REGIONAL ANESTHESIA: TREATMENT MODALITIES AND PRACTICAL
SUGGESTIONS
From Slepless in Seattle, Hold the Mayo: Regional Anesthesia 2006, presented by Virginia Mason Medical Center
and the Mayo Clinic, August 4-6, 2006
| NEW MODALITIES FOR THE TREATMENT OF BACK PAIN —James P. Rathmell, MD, Director, Massachusetts
General Hospital Pain Center, Department of Anesthesia and Critical Care, and Lecturer on Anesthesia, Harvard
Medical School, Boston, MA
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| Common causes of low back pain: lumbar spine pain common in active population; usually acute dynamic overload
in younger population, and chronic repetitive exertion in older population; most people develop back pain, but first
episode usually self-limited; lifetime recurrence rate high
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| Pathophysiology: epidural steroid injection for radicular pain on same continuum as pain treatment for lumbar interbody
fusion (ie, lumbar degenerative disease); affects spinal segment, including discs and vertebrae; segmental
dysfunction (nucleus pulposus begins to lose hydration and disc height) results in more anterior and posterior
laxity; becomes more pronounced as disc height lowers (in third through fifth decades of life; varies depending
on occupation and genetic predisposition); in later decades, pain declines and back becomes stiffer; clinical correlates
include axial pain (lumbar strain syndrome) with or without radicular pain; gradually resolves over time
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 | Third and fourth decades of life: radicular pain due to degeneration of outer anulus; lateral protrusion of nuclear
material can cause impingement on, or inflammation around, nerve root; axial pain caused by tear in outer annulus;
“pop” in low back occurring after picking up heavy object may result in severe muscle spasm in following
days, without radicular pain; likely small tear in outer anulus that never impinges on nerve root; “not a lot of inflammation”;
also can protrude completely, leading to radicular pain
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| Sixth through eighth decades of life: almost complete loss of disc height, loss of hydration of central nucleus, and degenerated
outer anulus; no distribution of load causes increased bony deposition and end plate sclerosis; same process
of degenerative joint disease (calcium deposition) seen on facet joints (may occur anteromedially); stenosis of
canal manifests as radicular pain (gradual onset in elderly patient); may have severe stenosis at multiple levels, but
only one symptomatic (responds to steroid injection); stenosis of central canal can lead to symptoms similar to
neurogenic claudication due to central spinal stenosis; axial pain declines and stiffness increases; radiographic
changes could explain pain, but majority of patients do not have pain (<10% have ongoing back pain)
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| Discs: end plate fracture (axial pain) or minor fissures in outer anulus; usually heal, but also can cause acceleration
of disc degeneration; as disc degradation continues, isolated degradation occurs and may be painful; path of least
resistance leads to protrusion of nuclear material; causes inflammation around nerve root and radicular symptoms
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| Treatment: acute axial back pain—usually conservative management; epidural steroid probably has no role; acute
radicular pain—great degree of inflammation; epidural steroid useful (provides more rapid resolution of pain);
chronic radicular pain—probably neuropathic; ≈10% of discectomies have element of neuropathic pain;
chronic axial back pain—among most difficult and most common; causes include facet joints and discs; additional
comments—conservative management useful in majority; give mild analgesics for pain relief; muscle relaxants
useful for first 7 to 14 days; physical therapy useful to teach good body mechanics and to avoid
subsequent injury; diagnostic imaging done in most cases, but of limited use; lumbar epidural steroids can be
given without diagnostic imaging to accelerate resolution of pain; surgical intervention used for bilateral symptomatology,
progressive neurologic deficits, or signs or symptoms of cauda equina syndrome (eg, early urinary
retention, loss of bowel or bladder control, saddle anesthesia, hypesthesia); injection into epidural space in patient
with large space-occupying lesion acutely worsens cauda equina syndrome
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| Radiographic guidance: contrast material may not spread to needed areas; not known whether outcomes improved
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| Transforaminal injection of steroids: trials suggest efficacious for treating radicular pain (radiographic guidance
