Abstract
Introduction:
The vapor tunnel (VT) technology is a result of the pulse modulation during holmium laser emission: it consists of a single specific long pulse, using the minimum peak power in accordance with selected output settings. The first part of the pulse creates a vapor channel, whereas the remaining energy is discharged immediately after, passing straight through the previously created tunnel. This particular emission allows to reduce stone retropulsion. We herein present the outcomes of this new technology in the treatment of ureteral stones in an urgent setting.
Materials and Methods:
In total, 210 patients with ureteral stones, renal colic, and indication to undergo urgent stone lithotripsy, according to the inclusion criteria presented by Picozzi et al., 1 were randomly assigned to holmium laser lithotripsy with or without the VT technology (105 patients per group). The 100 W Cyber-Ho laser generator (Quanta System) was used for all cases performed with the VT; the 35 W Litho laser generator was used for all regular dusting mode (RDM) procedures. A 365 μm fiber was used in both groups. Energy and frequency settings were 1 J and 12 Hz in both groups. All procedures were performed by three experienced urologists. After the procedures, a ureteral stent was always positioned and removed 20 days later. We compared dusting time, total procedural time, and stone retropulsion, graded on a Likert scale from 0 (no retropulsion) to 3 (maximum retropulsion). We also compared postoperative ureteral lesions with the Posturetroscopic Lesion Scale (PULS), 2 the success rates of the two techniques based on stone-free rate at 1 month (defined as absence or presence of maximum 1 mm stone fragments at a computed tomography -scan) and postoperative ureteral strictures. The study was approved by our institutional review board and patients signed the informed consent.
Results:
The RDM and VT groups were comparable in terms of age and mean preoperative stone size (1.1 vs 1.0 cm, p > 0.05). The VT technology was associated with significantly lower (p > 0.05) dusting time (15.3 vs 9.7 minutes), total procedural time (37.2 vs 25.7 minutes), total delivered energy (19.9 vs 7.7 kJ), and retropulsion (Likert score 3 vs 0). Patients in the RDM group required stone fragments' retrieval with a Tipless Basket (Kobot Filter; RocaMed) and presented a higher rate of PULS-1 ureteral lesions than the VT group: 37 (35.2%) vs 8 (7.6%) patients p < 0.05. Whereas the VT setting allowed complete dusting of the stones. We registered six cases (5.7%) of postoperative ureteral strictures in the RDM group vs no cases in the VT group, p < 0.05. Stone-free rate at 1 month was comparable between the two groups (88.6 vs 93.4%, p < 0.05).
Conclusions:
The VT technology is associated with significantly lower dusting time and total procedural time, because of reduced retropulsion of the stone, which makes it more precise, quicker, and easier to perform. It also allows complete dusting, with no need for fragments' retrieval, reducing ureteral lesions, because of scratches on the ureteral wall. These features make VT an excellent setting option in an urgent setting, when the ureteral wall is more vulnerable.
No competing financial interests exist.
Runtime of video: 3 mins 49 secs
