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Biomedical subjects

M L Stoller

Publications and source records attributed to M L Stoller.

At least 73 records · Page 4Linked to original sources
PubMed1995

[The small urinary calculus: natural course and current treatment concepts].

Depending on size, duration of symptoms and their location in the collecting system urinary calculi may pass spontaneously in 16 to 93% of cases. The rate of infection and increase in size of stones in the renal pelvis or calix reaches 70% within months to years. Ureteral stones, however may lead to complications during a period of days to weeks. New minimally invasive treatment modalities have liberalized the indications for early intervention in cases of small stones.

Endoscopy↗
PubMed1995

The effect of newer generation lithotripsy upon renal function assessed by nuclear scintigraphy.

PURPOSE: We studied the effect of second generation lithotripsy on renal function. MATERIALS AND METHODS: We evaluated 42 patients with unilateral renal calculi by nuclear renography, serum creatinine levels, renal ultrasonography and plain radiographs. RESULTS: There was no significant change in glomerular filtration rate at 1 or 3 months. Split function of the treated kidneys was lower at 1 month (mean 47.2%, p = 0.01) and 3 months (47.3%, p = 0.01) than before treatment (49.1%). A greater than 5% decrease in split function of the treated kidney occurred at 1 month in 6 patients (16.2%) and at 3 months in 3. Of the patients 23 (62.2%) were stone-free and 11 had residual fragments less than 4 mm., with a 19% retreatment rate for an overall success rate of 91.9%. CONCLUSIONS: Newer generation lithotriptors may limit renal damage while permitting satisfactory treatment of renal calculi.

Adult↗
PubMed1995

Entrapped Malecot nephrostomy tube: etiology and management.

Nephrostomy tubes occasionally are resistant to extraction. During the last 7 years 3 such patients with entrapped Malecot nephrostomy tubes have been treated successfully at our university. The entrapped nephrostomy tubes were removed by endoscopically incising an anchoring tissue bridge that had grown over a flange. A small endoscope was easily advanced through the lumen of the entrapped catheter to allow for adequate visualization and electrocautery of the anchoring tissue bridge. With this method an entrapped Malecot nephrostomy tube may be removed intact without significant injury to the renal parenchyma. Malecot nephrostomy tubes should be used with caution for long-term drainage of small intrarenal pelves.

Child↗
PubMed1995

Newborn penile glans amputation during circumcision and successful reattachment.

Circumcision, the most common operation in male patients in the United States, is performed by a variety of health care professionals. Although not technically difficult, it results in a large number of reported and unreported complications annually. We report the successful reattachment of a distal penile glans, which was amputated when the Sheldon clamp was used for newborn circumcision. The literature is reviewed, and prevention and treatment of this type of circumcision injury are described.

Amputation, Traumatic↗
PubMed1995

Endocervicosis of the bladder.

We report a case of endocervicosis of the bladder. The tumor was successfully resected transurethrally. Histopathology of this rare condition is discussed and the literature is reviewed. The natural course of this entity is poorly documented and close followup is mandatory. When endocervicosis is differentiated confidently from adenocarcinoma, local treatment may be satisfactory.

Adenocarcinoma↗
PubMed1994

Urologist directed percutaneous nephrostomy tube placement.

A retrospective analysis of 100 consecutive ultrasonically guided percutaneous nephrostomy tubes placed under the guidance of urologists was done. Complications related to tube insertion included sepsis in 3% of the cases, renal pelvic perforations in 2% and hemorrhage in 1%. There were no deaths and no need for open surgical intervention to manage these complications. An additional 21% of the tubes malfunctioned more than 24 hours after insertion, including dislodgement in 11%, occlusion in 6%, hemorrhage in 1%, peritubular leakage in 1%, puncture site infection in 1% and severe incrustation in 1%. These delayed complications were independent of tube type. Nephrostomy tubes may be placed safely by urologists. Urologists usually direct the need for percutaneous nephrostomy tube placement and use these ports for endourological manipulations and, therefore, they should have a greater role in catheter insertion.

Adult↗
PubMed1994

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.

Adolescent↗
PubMed1994

Inhibition of calculi fragment growth by metal-bisphosphonate complexes demonstrated with a new assay measuring the surface activity of urolithiasis inhibitors.

