Amplatz Dilators Research Articles

Previous Open Nephrolithotomy: Does It Affect Percutaneous Nephrolithotomy Techniques and Outcome?

The consequences of open nephrolithotomy are scar tissue around the kidney and in the retroperitoneum and distortion of the pelvicaliceal anatomy that may affect the techniques and outcome of percutaneous nephrolithotomy (PCNL). We compared the results and complications of patients undergoing PCNL who had and had not previously undergone open nephrolithotomy. A total of 178 calculi in 175 patients who had previously had open nephrolithotomy (group I) and 178 calculi in 175 patients who had never had a renal operation (group II) were treated with PCNL. The average time between open nephrolithotomy and PCNL was 8.5 years (range 4 months-22 years). In both groups, PCNL was done by a standard technique with serial Amplatz dilator enlargement of the tract to 30F. Upper-pole access under fluoroscopic guidance was done in most patients. The operative time, success rate, hospital stay, and complications in the two groups were compared. The stone-free rates were 80.3% and 82.6% in groups I and II, respectively, and the rate of residual fragments < or =4 mm was 14.6% and 8.4%. The operative time, success rate, hospital stay, and complications did not differ significantly in the two groups. Percutaneous nephrolithotomy is effective and safe in patients who have previously had open nephrolithotomy with no more complications than are seen with PCNL of kidneys that have not been operated on.

One-step percutaneous nephrolithotomy sheath versus standard two-step technique

Objectives Advances in technique and equipment have allowed urologists to perform percutaneous stone removal with increasing efficacy and decreasing complications. The procedure of choice for large renal calculi is percutaneous nephrolithotomy. At our institution, percutaneous access is achieved by a two-step process using either Amplatz dilators or placement of a high-pressure balloon catheter for tract dilation, followed by advancement of a sheath over the balloon. A novel device, the Pathway Access Sheath (PAS) has been developed that allows for balloon tract dilation and percutaneous access sheath placement in one simple step. Methods Our study population consisted of 21 patients, who were randomized to one of two arms. Of the 21 patients, 10 underwent standard two-step access using a high-pressure balloon catheter and 11 underwent percutaneous nephrolithotomy using the novel PAS. We compared the insertion time, blood loss, and cost between the two techniques. Results The average insertion time was shorter in the PAS group (3 minutes) compared with the high-pressure balloon catheter (5 minutes, 42 seconds); a difference that was statistically significant ( P <0.01). The estimated blood loss and cost were similar between the two groups. The increased sheath flexibility of the PAS was noted to be an advantage in some patients. Conclusions The results of our study have shown that a novel single-step renal access device is safe and efficacious and results in a shorter insertion time for percutaneous nephrolithotomy. Blood loss was less in the PAS group as well, although the difference was not statistically significant. Additional studies will establish whether this device will provide a new standard of obtaining renal access.

Failed percutaneous balloon dilation for renal access: Incidence and risk factors

Objectives To present our experience using balloon dilation and discuss secondary techniques to establish a percutaneous tract when balloon dilation fails. Balloon dilation is a safe and effective method to achieve percutaneous renal access, but it is not uniformly successful. Also, the failure rate and risk factors have not been well documented. Methods We retrospectively reviewed our last 99 consecutive percutaneous renal procedures using a balloon system as our initial dilation modality. In all cases, the urologist achieved needle access. We determined the balloon failure rate, relationship to prior renal surgery and other patient-related factors, and success rate using secondary techniques of tract dilation. Results The balloon did not adequately dilate a tract in 17 (17% failure rate) of 99 cases. The risk factors for failure included a history of prior ipsilateral renal surgery (25% failure rate versus 8% without surgery) and subcostal compared with supracostal puncture (18% versus 9% failure rate). The failure rate was not increased when stratified by laterality, stone composition, stone size and location, or history of ipsilateral renal infection. Amplatz dilators were used in 16 refractory cases and were successful in 15. Metal Alken dilators were successfully used in 2 patients. Conclusions The balloon dilation system is commonly used as the primary modality to establish percutaneous renal access. Although safe and effective (83%), the success rate drops dramatically in patients with prior ipsilateral renal surgery. Knowledge and skill with alternative dilation systems, such as Amplatz or metal Alken dilators, are necessary to successfully gain entry into all renal collecting systems.

