation, and evaluate the effect of collagen I and IV on BM-MSC differentiation potential to SMC. BM-MSCs isolated from CD1(_) mice were characterized by surface markers and differentiation into different lineages. BM-MSC SMC potential was further evaluated in stem cell medium alone or supplemented with TGF-β1 and recombinant human platelet-derived growth factor (PDGF-BB) on plastic, collagen I and IV using western blot. Furthermore, BM-MSCs were seeded on porcine derived ACM-fortified with hyaluronic acid and cultured in Mesencult+-growth factors, bone, or fat induction media for 3 weeks. Seeded constructs were evaluated by H&E, Ki67 assay, Oil red O, and Alizarin red stain. SMC differentiation was semiquantified via immunohistochemistry. BM-MSCs differentiated into fat and bone when induced. In Mesencult, BM-MSCs differentiated into SMC, expressing α-SMA, calponin, and MHC. BM-MSCs cultured on collagen I and IV reduced expression of SMC and MHC compared to plastic. On ACM-HA, BM-MSCs maintained multipotent state by differentiating to bone and fat when induced. In Mesencult, BM-MSC-seeded ACM-HA expressed α-SMA, calponin, and MHC. TGF-β1 and PDGF-BB enhanced SMC differentiation on collagens and ACM-HA. SMC proteins expression by BM-MSC varies depending on culture substrate. SMC markers are expressed higher on plastic and lower on collagen I, IV, and ACM-HA, suggesting these substrates preferentially maintain undifferentiated state of BM-MSC, which could be advantageous for incorporation of cell-seeded grafts to permit host modulation of tissue regeneration.
  Journal of Biomedical Materials Research Part A 01/2012; 100(1):72-83. · 2.63 Impact Factor
• Article: Bladder regeneration: great potential but challenges remain.

  Walid A Farhat
  Regenerative Medicine 09/2011; 6(5):537-8. · 3.72 Impact Factor
• Article: Editorial comment.

  Walid A Farhat
  The Journal of urology 09/2011; 186(3):1052. · 4.02 Impact Factor
• Article: Urinary Bladder Tissue Engineering Using natural Scaffolds in a Porcine Model: Role of Toll-Like Receptors and Impact of Biomimetic Molecules.

  Sevan Evren, Roula Antoon, Syed Islam, Herman Yeger, Katherine Moore, Reginald Gorczynski, Walid A. Farhat
  Cells Tissues Organs;. 09/2011;
• Source

  Available from: Lisieux Jesus

  Article: Comparative histological and functional controlled analysis of tubularized incised plate urethroplasty with and without dorsal inlay graft: a preliminary experimental study in rabbits.

  Bruno Leslie, Lisieux E Jesus, Yaser El-Hout, Katherine Moore, Walid A Farhat, Darius J Bägli, Armando J Lorenzo, João L Pippi Salle
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  ABSTRACT: We analyzed the histological and functional characteristics of the tubularized incised plate vs dorsal inlay graft urethroplasty in an experimental rabbit model. A total of 24 New Zealand male rabbits were randomly allocated into 4 groups, including sham operation, urethroplasty, tubularized incised plate urethroplasty and dorsal inlay graft urethroplasty. In the urethroplasty group the anterior urethral wall was half excised and the dorsal aspect was tubularized. In the tubularized incised plate group the same steps were followed but tubularization followed a longitudinal midline incision in the dorsal wall. In the dorsal inlay graft group the defect created by the dorsal incision was covered with an inner preputial graft. The animals were sacrificed at 4 and 8 weeks, respectively. The penis was immediately harvested for standardized passive flowmetry and subsequently fixed for histological staining. The grafts took in all animals. The tubularized incised plate defect was bridged by urothelium while in the dorsal inlay graft group the preputial graft kept its original histological characteristics. There was a significant decrease in average flow in the urethroplasty group (1.6 ml per second) compared to that in the sham operated group (3.4 ml per second) and to the other groups (p <0.05). However, no significant difference in average flow was found for the tubularized incised plate and dorsal inlay graft groups (2.4 and 2.2 ml per second, respectively, p = 0.7). In this short-term rabbit model dorsal inlay graft urethroplasty was feasible with good graft take and integration. Simple tubularization of a reduced urethral plate led to significantly decreased flow. Incision of the reduced plate with or without grafting improved the average flow. Findings in this experimental model do not support the superiority of dorsal inlay graft urethroplasty over tubularized incised plate urethroplasty in terms of urethral flow dynamics.
  The Journal of urology 08/2011; 186(4 Suppl):1631-7. · 4.02 Impact Factor
• Source

