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Файл:Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_1110_Библиотеки_им_академика_М_И_Перельмана
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Contents XI
VII.2. Manometric and Myographic Evaluation of the Anal
Sphincters Morphology and Function ....................................................... 265
C. Ratto, G.A. Santoro
VII.3. What Studies do we Really Need in the Treatment
of Benign Anorectal Diseases? .................................................................... 281
B. Cola, D. Cuicchi, R. Lombardi, P.F. Almerigi
Invited Commentary: A. Shafik ................................................................................. 305
SECTION VIII
Treatment Options for Fecal Incontinence .............................................................. 319
VIII.1. Introduction .................................................................................................. 321
G.A. Santoro, G. Di Falco
VIII.2. Surgical Treatment of Fecal Incontinence ................................................. 327
L. Zorcolo, D.C.C. Bartolo
VIII.3. New Treatment Options for Fecal Incontinence:
Radio-Frequency Delivery and Bulking Agents ........................................ 343
M. Trompetto, C. Pastore,A. Realis Luc
Invited Commentary: S.D.Wexner ............................................................................ 349
VIII.4. Neuromodulation for Fecal Incontinence .................................................. 355
C. Ratto, D.F. Altomare
Invited Commentary: K.E. Matzel ............................................................................. 367
VIII.5. Incontinence: Biofeedback and Other Nonoperative Modalities ............ 371
G. Bazzocchi, B. Salvioli
Invited Commentary: M. Camilleri ........................................................................... 383
SECTION IX
Treatment Options for Anal Fistulas ........................................................................ 387
T.L. Hull
Invited Commentary: S.D.Wexner ............................................................................ 399
SECTION X
Current Concepts in Management of Outlet Obstruction ..................................... 401
A.Infantino,R.Bellomo,F.Galanti,L.Pisegna Cerone
Invited Commentary: U. Karlbom, L.Påhlman ....................................................... 413
SUBJECT INDEX ........................................................................................................ 415
Contributors
PIER FRANCESCO ALMERIGI, M.D.
Department of Surgery
and Anaesthesiology
University of Bologna
S. Orsola-Malpighi Hospital
Bologna, Italy
ONATO F. A LTOMARE, M.D.
D
Associate Professor of Surgery
Head of Coloproctological Unit
Department of Emergency and Organ
Transplantation, General Surgery and
Liver Transplantation Unit
University of Bari
Bari, Italy
AVID C.C. BARTOLO, M.S., F.R.C.S.
D
Consultant Colorectal Surgeon
Colorectal Unit
Western General Hospital
Edinburgh, Scotland,United Kingdom
ABRIELE BAZZOCCHI, M.D.
G
Chief, Rehabilitation for Visceral
Disorders Unit
Montecatone Rehabilitation Institute
University of Bologna
Imola, Italy
ARC BEER-GABEL, M.D.
M
Director of the Pelvic Floor Unit
Consultant Gastroenterologist
Tel Hashomer Hospital
Tel-Aviv, Israel
EERARD L. BEETS, M.D., PH.D.
G
Department of Surgery
University Hospital Maastricht
Maastricht, The Netherlands
REGINA G.H. BEETS-TAN, M.D., PH.D.
Department of Radiology
University Hospital Maastricht
Maastricht, The Netherlands
OBERTO BELLOMO, M.D.
R
Department of Surgery
Ospedale “S. Maria dei Battuti”
S.Vito al Tagliamento
Pordenone, Italy
ICOLAE BOLOG, M.D.
N
Institute of Diagnostic Radiology
University Hospital
Zürich, Switzerland
ICHAEL CAMILLERI, M.D.
M
Clinical Enteric Neuroscience
Translational and Epidemiological
Research (C.E.N.T.E.R.) Group
Mayo Clinic College of Medicine
Rochester,Minnesota, United States
RUNO COLA, M.D., F.A.C.S.
B
President of the European
Council of Coloproctology
Chairman, Department of Surgery and
Anaesthesiology
University of Bologna
S. Orsola-Malpighi Hospital
Bologna, Italy
AJANA CUICCHI, M.D.