Nephrostomy Tract Dilation Using a Balloon Dilator in Percutaneous Renal Surgery: Experience with 95 Cases and Comparison with the Fascial Dilator System

Introduction: Nephrostomy tract dilation is one of the important steps of percutaneous renal surgery. In this study, we present our initial experience with the balloon dilator in 95 patients and compare our results retrospectively with a group of 30 patients in whom Amplatz dilators were used. Patients and Methods: The medical records of 95 patients who underwent percutaneous renal operations, including percutaneous nephrolithotomy and antegrade endopyelotomy, between September 1999 and September 2002 were reviewed. All procedures were performed using balloon dilators. The operative technique is the same as the other dilation procedures. Thirty consecutive patients who had previously undergone percutaneous renal surgery using the Amplatz dilators were taken as the control group and their charts were reviewed retrospectively, and the results compared with the results of patients in whom balloon dilation was used. Results: There were no major perioperative complications or deaths in both groups. The mean operative time and tract formation times for the balloon dilation group and the Amplatz dilation group were 106.8 ± 41.4 and 11.2 ± 3.0, and 116.4 ± 23.7 and 16.3 ± 2.4 min, respectively. Thirteen (13.7%) patients had significant bleeding and required blood transfusion in the balloon dilation group, whereas 5 (16.6%) patients had significant bleeding in the Amplatz dilation group. Collecting system perforation due to too far advancement of the dilator occurred in 11 (11.6%) patients but there was no major parenchymal or vascular injury medially in the balloon dilation group. On the other hand, collecting system perforation occurred during sequential Amplatz dilation in 5 (16.6%) patients. Conclusion: We believe that the balloon system allows one-step dilation and shortens the dilation procedure. It may minimize bleeding which can occur during the stepwise fascial dilation. When using fascial dilators it is sometimes possible to go out of the collecting system by changing the size of the dilators. We think that balloon dilation may prevent these intraoperative and time-consuming situations.

Radially expanding single-step nephrostomy tract dilator

Objectives. To compare the radial and axial forces produced by balloon, Amplatz, and radially expanding single-step nephrostomy (RESN) systems and report our initial clinical results using the new RESN device. Balloon, Amplatz, and Alken dilators are commonly used to establish nephrostomy tracts in percutaneous surgery. They require multiple steps, with the potential for kinking and displacement of the working guidewire. In contrast, the new RESN tract dilator expands a unique sleeve conduit and places an Amplatz-like sheath in a single step with less dependence on a guidewire for dilation. Methods. An experimental model was designed using a perforated silicon disc with a 10F central opening to measure the axial force transmission as 30F balloon, Amplatz, and RESN systems were inserted through the silicon discs. We also report our first 9 patients who underwent percutaneous dilation with the RESN system. Results. Thirty French expansion was achieved with each dilator tested. Substantially lower axial forces were transmitted with the RESN device compared with the balloon and Amplatz dilators (5.2 versus 13.1 and 19.2 lb, respectively, P <0.001). Intraoperatively, all 9 patients were successfully dilated, and the kidney was relatively stationary as imaged with fluoroscopy. One patient with multiple prior renal procedures was successfully dilated with RESN system after failed attempts with balloon dilation. Conclusions. The RESN dilator is a rapid, single-step access system successfully used in our first 9 patients. Intraluminal sleeve dilation eliminates guidewire dependence for maintaining access, limits renal displacement, and facilitates appropriate vector force for percutaneous dilation.

Percutaneous nephrolithotomy in older children

Purpose: The aim of this study was to evaluate the safety and efficacy of percutaneous nephrolithotomy (PCNL) in pediatric patients, older than 8 years, without any technical and instrumental modifications. Methods: The authors retrospectively evaluated the data of 16 percutaneously treated kidneys of 14 patients with a mean age of 11 years (range, 8 to 17). The mean stone burden was calculated as 301 mm2 (range, 120-750). Percutaneous accesses were done under fluoroscopic control, and 24F to 30F Amplatz dilators were used depending on patient size. Ultrasonic and laser lithotripsy were performed to fragment calculi. Results: Mean operating time was 111 minutes (range, 60 to 210 min) and no intraoperative or postoperative major complication was observed. Mean hemoglobin drop after the procedure was 1.16 g/dL (range, 0.3 to 2.8). Blood transfusion was required in only 1 patient, and mean postoperative hospitalization was 4.6 days (range, 3 to 10). Stone-free rate was calculated as 69% (11 of 16), but with residual fragments smaller than 4 mm, the success rate becomes 100% at patient's discharge. Conclusions: PCNL is an effective and safe form of therapy in pediatric stone disease. Especially in older children the use of the same instruments and technique as in adults may achieve equal results without any increased risk of possible morbidity and need of blood transfusion. J Pediatr Surg 35:1336-1338. Copyright © 2000 by W.B. Saunders Company.

