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Lower-caliceal stone clearance index to predict clearance of stone after SWL.

BACKGROUND AND PURPOSE: There is no uniform consensus regarding the anatomic factors that influence the clearance rate of caliceal stones after SWL, as different authors have studied various independent factors separately. We correlated both favorable and unfavorable factors into a formula to predict the clearance rate. PATIENTS AND METHODS: A series of 56 consecutive patients (37 male, 19 female) with isolated lower-caliceal single stones (right 29, left 27) treated with SWL using the Dornier Compact Delta lithotripter were analyzed retrospectively. Of these, 40 patients had soft stones, and 16 patients had hard stones. The first stone-free rate (SFR) according to plain films and ultrasonography was analyzed by stone size, and a stone clearance index (SCI) formula was applied to see if there was any change in the SFR, especially for stones >2 cm. RESULTS: The formula, which correlated well with the clearance, is SCI = [(IVA x IW x stone type)/IH] - (stone size in mm(2)/10). Nearly all (90%) of the patients with an SCI of >0 cleared their stones within 3 months, and 87% of the patients with an SCI <0 cleared their stones after 3 months. Positive and negative predictive values were 93.33% and 76.9%, respectively. The accuracy of the correlation is 85.71%. CONCLUSIONS: The success of SWL for lower-caliceal stones can be predicted easily using the SCI. Stones of >200 mm(2) (>2 cm) surface area may still be suitable for SWL if the SCI is positive, whereas alternative treatment modalities should be considered if the SCI is a low negative value (<-7).

Evidence-Based Medicine↗

The impact of caliceal pelvic anatomy on stone clearance after shock wave lithotripsy for pediatric lower pole stones.

PURPOSE: The clearance rather than stone disintegration of lower pole stones after shock wave lithotripsy (SWL) is significantly inferior according to the other localizations of the kidney. We retrospectively evaluated the impact of caliceal pelvic anatomy on stone clearance after SWL for pediatric lower pole stones. MATERIALS AND METHODS: We treated 163 renal units (RUs) in children 16 years old or younger with SWL between March 1992 and February 2002. In 36 RUs stones were localized in the lower calices. All patients were treated with sedoanalgesia except 3 (8%) who were treated under general anesthesia. Patients were evaluated by excretory urography and ultrasonography 12 weeks after the last session, and were designated as stone-free or with residual stone. The lower infundibular length, width, length-to-width ratio, pelvic caliceal height and lower infundibulopelvic angle were determined on standard excretory urography before SWL. All measurements were done by 1 urologist who was unaware of the results. Statistical analysis was performed with chi-square, Fisher's exact and Mann-Whitney U tests. ROC analysis was done to determine the cutoff points of caliceal anatomy measurements for stone clearance. RESULTS: We treated 36 RUs in 23 males and 10 females with isolated lower caliceal stones. Median patient age was 10.5 years (range 2 to 16). Median stone burden was 0.7 cm (range 0.2 to 4), and median number of shock waves and energy used for the entire patient population was 1,500 and 17.2 kV, respectively. Overall stone-free rates for the 36 RUs were 61% after a median treatment session of 1 (range 1 to 7) and retreatment rates were 39%. Of the patients rendered free of stones 13 (59%) were treated in a single SWL session and 9 (41%) underwent 2 or more sessions. Median lower infundibular length, width, length-to-width ratio and pelvic caliceal height in the stone-free and residual stone group were 25.5, 28.0 mm, 4.5, 5.0 mm, 6.4, 5.5 mm and 21.5, 21.5 mm, respectively (p = 0.810, 0.327, 0.511 and 0.511). Median lower infundibulopelvic angle in the stone-free and residual stone groups was 92.50 and 92.50 degrees, and 60.0 and 54.50 degrees, respectively (p = 0.860 and 0.089). On ROC analysis no parameter predicting stone-free rate and cutoff points of caliceal anatomy measurements for stone clearance was found. CONCLUSIONS: Our results suggest that caliceal pelvic anatomy in pediatric lower pole stones has no significant impact on stone clearance after SWL. There was a highly significant relation between retreatment rates and stone burden, which should be considered for determining the treatment modality.

