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Biomedical subjects

Patrick S Lowry

Publications and source records attributed to Patrick S Lowry.

8 recordsLinked to original sources
PubMed2005

Obstruction alters the effect of prostaglandin E2 on ureteral contractility.

BACKGROUND AND PURPOSE: Although our understanding of ureteral physiology during acute obstruction remains limited, we believe that prostanoids (prostaglandins [PGs], thromboxanes, prostacyclins) play a major role in modulation of ureteral contractility and that inhibition of prostanoid synthesis causes substantial reduction in in-vitro and in-vivo ureteral contractility rates. The purpose of this study was to determine the in-vitro effects of PGE2 on chronically obstructed human and acutely obstructed porcine ureters. MATERIALS AND METHODS: Female pigs underwent unilateral laparoscopic ureteral obstruction. Following 1, 2, 6, 24, and 48 hours of obstruction (n = 3 at all points), animals were euthanized, and obstructed, contralateral nonobstructed, and normal (from unobstructed pigs) ureters were harvested. Chronically obstructed human ureter was obtained from subjects who underwent nephrectomy to remove nonfunctioning kidneys. Normal human ureter was obtained from the discarded portion of excess distal ureter in patients undergoing elective donor nephrectomy. Rings 4 to 5 mm long were suspended in aerated Krebs buffer, and their spontaneous contractions and contraction in response to various concentrations of PGE2 were recorded. RESULTS: Prostaglandin E2 increased contractility in chronically obstructed human ureters. In acutely obstructed porcine ureteral segments, low concentrations of PGE2 inhibited ureteral contractility in a dose-dependent fashion, similar to controls. At higher concentrations of PGE2, contractility was increased. This increase was more pronounced with longer intervals of obstruction in a time-dependent manner. CONCLUSION: Prostaglandin E2 increased contractility in obstructed ureters while relaxing normal and nonobstructed ureters. The response to PGE2 was accentuated by a longer duration of obstruction. Prostaglandin E2 may be a unique target for pharmacologic modulation in the treatment of symptoms associated with acute urinary obstruction.

Animals↗
PubMed2004

Clinical utility of dual active deflection flexible ureteroscope during upper tract ureteropyeloscopy.

OBJECTIVES: To evaluate the clinical utility of a dual active deflection ACMI DUR-8 Elite ureteroscope in a referral endourology practice. METHODS: Retrospective chart review was performed on 54 consecutive patients who underwent flexible ureteroscopy by a single surgeon (S.Y.N.) from February to July 2003. Cases in which standard flexible ureteroscopes alone could complete the procedure, cases in which standard flexible ureteroscopy could not complete the procedure and the DUR-8 Elite ureteroscope did, and cases in which both ureteroscopes failed to complete the procedure were analyzed. RESULTS: A total of 54 procedures were performed on 37 patients. Three cases were not analyzed because they were distal ureter procedures. Of the remaining 51 procedures, 6 were removed from analysis because they were second-look procedures. When classified by diagnosis, 27 patients had stones (79.4%), 5 had cancer (14.7%), and 1 had hematuria (2.9%). The global success rate was 91.1%. The average use rate of the DUR-8 was 28.9%, and the success rate using the DUR-8 Elite was 69.2% in those cases in which it was necessary. Of the 13 cases in which the DUR-8 was used, 61.5% were for lower pole pathologic findings. The DUR Elite use and success rate in the lower pole was 57.1% and 75%, respectively. A statistically significant association was found between the diagnosis and procedure location (P = 0.00128). CONCLUSIONS: Our preliminary data indicate that the dual deflecting DUR-8 Elite ureteroscope may be helpful in cases in which the single deflection flexible instruments fail to access and treat upper urinary tract pathologic findings.

Carcinoma, Transitional Cell↗
PubMed2004

Efficiency and cost of treating proximal ureteral stones: shock wave lithotripsy versus ureteroscopy plus holmium:yttrium-aluminum-garnet laser.

OBJECTIVES: To compare the success rates, cost effectiveness, and efficiency of ureteroscopy (URS) and extracorporeal shock wave lithotripsy (ESWL) for proximal ureteral stones. METHODS: In a retrospective manner, 220 patients who underwent treatment for proximal ureteral stones were included in the study. The patient records, radiographs, and billing statements of all patients treated for upper ureteral stones between January 1997 and June 2001 at Scott and White Memorial Hospital were reviewed. The patients were placed into two treatment groups according to the method of their stone's initial treatment. The stones were categorized as less than 1 cm and 1 cm or greater. RESULTS: A total of 111 patients were in the ESWL group, 73 of whom had stones less than 1 cm, and 109 patients in the URS group, 81 of whom had stones less than 1 cm. In the URS group, 91% were successfully treated with one treatment intervention, and 55% of the ESWL group were successfully treated with their initial intervention (P <0.0001). Of the patients with URS failure, all but one was treated successfully with a second URS. Of the patients with ESWL failure, 52% were treated successfully by subsequent URS. The remaining patients with ESWL failure were treated with repeat ESWL, with a 62% success rate. The efficiency quotient for stones less than 1 cm for URS and ESWL was 0.79 and 0.51, respectively. For stones 1 cm or greater, URS had an efficiency quotient of 0.72 and ESWL of 0.46. The URS group required fewer days to be stone free (8 versus 25.5 days, P <0.0001). No statistically significant difference was found in the overall complication rates (P = 0.43). URS had significantly lower charges for the initial procedure (7575 dollars versus 9507 dollars, P <0.0001). The total charges were also lower for URS (9378 dollars versus 15,583, dollars P <0.0001). Complications were similar in the two groups. The URS group had two ureteral strictures. CONCLUSIONS: The results of this study indicate that URS is more efficient and cost-effective for stones up to and larger than 1 cm with similar complication rates compared with ESWL.