  Available from: Lisieux Jesus

  Article: Clinical evolution of vesicoureteral reflux following endoscopic puncture in children with duplex system ureteroceles.

  Lisieux E Jesus, Walid A Farhat, Antonio C M Amarante, Rafaella B Dini, Bruno Leslie, Darius J Bägli, Armando J Lorenzo, Joao L Pippi Salle
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  ABSTRACT: We studied the clinical evolution of vesicoureteral reflux after endoscopic puncture of ureterocele in pediatric duplex systems. We retrospectively reviewed charts of children with duplex system ureteroceles treated between 1992 and 2007. We analyzed patient age, prenatal diagnosis, urinary tract infection at presentation, differential renal function and preoperative vesicoureteral reflux. The fate of associated vesicoureteral reflux after endoscopic puncture of ureterocele was specifically addressed. We analyzed 60 patients with a mean age of 12 months, of whom 32 (52%) were diagnosed prenatally and 40 (66%) presented with a urinary tract infection. The majority of ureteroceles were ectopic, and pre-puncture vesicoureteral reflux was seen in 40 patients (67%). Postoperative voiding cystourethrogram was performed in 50 cases. New onset of vesicoureteral reflux occurred postoperatively in 24 patients (40%), mainly ipsilateral to the lower pole or contralaterally. Spontaneous vesicoureteral reflux resolution or improvement occurred in 16 of 22 patients (72%) observed after primary endoscopic puncture of ureterocele. Surgical intervention after endoscopic puncture of ureterocele was performed in 25 patients (42%), of whom 9 underwent more than 1 reparative procedure. Vesicoureteral reflux after endoscopic puncture of ureterocele may occur in the ipsilateral upper or lower poles, or in the contralateral renal segments. Therefore, the reflux is not necessarily related to the puncture itself. Vesicoureteral reflux after endoscopic puncture of ureterocele can resolve spontaneously in a significant number of patients. Therefore, initial management by close surveillance is warranted. Considering the simplicity of the procedure, our findings support that endoscopic puncture of ureterocele is an attractive alternative for the initial management of pediatric duplex system ureteroceles.
  The Journal of urology 08/2011; 186(4):1455-8. · 4.02 Impact Factor
• Article: Physiological changes in transperitoneal versus retroperitoneal laparoscopy in children: a prospective analysis.