Adolescent↗

Predictors of lower pole renal stone clearance after extracorporeal shock wave lithotripsy.

PURPOSE: Lower pole renal stones are well known to show a poor stone clearance rate after extracorporeal shock wave lithotripsy (ESWL) (Dornier Medical Systems, Marietta, Georgia). In the current study we analyzed several anatomical factors as predictors of lower pole stone clearance that may be used to indicate the usefulness of ESWL in such patients. MATERIALS AND METHODS: Between January 1993 and October 2000, 63 patients with a unilateral single lower pole stone of 2 cm. or less were included in the study. Excretory urography was done to determine the lower infundibulopelvic angle, caliceal pelvic height, lower infundibular length and diameter, lower infundibular length-to-diameter ratio and number of lower pole minor calices. Stone-free status was assessed by x-ray. RESULTS: The overall stone clearance rate was 54% (34 of 63 patients). While caliceal pelvic height, lower infundibular diameter, length, length-to-diameter ratio and number of minor calices were different in the stone-free and residual stone groups on univariate analysis, multivariate logistic analysis revealed that the lower infundibular length-to-diameter ratio, diameter and number of minor calices were independent predictors of successful stone clearance. The 13 patients (20.6%) who showed all 3 favorable anatomical factors (lower infundibular length-to-diameter ratio less than 7, diameter greater than 4 mm. and a single minor calix) achieved an impressive 84.6% stone clearance rate. In patients with only 1 or 2 favorable factors the stone clearance rate was still greater than 60%. In contrast, the stone clearance rate was only 6.7% in the 15 patients who showed none of these factors. CONCLUSIONS: From this study it is apparent that successful ESWL is highly sensitive to the anatomy of the lower pole of the kidney. If a patient with a lower pole stone has at least 1 of the favorable factors identified in this study, ESWL may be advocated as first line therapy with a greater than 60% prospect of a successful outcome. Other treatment options should be considered in those without any of these predictive factors.

Adult↗

[Usefulness of lower ihfundibular length-to-diameter ratio as a predictor of lower pole stone clearance after extracorporeal shock wave lithotripsy; clinical research with two lithotriptors].

PURPOSE: Lower pole renal stones are well known to exhibit a poor stone clearance rate following extracorporeal shock wave lithotripsy (ESWL). In the present study, we analyzed several anatomical factors as predictors of lower pole stone clearance that may be used to indicate the usefulness and the universality of ESWL in such patients with two different lithotriptors. PATIENTS AND METHODS: 93 patients with a unilateral single lower pole stone of 2 cm. or less underwent ESWL using Piezolith 2500 or Medstone STS, were included in the study. An IVP was used to determine the lower infundibulopelvic angle, the caliceal pelvic height, the lower infundibular length, the lower infundibular diameter, the lower infundibular length-to-diameter ratio and the number of lower pole minor calyces. Stone-free status was assessed by a plain film with or without renal ultrasound. RESULTS: The stone clearance rate at the Piezolith 2500 group was 53.1% (34 of 64 patients), while was 51.7% (15 of 29 patients) at the Medstone STS group. In all cases, the overall stone clearance rate was 52.7% (49 of 93 patients). Age, laterality of the stone burden within the kidney and stone size were not different between the stone-free and residual stone groups. Multivariate logistic analysis revealed that length-to-diameter ratio was the most independent predictors of successful stone clearance at each group. The patients exhibited length-to-diameter ratio less than 7 achieved high stone clearance rates, greater than 72%. In contrast, the stone clearance rate was less than one third when length-to-diameter ratio was 7 or greater. Besides length-to-diameter ratio was strong prognostic factor in patients with stones 1 cm. or less and 1 to 2 cm at each group. CONCLUSION: From this study, it is apparent that successful ESWL is highly sensitive to the anatomy of the lower pole of the kidney. Especially, the lower infundibular length-to-diameter ratio is potentially useful and a universal predictor regardless of the kind of lithotriptors at least in patients with a lower pole radiopaque stone 2 cm. or less treated with ESWL.

