Search PubMed⌕ Search

Biomedical subjects

David A Diamond

Publications and source records attributed to David A Diamond.

25 records · Page 2Linked to original sources
PubMed2004

Anterior urethral valves and diverticula in children: a result of ruptured Cowper's duct cyst?

OBJECTIVE: To review a series of children with anterior urethral valves and diverticula, to elucidate the pathophysiology and optimal management of this entity. PATIENTS AND METHODS: Nine cases (all boys; 1963 to 2003) were reviewed retrospectively. RESULTS: Seven of nine boys had bulbar diverticula. Continuity between Cowper's duct and the diverticulum was noted endoscopically in two and confirmed radiographically in one. Initially, open surgery was curative but more recently endoscopic management has been the procedure of choice. CONCLUSION: This series indicates that the distal lip of a ruptured syringocele may function as a flap-valve, leading to anterior urethral obstruction. Advances in imaging and endoscopic instruments have altered the mode of presentation and management of this entity.

Bulbourethral Glands↗
PubMed2003

Mechanisms of failure of endoscopic treatment of vesicoureteral reflux based on endoscopic anatomy.

PURPOSE: We examined the mechanisms responsible for technical failure of the endoscopic technique for correcting vesicoureteral reflux based on endoscopic anatomy. MATERIALS AND METHODS: The study included 25 patients, 2 to 15 years old (mean age 8) who received 57 ureteral injections on 1 or more occasions which failed to correct reflux. Each endoscopic procedure for every patient was videotaped and endoscopic photographs were taken to document pretreatment and posttreatment anatomy. Based on the comparative endoscopic anatomical findings, failures were categorized as secondary to volume loss, mound displacement, mound extrusion or indeterminate etiology. RESULTS: Of the 57 ureters the cause of failure was believed to be due to mound displacement in 35%, volume loss in 23%, displacement and volume loss in 29%, mound extrusion in 2% and indeterminate in 11%. The direction of mound displacement was toward the bladder neck (medial, distal) in 76% of those cases. CONCLUSIONS: Endoscopic anatomical findings can account for failure of the injection technique to correct reflux in the majority of failed cases (90%). Mound displacement and volume loss account comparably for treatment failure. One incidence of mound extrusion, previously hypothesized as a mechanism for treatment failure, was documented in our study.

Adolescent↗
PubMed2002

Rate and predictors of spontaneous resolution of prenatally diagnosed primary nonrefluxing megaureter.

PURPOSE: We assessed clinical and ultrasound predictors of the spontaneous resolution of prenatally diagnosed, primary nonrefluxing megaureter. MATERIALS AND METHODS: Primary nonrefluxing megaureter was prenatally diagnosed in 54 neonates from 1993 to 1998, including 15 in whom it was bilateral (69 megaureters). Median followup period from birth to the last radiology examination was 25.8 months (range 2.3 to 72). RESULTS: Of the patients 10 underwent surgical repair for severe hydroureteronephrosis, including decreasing renal function on diuretic renography in 1, and an episode of bilateral obstruction and acute renal failure in 1. Hydroureteronephrosis resolved in 39 cases (72%) and persisted in 5 at 30 to 72 months of followup. Laterality, gender and retrovesical ureteral diameter had no significant effect on the resolution rate (p >0.05). Mean initial ureteral diameter in patients with resolution was less than in those without resolution and in those who underwent surgery (0.8 versus 1.15 and 1.32 cm., respectively). Presenting hydronephrosis grade was a significant predictor of the resolution rate (p = 0.03). Grades 1 to 3 hydronephrosis resolved at a median age of 12.9, 23.9 and 34.6 months, respectively (range 4.1 to 66). In patients in whom grades 4 and 5 hydronephrosis resolved the median age at resolution was 48.5 months. CONCLUSIONS: Most cases of prenatally diagnosed, primary nonrefluxing megaureter resolve spontaneously. Grades 1 to 3 hydronephrosis tend to resolve between ages 12 and 36 months. For these grades followup intervals may be progressively elongated after a pattern of improving hydronephrosis has been established. In children with grade 4 or 5 hydronephrosis, or a retrovesical ureteral diameter of greater than 1 cm. the condition may resolve slowly and require surgery.

Child↗
PubMed2002

Testicular volume: comparison of orchidometer and US measurements in dogs.

PURPOSE: To compare the accuracy and precision of orchidometer and ultrasonographic (US) measurements of testicular volume in a canine model. MATERIALS AND METHODS: Volume measurements of 18 canine testes were obtained by using Prader and Rochester orchidometers. Testes were scanned with two linear-array US transducers with imaging frequencies of 6-13 MHz and 5-10 MHz. For each transducer, testicular volumes were calculated by using three formulas: length (L) x width (W) x height (H) x 0.52, L x W(2) x 0.52, and L x W x H x 0.71. Testes were weighed following bilateral orchiectomies. True testicular volume was determined by using the formula volume = weight/density. Paired t tests were used to assess whether mean measurement biases differed significantly from zero. The relationship between true and measured volume was evaluated with a linear regression model. RESULTS: US volume measurements demonstrated lower variability and better linear fit compared with orchidometry (R(2) = 0.75-0.90 vs R(2) = 0.14-0.38). The formula L x W x H x 0.71 had the smallest mean bias relative to true volume with use of either transducer over the entire volume range. CONCLUSION: US methods of testicular volume measurement are more accurate and precise than orchidometry. The formula L x W x H x 0.71 provides a superior estimate of testicular volume and should be used in clinical practice.

Animals↗
PubMedDate not supplied

Vesicoureteral reflux: diagnosis and management.

Vesicoureteral reflux is the retrograde passage of urine from the bladder into the ureter and kidneys during voiding. This commonly-treated entity is frequently managed by different disciplines that include Urology, Nephrology and Pediatrics. The pathophysiology of vesicoureteral reflux seems to be related to the valve mechanism of the ureterovesical junction. Abnormal location of the ureteral orifice is implicated in the short ureteral tunnel which in turn compromised the flap-valve mechanism. The grading of reflux is important since management depends on the severity according to a five grade system. At present, medical management using antibiotic prophylaxis has become well established for managing patients with low-grade reflux (grades I-III). Moderate reflux (grade III-IV) could be managed by surgery in case of breakthrough infections. Recommendations regarding the diagnosis and medical management remain complex and are continuously evolving. More frequently than not, treating pediatricians and urologists would have to make decisions by individualizing each patient and considering the likelihood that patient's reflux will resolve.

Anti-Infective Agents, Urinary↗