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Biomedical subjects

Andrew J Kirsch

Publications and source records attributed to Andrew J Kirsch.

10 recordsLinked to original sources
PubMed2003

MR imaging of kidneys: functional evaluation using F-15 perfusion imaging.

BACKGROUND: Children with hydronephrosis are typically investigated by a combination of diuretic renal scintigraphy, ultrasound, and voiding cystourethrography. Unfortunately, there is no gold standard to assess obstruction. PURPOSE: The purpose of our study was to evaluate the utility of dynamic contrast enhanced MR urography in the investigation of children with hydronephrosis to define urinary tract anatomy, to calculate differential renal function and to assess urinary tract obstruction. MATERIALS AND METHODS: Dynamic contrast-enhanced MR imaging was performed in 40 children with unilateral hydronephrosis. There were 14 girls and 26 boys with an age range of 1 month to 14 years (mean 1.4 years). The information from traditional imaging modalities was compared to the information obtained from the single MR study. RESULTS: The anatomic imaging with MR urography was superior to other modalities. The split renal function was estimated with MR urography by calculating the volume of enhancing renal parenchyma and was comparable to renal scintigraphy ( r=0.98). By using surgery versus non-surgery as the decision point, with MR urography the sensitivity was 100%, specificity 71%, positive predictive value 86%, negative predictive value 100%, and diagnostic efficiency 90%. For renal scintigraphy the sensitivity was 96%, the specificity 56%, positive predictive value 76%, negative predictive value 90%, and diagnostic efficiency 79%. CONCLUSIONS: Dynamic contrast-enhanced MR urography provides superior anatomic and functional information when compared with ultrasound and diuretic renal scintigraphy. The information is gathered in a single study that does not use ionizing radiation. It is likely that MR urography will replace renal scintigraphy in the evaluation of hydronephrosis in children.

Adolescent↗
PubMed2003

Laser tissue soldering: applications in the genitourinary system.

Within the past 25 years, lasers have transitioned from merely destructive or ablative tools to those with reconstructive uses. It has been shown that the application of laser thermal energy to tissue will result in welding of the approximated areas. Furthermore, the addition of protein solder and chromophores (tissue soldering) has increased wound tensile strength while decreasing peripheral tissue damage. Laboratory studies have demonstrated application of laser tissue soldering to virtually all components of the genitourinary system. Increasing human experience in recent years has reinforced the success of this technique.

Animals↗
PubMed2003

Bimanual digital rectal examination for the evaluation of the nonpalpable testis.

PURPOSE: In the evaluation and treatment of the nonpalpable testis open surgical exploration and laparoscopy are methods used to differentiate abdominal, infrainguinal (below the internal ring) and atrophic or absent testes. We sought to evaluate the use of bimanual digital rectal examination as an additional tool to localize the nonpalpable testis. MATERIALS AND METHODS: Forty-one consecutive patients with 45 nonpalpable testes were evaluated in a prospective fashion. Bimanual digital rectal examination was performed with the patients under general anesthesia just before diagnostic laparoscopy or open inguinal exploration. Palpability, location, length and contralateral testicular length were recorded. RESULTS: Twenty-five gonads or spermatic cords (56%) were palpable using the bimanual technique. All positive examinations were confirmed laparoscopically or by open exploration, and the majority of gonads were intra-abdominal (17 of 25, 68%). Seventeen normal appearing gonads underwent orchiopexy and 8 were removed secondary to atrophy, dysgenesis or poor position. Twenty testes (44%) were not palpated using this method. Of these gonads 10 normal appearing testes were found at exploration and underwent orchiopexy. Of the 10 remaining gonads 6 atrophic testes were removed, and 4 hemosiderin laden remnants were thought to represent "vanished testes." Overall, 26 gonads or remnants were intra-abdominal, 10 were "peeping" or canalicular and 9 were infrainguinal. The overall specificity was 100%, with a sensitivity of 60%. The positive predictive value was 100%. CONCLUSIONS: Bimanual digital rectal examination is a valuable tool in the evaluation of the nonpalpable testis, and identified the presence and position of the testis in the majority of our cases. Although sensitivity is low, when the testis is palpated by this method, diagnostic laparoscopy to localize the testis may be avoided.

Algorithms↗
PubMed2003

Minimally invasive treatment of vesicoureteral reflux with endoscopic injection of dextranomer/hyaluronic acid copolymer: the Children's Hospitals of Atlanta experience.

