Introduction : pain is a stressor that can threaten homeostasis (a steady physiological state). The adaptive response to such a stress involves physiological changes that, in the initial stages, are useful and are also potentially life- saving(Bultaci, 2007 ). Unrelieved postoperative pain may result in clinical and psychological changes that increase morbidity, mortality, costs as well as decrease quality of life and potentially increase the incidence of chronic pain. Negative clinical outcomes resulting from ineffective postoperative pain management include deep vein thrombosis and pulmonary embolism, coronary ischemia and myocardial infarction, pneumonia, poor wound healing, insomnia and demoralization. Associated with these complications are economic and humanistic implications such as extended lengths of stay, readmissions, and patient dissatisfaction with medical care. A recent study suggests that pain in ambulatory surgical patients is still undermanaged and the incidence 1
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Introduction :
pain is a stressor that can threaten homeostasis (a steady
physiological state). The adaptive response to such a stress involves
physiological changes that, in the initial stages, are useful and are also
potentially life-saving(Bultaci, 2007 ).
Unrelieved postoperative pain may result in clinical and psychological
changes that increase morbidity, mortality, costs as well as decrease
quality of life and potentially increase the incidence of chronic pain.
Negative clinical outcomes resulting from ineffective postoperative pain
management include deep vein thrombosis and pulmonary embolism,
coronary ischemia and myocardial infarction, pneumonia, poor wound
healing, insomnia and demoralization. Associated with these
complications are economic and humanistic implications such as
extended lengths of stay, readmissions, and patient dissatisfaction with
medical care. A recent study suggests that pain in ambulatory surgical
patients is still undermanaged and the incidence of moderate to severe
pain remains high (Apfel AL et al., 2003).
We all know that treatment of pain by getting rid of its causes is the
best way, but it is not always possible and especially it does not always
work fast enough. Half of the patients in US consultation rooms come for
the treatment of pain, and no part of pharmacology is better researched
than pain treatment (Barden et al, 2004).
Regional anesthesia and analgesia can be used to significantly
reduce postoperative pain scores and spare the use of systemic opioids.
Regional anesthesia can be performed at the neuraxis (epidural) or the
nerve root (paravertebral). Local anesthetic deposition at these sites will
1
selectively block nerve conduction and result in different analgesic and
side effect profiles . (Linda Le-Wendling, et al., 2015).
The paravertebral block is a selective block of the nerve roots at the
chosen levels. The resultant anesthesia or analgesia is conceptually
similar to a "unilateral" epidural anesthesia. Higher or lower levels can be
chosen to accomplish a band-like segmental blockade at the desired
levels. However, the paravertebral block does not result in
Operationally a VAS is usually a horizontal line, 100 mm in length,
anchored by word descriptors at each end, as illustrated in Fig. 1. The
21
patient marks on the line the point that they feel represents their
perception of their current state. The VAS score is determined by
measuring in millimetres from the left hand end of the line to the point
that the patient marks. There are many other ways in which VAS have
been presented, including vertical lines and lines with extra descriptors.
(Niven & Dowens 2000).
Assessment of acute pain during movement (dynamic pain):
Assessment of the intensity of acute pain at rest after surgery is
important for making the patient comfortable in bed. However, adequate
relief of dynamic pain during mobilization, deep breathing, and coughing
is more important for reducing risks of cardiopulmonary and
thromboembolic complications after surgery. Immobilization is also a
known risk factor for chronic hyperalgesic pain after surgery, becoming a
significant health problem in about 1%, a bothersome but not negligible
problem in another 10%. Effective relief of dynamic pain facilitates
mobilization and therefore may improve long-term outcome after surgery.
(Jarzyna et al., 2011).
Management of acute postoperative pain:
Opioid Monotherapy:
Opioids have been used as analgesics for more than 2,000 years and
continue to be a key element in moderate to severe acute postoperative
pain management. However, opioid-only treatment plans can result in
intolerable and dangerous adverse effects, including constipation, nausea
and vomiting, excessive sedation, and respiratory depression. Concerns
are also being raised about a possible link between opioid-only treatment
plans and a paradoxic clinical situation in which increasing doses of
22
opioid result in increasing sensitivity to pain, a condition referred to as
opioid-induced hyperalgesia ( Pasero, 2011).
Adverse effects associated with opioids commonly occur and can
prevent patients from experiencing satisfactory analgesia. In a systematic
review analyzing opioid-induced adverse effects among postoperative
patients in 45 randomized-controlled studies, 31% of patients experienced
an adverse gastrointestinal (GI) event (ileus, nausea, vomiting,
constipation), 30.3% of patients reported an adverse central nervous
system (CNS) event (somnolence, sedation), 18.3% of patients reported
pruritus, 17.5% of patients experienced urinary retention, and 2.8% of
patients had respiratory depression (Wheeler et al., 2002).
Non-steroidal anti-inflammatory drugs (NSAIDs):
NSAIDs are considered to be appropriate for mild to some moderate-
intensity acute pain and as adjuncts to opioids for the relief of more severe
acute pain. They do not produce respiratory depression or impair GI
motility so are considered an important component with acetaminophen in
a multimodal treatment plan for acute pain. (Pasero et al., 2011).
The analgesia and anti-inflammatory effects induced by NSAIDs
are the result of cyclo-oxygenase 2 (COX-2) inhibition, while the adverse
effects of NSAIDs are generally the result of COX-1 inhibition. For
example, an adverse effect of COX-1 inhibition is reduced platelet
aggregation. The most common adverse effect of NSAIDs is gastric
complications, and patients with a history of peptic ulcer disease are
among the highest risk for this adverse effect. NSAIDs can also induce
acute renal failure, particularly in patients with acute or chronic volume
depletion, cardiac failure, liver cirrhosis, ascites, diabetes, or preexisting
hypertension. (Pasero et al., 2011)
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Acetaminophen:
Because of its efficacy, safety, lack of clinically significant drug
interactions, and lack of the adverse effects associated with other
analgesics, IV acetaminophen is an attractive component of a multimodal
analgesic treatment plan. (Groudine et al., 2011)
Acetaminophen is not associated with the increased incidence of
nausea, vomiting, and respiratory depression that can occur with opioids,
or the platelet dysfunction, gastritis, and renal toxicity that are sometimes
associated with NSAIDs. (Silvanto et al., 2007)
Gabapentin and pregabalin:
Gabapentin first marketed in the nineties for its antiepileptic properties,
is known to be effective in treating chronic neuropathic pain, complex
regional pain syndromes, and restless legs syndrome. Gabapentin is
believed to act on a specific receptors, which are over expressed in the
dorsal horn of the spinal cord and in spinal ganglia in cases of
neurological injury. The advantages of gabapentin are that it does not
interact with haemostasis and does not induce respiratory depression.
