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Biomedical subjects

Manoj Monga

Publications and source records attributed to Manoj Monga.

At least 37 records · Page 2Linked to original sources
PubMed2005

Radial dilation of ureteral balloons: comparative in vitro analysis.

BACKGROUND AND PURPOSE: The dynamics of ureteral balloon expansion may differ with increasing extrinsic compressive forces and inflation pressures. This study compared the ability of ureteral balloons to expand under different conditions. MATERIALS AND METHODS: The balloons tested were the Cook Accent, Ascend, Ascend AQ, and Pursuit; the Bard 195503 and UroForce; and the Boston Scientific Microvasive UroMax Ultra. When available, multiple balloon diameters and lengths were tested. With a guidewire in place, the balloon tip was secured by elevated vise grips on either side of the balloon. A string was wrapped around the balloon center once, and incremental increases in load were added (2 g, 42 g, 82 g, 122 g) to represent increasing extrinsic compression. The balloon was inflated with contrast medium, and circumference changes were measured at increments of 2 atm up to burst pressure. Balloons were tested in triplicate for each weight. RESULTS: The majority of the balloons were unable to reach 90% of their expected diameter with larger constrictive loads (122 g) at low inflation pressure (4 atm). The only balloons that achieved a diameter at 4 atm that was at least 90% of the expected diameter with a coefficient of variance (CV) of <10% at all radial loads were the Pursuit 6 mm x 4 cm (98.2 +/- 2.2%; CV 7.88%), UroMax Ultra 7 mm x 4 cm (97.5 +/- 1.4%; CV 5.94%), and the UroMax Ultra 7 mm x 6 cm (101 x 1.2%; CV 7.67%). At inflation burst pressure, the balloons able to maintain a diameter at or above 100% of expected with a CV of <5% at burst pressure were the Ascend AQ 4 mm x 4 cm (116 +/- 1.0%; CV 3.34%) and the Pursuit 6 mm x 4 cm (108 +/- 2.0%; CV 4.53%). CONCLUSION: Reaching maximum inflation diameter at low pressures in the face of increasing extrinsic compression may help minimize the risk of ureteral injury. Reliable expansion to maximum diameter even with higher extrinsic compressive forces is another important characteristic of ureteral balloons. Balloon material, configuration, and dimensions may contribute to differences in dilation properties.

Catheterization↗
PubMed2005

Impact of heads-up display imaging on endoscopic task performance.

BACKGROUND AND PURPOSE: Heads-Up Imaging goggles provide ergonomic advantages to the endourologist. This study was designed to evaluate whether heads-up display impacts task performance for ureteroscopic stone retrieval. MATERIALS AND METHODS: The ability to capture a 5-mm calculus with a Cook N-Circle 2.2F stone basket from an inanimate caliceal model was tested by three experienced and three novice stone-basket operators. Visual display for initial testing for each operator was randomized to the OptiVu HD3 Heads-Up googles or a 20- inch Sony Triniton monitor (TV). Subsequent testing alternated between the two devices. Camera input was provided by the Storz telecam SL-NTSC. The HD3 was set up to align the direction of view with the operator's hands, while the TV was aligned at an angle 45 degrees lateral and 30 degrees superior to the operator's direction of view to approximate the traditional room set-up for an endourologic procedure. Each operator performed five basketing trials with each display set-up. RESULTS: Expert operators retrieved calculi more rapidly (9.2 +/- 5.9 seconds) than novice operators (50.7 +/- 48.9 seconds), irrespective of whether a TV monitor or goggle display was utilized as the imaging modality. No significant differences were noted in task performance between the two imaging modalities for the expert (P = b0.60), novice (P = 0.77), or overall (P = 0.91) groups. CONCLUSION: The Optiview Heads-Up goggle display system does not offer advantages in task performance with specific regard to the ability to capture stone fragments with baskets.

Clinical Competence↗
PubMed2005

Randomized evaluation of Ureteral Stents using validated Symptom Questionnaire.

