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Biomedical subjects

D A Canning

Publications and source records attributed to D A Canning.

At least 55 records · Page 3Linked to original sources
PubMed1997

Surgical repair of urethral circumcision injuries.

PURPOSE: The 2 types of urethral injury that can occur during circumcision are urethrocutaneous fistula and urethral distortion secondary to partial glans amputation. We report the surgical repair of these rare injuries. MATERIALS AND METHODS: In 8 patients urethrocutaneous fistulas located on the distal penile shaft or at the coronal margin were managed by splitting the glans and using a Mathieu style skin flap in 4 or vascularized penile skin flap in 4 to bridge the urethral defect. Three patients underwent repair of a hypospadiac deviated urethra secondary to partial glans amputation by 1 cm. of urethral mobilization and repositioning the meatus into a terminal position within the remaining glans tissue. RESULTS: The 8 patients with urethrocutaneous fistulas voided via a terminal meatus without fistula recurrence at a mean followup of 3.2 years (range 1 to 6). The 3 patients with partial glans amputation and urethral deviation repaired by short urethral advancement had functionally acceptable results, defined as a normal urinary stream, although 1 required meatal dilation postoperatively. CONCLUSIONS: The 2 types of urethral injuries that can occur during circumcision are a subcoronal urethrocutaneous fistula and scarred abnormal urethra from partial glans amputation. The urethrocutaneous fistula can be successfully repaired by splitting the glans and forming a neourethra from a vascularized pedicle flap of penile skin. The abnormal urethra after partial glans amputation is more difficult to repair but repositioning the urethra in a more cosmetic location has restored function.

Child, Preschool↗
PubMed1997

Skin flap closure by dermal laser soldering: a wound healing model for sutureless hypospadias repair.

OBJECTIVES: Laser tissue soldering (LTS) with the diode laser and human albumin-hyaluronate-indocyanine green solder is a safe and effective method of providing an immediate leak-free closure during hypospadias repair. In this report, we compare the physiology, histology, and immunohistochemistry of wound healing following LTS and suturing in a rat skin flap model. METHODS: A 4 x 5-cm skin flap was raised and bisected (4 cm) on the dorsum of 48 Sprague-Dawley rats. The central wound was either closed from a dermal approach by suturing or LTS or left open, and studied at 0, 3, 5, 7, 10, 14, and 21 days postoperatively. An intraoperative comparison was made between suturing and LTS with respect to operative time. Postoperatively, flaps were excised for tensiometric analysis, and sections were stained with hematoxylin-eosin to define wound architecture. Resting skin temperature, laser exposed temperature without solder, and maximum temperature with solder (one drop) were measured at the level of the deep dermis, superficial striated muscle layer, and within the solder. Mean peak temperatures were recorded during a 1-minute laser activation time. RESULTS: Mean continuous suturing time (4.9 +/- 1.1 minutes) was significantly (P < 0.001) faster than either LTS (7.7 +/- 0.77 minutes) or discontinuous suturing (8.2 +/- 0.62 minutes). Two seromas (sutured) and two instances of partial wound dehiscence (1 sutured, 1 LTS) were noted. Tensile strength was increased significantly (P < 0.001) for up to 5 days in the LTS group, but was equal to suturing at 7 and 10 days. Immediate tensile strength after LTS was equivalent to a 7-day healed wound. At 14 days, wounds initially left open and those closed by LTS were stronger than sutured wounds (P < 0.05). There was no evidence of thermal injury or foreign body reaction in the LTS group. Solder was incorporated within the dermis in all wounds at 21 days. Laser activation of solder resulted in significant increases in temperature at all three tissue levels: 65.0 +/- 5.2 and 69.9 +/- 6.8 degrees C in the deep and superficial skin (no significant difference between the two), and 101 +/- 15.6 degrees C within the solder (P < 0.001 versus superficial and deep skin). CONCLUSIONS: Our results indicate that sutureless dermal LTS of skin flaps provides increased tensile strength for up to 7 days, with relatively greater tensile strength provided within the first 3 days. Our laser technique does not appear to alter the normal wound healing process. Rather, solder-tissue interaction initially, and extracellular matrix infiltration of solder later, provide the basis for improved wound strength. For hypospadias repair using skin flaps, these wound attributes may permit sutureless surgery.