Further, its anxiolytic properties can be useful preoperatively.
Recommended dosages are (300 to 3200 mg/day) in 2-3 doses.
Bioavailability of gabapentin is 36% to 60% and decreases with the
ingested dose because of good absorption at the small intestine level.
Gabapentin is not metabolized and is eliminated in the urine; therefore,
dosages should be modified in renal failure. Side effects are rare and
usually mild: dizziness,vertigo, headaches, nausea, vomiting, and
ataxia(Fassoulaki et al.,2006)
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Regional Anesthesia and local anesthetics:
Regional anesthesia is used to desensitize a specific part of the body
to a painful stimulus. It is classified into six sites of placement of local
anesthetic: topical or surface anesthesia, local infiltration, peripheral nerve
block, intravenous regional anesthesia, epidural anesthesia, and spinal
(subarachnoid) anesthesia. (Stoelting et al., 2006).
Regional anesthesia techniques may include, but are not limited to,
spinal, epidural, peripheral nerve blocks, upper and lower extremity
blocks, airway blocks, and transversus abdominis plane (TAP) blocks.
Regional anesthesia techniques may be used alone, or in combination with
other anesthetic techniques, to provide anesthesia and analgesia for a
variety of surgical and obstetrical procedures as well as for chronic pain
management. Using regional anesthesia in combination with other
anesthetic techniques can minimize side effects of an individual anesthetic
technique, maximize benefits, and offer the patient options in the selection
of anesthesia and analgesia. (Olson et al., 2010)
Multimodal Pain Management
To address the under-treatment of postoperative pain and the
limitations of opioid monotherapy, a strategy known as multimodal pain
management was introduced in the early 1990s . This approach
simultaneously administers two or more analgesic agents with different
mechanisms of action. Combination therapy using drugs with distinct
mechanisms of action may add analgesia or have a synergistic effect and
allow for better analgesia with the use of lower doses of a given
medication than if the drug was used alone (Pasero, 2011). For example,
postoperative multimodal analgesia may consist of the use of opioid and
non-opioid pharmacologic agents, as well as regional anesthesia and
25
continuous peripheral nerve block. The multimodal approach has been
used by many professional organizations, including the American Society
of Anesthesiologists (ASA) and the American Pain Society (APS)
(Jarzyna et al., 2011).
Ultrasound guidance has greatly influenced the practice of regional
anaesthesia in the last 15 years. Between 1884, the year when Carl Koller
performed the first regional block for eye surgery in Vienna, and the late
1970s, the main developments were in new local anaesthetic drugs and
the introduction of mainly anatomical methods for nerve identification.
Unfortunately, anatomy is not exactly predictable and the natural
variability of human anatomy led to poor success rates for many
peripheral nerve blocks. (Kapral et al., 1994)
Current ultrasound equipment allows much easier identification of very
small neural structures than it was possible with machines introduced
only a few years ago. In addition, adjacent anatomical structures can be
identified. (Duggan et al., 2009)
Without any doubt, direct visualization of neural and adjacent
anatomical structures is the main advantage of the use of ultrasound for
regional block techniques. An important objective for ultrasound is
visualization of the spread of local anaesthetic during injection.
Confirmation of the correct disposition of local anaesthetic avoids any
maldistribution , such as epineural, perineural or intravascular injection.
In addition, an ability to perform blocks with small volume of local
26
anaesthetic is mainly based on an ability to observe the spread of the local
anaesthetic directly (Latzke et al., 2010).
Basic of ultrasound physics:-
Ultrasound is a form of mechanical sound energy that travels through a
conducting medium (e.g., body tissue) as a longitudinal wave producing
alternating compression (high pressure) and rarefaction (low pressure).
Sound propagation can be represented in a sinusoidal waveform with a
characteristic pressure (P),wavelength (λ), frequency (f), time (T) and
velocity (speed (c) + direction) (Figure-1). (Edler and Lindstrom, 2004)
)Figure -1 :(ultrasound waves, High-frequency probes produce shorter wavelength waves, and low-frequency probes produce longer wavelength waves(Edler and
Lindstrom, 2004)
Tissue appearance under ultrasound:
*Hyperechoic areas :- have a great amount of energy from returning
echoes and are seen as white.
*Hypoechoic areas: - have less energy from returning echoes and are
seen as gray.
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*Anechoic areas without returning echoes are seen as black.
Ultrasound waves and tissue interaction:
The speed of ultrasound waves through biological tissue is based on
the density of tissues, and not the frequency of the ultrasound waves.
The greater the tissue density, the faster the ultrasound waves will
travel. The image processor in the ultrasound machine assumes that the
ultrasound waves are travelling through soft tissue at a velocity of
1,540 m/sec. Three things can happen to ultrasound waves as they
travel through tissue reflection, attenuation, and refraction. (Weyman,
1994)
1-Reflection:
The generation of ultrasound images is dependent on the energy of
the echoes that return to the probe. The amount of reflection of
ultrasound waves is dependent on the difference in acoustic impedance
at the interface between different tissues. Acoustic impedance is the
resistance of a material to the passage of ultrasound waves. (Figure -2).
The greater the difference in acoustic impedance at tissue interfaces,
the greater the percentage of ultrasound waves that is reflected back to
the probe to be processed into an image.(Middleton et al., 2004)
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(Figure -2): Specular reflection vs. scattering reflection.(Middleton et al.,
2004)
2-Attenuation:
Attenuation of ultrasound waves is dependent on three factors:
Attenuation coefficient of the tissue.