To evaluate compounds for the long-term inhibition of urinary calculi growth, we applied a newly developed in vitro assay to various metal-ligand complexes. The new experimental model--the preadsorbed calculi growth assay--was based upon the initiation of crystal growth in a metastable solution of calcium and oxalate with uniform granules derived from human renal calculi. Potential inhibitors were first absorbed onto the surface of the calculi granules, following which the loss of calcium from the seeded metastable solution was monitored as the indicator of calcium oxalate deposition. This assay allowed participation in the reaction by any matrix components present in the human calculi granules and limited the effect of the inhibitors to the calculi surface. Some complexes of metal ions with bisphosphonates had strong inhibitory effects, as opposed to citrate complexes which had minimal effect in this assay. Tin was the most potent metal ion, and pamidronate was the most potent bisphosphonate; together they slowed the growth of calculi granules to 9% of control. The inhibition by Tin-bisphosphonate complexes persisted despite a week of continual rinsing with a solution of sodium chloride and calcium. If the metal-bisphosphonate complexes are active in vivo as well, they might be considered for prophylaxis of calcium oxalate calculi or the prevention of regrowth of residual fragments following lithotripsy.

Calcium↗
PubMed1994

Improved renal function following aggressive treatment of urolithiasis and concurrent mild to moderate renal insufficiency.

To our knowledge the prevalence of urinary stone disease and concurrent mild to moderate renal insufficiency has never been reported. A review of our last 2,000 urinary stone patients identified 33 (1.65%) with serum creatinine levels of 2.0 mg./dl. or greater at presentation. Chemical composition, location and complexity of the calculi, types of procedures required to render the patient stone-free and the effect of surgical intervention (independent of relief of obstruction) on renal function were evaluated. Mean serum creatinine level before surgical intervention and after placement of a ureteral stent or percutaneous nephrostomy tube in patients with evidence of obstruction was 3.2 mg./dl. (range 2.0 to 7.5). Complete or partial staghorn calculi were found in 21 of the 33 patients (64%), including 8 with bilateral staghorn calculi. Seven patients required 1 procedure, 1 required urinary alkalization alone and the other 25 required an average of 3.5 procedures each. Stone analysis revealed struvite, mixed calcium and uric acid to be the most common types. Followup creatinine values (the latest available within 1 year) and corresponding creatinine clearances showed remarkable improvement. The mean decrease in serum creatinine level was 1.2 mg./dl. (p < 0.001). There was no statistically significant difference in the rate of decrease between patients with pretreatment serum creatinine levels of 2.0 to 2.9 mg./dl. and those with initial values of 3.0 or more. Renal calculi and concurrent mild to moderate renal insufficiency warrant aggressive treatment. Patients demonstrate significant improvement in renal function independent of relief of obstruction.

Adult↗
PubMed1994

Fibroepithelial ureteral polyps and urolithiasis.

Fibroepithelial polyps are the most common benign tumor of the ureter. Most of the literature regarding their cause ascribes it to chronic infection. These publications, however, show that the majority of such cases never were associated with a documented urinary tract infection. Fibroepithelial polyps appear with equal frequency in male and female subjects and are found in all age groups including children, in contrast to what would have been expected with an infectious cause. Four histologically confirmed cases of fibroepithelial polyps were associated with chronic inflammation of the upper urinary tract related to the presence of calculi and/or Double J ureteral stents. All patients were managed successfully by endoscopic means, preserving renal function. Fibroepithelial ureteral polyps may be associated with urolithiasis, which serves as a source of chronic inflammation. A review of the literature is presented and supports these observations.

Adult↗
PubMed1994

Pediatric ureteropelvic junction obstruction treated with retrograde endopyelotomy.

OBJECTIVES: To determine the feasibility of retrograde endopyelotomy in the management of pediatric ureteropelvic junction (UPJ) obstruction. METHODS: We treated 2 boys aged 4 and 6 years with the Acucise endopyelotomy device for symptomatic ureteropelvic junction obstruction. The Acucise device was placed over a Lunderquist guide wire with fluoroscopic guidance only and routine Double J catheters were left in situ for 6 weeks after the procedure. The morbidity of the treatment and the short-term outcome were assessed. RESULTS: There were no acute complications and short-term follow-up results were satisfactory as determined by intravenous urography and diuretic renography. CONCLUSIONS: Ureteropelvic junction obstruction in children may be treated by retrograde endopyelotomy with the Acucise device. The principal potential advantage of this procedure is reduced morbidity. Our findings suggest that further evaluation is warranted.

Catheterization↗
PubMed1994

Hypothermia associated with percutaneous nephrolithotomy.