PURPOSE: Emerging data demonstrate that injection of dextranomer/hyaluronic acid (Dx/HA) copolymer (Deflux, Q-Med Scandinavia, Uppsala, Sweden) is a safe and effective treatment for most patients with vesicoureteral reflux (VUR). We sought to determine the efficacy and factors predictive of outcome in patients treated with Dx/HA. MATERIALS AND METHODS: A total of 180 children 7 months to 15 years old (mean age 4.6 years) underwent subureteral injection of Dx/HA for VUR between October 2001 and February 2003. Dx/HA was injected submucosally within or beneath the intramural ureter. The average volume of injected material was measured for each ureter. At 2 weeks and 3 months postoperatively bladder ultrasounds were performed to measure the volume of Dx/HA (mm3) in the trigone using the volume of an ellipsoid (V = 4/3pir(1)r(2)r(3)). Renal sonography was performed to determine whether hydronephrosis was present. At 3 months fluoroscopic voiding cystourethrograms were used to evaluate for the presence of VUR. RESULTS: A total of 292 ureters in 180 children were treated (112 bilateral cases). There were 141 girls and 39 boys. Mean maximum grade per patient was 2.6 (out of 5). Average injected volume per ureter was 0.83 +/- 0.03 ml (830 +/- 30 mm3). At 2 weeks the average measured volume was 663 +/- 70 mm3 (18% decrease from original volume), which decreased an additional 1% by 3 months to 656 +/- 103 mm3. There were no cases of hydronephrosis at up to 12 months postoperatively.There were 134 patients with at least 3 months of followup. After 1 treatment 72% (96) were cured (grade 0), while 55% of the failures (21 of 38) were improved. New contralateral VUR was seen in 6 patients (4.5%) who had neither a history of VUR nor an abnormal appearing ureteral orifice at cystoscopy. A lower success rate (60%) was seen in the first 20 patients compared with the last 20 patients (80%). The cure rate per grade was 90% for grade I, 82% for grade II, 73% for grade III and 65% for grade IV reflux. Local migration of material caudal to the ureteral orifice was seen in 61% of patients (11 of 18) at the time of reinjection of Dx/HA after initial treatment failure. There was no statistically significant difference in age, grade, volume injected, bilaterality or gender when successes were compared with failures. CONCLUSIONS: The majority of patients (72%) undergoing minimally invasive treatment of VUR with Dx/HA are cured after 1 treatment. Contralateral treatment of nonrefluxing ureters should be considered in view of the increased incidence of new reflux (4.5%) and absence of morbidity with Dx/HA injection. There is a definite learning curve with injection therapy. The location of injected material and experience with the technique appear to correlate with the outcome of the procedure.

Child↗
PubMed2003

Direct vision internal urethrotomy for the treatment of pediatric urethral strictures: analysis of 50 patients.

PURPOSE: In an attempt to evaluate our experience with the treatment of pediatric urethral stricture disease we performed a retrospective review of patients undergoing direct vision internal urethrotomy (DVIU). MATERIALS AND METHODS: The computerized surgical logs at 2 pediatric hospitals were reviewed to identify patients who underwent DVIU between 1992 and 2001. Hospital and clinical charts were then reviewed. Many variables were analyzed, including patient age, etiology of stricture, technique and clinical outcomes. Minimum followup to be included in clinical outcome analysis was 12 months. RESULTS: A total of 50 patients were identified (mean age 7.7 years, range 6 months to 17 years). The most common etiology for stricture formation was previous hypospadias repair (20 patients [40%]). Forty patients met the 12-month minimum followup requirement for clinical outcome analysis. Of these patients 20 (50%) had no symptoms to suggest recurrent stricture at a median of 2.0 years (mean 2.7 years, range 12 months to 7 years). Seventeen patients (42.5%) had symptoms of recurrent stricture at a median of 8 months (mean 13 months, range 2 months to 5 years). Technical factors did not influence the ultimate success or failure of the procedure. CONCLUSIONS: DVIU provides a therapeutic option that successfully treats approximately half of the patients with a reasonably low complication rate. Complications following DVIU should not preclude its use as a therapeutic modality for the treatment urethral strictures in children. If the child fails the initial DVIU, repeat attempts at endoscopic correction of urethral stricture should be abandoned in favor of definitive urethroplasty.

Adolescent↗
PubMed2002

Advances in bladder augmentation.

Over the past 20 years, rapid advances have been made in bladder augmentation due to the introduction of clean intermittent catheterization, the use of intestinal segments interposed into the urinary tract, and the development of tissue expansion. The particular augmentation method selected from the multiple methods currently available is an individualized process that takes into account both patient factors and potential complications. Exciting new techniques, such as tissue engineering, may change the face of lower urinary tract reconstruction.

Humans↗
PubMed2002

Metabolic risk factors for stone formation in patients with cystic fibrosis.

