Marshall L. Stoller

Estimated Blood Loss and Transfusion Rates Associated with Percutaneous Nephrolithotomy

We analyzed retrospectively 127 percutaneous nephrolithotomies performed on 96 patients between 1986 and 1989 to estimate the average total blood loss from the procedure. Blood transfusions and a postoperative decrease in hemoglobin level were combined to estimate total blood loss. The average blood loss for uncomplicated 1-stage single puncture percutaneous nephrolithotomy was 2.8 gm./dl. hemoglobin. Factors potentially influencing blood loss were identified. Multiple punctures and/or renal pelvic perforation was associated with a 2-fold greater blood loss. Half of the expected blood loss occurred in patients with a preexisting nephrostomy tract. Calculus morphology, location, composition and length did not affect total blood loss, nor did the number of fragments or stone-containing calices. Other factors, such as puncture site, type of fascial dilation, hypertension, renal insufficiency, infection, previous open renal surgery or previous extracorporeal shock wave lithotripsy, also did not affect total estimated blood loss. During the study years the blood transfusion rate was 23% in all patients and 14% in those with a single puncture uncomplicated by renal pelvic perforation and without a mature nephrostomy tract. The only statistically significant risk factors influencing the likelihood of a blood transfusion were preoperative anemia and total blood loss. Although our current transfusion rate associated with percutaneous nephrolithotomy (4% in nonanemic patients from 1989 to 1992) is much lower, patients must be made aware of the likelihood of blood transfusion, and urologists should recognize the risk factors for blood loss and transfusion.

Natural history and current concepts for the treatment of small ureteral calculi.

Six studies providing information on 2,704 patients were included into a retrospective analysis. The incidence of spontaneous passage relating both stone size and location was determined from these collated studies. The rate of spontaneous passage for stones smaller than 4 mm was 38% compared to 1.2% for those larger than 6 mm, irrespective of their position in the ureter at the time of presentation. Calculi discovered in the distal third of the ureter had a spontaneous passage rate of 45%, compared with the mid third of 22%, and the proximal third of 12%. Two thirds of all stones which passed did so within 4 weeks after the onset of symptoms. These data from the literature were compared to the treatment modalities applied for the last 100 consecutive patients treated with the diagnosis of ureteral stone at UCSF. 42% of the stones were found in the proximal, 13% in the mid and 45% in the distal third of the ureter. Treatment modalities included ureteroscopic stone extraction (36), ESWL (31) and watchful waiting for stone passage (30). Oral litholysis was performed in 2 cases and percutaneous removal of a proximal stone in 1. No calculus larger than 6 mm passed spontaneously. The passage rate from the proximal ureter was 18%, from the mid ureter 15%, and 38% from the distal ureter disregarding the size of the stones. The rate of complications reached 20% when symptoms exceeded 4 weeks in duration compared to 7% in patients with symptoms lasting less than 4 weeks.(ABSTRACT TRUNCATED AT 250 WORDS)

Uric Acid Nephrolithiasis: Current Concepts and Controversies

PURPOSE Uric acid calculi with or without a calcium component comprise a significant proportion of urinary stones. Knowledge of the pathophysiology of stone formation is important to direct medical treatment. The aim of this review is to provide an update on the epidemiology, pathophysiology and management of uric acid renal stones. MATERIALS AND METHODS A MEDLINE search was performed on the topic of uric acid stones. Current literature was reviewed with regard to the epidemiology, pathophysiology, associated medical conditions and management of uric acid stones. RESULTS The incidence of uric acid stones varies between countries and accounts for 5% to 40% of all urinary calculi. Hyperuricuria, low urinary output and acidic urine are well known contributing factors. However, the most important factor for uric acid stone formation is persistently acidic urine. Gout and myeloproliferative disorders are associated with uric acid stones. Why most patients with gout present with acidic urine yet only 20% have uric acid stone formation remains unclear. The pathophysiological basis for persistent urine acidity also remains unclear although various mechanisms have been proposed. Urinary alkalization with potassium citrate or sodium bicarbonate is a highly effective treatment, resulting in dissolution of existing stones and prevention of recurrence. CONCLUSIONS Acidic urine is a prerequisite for uric acid stone formation and growth. Medical management with urinary alkalization for stone dissolution and prevention of recurrence is effective and should be the cornerstone of treatment.

