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Biomedical subjects

H M Snyder

Publications and source records attributed to H M Snyder.

At least 37 records · Page 2Linked to original sources
PubMed2000

The modern endoscopic approach to ureterocele.

PURPOSE: During the last 20 years the surgical approach to ureterocele has evolved from major open surgery to minimally invasive endoscopic puncture. We believe that the endoscopic approach decreases the need for open surgical procedures. We identified specific factors that predict the need for repeat surgery. MATERIALS AND METHODS: We reviewed the charts of 60 new patients with ureterocele treated with primary endoscopic incision between 1991 and 1995. Followup ranged from 4 to 62 months (mean 20). Mode of presentation, ureterocele location, associated vesicoureteral reflux and association of the ureterocele with a duplex system were evaluated. Ureterocele wall thickness was assessed subjectively via radiographic and cystoscopic methods, and categorized as thin, intermediate and thick. RESULTS: All 9 patients with a single system ureterocele had an intravesical ureterocele. No patient had associated reflux nor did any require a secondary open procedure. In 3 cases new onset ipsilateral reflux into the ureterocele spontaneously resolved. Of the 51 patients with a duplex system and associated ureterocele 19 (37%) required a secondary open procedure. The ureterocele was intravesical and ectopic in 22 (43%) and 29 (57%) cases, respectively. Reflux was associated with the ureterocele in 27 patients (53%), and 12 (44%) required a secondary open procedure. A total of 11 patients underwent ureteral reimplantation of 15 refluxing renal units and only 2 renal units required ureteral tapering. Reflux is no longer present in 14 of the 15 renal units (93%). Patients with a thick walled ureterocele required repeat puncture more frequently than those with a nonthick ureterocele. CONCLUSIONS: With the use of modern endoscopic techniques children with intravesical and single system ureteroceles require secondary open surgery less frequently than those with ectopic and duplex system ureteroceles. The mode of presentation does not predict the need for a repeat open procedure. Thick walled ureteroceles require repeat endoscopic puncture more frequently than thin and intermediate walled ureteroceles.

Female↗
PubMed2000

The anatomical approach to inguinal orchiopexy.

PURPOSE: Achieving a scrotally positioned testis with no iatrogenic atrophy is the primary goal of the surgical treatment of cryptorchidism. The success rate is associated with preoperative testicular position and the technique used. Our success rate with inguinal orchiopexy for abdominal testis is higher than those previously published and may be due to our anatomical approach to retroperitoneal dissection. We review the relevant anatomy and discuss the surgical technique of inguinal orchiopexy. MATERIALS AND METHODS: We researched and reviewed the relevant technical and anatomical literature on inguinal orchiopexy, and describe the anatomical approach to orchiopexy in detail. RESULTS: An understanding of the retroperitoneal fascial layers is the key to understanding surgery of the retroperitoneum. Dividing the internal spermatic fascia is required for the surgeon to separate the processus vaginalis from the vas and vessels. CONCLUSIONS: The average age of children undergoing cryptorchid surgery has decreased dramatically during the last 40 years. In such young patients extensive mobilization of the vas and vessels may be accomplished through a relatively small incision. We believe that our success rate with inguinal orchiopexy for abdominal testis is associated with our anatomical approach to retroperitoneal dissection.

Cryptorchidism↗
PubMed1999

An unusual subset of cryptorchidism: possible end organ failure.