  Cengiz Karsli, Yaser El-Hout, Armando J Lorenzo, Jacob C Langer, Darius J Bägli, João L Pippi Salle, Bruno Bissonette, Walid A Farhat
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  ABSTRACT: The choice of minimally invasive surgical approaches in pediatric urology is largely influenced by surgeon preference and experience. Little is known about the differences in physiological variables that might objectively influence the choice of surgical approach. We compared the cerebral and systemic hemodynamic effects of transperitoneal vs retroperitoneal CO(2) insufflation in children. After receiving ethical review board approval and written parental consent 36 pediatric patients undergoing transperitoneal (18) or retroperitoneal (18) laparoscopic surgery were enrolled in this study. A standardized anesthetic technique of isoflurane 1 MAC and remifentanil 0.2 mcg/kg per minute was used. Measured parameters included end tidal CO(2), middle cerebral artery blood flow velocity, heart rate and noninvasive mean arterial blood pressure. Transcranial Doppler ultrasound was used to measure middle cerebral artery blood flow velocity. Data were collected before, during and after CO(2) insufflation to 12 mm Hg pneumoperitoneum at regular intervals, including every minute for 10 minutes and every 2 minutes thereafter. Within group analysis was done using repeated measures ANOVA. Nonlinear regression analysis was used to determine the best fit and the relationship of each variable with time with p <0.05 considered significant. Patient age and weight were comparable in the 2 groups. Transperitoneal CO(2) insufflation resulted in a rapid parallel increase in middle cerebral artery blood flow velocity, mean arterial pressure and end tidal CO(2) during the first 8 minutes of pneumoperitoneum (p <0.05). Despite a continued increase in end tidal CO(2) thereafter middle cerebral artery blood flow velocity and mean arterial pressure attained a plateau within the first 8 minutes (p <0.05). In contrast, middle cerebral artery blood flow velocity and end tidal CO(2) increased progressively throughout the retroperitoneal CO(2) insufflation period (p <0.01). Cerebral blood flow velocity and end tidal CO(2) seem to increase progressively and gradually during retroperitoneal laparoscopy, in contrast to the more rapid increase and plateau effect during transperitoneal laparoscopy. Presumably the smaller absorptive surface in the retroperitoneal space explains this physiological difference.
  The Journal of urology 08/2011; 186(4 Suppl):1649-52. · 4.02 Impact Factor
• Article: Long-term followup and time to event outcome analysis of continent catheterizable channels.

  Bruno Leslie, Armando J Lorenzo, Katherine Moore, Walid A Farhat, Darius J Bägli, Joao L Pippi Salle
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  ABSTRACT: Creation of a continent catheterizable channel has facilitated the treatment of patients undergoing lower urinary tract reconstruction. We present outcomes and complications of a single center series of continent catheterizable channels followed out to 15 years. We retrospectively reviewed medical records of all children who underwent continent catheterizable channel (Mitrofanoff and Monti) between 1992 and 2007. Collected data included age, underlying diagnosis, associated procedures, stoma site, conduit type (appendix or reconfigured bowel), time to complications and need for subsequent surgical revisions. We identified 71 girls and 98 boys who underwent surgery at a mean age of 7.5 years (range 6 months to 22 years) and were subsequently followed for a mean of 5.8 years (8 months to 15 years). Underlying diagnoses included neurogenic bladder (36% of patients), bladder exstrophy (25%), epispadias (6%) and posterior urethral valves (6%). Concurrent procedures were conducted in 71% of cases, including augmentation (35%) and bladder neck plasty (22%) or closure (8%). Surgical revision was performed in 39% of patients, including stomal revision (18%), redo operation (8%), bulking agent injection (8%) and prolapse correction (4%). Although an initial peak was followed by a relatively stable complication-free period, delayed problems were detected on long-term followup. No statistically significant differences in complication rates were noted when comparing use of appendix and reconfigured bowel or different stoma locations. Despite an initial decrease in complications soon after continent catheterizable channel creation, late problems appeared on long-term evaluation. In our experience no specific factor predicted the likelihood of complications. Nevertheless, despite the need for surgical revision, good functional outcomes were evidenced in this series.
  The Journal of urology 06/2011; 185(6):2298-302. · 4.02 Impact Factor
• Article: Critical outcome analysis of staged buccal mucosa graft urethroplasty for prior failed hypospadias repair in children.