Impact of body weight on urinary electrolytes in urinary stone formers

OBJECTIVES Obesity increases the risk of developing chronic medical conditions such as diabetes mellitus, hypertension, and coronary artery disease. We performed a retrospective review of a large data base on urinary stones to determine if differences are found in urine and serum chemistries among obese and nonobese stone-forming patients. The effect of body weight on stone recurrence among urinary stone formers was also determined. METHODS A national data base containing serum biochemical profiles, 24-hour urine specimens, and standardized questionnaires was retrospectively evaluated from 5942 consecutive patients with urinary stone disease. Stone-forming patients were classified by body weight: nonobese men, less than 100 kg and nonobese women, less than 85 kg; intermediate men, 100 to 120 kg and intermediate women, 85 to 100 kg; and obese men, more than 120 kg and obese women, more than 100 kg. RESULTS Obese stone formers comprised 6.8% (n = 404) of the patient population. The mean weight in the nonobese and obese groups was 81 kg versus 134 kg, respectively, for men and 64 kg versus 112 kg, respectively, for women. Obese patients represented 3.8% of the male and 12.6% of the female population. Obese patients had increased urinary excretion of sodium, calcium, magnesium, citrate, sulfate, phosphate, oxalate, uric acid, and cystine; obesity was associated with increased urinary volumes and urine osmolality compared with the nonobese patients. Obese men had increased concentration of urinary sodium, oxalate, uric acid, sulfate, and phosphate when corrected for urinary volume. Obese women had increased concentrations of sodium, uric acid, sulfate, phosphate, and cystine. The mean number of stone episodes in nonobese versus obese men was similar (3.55 and 3.56), whereas mean stone episodes were 2.93 and 3.38 (P = 0.045) for nonobese versus obese women. CONCLUSIONS Among known stone formers, obesity is associated with unique changes in both serum and urinary chemistries. These changes are associated with an increased incidence of urinary stone episodes in obese women but not in obese men.

Dietary Manipulation With Lemonade to Treat Hypocitraturic Calcium Nephrolithiasis

PURPOSE Pharmacological treatment of hypocitraturic calcium nephrolithiasis requires as many as 12 tablets, or numerous crystal packages or liquid supplements taken throughout the day. In addition to added cost, this cumbersome regimen decreases patient compliance, which may increase stone recurrence rates. We evaluated the urinary biochemical effects of dietary citrate supplementation in hypocitraturic calcium stone formers in an attempt to decrease or eliminate the need for pharmacological therapy. MATERIALS AND METHODS A total of 12 patients who were either noncompliant with or intolerant of pharmacological citrate therapy supplemented their routine diet with citrate in the form of lemonade, consisting of 4 ounces of reconstituted lemon juice (5.9 gm. citric acid) mixed with tap water to a total volume of 2 l. and consumed at uniform intervals throughout the day. Urine specimens (24-hour) were obtained for biochemical analysis after 6 days of lemonade therapy and compared to pre-lemonade baseline values. RESULTS Of the 12 patients 11 had increased urinary citrate levels during lemonade therapy (average 204 mg. per day). Average levels increased from 142 mg. daily (range less than 10 to 293) at baseline to 346 mg. daily (range 89 to 814) after treatment (p < 0.001). Daily total urinary volumes were similar (2.7 versus 2.9 l.). Seven of 12 patients became normocitraturic while consuming lemonade. Urinary calcium excretion decreased an average of 39 mg. daily, while oxalate excretion was unchanged. The lemonade mixture was well tolerated. Two patients complained of mild indigestion that did not require cessation of therapy. CONCLUSIONS Citrate supplementation with lemonade increased urinary citrate levels more than 2-fold without changing total urinary volume. Lemon juice, which contains nearly 5 times the concentration of citric acid compared to orange juice, is an inexpensive and well tolerated dietary source of citrate. Lemonade therapy may improve patient compliance, and may be useful as adjunctive treatment for patients with hypocitraturic calcium nephrolithiasis.

The vesical calculus.

Bladder calculi account for 5% of urinary calculi and usually occur because of foreign bodies, obstruction, or infection. Males with prostate disease or previous prostate surgery and women who undergo anti-incontinence surgery are at higher risk for developing bladder calculi. Patients with SCI with indwelling Foley catheters are at high risk for developing stones. There appears to be a significant association between bladder calculi and the formation of malignant bladder tumors in these patients. Transplant recipients are not at increased risk for developing vesical calculi in the absence of intravesical suture fragments and other foreign bodies. Patients who undergo bladder-augmentation procedures using a vascularized gastric patch appear to be protected from vesicolithiasis, perhaps by the acidic environment. Ileum and colon tissues, however, are colonized by urease-producing organisms, producing an alkaline pH that promotes stone formation. Children remain at high risk for bladder-stone development in endemic areas. Diet, voiding dysfunction, and uncorrected anatomic abnormalities, such as posterior urethral valves and vesicoureteral reflux, predispose them to bladder-calculus formation. Finally, there are a number of techniques and modalities available to remove bladder stones. Relieving obstruction, eliminating infection, meticulous surgical technique, and accurate diagnosis are essential in their treatment.

