Kidney Stones Research Today is a free monthly online journal that collates and summarizes the latest research about Kidney Stones, including details on causes, symptoms, treatment, diagnosis of nephrolithiasis, calculi.

Observations on intrarenal geometry of the lower-caliceal system in relation to clearance of stone fragments after extracorporeal shockwave lithotripsy.

Leykamm L, Tiselius HG

Department of Urology, Karolinska University Hospital (Huddinge), Sweden.

PURPOSE: To study the intrarenal geometry of the lower-caliceal system in patients with and without residual fragments after extracorporeal shockwave lithotripsy (SWL) and to formulate a summarizing mathematical expression of relevant variables. PATIENTS AND METHOD: In a series of patients consecutively treated by SWL, we analyzed the geometric anatomy in 47 patients with (group R) and 47 without (group NR) residual fragments in long-term follow-up. A number of distances and angles previously described in the literature were measured, to which was added the distance between the stone-bearing calix and the vertex of the lower renal lip (CL) and the angle (delta) this line formed with a vertical line. RESULTS: There were significant differences between the groups in terms of infundibular length (P = 0.009), CL (P = 0.0020), and lower-caliceal height, CH (P = 0.0004). The calix width and the various angles did not differ significantly between the groups. The quotient CH/CL was used to calculate cos delta, and a summarizing expression (Index LC) was given the form CH(2)/CL which equals CH x cos delta. This index was significantly different in groups R and NR (P = 0.0036). Approximately 4% of the patients in group NR, compared with 28 percent in group R, had Index LC values >25. CONCLUSION: Index LC, as an expression of the geometry of the lower-caliceal system, might be useful for simple description of the lower-caliceal anatomy and supportive for decisions on the use of fragment clearance-facilitating procedures or the selection of a more invasive approach than SWL.

Published 24 April 2007 in J Endourol, 21(4): 386-92.
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