Transcript Post-Implant Clinical Care

Intrathecal Baclofen Pump &
other management strategies for
Spasticity
William O McKinley MD
Director, SCI Rehabilitation Medicine
Dept. PM&R
VCU / MCV
What is Spasticity ?
• 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
• “Modified” Ashworth
• 0= no increased tone
• 1= slight “catch” in
ROM
• 1+= minimal resistance
• 2= moderate tone, easy
ROM
• 3= marked tone,
difficult ROM
• 4= 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: Outcome Studies
• “Intrathecal baclofen for spasticity of spinal
origin: seven years of experience”…Penn*
(J. neurosurg 77:236-40, 1992)
– 66 patients with intractable spasticity
– followed for 30 months
– “It is suggested that long term control of spinal
spasticity by intrathecal baclofen can be
achieved in most patients”
ITB: Outcome Studies
• “Intrathecal baclofen for intractable
spasticity of Spinal of spinal origin: a longterm multicenter study”…..Coffe* (J.
Neurosurg 78; 226-32, 1993)
– 93 patients with intractable spasticity
– followed 19 months
– “Results indicate intrathecal baclofen can be
safe and effective for long term management in
SCI or MS”
Outcome Studies: Meta Analysis
• *Dijkers- Meta analysis of 37 studies
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77% positive response to bolus dose
91% of whom opted for implant
84% of whom had benefit w/o SE’s
Avg Dec’d Ashworth: 3.95-1.53 (P<.0001)
negligible effect of LOI
• * J.Spinal Cord Med:19(2), 138, 1996
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?
Exclusion Criteria
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Severely impaired renal function
Pregnancy / nursing mothers
Severe Aut. Dysreflexia
Hx of Hypersensitivity to baclofen
Hx of Noncompliance to regimens or
follow-up
Trial Dose
• Trial dose via intrathecal lumbar puncture
• Begin with 50 ug (if no response, 75-100
ug)
• Observe 2-8 hrs
• Positive response = decrease in spasticity
• also access functional abilities
ITB: Surgical Phase
• Subcutaneous abdominal placement
• Catheter tunneled to mid-lumbar region
below L3 and advanced 10 cm
• Intra-operative fluoroscopy confirms
catheter placement without twisting
• Total time: 1-2 hours
Post-Operative Phase
• Pump programming via radio-telemetry and
computer begins day one post-imp;ant
• ITB concentration: 500mcg/ml
• ITB rate: 2 X bolus response (less if patient
had prolonged (>12 hrs) response)
• Can increase 10-15% every 24 hrs
• maintenance follow-up: 1-4 weeks
Post-Implant Clinical Care
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Post-Operative Adjustments
Pump Dosing Adjustments
Taper Oral Meds
Pump Refills
Patient Education
ITB: Maintenance Phase
• scheduled follow-ups for pump
reassessment, refill and reprogramming
– percutaneous refill into “port” (template)
– dose adjustment: portable computer/telemetry
– calculate next refill date
• if sudden changes in spasticity occurs,
assess for potential infection, bowel/bladder
regimen, before increasing dosage
• consider “drug holiday”
Pump Adjustments
• Adjustment parameters include:
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drug name and concentration
reservoir status ( __ ml)
alarms (low battery; low reservoir)
infusion rate
infusion pattern (continuous, intermittent,
complex)
– may increase by up to 15% per adjustment
Infusion Modes
• Continuous: drug delivered at continuous
specified rate
• Continuous-complex: step-wise
increases/decreases at specified times
• Bolus-delay: drug delivered intermittently
at specific intervals
ITB Side Effects
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Drowsiness
Dizziness
Blurred Vision
Slurred Speech
Nausea
Orthostasis
Confusion
Potential Pump Complications
• Drug over-infusion - somnolence, coma
– no antidote
– Physostigmine 1-2mg IV (.02 mg/kg) over 5-10
min
– titrate ITB
• Pump / Catheter malfunctions (kinking,
disconnection, breaks)…often readily
correctable under local anesthesia
• Infections
Pump /System Complications &
Trouble-shooting
• r/o volume discrepancy
– check pump setting
– empty & compare fluid reservoir
• r/o catheter kink, occlusion, disconnection
– X-Ray catheter / CT intrathecal catheter
– dye/ contrast study to check patency
– bolus/infusion w/sereal scans over 12-24 hr
• r/o pump underinfusion
– X-Ray “roller” pre/post bolus
Pocket Complications
• seroma, hematoma, infection
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post-op swelling
inadequate fixation
infection
pocket too small
drug extravasation
Suspected CSF Leak
• headache, dizziness, N/V, spinal swelling /
redness
• RX:
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X-Ray / CT
culture of fluid
blood patch
surgical revision
Advantages of Programmable
System
• Consistent optimal dosage
• can be programmed to decrease or increase
spasticity at certain times during the day
• reduces adverse drug effects