NMCSD Pain Medicine Research Initiatives

Steven R. Hanling, M.D.Assistant Clinical Professor

Department of Anesthesiology/Pain MedicineUniformed Services University of the Health Sciences

Anesthesia Department Naval Medical Center San Diego

Steven R. Hanling, M.D.Assistant Clinical Professor

Department of Anesthesiology/Pain MedicineUniformed Services University of the Health Sciences

Anesthesia Department Naval Medical Center San Diego

TOPICS

• Phantom Limb Pain– Mirror Therapy

• Low Back Pain– Biaculoplasty vs Fusion– Return to Duty Rates

Background

• Phantom Limb Sensation– Perceived sensation of

amputated limb– Phantom Limb Movement

• Phantom Limb Pain (PLP)

• Stump Pain

Background

• Incidence of phantom limb pain

– 72% after limb amputation

– May be higher if pre-existing painful condition

– Appears immediately in 75% of patients

– May be delayed a few weeks in 25%

Historical Perspective

• First reported in 16th Century

• French military surgeon Ambroise Pare (1552)

– faux sentiments

– la douleur es parties amputees

Fortschr Med. 1990 Feb 10;108(4):62-6.[So-called initial description of phantom pain by Ambroise Pare. "Chose digne d'admiration et quasi incredible": the "douleur es parties mortes et amputees"]

Historical Perspective

• Still not “believed” as late as 1980’s

• 700 US Vets surveyed

• 85% incidence --> 61% discussed with physician

• 17% treated

• Remainder told MENTALLY DISTURBED

Sherman and Sherman. Prevalence and characteristics of chronic phantom limb pain among American veterans. Results of a trial survey. Am J Phys Med (1983) vol. 62 (5) pp. 227-38

Status Quo

• PLP & current combat-related

amputations

– 77% after limb amputation

• 78% at least Weekly

• VAS 3 - 5.5 with medical tx

– 82% spoke with physician

• 68% received “treatment”

Ketz. The experience of phantom limb pain in patients with combat-related traumatic amputations. Archives of physical medicine and rehabilitation (2008) vol. 89 (6) pp. 1127-32

ASA Newsletter March 2007 Vol 71

“Conventional” PLP Tx’s

• opioids

• alpha-2 agonists

• non-steroidal anti-inflammatory

• N-methyl-D-aspartic acid (NMDA) antagonists

• binders

• Stim-stockings

• Periop Epidurals

• Minimal effect at one yearMinimal effect at one year

Phantom Limb Pain Mechanisms

Flor et al. Phantom limb pain: a case of maladaptive CNS plasticity?. Nat Rev Neurosci (2006) vol. 7 (11) pp. 873-881

Phantom Pain and Cortical Reorg

• Owl Monkey – microelectrode mapping– 2-8 months after surgical

amputation of a digit– Cortical area of intact

digits grew into areas previously representing the amputated digits

Merzenich et al. Somatosensory cortical map changes following digit amputation in adult monkeys. J Comp Neurol (1984) vol. 224 (4) pp. 591-605

PLP Neuroplastic Changes?

• Shift of cortical representation

– from neighboring

somatosensory/motor cortex

– To deafferented cortical areas

• Clinical manifestations

– Phantom limb sensations

– Phantom limb pain

Flor et al. Phantom limb pain: a case of maladaptive CNS plasticity?. Nat Rev Neurosci (2006) vol. 7 (11) pp. 873-881

Cortical Reorganization: fMRI

Amputee with PLP Amputee, no PL Control

Lotze et al. Phantom movements and pain. An fMRI study in upper limb amputees. Brain (2001) vol. 124 (Pt 11) pp. 2268-77 as referenced in Flor et al. Phantom limb pain:a case of maladaptive CNS plasticity?. Nat Rev Neurosci (2006) vol. 7 (11) pp. 873-881

“Virtual Reality Box”

“…mind-boggling. My arm is plugged in again; …I have often tried to move my phantom …without success, It no longer feels like it’s lifeless in a sling”

- Patient D.S.

Ramachandran and Rogers-Ramachandran. Synaesthesia in phantom limbs induced with mirrors.Proc Biol Sci (1996) vol. 263 (1369) pp. 377-86

Mirror Image TherapyLiterature

Ramachandran and Altschuler. The use of visual feedback, in particular mirror visual feedback, in restoring brain function. Brain (2009) vol. 132 (Pt 7) pp. 1693-710

Effective PLP Treatment

– Chan et al; NEJM 2007– 22 patients– Mirror Group

– 100% VAS– Avg 24 VAS change

– Covered Mirror– 17% VAS– 50% VAS

– Mental Imagery– 33% VAS– 67% VAS

• Changes in PLP as Measured on a 100-mm Visual-Analog Scale

Chan et al. Mirror therapy for phantom limb pain. N Engl J Med (2007) vol. 357 (21) pp. 2206-7

Limits of Current Studies

Few Randomized Controlled Studies– Small sample size– Limited Follow-up– No functional outcomes– No correlation with cortical reorganization– Not focused on prophylactic treatment