BACKGROUND AND PURPOSE: Ureteral stents are associated with significant pain and urinary symptoms. Manufacturers have altered stent designs and materials in an attempt to minimize this morbidity. This study evaluated the impact of these modifications. PATIENTS AND METHODS: Stent manufacturers were asked to provide the 6F ureteral stent they believed would be associated with the least patient discomfort. Patients undergoing uncomplicated ureteroscopy were randomized to the Bard Inlay, Cook Endo-Sof, Microvasive Contour, Applied Medical Vertex, or Surgitek Classic Double-Pigtail stent. The Ureteric Stent Symptom Questionnaire (USSQ) was administered on days 1, 3, and 5, and the patients maintained a narcotic diary. The data were analyzed using ANOVA and nonparametric methods. RESULTS: A total of 44 patients (73%) completed all USSQ questionnaires. Urinary symptom scores were significantly lower for the Inlay stent on day 3 than for the Vertex (P = 0.01), Contour (P = 0.05), Endo-Sof (P = 0.03), and Classic (P = 0.02) stents. No significant differences were noted in pain and general symptom scores or narcotic use. CONCLUSIONS: The Bard Inlay stent is associated with less-severe urinary symptoms than other ureteral stents. The USSQ is a sensitive tool to measure differences between stents.

Adult↗
PubMed2005

Temperature activated deflection of a novel ureteroscopic laser fiber sheath.

PURPOSE: Loss of active deflection with insertion of a holmium laser fiber can significantly decrease the efficacy of intrarenal flexible ureteroscopy. We evaluated the impact of inserting a novel, temperature activated, deflectable laser sheath on active deflection and flow rates. METHODS AND MATERIALS: Active deflection of 5 flexible ureteroscopes was measured with an empty channel and following separate insertions of 2, 272 mum holmium fibers. Insertion of the same fibers was then repeated through a proprietary, temperature activated, coiling nitinol sheath. Active deflection of the sheath following insertion into the working channel was achieved by a rapid flush of 10 cc hot water (60C) through the irrigation side port. Release of active deflection was obtained by repeating this maneuver with cold water (15C). Degrees of deflection were measured in triplicate. Flow rates were measured at 100 cm H2O pressure. RESULTS: Active deflection with an empty working channel decreased significantly with insertion of the 2 laser fibers (12 to 32 degrees). Insertion of the laser fiber through the nitinol sheath followed by temperature activation of the sheath maximized active deflection beyond baseline measures with the laser fibers by up to 60 degrees. Flow rates in all ureteroscopes decreased significantly with the use of the Powerflex sheath (Optical Integrity, Panama City, Florida) but it remained above 12 ml per minute in all ureteroscopes. CONCLUSIONS: A temperature activated, deflectable nitinol sheath facilitates active deflection with a 272 mum holmium laser fiber in the working channel of the flexible ureteroscope, suggesting strong potential for clinical evaluation.

Alloys↗
PubMed2005

Antibiotic prophylaxis for transurethral prostatic resection in men with preoperative urine containing less than 100,000 bacteria per ml: a systematic review.

PURPOSE: We determined whether antibiotic prophylaxis can reduce the risk of postoperative infective complications in men undergoing transurethral resection of the prostate (TURP) who have preoperative urine with less than 100,000 bacteria per ml. MATERIALS AND METHODS: MEDLINE, EMBASE (Elsevier B.V., Amsterdam, The Netherlands) and the Cochrane Library were searched for randomized and quasi-randomized controlled trials that compared the effects of antibiotic prophylaxis with placebo or active controls for men undergoing TURP with preoperative sterile urine. Two reviewers independently extracted patient characteristic and outcomes data based on a prospectively developed protocol. RESULTS: A total of 28 trials, 10 placebo controlled and 18 no treatment controlled, involving 4,694 patients, met the inclusion criteria. The mean age of the subjects was 69 years and the majority underwent TURP for prostatic hyperplasia (85%). Antibiotic prophylaxis was significantly more effective than placebo in reducing postoperative TURP complications. The risk differences for post-TURP bacteriuria, high degree fever, bacteremia and use of additional antibiotic treatment were -0.17 (95% CI 0.20, -0.15), -0.11 (-0.15, -0.06), -0.02 (-0.04, 0.00) and -0.20 (-0.28, -0.11), respectively. The results were observed consistently across all classes of antibiotics assessed. There was no difference in the duration of postoperative catheterization or hospitalization. Adverse events were rare, generally mild, and included allergic reactions, pyrexia and abdominal complaints. CONCLUSIONS: Prophylactic antibiotics decrease the incidence of post-TURP bacteriuria, high fever, bacteremia and additional antibiotic treatment. Additional research should evaluate the optimal antibiotic regimen, and whether the cost and possibility of the development of resistant strains of organisms justify the routine use of prophylactic antibiotics.

