Pelvicalyceal anatomy on the accessibility of reusable flexible ureteroscopy to lower pole calyx during retrograde intrarenal surgery.

OBJECTIVE: This study aimed to evaluate the pelvicalyceal anatomy on accessibility of reusable flexible ureteroscopy (fURS) to the lower pole calyx during retrograde intrarenal surgery (RIRS). METHODS: Here, 854 patients with ureteral or kidney stones with access to a renal collecting system using reusable fURS were classified into either the accessible group, in whom the deepest lower pole calyces could be touched; and the inaccessible group, in whom the deepest lower calyces could not be touched. We measured the infundibulopelvic angle (IPA), infundibular width (IW), infundibular length (IL), and calyceal pelvic height (CPH) using retrograde pyelograms and performed intergroup comparisons. RESULTS: The median IPA, IW, IL, and CPH in the accessible and inaccessible group were 60.5° and 45.6° (p < 0.001), 10.8 and 9.4 mm (p < 0.001), 33.2 and 36.4 mm (p < 0.001), and 25.9 and 30.9 mm (p < 0.001), respectively. IPA (OR 0.963, 95% CI 0.952-0.974, p < 0.001) and IW (OR 0.519, 95% CI 0.331-0.816, p = 0.004) were significant risk factors of renal pelvicalyceal anatomy related to the accessibility of the lower pole calyces. The cut-off value for IPA and IW was 45.8°(p < 0.001) and 7.8 mm (p < 0.001), respectively. CONCLUSIONS: IPA < 45.8° and IW <7.8 mm were negative predictors to access the lower pole calyces when using reusable fURS during RIRS.

In-vitro and in-vivo new evidence for Flexor® Vue™ deflecting endoscopic system use: optimization of the stone free rate (SFR) after flexible ureteroscopy and Ho:YAG laser lithotripsy.

To test in-vitro and in-vivo the Flexor® Vue™ deflecting endoscopic system (FVDES) as a new technology able to improve the removal of residual intrarenal fragments.This is an observational prospective "proof of concept" study performed in patients with renal calculi treated with flexible ureteroscopy and Ho:YAG laser lithotripsy (f-URS) in Humanitas Research Hospital (Rozzano, Italy). We assessed feasibility, efficacy and safety of FVDES as an in-vivo tool for removing residual fragments after f-URS. The stone-free rate (SFR) at 30 days post-operatively was evaluated using CT. An in-vitro model was developed to evaluate the FVDES when used for this purpose.Eleven patients (M/F ratio: 7/4, mean age 63.5 ± 8.3) were treated. The stones were located in the lower calyces and the renal pelvis in 3 and 8 patients, respectively. Mean stone size was 18 ± 3.2 mm. The procedure with FVDES was feasible and effective in all the patients. Mean operative time was 82 ± 13.7 min and median hospitalization was of 1.5 days. The SFR after 90 days was 81% (9/11). We reported no relevant complications (Clavien-Dindo > 2); one patient had fever and was treated with antibiotics. The experimental in-vitro model demonstrated the efficacy of FVDES, allowing the removal of about 90% of fragments.Our study showed that FVDES is effective when used as a tool for retrieval of residual fragments at the end of f-URS. This technology could ensure a complete cleaning of the intrarenal collecting system and represent a safe alternative to basketing.

Proposal for a Simple Anatomical Classification of the Pelvicaliceal System for Endoscopic Surgery.

We herein propose a nomenclature for renal calices and anatomical classification of the renal pelvis for endoscopic surgery. We prospectively collected data on a total of 270 patients (540 kidneys) who underwent CT-urography. We then constructed three-dimensional images of the renal pelvis and examined their morphologic classification. Forty-eight kidneys were excluded from this study because of severe hydronephrosis or large renal cysts. The remaining 492 kidneys were included. We systematically categorized each minor calix into five levels: top, upper, middle, lower, and bottom. The upper, middle, and lower calices were typically found in pairs: anterior and posterior. The most common total number of minor calices was eight (51%), followed by seven (30%). We also classified the form of the pelvis into type I: single pelvis (58%) and type II: divided pelvis (42%), according to the branch patterns of the renal pelvis. In type II, the renal pelvis is always bifurcated into the upper branch (top and upper) and lower branch (middle, lower, and bottom). Type I was subclassified into three types: type Ia (43%), the standard type; type Ib (4%), with a wide pelvis; and type Ic (11%), with a narrow pelvis. This anatomical classification can divide the renal pelvis into two major types (subdivided into four types) and name each minor calix. This simple classification enables to share common intrarenal information, thus leading to the development of concrete treatment strategies.

