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Biomedical subjects

Arthur D Smith

Publications and source records attributed to Arthur D Smith.

At least 19 recordsLinked to original sources
PubMed2006

Novel dual-lumen ureteral stents provide better ureteral flow than single ureteral stent in ex vivo porcine kidney model of extrinsic ureteral obstruction.

OBJECTIVES: In the instance of extrinsic ureteral obstruction, indwelling ureteral stents have a high failure rate. Although technically challenging, simultaneous insertion of two ipsilateral stents can achieve better flow rates with time. A novel dual-lumen stent, composed of two adhered ureteral stents, offers the additional benefit of easier placement than a single guidewire. Using a novel ex vivo porcine model, the flow rates within an extrinsically obstructed renal unit were evaluated using two internal ipsilateral stents and two prototype double-lumen stents. METHODS: Sixteen renal units were harvested from eight adult Yorkshire female pigs. To quantify flow, the kidneys were infused at a constant pressure, and the corresponding ureteral drainage was measured for a defined interval. The flow was measured with a standard 7F double-pigtail stent, two ipsilateral 7F double-pigtail stents, a 7F novel double-lumen stent designed with both distal lumens open, and a 7F novel double-lumen stent with one distal lumen closed. The intraluminal and extraluminal flow in obstructed and nonobstructed systems was measured. RESULTS: The two ipsilateral standard stents or prototype double stents achieved better flow down the ureter than did one standard stent (P <0.05). The intraluminal and extraluminal flow in the novel stents was statistically greater than the corresponding flow in the standard double-pigtail stent (P <0.01). The extraluminal and obstructed flow was lowest for the standard double-pigtail stent. CONCLUSIONS: Novel dual-lumen prototype ureteral stents provided better flow than a single stent in extrinsically obstructed ureters with the proposed added benefit of easier retrograde insertion compared with a single guidewire.

Animals↗
PubMed2006

Hand pain during hand assisted laparoscopic nephrectomy--an ischemic event?

PURPOSE: The etiology of hand discomfort during hand assisted laparoscopic nephrectomy may be ischemic in nature. We determined if pneumoperitoneal pressure sustained to the hand during hand assisted laparoscopic nephrectomy poses an occupational risk, contributing to local hand hypoxia and resultant extremity pain. MATERIALS AND METHODS: A total of 442 measurements of hand oxygen saturation were made during hand assisted laparoscopic nephrectomy. A Nellcor OxiMax Max-1 oxygen sensor was attached to the left index finger of each surgeon and hand assisted laparoscopic nephrectomy was performed using a LapDisc at 15 mm Hg pneumoperitoneal pressures. Local hand oximetry readings and a numerical pain distress scale (range 0 to 10) were recorded every 2 minutes. To control for motion artifact oximetry readings were taken during hand motion and at rest. The Student t test was used to compare differences in local hand oxygen saturation and hand pain in and between study groups. RESULTS: A history of hand pain during hand assisted laparoscopic nephrectomy was significantly associated with local hypoxia during operative motion and at rest (p = 0.023 and 0.012, respectively), even with an adequate fascial incision and standard pneumoperitoneal pressures. During hand assisted laparoscopic nephrectomy hand pain was most significantly associated with local hypoxia after 24 minutes (p = 0.0002), when local oxygen saturation was 56% to 88%. CONCLUSIONS: A cohort of urologists is predisposed to ischemic hand pain during hand assisted laparoscopic nephrectomy. The etiology of this pain may be hypoxic in nature, attributable to pneumoperitoneal pressure decreasing perfusion and causing venous congestion or regional local ischemia. Circumferential antebrachial constriction from the LapDisc does not seem to be a significant contributing factor in the presence of an adequate fascial incision. Hand pain secondary to ischemia is most significant after 24 minutes at 15 mm Hg. Future studies in more subjects are called for to validate these findings to elucidate which surgeons are predisposed to this potential occupational hazard and what perioperative measures can be taken to avoid hand pain during hand assisted laparoscopic nephrectomy.

Adult↗
PubMed2005

"Angular percutaneous renal access". Multiple tracts through a single incision for staghorn calculous treatment in a single session.