D
Department of Surgery
and Anaesthesiology
University of Bologna
S. Orsola-Malpighi Hospital
Bologna, Italy
XIV Contributors
RICHELLE J.F. FELT-BERSMA, M.D.,PH.D.
Department of Gastroenterology
and Hepatology
VU University Medical Center
Amsterdam, The Netherlands
JØRN FORTLING
B
Engineer
B-K Medical
Herlev, Denmark
RANCO GALANTI, M.D.
F
Department of Surgery
Ospedale “S. Maria dei Battuti”
S.Vito al Tagliamento
Pordenone, Italy
IUSEPPE GIZZI, M.D.
G
Associate Professor
Department of Medicine and
Gastroenterology
University of Bologna
S. Orsola-Malpighi Hospital
Bologna, Italy
TEVE HALLIGAN,M.B., B.S., M.D.,
S
F.R.C.P., F.R.C.R.
Professor of Gastrointestinal Radiology
Department of Specialist Radiology
University College Hospital
London, United Kingdom
RACY L. HULL, M.D.
T
Head, Section of Anal Physiology
and Ultrasound
Department of Colorectal Surgery
The Cleveland Clinic Foundation
Cleveland, Ohio, United States
ICHAEL HÜNERBEIN, M.D.,PH.D.
M
Department of Surgery and Surgical
Oncology
Charité University Hospital
Campus Berlin Buch and Helios
Hospital
Berlin, Germany
LDO INFANTINO, M.D.
A
Chief, Department of Surgery
Ospedale “S. Maria dei Battuti”
S.Vito al Tagliamento
Pordenone, Italy
RBAN KARLBOM, M.D., PH.D.
U
Associate Professor
Department of Surgery
University Hospital
Uppsala, Sweden
ONATHAN B. KRUSKA L, M.D., PH.D.
J
Chief, Abdominal Imaging
Beth Israel Deaconess
Medical Center
Associate Professor of Radiology
Harvard Medical School
Boston, Massachussets, United States
AX J. LAHAYE, M.D.
M
Department of Radiology
Department of Surgery
University Hospital Maastricht
Maastricht, The Netherlands
OUTER H. LAMERS, M.D., PH.D.
W
Department of Anatomy
& Embryology
University Hospital Maastricht
Maastricht, The Netherlands
AFFAELE LOMBARDI, M.D.
R
Department of Surgery
and Anaesthesiology
University of Bologna
S. Orsola-Malpighi Hospital
Bologna, Italy
ORUT MARINCEK, M.D.
B
Professor of Radiology
Chairman, Institute of Diagnostic
Radiology
University Hospital
Zürich, Switzerland
LAUS E. MATZEL, M.D.
K
Chirurgische Klinik
mit Poliklinik
FAU Erlangen-Nurnberg
Erlangen, Germany
ARS PÅHLMAN, M.D.,PH.D., F.R.C.S.,
L
F.R.C.S. (G
LASG)
Professor of Surgery
Department of Surgery
University Hospital
Uppsala, Sweden
Contributors XV
CLAUDIO PASTORE, M.D.
Coloproctology Service,
Department of Surgery
Regional Hospital
Tr ev i s o, I ta l y
UCIANO PELLEGRINI, M.D.
L
Division of Gastroenterology
M.F. Toniolo Hospital
Bologna, Italy
IA PISEGNA CERONE, M.D.
L
Department of Surgery
Ospedale “S. Maria dei Battuti”
S.Vito al Tagliamento
Pordenone, Italy
ARLO RAT TO , M.D.
C
Department of Clinica Chirurgica
Catholic University
Rome, Italy
LBERTO REALIS LUC, M.D.
A
Colorectal Unit
Colorectal Eporediensis Center
Policlinico of Monza
Monza, Italy
EATRICE SALVIOLI, M.D., PH.D.
B
Department of Internal Medicine
University of Bologna
S. Orsola-Malpighi Hospital
Bologna, Italy
HMED SHAFIK, M.D., PH.D.