Distance travelled.
Frequency of the ultrasound waves.
Attenuation is inversely related to frequency; the higher the frequency
of the ultrasound wave, the greater the attenuation. Therefore, high
frequency probes have less tissue penetration due to greater
attenuation, which makes imaging of deeper structures difficult with
high-frequency probes.(Jespersen,1998)
3-Refraction:
When the acoustic impedance between tissue inter faces is small,
the ultrasound wave’s direction is changed slightly at the tissue
interface, rather than being reflected directly back to the probe at the
inter face this is analogous to the bent appearance of a fork in water,
which is caused by refraction of light waves at the air/water inter face.
Refracted waves may not return to the probe in order to be processed
into an image. Therefore, refraction may contribute to image
degradation (Figure -3).(Otto, 2000)
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(Figure-3): Refraction vs. reflection.(Otto, 2000)
Resolution: It is the ability to distinguish two close objects as separate, is very
important in ultrasound-guided regional anaesthesia. There are two
types of resolution:
Axial resolution.
Lateral resolution.
1-Axial resolution:
Axial resolution is the ability to distinguish two objects that lie
in a plane parallel to the direction of the ultrasound beam. Axial
resolution is equal to half of the pulse length. Higher frequency probes
have shorter pulse lengths, which allows for better axial resolution.
The ultrasound probe emits ultrasound waves impulses, not
continuously. These pulses of ultrasound waves are emitted
intermittently as the probe has to wait and listen for the returning
echoes.(Chan, 2009)
2-Lateral resolution:
Lateral resolution is the ability to distinguish two objects that lie
in a plane perpendicular to the direction of the ultrasound beam.
Lateral resolution is related to the ultrasound beam width, the more
narrow (focused) the ultrasound beam width, the greater the lateral
resolution. High frequency probes have narrower beam widths, which
allows for better lateral resolution. Poor lateral resolution means that
two objects lying side by side may be seen as one object. The position
30
of the narrowest part of the beam can be adjusted by changing the focal
zone.(Chan, 2009).
Ultrasound machine controls:
1-Depth:
The depth of tissue imaged can be adjusted on the machine and
relates to the type of probe being used. Low-frequency probes will be
able to image deeper tissue depths than high-frequency probes. With a
linear array probe, as the depth is increased, the image on the screen
will appear narrower and structures will appear smaller, but the width
of the field of view is relatively constant. Notice that the field of view
is constant from 3 cm to 6 cm but at 2 cm it has decreased. (Kossoff,
2000)
(Figure -4) :-General Electric (GE) ultrasound portable device control pannel
2-Frequency:
Variable-frequency probes allow changes in frequency within a
narrow range. An 8 to 13 MHz probe allows selection of frequency
between 8 and 13 MHz. The lower frequencies are used for deeper
31
structures and the higher frequencies are used for more superficial
structures. Select a frequency that balances penetration and resolution.
(Lawrence, 2007)
3-Gain:
Ultrasound probes transmit ultrasound waves 1% of the time and
spend the remaining 99% of the time listening for the returning echoes.
Increasing the gain increases signal amplification of the returning
ultrasound waves, in this way the gain function can be used to
compensate for loss of energy due to tissue attenuation. Returning
ultrasound waves are referred to as “signal” while background artifact
is referred to as “noise”. Increasing the gain increases the signal-to-
noise ratio. However, if the gain is increased too much, the screen will
have a “whiteout” appearance and all useful information is lost.
(Lawrence, 2007).
4-Color-flow Doppler:
Color-flow Doppler allows for detection of flow within vascular
structures. Moving objects, such as red blood cells (RBCs), affect
returning ultrasound waves differently than stationary objects. Color-
flow Doppler can differentiate between RBCs moving away from the
probe and RBCs moving towards the probe. Red blood cells moving
towards the probe will return ultrasound waves at a higher frequency
and are displayed as red; RBCs moving away from the probe will
return ultrasound waves at a lower frequency and are displayed as blue.
(Figure-5)(Otto,2000).
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(Figure -5): Radial artery flow is seen as red when the probe is tilted towards the
direction of flow.(Otto, 2000).
5-Pulse-wave Doppler:
Pulse-wave Doppler provides flow data from a small area along
the ultrasound beam. The area to be sampled can be selected by the
operator. Once pulse-wave Doppler is selected, the image is frozen and
the operator selects the area to be sampled. The pulse-wave
information is displayed graphically at the bottom of the screen as well
as heard(figure -6).(Otto, 2000)
)Figure -6 :(Pulse-wave Doppler showing arterial flow in the femoral artery.(Otto, 2000)
33
Needle insertion:
1-In plane (IP)
The needle is inserted in the same plane as the ultrasound beam.
The goal is for the path of the needle to be entirely within the beam of
the ultrasound. The more parallel the needle is to the probe (shallower
angle of insertion) the easier the needle will be to visualize. When
inserting the needle, the goal is to be as close to parallel to the probe as
possible. Since with many blocks it will be impossible for the needle to
be parallel to the probe, the goal should be to have as shallow an angle
of insertion as possible. In order to achieve a shallow angle between
the needle and the probe, some blocks will require that the needle be
inserted a greater distance from the probe as opposed to right next to
the probe.(Chan, 2009)
2-Out of plane (OOP):
The needle is perpendicular to the beam of the ultrasound. The
needle is seen as a small hyperechoic dot on the screen. In an OOP
approach, the needle needs to travel a shorter distance to the target than
in-plane approach. For those making the transition from nerve
stimulation to ultrasound, the location of needle insertion in the OOP
approach is similar to the traditional nerve stimulator insertion points.
Finding the needle tip in an OOP approach can be challenging for the
beginner. The steeper the angle of insertion, the easier to see the needle
in an OOP approach.(Chan, 2009).
Advantages of ultrasound guided nerve block
Ultrasound guidance offers several potential advantages:
34
1- Direct visualization of nerves: This may replace other methods of
nerve localization, such as electrical stimulation or paraesthesia.
2- Direct visualization of anatomical structures: vessels, muscles,
bones, fascia tendons: This may help assess individual variations in
anatomy and facilitate identification of nerves.