used in studies); problems include catastrophic neurologic injuries (vertebral artery injections causing cerebellar
infarctions [often with brainstem herniation and death] or cervical cord infarctions with quadriplegia); small arterial
branches directly supply spinal cord; arteries located near nerve root; anastomose with vertebral circulation;
particulate steroid injected into artery unknowingly, flows to endarterial circulation (either in cerebellum or spinal
cord), and causes infarction; catastrophic outcomes also possible down to lumbar spine area; use of live fluoroscopic
technique should avoid catastrophic outcome; controversy over performing interlaminar technique
exclusively (particularly in cervical area) vs transforaminal technique
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| Axial back pain: common; limited to lumbosacral junction; pain generators include facet arthropathy, degenerative
disc disease, and sacroiliac arthropathy (difficult to differentiate); unlikely to occur in isolation; most are combination,
with one pain generator predominating
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| Lumbar facet syndrome: known for decades; causes axial back pain (typically worsens with extension); radiographic
evidence of facet arthropathy not always present; young patient with severe facet pain typically has no
physiologic changes (rely on clinical diagnosis); severe pain occurs over facet joints; injecting joint with irritant
results in mild diffuse pain in nondermatomal distribution that may extend below knee
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| Radiofrequency neurolysis: creates small area of tissue destruction at particular depth; uses radiofrequency-range
energy; produces lesion of predictable size; includes direct and alternating currents; lesion varies, depending on impedance
of host tissue (in soft tissue, large lesion; in, eg, periosteum, small lesion); typically, 22-gauge spinal needle,
insulated to tip (excluding last 5 mm), and submerged in egg lecithin; originally developed for spinal cord
lesions and percutaneous cordotomy; denervates facet joints when placed next to peripheral innervations of facet
joint (nerves located based on radiographic anatomy); necessary to treat 2 levels to denervate 1 joint; moderate evidence
(level 2) that radiofrequency denervation more effective than placebo; safe technique; placed anatomically
and tested physiologically to avoid major motor nerve; 50% pain reduction in 50% to 75% of patients; duration ≥3
mo (median duration 3-6 mo); probably more effective for cervical pain (eg, following whiplash injury)
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| Minimally invasive discectomy: place needle in disc and pressurize single disc; ask patient whether pain reproduced
(subjective test); use low volumes and low pressures; pain provocation most important; injecting adjacent disc
should not be painful; not known whether technique can determine pain generators; consensus statement indicates
usefulness for assessing discs before fusion and for assessing patient before minimally invasive surgery; prospective
observational studies suggest discography can better predict who will respond to fusion; minority of pain-related
applications for this type of fusion; more common indications for fusion include degenerative spondyloschisis
and increasing pain over time
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| Intradiscal electrothermal therapy (IDET): introduced in ≈1999; developed by 2 physiatrists; heated wire placed
along posterior anular wall; used to shrink collagen fibers, cauterize granulation tissue, and coagulate nerve tissue
penetrating anulus; studies show no complications or adverse effects; 50% improvement in functional status (and
pain [secondary outcome]) in >50% of patients; useful for patient with early degenerative disc disease, good preservation
of disc height, and axial back pain at 1 level only (≤10% of patients); complications include catheter kinking
and threading through radial tear into epidural space causing damage to cauda equina; safe only in awake
patient; not to be used for disc herniation (does not decrease pressure or volume in disc)
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| TRICKS OF THE TRADE —Michael F. Mulroy, MD, Faculty Member, Department of Anesthesiology, Virginia
Mason Medical Center, Seattle, WA
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| Introduction: regional blocks not always effective, particularly when attempting new technique; must gain experience
and expertise; learning curve part of process; surgical colleagues perceive regional blocks to “take longer”
(may appear to waste time and delay surgery); important to consider ways to reduce amount of time required to
place regional block (thereby increasing acceptance)
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| Prepare outside operating room (OR): “the more you can externalize that work outside the OR, the more successful