A
Professor and Chairman
Department of Surgery
and Experimental Research,
Faculty of Medicine
Cairo University
Cairo, Egypt
AAP STOKER,M.D., PH.D.
J
Professor of Radiology
Department of Radiology
Academic Medical Center
University of Amsterdam
Amsterdam, The Netherlands
NGELO STUTO, M.D.
A
Department of Surgery
S.M.A. Hospital
Pordenone, Italy
STUART A. TAY L O R , M.D.,M.R.C.P., F.R.C.R.
Consultant Radiologist and Honorary
Senior Lecturer
Department of Imaging
University College Hospital
London, United Kingdom
AAIKE P. T ERRA, M.D.
M
Department of Radiology
Academic Medical Center
University of Amsterdam
Amsterdam, The Netherlands
OE J. TJANDRA, M.B.B.S., M.D.,F.R.A.C.S.,
J
F.R.C.S., F.R.C.P.S., F.A.S.C.R.S
Associate Professor of Surgery
Department of Colorectal Surgery
Epworth and Royal Melbourne Hospital
University of Melbourne
Melbourne,Victoria, Australia
ARIO TROMPETTO, M.D.
M
Colorectal Unit
Colorectal Eporediensis Center
Policlinico of Monza
Monza, Italy
OMINIK WEISHAUPT, M.D.
D
Institute of Diagnostic Radiology
University Hospital
Zürich, Switzerland
TEVEN D. WEXNER, F.A.C.S., F.R.C.S.,
S
F.R.C.S. (E
D)
Chairman, Department of Colorectal
Surgery
Cleveland Clinic Florida
Weston, Florida, United States
NDREW ZBAR, MD, FRCS (ED), FRCS
A
EN), FRACS, FCCS
(G
Professor of Surgery
School of Clinical Medicine
and Research
University of the West Indies
Cave Hill Campus
St. Michael, Barbados
UIGI ZORCOLO, M.D.
L
Assistant Professor
Colorectal Unit
University of Cagliari
Cagliari, Italy
SECTION I
Fundamental Principles
of Ultrasound Imaging
Fundamental Principles
of Ultrasound Imaging
G.A. Santoro
In examinations using external energy sources
such as X-rays, ultrasound, and injected radioactive substances, the information contained in the
images is produced by the interaction between the
energy and the organ under examination. This
interaction can be visualized in two different
ways: an image may be formed by the energy
which manages to pass through the organ or its
parts, or the energy reflected or scattered from
portions of the structure under examination may
be transferred into images. The two techniques
are respectively termed visualization by transmission and visualization by reflection. In the visualization by transmission technique, the energy is
propagated through the object, i.e., the biological
tissues; the energy which is not absorbed, scattered, or reflected by the tissues is visualized.
Traditional radiology makes use of this technique.
The visualization by reflection method uses the
energy which has been scattered back from or
reflected by the tissues. Diagnostic ultrasound
currently uses the technique of formation of
images by reflection.
Nature of Ultrasound
The term ultrasound describes the general form
of mechanical energy emitted at a frequency
above the limit of human audibility. The maximum frequency audible to humans is in the range
of 16–20,000 cycles per second, called Hertz (Hz),
whereas in diagnostic applications frequencies in
the 2.5–20 MHz (megahertz = million cycles per
second) range are used, corresponding to wavelengths of 1–0.1 mm in tissue.
Ultrasonic Transducer
The ultrasonic energy required to form an image
must be supplied from an external source which
can be continuous or impulsive. The formation of
images by reflection makes use of impulsive ultrasound energy. The basic transducer, also called
probe, which transmits and receives the ultrasonic impulses is made up of a piezoelectric disk
(which is a ceramic crystal, usually lead zirconate
titanate) that after the application of an electrical
current, vibrates and transmits these vibrations
into the object in contact with it. The ultrasound
frequency depends on the thickness of the crystal.
The piezoelectric effect is symmetrical,so that the
same crystal can be used as a receiver to produce
small electrical signals when struck by an ultrasound wave.