PURPOSE: A paucity of germ cells exists in the cryptorchid gonad that usually correlates with a similar finding in the contralateral descended testis. However, we have noted a small number of boys with cryptorchidism in whom there is a significant difference between the histological evaluation of the cryptorchid testis and the normal descended testis that may indicate a different etiology. MATERIALS AND METHODS: From 1986 to 1991, 1,426 boys with unilateral cryptorchidism underwent orchiopexy, of whom 752 also underwent bilateral testicular biopsy. Testicular volume and position, and patency of the processus vaginalis were examined. Biopsies were fixed in 2% glutaraldehyde and embedded in Epon. Semithin tissue sections were analyzed by 2 independent investigators. The number of total germ cells, gonocytes, adult dark and pale spermatogonia, primary spermatocytes and Leydig cells was assessed. RESULTS: Of the 1,426 boys the undescended testis was on the right side in 726 and on the left side in 658 (52 versus 48%, p = 0068). Of the 752 boys who underwent bilateral biopsy 42 (5.6%) 1.1 to 16 years old (mean age plus or minus standard deviation 0 5.2 +/- 3.65) had a poor fertility index of less than 0.2 germ cell per tubule in the cryptorchid gonad, although the germ cell count in the descended testis was normal. Of the 42 testes in this special group of boys 30 (71%) were on the right side (Fisher's exact test p <0.23), including 16 (38%) in an intra-abdominal or high canalicular position. The processus vaginalis was patent in 86% of the intra-abdominal testes and in 100% of those located at the tubercle but in only 25% of those in a pre-scrotal position. While average germ cell count in the cryptorchid testis was 0.06 per tubule with abnormal germ cell maturation, number was normal (greater than 2 germ cells per tubule) in the contralateral descended testis with a normal distribution of adult dark and pale spermatogonia, and primary spermatocytes. Average volume of the cryptorchid testis was significantly less than that of the descended testis (1.20 +/- 0.35 versus 1.60 +/- 0.68 mm.3, p <0.0001). CONCLUSIONS: Based on the normal scrotal testis the fertility prognosis is good in this small subgroup of boys with cryptorchidism. Rather than the usual endocrinopathy of cryptorchidism, the undescended testis in these boys may be the result of end organ failure. These patients with favorable fertility potential may be recognized only if each testis is biopsied at unilateral orchiopexy.

Adolescent↗
PubMed1999

Prognostic factors for long-term renal function in boys with the prune-belly syndrome.

PURPOSE: Renal failure develops in 25 to 30% of patients with the prune-belly syndrome. The clinical parameters associated with renal failure in this condition are not well understood. We determined which factors predict renal failure in children with the prune-belly syndrome. MATERIALS AND METHODS: We reviewed the records of 35 patients with the prune-belly syndrome who were treated at our hospital during a 37-year period. Nadir serum creatinine, time to nadir creatinine, presence or absence of a patent urachus, presence and severity of urinary tract infection, and renal failure were analyzed. RESULTS: Mean followup was 14 years 2 months. In 2 of the 17 patients with a nadir serum creatinine of less than 0.7 mg./dl. renal failure developed. Each of these 2 children also had clinical pyelonephritis and urosepsis. In 12 of the 13 patients nadir serum creatinine greater than 0.7 mg./dl. strongly predicted renal failure. Nonfebrile urinary tract infection within the first year of life was not predictive of outcome (p = 0.8) but a history of clinical pyelonephritis correlated with eventual renal failure (p<0.001). Urosepsis also correlated with renal failure (p = 0.008). Children with at least 1 normal kidney on renal ultrasound or renal scan had a significantly lower chance of renal failure (p<0.001). CONCLUSIONS: Bilaterally abnormal kidneys on ultrasound or renal scan, a nadir serum creatinine of greater than 0.7 mg./dl. and clinical pyelonephritis are prognostic for renal failure.

Adolescent↗
PubMed1998

Comparison of dermal and epithelial approaches to laser tissue soldering for skin flap closure.

BACKGROUND AND OBJECTIVE: Prior studies of laser tissue soldering (LTS) of epithelial skin have shown poor wound strength in the short-term; however, we hypothesize that greater tensile strength and healing properties will result from directing laser energy to the dermal aspect of the skin. The current study compares wound strength and histology in a rat skin flap model of epithelial and dermally applied LTS. STUDY DESIGN/MATERIALS AND METHODS: Skin flaps (2.5 x 4 cm) were raised and bisected on the dorsum of Sprague-Dawley rats. The center line of bisection was closed from a dermal approach by LTS (LTS-D, diode laser 15.9 W/cm2 + Columbia solder), the upper incision by epithelial LTS (LTS-E), and the lower incision by suturing (7-0 Vicryl). Wound skin strips (1-2 mm x 10 mm) were studied immediately (N = 14) and at 3 (N = 57), 7 (N = 31), and 10 (N = 28) days postoperatively and were subjected to tensiometric analysis. Histologic staining with hematoxylin and eosin and Mallory's trichrome methods were used to define wound architecture. RESULTS: No wound dehiscences were noted in any group. Greater immediate tensile strength was noted in wounds closed by LTS-D (521 +/- 61 g/cm2) versus LTS-E (342 +/- 65 g/cm2); however, this difference was not statistically significant (P = .08). By 3 days, both LTS-D (476 +/- 55 g/cm2) and LTS-E (205 +/- 37 g/cm2) maintained their initial strength; however, LTS-D and sutured (436 +/- 49 g/cm2) wounds were stronger (P < .05) than LTS-E. At 7 and 10 days, LTS-D (2,433 +/- 346 g/cm2 and 3,100 +/- 390 g/cm2) showed superior tensile strength (P < .05) compared to both LTS-E (1,542 +/- 128 g/cm2 and 2,081 +/- 219 g/cm2) and suturing (1,342 +/- 119 g/cm2 and 1,661 +/- 115 g/cm2). Histologic analysis of LTS-D wounds at 3 days showed full-thickness tissue apposition, complete epithelialization, and minimal inflammation or thermal injury. At 7 days, solder was present in the wounds. In contrast, LTS-E wounds at 3 days displayed lack of epithelialization secondary to thermal injury and partial-thickness tissue apposition. However by 7 days, epithelialization was complete with moderate scarring, and no solder was seen. Sutured samples appeared similar to LTS-D, except for poorer tissue apposition at the hypodermis. CONCLUSION: Our results show that skin flap wound healing after dermal LTS is superior to epithelial LTS and emphasizes the importance of site specificity in the utilization of this operative technique in reconstructive surgery.