Prediction of Intraoperative Urinary Collecting System Entry in Patients with Peripheral Renal Tumors Undergoing Partial Nephrectomy: Usefulness of Tumor-Centered Multiplanar Reconstruction.

OBJECTIVE: To assess the usefulness of tumor-centered multiplanar reconstruction (TC-MPR) for predicting intraoperative urinary collecting system (UCS) entry in patients with peripheral renal tumors undergoing partial nephrectomy (PN). METHODS: Dynamic computed tomography images of 50 peripheral cT1 renal tumors treated with laparoendoscopic PN were analyzed. TC-MPR generated a digital cross-sectional image showing the tumor center and the closest calyx on a same plane. Patients and tumor characteristics including the distance from the tumor margin to the closest calyx (MPR-distance), and the angle formed by 2 tangent lines from the closest calyx to the tumor (MPR-angle) were assessed. RESULTS: Intraoperative UCS entry was observed in 15 patients (30%). The patients who experienced intraoperative UCS entry had a higher RENAL score, wider MPR-angle, and shorter MPR-distance than those who did not (p = 0.04, p = 0.001, p < 0.001, respectively). Multivariate analysis identified MPR-angle as an independent factor for intraoperative UCS entry (p < 0.001). CONCLUSIONS: The spatial information assessed using TC-MPR serves as a predictive factor for intraoperative UCS entry during PN.

The Association of a Number of Anatomical Factors with the Success of Retrograde Intrarenal Surgery in Lower Calyceal Stones.

PURPOSE: To determine anatomical factors affecting Retrograde Intrarenal Surgery (RIRS) success in the treatment of renal lower calyx stones. MATERIALS AND METHODS: The results of patients were evaluated retrospectively. The patients who have preoperative intravenous urography (IVU) and computed tomography (CT) were divided into two groups as successful (S)(N=103) and unsuccessful(U) (N=29). The anatomic characteristics such as infundibulopelvic angle (IPA), infundibular length (IL), infundibular width (IW) and pelvicaliceal height (PCH) values were compared among two groups. RESULTS: Mean patient age was 47±13.6 years in group S and 49.5 ±11.9 years in group U. The mean stone size was 10mm (6-54mm) in group S and 19mm (8-45mm) in group U (P < .001) Mean IPA was 85.8 ±16.9 degree in group S versus 54.7 ± 11.5 degree in group U. The mean PCH was 1.9cm (0.5-4cm) in group S versus 2.3cm (0.7-3.9cm) in group U. The mean IL were 2.7 ± 0.8 cm and 3.2±0.7cm in group S and group U, respectively. The mean IWs were 0.7 cm (0.2-2.3cm) and 0.7cm (0.3-2) in group S and group U, respectively. The differences were statistically significant for IPA, PCH, IL (P < .05) while was not statistically significant for IW (P > .05). After multivariate analyses, PCH, IPA and stone size were statistically significant factors. CONCLUSION: In our study we found that IPA, PCH and stone size were significant anatomical factors affecting RIRS success in the treatment of renal lower calyx stones. The patients whose IPA, PCH and stone size valuables are unsuitable, may need multiple RIRS sessions or additionaltreatment modalities.

Anatomical study of the renal excretory system in pigs. A review of its characteristics as compared to its human counterpart.

BACKGROUND: Despite the importance of the pyelocalyceal system in the pig as an experimental model, there is little information about this particular anatomical subject. We determined the morphological characteristics of the renal excretory system in pigs. MATERIALS AND METHODS: This descriptive cross-sectional study evaluated 130 pairs of kidneys of pigs destined to slaughter. The pyelocalyceal system was subjected to injection technique - corrosion by infusion of polyester resin (85% Palatal and 15% Styrene) and subsequent infusion in potassium hydroxide (KOH) for 10 days. The significance level used was p < 0.05. RESULTS: The renal excretory system is characterised by the presence of type A major cranial and caudal calyxes seen in 34.3% of the kidneys (type A1 in 30% and type A2 in 4.3%). type B calyxes, corresponding to minor calyxes draining directly into the renal pelvis, were present in 65.7% of the specimens (type B1 59.2%; type B2 6.5% of the cases). The number of minor calyxes in the collector system was 7.9 ± 2.27 with statistically significant differences in side (p = 0.0047). CONCLUSIONS: The morphometric characteristics of the kidneys in this study are slightly smaller than reported in humans. Similarly, the incidence of type A renal excretory system distribution is highest in humans and lowest in pigs. Due to its few morphological differences, the pig kidney is an excellent model for teaching- -learning processes, for research purposes, and for training of urologic applications.

