Calyceal diverticula are believed to be congenital developmental abnormalities in the renal parenchyma that result in nonsecretory, urothelial-lined cavities that are filled with urine refluxing from an adjacent collecting system. The connection (i.e., neck) between such diverticula and the collecting system may range from being wide and short to long and narrow, with drainage impaired to a greater degree in the latter, resulting in infection and stone formation. This distinction also has implications for treatment of the narrowed neck. Diverticula are associated more commonly with the upper- and midcalyceal systems.

Although mostly asymptomatic, the indications for treatment of calyceal diverticula relate to the complications of recurrent infection, hematuria, and symptomatic calculi (reported incidence of between 10% and 50%<sup>11 Middleton A.W., Pfister R.C. Stone-containing pyelocalyceal diverticulum: Embryogenic, anatomic, radiologic, and clinical characteristics J Urol 1974 ;  111 : 2

Cliquez ici pour aller à la section Références</sup>). Current treatment options of the stone-bearing diverticula include shock wave lithotripsy (ESWL) as a noninvasive option and minimally invasive options, such as percutaneous, ureteroscopic, and laparoscopic approaches. Although technically simpler and potentially safer, stone-free rates with SWL have not been comparable with percutaneous nephrolithotripsy (PNL) methods (4%–58%<sup>10 Jones J.A., Lingeman J.E., Steidle C.P. The role of extracorporeal shock wave lithotripsy and percutaneous nephrostolithotomy in the management of pyelocaliceal diverticula J Urol 1991 ;  146 : 724

Cliquez ici pour aller à la section Références, 12 Psihramis K.E., Dretler S.P. Extracorporeal shock wave lithotripsy of caliceal diverticula calculi J Urol 1987 ;  138 : 707

Cliquez ici pour aller à la section Références</sup> versus >80%<sup>10 Jones J.A., Lingeman J.E., Steidle C.P. The role of extracorporeal shock wave lithotripsy and percutaneous nephrostolithotomy in the management of pyelocaliceal diverticula J Urol 1991 ;  146 : 724

Cliquez ici pour aller à la section Références</sup>). Shock wave lithotripsy, purely an energy source, also fails to address the primary problem of drainage of the diverticula, although Hsu and Streem<sup>9 Hsu T.H., Streem S.B. Metabolic abnormalities in patients with caliceal diverticular calculi J Urol 1998 ;  160 : 1640  [cross-ref]

Cliquez ici pour aller à la section Références</sup> have suggested that metabolic factors may play a greater role in stone prevention.

Dretler<sup>2 Dretler S.P. A new useful endourological classification on calyceal diverticula [abstract] J Endourol 1992 ;  6 (suppl) : F017

Cliquez ici pour aller à la section Références</sup> has proposed a classification of calyceal diverticula to assist in treatment decision making, but it has not been substantiated with long-term results and the issue of recurrence rates has not been addressed.

In terms of minimally invasive treatment options, PNL has the best results in terms of stone-free rates (> 90%), but it is technically demanding because there is usually little room to place the guidewire into the diverticulum, which makes tract dilatation more precarious. An anteriorly located diverticulum also necessitates a tract that traverses more renal parenchyma and increases the risk for significant hemorrhage. Laparoscopic approaches have been advocated with encouraging results<sup>5 Gluckman G.R., Stoller M., Irby P. Laparoscopic pyelocaliceal diverticula ablation J Endourol 1993 ;  7 : 315  [cross-ref]

Cliquez ici pour aller à la section Références, 8 Hoznek A., Herard A., Ogiez N. , et al. Symptomatic caliceal diverticula treated with extraperitoneal laparoscopic marsupialization, fulguration, and gelatin resorcinol formaldehyde glue obliteration J Urol 1998 ;  160 : 352  [cross-ref]

Cliquez ici pour aller à la section Références</sup> and may have a role in anterior-located diverticula with large stone burdens.

Although more effective than ESWL monotherapy, retrograde ureteroscopy is less invasive than percutaneous or laparoscopic approaches and can be performed as a day-case procedure. The authors believe that the retrograde, ureterorenoscopic method by way of retrograde intrarenal surgery (RIRS) has a definite niche in the management of calyceal diverticula and its related complications, such as stones.