The difficult ureter: what is the incidence of pre-stenting?

INTRODUCTION: Difficulty may be encountered with retrograde access for rigid and flexible ureterorenoscopy (URS) due to anatomic abnormalities, a narrow ureteric lumen, tortuous ureteric path or previous instrumentation. Ureteric dilatation using a balloon or tapered dilator can occasionally fail and will usually lead to the placement of a ureteric stent. We present our experience and incidence of pre-stenting after failed standard access and dilatation techniques, the aim being to quote a figure for the patient at the time of consent. PATIENTS AND METHODS: Data were collected prospectively from a single surgeon at a regional tertiary referral stone unit. The outcomes of those patients pre-stented, for failed access, were recorded.
RESULTS: Between December 2007 and December 2008, a total of 119 patients underwent flexible and rigid URS. Mean patient age was 49 years (range, 19-86 years). Of these, 107 cases were undertaken for urolithiasis and 12 cases for diagnosis of upper tract malignancy. 12% (13/107) of cases were for pain and non-diagnostic imaging and 8.4% (9/107) of patients were pre-stented because of failed access, without complication, and subsequently had successful interval treatment. Of the remaining successful cases of confirmed urolithiasis, 33% (28/85) and 67% (56/85) were undertaken for ureteric and renal calculi, respectively. Stone clearance rates were 83% (19/23) and 75% (3/4) for lower pole renal calculi 5-10 mm and > 10 mm in size, respectively. The overall clearance rate for lower pole calculi was 81% (22/27). The ureteric stone clearance rate was 86% (24/28) rising to 92% (24/26) in those solitary stones less than 10 mm in size.
CONCLUSIONS: The incidence of ureteric pre-stenting in a tertiary referral unit was 8% and should be considered and indeed discussed with patients when obtaining pre-operative consent, especially for purely elective, non-urgent, upper tract cases. The alternative for these difficult, tight ureters is extensive balloon dilatation, with the risk of trauma and the potential for long-term stricture formation.