Adolescent↗

Low pretreatment gallbladder stone densities at computed tomography predict rapid stone clearance following extracorporeal shock wave lithotripsy.

The importance of routine computer tomographic (CT) stone analysis in optimizing the therapeutic outcome after extracorporeal shock wave lithotripsy (ESWL) remains controversial. The aim of the present prospective study was to seek a correlation between CT findings and stone clearance rates after ESWL in 159 patients. One hundred fifty-nine symptomatic patients (116 females, 43 males) with solitary radiolucent gallbladder stones underwent CT for stone analysis before lithotripsy. In Group I (<50 HU, n=104), stone clearance was achieved in 55.8% of patients within 6.11+/- 6.95 months; in Group II (51-100 HU, n = 28), in 50.0% of patients within 11.2 +/- 10.3 months; in Group III (>100 HU, n = 27) in 29.7% of patients within 9.60 +/- 6.96 months. The mean follow-up period was 17.9 +/- 10.0 months. Patients in Group I showed a significantly higher rate of stone clearance than those in Groups II and III (p < 0.001) as well as a significantly shorter time for the achievement of total stone clearance than either of the other groups (p < 0.001). The authors conclude that CT stone analysis provides a more accurate method of selecting patients suitable for ESWL and may be of importance in predicting the expected length of time for achieving complete stone clearance.

Absorptiometry, Photon↗

Rapid extracorporeal shock wave lithotripsy treatment after a first colic episode correlates with accelerated ureteral stone clearance.

OBJECTIVES: To investigate the relationship between delay in extracorporeal shock wave lithotripsy (ESWL) after a first colic and subsequent time to complete stone clearance. METHODS: This prospective, non-randomized study included 94 patients treated with ESWL for unilateral solitary proximal ureteral stones after at least one episode of colic pain. Time between the first onset of colic pain and ESWL and stone clearance was recorded. The pretherapeutic degree of hydronephrosis has been assessed using ultrasound. RESULTS: Mean stone size was 7.9 +/- 2.3 mm and mean time before ESWL after a first colic was 93.4 +/- 143.5 h. At 3 months, 3 patients were lost to follow-up. In 76.9% of patients stones were completely cleared and a further 3.3% harbored residual fragments < or =3 mm. Delay in treatment after a first colic correlated with subsequent time to stone clearance (p < 0.0001). Mean time to stone clearance in patients treated within 24h was 6.4 +/- 6.3 days compared with 16.0 +/- 17.8 days for those treated later (p = 0.008). Maximum stone diameter correlated with time to stone clearance (p = 0.031), but the degree of hydronephrosis did not. CONCLUSIONS: Rapid ESWL after a first onset of colic pain resulted in accelerated stone clearance independent of the degree of hydronephrosis but had no impact on the need for auxiliary procedures.

Adult↗

Prediction of lower pole stone clearance after shock wave lithotripsy using an artificial neural network.