Impact of Three-Dimensional Printed Pelvicaliceal System Models on Residents' Understanding of Pelvicaliceal System Anatomy Before Percutaneous Nephrolithotripsy Surgery: A Pilot Study.

OBJECTIVE: To investigate the impact of three-dimensional (3D) printed pelvicaliceal system models on residents' understanding of pelvicaliceal system anatomy before percutaneous nephrolithotripsy (PCNL). MATERIALS AND METHODS: Patients with unilateral complex renal stones indicating PCNL were selected. Usable data of patients were obtained from CT-scans in Digital Imaging and Communications in Medicine (DICOM) format. Mimics software version 16.0 (Materialise, Belgium) was used for segmentation and extraction of pelvicaliceal systems (PCSs). All DICOM-formatted files were converted to the stereolithography file format. Finally, fused deposition modeling was used to create plasticine 3D models of PCSs. A questionnaire was designed so that residents could assess the 3D models' effects on their understanding of the anatomy of the pelvicaliceal system before PCNL (Fig. 3). RESULTS: Five patients' anatomically accurate models of the human renal collecting system were effectively generated (Figs. 1 and 2). After presentation of the 3D models, residents were 86% and 88% better at determining the number of anterior and posterior calices, respectively, 60% better at understanding stone location, and 64% better at determining optimal entry calix into the collecting system (Fig. 5). CONCLUSION: Generating kidney models of PCSs using 3D printing technology is feasible, and the models were accepted by residents as aids in surgical planning and understanding of pelvicaliceal system anatomy before PCNL.

Influence of the renal lower pole anatomy and mid-renal-zone classification in successful approach to the calices during flexible ureteroscopy.

PURPOSE: The aim of this paper is to analyze if the anatomy type of the collector system (CS) limits the accessibility of flexible ureteroscopy (FUR) in the lower pole. METHODS: We analyzed the pyelographies of 51 patients submitted to FUR and divided the CS into four groups: A1-kidney midzone (KM) drained by minor calices (Mc) that are dependent on the superior or on the inferior caliceal groups; A2-KM drained by crossed calices; B1-KM drained by a major caliceal group independent both of the superior and inferior groups, and B2-KM drained by Mc entering directly into the renal pelvis. We studied the number of calices, the angle between the lower infundibulum and renal pelvis, and the angle between the lower infundibulum and the inferior Mc. With the use of a flexible ureteroscope, the access attempt was made to all of lower pole calices. Averages were statistically compared using the ANOVA and Unpaired T test (p < 0.05). RESULTS: We found 14 kidneys of A1 (27.45 %); 4 of A2 (7.84 %); 17 of B1 (33.33 %); and 16 of B2 (31.37 %). The LIP was >90° in 31 kidneys (60.78 %) and between 61° and 90° in 20 kidneys (39.22 %). We did not find angles smaller than 60°. The group A1 presented 48 Mc and the UF was able to access 42 (87.5 %); the group A2 had 11 Mc and the UF was able to access 7 (63.64 %); the group B1 had 48 Mc and the UF was able to access 41 (85.42 %) and in group B2 we observed 41 Mc and the UF could access 35 (85.36 %). There was no statistical difference in the accessibility between the groups (p = 0.2610). CONCLUSIONS: Collecting system with kidney midzone drained by crossed calices presented the lower accessibility rate during FUR.

The role of middle calyx puncture in percutaneous nephrolithotomy: relative factors and choice considerations.

Percutaneous nephrolithotomy (PCNL) is a well established procedure for management of renal calculi. It is generally believed that the access to the renal pelvic system via the desired calyx is the most crucial step during the whole procedure. The adequacy of the access directly influences the success and complication rates of PCNL. Traditionally, a lower pole access was routinely performed for less complication. Upper calices are also preferred for access in a given condition with large and complex calculi. However, the middle calices access is seldom selected. In aim to provide the reader some advantages of middle pole approach and a broaden horizon in determining the strategy of renal puncture, the present review describes the anatomical basis of the percutaneous tract. It provides a literature review of the success rate and efficiency of middle calyx access alone with the advantage of this approach, especially in dealing with large and complex stones.