PURPOSE: We herein describe the technique of a single subcostal skin incision with multiple angular punctures to approach the superior, middle and lower pole of the kidney for the management of staghorn calculi. MATERIALS AND METHOD: One hundred patients with staghorn calculi were managed between January 1997 and June 2000. The superior calyx was approached by a subcostal triangulation technique and the middle and lower calyces were approached by angular punctures. Correct advancement of the needle was monitored by biplane fluoroscopy. Maximum effort was made for complete stone clearance in a single session. RESULTS: : 87% patients were rendered stone free in a single session. The average number of tract dilation per renal unit was 2.4 with an average anesthesia time of 110 minutes and the average blood loss of 450 ml. The average hospital stay duration was 4.6 days. The secondary procedures required were 0.11 per patient and the complication rate totalled 7% with one case of excessive hemorrhage requiring embolization. CONCLUSIONS: We therefore propose the triangulation technique as a safe and appealing method for the percutaneous management of staghorn calculi.

Humans↗
PubMed2005

Trends in ureteropelvic junction obstruction management among urologists in the United States.

OBJECTIVES: To determine current practice patterns in the surgical treatment of ureteropelvic junction obstruction (UPJO) among urologists in the United States. METHODS: Using the American Urological Association directory, an electronic mail survey regarding the surgical management of UPJO was sent to 1040 urologists in the United States with an electronic mail address listed in the roster. RESULTS: The response rate was 37.6%. Of the respondents, 67.4% were in community practice and 32.6% in academic practice. Nearly 53% of the respondents would perform a workup for a crossing vessel before definitive therapy; if no crossing vessel was found, 43.5% would consider Acucise endopyelotomy as the first-line procedure. However, if a crossing vessel was found, 57.4% would perform open pyeloplasty and 34.3% would choose laparoscopic pyeloplasty as their first-line procedure. If pyeloplasty was chosen, community urologists preferred open pyeloplasty (77.6%), and academic urologists preferred laparoscopic pyeloplasty (66.9%). The surgeon's training and experience was the most influential factor in choosing between laparoscopic and open pyeloplasty. If the patient had a failed endopyelotomy in the past, most respondents (90.8%) would perform pyeloplasty for definitive treatment of the UPJO. CONCLUSIONS: Demonstration of a crossing vessel remains an important factor in determining the course of management of a UPJO. During the past 5 years, a growing number of urologists in both academic and nonacademic practices have been performing laparoscopic pyeloplasty for the management of UPJO in adults. Several factors, especially the surgeon's training, have an impact on the choice of procedure. Open pyeloplasty is still performed by a significant number of urologists. These data may be useful in designing physician education programs and/or future investigations to help define standard treatment practices for UPJO.

Adult↗
PubMed2005

Laparoscopic pyeloplasty versus antegrade endopyelotomy: comparison in 100 patients and a new algorithm for the minimally invasive treatment of ureteropelvic junction obstruction.

