Transcript Post-Implant Clinical Care

Neurological Complications
following SCI
William McKinley MD
Director, SCI Rehabilitation Medicine
Associate Professor PM&R
VCU / MCV
Overview of Spinal Cord
Function / Injury
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Movement (Weakness)
Sensation (Sensory loss, Pain)
Muscle tone (Spasticity)
Bladder/bowel (Neurogenic B/B)
Sexuality (Sexual dysfunction)
Neurological Complications
Following SCI
• Syringomyelia
• Pain
• Spasticity
Syringomyelia
• Syrinx = fluid filled cavity (cyst) within the
spinal cord
• Syringomyelia = neurological symptoms
due to syrinx
– incidence - 3-10%
– etiology - trauma, tumor, congenital
• area of tissue damage / inflammation
• can expand, elongate, cause pressure
Syringomyelia: symptoms
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Pain (radicular)
Sensory loss
weakness
Spasticity
Hyperhydrosis
Bladder / bowel
Syringomyelia Diagnosis /
Treatment
• Dx:
– clinical findings / suspicion, physical exam
– MRI (CT/myelogram, U/S)
• Rx
– surgical shunt / drainage to “low” pressure
points
• syrigopleural, syringoperitoneal)
– pain management
SCI PAIN
• Challenging issue
– Physiologically & psychologically
• Incidence 15 - 85 %
• Etiology
– Spinal cord pain
– Radicular
– Muscuoskelletal
Factors associated with SCI Pain
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Level of Injury (LOI)
Complete vs Incomplete
Time since injury
Type of injury (GSW, trauma)
Psychological factors
Classification of SCI PAIN
• Central Pain
– Central Pain - below LOI, symmetrical
(burning, tingling)
• Radicular Pain
– At the LOI, asymmetrical (aching, stabbing)
• Musculoskelletal Pain
– localized MS structures (aching, tender)
Mechanism of Neurogenic SCI
Pain
• largely unknown
• Irritation / abnormal firing of damaged
nerve axons or roots
• Loss of descending inhibition
management of SCI Pain
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Pharmacological - neuropathic pain meds
Surgery
Adjunctive treatments
Psychological Rx
Neuropathic meds
• Anticonvulsants (nerve membrane
stabilization)
– Neurontin, Tegretol, Dilantin
• Antidepressants (increase Seritonin levels)
– Elavil, Trazadone
• Others : Mexiletine
• Epidural agents
– Morphine, Clonidine, baclofen
Non-pharmacologic Rx
• Spinal cord stimulation
– ? effectiveness
• Surface TENS
– best with radicular pain incomplete injuries
• Surgery
– Dorsal Root Entry Zone (DREZ)
Spasticity
• Definition: “Abnormal, velocity-dependent
increase in resistance to passive movement
of peripheral joints due to increased muscle
activity”
Spasticity: Etiology (Diagnosis)
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Spinal Cord Injury
Traumatic Brain Injury
Stroke
Multiple Sclerosis
Cerebral Palsy
Pathophysiology
• Intrinsic hyperexcitability of alpha motor
neurons within the spinal cord secondary to
damage to descending pathways
– cortico, vestibulo, reticulospinal
• CNS modification
– neuronal sprouting
– denervation hypersensitivity
Symptoms of Spasticity
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NEGATIVE SX’s
Weakness
Function
Sleep
Pain
Skin, hygiene
Social, Sexuality
contractures
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USEFUL SX’s
Stability
Function
Circulation
Muscle “bulk”
Spasticity: Treatment Decisions
• Is Spasticity:
– Preventing function?, Painful?
– A result of underlying treatable stimulus
– A set-up for further complications?
• What Rx has been tried?
