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Biomedical subjects

L Le Normand

Publications and source records attributed to L Le Normand.

At least 19 recordsLinked to original sources
PubMed2005

[Upper urinary tract: physiology, pathophysiology of obstructions and function assessment].

The urine is transported from the renal papilla to the bladder through the upper urinary tract which allows this transport to be safe and comfortable, i.e., without any risk or pain for the kidney. This active transport depends on the smooth muscle contractile properties. The upper urinary tract is totally autonomous; this feature allows the preservation of its function after renal transplantation. However, despite its accessory role, the autonomous nervous system can modulate its activity. Upper urinary tract obstruction involves adaptative mechanisms which are different depending on the type (acute, chronic, acquired or congenital) of obstruction. Functional evaluations of the upper urinary tract are aimed at identify the urine transport conditions and the relationship between obstruction and clinical conditions such as hydronephrosis, pain or impaired renal function.

Humans↗
PubMed2004

[Augmentation enterocystoplasty].

Augmentation enterocystoplasty refers to a technique that consists in removing a bowel segment in order to suture it onto the bladder. This technique is indicated in case of reduced bladder capacity and/or compliance, in case of failure of conservative treatments. The goal is to improve the patient's urination comfort, but above all to ensure long-term protection of the upper urinary tract. All bowel segments may be utilized but the ileum is the segment of choice. The selected digestive segment must be detubulized in order to better decrease its peristaltic contractions and obtain low-pressure urine storage. Bi-valving the bladder while preserving the detrusor usually performs augmentation enterocystoplasty. However, in case of very fibrous and thickened detrusor, a supra-trigonal cystectomy should be considered. The digestive segment is removed and detubulized, then it is sutured on to the bladder as a patch at the incision level. Following such surgery, over 90% of the patients report significantly improved quality of life. Nocturnal bladder competence is obtained in more than 90% of the patients, while 91 to 100% report diurnal bladder competence. Long-term complications may be observed, such as chronic infections with asymptomatic bacteruria (70% of the cases) not necessitating any treatment. Within the two first years, there is a 10% to 15% risk for stone formation following intestinal mucus development. Enterocystoplasty perforation may occur at a frequency estimated to range from 5 to 13%, which is a very serious and life-threatening complication. Similarly, a risk of enterocystoplasty cancer may be observed after five to ten years, in 1% of the cases.

Cystectomy↗
PubMed2003

Clinical and urodynamic repercussions after TVT procedure and how to diminish patient complaints.

OBJECTIVES: Analysis of changes in voiding patterns after sub-urethral TVT procedure: urodynamic variations and clinical repercussions. METHODS: 112 women included in an ethics committee protocol (CCPPRB ) with a mean follow-up of 22 months underwent complete urodynamic testing before and after TVT procedure and filled in pre- and post-operative questionnaires. RESULTS: Analysis of the questionnaires showed that two clinical symptoms were predominant post-operatively: dysuria and micturitional urge. The urodynamic profiles showed that TVT banding led to infravesical obstruction but not to significant detrusor overactivity. CONCLUSION: Our results show that clinical changes induced by the TVT procedure were due to infravesical obstruction, and that there was no progression of detrusor overactivity. We suggest two ways to avoid, or diminish, this post-operative obstruction, or to detect patients at risk from obstruction: training for women who use their abdominal muscles for voiding rather than their detrusor, or pre-operative screening of hypotonic bladders.

Adult↗
PubMed2001

[Accuracy of pressure measurements obtained with a new rectal balloon catheter].

