Browsing by Author "Powell, Charles R."

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    Buccal mucosal graft urethroplasty in the treatment of urethral strictures: experience using the two-surgeon technique
    (Hindawi Publishing Corporation, 2010-01-08) Arlen, Angela M.; Powell, Charles R.; Hoffman, Henry T.; Kreder, Karl J.; Urology, School of Medicine
    At our institution, the majority of buccal mucosal graft urethroplasties are performed using a two-team approach with an otolaryngologic surgeon. We report our two-surgeon experience with buccal mucosal grafting for reconstruction of all anterior urethral strictures. Twenty-four men underwent autologous buccal mucosal graft urethroplasty between October 2001 and September 2008 for recurrent urethral stricture disease. Twenty-two underwent a single-stage repair and two underwent a two-stage repair. Medical charts were retrospectively reviewed for demographics, comorbidities, etiology, location and length of stricture, and prior interventions in order to identify predictors of buccal urethroplasty success, defined as no evidence of stricture recurrence. All patients underwent retrograde urethrogram and cystoscopy. Operative and anesthesia times were evaluated. We determined an overall success rate of 83.3% (20 of 24 cases). Mean anesthesia time for single-stage urethroplasty was 155 min and mean operative time was 123 min. One of the two two-stage urethroplasties experienced stricture recurrence (50%). The single-stage buccal graft success rate was 86.4% (19 of 22 cases). Two of the four who developed recurrent stricture disease that required intervention had undergone a previous mesh urethroplasty. Complications developed in four of 24 patients (16.6%), including superficial wound infection (one), superficial wound dehiscence (two), and abscess/fistula formation requiring reoperation (one). The buccal mucosa is an ideal tissue for both single- and two-stage substitution urethroplasty for patients with recurrent stricture disease. Our two-surgeon technique minimizes anesthesia and operative times, and contributes to the overall high success rate and relatively low complication rate.
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    A generic packaging technique using fluidic isolation for low-drift implantable pressure sensors
    (IEEE, 2015-06) Kim, Albert; Powell, Charles R.; Ziaie, Babak; Department of Urology, IU School of Medicine
    This paper reports on a generic packaging method for reducing drift in implantable pressure sensors. The described technique uses fluidic isolation by encasing the pressure sensor in a liquid-filled medical-grade polyurethane balloon; thus, isolating it from surrounding aqueous environment that is the major source of baseline drift. In-vitro tests using commercial micromachined piezoresistive pressure sensors show an average baseline drift of 0.006 cmH2O/day (0.13 mmHg/month) for over 100 days of saline soak test, as compared to 0.101 cmH2O/day (2.23 mmHg/month) for a non-fluidic-isolated one soaked for 18 days. To our knowledge, this is the lowest reported drift for an implantable pressure sensor.
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    Not all neurogenic bladders are the same: a proposal for a new neurogenic bladder classification system
    (TAU, 2016-01-25) Powell, Charles R.; Department of Urology, IU School of Medicine
    Neurogenic bladder (NGB) has long been defined as a clinical entity that describes a heterogeneous collection of syndromes. The common theme is a bladder disorder concomitant with a neurologic disorder. This definition does not give the clinician much information about the bladder disorder, nor how to treat it, or even what the natural history of the disorder is likely to be. It may be time for a new classification scheme to better define the bladder defect and prognosis, as well as inform treatment. We propose a classification system based on seven categories, each having a neurologic defect in a distinct anatomic location. This is termed SALE (Stratify by Anatomic Location and Etiology). In addition, the presence or absence of bowel dysfunction and autonomic dysreflexia will be reported. In the future, as more definite prognostic information can be gleaned from biomarkers, we anticipate adding urinary nerve growth factor (NGF) and urinary brain-derived neurotrophic factor (BDNF) levels to the definition. We expect the SALE system to efficiently describe a patient suffering from NGB and simultaneously inform the most appropriate treatment, follow-up regimen, and long-term prognosis.
