Biomedical subjects
R K Singal
Publications and source records attributed to R K Singal.
Percutaneous suprapubic cystolithotripsy for treatment of large bladder calculi.
BACKGROUND AND PURPOSE: The treatment options available for managing bladder calculi include transurethral cystolithotripsy, open cystolithotomy, and shockwave lithotripsy. For larger calculi, transurethral treatment can be time consuming, and the manipulation has the potential to cause urethral injury. Percutaneous suprapubic cystolithotripsy represents another treatment option for bladder calculi which is effective and minimally invasive. PATIENTS AND METHODS: Fifteen patients had bladder calculi treated with percutaneous cystolithotripsy over a 3-year period. The mean stone size was 39 mm (range 10-64 mm). Stones were single in seven patients and multiple in eight patients. The indications for cystolithotripsy were stone size >3 cm, multiple stones >1 cm, and inability to perform transurethral cystolithotripsy because of patient anatomy. Percutaneous suprapubic cystolithotripsy was done through either a 30F or a 36F cystotomy tract. Fragmentation and removal was performed with a 26F rigid nephroscope and the pneumatic Swiss Lithoclast. Suprapubic and urethral catheters were placed postoperatively in all patients. RESULTS: Each patient was cleared of the stone burden with a single procedure, and there were no major complications. The mean duration of suprapubic catheterization was 2.6 (range 1-5) days. CONCLUSION: Percutaneous suprapubic cystolithotripsy is an effective and safe technique for treating large bladder calculi. It is minimally invasive, avoids urethral injury, and, in combination with the pneumatic Swiss Lithoclast, can be used to fragment and remove large and hard bladder calculi.
Secondary ureteroscopy: results and management strategy at a referral center.
PURPOSE: In an era when extracorporeal shock wave lithotripsy occupies a dominant place in the treatment of urolithiasis ureteroscopy retains an important role in certain circumstances. While often a definitive procedure, ureteroscopy can be associated with potential risks and complications. The treatment of patients who have undergone a failed attempt at ureteroscopic stone retrieval or have a complication may be complex. As a tertiary care stone referral center we review our experience with performing salvage ureteroscopy following a previous unsuccessful attempt at endoscopic stone removal. MATERIALS AND METHODS: Between May 1990 and February 1996, 79 patients were referred following an unsuccessful attempt at retrograde endoscopic or basket manipulation for ureteral calculi. A retrospective review of the outcomes of these patients was conducted. Of the patients 11 presented with associated complications, which included ureteral perforation (4), intramural false passage (1) and fever or sepsis (6). Complications were managed by early establishment of urinary tract drainage by stenting or nephrostomy. Among patients without complications elective salvage ureteroscopy was performed. RESULTS: Ureteroscopy was used in 79 patients with a successful outcome (stone-free) in 75 (95%). Followup imaging with renal ultrasound or excretory urography at least 3 months after secondary ureteroscopy was available in 65 patients and showed no evidence of hydronephrosis or delayed stricture formation. CONCLUSIONS: Treating the patient who undergoes a failed attempt at ureteroscopy may be problematic and requires access to a wide array of endourological equipment. Each subsequent treatment should be individualized with consideration given to stone size, location and general health. In the presence of a ureteral injury establishment of early urinary tract drainage is essential. Following stabilization, secondary ureteroscopy can be performed yielding high stone-free rates with minimal complications.
Holmium:YAG laser endoureterotomy for treatment of ureteral stricture.
