Prof. Dr. Hesham Abd Elhamid Badawy Prof. Dr. Hosni Khairy Salem Prof. Dr. Mohamed Nabil El ...

20 Pages·2015·0.9 MB·English

The Role of Non-Enhanced Spiral Computed
Tomography (NESCT) in Predicting the
Outcome of Extracorporeal Shock Wave
Lithotripsy (ESWL) on Renal Stones
Thesis
Submitted for fulfillment of master degree in urology
By
Hany Mahmoud Selim
M.B., B.Ch.

Under Supervision of
Prof. Dr. Hesham Abd Elhamid Badawy
Professor of Urology
Faculty of Medicine – Cairo University
Prof. Dr. Hosni Khairy Salem
Ass. Professor of Urology
Faculty of Medicine – Cairo University
Prof. Dr. Mohamed Nabil El-Ghoneimy
Ass. Professor of Urology
Faculty of Medicine – Cairo University

2012
Acknowledgement
Acknowledgment
First and foremost thanks are to ALLAH, the most
beneficent and merciful.
I would like to thank Prof. Dr. Hesham Abd Elhamid Badawy
Prof. of Urology, Faculty of medicine, Cairo University who
put the idea for this thesis. I will remain indebted to his
sincere and father like encouragement and affiliation, he will
remain a model of wisdom and patience to me.
I would like to express my thanks to Ass. Prof. Dr. Hosni
Khairy Salem Ass. Prof. of Urology, Faculty of medicine, Cairo
University for continuous help, valuable discussion, advice
and encouragement. This work would not be of value without
his efforts.
I feel great pleasure to express my deep gratitude and
appreciation to. Ass. Prof. Dr. Mohamed Nabil El-Ghoneimy

Ass. Prof. of Urology, Faculty of medicine, Cairo University for
supervising the work, valuable criticism and continuous
guidance.
I would like to express my deep thanks to all patients who
are the subject of this study.
Finally, thanks to my parents, my dear wife and daughter for
their continuous support, care and love.
Hany Mahmoud Selim
I
List of Contents

List of Contents
Acknoledgement .................................................................................. I
List of Contents ................................................................................. II
List of Figures ................................................................................. III
List of Tables ....................................................................................IV
List of Abbreviations ......................................................................... v
Aim of The Work .............................................................................. 1
Introduction ...................................................................................... 2
Radiological anatomy of Tthe Upper Urinary Tract ....................... 4
Stone Formation ............................................................................... 12
Imaging of Renal Stones .................................................................. 20
Management of Upper Urinary Tract Stones ................................. 36
ESWL ............................................................................................... 41
Patients And Methods ...................................................................... 57
Results............................................................................................... 63
Discussion ......................................................................................... 75
Conclusions ...................................................................................... 85
Summary .......................................................................................... 86
References……………………………………………………………89
II
List of Figures

List of Figures

Figure 1: Left kidney viewed from above............. ................................................ 5
Figure 2:Left kidney calyces ................................................................................... 6
Figure 3:Methods of measurment of infundibulopelvic angle .......................... 9
Figure 4: States of saturation. ............................................................................... 12
Figure 5: Plain abdominal radiograph. ................................................................ 22
Figure 6: Intravenous pyelography. ..................................................................... 25
Figure 7: Ultrasound image ................................................................................... 27
Figure 8: Mean HU value of Ca oxalate, Ca phosphate & Uric a. stones. ... 31
Figure 9: Relation between mean HU and no. of ESWL sessions ................. 31
Figure 10: Basic design of ESWL. ...................................................................... 42
Figure 11: Principles of ESWL ............................................................................ 43
Figure 12: Mechanism of stone comminution ................................................... 45
Figure 13: Electrohydraulic shockwave generator............................................ 46
Figure 14: Piezoelectric shockwave generator ................................................. 47
Figure 15: Electromagnetic shockwave generator ........................................... 48
Figure 16: Methods of shockwaves focusing ..................................................... 49
FIGURE 17: NCCT SHOWING RIGHT RENAL PELVIC STONE…………………….59
Figure 18: ESWL Unit...............................................................................................60
Figure 19: Dornier MedTech lithotripter………………………………….…….61