Adult↗
PubMed2004

Hand-assisted laparoscopic radical nephrectomy.

Laparoscopic radical nephrectomy is the new standard of care for localized renal cancer. Hand assistance makes the procedure less daunting by providing tactile feedback. The authors consider the indications, contraindications, and technique for this operation, which provides the patient with the benefits of minimally invasive surgery while shortening the learning curve for the surgeon and allowing experienced laparoscopists to carry out more complex and challenging operations.

Equipment Design↗
PubMed2004

Hand-assisted laparoscopic renal surgery in the morbidly and profoundly obese.

BACKGROUND AND PURPOSE: Obesity has been regarded as a relative contraindication to standard laparoscopic procedures. We evaluated the impact of morbid (body mass index [BMI] >30 kg/m2) and profound (BMI > 40 kg/m2) obesity on the results of hand-assisted laparoscopic renal surgery (HALRS). PATIENTS AND METHODS: From September 1996 until October 2002, a total of 30 patients among 105 on whom HALRS was performed at our institution were morbidly obese, with a mean BMI of 35.8 kg/m2 (range 30.3-52.3 kg/m2). Eight patients were noted to have profound obesity, with a mean BMI of 44 kg/m2 (range 40.1-52.3 kg/m2). The HALRS procedures included radical nephrectomy in 23 patients, simple nephrectomy in 4, nephroureterectomy in 2, and partial nephrectomy in 1. At least one additional significant comorbidity was noted in 70% of these patients. We retrospectively evaluated the intraoperative and postoperative outcomes in this group of obese patients. RESULTS: All procedures were performed successfully without the need for open conversion. The mean operative time was 262 minutes (range 125-361 minutes), and the mean estimated blood loss was 217 mL (range 50-600 mL). No transfusions or intraoperative complications occurred. The mean hospital stay was 4.1 days (range 2-13 days). There were 7 minor postoperative complications including ileus (N = 5), wound cellulitis (1), and urinary retention (1). No complications occurred in the profoundly obese patient subgroup. CONCLUSIONS: Hand-assisted laparoscopic renal surgery is safe and effective in the morbidly and profoundly obese patient.

Adult↗
PubMed2003

University of Wisconsin experience using the Doli S lithotriptor.

OBJECTIVES: To present our initial results using the Dornier Doli S lithotriptor with the 220 electromagnetic shock wave emitter to treat urinary calculi. At present, there is no published report of the efficacy of this instrument in service in the United States. METHODS: We retrospectively reviewed the outcome of shock wave lithotripsy in 270 consecutive patients with solitary renal and/or ureteral stones treated from September 1998 to October 2001 with the Dornier Doli S lithotriptor. Data were collected with respect to stone size, location, and fragmentation. RESULTS: Of the 270 patients treated, 204 had renal stones and 66 had ureteral stones. All patients had solitary stones. The renal stones averaged 9.7 mm in size (range 4 to 26). The ureteral stones averaged 7.8 mm (range 4 to 17). Of the renal stones, 51% were located in the renal pelvis, with 18%, 5%, and 25% located in the upper, middle, and lower poles, respectively. Of the ureteral stones, 68% were located in the proximal ureter, with 14% and 18% in the mid and distal ureter, respectively. In the renal group, 176 (86%) of 204 patients achieved clinical success. Of these patients, 148 were stone free (73%) and 28 had residual fragments less than 4 mm in size (14%). In the ureteral group, 52 (79%) of 66 patients achieved clinical success. Of these patients, 50 were stone free (76%) and 2 (3%) patients had fragments less than 4 mm in size. Thirteen (6%) of 204 patients in the renal group required retreatment. Four (6%) of 62 patients in the ureteral group required retreatment. Of the patients in whom treatment failed and who had stone analysis, 16 (76%) of 21 had stones composed of predominantly calcium oxalate monohydrate. Four patients developed steinstrasse. Two were treated with retrograde stent placement, and the other two with placement of percutaneous nephrostomy. One patient developed a known perinephric hematoma but did not require a blood transfusion. CONCLUSIONS: Shock wave lithotripsy using the Doli S in appropriately selected patients is an effective instrument for treating urinary calculi throughout the urinary tract.

Calcium Oxalate↗
PubMed2003

Renal cryotherapy: 2003 clinical status.

PURPOSE OF REVIEW: Traditionally, curative therapy for most renal cancers involved open radical nephrectomy. However, as increased radiological monitoring has led to more incidentally discovered small renal masses, the optimal treatment has evolved. Nephron-sparing surgery, initially developed for patients with solitary kidneys or compromised renal function, emerged as the treatment of choice for small renal masses. It has been shown that long-term cancer control and renal function after partial nephrectomy equals the results of radical nephrectomy. Cryoablation of small renal masses represents an alternative method for performing nephron-sparing surgery. RECENT FINDINGS: Cryoablation of renal tumors with ultrasound monitoring may be performed under open exposure, but laparoscopy provides equivalent exposure with less morbidity. Cryotherapy may also be performed percutaneously with magnetic resonance image monitoring. After treatment, patients require diligent radiographic monitoring, more frequently than after surgical extirpation. SUMMARY: The durability of renal cryotherapy appears promising. More data are required to provide reliable treatment of tumor margins for larger lesions, and further to determine the safety of use near the collecting system and renal hilum. Currently, cryoablation of small renal lesions is minimally invasive, safe, and efficacious for select peripheral lesions in carefully selected patients.

Carcinoma, Renal Cell↗