UNLABELLED: The accuracy of measurements performed by a balloon catheter used to record abdominal pressure during urodynamic investigations was verified on a test bench. OBJECTIVE: To study the accuracy and precision of the pressure measurements obtained with a new rectal balloon catheter (ref. 95018 Laboratoires Vermed), designed to record abdominal pressure during urodynamic assessments. The clinical value of this catheter, using air for pressure transmission, is its simplicity, as there is no contamination of the perfusion circuit or transducer, no purging of the circuit, and artefacts related to movements of the tubing are eliminated. METHOD: The catheter was placed in a pressure chamber fitted with a precise, calibrated regulation system allowing programmed pressure variations from 10 to 150 cmH2O. Pressures recorded by the test catheter were compared to reference pressures applied to the chamber. The frequency of acquisition of pressure measurements was 100 Hertz and the resolution was 10 Hertz. This model was used to study the accuracy of pressure measurements and the response times of the catheter. Measurements were performed with a volume of 2 ml of air introduced into the catheter (volume recommended by the manufacturer), and the optimal volume was investigated by inflating the catheter until the best result was obtained. The evaluation was based on calculation of the mean difference observed between the two measurements and the scatter of the differences observed. RESULTS: When the catheter was filled with 2 ml of air, pressures measured by the catheter were overestimated an average of 1.1 cmH2O (standard deviation = 1), and 95% of the differences between the two measurements were within +/- 2.15 cmH2O. The optimal air volume was found to be 1.5 ml. With this air volume, no significant difference was observed between the two measurements. The mean observed difference was 0.2 cmH2O (SD = 1.2), which means that 95% of the differences were situated within the range of +/- 2.35 cmH2O. CONCLUSION: The pressure recording method with this new catheter is validated in terms of physical parameters.

Equipment Design↗
PubMed1999

[Several difficult diagnoses of dysuria in patients with prostatic adenoma: value of urodynamic studies].

UNLABELLED: The objective of these clinical case reports is to illustrate the value of urodynamic studies in the therapeutic decision for patients with benign prostatic hyperplasia, but whose vesico-sphincteric equilibrium may also be modified by other concomitant diseases. Three cases illustrate comparable clinical situations, but with very different vesico-sphincteric behaviour. Urodynamic studies are able to globally characterize the patient's vesico-sphincteric behaviour. Unlike clinical assessment alone, the results of urodynamic studies guide the choice of treatment, designed to modify this equilibrium in the desired direction. CONCLUSION: Before proposing desobstruction surgery in dysuric patients with benign prostatic hyperplasia, as well as concomitant disease likely to modify his vesico-sphincteric behaviour, urodynamic studies are very useful, as they can modify the therapeutic decision.

Aged↗
PubMed1998

Randomized comparison of triple therapy and antithymocyte globulin induction treatment after simultaneous pancreas-kidney transplantation.

BACKGROUND: The incidence of acute rejection is considered to be higher after simultaneous pancreas-kidney (SPK) transplantation as compared to renal transplant alone. Therefore, the majority of SPK transplant recipients commonly receive a combination of cyclosporine (CsA) or tracolimus, and azathioprine or mycophenolic mofetyl, corticosteroids and/or antilymphocyte preparations. This study was designed to compare two immunosuppressive protocols for the prevention of acute rejection in patients undergoing SPK transplantation. The primary end-point was the incidence of acute rejection during the first 12 months after transplantation METHODS: Fifty patients with type-I insulin-dependent diabetes and chronic renal failure were randomized to receive a triple drug immunosuppressive regimen including CsA, azathioprine and corticosteroids (N = 25), or the quadruple sequential combination of rabbit antithymocyte globulin (ATG) given for 10 days, azathioprine, corticosteroids and delayed CsA (N = 25). Maintenance immunosuppression (CsA and azathioprine, without corticosteroids) was similar in both arms. RESULTS: The average follow-up was 36 months in both groups (range 9 to 60 months). No patient was excluded from the study. Although the percentage of patients with adverse events was higher in the ATG group (80 vs. 40%, P < 0.01), none of them resulted in premature discontinuation of the drug. Patients receiving ATG experienced a lower incidence (36% vs. 76%, P < 0.01) and number (13 vs. 29, P < 0.05) of acute renal rejection episodes. However, no difference was observed in patient, pancreas and kidney survival rates between groups. No case of isolated pancreas rejection was observed. CONCLUSIONS: The quadruple sequential combination ATG, azathioprine, corticosteroid and CsA significantly reduced the one year incidence of acute renal rejection after SPK transplantation, compared to a triple immunosuppressive regimen.