  Bruno Leslie, Armando J Lorenzo, Victor Figueroa, Katherine Moore, Walid A Farhat, Darius J Bägli, Joao L Pippi Salle
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  ABSTRACT: Although staged buccal mucosa graft urethroplasty is a well accepted technique for salvage urethroplasty, there are few reports on this procedure for redo hypospadias repair in children. We reviewed patients who underwent staged buccal mucosa graft urethroplasty for redo hypospadias repair. Age, quality of graft before tubularization, meatal position, presence of balanitis xerotica obliterans and complications were recorded. A total of 30 patients underwent 32 repairs during a 5-year period. Mean age at first stage was 7 years (range 1 to 17) and mean interval between stages was 9.3 months (5 to 13). Mean followup after second stage was 25 months (range 10 to 46). Meatal position before first stage was proximal in 44% of patients, mid shaft in 39% and distal in 16%. Nine patients had biopsy proved balanitis xerotica obliterans. There were no donor site complications. Four patients underwent a redo grafting procedure. Complications after second stage occurred in 11 of 32 repairs (34%), consisting of urethral stenosis in 5, glanular dehiscence in 3 and urethrocutaneous fistula in 3. A third of the patients had some degree of graft fibrosis/induration after the first stage. These patients were prone to more complications at second stage (9 of 11, 82%), compared to patients without these unfavorable findings (4 of 21, 19%; p<0.001). Presence of balanitis xerotica obliterans and meatal position were not significant factors associated with adverse outcomes. Staged buccal mucosa graft urethroplasty is a suitable technique for salvage urethroplasty. Complications after second stage were seen in approximately a third of patients, mainly those with fibrotic/indurated grafts.
  The Journal of urology 03/2011; 185(3):1077-82. · 4.02 Impact Factor
• Article: Determining compliance in clean intermittent catheterization for children with sensate urethra.

  Walid A Farhat
  Canadian Urological Association journal = Journal de l'Association des urologues du Canada 12/2010; 4(6):406. · 1.24 Impact Factor
• Article: Hypertension in children with poorly functioning unilateral kidneys: predictors of resolution after nephrectomy.

  Yaser El-Hout, Christoph Licht, Joao L Pippi Salle, Bo-Yee Ngan, Darius J Bagli, Armando J Lorenzo, Walid A Farhat
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  ABSTRACT: To identify the outcome of nephrectomy and predictors of hypertension (HTN) resolution in children with poorly functioning unilateral kidneys (differential renal function, DRF of < 15%), as concurrent HTN is often an indication for nephrectomy. Over a 7.5-year period, a single centre retrospective analysis of 89 children with unilateral nonfunctioning/poorly functioning kidney who underwent nephrectomy was conducted. Preoperative HTN was present in 18 children (20.2%). The childrens' characteristics (age, sex, body mass index, pathology, side), cause of nonfunction, diagnostics including preoperative proteinuria (dipstick) and DRF (nuclear scan), pathological features of specimen and follow-up were recorded. The mean (median; range) age at nephrectomy was 6.8 (5; 0.333-14) years with a mean (median; range) follow-up of 2.4 (3; 0.083-5.5) years. The mean (median; range) DRF was 6.5 (1; 0-15)%. Twelve of 18 children (67%) resolved their HTN. Age at nephrectomy, sex, side of nonfunctioning kidney and surgical approach (78% laparoscopic nephrectomy) did not correlate with HTN resolution. Persistence of HTN seemed to correlate with residual function of more than a DRF threshold of 5% (P = 0.05), the presence of preoperative qualitative proteinuria by dipstick (P = 0.03) and inflammation on pathology. HTN resolved after nephrectomy for poorly functioning unilateral kidney in most of the children. Persistence of HTN is probably multifactorial. Ipsilateral residual function before nephrectomy, preoperative proteinuria and pathological features of nephrectomy specimen may serve as clinically useful markers for outcome prediction.
  BJU International 11/2010; 106(9):1376-80. · 2.84 Impact Factor
• Article: Current status of retrograde intrarenal surgery for management of nephrolithiasis in children.

  Yaser El-Hout, Aziza Elnaeema, Walid A Farhat
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  ABSTRACT: To review the current status of retrograde intrarenal surgery (RIRS) for renal stones in children focusing on its indications, outcomes and success in the management of nephrolithiasis. Between 1988 and 2009, a comprehensive PubMed/MEDLINE literature review on RIRS was conducted. The available literature is limited and heterogeneous, skewed by favorable results on ureteral stone outcomes. However, recent case series report outcomes comparable to time-honored modalities: percutaneous nephrolithotomy and shock wave lithotripsy. Concerns about urinary tract damage are not substantiated by the yet available intermediate-term follow-up. RIRS seems to be an effective modality in pediatric nephrolithiasis management. However, long-term outcomes and comparative prospective randomized studies are awaited.
  Indian Journal of Urology 10/2010; 26(4):568-72.