Animals↗
PubMed1997

The operative management of recurrent ureteropelvic junction obstruction.

PURPOSE: Surgical repair of ureteropelvic junction obstruction is successful in 98% of cases. We evaluated children undergoing repeat pyeloplasty and discuss the etiology of recurrent ureteropelvic junction obstruction, surgical approach and outcome. MATERIALS AND METHODS: Between 1982 and 1996, 366 children with ureteropelvic junction obstruction were surgically treated at our institution, including 16 who presented with recurrent ureteropelvic junction obstruction and required surgery. RESULTS: Repeat repair was successful in all 16 patients, including ureterocalicostomy in 3 and dismembered pyeloplasty in the remainder. No nephrectomy was necessary. Anteriorly elongated flank incisions were made in all cases. Dense scar tissue around and obstructing the ureteropelvic junction was noted in the majority of cases. In 7 patients a redundant pelvis resulted in a kink at the ureteropelvic junction. A nephrostomy tube was placed in all cases and an additional transanastomotic stent was used in all but 2. Obstruction was relieved with 1 operation. CONCLUSIONS: A redundant pelvis resulting in a kink at the ureteropelvic junction may contribute to a higher change of urinary leakage and subsequent obstructive scar formation in cases of failed pyeloplasty. Before repeat surgery anatomy should be precisely identified by antegrade and retrograde studies. The surgical approach usually involves identifying the ureter below the area of the previous surgery and then ensuring a tension-free anastomosis. If inadequate ureteral length or an intrarenal pelvis precludes direct anastomosis, ureterocalicostomy is an alternative. A nephrostomy tube and transanastomotic stent are advisable. Nephrectomy is rarely necessary and a good functional result can be anticipated.

Child↗
PubMed1997

Testis sparing surgery for steroid unresponsive testicular tumors of the adrenogenital syndrome.

PURPOSE: Surgical management of steroid unresponsive testicular tumors of the adrenogenital syndrome has been orchiectomy. Magnetic resonance imaging (MRI) of these tumors accurately delineates the extent of disease. Testis sparing surgery is an important consideration, since male individuals with congenital adrenal hyperplasia are potentially fertile. We present our results of surgical management of this tumor based on MRI findings. MATERIALS AND METHODS: Four boys with steroid unresponsive testicular tumors of the adrenogenital syndrome were evaluated with MRI, testicular ultrasound and color flow Doppler examinations preoperatively and postoperatively. Three patients had 21-hydroxylase deficiency and 1 had 3-beta-hydroxysteroid dehydrogenase deficiency. Contralateral testicular abnormalities included a vanished testis, testicular atrophy due to trauma and bilateral tumors in 1 boy each. Bilateral orchiectomy and surgical enucleation were performed in 1 and 3 patients, respectively. Followup ranged from 8 to 18 months. RESULTS: Postoperative MRI of the testis in 2 of 3 patients showed no evidence of recurrent tumor. Postoperative testicular sonography revealed no tumor and vascular flow in 2 of 3 patients. All 3 patients who underwent testis sparing surgery have a viable testis in the scrotum without evidence of recurrent disease. CONCLUSIONS: MRI of the testis in patients with testicular tumors of the adrenogenital syndrome accurately defines the extent of disease. Surgical enucleation of this tumor has been performed successfully without recurrent disease. This surgical approach should be considered for any patient with a steroid unresponsive tumor and contralateral abnormalities. We believe that surgical enucleation is the procedure of choice for all patients with this tumor, since it maximizes future fertility potential.