Aged↗
PubMed2005

Prospective, randomized trial comparing shock wave lithotripsy and ureteroscopy for lower pole caliceal calculi 1 cm or less.

PURPOSE: The optimal management of lower pole renal calculi is controversial. We compared shock wave lithotripsy (SWL) and ureteroscopy (URS) for the treatment of patients with small lower pole stones in a prospective, randomized, multicenter trial. MATERIALS AND METHODS: A total of 78 patients with 1 cm or less isolated lower pole stones were randomized to SWL or URS. The primary outcome measure was stone-free rate on noncontrast computerized tomography at 3 months. Secondary outcome parameters were length of stay, complication rates, need for secondary procedures and patient derived quality of life measures. RESULTS: A total of 67 patients randomized to SWL (32) or URS (35) completed treatment. The 2 groups were comparable with respect to age, sex, body mass index, side treated and stone surface area. Operative time was significantly shorter for SWL than URS (66 vs 90 minutes). At 3 months of followup 26 and 32 patients who underwent SWL and URS had radiographic followup that demonstrated a stone-free rate of 35% and 50%, respectively (p not significant). Intraoperative complications occurred in 1 SWL case (unable to target stone) and in 7 URS cases (failed access in 5 and perforation in 2), while postoperative complications occurred in 7 SWL and 7 URS cases. Patient derived quality of life measures favored SWL. CONCLUSIONS: This study failed to demonstrate a statistically significant difference in stone-free rates between SWL and URS for the treatment of small lower pole renal calculi. However, SWL was associated with greater patient acceptance and shorter convalescence.

Adult↗
PubMed2005

Laparoscopic ureterectomy for the management of painful calculi in a ureteral stump.

We present a rare case of a laparoscopic ureterectomy for the treatment of unusual chronic pain from a large retained stone in a ureteral stump. The history of long-term co morbidities from retained ureteral stumps is reviewed, as well as a discussion on the possible etiology of the pain for this particular patient. An argument for the change of the standard of care for the management of ureters in relation to nephrectomies is also made in regard to adult patients with a history of stone disease.

Chronic Disease↗
PubMed2005

Extracorporeal shock wave lithotripsy with a transportable electrohydraulic lithotripter: experience with >300 patients.

OBJECTIVE: To review a multicentre experience of using a transportable lithotripter (STS-T, Medstone, Inc, Aliso Viejo, CA. USA) for treating patients with urolithiasis in all parts of the urinary tract. PATIENTS AND METHODS: In all, 326 patients with a total of 370 stones were treated as outpatients with the STS-T lithotripter. All patients received a single shock wave lithotripsy treatment and were followed after 4-6 weeks in the outpatient clinic, the primary endpoint being to determine the efficacy (as defined by the stone-free rate). Secondary objectives included establishing a database of patient demographic information, stone characteristics, stone location, procedural endpoints, and complication rates. RESULTS: In all there were 370 procedures, with a mean of 2394 shocks administered at an energy level of 24 kV. The mean treatment time was 51 min, excluding anaesthesia-induction time. The mean stone aggregate size was 8.2 mm; 62% of the stones were in the kidney while 38% were in various locations in the ureter. Of the treated stones, 90% had definite or probable evidence of fragmentation. The overall stone-free rate after one treatment with the STS-T was 52.8%. Of patients with residual fragments, most (61%) had fragments of <4 mm in aggregate diameter. The overall complication rate was 3.8%, the most common complication being postoperative pain. CONCLUSION: The Medstone STS-T lithotripter was an effective device for treating urolithiasis in all parts of the urinary tract. This system had a high margin of safety, as shown by the low complication rate. With no apparent sacrifice of efficacy compared to first-generation or fixed (not transportable) second-generation devices, the Medstone STS-T represents an important advance in the development of a truly transportable lithotripter.