Figure 20: Graph of success and failure…………………………………67
Figure 21: Graph showing the success rate percentage in the 3 groups.68
Figure 22: Graph showing results in relation to sex..................................69
Figure 23: Graph showing results in relation to laterality.......................70
Figure 24: Graph showing results in relation to stone site........................71
Figure 25 : Graph showing results in relation to stone type.....................72
III
List of Tables

LIST OF TABLES
Table 1: Medical methods for prevention of urinary stone.....................37
Table 2: Sex of the patients.....................................................................63
Table 3: Laterality of the stones..............................................................63
Table 4:Number of the stones..................................................................64
Table 5:Fresh and recurrent cases............................................................64
Table 6: Presence and degree of backpressure........................................64
Table 7: Site of the stones........................................................................65
Table 8: Type of the stones……………………………………………….65
Table 9: Descriptive statistics…………………………………………….66
Table 10: Results……………………………………………………..…..66
Table 11: Results in the 3 groups …………………………………….....67
Table 12: Univariate analysis for categorical variables ...........................68
Table 13: Univariate analysis of sex in relation to results........................69
Table 14: Univariate analysis of stone side in relation to results..............70
Table 15: Univariate analysis of stone site in relation to results...............71
Table 16: Univariate analysis of stone type in relation to results..............72
Table 17: Multivariate analysis for variables predicting failure of ESWL.73

IV
List of Tables

List of Abbreviations
Abbrev. Meaning
BMI Body mass index
CPH calyceal pelvic height
CR computed radiographs
DR digital radiographs
ESWL Extracorporeal Shock Wave Lithotripsy
HCT Helical computed tomography
HU Hounsfield Unit
IL infundibular length
IVP Intra Venous Pyelography
IW infundibular width
KUB Kidney ureter and bladder
LIP angle Lower pole infundibulopelvic angle
MRI Magnetic resonant imaging
NESCT Non Enhanced Spiral Computed Tomography
PCNL Percutaneous nephrolithotomy
ROI Region of interest
SS Super saturation
SW Shock waves
URS Ureteroscope
US Ultrasound

V
Introduction

Introduction
Patients with urolithiasis constitute an important part of everyday
urological practice . The optimal clinical management of this disease
requires knowledge of the diagnostic procedures , the rational treatment
of acute stone colic , stone expulsive treatment and the modern principles
of stone removal (Tiselius HG et al, 2001) .

The clinical introduction of ESWL during the early 1980s dramatically
changed the management of patients with urinary tract stones. For more
than 20 years since the worldwide dissemination of this technology, the
development of new lithotripters, modified indications and principles for
treatment, have changed completely the way in which patients with renal
stones are treated. Modern lithotripters are smaller and, in the vast
majority of cases, part of uroradiological tables allowing the application
of not only ESWL, but also of all other diagnostic and ancillary
procedures associated with the ESWL treatment (Miller NL. et al, 2007)

Accumulated experience has clearly shown that, in addition to the
efficacy of the lithotripter, the success rate of ESWL depends on the size
(volume), number, location and hardness of the concrements as well as on
the habitus of the patient and the experience of the operator (Logarakis
NF. et al, 2000).

Renal stones requires a reliable imaging technique . In case of an acute
stone colic, excretory urography (intravenous pyelography, IVP) has been
established as a gold standard diagnostic work-up of all patients with
symptoms of urinary tract stones. During recent years, unenhanced
helical computed tomography (CT) examinations have been introduced as
a quick and contrast-free alternative (Kobayashi T. et al, 2003).

The role of helical CT in the evaluation of stone patients has greatly
expanded in the last decade, and helical CT has become the radiologic
tool of choice in the assessment and treatment of patients with urinary
tract calculi, with up to 95% sensitivity, 98% specificity, and 97%
accuracy for the detection of urolithiasis (Smith RC et al,1999).
2
Introduction

New predictors of ESWL success are being identified with data provided
by non enhanced spiral computerized tomography (NESCT). Stone
attenuation has been identified as a potential predictor of ESWL success
(Gupta NP. et al,2005).

