Mieke Bus

104 Chapter 7 Discussion and future perspectives The work presented in this thesis demonstrated that optical diagnostics have the potential to improve the diagnosis of upper urinary tract urothelial carcinoma (UTUC). Technical improve- ments have been introduced in the design of ureterorenoscopy armamentarium over the past years. Modern (flexible) ureterorenoscopy resulted in improved visualization of UTUC. These developments in ureterorenoscopy have paved the way to allow endoscopic treat- ment of UTUC, starting in imperative indications and now expanding to elective indica- tions in patients with low-volume, low-grade, low-stage disease and a healthy contralateral kidney. (1, 2) To overcome the problem of under detecting, under grading and under staging of UTUC, new optical diagnostics are being evaluated in the upper urinary tract. Optimising Diagnosis of Upper Urinary Tract Urothelial Carcinoma One of the main challenges in endoscopic diagnosis of upper urinary tract urothelial carci- noma is the complicated anatomy and the small size of the upper urinary tract, resulting in high demands on the armamentarium and expertise of the urologist. Difficulties to reach the complete collecting system can result in an incomplete visual inspection. Complete arma- mentarium including flexible ureterorenoscopes and pliers for biopsies should be available for the urologist diagnosing and treating UTUC. To reach the renal pelvis, the instruments have to pass the urethra (and prostate) and are then inserted through the ureteral orifice into the ureter. The ureter is a tubular structure that is generally 22-30 cm in length and 2-4 mm in width. Anatomical angulation of the ureter may restrict the insertion of endoscopes, but also anatomical tapering of the ureter may provide difficulties. While inserting a ureterorenoscope in the ureter, one will come across three anatomical restrictions of the ureter; the ureterovesical junction, the crossing of the ureter with the iliac vessels and the ureteropelvic junction. By using a flexible ureterorenoscope the renal pelvis and the major calyces can usually easily be reached. To reach the lower pole calyx, the tip of the endoscope has to be capable to make a curve up to 180°. There is a huge anatomical variation in the number and location of the calyces and sometimes the necks of the calyces can be narrow, not allowing the endoscope to enter. Therefore, visual inspection should always be combined with fluoro- scopic imaging. The anatomy of the upper urinary tract demands great flexibility of endoscopes and instru- ments to inspect the complete collecting system. The limited diameter of the ureter, how- ever, considerably limits the size of ureterorenoscopes that can be used in the upper urinary tract. To visualize the complete upper urinary tract including pyelum, calyces and papillae, flexible ureterorenoscopy should be performed in combination with semi-rigid endoscopy. Modern flexible ureterorenoscopes have a tip diameter of 4.9 to 8.7 Fr, a shaft diameter of 7.1 to 10.9 Fr and a proximal diameter of 7.2 to 10.9 Fr and can reach a deflection of up to