3- Real-time control of needle advancement: This may reduce the
number of needle passes, shorten the block performance time and
lower the risk of complications caused by a needle e.g., vascular
puncture, neuropraxia or pneumothorax.
4- Assessment of LA spread around the nerves and immediate
supplementary injections in case of insufficient spread: This may
hypovolemia and low fixed cardiac output e.g. sever aortic stenosis(Silva
and Halpern, 2010).
Complications:
Complications of central neuraxial blockade, much depending on the
experience in patient management, as well as materials, equipment, and the
presence of risk factors, have been reported to occur at various frequencies
(Moen et al, 2004).
Neurological complications resulting from accidental penetration of the
dura are similar to those that occur with spinal anesthesia. Inadvertent dural
puncture and postdural puncture headache, direct neural injury, total spinal
anesthesia, and subdural block have been commonly reported.
1) Inadvertent dural puncture and postdural puncture
headache:
The incidence of inadvertent dural puncture ranges between 0.19–0.5%
of epidural catheter placements. Postdural puncture headache (PDPH),
described as a positional, bilateral frontal-occipital, nonthrobbing pain, may
develop in as much as 75% of patients (Van de Velde et al, 2008).
2) Direct neural injury:
Direct neural injury has a reported incidence of 0.006%, and has been
associated with paresthesias during needle placement and pain on injection
(Ruppen et al, 2006).
40
3) Total spinal anesthesia:
Total spinal anesthesia may occur if the solution used for epidural
anesthesia is inadvertently administered into the intrathecal space in large
volumes. Symptoms are of a rapidly arising subarachnoid block, potentially
resulting in cardiovascular collapse and apnea requiring prompt
resuscitation. Provided that immediate, skilled resuscitative efforts are made,
complete recovery should be expected (Hara and Sata, 2006).
4) Epidural Hematoma:
Hemorrhagic complications are serious adverse outcomes that may
arise from neuraxial anesthesia. Epidural hematoma is a rare, but potentially
devastating, complication that requires emergency decompression in case of
clinical deterioration. It is rarely attributed to an arterial source, and can
develop spontaneously (Horlocker, 2004).The risk is reported to increase
15-fold when there is a concomitant use of anticoagulants, and appropriate
precautions are not taken. Appropriate timing of anticoagulant
administration is important in decreasing the risk of bleeding (Horlocker et
al, 2010).
5) Epidural catheter related infections:
Epidural abscess and meningitis has been reported to occur in 1: 1000
and 1: 50,000 catheter placements, respectively.The classic presentation
signs and symptoms are severe midline back pain, fever, and leukocytosis,
with or without neurological symptoms (worsening lower limb weakness and
paraplegia, incontinence, irradiating pain, nuchal rigidity, and headache).
Symptoms commonly appear after removal of the epidural catheter (Christie
and McCabe, 2007).
6) Pruritis:
41
Pruritis is the most common side effect of neuraxial analgesia. The
incidence and severity is dependent on the opioid dose, and is more frequent
with intrathecal opioids than with epidural opioids (58% versus 30%). The
cause of pruritus is not well understood, but it is unlikely to be related to
histamine release. Antihistamines, often prescribed to treat pruritus after
neuraxial opioids, are usually ineffective. There is increasing evidence that
neuraxial opioid-induced pruritus is mediated through central μ-opioid
receptors. Opioid antagonists (e.g. naloxone) or partial agonist-antagonists
(e.g. nalbuphine) are effective in relieving pruritus (Herman et al, 1999).
7) Nausea and Vomiting:
With an estimated incidence of 17% to 35%, nausea and vomiting may
occur as the opioid diffuses from the site of the epidural injection to the
chemoreceptor trigger zone for vomiting located in the 4th ventricle (Bragg,
1998). This side effect usually occurs 4 to 6 hours after administration and
may be associated with activity, such as turning and coughing (Naber et al,
2009).
8) Urinary Retention:
It usually occur in the first 24 to 48 hours and then resolves
spontaneously. Signs and symptoms include a lack of urge to void and
bladder distention. The underlying mechanism may be the action of the
narcotic on the spinal nerves innervating the detrusor muscle, thereby
altering bladder tone (atonia) and predisposing to bladder over distension
and increased residual volumes. For unknown reasons, urinary retention
occurs more often in elderly men, patients with pre-existing bladder
disorders, and during pregnancy and the postoperative period.Many centers
insert an indwelling Foley catheter for the duration that the epidural catheter
remains in place. If a Foley catheter is not used, intermittent catheterization
42
may be necessary. However, catheterization in some populations may in fact
further increase the risk of infection (Lingaraj et al, 2007).
9)Hypotension:
Hypotension is a second potential narcotic-related side effect of
epidural analgesia. However, as epidural narcotics have a localized action
and do not produce sympathetic nervous system blockade, they generally
have little effect on blood pressure. The hypotensive state may be a result of
fluid volume changes or immobility postoperatively, in which case IV fluids
are indicated.Local anesthetics are not specific to sensory afferent fibers, and
they do block autonomic and motor efferent fibers. This sympathetic
blockade can lead to hypotension and exacerbate or intensify postural
hypotension due to hypovolemia. As a result, postural hypotension may
restrict early ambulation and potentially increase morbidity. Therefore,
assessment of the patient's motor strength prior to ambulation is
critical (Roffey et al, 2001).
10) Respiratory Depression:
The most serious narcotic-related side effect associated with epidural
analgesia is respiratory depression. It is manifested by a decrease in the
depth of respirations or tidal volume, followed later by a decrease in
respiratory rate. Initially, the patient may be able to maintain an adequate
respiratory rate but the hyperventilation that occurs does not allow adequate
oxygen CO2 exchange. This impaired gas exchange leads to mental status
43
changes indicative of increasing CO2 levels. Therefore, a decrease in the
patient's level of consciousness or arousability is considered the first and the
best indicator of respiratory depression (Wild, 1990).
