New trends in regional anesthesia for shoulder surgery: Avoiding devastating complications
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Title: New trends in regional anesthesia for shoulder surgery: Avoiding devastating complications
Series Title: International Journal of Shoulder Surgery
Physical Description: Journal Article
Creator: Boezaart, Andre P.
Tighe, Patrick
Publisher: Medknow Publications
Publication Date: 2010
Copyright Date: 2010
 Notes
Abstract: Surgeons and patients are often reluctant to support regional anesthesia (RA) for shoulder and other orthopedic surgeries. This is because of the sometimes true but usually incorrectly perceived “slowing down” of operating room turnover time and the perceived potential for added morbidity. Recently, severe devastating and permanent nerve injury complications have surfaced, and this article attempts to clarify the modern place of RA for shoulder surgery and the prevention of these complications. A philosophical approach to anesthesiology and regional anesthesiology is offered, while a fresh appreciation for the well-described and often forgotten microanatomy of the brachial plexus is revisited to explain and avoid some of the devastating complications of RA for shoulder surgery.
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Rights Management: Permissions granted to the University of Florida Institutional Repository and University of Florida Digital Collections to allow use by the submitter. All rights reserved by the source institution.
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Full Text
ISSN 0973 - 6042


International Journal of


Shoulder Surgery


VolmISse 1 Ja-Mr 2 0i


Contents


> New trends in regional anesthesia for shoulder surgery: Avoiding devastating
complications

> Variation of tension in the long head of the biceps tendon as a function of limb position
with simulated biceps contraction

> A simple and safe technique for reconstruction of the acromioclavicular joint

> Metastasis from scapular Ewing's sarcoma presenting as sutural diastasis: An unusual
presentation

> Streptococcus subpectoral abscess with shoulder pain: A rare emergency with a
common symptom?


Online full text at
www.internationalshoulderjournal.org


Publishe byPublcat










Review Article



New trends in regional anesthesia for

shoulder surgery: Avoiding devastating

complications

Andr6 P. Boezaart1,2, Patrick Tighe1


ABSTRACT
Surgeons and patients are often reluctant to support regional anesthesia (RA) for shoulder
and other orthopedic surgeries. This is because of the sometimes true but usually incorrectly
perceived "slowing down" of operating room turnover time and the perceived potential for
added morbidity. Recently, severe devastating and permanent nerve injury complications have
surfaced, and this article attempts to clarify the modern place of RA for shoulder surgery and
the prevention of these complications. A philosophical approach to anesthesiology and regional
anesthesiology is offered, while a fresh appreciation for the well-described and often forgotten
microanatomy of the brachial plexus is revisited to explain and avoid some of the devastating
complications of RA for shoulder surgery.

Key words: Acute pain management, complications, continuous peripheral nerve block,
permanent nerve damage, regional anesthesia, shoulder surgery, upper limb surgery


www.internationalshoulderjournal.org


'DepartmenIts of4 Ansheiloy and 1


'Orhpeic Surgery3/0 Rehabilitation


INTRODUCTION

Every discipline in medicine has a basic fundamental truth
that it ascribes to. For example, for critical care medicine
(CCM), this truth is barrier integrity. In a healthy person, all
anatomical and physiological barriers are intact and functional.
These barriers are generally energy-dependent and keep
critical substances separated. Upon death, all these barriers
fail: fluid moves into the alveoli, bacteria move into the
blood stream, and sodium and potassium equilibrate across
cell membranes.

Anesthesia and regional anesthesia (RA) maintain their
own peculiar truth. Understanding this truth may promote
better understanding of what anesthesiologists instinctively
or knowingly strive to accomplish. At the very least, such
understanding may help the perioperative team to avoid some
common anesthetic pitfalls.