Adrenal Cortex Hormones↗
PubMed1998

The urodynamic effects of intravenous opioids and ketoprofen in humans.

UNLABELLED: We used a double-blind design to study urodynamic changes induced by mu-agonists (fentanyl, morphine), a partial mu-agonist antagonist (buprenorphine), a putative mu-antagonist, kappa-agonist (nalbuphine), and ketoprofen, an injectable nonsteroidal antiinflammatory drug. Men (20-55 yr old) were randomly assigned to receive one of the following i.v. before anesthesia for endoscopic extraction of a ureteral stone: 10 mg of morphine, 0.3 mg of buprenorphine, 0.35 mg of fentanyl, 20 mg of nalbuphine, 100 mg of ketoprofen, or 10 mL of 0.9% sodium chloride. The urodynamic study consisted of cystometry followed by urethral pressure profile. Measurements were taken before the i.v. infusion of drugs and 15 min thereafter. Statistical comparisons were performed by using analysis of variance with repeated measurements (P < 0.05). Ketoprofen and saline did not induce any urodynamic changes. Opioids altered bladder sensations, and the residual volume after voiding increased, except after morphine. Detrusor contraction decreased only after the administration of fentanyl and buprenorphine. Some patients could not micturate after receiving morphine, fentanyl, and buprenorphine. Compliance and urethral pressures did not change with any drug. This study suggests that ketoprofen and nalbuphine are useful analgesics in terms of their urodynamics. IMPLICATIONS: We compared the urodynamic effects of opioids and ketoprofen used as analgesics in surgical patients. In contrast to ketoprofen, opioids altered urodynamics. The opioid nalbuphine had no effect on detrusor contraction. This study suggests that ketoprofen and nalbuphine are useful analgesics in terms of their urodynamics.

Adult↗
PubMed1997

[Outcome of nephrogenic metaplasia of the bladder in kidney transplant recipients].

OBJECTIVES: To evaluate the risk of recurrence and malignant degeneration of vesical nephrogenic metaplasia in renal transplant recipients. MATERIAL AND METHODS: Fourteen patients with known nephrogenic metaplasia were systematically followed. Vesical biopsies were performed with a resector, stained with eosin haemalun saffron, analysed and compared to initial results. Labelling by anti-EBV and anti-CMV monoclonal antibodies was performed in 5 cases of intense inflammatory reactions. RESULTS: All patients were males, with a median age of 39 years. Nephrogenic metaplasia had been diagnosed 7 to 80 months after renal transplantation (median = 37.8). Twelve patients were reviewed 5 to 116 months after the initial diagnosis (median = 52). Relapse was observed in 83% of cases, but without any malignant degeneration. CONCLUSION: Nephrogenic metaplasia is therefore a benign recurrent disease. The importance of the initial blood supply and fibrosis in the case of recurrence suggest a disorder of the blood supply, probably traumatic in origin. Only symptomatic patients are currently followed.

Adolescent↗
PubMed1996

[Instantaneous pressure/flow ratio for non-permanent flows. Impact on the assessment of urethral resistance].

OBJECTIVE: To verify the validity of the hypothesis of the almost continuous flow necessary for evaluation of instantaneous urethral resistance R by the pressure/flow relation R = P/Q2. METHOD: An experimental device allowed investigation of the pressure/flow relation for discontinuous flow in a flexible tube. The tube was submitted to various collapsing pressures and opened under the effect of flow. The flow was discontinuous because of the variations of the proximal pressure or oscillations in the hydraulic diameter of the tube. RESULTS: These experiments showed that the approximation of continuous flow is justified within the limits of precision of the measuring methods used in urodynamics. CONCLUSION: The formula R = Q2 is therefore theoretically correct and validated by the experimentation. There is no hydrodynamic obstacle to the application of this formula to the calculation of instantaneous urethral resistance.