OBJECTIVES: To characterize the perioperative fall in core body temperature associated with percutaneous nephrolithotomy, and to identify patients at greater risk of hypothermia. METHODS: A retrospective review was undertaken of core body temperatures in 77 patients who underwent 95 percutaneous nephrolithotomy (PNL) procedures using room temperature irrigants over a 3 year period. Intraoperative temperature measurements were obtained via an esophageal thermistor probe. RESULTS: Mean core body temperature fell from 36.7 degrees C preoperatively to 35.8 degrees C after retrograde manipulations and subsequent patient positioning before commencing the renal puncture. The mean core temperature fell an additional mean 1.0 degrees C during the percutaneous nephrolithotomy. This additional temperature drop was proportional to the length of the procedure. Female patients had a significantly greater decline in intraoperative core body temperature than male patients (p < 0.01). Obese patients preserved their preoperative temperature more efficiently. Blood loss and advanced age had no impact on the occurrence of hypothermia. Mean preoperative temperature was regained on average within 3 hours postoperatively. CONCLUSIONS: Hypothermia occurs in the majority of patients undergoing PNL. Nearly an equivalent fall in temperature is seen during presurgical preparation, induction of anesthesia, and patient positioning as is seen during the surgical procedure itself. Efforts to preserve core body temperature both before and during the percutaneous procedure may reduce the degree of hypothermia and its potential complications.

Body Temperature↗
PubMed1994

Percutaneous nephrolithotomy in the elderly.

OBJECTIVES: To evaluate the success and morbidity of percutaneous nephrolithotomy (PNL) performed in patients aged 65 years and older. METHODS: A retrospective review of 42 PNLs performed on 33 patients aged 65 years and older was compared with a cohort of 160 PNLs performed on younger patients over the same time period. RESULTS: The presence of complete staghorn calculi (17 of 36 renal units [47%] versus 88 of 160 renal units [55%], p = 0.46) and average stone size (3.8 cm versus 4.3 cm, p = 0.2) were similar for the 2 groups. Eighty-two percent of patients (27 of 33) were stone-free or left with fragments < 5 mm at 3 months after surgery. Elderly patients had a higher transfusion rate after PNL despite similar preoperative hemoglobin levels (11 of 42 PNLs [26%] versus 22 of 160 PNLs [14%], p < 0.01). Serious complications were infrequent and there were no deaths. CONCLUSIONS: Percutaneous nephrolithotomy is a safe and effective therapy for elderly patients with complex stone disease; however, awareness of an apparent increased requirement for blood transfusion is warranted.

Age Factors↗
PubMed1994

Urolithoscintigraphy: preliminary report of a new imaging modality for urolithiasis.

We investigated the use of bisphosphonates, analogs of pyrophosphate that bind to mineralized tissue, to image renal calculi in vivo. Twenty stone-bearing kidneys in 15 patients without urinary obstruction were studied. 99mTechnetium-methylene diphosphonate was injected intravenously followed by 20 mg of furosemide 4 hours later, and images were obtained by gamma counter for 30 minutes. Areas of increased uptake corresponded with the sites of calculi, and even small or radiolucent calculi were easily seen. Counts in the region of each kidney, the L4 vertebral body, and a background area were combined to calculate a scintigram index (SI) for each kidney. The mean SI of the stone-bearing kidneys was 4.8 +/- 3.5 v 1.3 +/- 0.4 for the normal kidneys. There was correlation of the SI with stone composition and size but not with radiographic density. After correction for size, the SI of stone-bearing kidneys remained significantly higher than the SI of normal kidneys, but the differences between calculi of different compositions were diminished. Nonetheless, high SI values were associated with soft types of calculi and low values with hard types. Future investigations will reveal if this association is constant and if there is any relation between bisphosphonate uptake and response to lithotripsy. The sensitivity of urolithoscintigraphy to image small or radiolucent calculi may make it an effective technique for the assessment of residual fragments after lithotripsy.

Diphosphonates↗
PubMed1994

Endoscopic ureteroneocystostomy for post-transplantation ureterovesical junction stenosis.

We report a new technique for the management of ureterovesical junction stenosis in a renal transplant recipient. Endoscopic retrograde resection of a bladder window permitted direct retroperitoneal vision and longitudinal incision of the distal ureter. Ureteral and bladder mucosa were in close proximity and were stabilized with a double-J catheter. This alternative transmural transvesical ureteroneocystostomy had minimal morbidity and may be an alternative to traditional open surgical repair of these lesions.

Adult↗
PubMed1994

Urologic applications at a community zoo.

The genitourinary system is a common source of disease in many animal species as well as humans, and the practice of comparative endourology is possible because of advances in the past decade in minimally invasive human surgery. Zoo veterinarians may have limited formal urologic training, and increasingly limited public funding resources now leave most community zoos without specialized endourologic equipment or expertise. Urologists may offer or be called on to assist in the diagnosis and management of often rare and valuable species, providing services and expertise previously limited to humans. Such cases may provide intellectual and technical challenges beyond those seen in clinical practice, while applying the same basic universal urologic principles. We describe a cooperative approach to the management of animal urologic disorders based on a 5-year experience as consultants to the San Francisco Zoo and encourage an interdisciplinary approach between urologists and their local zoos where this may be useful in the preservation and maintenance of these valuable and important public resources.

Animal Diseases↗