OBJECTIVES: Endourologic techniques ranging from balloon dilation to endoincision with electrocautery, cold knife, and lasers have been increasingly used in recent years for the treatment of ureteral strictures. While the long-term results may not be as reliable or as durable as traditional reconstructive surgical techniques, they can be accomplished with much less morbidity. Recently, the holmium:yttrium-aluminum-garnet (YAG) laser, which possesses both cutting and coagulating properties, has been demonstrated to have many applications in urology. We report our experience with this laser in the endoscopic treatment of ureteral strictures. METHODS: We reviewed the charts and follow-up history of 22 patients in whom the holmium:YAG laser was used to treat ureteral strictures from a variety of causes and including those in ureteroenteric anastomoses. Strictures were either approached in a retrograde fashion with a 6.9F ureteroscope or antegrade with flexible instruments in the cases involving ureteroenteric strictures. The only energy source employed was the laser, followed by balloon dilation. Indwelling stents were left in place for at least 4 weeks postoperatively and follow-up was obtained with radiographic imaging. RESULTS: A minimum 9-month follow-up was available for 18 patients. There were 5 patients who had developed recurrent strictures and were therefore considered treatment failures. Each of these patients failed in less than 3 months and all had either lengthy or complex strictures noted at the time of surgery. One patient was lost to follow-up and three recent patients have follow-up of 3 to 6 months showing no evidence of recurrent stricture formation. Overall, 16 of 21 (76%) patients are clinically well with no evidence of stricture recurrence. CONCLUSIONS: Endoureterotomy for ureteral stricture disease is a minimally invasive, less morbid, but ultimately less successful, alternative to open surgical reconstruction. Stricture length and etiology remain the most important determinants of success. The holmium:YAG laser, with its ability to precisely cut tissue and provide hemostasis and its multiuse potential and compatibility with small rigid and flexible endoscopic instruments, is an ideal tool for performing endoureterotomy.
Contemporary management of ureteral stones.
The management of ureteral stones has undergone revolutionary changes in the past 15 years. The parallel advances in extracorporeal shock wave lithotripsy, percutaneous and retrograde endoscopic access to the collecting system, and intracorporeal lithotripsy devices almost completely have supplanted the need for a traditional ureterolithotomy. The merits of the various technologies that are available are discussed as they apply to treating calculi in different ureteral segments.
Evaluation of Doppler ultrasonography and dynamic contrast-enhanced CT in acute and chronic renal obstruction.
The development of a reliable, minimally invasive method of distinguishing physiologically significant renal obstruction from dilation without obstruction would have important clinical implications. As it is well known that renal blood flow decreases over time in the presence of obstruction, we investigated the ability of color flow Doppler ultrasonography and dynamic contrast-enhanced CT scanning to detect changes in blood flow in unilaterally obstructed porcine kidneys. In the initial phase of this study, the effect of acute unilateral obstruction were studied in nine pigs. The resistive index (RI) was measured with Doppler ultrasonography, and renal blood flow was quantitated with dynamic CT using tracer kinetic principles and deconvolution. The RI measurements were unable to distinguish between the obstructed kidneys and their controls. Dynamic CT scanning demonstrated a greater fall in blood flow in the obstructed kidney, and this change was significantly different from baseline. The same findings were supported by radiolabelled microsphere blood-flow measurement. In the chronic portion of the study, after surgical creation of a partial ureteric obstruction, the kidneys were studied by both techniques at 1, 2, and 3 weeks. Again, RI was unable to demonstrate any difference between obstructed and unobstructed kidneys, while CT showed a progressive fall in blood flow in each successive week that was statistically significant. Dynamic contrast-enhanced CT scanning is a promising diagnostic tool that might be used to distinguish a functionally significant renal obstruction from nonobstructive dilation. Further clinical studies to validate this technique are warranted.
Evaluation of different rodenticidal baits against rodent population in cucumber (Cucumis sativus) crop fields.
The baits used consisted of 2% zinc phosphide and 0.005% bromadiolone. The baitings were carried out at the flowering stage of cucumber crop. Double baiting treatments comprising zinc phosphide and bromadiolone in different combinations resulted in better reduction of rodent population and crop damage. Deployment of different rodenticidal treatments saved yield loss from 7.00 to 11.82q/ha. Thus, accomplishing cost benefit ratio of 1:88 to 1:107. Bromadiolone followed by bromadiolone, the most profitable combination is suggested for control of rodent population in cucumber crop fields.