Pressure↗
PubMed1995

[Reliability of pressure measures determined with probes used for establishing the urethral pressure profile by the perfusion method].

The objective of this study was to evaluate the reliability of pressure measurements by the main catheters used to determine urethral profiles by the perfusion method. This evaluation, performed on a test bench, compared the reference pressure in a tank filled with water to that measured by the catheter tested. The reliability of the measurement varied from one catheter to another. This disparity was due to differences of load losses, leading to an overestimation of the measurement (by 2 to 17 centimetres of water), which must be corrected by adjustment of the zero pressure with a perfused catheter. Major differences in the rapidity of response (from zero to five seconds) were also observed, which appear to be related to elastic properties of the catheter. This study does not pretend to globally verify the reliability of the perfusion method, but only the reliability of pressure measurements.

Perfusion↗
PubMed1993

Nonsurgical treatment evaluation in benign prostatic hyperplasia patients.

The development of new methods for treating benign prostatic hyperplasia (BPH) requires the choice of reliable criteria in order to assess their efficiency. It is, first of all, necessary to choose clinical as well as urodynamic criteria. Clinical criteria must be quantified and then gathered in scores, so that they can be compared. These changes, essential to the statistician, alter the true meaning of symptoms. The value of urodynamic parameters to 'measure' obstruction differs widely: the pressure/flow relationship as well as micturitional bladder pressure are probably the most reliable. Statistical data processing for both qualitative and quantitative variables, is still likely to alter the true meaning of these variables. This article takes a critical approach to all these problems, and also focuses on the real aim of the BPH treatment, which above all is to restore comfortable functional balance but not necessarily urodynamic performance.

Clinical Protocols↗
PubMed1993

[Incidence of the form and caliber of urethral resistance. Evaluation for a normal masculine urethra and in cases of obstruction due to prostatic hypertrophy].

Certain forms of benign prostatic hypertrophy are associated with a reduction of the calibre of the prostatic urethra of the median lobe, a defect of infundibulisation of the bladder neck and a dilated appearance of the bulbar urethra. The objective of this study was to verify whether hydrodynamic arguments could be used to confirm the concept that defective infundibulisation of the bladder neck is directly responsible for an obstructive syndrome or via a reduction in the calibre of the bladder neck orifice. More generally, this study was designed to quantify the distribution of resistance to flow along the normal urethra and to define the role of cervicoprostatic and urethral deformities in the obstruction associated with benign prostatic hypertrophy. Urodynamic studies are unable to answer this question, as the instantaneous urethral resistance is evaluated globally by the Pressure-Flow relation. The authors performed morphological analysis to divide the urethra into simple hydraulic segments for which the corresponding pressure drop coefficients were calculated. These coefficients constitute an approach to segmental resistance to flow and can be used to quantify changes in shape observed on voiding urethrography or ultrasonography. Digital analysis of voiding urethrographies showed that, under normal conditions, urethral resistance was regularly distributed along the urethra and essentially depended on friction of the urethral wall. In the case of benign prostatic hypertrophy, even with a median lobe, the increase in the pressure drop coefficients was due to a reduction in the calibre of the bladder neck orifice and prostatic urethra. Cervical deformities appeared to be minimally obstructive, according to urodynamic parameters, if they were not associated with a reduction in the calibre of the bladder neck orifice.

Evaluation Studies as Topic↗
PubMed1993

[Autosomal dominant polycystic kidney disease: urologic complications and results of kidney transplantation: 217 patients].

The authors report a retrospective series of 217 cases of autosomal dominant renal polycystic disease collected over a period of 30 years in the urology and nephrology departments of Nantes university hospital. They study the incidence of urological complications, observed in 87 patients (40%), consisting of calculi (15%), infection (22%, with 4 deaths), intracystic haemorrhages (3.5%) and urinary tract compression (2%). The diagnostic and therapeutic methods are presented and discussed. The results of renal transplantation are also analysed: 39 patients were transplanted, 72% retained a functioning kidney with a mean follow-up of 44.9 months (range: 12-108 months) and three patients died as a result of infectious complications. The 1-year and 3-year actuarial transplant survival rate of 92% was similar to that of renal transplantations performed for another form of renal disease. Preparation for renal transplantation remains an essential problem: the two major indications for pre-transplantation nephrectomy were the size of the kidneys and the presence of infection.