Adolescent↗
PubMed1997

Laser soldering technique for sutureless urethral surgery.

Investigators have attempted sutureless surgery to decrease operative time, lessen the inflammatory response, maintain luminal continuity, and increase the ease of performing technically difficult surgery. Only recently has laser-tissue welding (LTW) been used for urologic reconstruction in humans. Herein, we present our technique of laser soldering with the half-watt diode laser and wavelength matched albumin-based solder. Our methodology of LTW relies on bonding between the outer surface of the wound edges and the solder. The 808-nm diode wavelength does not penetrate deep tissue, and thus relies on indocyanine green dye to localize photon absorption. Since 1994, we have performed LTW, as an adjunct to suturing (N = 25) and as a primary means of tissue closure (N = 11). Preoperative diagnoses included hypospadias, urethral stricture, urethral diverticulum, and urethral fistulae. Follow-up ranged between 3 months and 3 years to identify complications of wound healing, stricture, and fistula formation. In the 37 patients undergoing urethral surgery, no strictures or diverticula have resulted. None of the patients have had wound infections or poor wound healing. Overall, five patients have developed fistulas between 2 weeks and 6 months postoperatively. The location of the hypospadiac meatus was scrotal or penoscrotal in four of these patients. Two fistulas developed following sutureless urethroplasty (reoperative) after traumatic catheterization for urinary retention (one case for inadvertent catheter removal). In our initial experience, the overall complication rate using laser soldering was 19% compared to 24% in an historical control group. Half of the complications occurred in a reoperative situation. More recently, the overall fistula rate was 14%; however, for primary cases, the current fistula rate is only 6%. LTW is safe and easy to perform. The application of protein solders (+/-chromophores) have permitted far greater tensile strengths to be achieved than laser alone. Temperature-control and chromophore-control have permitted safety and efficacy to be achieved. Solder application site and technique are equally important in the success of the LTW process. A randomized, prospective study comparing LTW to suturing is ongoing.

Adolescent↗
PubMed1996

The long-term outcome in men with exstrophy/epispadias: sexual function and social integration.

PURPOSE: We evaluated the long-term outcome of social integration and sexual function in 29 men with bladder exstrophy and epispadias. MATERIALS AND METHODS: Four men with epispadias and 25 with bladder exstrophy were available for long-term followup. Patients were interviewed by telephone regarding sexual history and social integration. Semen analyses were obtained in 8 cases. RESULTS: Patient assessment of genital appearance was good or fair in 71%. Potency was present in all patients, and erections were straight in 66% and curved in 34% with no curvature so severe as to prevent sexual intercourse. Semen analysis showed a normal sperm count in 63% of the men and no azoospermia. Social integration was satisfactory: 100% of the men attended high school, 55% have a college education and all who are not attending school have full-time jobs. CONCLUSIONS: Our long-term review demonstrates that despite what appears to be a significant sexual handicap, patients with exstrophy/epispadias can have adequate sexual function and overall successful social integration.

Bladder Exstrophy↗
PubMed1996

The long-term outcome of posterior urethral valves treated with primary valve ablation and observation.

PURPOSE: We believe that primary valve ablation with observation is the preferred management for posterior urethral valves. However, debate continues as to the role of high diversion. We examined the long-term outcome of a large series of patients treated with primary valve ablation, and compared it to the outcome of high diversion and vesicostomy. MATERIALS AND METHODS: We reviewed the records of 100 patients treated with primary valve ablation (74%), vesicostomy (13%) or high diversion (9%) before 1985. Median followup was 11.2 years. RESULTS: Overall 13% of our patients had end stage renal disease by age 15 years. Three patients initially treated with valve ablation and 3 initially treated with vesicostomy later underwent high diversion but none benefited from the secondary procedure. Four patients initially treated with valve ablation subsequently underwent vesicostomy but only 1 benefited. Bladder storage capacity was well preserved. Diurnal urinary continence developed in 46% of patients at age 10 years and only 1 remained incontinent after age 20 years. One patient with diversion who awaits transplantation had a small contracted bladder. Recent urodynamic studies in 10 cases of delayed urinary continence have not shown decreased bladder compliance or capacity. Kaplan-Meier analysis of outcomes of the different treatments indicated no statistical difference in patient age at end stage renal disease development. However, comparing the number of surgical procedures in the different treatment groups revealed a significant increase in the amount of surgery in infants with diversion. Our results were equivalent to those of the best published series, many of which strongly advocate high diversion. CONCLUSIONS: By avoiding diversion in most cases bladder function is preserved and the need for bladder augmentation is decreased.