ORCHIOPEXY USING 2 MM. LAPAROSCOPIC INSTRUMENTS:2 TECHNIQUES FOR DELIVERING THE TESTIS INTO THE SCROTUM

We describe modified techniques of laparoscopic orchiopexy using 2 mm. instruments that enable straightforward delivery of the testis into the scrotum. The preferred technique involves a radially dilating trocar advanced over the 2 mm. grasper placed antegrade through the new internal ring. The other method is similar but Amplatz dilators are used when a radially dilating trocar system is not available. We used these techniques with complete success to deliver 18 testes into the scrotum. The testis may be safely and effectively delivered to the scrotum using 2 mm. instruments and disposable fascial dilators or a radially dilating trocar system.

New technique for antegrade collagen injection for post-radical prostatectomy stress urinary incontinence

A new modification for antegrade collagen injection into the bladder neck is described. A 16F Rusch suprapubic catheter is used to access the bladder. A 15.5F Storz cystoscope is then placed through the sheath and the collagen injection needle is then placed through the cystoscope in the usual manner. This technique permits more rapid bladder access with less bleeding and leakage of irrigation fluid than using guide wires and Amplatz dilators.

Influence of Technique of Percutaneous Tract Creation on Incidence of Renal Hemorrhage

Renal hemorrhage is one of the most common and worrisome complications of percutaneous renal surgery. We studied the incidence of renal hemorrhage and transfusion rates in patients undergoing balloon or Amplatz fascial dilation of the nephrostomy tract. Medical records of 143 patients who underwent 150 percutaneous renal procedures, including percutaneous nephrolithotomy, antegrade endopyelotomy and percutaneous treatment of stones in caliceal diverticula, were reviewed. The nephrostomy tract was dilated with balloon (50 patients) or Amplatz sequential (100) dilators. Perioperative decreases in hemoglobin level and blood transfusion rates were compared between the 2 groups. Of the 100 patients undergoing percutaneous renal Amplatz dilation 25 (25%) required a blood transfusion, compared to only 5 of 50 (10%) undergoing balloon dilation. The difference in the transfusion rates between the 2 groups was statistically significant (p = 0.048). Improvements in the technique of percutaneous renal surgery have decreased the morbidity associated with these procedures. In our study use of balloon tract dilators led to less renal hemorrhage and lower transfusion rates compared to Amplatz dilation. Additionally, balloon dilation appears to be more rapid and avoids renal movement away from the surgeon, which occasionally occurs during Amplatz dilation.

Suprapubic Percutaneous Cystolitholapaxy in Children

Bladder stones of 10 male children were removed via the percutaneous suprapubic route. The mean age was 3.5 years, and the mean stone size was 1.2 cm. As in the percutaneous nephrolithotomy technique, the bladder was punctured under fluoroscopy followed by tract dilation to 32F using Amplatz dilators and sheath. Then the bladder stones were inspected and removed with an adult nephroscope. A 1-day hospital stay was recorded for all patients with no morbidity or deaths.

Percutaneous Nephrostomy Tract Incision Using Modified Otis Urethrotome

An Otis urethrotome has been modified to permit passage into the kidney over an 0.038-inch guidewire by drilling a 3/16-inch hole through the tip. I have used this instrument to aid in the performance of 36 nephrostomy tract dilations without significant complications. When compared with 20 Amplatz tract nephrostomy dilations, the new method was quicker, requiring 4.3 minutes versus 6.5 minutes. This instrument is especially useful for tracts where significant renal fascial scarring makes Amplatz dilation difficult. Ease of tract dilation, as well as decreased time to dilate, make this technique a useful addition to standard nephrostomy tract dilation techniques.

Split 24-F Amplatz dilator for percutaneous extraction of an intravascular bullet: case report and technical note.

An intravascular bullet was retrieved percutaneously in a 17-year-old boy with the use of a modified 24-F Amplatz dilator. The dilator was modified by means of a longitudinal incision with removal of a wedge at the distal tip of the tapered portion of the dilator. The bullet, which was located in the left pulmonary artery, was removed via the right femoral vein. No complications occurred.