The aim of this article is to assess the treatment efficacy of percutaneous endopyelotomy and laparoscopic pyeloplasty to establish a new algorithm in the minimally invasive treatment of ureteropelvic junction obstruction (UPJO). Hospital records, office charts, and radiographic studies of patients with UPJO treated either endoscopically (n = 50), laparoscopically (n = 50), or by endopyeloplasty (n = 5) were reviewed. All percutaneous endopyelotomies were performed with a cold hook-knife technique, and all laparoscopic pyeloplasties were performed transperitoneally using an Anderson-Hynes dismembered anastomosis. Successful outcomes were defined as relief of obstruction as quantified by diuretic renal scans and/or relief of obstructive symptoms. All patients were followed for an average of 16.0 months (range, 2 to 42 months). In the endoscopically treated group, the average age was 44.6 +/- 15.6 years, estimated blood loss (EBL) was 152.1 +/- 112.8 mL, and the hospital stay was 2.5 +/- 1.0 days. There was no significant change from preoperative to postoperative creatinine (1.2 +/- 0.7 mg/dL to 1.2 +/- 0.7 [106 +/- 62 micromol/L +/- 106 +/- 62 micromol/L]). Success rates included 92% (35 of 38) for primary percutaneous antegrade endopyelotomy and 58% (7 of 12) for secondary percutaneous antegrade endopyelotomy. All of the primary percutaneous antegrade endopyelotomy failures (n = 3) had either grade 3 or grade 4 hydronephrosis. In the laparoscopic pyeloplasty group the average age was 37.9 +/- 14.8 years, EBL was 108.3 +/- 109.4 mL, and the average hospital stay was 2.6 +/- 0.9 days. There was no significant change from preoperative to postoperative creatinine (1.1 +/- 0.4 mg/dL to 1.0 +/- 0.4 mg/dL [97 +/- 35 micromol/L to 97 +/- 35 micromol/L]). Success rates included 100% (29 of 29) for primary repair and 95.2% (20 of 21) for secondary repair. There was no statistical difference in preoperative patient parameters or objective outcomes when comparing primary endopyelotomy and primary laparoscopic pyeloplasty. In skilled hands, highly successful outcomes can be expected when either antegrade endopyelotomy or laparoscopic pyeloplasty is used to treat a primary UPJO. In the instance of a UPJO associated with a high degree of hydronephrosis, patients may be better served with a laparoscopic pyeloplasty. To maximize an efficacious outcome, minimally invasive UPJO treatment decisions should be based on patient and surgeon preference, as directed by the presented algorithm.

Adult↗
PubMed2005

Endourologic treatment of upper urinary tract transitional cell carcinoma.

The traditional treatment for upper tract transitional cell carcinoma (UTTCC) consists of radical nephroureterectomy. A more conservative approach, however, was required in cases of bilateral UTTCC and in patients with disease in a solitary kidney but who had underlying comorbidities that made them unsuitable candidates for open surgery. Minimally invasive treatment methods were developed for these select groups of patients. Because of technological advancements and refinement in endoscopic techniques, most patients with UTTCC, even those with normal contralateral kidneys, can now be offered minimally invasive treatment with single or multimodal approaches involving ureteroscopy or percutaneous resection. For patients with low-stage, low-grade UTTCC, five-year survival rates are comparable for those treated endourologically and those treated by nephroureterectomy. High-grade lesions have much higher recurrence and progression rates than lower-grade lesions, and nephroureterectomy is therefore recommended in patients with high-grade disease. The use of adjuvant instillation in the treatment of UTTCC, administered via antegrade and retrograde methods, has been shown to improve outcomes. For recurrences to be diagnosed and treated in a timely manner, and acceptable cancer-free survival rates maintained, long-term rigorous follow-up after endourologic treatment, with regular surveillance ureteroscopy, is crucial.

Administration, Intravesical↗
PubMed2005

First prize: ureteral segmental replacement revisited.

BACKGROUND AND PURPOSE: Long strictures of the proximal ureter are difficult to manage, and circumferential replacement with various natural and synthetic materials has been unsuccessful. We sought to use cultured autologous cells seeded onto graft material for proximal-ureteral replacement. Additionally, we wished to determine if urothelial cell-seeded de-epithelialized small bowel would generate adequate ureteral replacement. MATERIALS AND METHODS: Three sets of experiments were performed. First, autologous pig-bladder smooth-muscle and urothelial cells were expanded in culture on large sheets of multilayer small-intestinal submucosa (SIS). These sheets were then tubularized and used to replace a 5-cm segment of proximal ureter in pigs. Second, autologous cells harvested from the bladders of Beagle dogs were cultured and seeded on porcine ureteral acellular matrix, which was used to replace a 3-cm segment of ureter in dogs. Segments were wrapped in omentum to enhance vascularity. Third, a de-epithelialized small-bowel segment seeded with autologous bladder-epithelial cells was transversally retubularized (Monti) into a 4-cm ureteral replacement. Follow-up studies consisted of retrograde pyelography, serum chemistry assays, hematoxylin/eosin studies, and immunohistopathologic examination using antibodies against alpha-smooth-muscle actin and pancytokeratin AE1-AE3. RESULTS: Coculture of urinary-tract cells on large segments of SIS failed to create adequate ureteral replacement. All grafts were contracted and stenotic, with complete obstruction of the ipsilateral renal unit. Similar results were seen in the Beagles. Despite clinical obstruction and gross contraction of the graft, a circumferential muscular ureteral wall lined with multilayer transitional epithelium was present. Urotheliumseeded de-epithelialized Monti bowel segments resulted in patent ureteral replacement without hydroureteronephrosis and with normal renal function, serum electrolytes, and acid-base balance. However, bowel mucosa fully regenerated, with multilayer transitional epithelium growing adluminally in continuity with the proximal and distal anastomotic sites. CONCLUSIONS: Seeding of ureteral grafts with autologous bladder cells does not promote success in two largeanimal models using different xenogenic acellular matrices. However, muscle and urothelium regeneration occurs with ureteral acellular matrix in the dog. Urothelium-seeded de-epithelialized Monti bowel segments may be an acceptable substitute for long proximal ureteral segments. Further technical refinements are required to replace the bowel mucosa completely with normal urothelium.