THE FUNDAMENTAL TRUTH OF
ANESTHESIOLOGY AND REGIONAL
ANESTHESIA

If CCM is about managing barriers, then anesthesia is about
managing reflexes. These can be physiological reflexes; if one
cuts the skin the patient reacts, if one places a tube in the
trachea, the patient reacts, and so forth until surgery would
be an exercise in frustration. During surgery and trauma, most
of the reflexes are initiated by nociception, or the noxious
stimuli resulting from surgery or trauma. Others are initiated
by hypovolemia and other stimuli, but this review will focus
on nociception and management of the reflexive response.

The physiological reactions to pain are vast and well known,
and vary from attempting to get up off the table and run away,
to an increased heart rate and blood pressure. These reflexes
can be managed at the end organ, for example by giving beta-


Pes cite this. . . . i as AP Tg . i i I J S l 2


1 Int J Shoulder Surg - January-March 2010 / Volume 4 / Issue 1 +







Boezaart and Tighe: New trends in regional anesthesia for shoulder surgery

blocking agents to counteract the hypertension and tachycardia
response to noxious stimuli. The use of muscle relaxants to
prevent the spinal cord-mediated reflexive movement to
nociception is another example.

A second place where this reflex to noxious stimuli can be
interrupted is in the central nervous system. Using potent opioids
such as fentanyl, alfentanil, remifentanil, and morphine to occupy
receptors throughout the brain and spinal cord usually minimizes
the reaction to such stimuli - a popular technique, perhaps, but
not without cost in the form of unwanted and unpleasant side
effects. Opioids bring with their administration the well-known
side effects of tolerance, nausea, constipation, and respiratory
depression, along with the lesser-known effects of possible
immune suppression1'1 and postoperative hyperalgesia.[23

Perhaps the optimal place to interrupt these noxious impulses
resides within the site of origin. Avoiding the painful stimulus
in the first place can do this, but this is unrealistic in a surgical
setting. Next best, then, is "hiding" the surgical stimulus from the
ever-vigilant spinal cord. Physicians can block the nociception
receptors from transmitting a message of pain to the brain by
injecting local anesthetic agents into the surgical field, or by
blocking the nerves that relay the message of pain to the spinal
cord and brain. That is the prime use of RA in modern practice.

In modern anesthesiology, it is no longer a situation of general
anesthesia (GA) versus regional anesthesia (RA). The out-dated
notion that RA is safer than GA does not hold true anymore.
Although literally thousands of research projects attempted
to demonstrate that RA is safer than GA, these efforts were
frustrated and consistently met with failure because the premise
is simply not true. For example, in 1954 the mortality associated
with GA was 3.7 per 1,000.41 That means that for every 1,ooo
patients induced with GA in 1954, 3.7 would die as a direct
result of the anesthesia. In 1982 that figure improved to a mere
1 per 1o,ooo anesthetics,b] and it did at that time make sense
to offer some alternative to GA. That was probably the reason
for the sharp increase in the use of RA over the last half of the
previous century. Now, in 2010, we can relax, GA is safe, and
has an associated mortality rate of approximately 1:300,ooo.[6]
We can now focus our energy on the appropriate management
of pre-, intra-, and postoperative pain. RA is perfectly suited
for this, because it is very effective, safe (if the time-tested
rules are obeyed), can be administered preoperatively, used for
intraoperative analgesia and continued through the postoperative
period.

Modern anesthesiology, therefore, is all about managing reflexes
associated with surgery, and to disrupt the pathway of the
noxious stimulus to the brain makes perfect sense. This is the
modem use of RA. In the postoperative period, RA provides
excellent analgesia, while minimizing opioid-related side effects
by reducing and even eliminating the need for opioids. RA has
proven its value as the ultimate weapon in the armamentarium
of multimodal approaches to postoperative pain.

