The most common direction of mound shift is medially and caudally towards the bladder neck. Studies have shown that autologous chondrocytes, PTFE, and dextranomer/hyaluronic acid all shift toward the bladder neck if shifting occurs. Diamond et al describe distally shifted mound in 75 % of their technical failures. 10 The mechanism of shifting is thought to be due to the bladder contraction creating pressure gradient toward the bladder neck. Capozza et al found an association between mound shift and those patients with voiding dysfunction symptoms. Twenty-five of 27 patients with treatment failure had voiding dysfunction symptoms including frequency, urgency, and incontinence. 11
10. Diamond DA , Caldamone AA , Bauer SB , Retik AB . Mechanisms of failure of endoscopic treatment of vesicoureteral reflux based on endoscopic anatomy. J Urol 2003 ; 17 : 1556 – 8 ; discussion 1559 .
11. Capozza N , Lais A , Matarazzo E et al. Influence of voiding dysfunction on the outcome of endoscopic treatment for vesicoureteral reflux. J Urol 2002 ; 168 : 1695 – 8 .