Spasticity

CHAPTER 154

Spasticity Joel E. Frontera, MD Monica Verduzco-Gutierrez, MD

Synonyms Increased muscle tone Spastic dystonia

ICD-10 Codes M62.838 R25.9 R29.3 G25.3

Muscle spasm Abnormal involuntary movements Abnormal posture Myoclonus

Definition Spasticity is commonly defined as a velocity-dependent increase in muscle tone with exaggerated tendon jerks resulting from hyperexcitability of the stretch reflex. This means that the faster the passive movement of the limb through its range, the greater the increase in muscle tone. Thus spasticity can be considered a component of an upper motor neuron (UMN) syndrome, which is also associated with hyperreflexia, clonus, muscle cocontraction, and muscle weakness. Spasticity can be caused by a variety of conditions. It is often noted to be a major problem in spinal cord injury, multiple sclerosis, and traumatic brain injury. It is estimated to affect between 40% and 80% of patients with a spinal cord injury or multiple sclerosis, and the prevalence can be as high as 80% in patients with traumatic brain injury. Spasticity can also be present in other conditions like amyotrophic lateral sclerosis, brain and spinal cord tumors, and cerebral palsy. 

Symptoms Patients with spasticity may complain of increased tightness, worsening spasms, and pain. However, the main complaint can be worsening of functional activities. The ability to move affected limbs, actively or passively, is reduced. Spasticity significantly interferes with routine tasks and even hygiene (e.g., increased elbow flexor spasticity in a stroke survivor while walking; adductor spasticity in a paraplegic individual during bladder management) while at the same time causing pain and muscle cocontraction. These symptoms may reflect 890

an increase in spasticity due to a secondary condition such as an infectious process, skin pressure injuries, and cord tethering. Therefore when a patient comes to clinic complaining of worsening spasticity, a thorough history and physical examination should be performed to identify the cause. 

Physical Examination Spasticity occurs in the presence of other signs and symptoms of UMN damage. The physical examination may show hyperreflexia, Babinski responses, and clonus. Other signs include muscle weakness, fatigue, reduced motor control, and loss of coordination. Increased muscle tone in the absence of these findings should lead to consideration of alternative causes such as dystonia, Parkinson disease, or pain-associated muscle spasm. Strength testing may not be valid, as the spasticity may affect joint range of motion due to contractures as cocontraction of antagonist muscles may interfere with the test. Muscle contracture as well as other soft tissue changes can be a part of this UMN syndrome, and it may be difficult in some cases to determine how much contracture is present with the severe spasticity. A thorough physical examination can also show sensory disturbances (proprioception and spatial orientation), dysphagia, dysarthria, and skin problems. The skin should be inspected carefully, because abnormal positioning due to spasticity may directly cause skin injury (e.g., maceration of the palm due to a clenched fist) or contribute to the formation of pressure ulcers. It is important to differentiate spasticity from rigidity, commonly seen in conditions like Parkinson disease. One must look at some physical examination findings that occur with spasticity, such as the clasp-knife phenomenon. There is also variability in evaluating antagonistic muscles. In spasticity, for example, some muscle groups are more affected than their antagonists. Rigidity is not velocity-dependent; it is constant throughout the whole range of motion. 

Functional Limitations Spasticity can cause significant functional limitations. In a spinal cord injury patient, for example, spasticity can have a serious impact on positioning. It can affect wheelchair positioning as well as transfers. Hygiene and bladder management may be affected by significant increases in hip adductor tone. It will affect dexterity and fine motor coordination in the upper extremities. The use of bracing or other modalities to assist with ambulation may be limited if the spasticity

CHAPTER 154 Spasticity

Table 154.1  Modified Ashworth Scale 0

No increase in muscle tone

1

Slight increase in muscle tone, manifested by a catch and release or by minimal resistance at the end range of motion when the part is moved in flexion or extension/ abduction or adduction

1+

Slight increase in muscle tone, manifested by a catch, followed by minimal resistance throughout the remainder (less than half) of the range of motion

2

More marked increase in muscle tone through most of the range of motion, but the affected part is easily moved

3

Considerable increase in muscle tone, passive movement is difficult

4

Affected part is rigid in flexion or extension (abduction or adduction)

From McCormick ZL, Chu SK, Binler D, et al. Intrathecal versus oral baclofen: a matched cohort study of spasticity, pain, sleep, fatigue, and quality of life. PM R. 2016;8(6):553–562.