Technique of paravertebral block:
Manoj K. Karmakar, MD; Anthony M-H. Ho, MD lumbar
paravertebral block (lPVB) is the technique of injecting local anesthetic
alongside the lumbar vertebra close to where the spinal nerves emerge
from the intervertebral foramen. This produces unilateral, segmental,
somatic, and sympathetic nerve blockade, which is effective for
anesthesia and in treating acute and chronic pain of unilateral origin from
the abdomen. Hugo Sellheim of Leipzig (1871–1936) is believed to
have pioneered lPVB in 1905. Kappis, in 1919, developed the technique
of paravertebral injection, which is comparable to the one in present-day
use. Although paravertebral block was fairly popular in the early 1900s, it
seemed to have fallen into disfavor during the mid and later part of the
century, the reason for which is not known. In 1979 Eason and Wyatt
rekindled interest by describing a technique of paravertebral catheter
placement. Our understanding of the safety and efficacy of lPVB has
improved significantly in the last 25 years, and there has been a gradual
renewal of interest in this technique. Currently it is used not only for
analgesia but also for surgical anesthesia, and its application has been
extended to children(Kirchmair et al., 2001)
Classic method:
44
The classic insertion technique for PVB is percutaneous and has been
described by Eason and Wyatt. Similar to epidural insertion, loss of
resistance is felt immediately after puncturing the superior
costotransverse ligament, which represents the posterior border to the
paravertebral space. Approximately 2.5 cm lateral to the midline of the
spine, the transverse process is touched and a needle is directed over
(commonly) or under the boney landmark no more than 1 cm and local
anesthetic with or without a catheter is inserted. The skin to paravertebral
distance is, on average, 5.5 cm. The technique is also perfectly described
by Hounsell. Percutaneous insertion has a failure rate of 10%.
Ultrasound guided technique:a)Transverse scan :
With this scanning technique,the transducer is positioned 4 to 5 cm
lateral to lumbar spinous processes at the L3-L4 level and directed
slightly medially to assume a transverse oblique orientation.This
approach allows imaging of lumbar paravertbral region with the erector
spinae muscle, psoas major muscle, quadratous lumborum muscle,
transverse process and the anterolateral surface of vertebral body.In the
transverse oblique view,the inferior vena cava(IVC) On right sided scan,
or the aorta, on the left-sided scan, also can be seen and provide
additional information on the location of the psoas muscle, which is
positioned superficial to these vessels. In this view, the psoas muscle
appears slightly hypoechoic with multiple hyperechogenic striations
within. The lower pole of the kidney can often be seen, when scanning at
the L2-L4 level, as an oval structure that ascends and descends with
respirations(Gadsden JC et al., 2008). The key to obtaining adequate
images of the psoas muscle and lumbar paravertebral space with the
45
transverse oblique scan is to insonate between two adjacent transverse
processes. This scanning method avoids acoustic shadow of the
transverse processes, which obscures the underlying psoas muscle and the
intervertebral foramen (angle between the transverse process and
vertebral body) and allows visualization of the articular process of the
facet joint (APFJ) as well. Because the intervertebral foramen is located
at the angle between the APFJ and vertebral body, lumbar nerve roots
often can be depicted.(Farny j et al., 1994)
A
B C
Figure 2: (A) Ultrasound anatomy of the lumbar paravertebral space using transverse oblique view. SP, spinal process; ESM, erectors spinae muscle; QLM,
46
quadratus lumborum muscle; PsMM, psoas major muscle; VB, vertebral body. The lumbar plexus root is seen just below the lamina as it exits the interlaminar space and enters into the posterior medial aspect of the PsMM. (B) Needle path in ultrasound-guided lumbar paravertebral block using transverse oblique view. LP, lumbar plexus; PsMM, psoas major muscle; VB, vertebral body. (C) Spread of the local anesthetic solution . Due to the deep location of the space, spread of the local anesthetic may not always be well seen. Color Doppler imaging can be used to help determine the location of the injectate.(Cowie B et al., 2010)
b)Paramedial sagittal scan:
Kirchmair and colleagues suggested a paramedial sagittal scan
technique with transverse scan to delineate the psoas major muscle at the
L3-L5 level with the patient in the lateral position. Once a satisfactory
image is obtained, the needle is inserted in-plane medial to the transducer
approximately 4 cm lateral to the midline. Then the needle is advanced
until the correct position is confirmed by obtaining a quadriceps motor
response to nerve stimulation (1.5-2.0 mA). Needle-nerve contact and
distribution of the local anesthetic is not always well seen, although nerve
roots may be better visualized after the injection. Injection, dosing, and
monitoring principles are the same as with the nerve stimulator-guided
technique(Doi et al., 2010).
47
Figure 3: Ultrasound image of the lumbar
paravertebral space demonstrating the
complex anatomy of the region. LP,
lumbar plexus; VB, vertebral body. Power
Doppler ultrasound is capturing the flow
in the inferior vena cava (IVC). The right
kidney is also visualized.
Figure 4: Transverse image of lumbar
paravertebral space demonstrating
sacrum and transverse process (TP) of L5.
Starting the scanning process from the
sacral area and progressing cephalad
allows the identity of the individual
transverse processes (levels). As the
transducer is moved cephalad and the
surface of the sacrum disappears, the next
osseous structure that appears is the
transverse process (TP) of L5.
48
Figure 5: Transducer position (curved,
phased array) and the needle insertion
plane to accomplish ultrasound- guided
lumbar paravertebral block in the
longitudinal view and an out-of-plane
needle insertion.
Figure 6: Simulated needle insertion
paths (1,2) to inject local anesthetics at
two different levels to accomplish a
lumbar paravertebral (LP) block. Needles
(1 and 2) are seen lodged about 2 cm
deeper and between the transverse
processes (TPs) using an out-of-plane
technique.