Adult↗
PubMed2004

Impact of infertility on quality of life, marital adjustment, and sexual function.

OBJECTIVES: To evaluate the hypothesis that infertility may result in a decrease in quality of life and an increase in marital discord and sexual dysfunction. The burden of infertility is physical, psychological, emotional, and financial. METHODS: Couples seeking treatment for infertility were asked to complete standardized validated questionnaires assessing quality of life (Quality of Well-Being Scale-Self Administered, version 1.04), marital adjustment (Locke-Wallace Marital Adjustment Test), and sexual function (Brief Index of Sexual Functioning for Women and International Index of Erectile Function for men). Couples seeking elective sterilization served as the control subjects. RESULTS: Eighteen infertile couples and 12 couples seeking elective sterilization participated in the study. The mean age, years together, and household income were comparable. Infertile couples had made a mean of 14.5 office visits for infertility, and 83% of couples reported feeling societal pressures to conceive. The Marital Adjustment Test scores for the women of the infertile couples were significantly lower than the scores of the controls (P = 0.01); however no difference was noted in the men. A trend toward lower quality-of-life scores was noted in women (P = 0.09) but not in the men of infertile couples. No statistically significant impact on sexual functioning in women was noted; however, the men in the infertile couples had lower total International Index of Erectile Function scores (P = 0.05) and intercourse satisfaction scores (P = 0.03). CONCLUSIONS: Women in infertile couples reported poor marital adjustment and quality of life compared with controls. Men may experience less intercourse satisfaction, perhaps because of the psychological pressure to try to conceive or because of the forced timing of intercourse around the woman's ovulatory cycle.

Adult↗
PubMed2004

Systematic evaluation of ureteral access sheaths.

OBJECTIVES: To compare the physical characteristics of ureteral access sheaths that affect their ability to resist buckling and kinking in the ureter. METHODS: Eight commercially available ureteral sheaths were tested. The buckling pressure was measured by adding sequential loads to a point 20 cm from the tip of the sheath until the mass that resulted in buckling of the catheter was determined. The kinking pressure was determined by measuring the diameter of the sheath with a digital caliper as sequential loads were applied to the surface of the sheath. The frictional properties of the sheath were measured by testing the force required to push the sheath through a mock tube. RESULTS: The Cook Flexor was more resistant to buckling, requiring 202 g of force before buckling occurred, and both the Cook Flexor and the Applied access sheaths were more lubricious. The kinking measurements demonstrated a linear loss of diameter of the sheath with added loads. The Applied Forte XE and Cook Flexor ureteral access sheaths were more resistant to kinking than were the other sheaths tested. CONCLUSIONS: Understanding the physical characteristics of ureteral sheaths may help determine which sheaths will perform well with regard to buckling during insertion and kinking during use.

Equipment Design↗
PubMed2004

Systematic evaluation of stone basket dimensions.

OBJECTIVES: To evaluate 17 commercial stone baskets for characteristics we believe are favorable for stone extraction. METHODS: The ACMI (Sur-Catch 3.0), Bard (Dimension 3.0), Boston Scientific (Zero-tip 2.4/3.0, Segura 2.4/3.0, Gemini 3.0, Parachute 3.1), Cook (N-Circle 2.2/3.0/3.2, N-Force 3.2, Flatwire 2.0), and Sacred Heart (Halo 1.9, Vantage 2.4, Summit 3.0, Hercules 3.0) were tested in triplicate. The maximal basket width was measured with a digital caliper as the basket length was opened in 0.5 to 2-mm increments using a mechanical caliper under optical light microscope visualization. Baskets were rated for the linearity of opening and length at which the target basket width (5 mm) was reached. RESULTS: The only basket to exhibit linear opening was the N-Circle. All other baskets opened in an exponential fashion, with the initial excursion in length corresponding to little change in basket width, followed by a rapid increase in basket width as the basket extended further. The N-Circle 2.2F, 3.0F, and 3.2F baskets reached the target basket width at a basket length of 9.4, 9.7, and 9.6 mm, respectively. As a group, the tipless baskets opened more rapidly to the target basket width (9.4 to 14.8 mm) than did the flat-wire baskets (17.5 to 22.7 mm) or helical baskets (18.6 to 24.8 mm). CONCLUSIONS: A basket that requires a shorter basket excursion to reach a 5-mm width will be easier to maintain in the field of view. Linear basket opening provides the operator with greater control to engage a stone. After closure of a basket on a 5-mm stone, the larger the basket length dimension, the greater the likelihood the calculus may escape.