+ Int J Shoulder Surg - January-March 2010 / Volume 4 / Issue 1


SINGLE-INJECTION VERSUS CONTINUOUS
NERVE BLOCKS

Single-injection nerve blocks are well suited as the sole
anesthetic for peripheral surgery such as to the hands, feet, and
eyes under monitored anesthetic care (MAC) conditions and
various degrees of sedation - from conscious to unconscious
sedation. However, single injection nerve blocks have a short
duration of action and are only of value for the intraoperative
and direct postoperative period. In a very painful surgical
procedure, such as rotator cuff repair, single-injection nerve
block may be valuable in managing the intraoperative pain.
Such nerve blocks even help in getting the patient out of the
recovery room expeditiously.71 Unfortunately, the patient
receiving a single-injection nerve block for rotator-cuff repair
is the same unfortunate soul waking at 0200 with severe,
uncontrolled, and unmanageable pain in the dark and loneliness
of the night. Most surgeons, and especially patients, would
agree that in this situation it would probably have been better
to have no block and to manage the pain with conventional
analgesics before discharging the patient from the hospital or
surgical center.

If, therefore, the patient is expected to suffer severe
postoperative pain, it is the modern trend to place a continuous
nerve block preoperatively. The anesthesiologist injects a bolus
through the perineural catheter sufficient for an intraoperative
surgical block, and then infuses a low concentration and volume
of local anesthetic through the perineural catheter for a few
days following the surgery.[8] However, ambulatory continuous
nerve block requires continuous and costly involvement of
healthcare professionals, and not all anesthesiologists are willing
to spend such energy to add this liability without suitable
remuneration. The question of who takes responsibility for
the cost associated with ambulatory continuous nerve blocks
has been unanswered, and some argue that the benefits are
not worth the cost and effort. Although such systems are
feasible, effective, and met with a high level of patient and
surgeon satisfaction, 9-11 ambulatory continuous peripheral
nerve blocks have unfortunately not yet reached their rightful
place, except in the practices of a small number of enthusiastic
anesthesiologists.

There is very little doubt that continuous nerve block is
advantageous for in-patient care of patients, especially elderly
patients, who require total joint replacement. Indeed, physicians
seem to agree; 89% of French anesthesiologists would request
a regional anesthetic for their own surgery, if the procedure
were amenable to such a block.[12] Continuous nerve block has
no place for relatively painless surgery such as carpal tunnel
release and acromioplasty.['31 Here, the patient is burdened with
the risks of a perineural catheter, whereas enjoying no benefit
over single-injection nerve blocks or simple field block, which
may be advantageous for these surgeries.

Is it possible to enjoy the prolonged analgesia of a perineural









catheter, but absorb only the risk of a single-injection nerve
block? Some workers have promoted the use of additives such
as buprenorphine to the local anesthetic agent to extend the
duration of action,E41 but this has not universally been met
with enthusiasm. It is, generally, felt that if a long-acting block
is needed a catheter should be placed for continuous nerve
block, which is regarded by most as safer (or at the very least
as safe) as single-injection blocks with fewer unwanted side
effects or complications.

Why this apparent contradiction? With increasing
concentrations of local anesthetics, nerves are generally blocked
in the following order: pain fibers, then general sensory, and
then motor.['51 The ideal local anesthetic would provide intense
motor (also referred to as "surgical") blockade during the
intraoperative period. Shortly thereafter, the block's intensity
would decrease to cover only pain fibers, thus permitting full
participation in rehabilitation while maintaining a pain- and
opioid-free recovery. This pain-fiber coverage would last for 3
to 7 days before resolving completely, and the physician would
have a mechanism for concluding the nerve block prematurely
if clinically indicated.

Current mechanisms used to prolong single-injection nerve
blocks do so by extending the entire "pharmacokinetic" profile
of the nerve block. That is, each stage of motor, sensory, and
analgesia block is prolonged. Prolonged motor, and even sensory,
blocks run several risks, including suboptimal participation in
rehabilitation, as well as neurapraxic injuries stemming from
limb malpositioning unnoticed by patients in the days following
surgery. In contrast, the properly managed perineural catheter
permits intense surgical blockade during the intraoperative
period, and then titratable analgesic-level nerve blockade for
days thereafter, with the option of discontinuing the nerve
block effect at any point. This has not been fully clarified
by research, but at the very least, it can be accepted that
continuous nerve block is as safe and free of side effects as
single-injection nerve block.