you’re going to be” in placing blocks on time, getting good solid block, and having high surgical acceptance;
have patient arrive at preanesthesia clinic in advance of surgery; explain block and procedure, and answer
questions (reduces anxiety on day of surgery [patient knows what to expect]); if no preanesthesia clinic available,
call patients on day before surgery; review history, anesthetic needs, and explain anesthetic plan
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| Find work space: trying to do blocks in OR (particularly peripheral nerve blocks that have longer “soak” times and
often longer procedural times) fraught with peril; creates impression of delay in minds of other OR personnel;
while acceptable to place spinal anesthetic in OR (usually can be placed quickly and has fast onset), most other procedures
(eg, epidural, peripheral nerve block) require extra time, so need “surgeon-free zone”; new construction
should include architectural plan for anesthesia work space to place blocks; in most settings at speaker’s institution,
induction room for anesthesia also used as admitting area; sometimes just corner of postanesthesia care unit
(PACU) will suffice (usually equipped with monitors and resuscitation devices); important to have extra 10 to 15
min to obtain anesthetic level before taking patient to OR; data show that if block done in induction area, anesthesia
time in OR reduced (particularly if shoulder surgery)
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| Have equipment readily available: keep all supplies needed to perform block (including anesthetics) located on mobile
cart, to avoid having to search for equipment at critical time
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| Get help: at least one other person necessary; speaker’s practice commonly uses attending physician, resident, or
nurse anesthetist; in private practice setting, many PACU nurses interested in regional anesthesia (desire that patient
leave OR without pain or nausea); often willing to help with blocks and manipulation of nerve stimulator
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| Anticipate potential problems: anesthesia provider currently faced with more obese patients (difficult to palpate
landmarks, find interscalene groove); use more reliable landmarks (eg, bones, arteries, tendons) to identify location
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| Choose blocks that are simple and easy to perform: “pick something that makes sense for you and that you’re comfortable
doing with the landmarks and the technique that’s described, and get good at it”; simple and familiar
techniques can be done quickly and easily with high degree of reliability; also important that technique compatible
with surgery; prepare in advance; give sedation to get cooperation (too much in outpatient setting, however,
may delay discharge); speaker adds fentanyl to avoid perception of painful needle injection; landmarks —look
for easily produced, reproduced, and findable landmarks; tubercle easier to feel than interscalene muscles; same
true for other blocks associated with axillary and femoral arteries; subgluteal parabiceps approach to sciatic
nerve
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| Search logically: search perpendicular to presumed path of nerve; limit search to 1 plane; small change in angle of
needle results in large change in location of needle tip (avoid parallel search)
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| Use external tools to help localize landmarks: speaker uses Doppler ultrasonography device in PACU to identify
axillary and femoral arteries; paresthesia technique useful for experienced anesthesia provider; allows precise localization;
nerve stimulator “kind of tells you when you’re getting close”; in axillary block, also gives useful information
about location above or below artery; speaker uses nerve stimulator for most blocks, particularly when
teaching residents (additional advantage of painless localization for patient); ultrasonography newest tool available
and excellent for identifying nerves for superficial blocks; however, technology expensive and involves
learning curve (not as useful for deep nerves)
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| Be flexible: be able to change plans; saves time; accomplishes goal of getting block done
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| Choose fast-acting drugs: addition of sodium bicarbonate to either lidocaine or mepivacaine increases time to onset
by 2 to 5 min; unfortunately, does little to speed onset of bupivacaine; speaker does not use sodium bicarbonate for
postoperative pain control; just uses for axillary block with short-acting amino amide (but not longer-duration
drugs); 2-chloroprocaine (spinal) provides fast onset, predictable dense anesthesia, and predictable offset (use only
