Management of cystinuric patients: an observational, retrospective, single-centre analysis.

OBJECTIVE: A critical appraisal of the management of patients with cystine stones treated in our unit in the past 6 years and to analyze the outcome of multimodality therapies. STUDY DESIGN: An observational, single-centre retrospective study. METHODS: We reviewed the records of all patients with stones referred to our centre over a 6-year period from 1998 to 2005. Data recorded included demographic details, medical therapies received/prescribed, compliance with medical therapies, mode of treatment, stone clearance and any recurrence during this period of study. RESULTS: A total of 30 cystinuric patients were treated in our institution over the period of 6 years from 1998 to early 2005. Of these 16 were males and 14 females with an average age at last follow-up of 39 years (range 15-70). Two patients were successfully managed medically. The remaining patients (n = 28) underwent a total of 237 procedures (pre- and postreferral to our unit), with an average of 7.9 procedures per patient for 126 stone episodes (4.2 episodes/patient). The modes of treatment included extracorporeal shockwave lithotripsy (n = 143), ureterorenoscopy and intracorporeal lithotripsy (n = 50), percutaneous nephrolithotomy (n = 28) and open procedures (n = 16). Two patients needed open surgery at our unit. Prior to referral to our dedicated unit, patients had received treatment with extracorporeal shockwave lithotripsy (multiple sessions), ureteroscopy (n = 14), percutaneous nephrolithotomy (n = 4) and open stone removal (n = 14). Most of the stones at our unit were managed using minimally invasive therapies. CONCLUSION: Compliance of cystinuric patients with medical treatment is often poor and patients experience recurrent stone episodes requiring multiple interventions. Modern management of cystine calculi should be with staged minimally invasive procedures to avoid the complications of multiple open procedures wherever possible along with appropriate medical prophylaxis.

A randomized controlled trial of human versus robotic and telerobotic access to the kidney as the first step in percutaneous nephrolithotomy.

OBJECTIVE: We present results from the first randomized controlled trial of human vs. telerobotic access to the kidney during percutaneous nephrolithotomy. METHODS: To compare (a) human with robotic percutaneous needle access and (b) local robotic with trans-Atlantic robotic percutaneous needle access, we used a validated kidney model into which a needle was inserted 304 times. Half the insertions were performed by a robotic arm and the other half by urological surgeons. Order was decided randomly except for a sub-group of 30 trans-Atlantic robotic procedures that were controlled by a team at Johns Hopkins, Baltimore, via four ISDN lines. RESULTS: All attempts were successful within three passes with a median time of 35 s for human attempts compared with a median of 57 s for robotic attempts. The robot was slower than the human to complete insertions (p < 0.001, Mann-Whitney U test), but was more accurate when compared with human operators as it made fewer attempts (88% robotic vs. 79% human first attempt success; p = 0.046, chi-squared test). Times for trans-Atlantic robotic needle insertion (median = 59 s) were comparable to times taken for local robotic needle insertion (median = 56 s) with no difference in accuracy. CONCLUSION: Telerobotics is an accurate and feasible tool for future minimally invasive surgery.

Multimodal management of urolithiasis in renal transplantation.

OBJECTIVE: To report the largest single series of renal transplant patients (adults and children) with urolithiasis, assess the risk factors associated with urolithiasis in renal transplant recipients, and report the outcome of the multimodal management by endourological and open procedures. PATIENTS AND METHODS: The records of all patients undergoing renal transplantation between 1977 and 2003 were reviewed. In all, 2085 patients had a renal transplant at our centre and 21 (17 adults and four children) developed urinary tract calculi. Their mode of presentation, investigations, treatments, complications and outcomes were recorded. Investigations included one or more of the following; ultrasonography (US), plain abdominal X-ray, intravenous urography, nephrostogram and computed tomography. Management of these calculi involved extracorporeal shock wave lithotripsy (ESWL), flexible ureteroscopy and in situ lithotripsy, percutaneous nephrolithotomy (PCNL), open pyelolithotomy and open cystolitholapaxy. RESULTS: Thirteen patients had renal calculi, seven had ureteric calculi and one had bladder calculi. The incidence of urolithiasis was 21/2085 (1.01%) in the series. Urolithiasis was incidentally discovered on routine US in six patients, six presented with oliguria or anuria, including one with acute renal failure, four with a painful graft, three with haematuria, one with sepsis secondary to obstruction and infection and in one, urolithiasis was found after failure to remove a stent. Ten patients (63%) had an identifiable metabolic cause for urolithiasis, two by obstruction, two stent-related, one secondary to infection and in six no cause was identifiable. Thirteen required more than one treatment method; 13 (69%) were treated by ESWL, eight of whom required multiple sessions; eight required ureteric stent insertion before a second procedure and four required a nephrostomy tube to relieve obstruction. Two patients had flexible ureteroscopy and stone extraction, three had a PCNL and one had open cystolithotomy. PCNL failed in one patient who subsequently had successful open pyelolithotomy. All patients were rendered stone-free when different treatments were combined. CONCLUSIONS: The incidence of urolithiasis in renal transplant patients is low. There is a high incidence of metabolic causes and therefore renal transplant patients with urolithiasis should undergo comprehensive metabolic screening. Management of these patients requires a multidisciplinary approach by renal physicians, transplant surgeons and urologists.