• Limitations and SE’s of Rx…
• Therapeutic goals
Goals of Therapy
• Ease function (ambulation, ADL)
• Decrease Pain, contracture
• Facilitate ROM, hygiene
Spasticity Scales
• Ashworth Scale
• 1= no increased tone
• 2= slight “catch” in
ROM
• 3= moderate tone, easy
ROM
• 4= marked tone,
difficult ROM
• 5= Rigid in flexion or
extension
• Spasm Frequency
Scale
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0= none
1= mild
2= infrequent
3=> 1 per hour
4= > 10 per hour
Rehab Evaluation (con’t)
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Gait patterns
Transfer abilities
Resting positioning
Balance
Endurance
Management Options
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Physical interventions
systemic medications
chemical denervation
Intrathecal agents
orthopedic interventions
neurosurgical interventions
Rehabilitation Interventions
• Positioning (bed, wheelchair)
• Modalities
– heat (relaxation)
– cold (inhibition)
• Therapeutic Exercise
– inhibitory to spastic muscles
– facilatory to opposing muscles
• Orthotics
Non-Conservative Treatment
Options
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Oral Medications
Injections (Phenol , Botox)
ITB (Intra-Thecal Baclofen)
Surgical (nerve, root, SC)
Spinal Cord Stimulator
Oral Antispasticity Medications
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Baclofen
Dantrium
Diazepam
Clonidine
Tizanidine
• (limitations: non-selective, side effects)
Baclofen (Lioresal)
• GABA-B analogue; binds to receptors
• inhibits release of excitatory
neurotransmitters (spasticity control)
– Ca++ (pre-synaptic inhibition)
– K+ (post-synaptic inhibition)
• may also decrease release of substance P
(pain control)
Dantrium
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Inhibits Ca++ release at muscle level
Preferred : TBI, CVA, CP
SE’s - weakness, GI
Hepatotoxicity (<1%)
Diazepam
• GABA “potentiation”
• Usage : SCI, MS
• SE’s - CNS depression, dependence,
Clonidine
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Alpha-2 receptor blockage
Usage : SCI
Max dose - .4mg/d (oral & patch)
SE’s - OH, syncope, drowsiness
Tizanidine (Zanaflex)
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1996 - Approved for SCI, MS, CVA
Alpha-2 agonist (pre-synaptic inhibition)
1/10 potency of Clonidine In lowering BP
Dose: T1/2: 2-5hr, begin 4 mg qhs (max 36
mg)
• SE’s - Sedation, nausea, LFT’s
Chemical Neurolysis
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Phenol 5-7%- Motor Point/Nerve block
Non-selective destruction of axons/myelin
Inds: Local (not general) spasticity
Duration: 3-6 months
SE’s - dysesthetic pain
Botulinum Toxin
• 1989 FDA approved for strabismus &
blepherospasm
• Botox-A inhibits Ach Release at NMJ
• Dose: 300-400u total (50-200/muscle)
• Onset: 2-4 hours, Peak : 2-4 weeks
• Duration: 3-6 months
• ? Immunoresistance w/repeated inj’s
Spasticity: Surgical Management
• Rhizotomy (posterior)
• Cordotomy
• Tendon Release
– (limitations: invasive, bowel/bladder changes,
irreversible, effectiveness varies)
Intrathecal Baclofen and
Spasticity
• Intrathecal delivery of baclofen via an
inplantable pump is a safe and effective
therapy for the management of spasticity !
Intrathecal Baclofen
• Indicated for patients unresponsive to oral
meds or with SE’s
• Delivered directly to intrathecal space
affording much higher drug concentration
• Implantable system allows non-invasive
monitoring & adjustments
ITB: Successful Outcomes
• Study results since 1984 demonstrate
reduction of Ashworth spasticity scores and
spasm scales
• Other results include improvements in:
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pain
bladder function
chronic drug side effects
quality of life for patient & caregiver
ITB
• 1992 - FDA Approved ITB for spinal
Spasticity
• 1996 - FDA Approved for Cerebral
Etiologies (BI and CP)
ITB: Pharmacokinetics
• Baclofen: GABA-b agonist; inhibits
neuronal firing
• ITB (Lioresal)
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preservative-free; stable for 90 days
half-life 1.5 hours
typical dose: 1/100 of oral dose
average daily dose: 300-800ug
lumbar/cervical ratio 4:1
Decision to Treat w/ ITB
• Have oral antispasticity meds truly failed?
• Are their SE’s too great?
• Can a single definitive surgical procedure
accomplish similar goals?
• Is precise control necessary for functional
gains?
• Does gain in function / comfort justify
invasive procedure & maintenance?
Other Considerations ITB
• Test dosing / trial dose via intrathecal
lumbar puncture
• Pump re-programming via radio-telemetry
and computer
• Maintenance follow-up: Q 4-12 weeks
THE END