More recently, Karmakar and colleagues described the "trident sign
technique," which uses an easily recognizable ultrasonographic landmark,
transverse processes, and an out-of-plane needle insertion. The trident
sign technique derives its name from the characteristic ultrasonographic
appearance of the transverse processes (trident) to estimate the depth and
location of lumbar paravertebral space . After application of ultrasound
gel to the skin over the lumbar paravertebral region, the ultrasound
transducer is positioned approximately 3 to 4 cm lateral and parallel to
the lumbar spine to produce a longitudinal scan of the lumbar
49
paravertebral region (Figure 7). Then the transducer is moved caudally,
while still maintaining the same orientation, until the sacrum and the L5
transverse process become visible (Figure 8). The lumbar transverse
processes are identified by their hyperechoic reflections and acoustic
shadowing beneath which is typical of bone. Once the L5 transverse
process is visible, the transducer is moved cephalad gradually, to identify
the L3-L4 level. The goal of the technique is to guide the needle through
the acoustic window between the transverse processes (between the "teeth
of the trident") of L3-L4 or L2-L3 into the posterior part of the psoas
major muscle (Figure 2B). After obtaining ipsilateral quadriceps muscle
contractions, the block is carried out using the previously described
injection and pharmacology considerations (Figures 6 and 7).
Figure 7: Local anesthetic (LA) disposition during injection of local anesthetic into
the psoas muscle and the L2-L3 level. The spread of LA is often not well seen using
coagulation profile (bleeding time, prothrombine time, international
normalized ratio and partial thromboplastine time), liver functions, and
kidney functions were fulfilled.
)Figure 1:(Visual analogue scale (VAS)Verbal rating scale (VRS) and Numerical
rating scale (NRS)
General anaesthesia:-
Before the induction of general anaesthesia:
Intravenous access was established and IV fluids started, Monitoring of
the patients in the form of5-Lead ECG, Arterial Blood Pressure (Non
Invasive Blood pressure monitoring) and Pulse oximeter were conducted.
Prior to the regional block, IV access and arterial cannulation with local
anesthetic infiltration will be established and patients will be monitored
with electrocardiography, blood pressure monitoring (noninvasive), pulse
oximetry and capnogram.
53
Insertion of lumbar paravertebral catheter / lumbar epidural catheter
was done before induction of general anesthesia.
Induction of general anaesthesia:
After insertion of epidural/paravertebral catheters patients will be
turned supine. General anesthesia will be induced with IV fentanyl 1–2
mcg/kg, propofol 2–3 mg/kg followed by rocuronium 0.5–0.8 mg/kg to
facilitate endotracheal intubation.
Maintainance of general anaesthesia:
Anesthesia was maintained with Isoflurane 1.5% and rocuronium
0.15mg/kg as a maintainance dose every 30 minutes till the end of the
procedure. Ventilation parameters was adjusted as follows: TV = 7
ml/kg, respiratory rate = 12/min. and peak inspiratory pressure 30- 35 cm
H2O. End tidal CO2 was maintained between 35-40 mmHg.
Heart rate and mean arterial blood pressure (MAP) were monitored
throughout the operation and maintained within ± 20% of the
preoperative baseline by giving IV bolus doses of fentanyl approximately
1 mcg/kg if the MAP or heart rate increased more than 20% from the
baseline.
Recovery from general anaesthesia:
After the end of operation, reversal of neuromuscular blockade was
done by neostigmine 0.04-0.07 mg/kg and atropine 0.02 mg/kg. When
sufficient spontaneous breathing was established and the patient
responded adequately to instructions, the trachea was extubated after
gentle oropharyngeal suction. After emerging from anesthesia, the
patients was transferred to the post anesthesia care unit (PACU) for a 2
hours observation period .
54
Techniques of lumbar paravertebral block (PVB) :
A standard regional anesthesia tray was prepared with the following
equipment:
Sterile towels and 4"x4" gauze packs
20-mL syringes with local anesthetic .
Sterile gloves and marking pen.
One 1½" 25-gauge needle for skin infiltration
An 18 gauge 8 cm needle epidural set(Perifix.B.BRAUNMelsungen
AG).
Syringe pump(Fresenius Kabi) ,
GE LOGIQ P5 ultrasound machine
The lumbar paravertebral block (PVB) will be performed in the
preoperative area while the patient in the sitting position and leaning
forwards. After surgical disinfection of lumbar paravertebral areas with
protection of the ultrasound probe and cable with a sterile ultrasound
probe cover, the lumbar paravertebral space (LPVS) was identified with
ultrasound , using a5-8 MHz curved array ultrasound transducer
probe placed over a spinous process in the mid-line in a longitudinal
fashion . Once the best image of the interspace structures appeared,
Under sterile conditions,4-6 mL of local anesthetic (Lidocaine1 %) was
infiltrated subcutaneously alongside the line where the injections was
made . an 18 gauge 8 cm epidural needle(Perifix.B.BRAUNMelsungen
AG) was utilized for locating the paravertebral space
55
, The tip of the needle will be advanced under direct vision to
paravertebral space which is present at 6-8cm depth from skin surface in
lumbar region. Saline (3 mL) will then injected to:
a- demonstrate the position of injectate.
b- allow easier passage of the catheter, to a distance of 2-3 cm beyond
the needle tip.
An initial test dose of 3 mL of 2% lidocaine mixed with 1:200,000
epinephrine was injected followed by 0.5% bupivacaine(15-20ml) (0.3
mL/kg), administered over 10 minutes after recording arterial blood
pressure.
Technique of lumbar epidural block :
Epidural block will be performed in all patients in the sitting position
with binding forward and the legs are allowed to hang over the edge of
the bed with the feet supported by a stool. The shoulders are hunched
forward and the patient is encouraged to hug a pillow in towards the
abdomen to provide anterior flexion of the spine.Then anatomical land
mark will be identified by palpating the iliac crests that lie opposite the
disc between L4&L5. The skin surrounding this area will be sterilized by
povidone iodine solution and skin wheal will be infiltrated with local
anesthetic (Lidocaine 2%). using 22 gauge needle then the epidural
catheter 20 gauge will be placed at selected interspaced using midline
approach and saline loss of resistance technique through an 18-G touhy
epidural needle under complete sterile technique and directed
perpendicular to skin. Only 5 cm of the catheter will be left in the space
and the test dose (3ml Lidocaine 2%+1:200,000 adrenaline) will be
injected through the catheter to exclude subarachnoid and intravascular
56
catheter position. Epidural analgesia was done by using 0.5% bupivacaine
(5-8ml)( 0.1ml/kg) as loading dose.
