Biomedical subjects
Publications and source records attributed to Michael E Moran.
Pheochromocytomas can present with profound, life-threatening conditions, such as hypertension, fever, and rarely with a host of clinical conditions producing a multisystem crisis. We report a case of this syndrome and comment on clinical management.
PURPOSE: We externally validated a previously designed neural network model to predict outcome and duration of passage for ureteral/renal calculi. The model was also evaluated using a 6 mm largest stone dimension cutoff in predicting stone outcome. MATERIALS AND METHODS: The model was previously designed on 301 patients at Albany Medical Center (free shareware from www.uroengineering.com). The model had a prediction accuracy of 86% for passage outcome and 87% for passage duration. In this study we tested the model on a separate 384 patients from 6 different external institutions to assess the prediction accuracy. All patients had a single renal/ureteral calculus by evaluation in an emergency room setting or by primary physicians and were then referred for further treatment. Model accuracy was also compared to using a 6 mm largest stone dimension cutoff in predicting the need for intervention. RESULTS: Testing on the 384 patients from all 6 external institutions revealed an outcome prediction accuracy of 88%. The area under the ROC curve was 0.9. Using a 6 mm stone size cutoff provided 79% (ROC 0.8) accuracy. The model duration of passage prediction accuracy was 80% (133 patients passed the stone, area under ROC of 0.8). CONCLUSIONS: The model provided high stone outcome prediction accuracy (ROC of 0.9 and 0.8) at the 6 external institutions, comparable to that of the design institution. The model provided higher accuracy than using only the largest stone dimension as a cutoff. Increasing experience will further assess the model's accuracy.
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BACKGROUND: Sir William Osler published his textbook, The Principles and Practice of Medicine, in 1892. It became the definitive treatise on a wide variety of diseases. The section on nephrolithiasis clearly presents the etiology, pathology, symptoms, diagnosis, and treatments. What remains a mystery is the mention, under rare forms of human stones, of a type called "indigo." MATERIALS AND METHODS: A search of Index Medicus starting from 1909 backward to its inception in 1879 was performed for key words "indigo," "calculus," "renal" or "bladder stones" and "indicanuria." Twelve textbooks of urology published before 1940 were scrutinized for references to indigo calculi. RESULTS: Only two references to indigo were found, both related to its use for treating constipation (1887 and 1891). Of the 12 textbooks, only 4 make passing reference to "indigo stones." They all mention that such calculi are very rare, but direct references to cases are lacking. One textbook references a study of blue stones from Egyptian mummies. CONCLUSION: It is unlikely that Osler's reference to an indigo calculus was taken lightly during his writing of The Principles and Practice of Medicine. The case of the indigo calculus is fascinating and perhaps enlightening if only for the source of Osler's intrigue.
The advances of technology are having substantial ramifications in medicine and in urology, in particular. This article discusses these advances and explores current trends in ureteroscopy.
Laparoscopic surgeons have made significant efforts to minimize the trauma induced by their procedures. One of the newest methods is the use of mini and micro instruments. This work is reviewed here.
PURPOSE: We developed a computer model to predict the outcome and the duration until passage of ureteral/renal calculi. MATERIALS AND METHODS: A retrospective, randomized study was performed of the outcome in 301 patients presenting to the emergency room for renal colic. Presenting characteristics of those diagnosed with a single calculus by computerized tomography were recorded for analysis. Predictors of stone passage and passage duration were identified and then used to create a logistic regression model. The algorithm was trained on 141 randomly selected patients and then tested on a separate 160 patients. Model accuracy was compared to predictions from 10 experienced urologists and 9 urology residents in 77 randomly selected patients. The model was tested further in 30 randomly selected patients at a private hospital to assess its general applicability. RESULTS: The model prediction accuracy in 160 patients was 86.3% for passage and 87.3% for duration (less or greater than 2 weeks). In the comparison group the model, the 10 experienced urologists and the 9 urology residents had an overall prediction accuracy of 88.3%, 70.5% (p = 0.006) and 72% (p = 0.007) for passage, and 87.1%, 71.6% (p = 0.007) and 81% (p = 0.075) for duration, respectively. Prediction accuracy was 93.3% for passage and 90.3% for duration when tested at a private hospital. CONCLUSIONS: Our model provides outcome and duration of passage predictions for patients presenting acutely in the emergency room with a single ureteral/renal calculus. It performs better than experienced urologists and urology residents. It can be applied to a private practice setting with equal accuracy.
The trend in uric acid stone formation appears to be on the rise again throughout much of the world. This is thought secondary to diet, body habitus, and social reasons. Uric acid stone disease has a rich and fascinating medical history and probably is the oldest known stone disease. Uric acid stone disease is strongly linked to the purine metabolic pathway, and its treatment is primarily medical. Uric acid stone disease can be prevented and these are one of the few urinary tract stones that can be dissolved successfully. Surgical intervention with uric acid stone disease represents a failure of medical therapy and a whole host of modern, minimally invasive methods are available for treating patients with this disease. Finally, uric acid nephrolithiasis is associated with a variety of inborn errors of metabolism based on mutations of key enzymes in the purine metabolic pathways. This review of uric acid stone formation will start with historical consideration, review basic biochemistry, and physiology and then focus upon specific clinical scenarios. The discussions will be heavily referenced for those interested in greater details.