Albumins↗
PubMed1998

Surgical management of the nonpalpable testis: the Children's Hospital of Philadelphia experience.

PURPOSE: The management of the nonpalpable testis permits an individualized operative approach. We analyze the results of surgical management of a large series of patients with a nonpalpable testis. MATERIALS AND METHODS: Between January 1986 and June 1994 we treated 1,866 boys with undescended testes. There were 447 testes (24%) that were not palpable at presentation. Intra-operative data on these patients were collected for age at presentation, bilateral testes position, testicular size, associated inguinal anomalies (vas, epididymis and processus vaginalis) and surgical approach. For intra-abdominal testes postoperative results of 2 surgical techniques, the Fowler-Stephens procedure and Koop orchiopexy (retroperitoneal mobilization of spermatic vessels and vas) were compared in 76 patients with at least 18 months of followup. RESULTS: Average patient age at presentation was 34 months with 63% presenting before age 48 months. Of the impalpable testes 58% were on the left side, 35% were on the right side and 7% were bilateral. At operation 181 testes (41%) were atrophic or absent, 91 (20%) were intra-abdominal with 14 (3.1%) bilateral, 136 (30%) were in the inguinal canal and 39 (9%) were in other locations, including 22 at the pubic tubercle, 2 in the upper scrotum, 13 in the superficial inguinal pouch and 2 in the perineum. Of the intra-abdominal group associated extratesticular malformations were identified in 36 cases (39%). Attachment of the vas deferens to the testis was abnormal in 23 of 64 cases (36%), including 10 that were completely detached and 13 with head or tail attachment only. Of the 91 evaluable cases in the intra-abdominal group 38 (42%) had been treated with the Fowler-Stephens repair (5 in 2 stages), 33 (36%) with inguinal orchiopexy and intraperitoneal dissection without dividing the spermatic vessels, 5 with 2-stage procedures and vessel preservation and 14 (15%) with orchiectomy. One testis was left in situ. The inguinal approach with intraperitoneal extension was successful in defining the testis location or blind-ending vas and vessels in 100% of the cases. A single operation to perform orchiopexy was successful in 92% of the cases. Overall, results were considered excellent or acceptable in 32 of 33 cases (97%) after Koop orchiopexy and 28 of 38 (74%) after the Fowler-Stephens orchiopexy. CONCLUSIONS: Nonpalpable testes accounted for 24% of the patients presenting with undescended testes. At surgical exploration 39% of impalpable testes were distal to the external inguinal ring, 41% were atrophic or absent and 20% were intra-abdominal. All cases were treated through a standard inguinal incision. These data provide evidence that the inguinal approach to orchiopexy with transperitoneal mobilization of the vas and vessels without transection is highly successful for the intra-abdominal cryptorchid testis and, to date, is the preferred technique for the management of the intra-abdominal undescended testis.

Child, Preschool↗
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

Developmental expression of interstitial collagen genes in fetal bladders.

Bovine bladders at 3 stages during fetal development were examined for expression of collagens by immunohistochemistry as well as by measurement of steady state mRNA levels. Expression of type I and type III collagens during the fetal period was compared with that of adult cows as well as a young animal (heifer). Each bladder was separated into a detrusor and a urothelial-lamina propria sample which were then analyzed separately. Distribution and fiber arrangement of types I and III collagens were different depending upon the region of the bladder wall examined. Type III collagen, in particular, has a "coiled" appearance which is especially prominent within the lamina propria. Collagen gene expression showed a distinctive pattern which was different for both type I and type III collagen. While type I collagen gene expression peaked during the late second to early third trimester, type III collagen expression progressively decreased throughout the fetal period. In addition, expression of both collagens was greater in the urothelial-lamina propria fractions. These data demonstrate that the pattern of collagen gene expression in the developing bladder is developmentally regulated and is unique to each of the two major structural layers.