Animals↗
PubMed2005

Effects of pneumoperitoneal gases and pressures on transitional cell carcinoma adhesion, growth, apoptosis and necrosis: an in vitro study.

PURPOSE: We studied the effects of insufflation gas and pressure on the adhesion, growth, apoptosis and necrosis of transitional cell carcinoma (TCC) in an in vitro model. MATERIALS AND METHODS: Tumor adhesion and cell growth of AY-27 rat TCC was measured after 3-hour incubation with CO2, N2 and He insufflation at different pressures (0, 10 and 15 mm Hg) in vitro. The effects of these gases on the rate of tumor cell apoptosis and necrosis were compared. RESULTS: In vitro the tumor adhesion rate was lowest with CO2 and highest with N2. Higher gas pressures resulted in decreased adhesion rates for CO2 and He but increased adhesion rates for N2. N2 enhanced tumor cell proliferation at all pressures studied. He and CO2 resulted in an initial increase in cell proliferation in the first 24 hours, followed by a decrease in tumor growth. Extracellular medium turned acidic in CO2 (pH 6.27 to 6.39) but basic in N2 and He (pH 8.39 to 8.84). At all insufflation pressures studied apoptosis and necrosis rates were increased in the first 24 hours, followed by a decrease for CO2 and N2. He resulted in increasing apoptosis and necrosis throughout the study period. CONCLUSIONS: The type of gas and insufflation pressure affects cell adhesion and tumor growth. There was a significant increase in tumor adhesion and proliferation with N2 insufflation compared with CO2 and He at 0 to 15 mm Hg pressures. CO2 demonstrated the greatest decrease in TCC adhesion and proliferation at 15 mm Hg pressure. Apoptosis and necrosis were highest for He compared with the other gases.

Animals↗
PubMed2004

Correlation of ureteroscopic appearance with histologic grade of upper tract transitional cell carcinoma.

OBJECTIVES: To correlate urologists' impressions of the tumor grade of upper tract tumors at ureteroscopy with the histologic findings after biopsy or resection. METHODS: A retrospective review of all patients who underwent diagnostic or therapeutic ureteroscopy for upper tract transitional cell carcinoma (TCC) between 1992 and 2002 was performed. Only patients who had proven TCC with a descriptive narration of the urologists' impressions of tumor grade and a representative pathologic specimen were included. The urologist's impression of tumor grade was reported as low or high grade according to the operative report and was correlated with the histologic grade. A total of 40 tumors met inclusion criteria. RESULTS: Ureteroscopy classified 28 tumors as low grade, 10 as high grade, and 2 as benign. The histologic findings of the 28 tumors believed to be low grade on ureteroscopy showed that 20 (71%) were grade 1-2, and of the 10 tumors believed to be high grade, 8 (80%) were actually grade 3-4. The overall accuracy of ureteroscopy in predicting the tumor grade of upper tract TCC was 70%. The benign-appearing lesions proved to be malignant. CONCLUSIONS: The urologists' impressions of tumor grade on ureteroscopy were relatively good. However, visual assessment alone was inaccurate in 30% of the cases in our series. Therefore, we believe that biopsies remain essential for accurate grading of upper tract TCC. Therapeutic decisions should not be based solely on visual ureteroscopic assessment of tumor appearance.

