Radial dilation of nephrostomy balloons: a comparative analysis

PURPOSE: 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. MATERIALS AND METHODS: Three 30F nephrostomy balloons were tested: Bard X-Force™, Boston Scientific Microvasive Amplatz Tractmaster™, and Cook Ultraxx™. With a super stiff guidewire in place, the balloon tip was secured by elevated vice grips on either side of the balloon. A string was wrapped around the balloon center once, and incremental increases in load were added (2g, 42g, 82g, and 122g) to represent increasing extrinsic compression. The balloon was inflated with a contrast agent and circumference changes were measured at increments of 4 ATM, 10 ATM, and burst pressure. Balloons were tested in triplicate for each load. RESULTS: All balloons were unable to reach 90% of their expected diameter with larger constrictive loads (122g) at low (4 ATM) and nominal (10 ATM) inflation pressures. Only the Bard and Cook balloons reached at least 90% of the expected diameter with a coefficient of variance (CV) less than 10% at burst pressure under the larger constrictive load (122g), 94.3% ± 6.7%, CV 7.1% and 96.3% ± 2.9%, CV 3.0% respectively. All balloons performed well under low constriction forces and reached at least 80% of the expected diameter by 10 ATM under all constrictive loads. CONCLUSIONS: The Bard X-Force and Cook Ultraxx percutaneous nephrostomy balloons achieved the most reliable radial dilation against large constrictive forces simulating fascial or retroperitoneal scar tissue

Ureteral Obstruction: Is the Full Metallic Double-Pigtail Stent the Way to Go?

Background: 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. Objective: The current study aims to determine short-and medium-term effectiveness of the Resonance stent in malignant and benign ureteral obstruction. Design, setting, and participants: In total, 50 patients with extrinsic malignant obstruction (n = 25), benign ureteral obstruction (n = 18), and previously obstructed mesh metal stents (n = 7) were prospectively evaluated. Intervention: All patients were treated by Resonance stent insertion. Twenty stents were inserted in antegrade fashion, and the remaining stents were inserted in a retrograde approach. No patient dropped out of the study. The follow-up evaluation included biochemical and imaging modalities. Measurements: We evaluated the technical success rate, stricture patency rate, complications, and the presence and type of encrustation. Results and limitations: The technical success rate of transversal and stenting of the strictures was 100%. In 19 patients, balloon dilatation was performed prior to stenting. The mean follow-up period was 8.5 mo. The stricture patency rate in patients with extrinsic malignant ureteral obstruction was 100% and in patients with benign ureteral obstruction 44%. Failure of Resonance stents in all cases of obstructed metal stents was observed shortly after the procedure (2-12 d). In nine cases, stent exchange was demanding. Encrustation was present in 12 out of 54 stents. Conclusions: The Resonance stent provides safe and sufficient management of malignant extrinsic ureteral obstruction. Resonance stent use in benign disease needs further evaluation, considering the untoward results of the present study. (C) 2009 European Association of Urology. Published by Elsevier B. V. All rights reserved

Randomized prospective evaluation of nephrostomy tube configuration: impact on postoperative pain

OBJECTIVE: Conduct a prospective randomized single-blind comparison of two nephrostomy catheter designs, evaluating specifically intraoperative placement and postoperative comfort. MATERIALS AND METHODS: The single-blind, prospective randomized trial was conducted with institutional review board approval. All patients undergoing percutaneous nephrolithotomy who gave informed consent were randomized to placement of either a Boston Scientific Flexima 8.3F pigtail nephrostomy tube #27-180 (PIG) or a Boston Scientific 8.2F nephroureteral stent #410-126 (NUS). Randomization was concealed from the surgeon until time of placement. Subjective intraoperative placement characteristics were rated by the surgeon on a scale of 1 = excellent, 2 = fair, 3 = good and 4 = poor. The patient's postoperative pain intensity was evaluated with a Visual Analog Pain Score (0 = no pain to 10 = worst pain). RESULTS: Nine patients were randomized to each group. The PIG group was rated significantly better than the NUS group with regards to ease of placement (p = 0.007) and radiopacity of the tube (p = 0.007) by surgeon. Visual analog pain scores on postoperative day one, was significantly lower in the PIG group (mean = 2+/-2) than the NUS group (mean = 5+/-1) (p = 0.004). The mean amount of intra-venous morphine equivalent given in the PIG group (mean = 1+/4 Eq morphine) was less on average compared to the NUS group (mean = 6+/13 Eq morphine), but the differences did not reach statistical significance (p = 0.06). CONCLUSIONS: Following percutaneous nephrolithotomy, use of a small pig-tail nephrostomy tube results in greater ease of placement and less postoperative pain than a nephroureteral catheter