PURPOSE: We performed this study as a comprehensive evaluation of variables reported to affect lower pole stone clearance after shock wave lithotripsy using artificial neural network analysis. MATERIALS AND METHODS: The radiographic images and treatment records of 680 patients with lower pole renal calculi treated with primary shock wave lithotripsy using the Wolf Piezolith 2500 (Wolf, Knittlingen, Germany) lithotriptor were retrospectively evaluated by applying artificial neural network analysis. Successful stone clearance was defined as absent fragments of any size detected on plain x-ray with tomography and/or excretory pyelography performed 6 months after treatment. Prognostic variables included patient characteristics, laboratory values, stone characteristics and the spatial anatomy of the lower pole, as defined by infundibular length, diameter, caliceal pelvic height, 2 measurements of the lower infundibulopelvic and infundibuloureteropelvic angles as well as the pattern of dynamic urinary transport. RESULTS: Artificial neural network analysis had 92% accuracy for correctly predicting lower pole stone clearance. The pattern of dynamic urinary transport represented the most influential predictor of stone clearance, followed by a measure of the infundibuloureteropelvic angle, body mass index, caliceal pelvic height and stone size. Anatomical measurements of lower pole anatomy and classification of the type of urinary transport were well reproducible with low intra-observer and interobserver variability (correlation coefficient alpha >0.8). CONCLUSIONS: In a comprehensive analysis of variables reported to influence lower pole stone clearance artificial neural network analysis predicted stone clearance with a high degree of accuracy. The relative importance of dynamic urinary transport in lower pole stones and the usefulness of artificial neural network analysis to predict shock wave lithotripsy outcomes in individuals must be confirmed in a prospective trial.

Adolescent↗

Role of External Vibratory Lithoclast (Lithecbole) in Improving Lower Pole Stone Clearance After Extracorporeal Shock Wave Lithotripsy (ESWL).

<b>Background and Objective:</b> Extracorporeal shock wave lithotripsy (ESWL) is a widely used non-invasive treatment for renal stones. However, its effectiveness in clearing stones located in the lower pole of the kidney is often limited due to the anatomical challenges that impede the spontaneous passage of fragmented stones. This study evaluate the efficacy and safety of External Physical Vibration Lithecbole (EPVL) when used as an adjunctive therapy following ESWL in patients with lower pole renal stones, with a focus on improving stone clearance rates. <b>Materials and Methods:</b> This prospective interventional study was conducted at Al Yarmouk Teaching Hospital over two years and included 100 patients with 10-15 mm lower pole renal stones. Patients were randomized into two groups: The ESWL alone and ESWL plus EPVL. All patients received two ESWL sessions (3000 shocks/session). The treatment group additionally received EPVL therapy using a flank-applied vibration device. Follow-up was performed using ultrasound and KUB radiography. Statistical analysis was conducted using appropriate tests with significance set at p<0.05. <b>Results:</b> Baseline characteristics, including age, gender, weight, stone size and location, were statistically comparable between groups. The mean stone size was 12.4&#xb1;1.7 mm. A significantly higher stone-free rate was observed in the ESWL+EPVL group compared to the ESWL-only group (66% vs. 48%, p = 0.027). Although the residual stone size showed a numerical difference favoring EPVL, it was not statistically significant (p = 0.11). Complication rates were low, mild and similar in both groups (p = 0.3). Logistic regression analysis revealed that smaller stone size (p<0.001) and lower patient weight (p = 0.030) were significantly associated with successful stone clearance. Subgroup analysis further confirmed that patients with stones <11 mm or a weight <70 kg had the highest stone-free rates. <b>Conclusion:</b> In this initial evaluation, EPVL demonstrated a safe and effective adjunct to ESWL in enhancing stone clearance for lower-pole renal stones. Its application was associated with improved treatment outcomes without increasing complication rates. Further studies with extended EPVL sessions and longer follow-up are warranted.

Humans↗

Lower caliceal stone clearance after shock wave lithotripsy or ureteroscopy: the impact of lower pole radiographic anatomy.