Adolescent↗
PubMed1991

Vesicoureteral reflux in the renal transplantation candidate.

The incidence and severity of urinary tract infection episodes were evaluated in two groups of renal transplantation patients. Group 1 consisted of 11 patients transplanted following successful surgical correction of a noninfected vesicoureteral reflux in native kidneys, and group 2 of 28 patients transplanted with a noninfected vesicoureteral reflux. An increased incidence of acute urinary tract infection episodes was noted in group 2 as compared to group 1 (42.8 vs. 18%), with a mean of 2.6 +/- 1.4 episodes per patient in group 2 and 0.5 +/- 0.32 in group 1. Asymptomatic bacteriuria was not statistically different in the two groups (36.4 vs. 25%). In group 2, the incidence of urinary tract infection episodes increased in patients presenting high-grade (3 and 4) reflux in native kidneys. Despite the relatively low number of patients involved, our observations indicate that high-grade vesicoureteral reflux in native kidneys must be operated before transplantation, even when there is no history of urinary tract infections and urine cultures are sterile.

Acute Disease↗
PubMed1990

[Urodynamic consequences of urethral stenosis. Hydrodynamic study with a theoretical model].

An urethral model was designed to assess the hydrodynamic consequences of stenosis of the bulbar urethra. This model was based on the geometric and hydrodynamic analysis of micturing urethrograms in a patient whose maximum flow rate was 24 ml/s for a bladder pressure of 40 cm of water. It corresponds to the conditions of flow observed wit maximum bladder pressure and flow rate. During this short period, the shape of the urethra is regarded as stable. Calculation took account of the characteristics of a turbulent flow of urine, of the head loss due to friction of the urine on the walls and of the head loss caused by the geometrical changes of the urethra from the neck of the bladder to the meatus. In these conditions, applying Bernouilli's equation allowed plotting of bladder pressure for various levels of urethral resistance. If there is no stenosis, the theoretical maximum flow rate of the model with a bladder pressure of 40 to 80 cm of water should be 19 to 26 ml/s. Calculation showed that a sudden reduction of the diameter to less than 2.5 mm occurring in a segment of the urethra with a diameter of 4 mm accounts for a flox rate lower than 15 ml/s, except when bladder pressure can exceed 100 cm of water. The decrease in the maximum flow rate caused by urethral stenosis is all the greater as bladder pressure remains low or normal, with other causes of head loss or with associated upstream dilatation. Lastly, progressive narrowing leads to a smaller head loss and will therefore be better tolerated than sudden narrowing to the same caliber. Inversely, a long stenosis will be less well tolerated as the head loss due to friction in a long and narrow passage is increased. The diameter of a stenosis accounting for a maximum flow rate of less than 15 ml/s cannot be determined in the absolute. Analyzing the hydrodynamic consequences of stenosis also requires knowing the associated urodynamic and geometric parameters.

Adult↗
PubMed1989

[The Whitaker test. Its reliability and place in the study of congenital malformative uropathies].

47 children with hydronephrosis or megaureter under went urodynamic assessment by Whitaker's test. The reliability of this test, evaluated on a long-term follow-up (3.20 years in average) by clinical, radiographic and diuretic renogram test, was excellent in 86.6 per cent. This reliability was better in hydronephrosis (90.5%) than in megaureter (83.3%). The comparison between diuretic renogram and Whitaker's test showed a discordance in 43 per cent. But the diuretic renogram was still a good urodynamic assessment when the curve was not equivocal. In others cases, Whitaker's test was essential for the diagnosis of obstruction.

Adolescent↗