BACKGROUND AND PURPOSE: Laparoscopic radical nephrectomy is a minimally invasive alternative to open radical nephrectomy. We have noticed that since the beginning of 2001, when the Current Procedural Terminology (CPT) code 50545 became available for laparoscopic nephrectomy, the reimbursement for the laparoscopic operation was significantly lowered. This led us to survey 25 laparoscopic urologic surgeons to assess trends in reimbursement from all over the United States. MATERIALS AND METHODS: During this period, the records of reimbursements for radical nephrectomy were available from a single practice to compare that for the open and laparoscopic techniques. The 19 open and 10 laparoscopic operations were entered in a database for statistical analysis. Endourologists around the country also were polled on the subject. RESULTS: The average reimbursement for an open radical nephrectomy was $1581 +/- 325 (SD), while the average reimbursement for a laparoscopic radical nephrectomy was $1192 +/- 184. Twenty-five polled endourologists had noted similar reductions in reimbursement for laparoscopic procedures. Many of those polled had participated in the Specialty Society Relative Value Unit (RVU) survey for laparoscopic radical nephrectomy and stated that their recommendations were that the value be considered greater than that of the open counterpart. CONCLUSION: The highly significant difference in reimbursement reflects a financial disincentive to surgeons performing laparoscopic procedures. It is obvious that in the U.S., the Health Care Financing Administration (now the Centers for Medicare and Medicaid Services) is devaluating all surgical procedures, and financial pressures of this type are disturbing.
Current medical robots have nothing in common with the anthropomorphic robots in science fiction classics. They are in fact, manipulators, working on a master-slave principle. Robots can be defined as "automatically controlled multitask manipulators, which are freely programmable in three or more spaces." The success of robots in surgery is based on their precision, lack of fatigue, and speed of action. This review describes the theory, advantages, disadvantages, and clinical utilization of mechanical and robotic arm systems to replace the second assistant and provide camera direction and stability during laparoscopic surgery. The Robotrac system (Aesculap, Burlingame, CA), the First Assistant (Leonard Medical Inc, Huntingdon Valley, PA), AESOP (Computer Motion, Goleta, CA), ZEUS (Computer Motion), and the da Vinci (Intuitive Surgical, Mountain View, CA) system are reviewed, as are simple mechanical-assist systems such as Omnitract (Minnesota Scientific, St. Paul, MN), Iron Intern (Automated Medical Products Corp., New York, NY), the Bookwalter retraction system (Codman , Somerville, NJ), the Surgassistant trade mark (Solos Endoscopy, Irvine, CA), the Trocar Sleeve Stabilizer (Richard Wolf Medical Instruments Corp., Rosemont, IL), and the Endoholder (Codman, Somerville, NJ).
OBJECTIVES: Uric acid stones are best managed by chemolysis. Some patients with acutely symptomatic stones opt for endourologic therapies. The radiolucent nature of these stones makes secondary interventions difficult to plan. Computed tomography becomes the modality of choice to identify stone locations and size in these patients. We analyzed patients with uric acid stones referred to our stone center after primary treatment had failed to establish the efficacy of oral alkalinization therapy. METHODS: Eleven patients presented after one or more failed attempts to intervene for uric acid stones. Charts were reviewed for age, sex, time with stone before referral, medical therapies undertaken, number of antecedent urologic interventions, number of radiographic studies performed, subsequent procedures performed, and outcomes with a minimal follow-up of 6 months. RESULTS: Eight patients were men and four presented with bilateral stone disease (overall, 15 involved upper tracts). Sixty-seven percent of patients had right-sided solitary calculi. All patients at presentation filled out urinary pH diaries. Of the 11 patients, 4 stated they had been prescribed oral alkaline therapy but were found to be noncompliant, 4 were never prescribed this therapy, and 3 took the medication sporadically. All patients were counseled on self-dosing to maintain their urinary pH between 6.0 and 6.5 and to continue the diaries. Computed tomography scans were done in 9 patients, and intravenous urography and ultrasonography in the other 2 patients confirmed the stone burden. Only 3 patients (27%) required subsequent interventions (ureteroscopic laser lithotripsy). CONCLUSIONS: Secondarily referred patients with uric acid stones are best treated with medical therapy. These findings suggest that the initial medical regimens had failed because of noncompliance or lack of effective follow-up by the primary urologist. Seventy-three percent of these patients had dissolution of the stones, requiring no further endourologic intervention.
Topiramate is a recently developed antiepileptic medication that is becoming more widely prescribed because of its efficacy in treating refractory seizures. Urologists should be aware that this medication can cause metabolic acidosis in patients secondary to inhibition of carbonic anhydrase. In addition, a distal tubular acidification defect may result, thus impairing the normal compensatory drop in urine pH. These factors can lead to the development of calcium phosphate nephrolithiasis. We report the first two cases of topiramate-induced nephrolithiasis in the urologic literature.
The triad of cancer cure, rapid recovery of complete urinary continence, and preservation of sexual function are desirable in the contemporary surgical treatment of the young potent male with prostate cancer. Robotic prostatectomy is a Food and Drug Administration approved approach to radical prostatectomy, and is performed at our institution and elsewhere. We present a critical assessment of reported outcomes using this minimally invasive technique.