Animals↗
PubMed1997

Active and passive compliance of the fetal bovine bladder.

PURPOSE: Others have shown that the fetal bovine bladder is relatively noncompliant. Previous studies on compliance of fetal bovine bladders have demonstrated that the youngest fetal bladders had lowest and the oldest fetal bladders (near full-term) had greatest compliance. Our study was designed to determine the level of participation of active tension in the compliance of fetal bladders during gestation. MATERIALS AND METHODS: Fetal bovine bladders were obtained immediately after maternal harvest and crown-to-rump length was measured to determine gestational age. The fetus was inspected for genitourinary anomalies and the bladder was immediately placed in chilled M199 media. Strips (1 x 0.5 cm.) were excised from the anterior sagittal plane of the bladder and subjected to length-tension analysis in oxygenated Tyrode's buffer at 37C. Tension was measured using a force transducer and length was increased using a micropositioner. Compliance refers to the length-tension studies performed in normal Tyrode's solution and consists of a combination of active (smooth muscle tone) and passive properties. Passive compliance refers to length-tension studies performed after inactivation of bladder smooth muscle tone. Compliance with muscle tone intact was determined by incrementally stretching the strips to twice resting length in physiological buffer and then permitting them to return to resting length. Passive compliance with muscle tone ablated was determined in the same fashion after overnight incubation in calcium-free Tyrode's buffer in the presence of 5 mM. egtazic acid and 10 mM. sodium azide. An exponential function was fit to the normalized length-tension curves, where the exponential coefficient (EC) is numerically inversely proportional to compliance. RESULTS: Passive compliance was greatest in the youngest bladders (EC = 0.5 in the first trimester) and gradually decreased with increasing fetal age (EC = 1.2 in the third trimester). Active compliance demonstrated the opposite pattern, since the younger bladders were more stiff (EC = 2.1 in the first and 1.6 in the third trimesters). CONCLUSIONS: These studies demonstrate that passive compliance is greatest in the youngest bladders and progressively decreases with gestation. However, active smooth muscle tone is greatest in the youngest bladders and decreases with gestation. Thus, high active smooth muscle tone in the youngest fetal bladders results in relatively poor compliance of the early stage fetal bladder.

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

Pediatric Vesicoureteral Reflux Guidelines Panel summary report on the management of primary vesicoureteral reflux in children.

PURPOSE: The American Urological Association convened the Pediatric Vesicoureteral Reflux Guidelines Panel to analyze the literature regarding available methods for treating vesicoureteral reflux diagnosed following a urinary tract infection in children and to make practice policy recommendations based on the treatment outcomes data insofar as the data permit. MATERIALS AND METHODS: The panel searched the MEDLINE data base for all articles from 1965 to 1994 on vesicoureteral reflux and systematically analyzed outcomes data for 7 treatment alternatives: 1) intermittent antibiotic therapy, 2) bladder training, 3) continuous antibiotic prophylaxis, 4) antibiotic prophylaxis and bladder training, 5) antibiotic prophylaxis, anticholinergics and bladder training, 6) open surgical repair and 7) endoscopic repair. Key outcomes identified were probability of reflux resolution, likelihood of developing pyelonephritis and scarring, and possibility of complications of medical and surgical treatment. RESULTS: Available outcomes data on the various treatment alternatives were summarized in tabular form and graphically, and the relative probabilities of possible outcomes were compared for each alternative. Treatment recommendations were based on scientific evidence and expert opinion. The panel concluded that only a few recommendations can be derived purely from scientific evidence of a beneficial effect on health outcomes. CONCLUSIONS: For most children the panel recommended continuous antibiotic prophylaxis as initial treatment. Surgery was recommended for children with persistent reflux and other indications, as specified in the document.

Child↗
PubMed1996

Frontonasal malformation and cloacal exstrophy: a previously unreported association.

We report on a child with frontonasal malformation (FNM) and cloacal exstrophy, a combination of findings that have not been reported previously. In FNM and cloacal exstrophy, associated malformations are rare. FNM and cloacal exstrophy both represent abnormalities of the development of the midline field; this combination of anomalies in this patient suggests an impairment of caudal and cranial midline development during blastogenesis.

Abnormalities, Multiple↗
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↗