PURPOSE: We determine whether there is a significant relationship between the spatial anatomy of the lower pole, as seen on preoperative excretory urography (IVP), and the outcome after shock wave lithotripsy or ureteroscopy for a solitary lower pole caliceal stone 15 mm. or less. MATERIALS AND METHODS: Between January 1992 and June 1996, 34 patients with 15 mm. or less solitary lower pole stone underwent ureteroscopy with intracorporeal lithotripsy (13) or extracorporeal shock wave lithotripsy (ESWL) with a Dornier HM3 lithotriptor (21). On pretreatment IVP lower pole infundibular length and width, infundibulopelvic angle of the stone bearing calix were measured. Stone size and area were determined from an abdominal plain x-ray. A plain x-ray of the kidneys, ureters and bladder was obtained in all patients at a median followup of 12.3 and 8 months in the ureteroscopy and ESWL groups, respectively. RESULTS: After initial therapy the overall stone-free rate was 62 and 52% in the ureteroscopy and ESWL groups, respectively. Stone-free status after ESWL was significantly related to each anatomical measurement. Infundibulopelvic angle 90 degrees or greater, and infundibular length less than 3 cm. and width greater than 5 mm. were each noted to correlate with an improved stone-free rate after ESWL. In contrast, the stone-free rate after ureteroscopy was not statistically significantly impacted by these anatomical features, although a clinical stone-free trend was identified relating to a favorable infundibular length and infundibulopelvic angle. The infundibulopelvic angle was 90 degrees or greater in 4 stone-free patients (12% overall), including 2 who underwent ureteroscopy and 2 who underwent ESWL. On the other hand, in 2 and 4 stone-free patients (18% overall) who underwent ureteroscopy and ESWL, respectively, favorable radiographic features consisted of a short, wide but acutely angulated infundibulum with the infundibulopelvic angle less than 90 degrees, and infundibular length less than 3 cm. and width 5 mm. or greater. In contrast, in 4 and 6 patients (29% overall) who underwent ureteroscopy and ESWL, respectively, all 3 radiographic features were unfavorable with the infundibulopelvic angle less than 90 degrees, and infundibular length greater than 3 cm. and width less than 5 mm. In these cases the stone-free rate was 50 and 17% after ureteroscopy and ESWL, respectively. CONCLUSIONS: The 3 major radiographic features of the lower pole calix (infundibulopelvic angle, and infundibular length and width) can be easily measured on standard IVP using a ruler and protractor. Each factor individually has a statistically significant influence on stone clearance after ESWL. A wide infundibulopelvic angle or short infundibular length and broad infundibular width regardless of infundibulopelvic angle are significant favorable factors for stone clearance following ESWL. Conversely, these factors have a cumulatively negative effect on the stone clearance rate after ESWL when they are all unfavorable. In ureteroscopy spatial anatomy has less of a role in regard to stone clearance but it may have a negative impact when there is uniformly unfavorable anatomy.

Adult↗

Is there a simpler method for predicting lower pole stone clearance after shockwave lithotripsy than measuring infundibulopelvic angle?

BACKGROUND AND PURPOSE: Several anatomic factors influence the clearance of lower pole stones treated with shockwave lithotripsy (SWL). One of these is the infundibulopelvic angle, but its measurement is complex. METHODS: We proposed a more simple measure of caliceal dependence, the caliceal pelvic height (CPH), which we defined as the distance between a horizontal line from the lowermost point of the calix containing the stone to the highest point of the lower lip of the renal pelvis. RESULTS: In 62 patients who had SWL for solitary lower pole stones, a CPH < 15 mm was associated with a stone clearance rate of 92%, whereas with a CPH > or = 15 mm, the clearance rate was only 52% (p < 0.05). A majority (74%) of the patients with an infundibular width of > or = 5 mm were rendered stone free compared with 40% of those with a width of < 5 mm (p < 0.05). CONCLUSION: Measurement of the CPH, in conjunction with other anatomic factors, may more accurately predict the outcome of SWL in patients with lower pole stones.

Adult↗

Does tamsulosin enhance lower ureteral stone clearance with or without shock wave lithotripsy?