Drug companies have also worked energetically for at least the
past 15 years to develop a long-acting local anesthetic agent,
but this cannot expect to be successful for anything but local
wound infiltration, because similar to extended release epidural
morphine, it is not only the wanted effects of analgesia that is
long-lasting, the unwanted side effects, for example, phrenic
nerve paralysis, will also be long-lasting. For those reason
catheters for long-term nerve block are, for the time-being at
least, here to stay.

SEVERE NEUROLOGICAL COMPLICATIONS

One unpublished case of a young professional that permanently
lost the function of the superior trunk of the brachial plexus
(personal communication), and a number of unpublished cases
of quadriplegia and at least two published reports of spinal cord
injury�'1 brought this issue acutely to the forefront.


Boezaart and Tighe: New trends in regional anesthesia for shoulder surgery

Radiating pain upon removal of a continuous
nerve block catheter
The patient who lost the function of his superior trunk received
an ambulatory continuous interscalene block for a rotator cuff
repair. Upon removing the catheter at home the day after
surgery, he experienced severe pain that radiated down his
arm, which he described as a "lightning bolt going down his
arm." The anesthesiologists reassured him and he continued to
remove the catheter, which ended with total and permanent
loss of the fifth and sixth roots of the brachial plexus.

The catheter was advanced 15 cm beyond the tip of the
needle, and was clearly curled around the superior trunk of
the brachial plexus. Upon removal of the catheter, the nerve
roots were avulsed, which caused the "lightning bolt" sensation
experienced by the patient followed by the permanent nerve
injury and loss of function.

We therefore strongly propose the following protocol for
catheter removal:
* We do not condone the "bolus and pull" practice of some
practitioners.
* Removal of a catheter can only take place when the
sensation and motor function have fully returned to the
limb.
* If there is no pain with removal of the catheter, it can safely
be removed.
* If there is radiating pain, fluoroscopy with contrast of the
plexus should be undertaken. Ultrasound examination of
the brachial plexus could also be done, and, under both
scenarios if light tugging on the catheter causes the brachial
plexus to move with the catheter, surgical removal of
the catheter is mandatory. If the brachial plexus does not
move with the tugging on the catheter, the catheter can
be removed carefully.

Surgical removal should be an extremely rare occurrence, but
if indicated one should not hesitate to do it. With the modern
recommendation of not advancing catheters further than
3-5 cm beyond the needle tip, it can be expected that this
phenomenon will disappear.

Spinal cord injury
Voermans et aL highlighted this problem.[16 Unfortunately, it
is the humble opinion of the current authors that this problem
could be expected to increase as the use of ultrasound increases.
It is a fact that the brachial plexus is best visualized when the
ultrasound probe is placed perpendicular to the nerves with the
scalene muscles and nerves in the short axis of the ultrasound
beam.['71 It is also a fact that the in-plane approach to these
nerves is the easiest way to perform a brachial plexus block.['8*91
This leads to the so-called "posterior approach to the brachial
plexus," which is similar to the Pippa approach popular in
Europe.12o1 This, unfortunately, often leads to the block being
done more medially and on the root level of the brachial plexus.

3 Int J Shoulder Surg - January-March 2010 / Volume 4 / Issue 1 +







Boezaart and Tighe: New trends in regional anesthesia for shoulder surgery

This root-level approach provides an excellent analgesic block,
but it is not readily appreciated that at this level the roots are
surrounded by dura and penetration of the dura leads to a
subdural injection, which can also be intramedullary, because
the nerve tissue here is nothing but the axons originating in
the spinal cord, which are accompanied by perineural spaces
in which the local anesthetic agent spreads centrally. Both
these scenarios can of course lead to devastating complications
and preventing these can only be done if the microanatomy
of the brachial plexus is fully understood. A review of this
microanatomy follows.