Methods

• The case series included four active duty male patients with blast injuries– multiple limb salvage surgeries– failed multimodal pain therapy– persistent severe pain– limited functional status– high risk for development of PLP– elective amputations planned

Methods

• Pre-operative Plan– daily 30-minute mirror therapy

for two weeks– 5-6 sessions supervised by a

physical therapist– followed by independent

sessions– observing unaffected leg

reflected in a mirror– mirror positioned midline– blocked view of the affected

legPhoto courtesy of David H. Peterzell, PhD

Pre-operative Results

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Case 1 Case 2 Case 3 Case 4

PLP - VASPT ComplianceUnassisted Ambulation

Future Research

- multi-centered study to include pre- and post- functional magnetic resonance imaging (fMRI)

Qazi et al; Resolving crossings in the corticospinal tract by two-tensor streamline tractogaphy: Method and clinical assessment using fMRI. NeuroImage 47 (2009) T98-T106.

Structural/Imaging Outcomes

• Produce fMRI PLP image library• Predict high risk patients• Predict treatment response

– Spinal Cord Stimulation– Deep Brain Stimulation– Cortical Stimulation

Outcomes

• Pain– VAS– Brief Pain Inventory

• Function– Timed Up and Go Test – Six minute walk Test

• Quality of Life– Patient Global

Impression of Change Scale

– Beck Depression Inventory

Mirror Therapy Summary

• Economical

• Non-invasive

• Low risk

• Efficacious Treatment

• Easily taught

• Perhaps Prophylactic

• Worldwide Applicability

Pain Medicine & Force Readiness

Low Back Pain & Readiness

• Low Back Pain– > 50% of OIF evacuated for

pain management

• Surgical Fusion– Limited demonstrated efficacy – Low return to full duty rates

• 37% Return to Full Duty– NMCSD Pre-published Data

– $11,000 cost

Cohen et al. Presentation, diagnoses, mechanisms of injury, and treatment of soldiers injured in Operation Iraqi Freedom: an epidemiological study conducted at two military pain management centers. Anesth Analg (2005) vol. 101 (4) pp. 1098-103, table of contents

Intradiscal BiacuplastyNon-surgical option for discogenic low back pain

• Technique – Utilizes radiofrequency generated lesions

to ablate nociceptive fibers within pain generating intravertebral discs

– Performed percutaneously under fluoroscopic guidance

– Out patient procedure

– Rapid recovery

– $2000

Intradiscal BiacuplastyNon-surgical option for discogenic low back pain

• Preliminary results Kapural et al. 2008, Cleveland Clinic

15 patients with discogenic pain

Oswestry, SF-36, VAS, opioid use

6 months:VAS - decreased 57%ODI - improved 28%SF-36 - improved 42%P<0.05

12 months:Unchanged from 6 months

No procedure related complications noted

Comparative Outcomes:Intradiscal Biacuplasty vs. Lumbar Fusion

• Proposed multicenter randomized trial– 60 subjects determined eligible for

Lumbar fusion will be randomized to IDB or fusion

– Oswestry disability index, VAS, SF-36 - pain and function, opioid use, Duty Status - determined at 3, 6 and 12 months

– Cross over to surgical limb at six months allowed

Does a cricothyroidotomy simulator enhance procedural proficiency in deployed medical personnel in Afghanistan?

The CricSim simulator affords the trainee a 3D stereoscopic view of the patient’s cricothyroid anatomy coupled with a bimanual haptic interface device attached to a desktop PC computer to provide the realistic feel encountered during cricothyroidotomy (1).

The CricSim simulator was previously used in Iraq to enhance the training combat medics received in cricothyroidotomy– a low frequency but high-risk lifesaving procedure. The simulator assessed comfort level with the procedure in 65 medics, showing high realism but moderate ease of use (2).

A follow-on study proposed at the level 3 treatment facility in Kandahar, Afghanistan using a refined CricSim simulator will seek to define proficiency as measured by time to perform a cricothyroidotomy and competence in completion of a standardized checklist, while evaluating its deployability and ease of operation in the theater of operations.

LCDR C. Cornelissena, M. Bowyerb, A. Liub, J. Lopreiatob

aMedical and Surgical Simulation Center, NMCSDbNational Capital Area Simulation Center, USUHS

(1) Liu A, Bhasin Y, Bowyer M. Stud Health Tech Inform. 2005, 111:308-313.

(2) Bowyer, M, Manahl M, Acosta E, Stutzmen J, Liu A. Stud Health Tech Inform. 2008, 132:37-41.

NMCSD Pain MedicineRelief, Restoration & Research

"The great thing in the world is not so much where we stand, as in what

direction we are moving."  

- Oliver Wendell Holmes

Cortical Effects of SCS

• First Implant 1966• Mechanism Unknown• Possible Induced

Cortical Neuroplasticity• MEG and SCS Trials

Magnetoencephalography (MEG)

Los Alamos National Laboratory Image