Re: The Effects of Hyaluronic Acid and Carboxymethylcellulose in Preventing Recurrence of Urethral Stricture After Endoscopic Internal Urethrotomy: A Multicenter,Randomized Controlled,Single-Blinded Study

Dear Editor:

We read the article by Chung and colleagues with great interest. To treat urethral stricture, endoscopic internal urethrotomy (EIU) is widely performed but associated with a high stricture recurrence rate. The authors of this study investigated the effects of intraurethral use of hyaluronic acid (HA) and carboxymethylcellulose (CMC) on the recurrence of urethral stricture after EIU. As the article showed, HA/CMC instillation significantly decreased the incidence of stricture recurrence, and the technique seems to be a potential breakthrough in the management of this old urologic problem. We would like to add our comments regarding this study, however, with the hope to improve future studies on this issue.

First, as the authors stated, after instillation of HA/CMC, to block the bladder neck and keep HA/CMC between the urethral lumen and the Foley catheter, gauze was used to maintain the traction of the Foley catheter. The gauze was tied, and the Foley catheter was placed such that it faced upward and was fixed on the abdomen for 1 day. We believe this pressurized the catheter against the internal incision, which was performed at the 12 o'clock position. This could impact the efficacy of HA/CMC and epithelization of the internal incision. Thus, the technique for maintaining the traction of the Foley catheter should be improved.

The authors in this study used retrograde urethrography to measure the length of the urethral stricture or assess recurrence of stricture before and after the surgery, respectively. Actually, the evaluation of stricture length or recurrence with urethrography would be a bit subjective and arbitrary. This could be particularly relevant if the outcome assessor were not blinded as to the treatment. Considering the authors did not state that all outcomes were evaluated by a single surgeon, as well as the single-blinded study design, the potential bias is worth noticing.

Pansadoro and associates ¹ found that strictures could recur 7 to 8 years after urethrotomy. They suggested that a minimum follow-up of up to 5 years is needed to assess treatment results of urethral strictures. Twenty-four weeks is clearly not sufficient to confirm effects of HA/CMC instillation during EIU, and postoperation urethrography was even conducted only at 12 weeks (V2). Just as the authors indicated, a short follow-up period is one of the major limitations of the present study. Extended follow-up should be integrated into any study that assesses urethral strictures to verify whether the technique in question reduces or just postpones the urethral stricture recurrence.

In addition, discussion regarding the differences and advantages of this technique compared with others should be performed. Still, the authors presented an interesting study with a potentially effective adjuvant therapy of EIU preventing stricture recurrence.