PURPOSE: Cystic fibrosis is characterized by chronic pulmonary disease, insufficient pancreatic and digestive function, and abnormal sweat concentrations. Patients with cystic fibrosis also have an increased incidence of nephrolithiasis. We compared the results of metabolic evaluation in patients with cystic fibrosis with and without nephrolithiasis. MATERIALS AND METHODS: A total of 496 patients were evaluated at our center, including 98 with a mean age of 25 years who had cystic fibrosis and complete metabolic evaluation available between 1996 and 2000. Of these patients 13 (13%) had a history of nephrolithiasis. The records were reviewed for clinical characteristics and all patients underwent metabolic evaluation, including serum electrolyte measurement and 24-hour urine collection. Statistical analysis was done to compare the stone versus nonstone groups. RESULTS: The incidence of nephrolithiasis in our study was 3%. We identified 13 patients 16 to 41 years old (mean age 27) with nephrolithiasis, of whom 62% had had multiple episodes. Flank pain was the presenting symptom in 9 of the 13 cases (69%). Renal ultrasound and computerized tomography were the most common imaging modalities. In 9 cases stones were passed without intervention, extracorporeal shock wave lithotripsy was required in 2 and ureteroscopy with stone extraction was done in 2. Calcium oxalate was the dominant stone composition in the 9 patients in whom stone analysis was performed. Metabolic evaluation of the stone versus no stone groups showed elevated urinary oxalate (45.5 versus 42.5 mg./24 hours), relative calcium oxalate supersaturation (5.3 versus 7.2) and decreased urinary citrate in the 2 groups. There was a statistical difference in citrate excretion with lower levels in stone formers (102 versus 218 mg./24 hours, p = 0.0007). CONCLUSIONS: Patients with cystic fibrosis have an increased incidence of nephrolithiasis and are at high risk for recurrence. Metabolic evaluation is indicated in all patients with cystic fibrosis and urolithiasis since most have hyperoxaluria, urinary calcium oxalate supersaturation and decreased urinary citrate. Correcting detected stone risk factors in these cases may decrease stone recurrence.

Adolescent↗
PubMed2002

Antenatal intervention: jeopardizing life or limb?

The association of limb loss with antenatal urologic intervention has recently been questioned. At present, no such cases have been reported. We present a case of antenatal vesicoamniotic shunting for posterior urethral valves in which the shunt entered the right lower extremity and coursed subcutaneously over the femoral triangle and inguinal canal and into the bladder. Although the limb was intact, we present images and a discussion of the potential for extremity injury with antenatal urologic intervention.

Adult↗
PubMed2002

Blunt traumatic hematuria in children. Is a simplified algorithm justified?

PURPOSE: We determined whether radiographic evaluation is indicated in all children with traumatic hematuria. MATERIALS AND METHODS: We retrospectively reviewed the records of 110 children from 1992 to 1999 diagnosed with blunt trauma and hematuria. It is routine practice at our emergency department to perform radiographic evaluation in all children with hematuria regardless of the degree. Each chart was evaluated for the mechanism of injury, degree of hematuria, hypotension, imaging studies, renal injury, renal anomalies, associated injuries and outcome. RESULTS: A total of 110 patients 1 to 18 years old (mean age 9) were identified. The most common mechanism of injury was motor vehicle accident in 37 children (34%), followed by a fall in 32 (29%). Grades I to V renal injury was present in 5, 6, 6, 6 and 1 cases, respectively (22%), while 1 (0.9%) involved ureteropelvic junction avulsion. No child had renal pedicle injury. In 9 patients renal anomalies were detected incidentally. Of the 110 patients 101 underwent radiographic evaluation, including computerized tomography in 97 (88%). The 24 patients (22%) with significant renal injury and all with incidentally diagnosed renal anomalies had 50 or greater red blood cells per high power field on urinalysis, while 1 with ureteropelvic junction avulsion presented without hematuria. Hypotension was present in only 3 patients (2.7%), who also had associated injuries, including 2 who presented with renal injury. All 3 with associated injuries. Associated injuries were identified in 11 of 25 patients (44%). The 9 patients (8%) who did not undergo radiographic imaging had negative results on repeat urinalysis with an excellent outcome. CONCLUSIONS: We recommend that radiological evaluation consisting of abdominal and pelvic computerized tomography should be performed only in patients with 50 or greater red blood cells on urinalysis, hypotension at presentation to the emergency room or based on the severity of mechanism of injury, for example high speed motor vehicle accident deceleration injuries. The patient who presented with ureteropelvic junction avulsion without hematuria would have undergone imaging considering the mechanism of injury and number of associated injuries.

Accidental Falls↗