The Singapore General Hospital early clinical experience with the 7.5F flexible ureterorenoscope. 
Reduced instrument size, increased flexibility, coupled with improved optics and larger working channels have enhanced the capabilities of the ureterorenoscope.  We present our initial experience with the new 7.5F flexible ureterorenoscope.  A total of 29 flexible ureterorenoscopies were performed from July 1995 to December 1997 by a single surgeon.  The indications for flexible ureterorenoscopy was therapeutic in 10 (34.5%) patients (all had urolithiasis) whilst it was diagnostic in 19 patients (65.5%).  For the diagnostic cohort, 9 (31.0%) patients had haematuria with radiological upper tract filling defect, 8 (27.6%) had radiological upper tract filling defect alone and 2 (6.9%) had ureteropelvic junction narrowing for evaluation.  Of the therapeutic cases, all 10 (100%) were stone free at 3 months.  Of the diagnostic cases, 12 (63.2%) had normal findings, 4 (21.1%) had urolithiasis and 3 (15.8%) had transitional cell carcinoma (TCC).  Of the 3 cases of TCC, one was managed endoscopically.  The smaller calibre and actively deflectable 7.5F flexible ureterorenoscopes facilitate various endoscopic procedures thus broadening the diagnostic and therapeutic scope of the ureterorenoscope.