Propagation in Tissue
Elastic waves at ultrasonic frequency are generated by a perturbation which causes the particles of
a given medium to vibrate. The vibration of the
particles of the medium is a basic characteristic of
the propagation of elastic waves. It is therefore
impossible for such waves to advance in a vacuum. Different modes of propagation are possible,
and in diagnostic applications, longitudinal waves
are used. The term means that the motion of the
particles in the medium is parallel to the direction
of wave propagation. The molecules move back
and forth around their intermediate position pro-
ducing bands of compression and rarefaction so
that the energy is transmitted through the medi-
4 Benign Anorectal Diseases
Fig. I.1. Elastic waves are generated by a
perturbation which causes the particles
of a medium to vibrate. The vibrations of
the particles are in the direction of propagation of the wave
um as a perturbation without transfer of matter
(Fig. I.1). Each repetition of this back-and-forth
motion is called a cycle. The length of the wave (l)
is the distance between two bands of compression
or rarefaction. The velocity at which the energy is
transmitted through the medium,which coincides
with the velocity of propagation v,depends on the
strength of the elastic forces between particles
(which relates to the elasticity of the tissue) and to
the masses of the particles (which determines
density of the medium). These two factors determine the acoustic impedance of the tissue. When
the particles are heavy,a given ultrasound energy
is transmitted with small movements of the particles; when they are light, larger excursions are
involved. The velocity of propagation can be
roughly considered constant in the frequency
interval used in diagnostic applications. The
wavelength l and the frequency f are linked to the
velocity of propagation v by the equation: v=f ¥l.
As a sound beam passes through the body, the
beam is attenuated or reduced in intensity by a
combination of absorption, reflection, refraction,
and diffusion. The intensity at each point of a
wave is defined as the energy flow per unit of time
through the unit area perpendicular to the direc-
tion of propagation at the point considered. The
amplitude of the ultrasound beam is expressed in
decibels (dB). For average soft tissues, the loss
amounts to approximately 1 dB per centimeter tissue depth for each megahertz. The acoustic
absorption is mainly due to the transformation of
the ultrasonic energy into thermal energy. Three
factors determine the amount of absorption: (1)
the frequency of the sound; (2) the viscosity of the
conducting medium, mainly linked to the protein
content; and (3) the relaxation time of the medi-
um. The relaxation time is the time it takes for a
molecule to return to its original position after it
has been displaced.Absorption is very low in fluid
media, intermediate in soft tissue, and very high
in bone and gas at the frequencies used in diagnostics (Table I.1).
Ultrasound energy is also lost to the receiving
transducer if it is reflected or refracted away from
the returning line of sight or if the beam diverges.
When an ultrasonic wave propagating in an
acoustically uniform medium reaches an interface
with a medium of differing characteristic
mechanical impedance (Table I.2), reflection and
refraction of the wave occurs. Image formation
depends entirely on the returning echoes. The
amount of reflection depends on the difference in
the acoustic impedance of the two surfaces and on
the angle of incidence of the beam. Acoustic
impedance is the product of the density and
velocity of sound in the conducting medium.
Within soft tissues, only a few percent is reflected
at each interface, but almost total reflection
occurs at tissue/gas interfaces. For incidence of a
wave over a theoretically plane surface, the reflec-
Table I.1. Absorption coefficients for various materials
Material Absorption coefficient (dB/cm)
Water 0.002
Blood 0.2
Fat 0.6
Skeletal muscle 1-5
Bone 10
Air 35
–2.5
Section I • Fundamental Principles of Ultrasound Imaging 5
Table I.2. Resonance coefficients for various interfaces
Resonance coefficient
Interface between water and fat 3.5%
Interface between water and bone 68%
Interface between water and air 100%
tion obeys Snell’s law for light, and waves are
reflected at an angle equal to the angle of incidence (specular reflection).When the incidence of
the ultrasound wave between two media is perpendicular to the surface (normal incidence)
(Fig. I.2a),the reflection is optimal.When the incidence is oblique, the reception of the reflected
ultrasound by the transducer depends on the
angle of incidence (Fig. I.2b). Using a rotating
endoprobe within mainly circular structures such
as sphincters, most specular reflections will be at
right angles and so maximal (Fig. I.3). Strength
and directionality are the cardinal features of
echoes from flat surfaces.Where the irregularities
in the surface are of the same order of size as the
ultrasound wavelength, a different mechanism –
known as scattering – produces echoes. Here, each
small interface is vibrated by the mechanical
shock it has received from the incident ultrasound
pulse. The vibratory energy is reradiated equally
in all directions, each discontinuity behaving as
an isolated point source of ultrasound (Fig. I.4). It
is important to note that the texture in the image
is an interference pattern and is not a one-to-one
Fig. I.3. Using a rotating endoprobe within mainly circular
structures, most specular reflections will be at right angles
and so maximal
representation of the histological reality.