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    Ossabaw Pig Demonstrates Detrusor Fibrosis and Detrusor Underactivity Associated with Oxidative Stress in Metabolic Syndrome
    (American Association for Laboratory Animal Science, 2020-10) Powell, Charles R.; Kim, Albert; Roth, Joshua; Byrd, James P.; Mohammad, Khalid; Khalid, Mouhamad; Alloosh, Mouhamad; Vittal, Ragini; Sturek, Michael; Urology, School of Medicine
    Metabolic Syndrome (MetS) has detrimental effects on the bladder, including detrusor underactivity. The progression and mechanism of disease are poorly understood. A swine model for diabetic bladder dysfunction (DBD) was established because of the pig's human-sized bladder and its ability to develop MetS by dietary modification alone. The hypothesis of this study is that this swine model will demonstrate oxidative stress associated with MetS, which contributes to both bladder fibrosis and detrusor underactivity (DU). Ossabaw pigs underwent dietary modification consisting of a hypercaloric, atherogenic diet for 10 mo to induce MetS, and were compared with a group of control (lean) pigs. Urodynamic studies were performed in both groups to confirm DU. Thiobarbituric acid reactive substances (TBARS) detected in the urine were used to measure oxidative stress activity in the urinary tract, and urinary IL17a was used to detect profibrotic activity. MetS was confirmed by assessing body weight, blood pressure, glucose tolerance, total cholesterol, and triglycerides. The MetS group exhibited an increase in the relative levels of urinary TBARS and IL17a. Bladder pressures at capacity were lower in the MetS group, suggesting DU. Histologic analysis of a cohort of control (lean) and MetS pigs revealed that as compared with the control pigs, the MetS pigs had significantly more collagen in the muscularis layer, but not in the submucosa or mucosa layer. In conclusion, the Ossabaw pig model for diet-induced MetS is associated with oxidative stress and profibrotic activity in the bladder, which results in DU. This has previously been shown in mice and rats, but never in pigs. This novel model will better represent human MetS and DBD because the mechanism and size of the pig bladder more closely resemble that of a human, resulting in a more valid model and facilitating further study into the signaling mechanisms responsible for this impairment.
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    Robotic Sacral Colpopexy Using Autologous Fascia Lata Compared with Mesh
    (Liebert, 2020) Bock, Megan E.; Nagle, Ramzy; Soyster, Mary; Song, Leo; Tachibana, Isamu; Hathaway, Jon K.; Powell, Charles R.; Urology, School of Medicine
    Objective: The objective is to compare robotic sacral colpopexy (RSC) utilizing autologous fascia lata with RSC with synthetic mesh in the treatment of pelvic organ prolapse (POP). Methods: We performed a prospective nonrandomized case comparison trial at a single institution. We compared RSC utilizing either synthetic mesh or autologous fascia lata in women with symptomatic POP, stages II through IV. The primary outcome was anatomic prolapse recurrence determined by the Pelvic Organ Prolapse Quantification (POP-Q) examination. Secondary outcomes included patient-reported outcomes such as the Urogenital Distress Inventory-6 (UDI-6) and Incontinence Impact Questionnaire-7 (IIQ-7). Complications were also recorded and categorized using the Clavien–Dindo (CD) system. The hypothesis is that autologous fascia lata would provide equivalent anatomic and patient-reported outcomes compared with mesh while eliminating mesh-related complications. Results: Sixty-four women underwent RSC with 19 (29.7%) receiving fascia lata graft. The overall operative time was greater in the fascia lata group with mean fascia lata harvest time of 24.8 ± 7.4 minutes. Intragroup comparisons of the fascia and mesh groups demonstrated significant improvement in pelvic measurements as well as patient-reported outcomes. Intergroup comparison demonstrated equivalent success rates at 12.1 ± 8.7 months follow-up. There was one apical failure in the fascia lata RSC group; however, the difference was not statistically significant (p = 0.30). Significant complications in the fascia lata harvest group included two CD-II and one CD-IIIb. In the mesh group there was one mesh erosion requiring surgical excision (CD-IIIb). Conclusion: This is the first comparison between RSC with autologous fascia lata and mesh. Short-term anatomic outcomes were similar with autologous fascia lata use without the risk of mesh erosion. Morbidity from graft harvest site was not trivial. These results emphasize the need for a randomized controlled trial.
