The skin-to-calyx distance measured by renal ct scan and ultrasound

PurposeWe developed a stereotactic device to guide the puncture for percutaneous nephrolithotripsy, which uses the distance from the target calyx to its perpendicular point on skin (SCD) to calculate the needle´s entry angle. This study seeks to validate the use of measurements obtained by ultrasound (US) and computerized tomography (CT) for needle´s entry angle calculation and to study factors that may interfere in this procedure.Materials and MethodsHeight, weight, abdominal circumference, CT of the urinary tract in dorsal decubitus (DD) and ventral decubitus (VD), and US of the kidneys in VD were obtained from thirty-five renal calculi patients. SCD obtained were compared and correlated with body-mass index (BMI).ResultsBMI was 28.66 ± 4.6 Kg/m2. SCD on CT in DD was 8.40 ± 2.06cm, in VD was 8.32 ± 1.95cm, in US was 6.74 ± 1.68cm. SCD measured by US and CT were statistically different (p < 0.001), whereas between CT in DD and VD were not. SCD of the lower calyx presented moderate correlation with BMI.ConclusionSCD obtained by CT in ventral and dorsal decubitus may be used for calculation of the needle´s entry angle. SCD obtained by US cannot be used. A rule for the correlation between BMI and the SCD could not be determined.

Predicting calyceal access for percutaneous nephrolithotomy with computed tomography multiplanar reconstruction

OBJECTIVES: Objective parameters in computed tomography (CT) scans that could predict calyceal access during percutaneous nephrolithotomy have not been evaluated. These parameters could improve access planning for percutaneous nephrolithotomy. We aimed to determine which parameters extracted from a preoperative multiplanar reconstructed CT could predict renal calyceal access during a percutaneous nephrolithotomy. METHODS: From January 2009 through April 2011, 230 patients underwent 284 percutaneous nephrolithotomies at our institution. Sixteen patients presented with complete staghorn calculi, and 11 patients (13 renal units) were analyzed. Five parameters were extracted from a preoperative reconstructed CT and compared with the surgical results of percutaneous nephrolithotomy. RESULTS: Fifty-eight calyces were studied, with an average of 4.4 calyces per procedure. A rigid nephroscope was used to access a particular calyx, and a univariate analysis showed that the entrance calyx had a smaller length (2.7 vs. 3.98 cm, p = 0.018). The particular calyx to be accessed should have a smaller length (2.22 vs. 3.19 cm, p = 0.012), larger angles (117.6 vs. 67.96, p<0.001) and larger infundibula (0.86 vs. 0.61 cm, p = 0.002). In the multivariate analysis, the only independent predictive factor for accessing a particular calyx was the angle between the entrance calyx and the calyx to be reached (OR 1.15, 95% confidence interval [CI], 1.053-1.256, p = 0.002). CONCLUSION: The angle between calyces obtained by multiplanar CT reconstruction is the only predictor of calyx access. .

Can infundibular height predict the clearance of lower pole calyceal stone after extracorporeal shockwave lithotripsy?

PURPOSE: To evaluate the efficacy of extracorporeal shock wave lithotripsy (SWL) on lower calyceal calculi in relation to the renal anatomical factors and determine which of these factors can be used to select patients who will benefit from SWL. MATERIAL AND METHODS: We analyzed retrospectively 78 patients with single radiopaque lower calyceal stones treated with SWL. The patients were evaluated 3 months after lithotripsy with a simple abdominal X-ray and a kidney ultrasound scan. The success of the treatment, removal of all fragments, was correlated with renal anatomical factors measured in the pre-treatment intravenous urography: infundibulopelvic angle, lower infundibulum width, lower infundibulum length, ratio length/width, infundibulum height, and number of minor calyces in the lower calyceal group. RESULTS: Three months after SWL treatment, 39 patients were stone-free (NR group) and 39 had residual fragments (R group). Both groups presented no differences in relation to infundibulopelvic angle, width and length of the lower calyceal infundibulum, length/width ratio of the lower infundibulum or number of lower calyces. Height of the infundibulum, described as the distance between the line passing through the lowest part of the calyx containing the calculus and the highest point of the lower lip of renal pelvis, was the only parameter in which significant differences (p = 0.002) were found between the NR and R groups. CONCLUSIONS: Lower Infundibular height could be a good measurement tool for deciding which patients with lower calyceal lithiasis would benefit from SWL treatment. Height of less than 22 mm suggests a good outcome from lithotripsy.

The impact of pelvicaliceal anatomical variation between the stone-bearing and normal contralateral kidney on stone formation in adult patients with lower caliceal stones

OBJECTIVE: We aimed to investigate the effect of pelvicaliceal anatomical differences on the etiology of lower caliceal stones. MATERIALS AND METHODS: Records of adult patients between January 1996 and December 2005 with solitary lower caliceal stone were reviewed. After exclusion of patients with hydronephrosis, major renal anatomic anomalies, non-calcium stones, history of recurrent stone disease and previous renal surgery, 78 patients were enrolled into the study. Lower pole infundibulopelvic angle (IPA), infundibulovertebral angle (IVA), infundibular length (IL), width (IW), number of minor calices and cortical thickness of the lower pole together with other caliceal variables obtained from the whole pelvicaliceal anatomy of both stone-bearing and contralateral normal kidneys were measured from intravenous pyelogram of the patients. Total pelvicaliceal volume was also calculated by a previously described formula for both kidneys. RESULTS: There were statistically significant difference between two kidneys in terms of IW (p < 0.001) and IL (p = 0.002) of the upper calyx, IW (p = 0.001) and IVA (p < 0.001) of the lower calyx), pelvicaliceal volume (p < 0.001), IPA of middle calyx (p = 0.006) and cortical thickness over the lower pole (p < 0.001). However there was no difference between stone-bearing and contralateral normal kidneys in terms of lower pole IPA (p = 0.864) and IL (p = 0.568). CONCLUSION: Pelvicaliceal volume but not lower caliceal properties seem to be a risk factor for stone formation in lower calyx.

Morphological study of the pyelo-calyce-pyramidal system in human kidney

Los autores estudiaron el sistema pielo-cálice-piramidal en relación a los aspectos siguientes: número de pirámides renales, número de cálices mayores, número de cálices menores y forma de la pélvis renal. Fueron utilizados 80 riñones humanos, derechos e izquierdos, provenientes de cadáveres adultos, de ambos sexos, con distintas causas de muerte, previamente fijados en formol al 10 por ciento. Este material fué disecado para extraer restos peritoneales y tejido pararrenal. Luego, los riñones fueron seccionados frontalmente a nivel del seno renal para el retiro de los vasos, nervios y grasa perirrenal. La media correspondiente a las pirámides renales, cálices mayores y cálices menores fueron, respectivamente: 8,26ñ1,38; 2,13ñ0,4 y 7,96ñ1,44. La relación entre el número de cálices menores y cálices mayores fue 3,74 y entre pirámides renales y cálices menores fue 1,04. En relación a la forma de la pelvis renal, se observó el predominio del tipo bifurcado simple en el 43,75 por ciento; seguida de las formas ramificada, en el 20 por ciento, bifurcada alargada, en el 12,5 por ciento, trifurcada, en el 11,25 por ciento y ampollar, en el 10 por ciento de los casos. En 2,5 de las observaciones, se verificó la presencia de una pelvis renal doble