Child↗
PubMed1996

10-year experience with prenatal intervention for hydronephrosis.

PURPOSE: We evaluated clinical outcomes after attempted prenatal intervention in fetuses with hydronephrosis. MATERIALS AND METHODS: We retrospectively reviewed the histories of 10 fetuses considered for prenatal intervention between 1984 and 1993. One female and 8 male fetuses had bilateral hydroureteronephrosis and profound or progressive oligohydramnios, and 1 male fetus had massive progressive unilateral hydronephrosis. RESULTS: Shunt placement was not recommended and it was refused by the parents in 1 case each. Amniotic shunting was attempted in 8 fetuses between 22 and 28 weeks of gestation. Shunts were successfully placed with decreased hydronephrosis and increased amniotic fluid volume in 4 cases, while shunt placement was not technically possible in the remainder. Two shunts that retracted intra-abdominally at birth required laparotomy for retrieval. Postnatally all patients with shunts had compromised renal function. Of the 4 patients in whom attempts were unsuccessful 3 had mildly diminished renal function and 1 died of nonrenal causes (intraabdominal sepsis) on day 16 of life. No patient with a functioning shunt had postnatal pulmonary problems, whereas 3 without successful intervention had mild respiratory compromise. CONCLUSIONS: No definite advantage was noted in the small number of fetuses that underwent successful shunting. Successful shunt placement did not prevent renal insufficiency. The relief of oligohydraminos may benefit pulmonary function in some patients. The high technical failure and complication rates of in utero intervention should be considered before proceeding.

Female↗
PubMed1995

Use of injectable fat to obstruct the urethra in rabbits.

Bulking agents have been injected to correct urinary incontinence for at least 15 years. The injection seeks to increase bladder outlet resistance by partially obstructing the urethra and thereby reduce urinary leakage in patients with stress urinary incontinence. Although the implant is effective and requires a shorter in-hospital stay than more traditional procedures, no ideal implant substance has been discovered. To assess the effectiveness of injected fat as a bulking agent, we injected small volumes of perivesical fat into the bladder neck in New Zealand White (NZW) rabbits and tested the effect on the bladder. In eight rabbits, we harvested perivesical fat and partially closed the urethral lumen with an initial injection. A second injection 1 month later completely closed the urethral lumen. We injected six other rabbits with similar volumes of saline as controls. Two weeks after the second injection, we measured micturition frequency, bladder weight, response to electrical field stimulation, and response to bethanecol in each group. Fat implants were present at the injection site in each case 4 weeks after the first injection. Rabbits receiving fat implants had increased micturition frequency, increased bladder weight, and increased response to bethanecol and field stimulation. Previous studies have demonstrated that these changes are characteristic of mild outlet obstruction in rabbits. Injected fat can be made to close the urethra and create bladder outlet obstruction in rabbits. The short-term success of fat as a bulking agent in this experiment is encouraging and suggests the need for longer term studies.

Adipose Tissue↗
PubMed1995

Meconium hydrocele in a female newborn: an unusual cause of a labial mass.