Biopsy↗
PubMed2004

Ureteropelvic junction obstruction repair: when, how, what?

PURPOSE OF REVIEW: To review factors that affect the success of ureteropelvic junction obstruction repair and recent developments in minimally invasive procedures for the repair of ureteropelvic junction obstruction. RECENT FINDINGS: Recent reports and studies further confirm earlier findings that the success rate of endopyelotomy is decreased when a crossing vessel is the primary cause of ureteropelvic junction obstruction, poor renal function and significant hydronephrosis. Various minimally invasive procedures have emerged recently for the treatment of ureteropelvic junction obstruction. These include laparoscopic pyeloplasty, robotically assisted laparoscopic procedures, and percutaneous endopyeloplasty. These procedures offer potential advantages over conventional endopyelotomy, including better success rates in the presence of crossing vessels, wider caliber reconstruction of the ureteropelvic junction, and full-thickness healing with primary intent. SUMMARY: With such a large variety of minimally invasive procedures for the treatment of ureteropelvic junction obstruction available, the treatment choice for ureteropelvic junction obstruction must be based on several factors, including the success and morbidity of the procedures, the surgeon's experience, the cost of the procedure, and the patient's choice.

Age Factors↗
PubMed2004

Peritoneal and systemic inflammatory mediators of laparoscopic bowel injury in a rabbit model.

PURPOSE: Unrecognized bowel injury following laparoscopy has a subtle and delayed clinical presentation compared with that after open surgery. We determined peritoneal and systemic immune function in laparoscopic and open bowel injury cases. We propose that laparoscopy does not activate immune responses to the same extent as open surgery. MATERIALS AND METHODS: A total of 40 rabbits were divided into 4 groups. Two study groups were subjected to laparoscopic and open bowel injury, and 2 control groups underwent pneumoperitoneum and sham open surgery, respectively, without bowel injury. Animals were sacrificed 1 day, 3 days and 1 week postoperatively. Macroscopic and histological findings were analyzed. Peritoneal fluid, systemic white blood count (WBC) and differentials were done with a hemocytometer. Peritoneal fluid and serum interleukin (IL)-8 concentrations were measured by enzyme-linked immunosorbent assay. RESULTS: Macroscopic and histological findings were indistinguishable in the 2 study groups. However, study groups demonstrated higher peritoneal WBCs than their respective controls at 1 and 3 days (p <0.05). Peritoneal WBC was lower in the laparoscopy than in the open study group at 3 days (p <0.05). There was a significant decrease in peritoneal lymphocytes and monocytes in the laparoscopic vs the open study group at 3 days. No differences were found in systemic WBC or differentials among all groups. Peritoneal IL-8 concentrations were higher in the laparoscopic bowel injury than in the laparoscopic control group at 1 and 3 days (p <0.05). However, there were no differences in peritoneal or serum IL-8 concentrations between both study groups. CONCLUSIONS: Laparoscopic surgery seems to be unable to sustain peritoneal immune responses, which may mask reliable clinical signs and symptoms of peritonitis associated with bowel injury.

Animals↗
PubMed2003

Electrical prostate morcellator: an alternative to manual morcellation for laparoscopic nephrectomy specimens? An in vitro study.

OBJECTIVES: To compare the safety and efficacy of morcellation with the electrical prostate morcellator (EPM) or manual morcellation of the kidney, using an internal view within the morcellation sac. METHODS: Thirty porcine kidneys, mean renal mass 174.5 g, were divided into three groups of 10. All morcellations were performed inside the LapSac. Groups 1 and 2 underwent morcellation using the EPM, monitored inside the LapSac using the nephroscope and outside the LapSac with the laparoscope, respectively. Group 3 underwent manual morcellation with ring forceps. The groups were assessed for morcellation time, fragment size, and LapSac integrity. RESULTS: In group 1, one pinhole perforation occurred; in group 2, nine perforations occurred (five large and four pinhole). No perforations occurred (P <0.001) in group 3 (manual morcellation). The mean morcellation time for groups 1 through 3 was, respectively, 86.9, 47.1, and 15.1 minutes (P <0.0001). The corresponding mean fragment size was 0.011, 0.015, and 1.36 g. The difference in mean fragment size was significantly different between the manual morcellation group and the EPM groups (P <0.001), but not between the two EPM groups (P = 0.12). CONCLUSIONS: Manual morcellation was safe, fast, and superior to morcellation with the EPM monitored either inside or outside the LapSac. The high rate of LapSac perforation precludes the use of EPM after laparoscopic radical nephrectomy in the clinical forum.