Table 154.2  Penn Spasm Frequency Scale How often are muscle spasms occurring? 0

No spasms

1

Spasms induced only by stimulation

2

Spasms occurring less than once per hour

3

Spasms occurring between 1 and 10 times per hour

4

Spasms occurring more than 10 times per hour

From Conroy B, Zorowitz R, Horn SD, et al. An exploration of central nervous system medication use and outcomes in stroke rehabilitation. Arch Phys Med Rehabil. 2005;86(12 suppl 2):S73–S81.

is significant. Studies have found that a significant number of patients with both spinal cord injury and traumatic brain injury have noted that spasticity affects quality of life. It is interesting that in some cases, spasticity may serve as a partial substitute for voluntary muscle contraction. A common example of substitution for voluntary muscle function is the hip and knee extensor spasticity seen after stroke, which may allow successful weight bearing through the hemiparetic leg and contribute to the restoration of walking ability. 

Diagnostic Studies Spasticity is a clinical diagnosis; there is no specific laboratory test for confirmation. Clinical measurement scales to quantify the severity of spasticity may be useful to monitor the efficacy of treatment. The most commonly used scales are the Ashworth Scale (and a modified version of this scale),1 which measures resistance of the muscle to passive stretch, and the Penn Spasm Frequency Scale, which characterizes the frequency of muscle spasms (Tables 154.1 and 154.2).2  Differential Diagnosis Dystonia Rigidity (e.g., Parkinson disease) Paratonia Pain-associated muscle spasm Contracture

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Treatment Initial The treatment of spasticity depends on the clinical and functional needs of the patient. As noted before, spasticity can be used to the patient’s advantage, such as ambulation in the presence of spastic hemiparesis. Treatment should be started when spasticity becomes an obstacle to functional goals, represents a safety risk (spasms while transferring, which could lead to a fall), impairs hygiene, or damages skin integrity. A change in previously well-controlled spasticity should always lead to the consideration of possible irritants or nociceptive stimuli that might be “triggering” the spasticity. Examples are urinary tract infections, skin pressure injuries, occult fractures, and an ingrown toenail in an insensate limb (e.g., in a paraplegic person). Several oral medications (Table 154.3) have been used to treat spasticity, depending on the underlying disease, with mixed results. Spasticity caused by injury to the spinal cord tends to respond better to baclofen and tizanidine than spasticity caused by a traumatic brain injury or stroke. However, centrally acting medications such as baclofen, tizanidine,4 and the benzodiazepines have significant side effects that may impair cognition and overall recovery after an acquired brain injury.3 Another commonly used drug is dantrolene,5 which works directly at the muscle level, preventing calcium flux at the sarcoplasmic reticulum and thereby reducing muscle force. 