OBJECTIVES: To evaluate whether alpha1-blockers have any impact on stone clearance in patients with lower ureteral stones who underwent either shock wave lithotripsy (SWL) or were followed up with standard hydration, analgesics, and anti-inflammatory treatment. METHODS: A total of 78 patients (56 men and 22 women) who had lower ureteral stones located at the distal 5 cm of the ureter were divided into four groups. The first group consisted of 30 patients (38.5%) with stones less than 5 mm (range 3 to 5) who were randomly divided into two subgroups. Group 1 consisted of 15 patients (19.2%) who were followed up with oral hydration and diclofenac sodium. Group 2 consisted of 15 patients (19.2%) who received tamsulosin 0.4 mg daily in addition to the standard regimens. The second two groups consisted of 48 patients (61.5%) with stones greater than 5 mm (range 6 to 15) who underwent SWL. These patients were also randomly divided between those who did not (group 3, n = 24) and those who did (group 4, n = 24) receive tamsulosin 0.4 mg daily. All patients were re-evaluated with plain abdominal x-rays and helical computed tomography 15 days after the beginning of treatment. RESULTS: Of the 78 patients, 36 (46.2%) became stone free. The stone-free rate was 20%, 53.3%, 33.3%, and 70.8% for group 1, 2, 3, and 4, respectively. The best results were achieved in those who underwent SWL plus tamsulosin treatment (group 4). The differences between the stone-free rates for groups 3 versus 4 (P = 0.019) and the tamsulosin versus control groups (P = 0.0015) were statistically significant. CONCLUSIONS: The addition of tamsulosin to conventional treatment seemed beneficial in terms of stone clearance of lower ureteral stones, and this effect was more evident for larger stones, especially when combined with SWL.

Adrenergic alpha-1 Receptor Antagonists↗

Stone clearance in lower pole nephrolithiasis after extra corporeal shock wave lithotripsy - the controversy continues.

BACKGROUND: To determine factors influencing the clearance of fragments after extra-corporeal shock wave lithotripsy (ESWL) for lower pole calyceal (LPC) stones. METHODS: In the period between July 1998 and Oct 2001, 100 patients with isolated lower polar calyceal calculi or= 14 years, were included in the study. Intravenous urograms (IVU) were reviewed to define the LPC anatomy (width of the infundibulum and pelvicalyceal angle). Study end points i.e. stone free status; number of shock waves used and number of sessions were correlated with variables like LPC anatomy, body mass index and stone size. RESULTS: At three months follow up the clearance for stone size 90 degrees ) had stone clearance of 94 and 100% respectively. For the infundibular width of < 4 mm, the stone clearance was 93% were as for > 4 mm, it was 100%. For body mass index (BMI) less than and > 30 kg/m2, the stone clearance was 92 and 95% respectively. CONCLUSIONS: There is a trend towards more ESWL sessions and shock wave requirement in patients with acute pelvi-calyceal angle and narrow infundibulum but it is not statistically significant. Size (<or= 20 mm) and BMI has no relation with stone clearance. With modern lithotripter, stones up to 20 mm could primarily be treated by ESWL, irrespective of an un-favorable lower polar calyceal anatomy and body habitus.

Adolescent↗

Impact of lower pole renal anatomy on stone clearance after shock wave lithotripsy: fact or fiction?

PURPOSE: We determined whether there is a significant relationship between the spatial anatomy of the lower pole on preoperative excretory urography and stone fragment clearance after shock wave lithotripsy. MATERIALS AND METHODS: The anatomical factors affecting lower pole stone clearance after shock wave lithotripsy were evaluated retrospectively in 108 patients. Stone-free status was assessed by renal computerized tomography with or without renal ultrasound. The stone-free rate at 3 months was correlated with lower pole infundibular length and width in mm. as well as with the lower pole infundibulopelvic angle in degrees. The statistical significance of each lower pole anatomical factor as well as other stone, renal and treatment factors were correlated with the stone-free rate using the Mann-Whitney and chi-square tests. RESULTS: Three months after shock wave lithotripsy 79 patients (73.1%) were free of stones. Mean lower infundibular length plus or minus standard deviation was 20.9 +/- 6.56 mm., mean infundibular width was 5.65 +/- 2.34 mm. and the mean lower pole infundibulopelvic angle was 48.33 +/- 14.84 degrees. In 49 (45.4%) and 59 (54.6%) patients infundibular length was greater than 3 cm. and 3 cm. or less, respectively. Infundibular width was greater than 5 mm. and 5 mm. or less in 45 (41.7%) and 63 (58.3%) patients, respectively. No obtuse infundibulopelvic angles were noted. None of the 3 lower pole anatomical factors had any significant impact on the stone-free rate at 3 months. Renal morphology was the only factor significantly affecting the stone-free rate since stone clearance was significantly less in pyelonephritic kidneys (p = 0.0009). CONCLUSIONS: Differences in the intrarenal anatomy of the lower pole have no significant impact on stone clearance after shock wave lithotripsy. Further examination of the lower pole renal anatomy with a search for other contributing factors is still warranted.