Animals↗
PubMed2003

Practice trends in contemporary management of adult ureteropelvic junction obstruction.

OBJECTIVES: To determine current practice patterns in the surgical treatment of ureteropelvic junction obstruction in the United States and Canada. METHODS: An e-mail survey was sent to 56 academic endourologists regarding the number of procedures performed in the previous year for ureteropelvic junction obstruction, factors considered in the choice of procedure, and whether community urologists in their area were performing laparoscopic pyeloplasty or endopyelotomy. RESULTS: The response rate was 66% (37 of 56). More respondents were performing endopyelotomy (91%) than laparoscopic pyeloplasty (51%), and nearly one half were performing open pyeloplasty. The mean number of procedures performed by respondents in the previous year was 9.5 endopyelotomies, 4 laparoscopic pyeloplasties, and 2.5 open pyeloplasties. A number of factors had an impact on the practitioners' choice of procedure, including the presence of a crossing vessel and massive hydronephrosis, secondary ureteropelvic junction obstruction, the surgeon's training, procedure cost, operative time, expected success rate, degree of invasiveness, and patient preference. Nearly one fifth of respondents said they would choose laparoscopic pyeloplasty as first-line therapy regardless of anatomic considerations. Seventy-eight percent stated that community urologists in their area were performing endopyelotomy routinely or occasionally compared with only 3% who stated community urologists in their area were performing laparoscopic pyeloplasty. CONCLUSIONS: Laparoscopic pyeloplasty is still in its early stages. Although laparoscopic pyeloplasty has a greater success rate, endopyelotomy continues to be more commonly performed in academic centers. Laparoscopic pyeloplasty has not yet made significant inroads into community practice. Several factors, especially the surgeons' training, have an impact on the choice of procedure. Open pyeloplasty is still performed by a significant number of academic endourologists.

Academic Medical Centers↗
PubMed2003

Comparison of the mechanical, flow, and optical properties of contemporary flexible ureteroscopes.

OBJECTIVES: New designs have improved the ability of flexible ureteroscopes to assess the upper urinary tract. However, limitations of tip deflection may interfere with diagnosis and treatment of lower pole renal pathologic features and smaller working channels may impair irrigant flow. Our purpose was to compare the new flexible ureteroscopes with prior models to determine whether engineering advances have overcome these problems. METHODS: Two newly released flexible ureteroscopes, the ACMI DUR-8 Elite and the Storz 11278AU, were compared with four other ureteroscopes, the ACMI DUR-8, Storz 11274AAU, Olympus URF-P3, and Wolf 9F. Active tip deflection, irrigation flow rates, and intraluminal pressures with and without various endoscopic tools were assessed. The specifications, purchase prices, and repair costs were obtained from the individual manufacturers. Also, the field of view and screen image size of each scope were compared. RESULTS: The ACMI DUR-8 Elite and Storz 11278AU had improved tip deflection of 79 degrees and 144 degrees, respectively, from previous ureteroscopes. Although the tip deflections of all ureteroscopes were compromised by the insertion of endoscopic tools, new ureteroscopes were less affected. With a 3F basket within the working channel, the ACMI DUR-8 Elite and the Storz 11278AU had a loss of downward deflection of only 0.7% and 2.8% compared with a loss of 9.6% and 5.0% for their older models, respectively. However, the flow rate of these new instruments was decreased. CONCLUSIONS: The new flexible ureteroscopes have significantly better active tip deflection than previous models, both with and without endoscopic instrumentation inserted. However, improved flexibility comes at the expense of a decreased flow rate.

Equipment Design↗