Meconium peritonitis results from in utero perforation of the bowel and subsequent spillage of meconium into the peritoneal cavity. Free communication of the peritoneal space with the processus vaginalis during gestation permits formation of a meconium hydrocele. Meconium hydrocele has been reported in the newborn scrotum but to our knowledge there has been no previous report of meconium hydrocele in the labium of a female neonate. The predominance of meconium hydrocele in the male infant may be due to the obliteration of the processus vaginalis occurring later in the male than in the female fetus.

Female↗
PubMed1995

Ureterocele eversion with vesicoureteral reflux in duplex kidneys: findings at voiding cystourethrography.

OBJECTIVE: Ureterocele eversion refers to the sudden appearance of a bladder diverticulum at the site of ureterocele compression during voiding cystourethrography (VCUG). The radiologic appearance closely resembles a congenital bladder (paraureteral) diverticulum. Distinguishing ureterocele eversion with vesicoureteral reflux in duplex kidneys from congenital bladder diverticula with reflux is important for preoperative planning. This study describes the findings of ureterocele eversion and lower pole vesicoureteral reflux in duplex kidneys on VCUG and demonstrates how its appearance can be misleading. MATERIALS AND METHODS: Medical records, sonograms, and cystograms were reviewed retrospectively for 12 children who had VCUGs demonstrating bladder diverticula with vesicoureteral reflux and who, at surgery, had ureteroceles associated with duplex systems. Each case was assessed as to whether the finding of a diverticulum with reflux on VCUG had been correctly interpreted as ureterocele eversion with lower pole vesicoureteral reflux. RESULTS: Diagnosis of ureterocele eversion with lower pole reflux was uncertain or misinterpreted as congenital bladder diverticula with reflux in five patients in whom ureteroceles were not identifiable or in whom reflux occurred into what resembled single systems rather than lower poles of duplex systems. In two patients in whom ureteroceles were not initially identified, fluoroscopy recognized ureterocele eversion with lower pole reflux. Sonography confirmed ureterocele in one of these patients, and cystoscopy in the other. CONCLUSION: Ureterocele eversion with lower pole vesicoureteral reflux is readily diagnosed by VCUG when a ureterocele is initially identified or if the fluoroscopic appearance is typical. Ureterocele eversion with lower pole reflux can be mistaken for a congenital paraureteral diverticulum with reflux into a single collecting system if the ureterocele is small or not initially detected or if the refluxed system is not recognized as a lower pole moiety.

Child↗
PubMed1994

Ultrasound diagnosis of bladder outlet obstruction in rabbits.

One of the primary characteristics of partial outlet obstruction secondary to BPH is an increase in bladder mass commonly referred to as bladder hypertrophy. This condition has been simulated in rabbits by the partial ligation of the catheterized urethra. Ultrasonography has been utilized in both adult and pediatric urology to visualize the bladder and diagnose specific bladder disorders. The aim of the present study is to determine if ultrasonography can visualize bladder wall hypertrophy induced by obstruction. Partial outlet obstructions were created in NZW rabbits using standard methodologies, and then 5 to 7 days later, sonography was performed. The films were read by both the principal investigator and blinded investigators instructed to determine bladder wall thickness and from this predict the bladder weight. Then results were correlated with cystometrograms (CMGs) and whole bladder weights. Both the principal investigator and the blinded investigators were consistently able to distinguish obstructed from control bladders based solely on sonographic depictions of relative bladder wall thickness. In addition, the investigators were able to distinguish between low (control), medium, and high bladder weights based on sonography. The accuracy of predicting the bladder weights increased when cystosonograms were correlated with CMG studies. Thus, the degree of bladder hypertrophy can be accurately estimated by the combination of cmg and ultrasonography.

Animals↗
PubMed1994

Persistence of autologous free fat transplant in bladder submucosa of rats.