Adolescent↗

Intensified ESWL of gallstones: dissociation of pulverisation, pain relief and stone-clearance.

BACKGROUND/AIMS: Recently, intensified shock wave lithotripsy for gallstone pulverisation and subsequent clearance without bile salt medication has been advocated. We report our first 44 patients treated by this regime: Patients with intact gallbladder function and symptomatic gallstones of any size, number and composition. METHODOLOGY: Forty-four consecutive patients who received intensified shock wave lithotripsy for gallstone pulverisation and clearance were included in this study. The patients all had intact gallbladder function and presented with symptomatic gallstones of any size, number and composition. RESULTS: Pulverisation was achieved in 75% of all cases (12 months), but only 34% were stone free. The proportion of patients with stone pulverisation compared to subsequent complete clearance was 93% versus 60% in small (</ = 20mm) solitary stones and 67% versus 15% in two or more stones. The pain intensity was markedly reduced within the first month of treatment, irrespective of complete pulverisation or definite stone clearance. CONCLUSIONS: The approach of stone pulverisation by multiple shockwave treatments is effective in solitary stones but does not achieve adequate stone clearance in multiple gallstones. Despite the low stone clearance rates in multiple stones, intensified ESWL used alone may be effective for these patients, if they are not eligible for surgery and the purpose of treatment is pain relief.

Cholelithiasis↗

Measurement of renal anatomy for prediction of lower-pole caliceal stone clearance: reproducibility of different parameters.

BACKGROUND AND PURPOSE: The architecture of the lower renal pole seems to have a considerable influence on caliceal stone clearance after different therapeutic modalities. The published data are partially inconsistent, and publications on reproducibility are completely lacking. The aim of this study was to evaluate the intraobserver and interobserver reproducibility of different measures of lower-calix anatomy. MATERIALS AND METHODS: We studied the intraobserver and interobserver reproducibility of parameters describing the lower-pole anatomy that are significant for treatment outcome. Forty renal units without urologic disease were analyzed by five independent urologists. Infundibular length (IL), infundibular width (IW), and lower infundibulopelvic angles (LIP) were measured by the Elbahnasy (LIP I), Keeley (LIP II), and Gupta (LIP III and LIP IV) methods. Statistical analysis of each parameter and investigator was performed. RESULTS: All LIP angles showed low interobserver correspondence: correlation coefficients (CC) did not exceed 0.44 (P < 0.05). Even the relatively clearly defined parameters IW and IL achieved CCs of only 0.63 and 0.49, respectively. The intraobserver correlation achieved better results: 0.73 (LIP I), 0.84 (LIP II), 0.73 (LIP III), 0.65 (LIP IV), 0.88 (IL), and 0.82 (IW). With the Elbahnasy method, almost all renal units were classified as favorable for stone persistence after shockwave lithotripsy. With the Keeley and Gupta methods, more than 50% of the kidneys were defined as having low clearance probability. CONCLUSIONS: Assessment of the chosen parameters is difficult and shows high interobserver variation. Inexperience in measuring the specific angles and low imaging quality can limit correct evaluation. The large number of kidneys with anatomy inappropriate for clearance of lower-pole stones may explain the poor outcome of shockwave treatment for stones in a lower calix. Prospective studies will determine the clinical value of anatomic assessments.

