[The medical devices vigilance system].
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Equipment and Supplies↗
Biomedical subjects
Pierre Conort
Publications and source records attributed to Pierre Conort.
Helical CT evaluation of the chemical composition of urinary tract calculi with a discriminant analysis of CT-attenuation values and density.
The aim of this study was to evaluate the efficacy of helical CT using a combination of CT-attenuation values and visual assessment of stone density as well as discriminant linear analysis to predict the chemical composition of urinary calculi. One hundred human urinary calculi were obtained from a stone-analysis laboratory and placed in 20 excised pig kidneys. They were scanned at 80, 120 and 140 kV with 3-mm collimation. Average, highest and lowest CT-attenuation values and CT variability were recorded. The internal calculus structure was assessed using a wide window setting, and visual assessment of stone density was recorded. A stepwise discriminant linear analysis was performed. The following three variables were discriminant: highest CT-attenuation value, visual density, and highest CT-attenuation value/area ratio, all at 80 kV. The probability of correctly classifying stone composition with these three variables was 0.64, ranging from 0.54 for mixed calculi to 0.69 for pure calculi. The probabilities of correctly classifying calculus composition were: 0.91 for calcium oxalate monohydrate and brushite, 0.89 for cystine, 0.85 for uric acid, 0.11 for calcium oxalate dihydrate, 0.10 for hydroxyapatite, and 0.07 for struvite calculi. When the first two ranks of highest probability for the accurate classification of each calculus type were taken into account, 81% of the calculi were correctly classified. Assessment at 80 kV of the highest CT-attenuation value, visual density and the highest CT-attenuation value/area ratio accurately predicts the chemical composition of 64-81% of urinary calculi. When the first two ranks of highest probability for the accurate classification of each calculus type were taken into account, all cystine, calcium oxalate monohydrate and brushite calculi were correctly classified.
Animals↗
[Guidelines for the urological management of renal and ureteric stones in adults].
Progress in the treatment of urinary stones over the last 20 years requires a clearer definition of the indications for each treatment modality for the urological management of renal and ureteric stones in adults. The Stones Committee of the Association Française d'Urologie reviewed the European and American guidelines, the literature published over the last five years, and the experience of its members to establish a set of practical guidelines for the treatment of urinary stones. The site (kidney or ureter) and size (dimensions) of the stone are the initial descriptive criteria for the choice of treatment. Indications are classified as "standard" for first-line treatments, or "optional" for alternative modalities. The success of treatment is defined by the absence of residual fragments. ESWL is the reference treatment for renal stones less than 20 mm in diameter. PCNL is the most effective treatment for stones larger than 20 mm. Flexible ureteroscopy is still under evaluation. Open surgery and laparoscopy have limited indications in less than 1% of cases. ESWL is the first-line treatment for proximal ureteric stones. ESWL and ureteroscopy are both treatments of choice for stones of the pelvic ureter less than 10 mm in diameter, while ureteroscopy is recommended for stones larger than 10 mm. Stone morphology and composition analysis and an aetiological survey must be performed after surgical treatment and the patient must be given dietary advice to prevent recurrence.
Adult↗
[Percutaneous nephrolithotomy (PCNL) in subjects over the age of 70: a multicentre retrospective study of 210 cases].