Scattering within biological tissues reduces the
propagating energy so that it contributes to attenuation together with reflection and absorption.
Whatever the properties of biological tissues (the
amount of collagen fibers is the dominant element
in determining the value of characteristic
Fig. I.2. Specular reflection: normal incidence (a), oblique
incidence (b)
Fig. I.4. Diffraction develops when the interface is much
smaller than the wavelength of the incident wave that is scattered uniformly in all directions (T = transducer)
6 Benign Anorectal Diseases
Fig. I.5. Refraction of the ultrasound wave along the pathway
with oblique incidence between two media with different
propagation velocities: incident wave (1), reflected wave (2),
interface (3), normal line (4), refracted wave (5)
impedance) contribute to the formation of discontinuity of characteristic impedance and their
variations, the physics of scattering or reflection
of widespread structures is not yet possible to
establish. Fat, gas, and bone have very different
densities, but various soft tissues have very similar densities, and changes in impedance are due to
alteration in the elasticity of the tissues. When the
mechanical vibration encounters an obstacle (the
interfaces between one tissue and another, discontinuity in the biological tissue, cavities full of
fluid, air bubbles, or foreign bodies) as the wave
front advances,part of the energy is reflected and
the rest continues or is refracted, with an angle of
refraction different from the angle of incidence
(Fig. I.5).
The echoes from deep structures are much
weaker than those from closer structures due to
greater signal attenuation. Accurate adjustment of
amplification is important in order to enable adequate screen display. This is achieved by applying
progressively increasing amplification (gain) to
later echoes in proportion to their depth using a
time-varying amplifier that is triggered when
each ultrasound pulse is sent.This is the time gain
compensation (TGC), an important user control
that must be set to equalize the image brightness
for superficial and deep structures (Fig. I.6).
Adjustments influence both axial and lateral resolution (Fig. I.7).Axial resolution is the capacity to
resolve two-point reflectors in the direction of the
axis of the ultrasound beam. Lateral resolution
signifies the capacity for resolving two-point
Fig. I.6. Time gain compensation
reflectors at an equal distance from the transducer but situated in two different directions from it.
As the gain increases, the rendering of details in
the images deteriorates, and different images are
obtained for the same objects, at the same distance, with the same transducer and hence with
the same potential lateral resolution (Fig. I.8).
Section I • Fundamental Principles of Ultrasound Imaging 7
Fig. I.7. Influence of gain adjustment of
echographic equipment on the resolution
obtained in mode B display. As the gain
increases (right-hand figure) the rendering of details in the images deteriorates
Scanning Methods
The same transducer used to emit the ultrasonic
impulse responds to mechanical vibrations by
generating a corresponding electrical signal. In
the conventional pulse-echo ultrasound process,
signals are recorded at a depth calculated from the
time delay between transmission and receipt of
the echoes using the value of the speed and sound
in tissue to convert from time to depth. The signal
is transmitted to a series of electronic circuits and
frequently presented as a luminous signal on the
screen of an oscilloscope (Fig. I.9). By making a
correlation between the luminous point on the
screen and the distance traveled by the ultrasonic
waves advancing within the tissues, an image is
formed of the organization of the layers encountered by the ultrasound beam in the direction in
which the transducer is pointing. The images used
in clinical echography may appear as images of
the amplitude of the echo signals in relation to the
a b
Fig. I.8. The uniform time gain compensation makes the image in b brighter
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