Neurological Complications following SCI William McKinley MD Director, SCI Rehabilitation Medicine Associate Professor PM

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Neurological Complications following SCIWilliam
McKinley MDDirector, SCI Rehabilitation Medicine
Associate Professor PMRVCU / MCV
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Overview of Spinal Cord Function / Injury

• Movement (Weakness)
• Sensation (Sensory loss, Pain)
• Muscle tone (Spasticity)
• Bladder/bowel (Neurogenic B/B)
• Sexuality (Sexual dysfunction)

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Neurological Complications Following SCI

• Syringomyelia
• Pain
• Spasticity

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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

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Syringomyelia symptoms

• Pain (radicular)
• Sensory loss
• weakness
• Spasticity
• Hyperhydrosis
• Bladder / bowel

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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

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SCI PAIN

• Challenging issue
• Physiologically psychologically
• Incidence 15 - 85
• Etiology
• Spinal cord pain
• Radicular
• Muscuoskelletal

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Factors associated with SCI Pain

• Level of Injury (LOI)
• Complete vs Incomplete
• Time since injury
• Type of injury (GSW, trauma)
• Psychological factors

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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)

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Mechanism of Neurogenic SCI Pain

• largely unknown
• Irritation / abnormal firing of damaged nerve
  axons or roots
• Loss of descending inhibition

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management of SCI Pain

• Pharmacological - neuropathic pain meds
• Surgery
• Adjunctive treatments
• Psychological Rx

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Neuropathic meds

• Anticonvulsants (nerve membrane stabilization)
• Neurontin, Tegretol, Dilantin
• Antidepressants (increase Seritonin levels)
• Elavil, Trazadone
• Others Mexiletine
• Epidural agents
• Morphine, Clonidine, baclofen

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Non-pharmacologic Rx

• Spinal cord stimulation
• ? effectiveness
• Surface TENS
• best with radicular pain incomplete injuries
• Surgery
• Dorsal Root Entry Zone (DREZ)

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Spasticity

• Definition Abnormal, velocity-dependent
  increase in resistance to passive movement of
  peripheral joints due to increased muscle
  activity

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Spasticity Etiology (Diagnosis)

• Spinal Cord Injury
• Traumatic Brain Injury
• Stroke
• Multiple Sclerosis
• Cerebral Palsy

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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

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Symptoms of Spasticity

• NEGATIVE SXs
• Weakness
• Function
• Sleep
• Pain
• Skin, hygiene
• Social, Sexuality
• contractures

• USEFUL SXs
• Stability
• Function
• Circulation
• Muscle bulk

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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 SEs of Rx
• Therapeutic goals

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Goals of Therapy

• Ease function (ambulation, ADL)
• Decrease Pain, contracture
• Facilitate ROM, hygiene

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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
• 0 none
• 1 mild
• 2 infrequent
• 3gt 1 per hour
• 4 gt 10 per hour

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Rehab Evaluation (cont)

• Gait patterns
• Transfer abilities
• Resting positioning
• Balance
• Endurance

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Management Options

• Physical interventions
• systemic medications
• chemical denervation
• Intrathecal agents
• orthopedic interventions
• neurosurgical interventions

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Rehabilitation Interventions

• Positioning (bed, wheelchair)
• Modalities
• heat (relaxation)
• cold (inhibition)
• Therapeutic Exercise
• inhibitory to spastic muscles
• facilatory to opposing muscles
• Orthotics

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Non-Conservative Treatment Options

• Oral Medications
• Injections (Phenol , Botox)
• ITB (Intra-Thecal Baclofen)
• Surgical (nerve, root, SC)
• Spinal Cord Stimulator

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Oral Antispasticity Medications

• Baclofen
• Dantrium
• Diazepam
• Clonidine
• Tizanidine
• (limitations non-selective, side effects)

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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)

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Dantrium

• Inhibits Ca release at muscle level
• Preferred TBI, CVA, CP
• SEs - weakness, GI
• Hepatotoxicity (lt1)

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Diazepam

• GABA potentiation
• Usage SCI, MS
• SEs - CNS depression, dependence,

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Clonidine

• Alpha-2 receptor blockage
• Usage SCI
• Max dose - .4mg/d (oral patch)
• SEs - OH, syncope, drowsiness

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Tizanidine (Zanaflex)

• 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)
• SEs - Sedation, nausea, LFTs

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Chemical Neurolysis

• Phenol 5-7- Motor Point/Nerve block
• Non-selective destruction of axons/myelin
• Inds Local (not general) spasticity
• Duration 3-6 months
• SEs - dysesthetic pain

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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 injs

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Spasticity Surgical Management

• Rhizotomy (posterior)
• Cordotomy
• Tendon Release
• (limitations invasive, bowel/bladder changes,
  irreversible, effectiveness varies)

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Intrathecal Baclofen and Spasticity

• Intrathecal delivery of baclofen via an
  inplantable pump is a safe and effective therapy
  for the management of spasticity !

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Intrathecal Baclofen

• Indicated for patients unresponsive to oral meds
  or with SEs
• Delivered directly to intrathecal space affording
  much higher drug concentration
• Implantable system allows non-invasive monitoring
  adjustments

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ITB Successful Outcomes

• Study results since 1984 demonstrate reduction of
  Ashworth spasticity scores and spasm scales
• Other results include improvements in
• pain
• bladder function
• chronic drug side effects
• quality of life for patient caregiver

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ITB

• 1992 - FDA Approved ITB for spinal Spasticity
• 1996 - FDA Approved for Cerebral Etiologies (BI
  and CP)

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ITB Pharmacokinetics

• Baclofen GABA-b agonist inhibits neuronal
  firing
• ITB (Lioresal)
• 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 41

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Decision to Treat w/ ITB

• Have oral antispasticity meds truly failed?
• Are their SEs 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?

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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

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THE END