Radiographic anatomical factors do not predict clearance of lower caliceal calculus by shock-wave lithotripsy.
OBJECTIVE
Use of shock-wave lithotripsy (SWL) for lower caliceal calculus is associated with a relatively high rate of residual fragments. Various radiographic anatomical factors of the lower calix predicting the outcome of lithotripsy have been described and have generated considerable discussion. We aimed to reassess the role of these factors in predicting clearance of lower caliceal stones by SWL.


METHODS
Between January 1998 and December 2001, 148 patients underwent SWL for solitary lower caliceal stones using a Dornier Compact S lithotripter. The infundibular length, infundibular width, caliceopelvic height and infundibulopelvic angle were measured. Success was defined as either complete clearance or clearance with insignificant residual fragments <4 mm in size at 3 months follow-up. The results were analysed using the chi2 test and logistic regression analysis.


RESULTS
Complete clearance was seen in 69% of cases and clearance with residual fragments <4 mm in size at 3 months was seen in 5%. The overall clearance rate at 3 months was 74%. Infundibular length, infundibular width, caliceopelvic height and stone size were not found to be statistically significant in predicting clearance. None of the patients had an infundibulopelvic angle of >90 degrees. Contrary to most previous studies, univariate and multivariate analysis revealed that an infundibulopelvic angle of <70 degrees was statistically significant in predicting clearance in the stone-free group.


CONCLUSIONS
The use of radiographic anatomical factors to predict clearance of lower caliceal stones following SWL is an attractive concept. However, based on this study, we feel that these factors do not merit the attention they have attracted. In routine practice, regardless of the radiological anatomy, SWL continues to be the initial treatment option, given its non-invasive nature and ease of administration.
Viswaroop
Bobby
B
Department of Urology, Christian Medical College, Vellore, India.
Devasia
Antony
A
Gnanaraj
Lionel
L
Chacko
Ninan
N
Kekre
Nitin
N
Gopalakrishnan
Ganesh
G
D000293:Adolescent; D000328:Adult; D000368:Aged; D005500:Follow-Up Studies; D006779:Hospitals, Public; D006801:Humans; D007194:India; D007669:Kidney Calculi / Q000000981:diagnostic imaging* / Q000628:therapy*; D007670:Kidney Calices / Q000000981:diagnostic imaging*; D008096:Lithotripsy; D008875:Middle Aged; D011237:Predictive Value of Tests; D011859:Radiography; D012189:Retrospective Studies; D016896:Treatment Outcome; D014513:Ureter / Q000000981:diagnostic imaging