The endoscopic correction of vesicoureteral reflux is a well accepted procedure. However, the search for the ideal injectable substance continues. We compared the persistence of autologous free fat transplants from the perivesical fat pad and the abdominal wall to the bladder submucosa in an animal model. Perivesical fat consistently showed greater persistence than abdominal wall fat over time. Perivesical fat may be an ideal substance for endoscopic injection when treating vesicoureteral reflux.

Abdominal Muscles↗
PubMed1994

An immunohistochemical study of the innervation of the ureterovesical junction in infancy and childhood.

OBJECTIVE: To use histological and immunohistochemical methods to study the structure and innervation of the human ureterovesical junction (UVJ). MATERIALS AND METHODS: A series of 24 post-natal specimens taken from patients ranging in age from 1 month to 6 years were examined. Routine histological slides were stained with Masson's trichrome. In addition, an indirect immunohistochemical method was used to study the occurrence and distribution of nerves immunoreactive for the neuropeptides vasoactive intestinal polypeptide (VIP), neuropeptide Y (NPY), substance P (SP) and calcitonin gene-related peptide (CGRP). Immunoreactivity to tyrosine hydroxylase (TH), dopamine-B-hydroxylase (DBH) and to protein gene product (PGP) 9.5, a general nerve marker, were also studied. RESULTS: The UVJ comprised a ureteric muscle component (the intramural ureter) and a detrusor component (the immediately adjacent region of the urinary bladder). In the majority of specimens a third or intermediate layer was also present. This additional component consisted of tightly-packed smooth muscle cells which formed an incomplete layer that partially surrounded the juxta-vesical and intramural parts of the ureter. Numerous PGP-, VIP-, NPY, DBH- and TH- like immunoreactive (-LIR) nerves were associated with the smooth muscle bundles which comprised the intramural ureter. Such nerves ran in the connective tissue separating ureteric smooth muscle bundles and rarely coursed amongst individual smooth muscle cell comprising each bundle. SP- and CGRP- containing nerves were rarely observed in association with the intramural ureter and none were detected in the ureteric submucosa. The intermediate muscle layer was richly innervated by PGP-, TH-, DBH- and NPY- containing nerves which ran amongst the smooth muscle cells comprising this layer. VIP-, SP- and CGRP-LIR nerves were not observed within the intermediate layer. The detrusor component of the UVJ was innervated by PGP-, NPY- and VIP-LIR nerves which frequently extended between the smooth muscle cells forming the detrusor muscle bundles. TH-, DBH-, SP- and CGRP-LIR nerve fibres were rarely encountered. CONCLUSION: These findings indicate that noradrenergic nerves play a major role in the control of the ureteric component of the UVJ. In addition, the present results form baseline morphological data with which to compare the results of future studies on the structure of the UVJ in cases of vesicoureteric reflux.

Child↗
PubMed1993

The cephalotrigonal reimplant in bladder neck reconstruction for patients with exstrophy or epispadias.

A modified technique of ureteroneocystostomy with bladder neck plasty was used in 36 of 75 patients undergoing staged repair of bladder exstrophy or epispadias between 1986 and 1992. This procedure entails mobilizing the ureter while preserving the trigonal hiatus as with the cross-trigonal technique. The distal ureteral segments are directed superiorly toward the bladder dome rather than across the mid line. Of 75 patients 36 underwent cephalotrigonal reimplantation and 39 had a conventional cross-trigonal reimplant. Continence rate was 77% in the patients who underwent cephalotrigonal reimplantation and 72% in those who had a cross-trigonal reimplant. No patient had ureteral obstruction or vesicoureteral reflux. The ureter in exstrophy patients enters the bladder from an inferior position within the true pelvis. Directing the ureter superiorly rather than across the mid line provides a more gradual course through the hiatus and submucosal tunnel. The cranial course of the distal ureter frees more of the trigone for use in the rolled segment of the bladder neck and provides more muscle area for the tube. This is especially important in the patient in whom the distance between the mid prostate and trigone is particularly short.

Bladder Exstrophy↗