Kari Hendlin

• BMEn and Chemistry
• Consultant at Independent

Objectives: To assess clinical safety (primary) and efficacy (secondary) of histotripsy for treatment of symptomatic benign prostatic enlargement (BPE) in a first-in human study. Methods: Twenty-five male subjects with moderate to severe lower urinary tract symptoms (LUTS), prostate size between 30 and 80 grams and no evidence of prostate cancer...

Extrinsic ureteral compression challenges a ureteral stent's ability to facilitate urinary drainage and to protect the kidney. Our purpose was to evaluate the performance of new metallic coil-based ureteral stents in terms of tensile strength and radial compression force. Three stent designs tested from Prosurg Inc included Passage 7.0F, Snake 6.0F...

To evaluate forces exerted on a stone with different ureteroscopic irrigation systems. A 3 mm steel simulated stone was welded to a 3F stone basket and inserted into the working channel of a 4.5F Wolf semirigid ureteroscope. The basket shaft was attached to a 50 g load cell. The urterescope was placed in a ureteral model (14F silicon tubing). Simul...

To conduct a comparison of physical and mechanical properties for 5 commonly used guidewires to assess advantages of wires for specific applications. Tests on guidewires (0.035" diameter; straight, flexible tip) included tip bending, shaft buckling, lubricity, and tip puncture measurements. Guidewires included 2 hybrid wires: the U-Nite (Bard Urolo...

To evaluate the radial dilation force and basket opening dynamics of three small (<1.5F) stone baskets. Boston Scientific OptiFlex (1.3F), Cook N-Circle Nitinol Tipless Stone Extractor (1.5F), and Sacred Heart Medical Halo (1.5F) baskets were tested for radial dilation force in 10 repetitions using a floating block atop a stationary block secured t...

Three small diameter (<1.5F) stone baskets have recently been introduced. Our objective was to evaluate the stone capture rate of these baskets in an in vitro ureteral model and an in vitro caliceal model using novice, resident, and expert operators. Sacred Heart Medical Halo™ (1.5F), Cook N-Circle(®) Nitinol Tipless Stone Extractor (1.5F), and Bos...

Stenting is the best approach to manage ureteral extrinsic compression and depends on intraluminal patency, which is mainly determined by cross-sectional stability. We evaluated the resistance to extrinsic compression of the Silhouette Scaffold Device and its ability to simultaneously maintain intraluminal flow. Four 8 F Silhouette stents of differ...

Ureteral stents are commonly used to facilitate kidney drainage but they may produce significant stent symptoms and morbidity, and require a secondary procedure for removal. Previous biodegradable stents showed bio-incompatibility or inconsistent degradation, requiring extra procedures to remove undegraded stent fragments. We previously reported a...

Ureteral stents commonly become infected or encrusted. Various coatings have been developed to decrease bacterial adherence. To our knowledge there has been no in vitro testing of coating with heparin to date. We determined the effects of heparin coating on bacterial adherence of common uropathogens and physical stent properties. Heparin coated Rad...

To evaluate the efficacy of celecoxib as an analgesic and medical expulsive agent in acute renal colic. A prospective randomized double-blind study was conducted on patients presenting with an obstructing ureteral calculus < 10 mm in largest diameter. Patients were randomized to 400 mg of celecoxib, followed by 200 mg every 12 hours for 10 days, or...

The Resonance metallic ureteral stent (Cook Medical, Bloomington, Indiana, USA) has been introduced for the management of extrinsic-etiology ureteral obstruction for time periods up to 12 mo. The current study aims to determine short- and medium-term effectiveness of the Resonance stent in malignant and benign ureteral obstruction. In total, 50 pat...

To evaluate the physical properties of urethral catheters that are predictive of ease of placement and risk of urethral trauma: Stiffness, buckling, and friction forces. Eleven Bard Lubri-Sil and 10 Kendall Dover 16F Foley catheters were tested using a linear motion stage driven by a stepper motor with a resolution of 5 microns/step or by hand. For...

The dynamics of percutaneous balloon expansion may differ with increasing extrinsic compressive forces and increasing inflation pressures. This study compares the ability of percutaneous balloons to expand under different radial constrictive forces. Three 30F nephrostomy balloons were tested: Bard X-Force, Boston Scientific Microvasive Amplatz Trac...

Instrumentation is the key to success in endourology. Indeed, endourology could be redefined as "enginurology," as the marriage between engineering and urology, and developing instrumentation to improve patient outcomes is the key facilitator in the advancement of minimally-invasive techniques. This review article will identify the evidence base th...

We evaluated the efficacy of alfuzosin as medical expulsive therapy for distal ureteral stone passage. A total of 76 patients with a distal ureteral calculus provided consent for the study. Patients were randomized between placebo and study medication, and investigators and patients were blinded to the randomization scheme. Followup was done on a w...

To evaluate forces exerted on a stone with different ureteroscopic irrigation systems that could impact stone migration during ureteroscopy. A 3-mm steel simulated stone was welded to a 3F stone basket. The basket wire was then backloaded into the working channel of a 4.5F Wolf semirigid ureteroscope. The basket shaft was attached to a 50 g load ce...