Lower pole anatomy and mid-renal-zone classification applied to flexible ureteroscopy: experimental study using human three-dimensional endocasts.

PURPUSE: The aim of this study was to analyze the anatomy of the inferior pole collecting system and the mid-renal-zone classification in human endocasts applied to flexible ureteroscopy. METHODS: 170 three-dimensional polyester resin endocasts of the kidney collecting system were obtained from 85 adult cadavers. We divided the endocasts into four groups: A1--kidney midzone (KM), drained by minor calices (mc) that are dependent on the superior or the inferior caliceal groups; A2--KM drained by crossed calices; B1--KM drained by a major caliceal group independent of both the superior and inferior groups; and B2--KM drained by mc entering directly into the renal pelvis. We studied the number of calices, the angle between the lower infundibulum and renal pelvis and the angle between the lower infundibulum and the inferior mc (LIICA). Means were statistically compared using ANOVA and the unpaired T test (p < 0.05). RESULTS: We found 57 (33.53 %) endocasts of group A1; 23 (13.53 %) of group A2; 59 (34.71 %) of group B1; and 31 (18.23 %) of group B2. The inferior pole was drained by four or more calices in 84 cases (49.41 %), distributed into groups as follows: A1 = 35 cases (41.67 %); A2 = 18 (21.43 %); B1 = 22 (26.19 %); and B2 = 9 (10.71 %). Perpendicular mc were observed in 15 cases (8.82 %). We did not observe statistical differences between the LIICA in the groups studied. CONCLUSIONS: Collector systems with kidney midzone drained by minor calices that are dependent on the superior or on the inferior caliceal groups presented at least two restrictive anatomical features. The mid-renal-zone classification was predictive of anatomical risk factors for lower pole ureteroscopy difficulties.

Stone scattering during percutaneous nephrolithotomy: role of renal anatomical characteristics.

The purpose of this study was to evaluate how the upper calyx-lower calyx infundibular (ULI) angle influences intrarenal stone migration during percutaneous nephrolithotomy (PCNL) in patients with a solitary renal pelvis stone and significant hydronephrosis. 50 adult patients with a solitary renal pelvis stone larger than 20 mm were considered for PCNL with a pneumatic lithotriptor for stone fragmentation. Inclusion criteria were moderate to severe hydronephrosis and upper calyx infundibular width >10 mm, and access point was the lower calyx in all cases. The ULI angle as well as stone fragment migration from the renal pelvis toward the upper calyx was noted during the operation. To determine the "critical" angle above which the probability of stone migration would be increased significantly, receiver operating characteristic curve was used. Mean stone size was 33.8 ± 13.2 mm. In 23 patients (46 %) the stone migrated toward the upper calyx during stone fragmentation. Mean ULI angle was significantly wider in patients whose stone migrated (120.2 ± 20.5 versus 102.2 ± 21.4, P = 0.004, 99 % CI = 6.04-29.9). A ULI angle of 117.5° was the critical angle, above which the rate of stone migration rose significantly (P < 0.008). One-session stone-free rate was significantly higher in patients without stone migration (P = 0.03). In patients with a solitary renal pelvis stone and significant hydronephrosis, a wider ULI angle was associated with a greater likelihood of stone scattering which could potentially affect the outcome of PCNL with pneumatic lithotriptor. A cut-off angle of 117.5° was the critical angle, above which access via a calyx other than the lower calyx (example: middle or upper calyx) seems advisable.

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

PURPOSE: We 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 METHODS: Height, 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). RESULTS: BMI 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. CONCLUSION: SCD 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.

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.

The presence and distribution of alpha adrenergic receptors in human renal pelvis and calyces.

