To date, urologists are increasingly confronted with a group of patients that had a childhood cross-trigonal reimplantation of one or both ureters. With this technique, first described by Cohen in 1975, the ureter is tunnelled cross-trigonally within the posterior wall of the bladder to exit in the contralateral bladder half. This allows in almost all patients to achieve adequate submucosal length of the ureter. These patients are now coming into an age where they are prone to develop all sorts of urological pathologies necessitating a retrograde ureteric access . This is nicely illustrated by our case where a young man with such a reimplantation happens to develop hyperparathyroidism and urolithiasis. Not knowing about the reimplantation, several factors played together to obscure the picture for the surgeons. Firstly, the patient did not report his complete medical history, or perhaps, since this had happened in early childhood, he had simply forgotten about it. Secondly, the stone was lodged into the angulation of the ureter, therefore still projecting over the natural course of the right ureter. And finally, the stone blocked the ureter completely, thus not revealing any information about the course of the distal part of the ureter on IVU.
Cohen reimplantation has been reported as leading to difficulties in ureteric access [1–4]. A variety of approaches to solve the problem has been proposed such as a combination of cystoscopy and suprapubic percutaneous ureteric catheter insertion [2, 3], percutaneous transvesical ureteroscopy , and transurethrally by using a curved tip vascular catheter combined with an angled tip glide wire . Where the expertise is readily available, the ureter can also be accessed anterogradely and then later, if needed, retrogradely as in our case. We also found that once the ureter is marked, the insertion of an extra stiff guidewire will straighten the ureter and make access straightforward .
Patients with difficult ureteric access, abnormal anatomy, or those with known cross-trigonal ureteric reimplantations should be managed in a specialised endourology unit.