MICROANATOMY

Our understanding of the microanatomy of the peripheral
nervous system is not new. Key and Retzius211 in 1876 used
Richardson's stain, whereas Horster and WhitmanE2] in 1931
used trypan blue to study the spread of intraneurally injected
solutions experimentally. In more "recent" times, French
et al. in 1948E[31 studied intrafascicular injection with radiopaque
contrast medium in dogs. Since this early work, even after the
introduction of electron microscopy,[41 no new insights have
been introduced to refute these concepts or add significant
new knowledge.

Peripheral nerve microanatomy
The embryological formation of the branches or peripheral
nerves occurs later than roots and trunks, but for ease of
understanding, the peripheral nerves will be considered first.
Peripheral nerves are composed of numerous fasciculi; each
surrounded by a dense perineurium and held together by a
looser epineurium [Figure i].

The epineurium consists of a condensation of areolar connective
tissue that surrounds the perineurial ensheathment of the
fascicles of uni- and multifascicular nerves.E251 The attachment
of the epineurium to surrounding connective tissue is loose,
so that the nerve is relatively mobile except where tethered


Figure 1: Microanatomy of a peripheral nerve


by entering blood vessels or by branches.E251 Greater amounts
of connective tissue are normally present where nerves cross
the joints. In general, the more fascicles that are present, the
greater the quantity of epineurium. Variable quantities of fat
in the epineurium have a protective function in cushioning
the fascicles against injury,E[51 and the vasa nervorum enter
the epineurium, where they communicate with a longitudinal
anastomotic network of arterioles and venules.[251

The epineurium also contains lymphatic vessels, which are
not present within the fascicles. These lymphatic channels
accompany the arteries of the peripheral nerves and pass into
the regional lymph nodes.[251

The essential structure of the perineurium is a lamellated
arrangement of flattened cells separated by layers of
collagenous connective tissue (similar to the plexus sheaths
and, although not yet shown, one wonders if the epineurium
is not a continuation of the plexus sheaths).[1] It provides an
ensheathment for both the somatic and peripheral autonomic
nerves and their ganglia. The cellular lamellae are composed of
concentric sleeves of flattened polygonal cells, and these cells
are equipped to function as a metabolically active diffusion
barrier, although they do not have the morphologic features
of a true epithelium.

The term endoneurium is sometimes erroneously used to denote
the intrafascicular compartment of the nerve; it should only
be used to refer to intrafascicular connective tissue, excluding
the perineurial partitions that may subdivide fascicles.[251
Approximately 40-50% of the intrafascicular space is occupied
by non-neural elements and about 20-30% of this is the
endoneural fluid (CSF) and connective matrix (endoneurium).251

Longitudinal flow within the fascicle is inhibited minimally,
whereas lateral extension is restricted by the relatively non-
compliant perineurium.[251 As the nerve approaches the dural
penetration, resistance to extension increases and a peripherally
injected medium comes to lie in clefts in the perineurium. Final
emergence into the subarachnoid space occurs first by way of
the subdural space and subsequently by breakthrough across
the arachnoid barrier into the subarachnoid space.

