Imaging-based assessment of the mineral composition of urinary stones: an in vitro study of the combination of hounsfield unit measurement in noncontrast helical computerized tomography and the twinkling artifact in color Doppler ultrasound.

We evaluated the value of combining noncontrast helical computerized tomography (NCHCT) and color Doppler ultrasound in the assessment of the composition of urinary stones. In vitro, we studied 120 stones of known composition, that separate into the five main types: 18 calcium oxalate monohydrate (COM) stones, 41 calcium oxalate dihydrate (COD) stones, 24 uric acid stones, 25 calcium phosphate stones and 12 cystine calculi. Stones were characterized in terms of their Hounsfield density (HU) in NCHCT and the presence of a twinkling artifact (TA) in color Doppler ultrasound. There were statistically significant HU differences between calcium and non-calcium stones (p < 0.001), calcium oxalate stones and calcium phosphate stones (p < 0.001) and uric acid stones and cystine calculi (p < 0.001) but not between COM and COD stones (p = 0.786). Hence, the HU was a predictive factor of the composition of all types of stones, other than for COM and COD stones within the calcium oxalate class (p > 0.05). We found that the TA does not enable differentiation between calcium and non-calcium stones (p > 0.999), calcium oxalate stones and calcium phosphate stones (p = 0.15), or uric acid stones and cystine calculi (p = 0.079). However, it did reveal a significant difference between COM and COD stones (p = 0.002). The absence of a TA is a predictive factor for the presence of COM stones (p = 0.008). Hence, the association of NCHCT and Doppler enables the accurate classification of the five types of stones in vitro.

Positive surgical margin appears to have negligible impact on survival of renal cell carcinomas treated by nephron-sparing surgery.

BACKGROUND: The occurrence of positive surgical margins (PSMs) after partial nephrectomy (PN) is rare, and little is known about their natural history. OBJECTIVE: To identify predictive factors of cancer recurrence and related death in patients having a PSM following PN. DESIGN, SETTING, AND PARTICIPANTS: Some 111 patients with a PSM were identified from a multicentre retrospective survey and were compared with 664 negative surgical margin (NSM) patients. A second cohort of NSM patients was created by matching NSM to PSM for indication, tumour size, and tumour grade. MEASUREMENTS: PSM and NSM patients were compared using student t tests and chi-square tests on independent samples. A Cox proportional hazards regression model was used to test the independent effects of clinical and pathologic variables on survival. RESULTS AND LIMITATIONS: Mean age at diagnosis was 61+/-12.5 yr. Mean tumour size was 3.5+/-2 cm. Imperative indications accounted for 39% (43 of 111) of the cases. Some 18 patients (16%) underwent a second surgery (partial or total nephrectomy). With a mean follow-up of 37 mo, 11 patients (10%) had recurrences and 12 patients (11%) died, including 6 patients (5.4%) who died of cancer progression. Some 91% (10 of 11) of the patients who had recurrences and 83% of the patients (10 of 12) who died belonged to the group with imperative surgical indications. Rates of recurrence-free survival, of cancer-specific survival, and of overall survival were the same among NSM patients and PSM patients. The multivariable Cox model showed that the two variables that could predict recurrence were the indication (p=0.017) and tumour location (p=0.02). No other variable, including PSM status, had any effect on recurrence. None of the studied parameters had any effect on the rate of cancer-specific survival. CONCLUSIONS: PSM status occurs more frequently in cases in which surgery is imperative and is associated with an increased risk of recurrence, but PSM status does not appear to influence cancer-specific survival. Additional follow-up is needed.

Tubeless percutaneous nephrolithotomy: what about replacing the Double-J stent with a ureteral catheter?

PURPOSE: To evaluate the feasibility and safety of replacing the Double-J stent with a ureteral catheter in tubeless percutaneous nephrolithotomy (PCNL). MATERIALS AND METHODS: From August 1998 to February 2007, 33 patients underwent tubeless PCNL for renal calculi by the same surgeon. A retrograde 7F ureteral catheter was placed at the beginning of the surgery in all patients. A nephrostomy tube was not used in any patient. At the end of the procedure, the working tract was electrocauterized using a 26F resectoscope with a rollerball electrode; no hemostatic sealant was used. The ureteral catheter was the sole means of drainage left in place. The incidence and type of complications, the operative time, the length of hospitalization, the rate of transfusion, and the degree of pain were obtained by chart review. RESULTS: In this group of patients, the mean stone burden was 17.25 mm. The mean operative time was 71.5 min. The mean length of hospitalization was 1.9 day (range 1 to 7 days). The mean hemoglobin decrease was 0.8 g/dL. No blood transfusions were needed. The mean visual analog pain intensity scale was 1.87. Complications developed in five (15%) patients, of whom one needed a Double-J stent placement. The complications were pyelonephritis, urinary extravasation, sustained hematuria, and renal colic. The ureteral catheter was removed by postoperative day 1 in 91% of patients. CONCLUSIONS: Replacing the Double-J stent with a ureteral catheter in tubeless PCNL is an effective procedure and can be performed in patients with a moderate stone burden. The electrocauterization of the bleeding points at the end of percutaneous renal surgery with a rollerball resectoscope is safe.

["Tubeless" percutaneous nephrolithotomy: a series of 37 cases]. / La néphrolithotomie percutanée "tubeless": à propos de 37 cas.

OBJECTIVE: To assess the value and feasibility of "tubeless" percutaneous nephrolithotomy (without postoperative nephrostomy tube). MATERIAL AND METHOD: Prospective study of 37 consecutive patients operated by "tubeless" percutaneous nephrolithotomy (PCNL) between 1998 and 2007 for renal stones. Inclusion criteria for this technique were: a single puncture tract, a procedure lasting less than 2 hours, <3 stones with a diameter <25 mm, complete extraction of all stones and no significant bleeding in the renal cavities at the end of the operation. A 7 Fr ureteric stent was inserted at the beginning of the operation in 33 patients and a double J stent was already present in the last four patients. All these stents were not remowed at the end of the procedure and the nephrostomy tract was electrocoagulated by a blunt electrocautery loop mounted on a 26 F resectoscope. No nephrostomy tube was left in place and no haemostatic product was used. Complications, length of hospital stay, operating time, blood loss, transfusions and intensity of pain were recorded. RESULT: The mean stone diameter was 172 mm. The mean percutaneous operating time was 72 min. The mean length of hospital stay was 1.9 days (range: 1 to 7 days). The success rate was 95% and the complication rate was 13.5%. Complications were: two cases of pyelonephritis, one case of prolonged haematuria, one case of renal colic and one case of urinary extravasation. The mean decrease in haemoglobin was 0.95 g/dl (range: 0 to 2 g/dl). The mean intensity of pain evaluated by visual analogue scale (VAS) was 1.9. No blood transfusion was required. The ureteric stent was removed on postoperative D1 in 91% of patients with a stent. CONCLUSION: "Tubeless" percutaneous nephrolithotomy is an effective and reproducible procedure with low morbidity that provides satisfactory results in selected cases.

[Angiomyolipoma with epithelioid contingent mimicking renal cell carcinoma]. / Angiomyolipome à composante épithélioïde mimant un adénocarcinome rénal.

The authors report the case of a patient followed for renal angiomyolipoma. On CT surveillance, this lesion developed features of a malignant tumour with loss of the fatty component and the patient was treated by nephrectomy. Histological examination demonstrated renal angiomyolipoma with an epithelioid contingent. The various aspects of this histological and radiological variant are discussed.