Page 8 - CUA2018 Abstracts - Endourology

Poster session 4: Endourology

able at https://cua.guide/). In all cases, a 360 micron laser fiber was used, Methods: After informed consent, a confirmed negative urine culture,
typically set at 1 J and 10 Hz; the laser was activated as it was pushed and one–week pre–treatment with tamsulosin, four carefully selected
into the calyceal fornix and advanced until it exited the skin of the flank. PCNL patients underwent endoscopic–guided retrograde access in a
Results: In six of seven patients (86%), access via an upper pole posterior prone, split–leg position using the Lawson Catheter (Figs. 1, 2; available
calyx was achieved using the holmium laser–assisted endoscopic–guided at https://cua.guide/).
retrograde technique. In one patient, the laser tract was not dilated due Results: In all four patients, endoscopic–guided retrograde upper pole
to acute angulation; consequently, antegrade endoscopic– and fluoro- access with the Lawson catheter in the prone split–leg position was suc-
scopic–guided access was performed. Mean total fluoroscopy time in the cessful (Table 1; available at https://cua.guide/). A single complication
six successful cases was 32 seconds (range 5–64). There was one Clavien occurred (Clavein 3B) that required stent exchange due to stent occlusion
3a postoperative complication of a subcapsular hematoma and secondary from clot obstruction and urinoma formation with elevated creatinine of
tearing of an interpolar vessel remote from the site of access necessitating 5.1, however, with no change in hemoglobin or signs of bleeding. The
angioembolizaton and transfusion of two units of packed red blood cells. mean preoperative stone volume was 1840 mm (924–3038) with a den-
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Conclusions: Holmium laser–assisted endoscopic–guided retrograde sity of 872 Hounsfield units (400–1111). The mean ureteral injury PULS
access in a prone split–leg position appears to be feasible. Further work score was 0.75 (0–2). Fluoroscopy time was 162.3 seconds (51–283).
is needed in order to better refine the technique and determine the limita- The absolute stone volume reduction was 1826 mm (99%). Complete
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tions of this approach. stone–free rate by postoperative Day 1 computed tomography scan was
25%, and 100% for stones less than 4 mm.
UP–4.2 Conclusions: In this very limited initial experience, endoscopic–guided
retrograde upper pole access for PCNL can be established efficiently with
Shockwave lithotripsy for large renal calculi: Is prophylactic our modified Lawson technique in the prone split–leg position.
stenting beneficial?
Tadeusz Kroczak , Daniela Ghiculete , John Honey , Michael Ordon ,
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Jason Lee , Kenneth Pace 1 UP–4.4
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1 Division of Urology, Department of Surgery, St. Michael’s Hospital, Impact of percutaneous nephrolithotomy on renal function
University of Toronto, Toronto, ON, Canada Luke Reynolds , Daniela Ghiculete , Jason Lee , Monica Farcas , John
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Introduction: For selected patients, shockwave lithotripsy (SWL) is a mini- Honey , Michael Ordon , Kenneth Pace 1
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mally invasive treatment option for certain upper tract urinary calculi. It 1 Urology, St. Michael’s Hospital, University of Toronto, Toronto, ON,

is generally recommended that a ureteric stent be inserted prior to per- Canada; Urology, University Health Network, University of Toronto,
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forming SWL for large renal calculi in order to prevent post–procedure Toronto, ON, Canada
complications. We set out to determine if ureteral stenting prior to SWL Introduction: Percutaneous nephrolithotomy (PCNL) remains the gold
for large renal calculi affects treatment success and complication rates. standard surgical intervention for the treatment of large–volume renal
Methods: A matched retrospective cohort study was performed comparing stones, including staghorn calculi. Since it involves traversing the renal
stented and non–stented patients undergoing SWL for solitary large renal parenchyma with a tract that ranges in circumference from 16 F to 30 F,
calculi at our centre. Patients were matched according to stone size. Large there is always some degree of renal injury. We sought to examine the
calculi were defined as those with an area of equal to or greater than impact of PCNL on renal function and complications in patients with
200 mm and at least one diameter greater than 15 mm. We compared normal and reduced renal function.
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procedure outcomes and complications at two weeks and three months Methods: We retrospectively analyzed all consecutive tubeless PCNLs
between patients with and without a pre–SWL stent. performed at our institution between 2012 and 2017 that had a creatinine
Results: One hundred and sixty–eight patients (84 stented, 84 non– and estimated glomerular filtration rate (eGFR) measurement pre– and
stented matched controls) were identified. There was no differnece in post–procedure and a followup visit at our centre. Data was collected
stone size size between stented patients and matched controls (261.1 on patient and stone characteristics, and patients were divided in two
mm vs. 260.8 mm ). No significant differences were noted in patients groups based on their preoperative eGFR (Group 1: eGFR <50 ml/min,
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undergoing SWL with or without a stent with respect to presentation to Group 2: eGFR ≥50 ml/min).
the emergency department post–SWL treatment (13.1% vs. 21.4% NS) Results: A total of 220 patients were included in the study: 25 (11.4%)
and rate of Steinstrasse (10.7% vs. 14.3% NS). Ten patients who were not in Group 1 (mean creatinine 168.4 µmol/L±59.2) and 195 (88.6%) in
pre–stented (11.9%) eventually required ureteric stenting after SWL. After Group 2 (mean creatinine 80.5 µmol/L±19.5). There were no differences
two weeks, single–treatment SWL success rates were similar for patients in gender, stone side, stone area and composition, but patients in Group
without a stent compared to those with a stent. No difference in success 1 were older (66.6 years±10.8 vs. 54.1±13.3; p≤0.001) and had a lower
rate was demonstrated after three or less treatments for patients in both body mass index (BMI) (26.4±3.7 vs. 29.0±5.9; p=0.031). Patients with
groups (78.6% stent vs. 70.2% no stent NS). eGFR <50 were more likely to have a preoperative nephrostomy tube
Conclusions: In selected patients, pre–SWL stenting for large, solitary (NT) or stent (32% vs. 10.3%; p=0.002) and more likely to require mul-
renal calculi may not improve stone–free rates, nor reduce Steinstrasse tiple tracts (16% vs. 3.6%; p=0.007). Patients with eGFR <50 did not
rates. For patients initially receiving SWL without a stent, few patients have more postoperative complications (12% vs. 15.9%; NS). Creatinine
required ureteric stenting after SWL due to complications. values changed only marginally postoperatively, but less so in patients
with preoperative eGFR<50 (mean increase in creatinine 1.8%±20.1 vs.
UP–4.3 –10.1%±19.2; p=0.043).
Conclusions: Patients with baseline reduced renal function often have
Lawson retrograde endoscopic–guided nephrostomy access for more complex and obstructing stone disease, requiring more preoperative
percutaneous nephrolithotomy in prone split–leg position drainage tubes and greater need for multiple tracts. Despite this, PCNL
Egor Parkhomenko , William Kim , Cyrus Lin , Zachary Valley , Zhamshid can be performed safely, with no increase in complications and minimal
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Okhunov , Roshan Patel , Kamaljot Kaler 1 negative impact on renal function acutely.
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1 Urology, University of California, Irvine, Orange, CA, United States
Introduction: Percutaneous access for percutaneous nephrolithotomy
(PCNL) is presently obtained by a minority of urologists. Previous reports
have shown retrograde PCNL is easier to learn, however, only in the
modified supine position. Herein, we describe our initial experience with
Lawson retrograde endoscopic–guided percutaneous access in the prone
split–leg position.
S88 CUAJ • June 2018 • Volume 12(6Suppl2)