A fluid deliberately or accidentally injected into a fascicle
of a peripheral nerve has direct access to the cerebrospinal
fluid (CSF) and interstituim (medulla) of the spinal cord, and
such spread depends directly on the volume and pressure
applied.261 The channels by which this progression occurs have
been called perineurial spaces, and these have been previously
demonstrated. 261 Injection into a spinal root, on the other hand,
is easy, and this injectate, similarly has direct access to the
CSF and spinal cord interstitium - the clinical consequences
of which depends on the volume, rate, and pressure of the
injectate and the path taken via the perineurial spaces of the
axons. The injectate will generally follow the route of least
resistance via these perineural spaces.[261


+ Int J Shoulder Surg - January-March 2010 / Volume 4 / Issue 1









Experimental work of Selander and Sj6strand on intraneural
injections into rabbit sacral nerves demonstrated that, during
injection deep to the epineurium but outside the perineurium,
an irregular bleb formed around the injection site.[251 The
tracer that they injected spread for a short distance within an
easily expanding epineurium, which often ruptured. When
50-100 pL were injected at ioo pL/min, the injection pressure
rose within a few seconds to 30-60 mmHg and thereafter
quickly decreased to a steady 10-30 mmHg. As soon as the
injection stopped, the pressure returned to zero. During
intrafascicular injection deep to the perineurium, however,
the tracer was seen to spread rapidly, proximally, and distally
inside the fascicle. The longitudinal spread varied, but in all
cases, it reached the sacral plexus. Distally, the tracer colored
the tibial nerve, sometimes even reaching the foreleg. In
another study,[231 the tracer reached the lumbar plexus via the
injected fascicle, and then even sometimes tracked distally via
an entirely different nerve originating from the plexus. This
study also showed that high-pressure intrathecal injection of
contrast medium spread down the fascicles of peripheral nerves.

Selander et al.26] demonstrated that if the injection was made
into a small fascicle, the injectate did not extend beyond
the sacral plexus, but if the injection was made into a big
fascicle, the injectate easily passed the sacral plexus and
reached the spinal cord. During slow injection, the spread in
the medulla was superficially under the pia mater. In some of
the experimental animals, the spread was into the CSF, and
the dura and arachnoid were also colored. In one animal, the
blue stain extended to the cerebellum. In cross sections of the
spinal cord, the fluorescent tracer used was mainly seen is the
thin sub-pial space.[J6] Accumulation of the tracer was noted
in the dorsal root-medulla junction area, extending into the
substantial gelatinosa of the anterior horns, and into the anterior
median fissure. They recorded pressures of between 435 and
675 mmHg when injecting 50-o0o pL with a rate of loo pL/
min into a fascicle. After cessation of the injection, the pressure
remained above the estimated capillary perfusion pressure


Figure 2: Microanatomy at the brachial plexus trunk level


Boezaart and Tighe: New trends in regional anesthesia for shoulder surgery

(50 mmHg) for at least to min.

Plexus trunk microanatomy
The trunks of the plexuses are transitional areas [Figure 2].23]
The perineurium surrounding the fascicles split away and axons
are separated by perineurial sheath interdigitations or septae.
There seems to be inter-individual variation on the level at
which the septae form, but functionally and practically from
a RA perspective, the trunks should be regarded as transitional
areas between clearly defined fasciculi with rigid perineuria at
the branches to the root area where perineuria are not present
and all the perineuria have joined to form the dura.231

Plexus root microanatomy
After splitting away from the fascicles, at the level of the
nerve roots, the perineurium thickens and fuses with the dura
[Figure 3].13'51] (Embryologically more correct, the peripheral
nerve perineurium is a continuation of the dura mater). The
axons inside the roots are consequently not protected by the
perineurium anymore and the extracellular or tissue fluid is
the CSF The connective tissue framework of the peripheral
nervous system, therefore, arises entirely from the dura mater
to a continuation of the perineurium around the fascicles of
the branches. As the nerve progresses peripherally, it is more
and more subdivided by perineural interdigitations until each
fascicle of nerve axons eventually has its own perineurial sheath.
The mesothelial cells of the arachnoid membrane become
hyperplastic where they exit the nerves and form a cuff around
the roots just after they penetrate the dura mater.[251 Beyond
this cuff, no tissue can be seen that is recognized as arachnoid.