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    Securing Mesh with Delayed Absorbable Suture Does Not Increase Risk of Prolapse Recurrence After Robotic Sacral Colpopexy
    (Liebert, 2020) Powell, Charles R.; Tachibana, Isamu; Eckrich, Bridget; Rothenberg, Jeffrey; Hathaway, Jon; Urology, School of Medicine
    Introduction and Objective: Nonabsorbable monofilament suture is traditionally used to secure vaginal mesh for robot-assisted sacral colpopexy (RASC) but can become exposed postoperatively requiring invasive vaginal removal. Polydioxanone delayed absorbable suture may avoid this. We sought to determine the objective and subjective impact of suture choice for mesh fixation. Materials and Methods: A cohort study was undertaken using a prospective registry and subjects were grouped based on type of suture at the time of RASC. Apical failure was defined as C point descent of >2 cm, anterior compartment failure was defined as pelvic organ prolapse quantification (POP-Q) Ba point of >0, and posterior compartment failure was defined as Bp point of >0. Patient-reported outcomes included urogenital distress inventory (UDI)-6 and QoL. Two-tailed t-test and chi-squared were used for analysis. Results: A total of 119 women underwent RASC between 2009 and 2016. Patients had similar preoperative characteristics (Table 1). All POP-Q, UDI-6, and quality of life (QoL) scores improved postoperatively (Tables 1 and 2). Apical failure was noted in 0, anterior failure was noted in 7 (average Ba +1.1 cm in failures), and posterior failure was noted in 4 (mean Bp +1.0 cm) at 16 months' follow-up. Failures in the anterior compartment were much more common in the nonabsorbable monofilament cohort (Table 2). Failures in the apical and posterior compartments were not significantly different between groups. Nine suture erosions were noted in the nonabsorbable monofilament cohort, five requiring excision in the clinic and two in the operating room. Two suture erosions were noted in the delayed absorbable cohort, 0 required excision. Postoperative UDI-6 and QoL scores did not vary significantly between groups (5.3 ± 4.0 vs 5.1 ± 4.0, p = not significant (NS), 2.8 ± 2.0 vs 2.8 ± 2.2, p = NS). Conclusion: Securing mesh with delayed absorbable monofilament did not appear to increase risk of failure in patients undergoing RASC and eliminates the need for suture excision postoperatively.
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    An Universal Packaging Technique for Low-Drift Implantable Pressure Sensors
    (Springer, 2016-04) Kim, Albert; Powell, Charles R.; Ziaie, Babak; Department of Urology, IU School of Medicine
    Monitoring bodily pressures provide valuable diagnostic and prognostic information. In particular, long-term measurement through implantable sensors is highly desirable in situations where percutaneous access can be complicated or dangerous (e.g., intracranial pressure in hydrocephalic patients). In spite of decades of progress in the fabrication of miniature solid-state pressure sensors, sensor drift has so far severely limited their application in implantable systems. In this paper, we report on a universal packaging technique for reducing the sensor drift. The described method isolates the pressure sensor from a major source of drift, i.e., contact with the aqueous surrounding environment, by encasing the sensor in a silicone-filled medical-grade polyurethane balloon. In-vitro soak tests for 100 days using commercial micromachined piezoresistive pressure sensors demonstrate a stable operation with the output remaining within 1.8 cmH2O (1.3 mmHg) of a reference pressure transducer. Under similar test conditions, a non-isolated sensor fluctuates between 10 and 20 cmH2O (7.4–14.7 mmHg) of the reference, without ever settling to a stable operation regime. Implantation in Ossabow pigs demonstrate the robustness of the package and its in-vivo efficacy in reducing the baseline drift.