Equipment Design↗
PubMed2004

Minimally invasive therapy for renal cell carcinoma: is there a new community standard?

OBJECTIVES: To evaluate current practice use of laparoscopic and minimally invasive therapies in the treatment of renal cell cancer. METHODS: A questionnaire was sent to 174 members of the Minnesota Urological Society. The first case scenario described a 6-cm lesion not amenable to nephron-sparing surgery. The second case scenario described a 3-cm lower pole exophytic mass amenable to nephron-sparing surgery. The treatment options included traditional therapy (open partial or radical nephrectomy) and minimally invasive therapy (laparoscopic radical or partial nephrectomy or renal cryoablation). RESULTS: Our survey response rate was 49%. For the first scenario, 86% of respondents would offer open radical nephrectomy; however, 57% would offer laparoscopic surgery. Of those urologists offering laparoscopic surgery, 14% would refer outside their practice and 43% would use a hand-assisted approach. Sixty-four percent of the metropolitan and 56% of the urban respondents would offer a form of minimally invasive therapy; only 29% of rural respondents offered these options. For the second scenario, 90% of respondents would offer open partial nephrectomy and 45% a minimally invasive therapy; however, 24% of these would refer outside their practice. Thirty-eight percent of respondents would offer laparoscopic partial nephrectomy and 22% of respondents would offer renal cryoablation. Urologists completing residency after 1990 were more likely to offer a minimally invasive option (65%) compared with urologists completing residency before 1990 (31%). CONCLUSIONS: Minimally invasive therapy for renal cell cancer is evolving into a community standard of care, with urologists relying heavily on outside referrals to access minimally invasive alternatives. Younger urologists living in metropolitan and urban areas are more likely to offer minimally invasive therapy. Additional emphasis should be placed on increasing the availability of minimally invasive techniques in rural settings.

Adult↗
PubMed2004

Is there a role for small-diameter ureteral access sheaths? Impact on irrigant flow and intrapelvic pressures.

OBJECTIVES: To evaluate irrigant flows and intrapelvic pressures with small-diameter access sheaths. Ureteral access sheaths improve irrigant flow and decrease intrarenal pelvic pressures during flexible ureteroscopy. However, no comparisons of individual sheaths have been conducted. Previous studies have demonstrated more favorable results with the 12F sheath than with the 10F sheath. METHODS: Ureteral access sheaths were tested ex vivo in porcine kidneys. An 18F angiocatheter was placed in the renal pelvis and connected to a Hewlett Packard Gauss Pressure transducer. Irrigant was maintained at 100 mm Hg pressure. Irrigant flow and intrapelvic pressures were measured with three flexible ureteroscopes at baseline and using each of four 10F sheaths, with the sheaths positioned in the middle ureter and the ureteroscopes positioned in the renal pelvis. The pressure at which irrigant efflux through the sheath occurred and the rate of irrigant efflux through the access sheath were measured. RESULTS: Intrapelvic pressures measured greater than 40 mm Hg, and irrigant flows remained at less than 15 mL/min when the Olympus URF-P3 and Storz 11274AAU flexible ureteroscopes were tested with all four sheaths. The intrapelvic pressures, irrigant inflow, and irrigant efflux with the Wolf 7325.172 (7.5F) flexible ureteroscope were optimized in combination with the Cook Peelaway 10F and Applied Access 10F sheaths. CONCLUSIONS: Small ureteral access sheaths should be used only with the Wolf 7325.172 flexible ureteroscope. The Cook Peelaway (10F) and Applied Access (10F) sheaths offered the greatest increase in irrigant flow and decrease in intrapelvic pressures.