Defining the learning curve for percutaneous nephrolithotomy.

PURPOSE: To define the learning curve for percutaneous nephrolithotomy (PCNL) using three potential surrogate markers of surgical expertise. MATERIALS AND METHODS: The learning curve of an endourologist with no previous experience at performing solo PCNL was studied. Three putative parameters of expertise were reviewed, namely, operating time, fluoroscopic screening time, and radiation dose. Operations were analyzed in cohorts of 15 to determine when a plateau was reached for all three variables. Comparison was then made with the results of a surgeon who had performed more than 1600 PCNLs. Stone type and stone clearance rate were also noted. RESULTS: The mean operating time of the novice surgeon fell to a plateau of 92 minutes after 60 cases, but screening time and radiation dose did not plateau until case 115, when values of 231 seconds and 406 cGy/cm2 were recorded, respectively. The senior surgeon had a mean operating time of 98 minutes and screening parameters equivalent to those of the novice surgeon after 115 cases. The complexity of the stones tackled grew with increasing experience, although stone-free rates remained constant. CONCLUSIONS: This study of the learning curve of a single surgeon suggests that competence at performing PCNL is reached after 60 cases and excellence after 115. Radiation parameters are a valuable tool in the assessment of operative competence.

Treatment of urolithiasis in the morbidly obese.

BACKGROUND: Morbidly obese patients with urolithiasis present a therapeutic and diagnostic challenge to the Urologist. Management is reported and potential difficulties discussed. METHODS: Morbidly obese patients (body mass index > or = 40kg/m2) with stone disease were identified by retrospective review. Stone load was calculated and treatment modalities noted. RESULTS: 18 renal units (kidneys) were treated in 17 patients. Of these, 2 required no treatment, 2 had open procedures, and 15 were treated with flexible ureteroscopy. Mean stone burden in patients treated with flexible ureteroscopy was 18 mm, but 8 patients had stone loads >15 mm and in these patients mean stone burden was 23 mm. All were successfully treated or rendered asymptomatic. There were no major complications. CONCLUSION: Obesity is increasingly prevalent and associated with a high incidence of co-morbidity and complications. Imaging can be difficult and treatment options are limited. Flexible ureteroscopy has proven to be the most successful treatment option, and can avoid the need for more invasive procedures. Furthermore, stone loads greater than normally acceptable can be successfully undertaken in these patients, and should be attempted due to problems associated with other techniques.

Management of encrusted ureteral stents impacted in upper tract.

OBJECTIVES: To present our series of patients with ureteral stent encrustation and give indwelling times and management. Encrustation is one of the most serious complications of ureteral stents. METHODS: A retrospective review was undertaken of all encrusted stents during a 4-year period. The inclusion criterion was a stent that required some form of intervention above the ureteral orifice to remove it. Combinations of extracorporeal shock wave lithotripsy, ureteroscopy, percutaneous nephrolithotomy, and open surgery were used to achieve stent removal. RESULTS: Forty-nine impacted encrusted stents were treated in 41 patients. Of these, 75.5% had become encrusted within 6 months and 42.8% within 4 months. The mean indwelling time was 5.6 months. Forty-seven stents were removed by endourologic techniques, with 4 requiring extracorporeal shock wave lithotripsy alone, 28 ureteroscopy, and 10 a combination of both. Five patients underwent successful percutaneous nephrolithotomy. One patient underwent open surgery, and in one removal failed. The mean number of procedures per patient was 1.94. CONCLUSIONS: Stent encrustation can pose a serious challenge to the endourologist, and indwelling times should be minimized to avoid problems. Patients often require multiple treatments and a combination of extracorporeal shock wave lithotripsy and ureteroscopy offers highly successful outcomes and often avoids the need for more invasive techniques.