Biomedical subjects

Richard Tiptaft

Publications and source records attributed to Richard Tiptaft.

3 recordsLinked to original sources

PubMed2005

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.

Clinical Competence↗

PubMed2005

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.

Adolescent↗

PubMed2005

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.

Clinical Competence↗