3582375050

Endourology and Stones

New Ureteral Access Sheaths: A Double 0 Standard

Shubha De, Carl Sarkissian, Fabio C. M. Torricelli, Robert Brown, and Manoj Monga

OBJECTIVE

MATERIALS AND METHODS

RESULTS

CONCLUSION

To invcsrigarc thc functional characrcristics of the traditional and new singlc-wire urcrcral access sheaih (UAS) configurations relating to msertion, positioning, tissue injury, and durability.

Four UAS wcrc tested: Navigator IID (11/13F, Boston Scientific), Rc-Tracc (10/12F, Coloplast), Flexor-Parallcl (P), and Flcxor-Regular (R; 9.5/11.5F, Cook Medical). UASs wcrc cvaluatcd for sharpness—(1) foil pcrforation, (2) tissue $kiving (advancing sheath/dilaror against fixcd foil or bologna model*); rigidity—(3) tip bending. (4) sheath buckhng; (5) lubricity (dynamie friction through bologna), (6) dilator rcmoval forcc, (7) kinking forccs (sidc wali comprcssivc forccs), and (8) radiopacity. New UASs wcrc uscd tor cach rrial. A morori:cd sliding srage was uscd, and continuous forcc mcasurcmcnts wcrc rccordcd with a Mark-10 digital forcc gauge.

The Navigator HD had the largest extemal diameter (13.02F). Re-Trace had the longest (51 mm) and most flexible tip (0.942 lb, P <.001). Flexor-R had the shortest (23.2 mm) and stiffest tip (7.48 Ib). The Cook tip pcrforation forccs wcrc highest (0.807 Ib), whcrcas thc sheath rcquircd thc most forcc (0.25 lb, P <.001) and causcd thc least damage (4.95 mm) when advanccd against tissue. Navigator HD had thc least frictional rcsistancc (0.14 lb, P <-001). The single-wire systems had the lowcst buckling forces (Navigator HD, 0.41 lb; Flexor-R, 0.827 lb; Flexor-P, 0.445 lb; Re-Trace, 1.014 Ib; P <.001) and the highest dilator rcmoval forccs comparcd with classic systems (Flcxor-P, 1.39 lb; Rc-Tracc, 1.9 lb; Navigator HD. 0.190 lb; Flexor-R, 0.194 lb; P <.001). The differences in kinking forces and radiopacity wcrc not signiiicant.

The Navigator HD was the most slippery and ngid sheath, whcrcas thc singlc-wirc systems had lower buckling forccs and required morę force to remove their dilators. Cook sheaths appeared the least traumatic. UROLOGY 85: 757—763, 2015. © 2015 Elscvicr Inc._

Ureteral access sheath (UAS) use during tlexible urcteroscopy providcs scveral advantagcs. including decreased intrarcnal pressurcs, improved irrigation flow rates,¹ better scope manipulation .ind longevity,' and decreased urothclial trauina. A typical UAS consists of a hollowed hydrophilic-coated polymer cylinder into which a tapered dilator is inserted. The tapered dilator acts as thc leading edge as it is back-loadcd ovcr a stiff guidewire and is ciHipled to the sheath. Undcr iluoroscopic guidance it is advanccd coaxially ovcr thc wite up to thc pcoximal ureter, and the inner dilator and working wire are removed. The sheath then remains, ptoviding an unobsmictcd passage from thc mcatus to thc pn>ximal ureter. Twoguidewires arc initially placeil using a dual-lumen catheter, with the UAS positioned ovcr a stiff working wirc (Amplatz Super Stiff guidewire; Boston Scientific, Natick, MA), leaving an extraluminal

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© 2015 Elsevier Inc.

Ali Rights Reserved safety wire. typically a Sensor (Boston Scientific) or Bentson (Cook Urological, Inc) guidewire.

A new UAS configuration combines thc traditional safety and working wire system into a single wire. Instead of using independent working and safety wires, the wirc used for placemenr becomes rhe extraluminal safety wire when thc dilator is rcmovcd. An cxit hole in the dilator 1-2 cm from thc tip allows the guidewire to be back-loaded through the apex of the tip and exit through a sidc hole in thc dilator distally (Fig 1). The wirc is co-axial only at the tip of rhe dilator and then courses par-allcl to thc sheath distally. When in position, thc dilator is rcmovcd, and a prrformcd pcrforation connccting thc entry and exit holes of the guidewire allows it to slip out. This lcavc$ thc guidewire in the cxtraluminal position, fimctioning as a safety wire for the remainder of the procedurę.

Out objective was to assess functional and safety charactcrisrics of contemporary UASs, looking specif-ically at 2 traditional coaxial sheaths, thc Flcxor-Rcgular (R) (Cook Medical, Bloomington, IN) and the Navigator HD (Boston Scientific), and two 2 configuration parallcl

http://dx.doi.Ofg/10.1016/j.urology.2014.07.009    757

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