preservative-free solution in brown bottle); discharge times with 2-chloroprocaine competitive with sevoflurane
and propofol general anesthesia
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| Limit failures: improve success rate by being prepared (several web sites available, eg, www.asra.com); “don’t give
up” (study of trainees found 20-45 attempts required for proficiency in administering spinal and epidural blocks);
when failures occur, “don’t publicize them” (avoid delaying surgery); make injection and move to OR with confidence;
if in doubt, give propofol, fentanyl, and place laryngeal mask airway (LMA), if necessary; “nobody in the
room, except you, should know that the block is not working”; do not delay surgery, make surgeon wait, or redo
block while in OR (unless absolutely essential); remind surgeon of successes
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Suggested Reading
Andersson GB et al: Intradiscal electrothermal therapy (IDET). Spine 31:1402, 2006; Appleby D et al: Meta-analysis
of the efficacy and safety of intradiscal electrothermal therapy (IDET). Pain Med 7:308, 2006; Armstrong KP et
al: Brachial plexus anesthesia compared to general anesthesia when a block room is available. Can J Anaesth 51:41,
2004; Bogduk N et al: The cervical zygapophysial joints as a source of neck pain. Spine 13:610, 1988; Bogduk N: A
narrative review of intra-articular corticosteroid injections for low back pain. Pain Med 6:287, 2005; Bogduk N:
Pharmacological alternatives for the alleviation of back pain. Expert Opin Pharmacother 5:2091, 2004; Capogna G
et al: Alkalinization of local anesthetics. Which block, which local anesthetic? Reg Anesth 20:369, 1995; Derby R et
al: Efficacy of IDET for Relief of Leg Pain Associated with Discogenic Low Back Pain. Pain Pract 4:281, 2004;
Hoeft MA et al: Cervical transforaminal injection and the radicular artery: variation in anatomical location within the
cervical intervertebral foramina. Reg Anesth Pain Med 31:270, 2006; Rathmell JP et al: Cervical transforaminal injection
of steroids. Anesthesiology 100:1595, 2004; Rathmell JP et al: Infectious risks of chronic pain treatments: injection
therapy, surgical implants, and intradiscal techniques. Reg Anesth Pain Med 31:346, 2006; Rathmell JP et al:
The role of intrathecal drugs in the treatment of acute pain. Anesth Analg 101:S30, 2005; Rathmell JP et al: Transforaminal
injection of steroids: should we continue? Reg Anesth Pain Med 29:397, 2004; Rathmell JP: Imaging in regional
anesthesia and pain medicine: we have much to learn. Reg Anesth Pain Med 27:240, 2002; Riew KD et al:
The effect of nerve-root injections on the need for operative treatment of lumbar radicular pain. A prospective, randomized,
controlled, double-blind study. J Bone Joint Surg Am 82-A:1589, 2000; Vad VB et al: Transforaminal epidural
steroid injections in lumbosacral radiculopathy: a prospective randomized study. Spine 27:11, 2002.
Educational Objectives
| The goal of this program is to improve the treatment of back pain and improve effectiveness of regional anesthesia in
clinical practice. After hearing and assimilating this program, the clinician will be better able to:
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| 1. Recognize common causes of low back pain.
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| 2. Explain the pathophysiology of back pain.
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| 3. Identify the variety of treatment options for low back pain, including transforaminal injection of steroids, radiofrequency
neurolysis, minimally invasive discectomy, and intradiscal electrothermal therapy.
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| 4. Efficiently externalize the work involved in potential regional block cases.
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| 5. Make regional anesthetic blocks easier and applicable to many techniques.
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Faculty Disclosure
In adherence to ACCME Standards for Commercial Support, Audio-Digest requires all faculty members to disclose
relevant financial relationships within the past 12 months that might create any personal conflicts of interest. Any
identified conflicts were resolved to ensure that this educational activity promotes quality in health care and not a proprietary
business or commercial interest. For this program, the following has been disclosed: Dr. Rathmell has received
research funding from Cephalon, Arthrocare, and Ortho-McNeil, and is a member of the advisory board for
Ortho-McNeil.
Acknowledgements
Drs. Rathmell and Mulroy spoke at Sleepless in Seattle, Hold the Mayo: Regional Anesthesia 2006, held August 4-6,
2006, in Seattle, WA. The Audio-Digest Foundation thanks the speakers, Virginia Mason Medical Center, and the
Mayo Clinic for their cooperation in the production of this program.
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