Animals↗
PubMed2004

Comparison of tipless and helical baskets in an in vitro ureteral model.

OBJECTIVES: To compare the rapidity of stone capture and removal by six tipless and four helical baskets in a ureteral model. Expeditious ureteral stone extraction is reliant on the basket size, configuration, and radial dilation force. METHODS: A 5-mm feline calculus was placed in a simulated model of the human ureter at a distance of 7.5 cm from the orifice, and saline irrigant instilled. A 6/7.5F Wolf semirigid ureteroscope was used for access and visualization of the stone. Operators were randomized to start stone extraction with 1 of 10 stone baskets, and three extraction attempts were conducted with each device. Six experienced operators tested each device. The tipless baskets tested were the ACMI Sur-Catch NT 3.0F, Bard Dimension 3.0F, Boston Scientific Zerotip 3.0F, Cook N-Circle 3.0F, Cook Delta 2.4F, and Sacred Heart Halo 1.9F. The helical baskets tested were the Cook N-Force 3.2F, Microvasive Gemini 3.0F, ACMI Sur-Catch Helical 3.0F, and Sacred Heart Hercules 3.0F. The time to extraction in seconds was recorded. RESULTS: No statistically significant difference was observed between the tipless (14 +/- 7 seconds) or helical (12.8 +/- 6.6 seconds, P = 0.21) basket groups. All baskets were able to retrieve the ureteral stones successfully. The most efficient basket was the Cook N-Circle with an average time of 8.7 seconds to stone extraction compared with the least efficient basket, the ACMI Sur-Catch NT, at 15.8 seconds. CONCLUSIONS: The Cook N-Circle basket provided the most expeditious means to stone extraction in a ureteral model.

Animals↗
PubMed2004

A novel dual-diameter ureteroscope working channel: impact on irrigant flow.

OBJECTIVES: To compare irrigant flow characteristics through standard working channels (3.6F to 4.5F) and a dual-diameter working channel. Irrigant flow is critical for adequate visualization during endoscopic procedures. METHODS: Working channels were created out of 80 cm of light wall polytetrafluoroethylene (PTFE) tubing (inner diameter 3.6F, 4.0F, and 4.5F) with a male Luer connector attached to one end by epoxy resin. The dual-diameter working channel was created with a 70-cm segment of PTFE (4.5F inner diameter, 0.059 in.) and a 10-cm segment of PTFE (3.6F inner diameter, 0.047 in.) with a male Luer connector attached to the free end of the 4.5F tubing. Stone basket shafts (100 cm in length, outer diameter 1.9F, 2.4F, and 3.0F) were created out of unmodified polyimide tubing with a 0.018-in.-diameter nitinol mandrel epoxy core for stability. Irrigant flow was measured at 100 mm Hg pressure for 1 minute with an empty channel and with stone basket shafts in the channel. RESULTS: The flow rates were significantly greater with the dual-diameter working channel than with the standard flexible ureteroscope (3.6F) working channel using an empty channel (79.2 versus 44.1 mL/min, P = 0.0001), 1.9F basket (35.9 versus 10.0 mL/min, P = 0.003), 2.4F basket (20.7 versus 4.3 mL/min, P = 0.002), and 3.0F basket (6.0 versus 0.7 mL/min, P = 0.0002) sheath. CONCLUSIONS: A dual-diameter working channel may optimize irrigant flow characteristics for flexible ureteroscopes while maintaining a small distal tip diameter.

Polytetrafluoroethylene↗
PubMed2004

Advanced intrarenal ureteroscopic procedures.

The role of flexible ureteroscopy in the management of intrarenal pathology has undergone a dramatic evolution, powered by improvements in flexible ureteroscope design; deflection and image quality; diversification of small, disposable instrumentation; and the use of holmium laser lithotripsy. This article reviews the application of flexible ureteroscopy for advanced intrarenal procedures.

Clinical Trials as Topic↗