Neurological Complications following SCI William McKinley MD Director, SCI Rehabilitation Medicine Associate Professor PM&R VCU / MCV

Overview of Spinal Cord Function / Injury • 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 • 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 • 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 • 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) • 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 • NEGATIVE SX’s • Weakness • Function • Sleep • Pain • Skin, hygiene • Social, Sexuality • contractures • 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 • 0= none • 1= mild • 2= infrequent • 3=> 1 per hour • 4= > 10 per hour

Rehab Evaluation (con’t) • Gait patterns • Transfer abilities • Resting positioning • Balance • Endurance

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

Oral Antispasticity Medications • 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 • 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 • Alpha-2 receptor blockage • Usage : SCI • Max dose - .4mg/d (oral & patch) • SE’s - OH, syncope, drowsiness

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) • SE’s - Sedation, nausea, LFT’s

Chemical Neurolysis • 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: – 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) – 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

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