Humans↗

Lower pole ratio: a new and accurate predictor of lower pole stone clearance after shockwave lithotripsy?

BACKGROUND: Lower pole spatial anatomy is an important determinant of success after extracorporeal shockwave lithotripsy. In the present study, we determine whether there is a significant relationship between lower pole ratio (infundibular length : infundibular width) on preoperative intravenous urograms and stone fragment clearances after shockwave lithotripsy. METHODS: A total of 42 patients with isolated lower pole stones were retrospectively reviewed. Anatomical factors, such as infundibular length, width and infundibulopelvic angle were measured and the lower pole ratio was calculated on pretreatment intravenous urogram. Stone fragment clearance was assessed at three months with a plain abdominal X-ray. RESULTS: The overall three-month stone-free rate was 62%. Mean stone size +/- SD was 10 +/- 4.8 mm, mean infundibular length was 21.7 +/- 6.9 mm, mean infundibular width was 6.1 +/- 2.3 mm, mean infundibulopelvic angle was 62.1 +/- 30.1 degrees and mean lower pole ratio was 4.3 +/- 2.8. Stone-free status after shockwave lithotripsy was significantly related to infundibular length and width as well as to lower pole ratio, but not to infundibulo-pelvic angle. Infundibular length less than 30 mm, width greater than 5 mm and lower pole ratio less than 3.5 were noted to have an improved three-month stone-free rate (P = 0.049, 0.01 and <0.01, respectively). CONCLUSION: Caliceal anatomy is an important consideration for lower pole stone clearance after shockwave lithotripsy. The present study suggests that a lower pole ratio of less than 3.5, which considers both infundibular length and width, is a promising predictor for stone-free status.

Adult↗

Lower-pole caliceal stone clearance after shockwave lithotripsy, percutaneous nephrolithotomy, and flexible ureteroscopy: impact of radiographic spatial anatomy.

Spatial anatomy of the lower renal pole, as defined by the infundibulopelvic angle (LIP angle), infundibular length (IL), and infundibular width (IW), plays a significant role in the stone-free rate after shockwave lithotripsy. A wide LIP angle, a short IL, and a broad IW, individually or in combination, favor stone clearance, whereas a LIP <70 degrees, an IL >3 cm, or an IW < or =5 mm are individually unfavorable. When all three unfavorable factors or an unfavorable LIP and IL coexist, the post-SWL stone-free rate falls to 50% or less. Using these criteria, more than one fourth of our patients with a lower-pole calculus might have been better served by an initial percutaneous or perhaps ureteroscopic procedure, neither of which is significantly affected by the lower-pole spatial anatomy.

Adolescent↗

Impact of lower pole anatomy on stone clearance after shock wave lithotripsy.

This study retrospectively analyzed patients treated with shock wave ithotripsy (SWL) for lower calyceal stones, to determine the influence of the lower pole anatomy and stone size in predicting the clearance of fragments. Between June 2000 and March 2002, we reviewed excretory urography (IVU) of 59 patients with isolated lower pole stones treated with SWL. A total of 44 men and 15 women, with an age ranging between 23 and 78 years (mean, 55 years), were included in the study. The patients were divided into two groups, either a stone-free group or residual-stone group. After SWL, overall stone rate was 57.6%, and clearance for stones less than 10 mm in diameter was 64.5%, whereas clearance was 50% for stones between 10 and 20 mm in diameter. Intrarenal anatomy on IVU, such as infundibular width and infundibulopelvi-ureteric angle showed no significant difference between the stone-free and residual-stone groups. Our analysis showed that three significant variables were relevant to stone clearance: infundibular length, stone size and stone burden. We conclude that SWL is the best treatment for lower pole kidney stones 10 mm or less in diameter, showing lower complication and acceptable stone-free rates.

Adult↗