Rehabilitation A program of therapeutic exercise, stretching, and passive range-of-motion exercises initiated by trained physical and occupational therapists is imperative for the management of spasticity regardless of cause. The goals of therapeutic exercise are to maintain range of motion, prevent contractures, reduce muscle overactivity, and disrupt maladaptive spasticity patterns. Active exercise can also increase muscle strength.6 Stretching and passive range-of-motion exercises help to prevent contracture formation and temporarily reduce muscle tone, especially in patients who are not capable of active movement. Therapists can instruct the patient and caregivers in appropriate stretching techniques. Standing has also been shown to be helpful in tone management. Physical modalities including therapeutic ultrasound have been used to facilitate stretching, though in one trial it had no effect in minimizing the spasticity of the gastrocnemius muscle when compared with passive stretching exercises.7 Another study showed that neuromuscular electrical stimulation with stretching of the wrist extensor muscles was more effective in reducing spasticity than stretching alone.8 External cooling of a spastic limb may provide a temporary reduction in spasticity, but this modality is generally impractical as a long-term therapy. The use of orthotic devices is another important treatment in a comprehensive spasticity rehabilitation program. This can include prefabricated splints, low-temperature thermoplastic custom orthotics, and plaster or fiberglass casts. Serial casting has been shown to be effective both on its own and after botulinum toxin treatment in improving both passive range of motion and scores on the Modified Ashworth Scale.9 

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Table 154.3  Commonly Used Oral Antispasticity Medications Medication

Mechanism of Action

Starting Dose

Common Side Effects

Relative ­Contraindications

Baclofen

GABA-B agonist Increases pre synaptic and post-synaptic inhibition

5–10 mg tid (max dose 80 mg/day)

Sedation, rare hepatotoxicity, withdrawal symptoms

Cognitive impairment, seizures

Diazepam (Benzodiazepines)

GABA-A agonist

2 mg tid

Sedation, respiratory, ataxia

History of benzodiazepine or other substance abuse

Tizanidine

Alpha-2 agonist; suppresses poly-synaptic reflexes

2 mg tid (max dose 32 mg/day)

Sedation, hypotension, hepatotoxicity

Cognitive impairment

Dantrolene

Prevents calcium influx at the sarcoplasmic reticulum in the muscle

25 mg/day

Weakness, hepatotoxicity, occasional sedation

Liver disease

Procedures

Technology

Local injections are an effective means of obtaining substantial reductions in spasticity in specific muscles while minimizing the risks of systemic or sedating side effects. Prior to botulinum toxin, two compounds were frequently used for local muscle relaxation: local anesthetics (lidocaine, etidocaine, and bupivacaine) and alcohols (ethyl alcohol and phenol). Local anesthetic injections have a fully reversible action and are of short duration; therefore they can be useful in assessing the efficacy and benefits of more permanent injections. Chemical neurolysis with phenol in concentrations of 5% to 7% and alcohol in concentrations of 45% to 100% have the advantage of lower cost, a rapid onset of action, and potency; however, because of the associated potential side effects—such as dysesthesias and muscle fibrosis—they require more skill and time to perform.10 Chemodenervation with botulinum toxin has become a mainstay of practice in the treatment of spasticity for graded relief in selected muscles. Intramuscular injection of botulinum toxin provides local relief of spasticity for 2 to 6 months. There are currently four toxins available: onabotulinumtoxinA, rimabotulinumtoxinB, abobotulinumtoxinA, and incobotulinumtoxinA. Ample scientific literature supports the use of all four agents, and the US Food and Drug Administration (FDA) has approved them for the treatment of cervical dystonia. More recent evidence also supports all type A toxins to be used for the indication of spasticity.11–14 Although toxins have been used “off-label” for spasticity for over 20 years, there is now FDA approval for type A toxins to be used in spasticity. The American Academy of Neurology published an evidence-based practice guideline update summary on botulinum neurotoxin in 2016. The guideline includes level A evidence supporting the use of botulinum toxin (abobotulinumtoxinA, incobotulinumtoxinA, and onabotulinumtoxinA) as a treatment to decrease spasticity of the upper limbs.15 It has been noted that adjunctive treatments such as physical and occupational therapy will improve outcomes.16 It is important to remember that the dosing and administration of botulinum toxins are not standardized and must be managed with great care, as the four toxins are not clinically equivalent. Some differences between the four botulinum toxins are shown in Table 154.4. 

