Flexible ureteroscopy: Washington University experience with the 9.3F and 7.5F flexible ureteroscopes

Purpose: Recent advances in the design of flexible ureteroscopes have resulted in smaller caliber instruments. We review our experience with the smaller flexible ureteroscopes, and compare the efficacy and efficiency of the newer 7.5F to the standard 9.3F flexible instruments. Materials and Methods: Between January 1991 and 1995, 69 male and 41 female patients (mean age 57 years, range 16 to 91) underwent 116 retrograde flexible ureteroscopic procedures for a variety of diagnostic and therapeutic indications. A 9.3F ureteroscope (group 1) was used in 71 patients and a 7.5F instrument (group 2) was used in 39. Results: Patients in group 2 received sedation analgesia significantly more often than those in group 1 (56 versus 35%, p = 0.04). Active dilation of the ureteral orifice was required less often in group 2 (22.5%) than in group 1 (58%, p less than or equal to 0.05). The total success rate for stone management, and diagnosis and/or treatment of an upper urinary tract lesion was 98.3 and 100%, respectively, in group 1, and 90 and 100%, respectively, in group 2 (p = 0.17). Of the 71 patients in group 1, 17 (24%) were treated on an outpatient basis, compared to 14 of 39 (49%) in group 2 (p = 0.16). No intraoperative or postoperative major complications were encountered in either group. Group 2 required less postoperative analgesia (p = 0.05). No ureteral stricture occurred in either group at an average followup of 9.5 months postoperatively (range 2 to 35). Conclusions: For ureteral and renal pathological conditions the 7.5F ureteroscope is as effective as the 9.3F instrument diagnostically and therapeutically. The 7.5F ureteroscope usually can be used with sedation analgesia. Also, the smaller 7.5F ureteroscope is associated with less need for active ureteral dilation, minimal postoperative discomfort and a brief hospital stay.