In both groups continous infusion of bupivacaine 0.125% was started
at a rate of (0.1 ml/kg/hr) with fentanyl 1mcg/ml and maintained
throughout the period of the study(24 hours).
Hypotension was treated with intravenous ringer’s solution 15 ml/kg and
ephedrine 10 mg as needed to keep MAP more than 65 mm Hg.
Bradycardia ( HR < 60/ min.) was treated with atropine 0.01-0.02 mg/kg.
The following parameters were measured:
1-Demographic characteristics: Age in years, body mass index and ASA physical status.
2-Operative details: duration of surgery (time started from surgical incision till removal of surgical drapes).
3-Mean arterial blood pressure, heart rate at 0, 30 min, 1, 2, 6, 12, 24hr after the block.
4- respiratory rate and arterial oxygen saturation(Sao2) at 0,30 min, 1,2,6,12,24hr after surgery.
5-Postoperative pain level by 10-cm visual analogue scale(VAS) from 0 ( no pain) to 10 (unbearable pain) at 1, 2,6, 12, 24 hours after surgery. If VAS will be higher than 4, the infusion will be increased up to (10 ml/hr).
6- Pain rescue-analgesia consumption after 24 hours. If pain score exceed
4 despite the maximum infusion rate of bupivacaine, rescue analgesia
5mg bolus of morphine will be administered intravenous to achieve
satisfactory pain control, can be repeated every 4-6 hours.
57
Complications:
Postoperative nausea and vomiting, rescue antiemetics were offered to
any patient who complained of nausea or vomiting.
Sedation was measured by using Ramsay sedation scale (If Awake;
VAS was measured at rest and on patient's movement (knee flexion), at1,2,6,12 and 24 hours postoperative (table3)
61
Table (3):-visual analogue score (VAS) of both groups
Post-operative Group I (PVB)
Group II (EPB)
Test of significance
p-value
1hr At rest 4 ±3 3 ±1.62 t= 1.607 0.114On
movement4.37 ± 1.88 4.1 ± 1.81 t= 0.567 0.573
2hr At rest 2.73 ±1.68 2.06 ±1.20 t= 1.778 0.081On
movement3.7 ± 1.95 3 ± 1.41 t=1.593 0.117
6hr At rest 2.4 ±1.40 2 ±1.08 t= 1.201 0.235On
movement3.4 ± 1.57 3.07 ± 1.36 t=0.870 0.388
12hr At rest 2.2 ±1.21 2 ±1.17 t= 0.651 0.518On
movement2.4 ± 1.25 2.03 ± 0.99 t=1.271 0.209
24hr At rest 1.43 ±1.28 1 ±0.91 t= 1.499 0.139On
movement2.33 ± 1.18 2 ± 0.98 t=1.178 0.244
Data were presented as mean ± SD
Current study showed insignificant differences between both groups as regards VAS either at rest or on patient's movement as shown in fig.(1) and fig.(2)
At 1hr post-operative, there was insignificant difference between both groups as regards VAS both at rest(p=0.114) and on patient's movement (p=0.573).
At 2hrs post-operative, there was also insignificant difference between both groups as regards VAS both at rest (p=0.081) and on patient's movement (p=0.117).
62
At 6hrs post-operative, there was insignificant difference between PVB and EPB groups as regards VAS both at rest (P=0.235) and on patient's movement (p=0.388).
At 12hrs post-operative, there was also insignificant difference between both groups as regards VAS both at rest (p=0.518) and on patient's movement (p=0.209).
At 24hrs post-operative, there was also insignificant difference between both groups as regards VAS both at rest (p=0.139) and on patient's movement (p=0.244).
VAS R 1 VAS R 2 VAS R 6 VAS R 12 VAS R 240
0.5
1
1.5
2
2.5
3VAS at rest
PE
Fig. (1) :- VAS values at rest
63
VAS M 1 VAS M 2 VAS M 6 VAS M 12 VAS M 241
1.5
2
2.5
3
3.5VAS at movement
PE
Fig.(2):VAS values on patient's movement
Total pain rescue-analgesia consumption during 24 hours:
As regards total morphine consumption in the first post-operative 24
hours (5 mg morphine were given as bolus dose when VAS exceeds 4
despite the maximum infusion rate of bupivacaine),the current study
showed no statistically significant difference (p>0.05) between PVB and
EPB groups.
Table (4) :- Total pain rescue-analgesia consumption during 24 hours (mg/24h)
Groups Group PVB Group EPB Test of of
significance
P - value
Total-analgesia
consumption (mg morphine/24 h)
6.84 ± 2.48 6.58 ±2.91 0.30=t0.77
64
Group P Group E6
8
Fig.(3): Total analgesic consumption during 24 hours (mg morphine/24 h)
Mean arterial blood pressure (MAP) -:
As regards comparing mean arterial blood pressure (MAP) between
both groups ;Current study showed statistically highly significant change
in MAP in EPB group as compared with PVB group at1,2,6,12 and 24hr
postoperative as shown in table(5)
(Table 5):mean arterial blood pressure (MAP) of both groups in mmHg
Data were presented as mean ± SD*significant **highly significant
65
MAP at 1hr showed highly significant difference between both groups (p<0.001),Also at 2hrs, there is high significant difference in MAP between PVB and EPB groups (p<0.001),At 6hrs, there is high significant difference in MAP between both groups as p<0.001At 12hrs, MAP showed high significant difference in PVB and EPB groups (p<0.001).Also there was high significant difference in MAP at 24hrs post-operative between PVB and EPB groups.
MAP0 MAP1 MAP1 MAP2 MAP6 MAP12 MAP2460
65
70
75
80
85
MAP
Group PGroup E
Fig.(4): MAP values in all groups (mm Hg)
Heart rate (HR) -:As regards heart rate(HR) in both groups ,current study showed
insignificant decrease in heart rate in EPB group as compared with PVB
group at 1,2,6 and 12hrs post-operative.