In this study, we aimed to demonstrate the presence of Alpha (α) 1 receptors and subtypes in human pelvis and calyces, because an agent to facilitate kidney stone movement and help decrease pain may be an α 1 adrenergic blocker, as used in ureteral stones. Twenty patients who applied to our clinic for renal cell carcinoma were enrolled to the study. All patients underwent radical nephrectomy. After the specimens were removed, excisional biopsies were performed on healthy pelvises and calyces. Mean α-receptor stain rates in renal pelvis were 2.65 ± 0.74, 1.35 ± 0.81 and 2.9 ± 0.30 for α 1A, 1B and 1D, respectively. For calyces, the rates are 2.40 ± 0.82, 1.50 ± 0.76 and 2.75 ± 0.44 for α 1A, 1B and 1D, respectively (Fig. 1). When the staining patterns were compared, α 1A and 1D were expressed more in both pelvis and calyces than α 1B (p < 0.05). After the demonstration of α-adrenergic receptors in pelvis and calyces of human kidney, it may be helpful in coming up with new alternative treatments for patients suffering from kidney stones.

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.

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. .

Renal calyceal anatomy characterization with 3-dimensional in vivo computerized tomography imaging.

PURPOSE: Calyceal selection for percutaneous renal access is critical for safe, effective performance of percutaneous nephrolithotomy. Available anatomical evidence is contradictory and incomplete. We present detailed renal calyceal anatomy obtained from in vivo 3-dimentional computerized tomography renderings. MATERIALS AND METHODS: A total of 60 computerized tomography urograms were randomly selected. The renal collecting system was isolated and 3-dimensional renderings were constructed. The primary plane of each calyceal group of 100 kidneys was determined. A coronal maximum intensity projection was used for simulated percutaneous access. The most inferior calyx was designated calyx 1. Moving superiorly, the subsequent calyces were designated calyx 2 and, when present, calyx 3. The surface rendering was rotated to assess the primary plane of the calyceal group and the orientation of the select calyx. RESULTS: The primary plane of the upper pole calyceal group was mediolateral in 95% of kidneys and the primary plane of the lower pole calyceal group was anteroposterior in 95%. Calyx 2 was chosen in 90 of 97 simulations and it was appropriate in 92%. Calyx 3 was chosen in 7 simulations but it was appropriate in only 57%. Calyx 1 was not selected in any simulation and it was anteriorly oriented in 75% of kidneys. CONCLUSIONS: Appropriate lower pole calyceal access can be reliably accomplished with an understanding of the anatomical relationship between individual calyceal orientation and the primary plane of the calyceal group. Calyx 2 is most often appropriate for accessing the anteroposterior primary plane of the lower pole. Calyx 1 is most commonly oriented anterior.

Pelvi-caliceal collecting system in swine--authors own anatomical classification.

BACKGROUND: Experiments on humans and their organs produce legal, moral and ethical dilemmas. Nowadays, the use of domestic swine as an experimental animal is increasing steadily. Thus it is important to know the structure and characteristics of swine organs. OBJECTIVES: The purpose of the study was to investigate the shape, dimensions and volume of the renal collecting system in swine, based on authors own outline of division of this anatomical structure, as well as comparing some features of the pelvi-caliceal collecting system for swine and man. MATERIAL AND METHODS: The study was carried out on 36 kidneys of adult swine (Sus scrofa domestica) of both sexes. The authors generated the corrosion specimens by applying Plastogen G. The authors took the density of the stained and hardened mass into consideration and weighed the corrosion casts. Then the authors could estimate the volume of the pelvi-caliceal collecting system by applying the formula which states that volume is a quotient of weight and density. RESULTS: The mean dimensions of the pelvi-caliceal collecting system in swine are: length--69.2 mm, width--23.5 mm, thickness--15.8 mm; the volume of this system is on average 7.0 cm3. The renal collecting system originates from the minor calices which are in the shape of flattened cones. Their mean dimensions are: diameter--9.3 mm, height--3 mm. The major calices, taking the form ofa cylindrical body, emerge from the minor calices. The mean dimensions of the primary major calices inserted in the renal pelvis are: length--.0 mm, diameter--6 mm; the primary calices which come into secondary ones: length--7 mm, diameter--3 mm; the secondary major calices: length--.3 mm, diameter--0 mm. The renal pelvis is the last part of the pelvi-caliceal collecting system and takes the form of a distorted triangle. Its mean dimensions are: width--.1 mm, height--.7 mm. CONCLUSIONS: The pelvi-caliceal collecting system in swine is a massive structure of high volume, with a well-developed structure of the renal calices and swollen renal pelvis. The studied structure is more massive and its volume is about three times larger than that in man. Despite some disadvantages, perhaps in the future a swine kidney will be transplanted into a man, but nowadays due to lack of dissection material it may be used as a teaching model or in experimental research.