Ureteroscopy without Routine Balloon Dilation: An Outcome Assessment

A retrospective analysis of 156 rigid ureteroscopic stone procedures in 145 patients revealed successful manipulation in 90%. The stone-free rate after adjunctive procedures was 95%. Access was achieved without balloon dilation in all but 18 patients. There were 24 perforations, occurring in 31% of proximal, 8% of mid ureteral and 8% of distal stone manipulations. Of the evaluable patients 63% underwent radiographic assessment for stricture disease, 75% at 6 months or more after the procedure. The stricture rate was 3.5% in all patients and 5.9% in patients with perforations. Of 37 patients evaluated for vesicoureteral reflux only 1 had reflux. Questionnaire followup was obtained for 74% of the patients (mean followup 2.6 years) and 32% felt normal within 3 days. Postoperative symptoms included flank pain (13%), renal colic (12%), pelvic discomfort (30%) and Double-J stent related complaints (49%). Of the patients 15% have reported recurrent stones. Ureteroscopy is effective and well tolerated, and it has minimal long-term complications.

Laparoscopic linear cutting stapler failure

OBJECTIVES To characterize the frequency and nature of problems with linear cutting staplers to help prevent complications in the future. These devices are often used during laparoscopic urologic procedures. METHODS We retrospectively reviewed the experience with laparoscopic linear cutting staplers at two institutions routinely performing urologic laparoscopy and analyzed the difficulties with any staplers. Data from the Food and Drug Administration Center for Devices and Radiological Health were also examined to determine the prevalence and types of reported problems. RESULTS In performing approximately 460 laparoscopic cases, we encountered 5 problems (1%) with endovascular gastrointestinal anastomosis staplers. Fifty-five additional cases in 50 patients were documented in the Food and Drug Administration database. Of the 55 patients, 15 (27%) required open conversion to manage the problem, 8 (15%) received blood transfusions, and 2 (4%) died postoperatively. Twenty-two events occurred during 19 laparoscopic donor nephrectomies (35%) without associated graft dysfunction, damage, or loss. All phases of instrument use were subject to problems; however, abnormal firing of the stapler and improper staple formation were the most common and morbid aspects of device malfunction. CONCLUSIONS Despite the general reliability of linear cutting staplers, difficulties were encountered in every step of use. Most situations were successfully managed by prompt identification and appropriate intracorporeal maneuvers. Nevertheless, significant morbidity may occur, and conversion to an open operation should be considered. Many potential problems can be avoided by surgeon and staff education, and one should be aware of the alternative methods of tissue ligation currently available.

THE USE OF FIBRIN SEALANT IN UROLOGY

PURPOSE Fibrin sealant has been increasingly applied in various surgical fields, including urological surgery, in the last 2 decades. We determined the safety and efficacy of fibrin sealant in urological surgery and identified areas that need further clinical investigation. MATERIALS AND METHODS A MEDLINE search of all available literature regarding the use of fibrin sealant was performed. All articles, including experimental animal studies, prospective and retrospective studies, case series and case reports of fibrin sealant for hemostasis and/or other urological applications, were identified and reviewed. RESULTS Prospective randomized studies in the field of thoracic and trauma surgery show the efficacy and safety of fibrin sealant for hemostasis. Based on these data fibrin sealant has been used successfully for hemostasis during partial nephrectomy and traumatic renal reconstruction. A number of experimental animal studies, case series and case reports show the efficacy of fibrin sealant for ureteral anastomosis, microsurgical vasal anastomosis, fistula repair, circumcision and orchiopexy as well as it use as an adjunct in other areas of reconstruction. CONCLUSIONS Fibrin sealant is an effective and safe topical agent for controlling surface bleeding during elective and trauma related urological procedures. Using fibrin sealant as an adhesive for reconstruction requires further prospective studies. The introduction of laparoscopic procedures in urology may expand the indications for fibrin sealant as an alternative method of tissue reapproximation. Limiting the routine use of fibrin sealant to procedures with demonstrable benefits is desirable and would lead to a cost saving approach.

Urinary stone disease

Urinary stone disease , Urinary stone disease , کتابخانه دیجیتالی دانشگاه علوم پزشکی و خدمات درمانی شهید بهشتی