الفهرس 
BASICS OF ULTRASOUND
Limitations of Ultrasound ImagingOnly 14 pages are availabe for public view
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Abstract
Ultrasound is a valuable tool for imaging critical soft
tissue structures relevant to the sympathetic chain; guiding
needle advancement, and confirming the spread of injectate in
the proper fascial plane, without exposing healthcare providers
and patients to the risks of radiation.
There are only a few reports and observational studies
that have demonstrated the advantages of ultrasound-guided
stellate ganglion block over the traditional fluoroscopy-guided
technique. However, despite a lack of scientific evidence in the
past, pain practitioners followed a common-sense and soundjudgment
approach when they transitioned from the blind
approach to the now-routine fluoroscopic-guided approach for
performing stellate ganglion block (SGB). And with the
introduction of ultrasound guidance in pain management, many
pain practitioners are following the same path.
Ultrasound-guided stellate ganglion block, with direct
visualization of the multiple vulnerable soft tissue structures
compacted in a tight vascular space around the sympathetic
chain, appears to be safer and more effective than traditional
approaches. While future clinical studies will undoubtedly further establish ultrasound-guided SGB as the superior
approach, the concept is already very appealing today, to the
point that RCTs comparing ultrasound-guided SGB to the blind
approach, or even to the fluoroscopy guided technique, may not
be necessary in the future.
That will be useful in treatment of pain syndromes as
complex regional pain syndromes type I (reflex sympathetic
dystrophy) and type II (causalgia), hyperhidrosis, refractory
angina, phantom limb pain, herpes zoster, and pain of the head
and neck. Also, it is of value in arterial vascular insufficiency
which include Raynaud syndrome, scleroderma, obliterative
vascular diseases, vasospasm, trauma, and emboli. No benefit is
seen in patients with venous insufficiency.
Recent advances in US technology and image processing
capabilities of US machines have made it possible to image the
Thoracic Paravertebral Space(TPVS). Being able to delineate
the relevant anatomy of the TPVS before and during a TPVB in
real-time may offer several advantages. Ultrasound is
noninvasive, safe, simple to use, with no radiation, and it
appears to be a promising alternative to traditional landmarkbased
techniques for thoracic paravertebral block (TPVB).
Using US, one is able to preview the paravertebral anatomy
before block placement and determine the depth to the
transverse process and pleura. The latter defines the maximum safe depth for needle insertion and may help reduce the
incidence of pleural puncture. Ultrasound guidance during
TPVB also allows the block needle to be advanced accurately
to the TPVS and visualize the distribution of the local
anesthetic during the injection in real-time. This may translate
into improved technical outcomes, higher success rates, and
reduced needle-related complications. It is also an excellent
teaching tool for demonstrating the anatomy of the TPVS and
has the potential to improve the learning curve of this
technique.
Endoscopic ultrasound (EUS)-guided celiac plexus block
is a promising new method for controlling the abdominal pain
associated with chronic pancreatitis. The EUS-guided celiac
plexus block technique provided more substantial pain relief
and a greater duration of pain relief than the CT technique.
Furthermore, the EUS technique was the preferred procedure
among the majority of study subjects who had experienced both
techniques. This was attributed to a more liberal use of
conscious sedation and the lack of back pain usually associated
with the transposterior CT approach.
Indications for celiac plexus block are several. Celiac
plexus block with local anesthetic is indicated as a diagnostic
tool to determine whether flank, retroperitoneal, or upper
abdominal pain is sympathetically mediated via the celiac plexus. Daily celiac plexus blocks with local anesthetic are also
useful in the palliation of pain secondary to acute pancreatitis.
Celiac plexus block is also used successfully to palliate the
acute pain of arterial embolization of the liver for cancer
therapy and to reduce the pain of abdominal “angina”
associated with visceral arterial insufficiency.
Neurolytic celiac plexus block used to treat pain
secondary to malignancies of the retroperitoneum and upper
abdomen. It is also useful in some chronic benign abdominal
pain syndromes.
Ultrasound can be successively used to locate
thesacrococcygeal joint and facilitate the performance of
ganglion impar block. However, ultrasound does not replace
fluoroscopy, because lateral fluoroscopy is still required to
establish safe depth, and monitor the spread of the injectate.
Ganglion impar block can be useful in the evaluation and
management of sympathetically mediated pain of the perineum,
rectum, and genitalia. Visceral pain or sympathetically
maintained pain in the perineal area associated with the
malignancies of the pelvis may be effectively treated with
neurolysis of the ganglion impar.