Table (6):-Heart rate (HR) of both groups
HR (beat/min)
Group I (PVB)
Group II (EPB)
Test of significant
p- value
66
Base line 79.84±3.27 80.26±2.68 t= 0.43 0.671 hrs. 79.64±2.67 78.61±2.59 t= 1.79 0.062 hrs. 78.53 ±
2.0176.68 ± 2.21
t= 3.63 0.01*
6 hrs. 79.32 ± 2.77
77.47 ± 2.95
t= 1.98 0.05*
12 hrs. 79.32 ± 2.77
77.47 ± 2.95
t= 1.98 0.055
24 hrs. 78.74 ± 3.03
79.79 ± 2.49
t= 1.17 0.25
Data were presented as mean ± SD*significant **highly significant
0 1 2 6 12 2476
76.5
77
77.5
78
78.5
79
79.5
80
80.5
81
Group EGroup P
Fig.(5):-heart rate(bpm)
At 1hr post-operative, there was insignificant decrease in heart rate in
EPB group (p>0.05).
Also at 2hrs, there was significant decrease in heart rate in EPB group as
compared toPVB group (p=0.01).
At 6hrs, there was significant decrease in heart rate in EPB group
(p<0.05).
Heart rate showed insignificant decrease in EPB group as compared to
PVB at 12hrs post-operative (p>0.05).
67
At 24hrs, there was insignificant increase in heart rate in EPB group
(P=0.25).
Respiratory rate:- As regards respiratory rate (RR) in the two groups, current study showed
no statistically significant differences in RR between both groups as
51. Westlund N, Miller PF, Sheps DS, et al.(2007) The effect of age
on pain perception and nociceptors. Anesthesiology, 120: 22-30.
88
52. Weyman AE: ( 1994) Physical principles of ultrasound. In:
Weyman AE, ed.Principles and Practice of Echocardiography.
2nd ed. Media, PA: Williams & Wilkins;:3–28.
53. Wheeler, M., Oderda, G. M., Ashburn, M. A., & Lipman, A. G.
(2002) Adverse events associated with postoperative opioid
analgesia: A systematic review. Journal of Pain; 3(3), 159–180.
54. Zarzur, E. (1984). Genesis of the 'true' negative pressure in the
lumbar epidural space: a new hypothesis. Anaesthesia, Vol. 39, pp.
(1101-1104).
العربى الملخص
للألم الجسم بدايتها يستجيب فى تعد فسيولوجية بطريقةنافعةومفيدة.
اكلينيكيا يؤثر الجراحية العمليات مابعد معالجةآلام عدم كماأنمعدلات وزيادة زيادةالتكلفة إلى ممايؤدى المرضى على ونفسيا
. إلى أيضا كمايؤدى المزمنة الآلام حدوث نسبة وازدياد الوفاة , ذبحة حدوث بالأوردة الدم تخثر مثل السلبية الآثار من العديد
, , القلب, بعضلة الدم تجلط الرئوى بالشريان الدم تجلط صدرية. الأرق و الجروح التئام عدم و رئوى التهاب حدوث
مدة إطالة إلى يؤدى إذ الاقتصادية الناحية من سلبيا يؤثر أنه كماخروجه بعد المستشفى إلى المريض عودة أو بالمستشفى الإقامة
. له المقدمة الطبية الرعاية عن المريض رضاء عدم و منها
89
مع التعامل فى قصور وجود إلى حديثا أجريت دراسة أشارت وقدبين ما شدتها تتراوح التى و الجراحية العمليات مابعد آلام
. شديدة إلى متوسطة
: الدراسة من الهدفطريق عن التخدير فاعلية بين المقارنة إلى الدراسة هذه تهدفبجانب المستمر الحقن و الجافية الأم فوق المستمر الحقنتخفيف فى الصوتية فوق الموجات باستخدام القطنية الفقراتالحيوية العلامات استقرار و السفلى البطن عمليات بعد الألم
للمرضى.: البحث وطريقة المرضى
على الدراسة هذه فوق 38أجريت أعمارهم تم, 18مريض عامامنهما كل تحتوى متساويتين مجموعتين إلى عشوائيا تقسيمهم
مريضا :19على : الفقرات بجانب المستمر للحقن خضعت الأولى المجموعة) , إعطاؤها تم الصوتية فوق الموجات باستخدام مل)20-15القطنية
البيوبيفاكين عقار .0.5من أولية% كجرعة , : وتم الجافية الأم فوق المستمر للحقن خضعت الثانية المجموعة
البيوبيفاكين) 8-5إعطاؤها ( ر غقا من .0.5مل أولية% كجرعةعيار ( قسطرة وضع تم المجموعتين كلتا المستمر) 20في للحقن
/ 0.1بمعدل البيوبيفاكين/ عقار من ساعة كجم عقار% 0.125مل معبمعدل للتخدير/ 1الفنتانيل المريض إخضاع تم ثم مل ميكروجم
الكلى .ثم الكلى التخدير من المريض إفاقة تم الجراحية إنهاءالعملية بعد
العلامات لمتابعة الجراحية عمليات بعد ما الرعاية لوحدة نقل. المستمر الحقن استمرار مع لمدةساعتين الحيوية
عند الآتية المعايير قياس تم :24,12,6,2,1ثم الإفاقة بعد ساعة
90
1) لايوجد) صفر من تتراوح والتى البصرى بالمقياس الألم شدة( محتمل) ( غير ألم عشرة إلى ألم
خلال) 2 المسكنة المواد استهلاك ساعة24معدلالقلب) 3 ضربات ومعدل الدم ضغط متوسطالتنفس) 4 معدل
: البحث نتائجبالنسبة الدراسة مجموعتى بين واضح فرق وجود ملاحظة يتم لم
المسكنة المواد استهلاك أومعدل البصرى بالمقياس الألم لشدةساعة.24خلال
كانوا فقد القلب ضربات ومعدل الدم ضغط لمتوسط أمابالنسبة. الجافية الأم فوق حقنها تم التى المجموعة فى أقل
( , , ) كانت فقد البول احتباس القئ الغثيان للمضاعفات وبالنسبة. الجافية الأم فوق حقنها تم التى المجموعة فى أكثر أيضا
الجافية الأم فوق المستمر الحقن من كلا أن ذلك من ونستنتجمابعد لآلام فعال علاج القطنية الفقرات بجانب المستمر والحقن