'Firm' versus 'soft' double pigtail ureteric stents: a randomised blind comparative trial.

It is generally considered that 'firm' double pigtail ureteric catheters, while easier to insert and less prone to migration, may cause more patient discomfort than the 'softer' variety of stent. Objective support for these perceptions is however lacking. The aim of this study was to compare firm and soft stents regarding their ease of insertion, positional stability, biocompatibility and patient tolerance. 155 patients were randomised to receive 'firm' (polyurethane, n = 78) or 'soft' (Sof-Flex, n = 77) stents. Ease and mode of insertion was recorded at time of initial placement. Positional stability, degree of bladder inflammation, stent encrustation and patient tolerance were recorded at the time of removal. Patient tolerance was assessed by symptom score in double-blind fashion. Results showed no significant difference in ease of insertion, positional stability, degree of bladder inflammation or stent encrustation between the two groups. There was a significantly higher incidence of dysuria, renal and suprapubic pain in the firm stent group. There was no significant difference in the incidence of urgency, frequency, nocturia or haematuria. Normal activity and return to work were reported in 67 and 45% of patients with soft and firm stents, respectively. The data indicates that patient tolerance appears to be related to the softness of the stent material.