To evaluate the performance of coil-based ureteral stents in terms of tensile strength and the radial compression force. Three Cook Resonance (RES) metallic coil stents and three coil-reinforced Applied Medical Silhouette (SIL) ureteral stents were tested. An MTS MicroBionix Testing System using Testworks II software, vibration isolation table, and...

We describe and demonstrate a simple method to release a stone from a basket that emphasizes the importance of lateral deflection of the ureteroscope while opening and advancing the basket. This technique works well with semirigid and flexible ureteroscopes and all stone baskets, although some difficulty may be encountered with flat-wire baskets.

To evaluate physical characteristics of next-generation access sheaths that impact clinical failure. Testing of the Cook Flexor (12/14 Fr x 35 cm, Cook), ACMI UroPass (12/14 Fr x 38 cm, ACMI), Bard Aquaguide (11/13 Fr x 35 cm Bard), and Boston Scientific Navigator (11/13 Fr x 36 cm BSCI-11, 13/15 Fr x 36 cm BSCI-13) was performed on a linear motion...

Ureteroscopy has become a very effective treatment option for ureteral and upper tract abnormalities. The reported complication rates have ranged from 1.5% to 13% for perforations and have been less than 1% for avulsions. We present a study that quantified the ureteral avulsion force in porcine ureters and ureteral perforation forces in human and p...

To evaluate the effect of the early use of the vacuum erection device (VED) on erectile dysfunction (ED) and penile shortening after radical retropubic prostatectomy (RP), as these are important concerns for men choosing among treatment alternatives for localized prostate cancer. Twenty-eight men undergoing RP were randomized to early intervention...

The Weck clip has emerged as an attractive option for laparoscopic vascular control. It is secure and easy to use. However, once fired, the clip can be difficult to remove. We describe a novel technique for the safe removal of misdirected Weck clips using the Harmonic scalpel.

Conduct a prospective randomized single-blind comparison of two nephrostomy catheter designs, evaluating specifically intraoperative placement and postoperative comfort. The single-blind, prospective randomized trial was conducted with institutional review board approval. All patients undergoing percutaneous nephrolithotomy who gave informed consen...

To evaluate the coil strength before and after urine exposure and the stiffness of commercially available double-J ureteral stents because both properties may affect stent performance and patient comfort. Twelve commercially available 6F ureteral stents were tested for coil strength before and after 30 days of urine exposure. The proximal end of ea...

To evaluate the force required to radially compress ureteral stents and the impact of compression on stent performance across a broad range of stent sizes and manufacturers. Fourteen ureteral stents ranging in size from 6F to 10.3F were evaluated for radial compression using an MTS Micro Bionix Testing System using Testworks II software, 5N load ce...

To evaluate in an in vitro study the irrigation and drainage capabilities of a variety of available catheters. Three-way Foley catheters are used when irrigation of the bladder is anticipated to prevent or manage blood clots in the bladder. Six operators applied maximal one-handed pressure irrigation with a catheter-tip syringe through the irrigati...

To evaluate the impact of percutaneous nephrostomy catheter configuration on drainage flow and retention strength. The Cook nephrostomy 16F (symmetric balloon), Bardex Council 16F (eccentric balloon), Microvasive Flexima 14F (pigtail), and Bardex Malecot 16F (flange) nephrostomy catheters were attached to an artificial renal pelvis (12-in.-round la...

The dynamics of ureteral balloon expansion may differ with increasing extrinsic compressive forces and inflation pressures. This study compared the ability of ureteral balloons to expand under different conditions. The balloons tested were the Cook Accent, Ascend, Ascend AQ, and Pursuit; the Bard 195503 and UroForce; and the Boston Scientific Micro...

To evaluate one aspect of tipless and helical stone basket function that is critical for ureteral stone extraction: the radial-dilation force. Nine commercially available tipless baskets and five commercially available helical stone baskets were tested. Two Teflon blocks were positioned with the lower block sitting on a digital scale and the upper...

To compare irrigant flow characteristics through standard working channels (3.6F to 4.5F) and a dual-diameter working channel. Irrigant flow is critical for adequate visualization during endoscopic procedures. Working channels were created out of 80 cm of light wall polytetrafluoroethylene (PTFE) tubing (inner diameter 3.6F, 4.0F, and 4.5F) with a...

Tipless stone baskets facilitate caliceal calculi extraction during flexible ureteroscopy. We evaluated the stone capture rate of 9 commercially available tipless stone baskets in an in vitro model using novice and expert operators. The Microvasive Zerotip (2.4Fr, 3.0Fr), Cook N-Circle (2.2Fr, 3.0Fr, 3.2Fr), Bard Dimension (3.0Fr, Sacred Heart Medi...

To evaluate 17 commercial stone baskets for characteristics we believe are favorable for stone extraction. The ACMI (Sur-Catch 3.0), Bard (Dimension 3.0), Boston Scientific (Zero-tip 2.4/3.0, Segura 2.4/3.0, Gemini 3.0, Parachute 3.1), Cook (N-Circle 2.2/3.0/3.2, N-Force 3.2, Flatwire 2.0), and Sacred Heart (Halo 1.9, Vantage 2.4, Summit 3.0, Hercu...