INTRODUCTION: Percutaneous nephrolithotomy (PCNL) in subjects over the age of 70 is considered to be associated with a higher risk than extracorporeal shock-wave lithotripsy (ESWL). However this technique is sometimes necessary for very large or complex stones in patients with several comorbidities. STUDY OBJECTIVE: To evaluate the predictive factors of success and operative risks likely to influence the results of PCNL in a population of patients over the age of 70. MATERIAL AND METHOD: Retrospective study of 203 patients (110 males, 97 females) over the age of 70, in whom a total of 210 PCNL were performed over a 12-year period in ten referral centres for the treatment of stones. 68.5% of cases presented a comorbidity and the median ASA score was 2. The median stone dimensions were 24 x 15 mm. There were 67 solitary pelvic stones, 7 infrapelvic ureteric stones, 31 solitary inferior caliceal stones, 40 complex stones and 13 staghorn calculi. A standard one-stage operative technique was performed in 92% of cases; the nephrostomy tract was easily performed by the urologists themselves in 71.8% of cases. RESULTS: The overall stone-free (SF) rate was 70.8%. The patient's weight and height (p=0.03 and p=0.01), stone dimensions and their solitary nature were significant factors of success (p<0.00001 and p=0.01) with SF rates of 81.1% for pelvic stones and 90.3%for solitary inferior caliceal stones (p<0.003); the SF rate for complete staghorn calculi was only 30.8%. A history of stones (p=0.04) and diabetes (p=0.03) influenced the stone-free rate, but the other comorbidities, body mass index, and age did not influence the stone-free rate. There were two deaths (0.9% and haemostasis nephrectomy was performed in 2 ASA 3 subjects in renal failure. In the other patients, there was no difference between preoperative and postoperative serum creatinine and haemoglobin levels. The ease of nephrostomy, the rapidity of PCNL, the day of removal of the drainage nephrostomy, the mean hospital stay (median stay: 6 days), sterility of postoperative urine and at the 1-month visit were significantly correlated with the SF rate. CONCLUSIONS: PCNL in subjects over the age of 70 years is a safe and reliable technique that achieved a stone-free rate of 70.8% for all types of stones combined. The best results were obtained for solitary stones larger than 20 mm in the renal pelvis or inferior calyx. Apart from diabetes, which remains a risk factor, well controlled comorbidities do not increase the operative risk. PCNL did not affect haemodynamic parameters or renal function.
Age Factors↗
[Urinary stones in subjects over the age of sixty].
OBJECTIVE: Urinary stones, affecting 10% of the French population, is a frequent disease. Data of the literature on this disease in subjects over the age of 60 years reveal age-related changes of risk factors, especially affecting urine composition, but very few data have been reported concerning the clinical characteristics of the disease. Due to the absence of recent data on urinary stones in subjects over the age of 60 in France, we decided to study the epidemiology and urological treatment of urinary stones in the elderly in France. MATERIAL AND METHOD: From November 2001 to August 2002, a survey concerning urinary stones in subjects over the age of 60 was performed by the Association Française d'Urologie Stone Committee among urologist members of the AFU. The parameters studied were epidemiological, clinical, metabolic and therapeutic. The results were analysed on the overall patient population and on the subgroup of patients over the age of 70. RESULTS: The study included 176 patients over the age of 60, 110 of whom were over the age of 70. These patients presented their first episode of urinary stones in 41% of cases. Renal colic was the most frequent presenting symptom. Signs of severity were frequently associated, with urinary tract infection in 24% of cases, associated with sepsis in 49% of cases after the age of 70 years. The incidence of uric acid stones was higher than in the general population. CONCLUSION: Urinary stones can often occur for the first time after the age of 60. This disease appears to be more serious than in the general population due to the high incidence of infectious complications. Uric stones also appear to be more frequent. A multidisciplinary study based on a larger population is necessary to confirm these results.
Age Distribution↗
Pinball calculus in a ureterosigmoidostomy.
We report a complication during the treatment of lithiasis with extracorporeal shock wave lithotripsy in a patient with a ureterosigmoidostomy. This woman presented with renal colic bilaterally and renal insufficiency and was found to have an extremely mobile calculus. A significant gaseous reflux from the sigmoid colon was found to propel the solitary calculus in a retrograde fashion across the ureteroileal anastomosis up the ureter into one kidney, and then later, after re-descent to the level of the anastomosis, up into the opposite kidney. After several days of playing hide and seek with this migrating calculus, using extracorporeal shock wave lithotripsy, the patient became stone free.
Adult↗