RAMB - AGOSTO 2017

safety

guidewire

needed

for

retrograde

ureteroscopy

ssoc

ras

2017; 63(8):717-721

719

dilation and concomitant longstanding obstructive ure-

teral stones.

Two other groups reported independently their results

of semi-rigid and flexible URS for the treatment of stone

disease without an SGW.

5,9

Eandi et al.

reported no intra-

operative complications related to lack of a safety wire

over 322 semi-rigid and flexible URS performed for the

treatment of urolithiasis. Patel et al.

described their ex-

perience with flexible URS for the treatment of calyceal

and pelvic stones on 268 patients with the use of a work-

ing wire alone. In all, 20% of the patients needed ureteral

dilation, and 15% had a ureteral access sheath placed intra

operatively. The overall complication rate was 2.6%. There

were no intraoperative complications (no ureteral avulsions

or ureteral perforations). Overall, six patients had urinary

tract infection (Clavien grade II), two of whom needed

post procedure hospital admission and treatment with

intravenous antibiotics. One patient had a urinary reten-

tion (Clavien grade I). Access into the renal pelvis was

obtained in all patients except for one who had multiple

ureteral strictures necessitating a nephrostomy tube place-

ment with subsequent percutaneous nephrolithotomy.

However, the authors acknowledge that their study in-

cluded only patients with kidney stones and that, for the

treatment of concomitant ureteral stones associated with

significant edema, ureteral strictures, abnormal anatomy

or difficult visualization, a safety wire should be placed.

The only two available comparative studies in the

literature that studied the role of an SGW for semi-rigid

and flexible URS are depicted in Table 1. Moran and Brat-

slavsky

compared a single urologist’s experience with

flexible ureteroscopic laser lithotripsy without the use of

an SGW to a contemporary, large single-center’s experi-

ence with 11 treating urologists. A total of 340 flexible

ureteroscopies were performed over a single working wire

placed prior to laser lithotripsy, whereas 1,500 laser lith-

otripsies were done at a single center with an SGW in

place. Targeted stone destruction occurred in 98% of these

cases and the stone-free rates were lower in 96% (326/340)

for those that did not use an SGW. Failures in this cohort

were infrequent and occurred in seven patients with high

grade obstruction and/or impacted calculi. On the other

side, in the entire series of 1,500 patients the targeted

stone destruction occurred in 98% and stone-free rate was

96%, results identical to the technique without the safety

wire. There were no complications in the group without

a safety wire secondary to loss of upper tract access.

Ulvik et al.

compared the results of URS for the treat-

ment of ureteral stones at two different hospitals where

the SGWwas either routinely used or omitted. Both groups

had 500 patients each. Pretreatment stone status differed

in many aspects between groups. The hospital where an

SGW was routinely used treated more proximal stones,

more cases with obstruction and more urgent cases. As a

result, flexible endoscopes were employed in 39.8 and 4.4%

of the procedures in the group with an SGW and without

it, respectively (p<0.0005). Similarly, access sheaths were

used in 31.6% of the cases in the group with SGW compared

to only one case in the group without it (p<0.0005).

The reported success rates of passing the ureteroscope

through the ureteral orifice, the ability to access the ure-

teral stone and the ability to place a ureteral stent when

needed after the endoscopy were not significantly differ-

ent between the two groups of patients.

There was no

significant difference in the overall intraoperative com-

plication rates at the two hospitals. The overall stone-free

rates were 77.1% and 85.9% with and without the SGW,

respectively (p=0.001). However, according to the stone

location, the stone-free rates were 61.2 and 70.2% for up-

per (p=0.135), 72.6 and 81.1% for mid (p=0.305), and 89.8

and 93.9% for lower ureteral stones (p=0.102) with and

without SGW, respectively. A significant increase in the

number of patients (14 patients, 3.4%) was found to have

post endoscopic ureteral stenosis at the hospital where

the SGW was routinely used than at the hospital where

an SGW was omitted (six patients, 1.2%), p=0.039.

iscussion

The advantage of using an SGW is to ensure a prompt

stent placement in an event of a major ureteral perfora-

tion or bleeding precluding continuing URS.

3,13

However,

what we found on the literature is that the cumulative

evidence that endorse the routine use of an SGW during

URS is very weak (level of evidence grade C). It seems that

there is a belief that the routine use of an SGW may not

be necessary and may even be deleterious, mainly due to

the fact that working without a safety wire often facilitates

access to the kidney (less friction passing the ureteroscope),

scope manipulation (less torque to rotate the scope), and

makes it easier to laser and basket fragments.

5,9,12

Moreover,

many publications have described their successful experi-

ence with both semi-rigid and flexible URS for the treat-

ment of both ureteral and renal stones without the use

of an SGW.

5,6,9-12

The idea of historical longstanding dogma of “SGW

always in endourology” may have come from a time when

the ureteroscopes, lithotripsy equipment and disposable

materials were under development. Nowadays, small digital

flexible ureteroscopes with 270 degrees of deflection, small

laser fibers, hydrophilic ureteral access sheaths, hybrid guide-