In addition, the attenuation value of calculi on computed tomography,
measured in Hounsfield units (HUs), was also studied to determine its
ability to predict the stone free rate after ESWL(Pareek G. et al, 2003).

The ability to predict stone fragility is of great interest to urologists, as
lithotripsy could be avoided in patients with shock-wave resistant stones.
Stones composed of a greater amount of calcium are harder and denser.
These stones create more X-ray attenuation, and are therefore associated
with a higher CT number or Hounsfield unit (HU). Uric acid and cystine
stones create relatively less X-ray attenuation compared with stones
composed of other materials, with attenuation coefficients ranging from
100 to 300 HU. Stones that contain significant calcium are often
associated with CT numbers of 600 HU or greater, occasionally
exceeding 1000 HU. Several studies have assessed stone density based on
CT attenuation coefficients and have suggested that denser stones are
more resistant to shock wave, particularly when CT numbers are greater
than 1000 HU. However, stone density characterization is currently more
accurate in vitro than in vivo (Motley G. et al, 2001).

3
Anatomy of the upper urinary tract

RENAL ANATOMY

Kidney Position and External Relationships

The kidneys lie in the retroperitoneum on top of the quadratus lumborum
and psoas muscles. Each kidney has a thin walled fibrous capsule that is
intimately adherent to the parenchyma, which in turn is surrounded by
perirenal fat. The perirenal fat is contained by Gerota’s fascia, which in
turn is surrounded by another layer of fat (i.e., the pararenal fat).

Posteriorly, the superior pole of each kidney rests against the diaphragm
and the tips of the 11th and 12th ribs. Deep to this, the underlying pleura
attaches to the 11th rib, which must be considered when a superior pole
percutaneous approach is planned, especially on the left where the kidney
lies higher in the retroperitoneum. The adrenal glands rest on top of the
kidneys medially against the cava on the right and aorta on the left.

The anterior surface of the right kidney is associated with the liver
superiorly, the curve of the duodenum over the mid portion and the
ascending colon inferior and medially. On the right side, the colon often
covers the lower half of the kidney medially. The anterior surface of the
upper pole of the left kidney is covered by the spleen superiorly and just
the tail of the pancreas medially as well as by, the splenic flexure of the
colon; the anteromedial surface of the entire left kidney is covered by the
descending colon. A retrorenal colon can be seen on either side in 1–10%
of percutaneous cases depending on patient positioning; it is more
common when the patient is in the prone position. However, this
condition is usually limited to patients with a markedly redundant colon
or patients with a horseshoe kidney (Sampaio FJB. 1996).

Usually the retrorenal colon covers only the lateral most portion or upper
pole of the kidney. For anatomic purposes, the kidney can be divided into
anterior and posterior segments. The plane of division for these segments
rests 30–50° posterior to the frontal plane of division for the body as a
whole owing to the rotation of the renal axis anteriorly by the psoas major
muscle (Fig. 1) (Kaye KW. 1984).

4
Anatomy of the upper urinary tract

Figure (1): Left kidney viewed from above showing anterior calyces projecting 70°
and posterior calyces 20° from the frontal plane of the kidney, as in a classic Brodel-
type kidney

The psoas muscle also defines the axis of the kidneys in the longitudinal
plane so that the upper pole is medial and posterior whereas the lower
pole is more lateral and anterior.

As such, the distance from skin to collecting system is shortest at the
upper pole and greatest at the lower pole of the kidney.

Internal Architecture of the Kidney and Collecting System

The glomeruli, proximal tubules, and distal convoluted tubules rest within
the renal cortex, which is the outer most layer of the renal parenchyma.
The loops of Henle and collecting ducts rest within the renal pyramids,
which together comprise the medulla of renal parenchyma and rest within
the center of the kidney.

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