Ultrasound
With the recent introduction of ultrasound to regional
anesthesia, it became clear that nerves could either be hyper-
or hypo-echoic.[17 When studying the ultrasonographic
appearance, it can be seen that the more proximal the nerve
the more hypo-echoic (black appearance) [Figure 4] and the


Figure 3: Microanatomy at the brachial plexus root level


5 Int J Shoulder Surg - January-March 2010 / Volume 4 / Issue 1 +







Boezaart and Tighe: New trends in regional anesthesia for shoulder surgery


Figure 4: Ultrasound picture at the brachial plexus root level. Note
root appears hypo-echoic

more distal, the more hyper-echoic the nerve ("honeycomb"
appearance) [Figure 5]. With the insight of the nerve
microanatomic morphology, this should be easy to understand
in practical terms - even if not entirely correct in pure physics
terms [Figures 4 and 5].

Intraneural injection
Although intraneural but extra-fascicular injection at the
branch level is probably without consequences,E[71 injections
at the root level (and perhaps trunk level of some individuals)
should be regarded as epidural injections, because the injection
is made directly outside the dura-extra-dural, peri-dural, or
epidural.E281 All the time-tested safety practices for spinal
epidural injections should therefore similarly apply for root
level or paraneuraxial or paraspinal extra- or epidural injections.
These should include the use of large bore relatively blunt
Tuohy needles and the avoidance of sharp thin needles (for
continuous and_single-injection blocks)[28]; the use of similar
test doses to test for intravascular or intrathecal injection,
fractionation of the main dose, and perhaps even similar
guidelines for anticoagulation, although this is open to debate
and can be expected to be further contested.E[91 All the
catastrophic, potentially catastrophic, and tragic cases, ranging
from total spinal block to quadriplegia, referred to in the papers
by Antonakakis et al.['8] and Mariano et al.[19 can comfortably
be explained by intraroot (sub-dural) injections with relatively
thin and sharp needles that were not designed for use around
the dura. All the presented cases were spinal root or trunk level
blocks[3o performed with needles that one would not use for a
spinal epidural block. All root level blocks (cervical, thoracic,
lumbar, and sacral), and perhaps even trunk level blocks, such
as interscalene blocks in certain individuals,b[30 should probably
be regarded and respected as para-spinal or para-neuraxial
epidural blocks similar to spinal epidural or neuraxial blocks
to afford it the appropriate level of respect that will avoid
disastrous complications.

+ Int J Shoulder Surg - January-March 2010 / Volume 4 / Issue 1


Figure 5: Ultrasound appearance of the femoral nerve - a peripheral
nerve. Note the nerve appears hyper-echoic

CONCLUSION

Modern anesthesiology should be regarded as the science of
managing reflexes. The reflexes following noxious surgical
stimuli can and should be managed at its origin rather than
at its end organ response. In this regard, RA plays a pivotal
roll in managing the reaction to intraoperative painful stimuli
by preventing it from reaching the spinal cord and brain.
Postoperatively, RA is also of great value to treat pain following
surgery and trauma and to minimize the use of opioids.

It is clear that institutions benefits greatly from single-injection
nerve block for postoperative pain management, and it is
also clear that, except for the practices of a few dedicated
enthusiasts, ambulatory continuous nerve block is highly
beneficial to patients, but the logistical and financial aspects
of it is far from solved.

Severe and permanent nerve injuries have been forced to the
forefront, but with careful catheter removal after full sensation
has returned to the limb and with full understanding and
respect for the microanatomy of the peripheral nervous system,
these complications can and should be nullified. This article
attempted to highlight the modern philosophical approach to
anesthesiology for shoulder and other surgeries, and attempted
to offer a practical approach to catheter removal to minimize
or nullify nerve injury. Finally, it attempted to revisit the
microanatomy of the brachial plexus, to caution practitioners
of the microanatomical reasons for devastating complications.

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Source of Support: Nil, Conflict of Interest: None declared.


7 Int J Shoulder Surg - January-March 2010 / Volume 4 / Issue 1 +




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