There are new investigations into utilizing robotics or spinal cord stimulators for spasticity management. Robotic locomotor training via a treadmill—a motorized exoskeleton that attaches to the patient’s legs—is an intervention used to promote gait recovery and improve function. At this time, the effects of robotic-assisted step training on spasticity have been inadequately studied and remain controversial. The study results from spinal cord stimulators are also controversial. 

Surgery Several surgical interventions may be used to treat spasticity. An important intervention is placement of an intrathecal baclofen pump into the abdominal wall. In this system, there is an infusion of a prescribed dosage of baclofen that is administered to the intrathecal space using a catheter system. This intervention has been found to reduce severe spasticity of cerebral and spinal origin in a variety of patients including those with cerebral palsy, spinal cord injury, brain injury, multiple sclerosis, and stroke. Evidence suggests that intrathecal baclofen can improve not only spasticity but also function and quality of life17; in ambulatory patients, it has been shown to improve gait.18,19 Other surgical techniques include stereotactic ablation of the dentate nucleus, spinal cord stimulation, and cerebellar stimulation, which have been shown to have variable to uncertain results. Spinal cord surgeries such as selective posterior rhizotomy and myelotomy have been used in specially selected patients. Orthopedic consultation can be done for further correction of limb deformities when conservative measures have been ineffective. Surgical procedures—including tendon release or lengthening, tenotomy, and joint fusion—can lead to improvement in functional outcome, pain, and subjective satisfaction.20,21 

Potential Disease Complications Permanent loss of range of motion and contracture can result from inadequately controlled spasticity or insufficient stretching and splinting. Lost range of motion can also lead to difficulty with dressing, hygiene, and grooming

CHAPTER 154 Spasticity

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Table 154.4  Characteristics of Different Botulinum Toxins OnabotulinumtoxinAa

AbobotulinumtoxinAb

IncobotulinumtoxinAc

RimabotulinumtoxinBd

Serotype

A

A

A

B

Packaging, units/vial

100 or 200

300 or 500

50 or 100

2500, 5000, or 10,000

Preparation

Vacuum-dried

Lyophilized

Lyophilized

Solution (5000 U/mL)

Storage for packaged product

Refrigerator

Refrigerator

Room temperature, refrigerator or freezer

Refrigerator

Storage post reconstitution

2°C–8°C for 24 h

2°C–8°C for 4 h

2°C–8°C for 24 h

2°C–8°C for 4 h

aAllergan.

Botox medication guide. www.allergan.com. Dysport medication guide. www.dysport.com. cMerz. Xeomin medication guide. www.xeomin.com. dSolstice Neurosciences. Myobloc medication guide. www.myobloc.com. bIpsen.

activities. Skin issues can result, including the accumulation of moisture, skin irritation, bacterial overgrowth, infection, and skin breakdown. Bone and joint issues can occur, such as adhesive capsulitis, complex regional pain syndrome, and subluxation of joints. 

to the pump, catheter, or human error. Interruption or underdosing of drug delivery can lead to a life-threatening withdrawal syndrome. Catheter failures can result in need for surgical intervention.

Potential Treatment Complications

1. Bohannon RW, Smith MB. Interrater reliability of a modified Ashworth scale of muscle spasticity. Phys Ther. 1987;67:206–207. 2. McCormick ZL, Chu SK, Binler D, et al. Intrathecal versus oral baclofen: a matched cohort study of spasticity, pain, sleep, fatigue, and quality of life. PM R. 2016;8(6):553–562. 3. Conroy B, Zorowitz R, Horn SD, Ryser DK, Teraoka J, Smout RJ. An exploration of central nervous system medication use and outcomes in stroke rehabilitation. Arch Phys Med Rehabil. 2005;86(12 suppl 2): S73–S81. 4. Chu VW, Hornby TG, Schmit BD. Effect of antispastic drugs on motor reflexes and voluntary muscle contraction in incomplete spinal cord injury. Arch Phys Med Rehabil. 2014;95(4):622–632. 5. Kita M, Goodkin DE. Drugs used to treat spasticity. Drugs. 2000;59: 487–495. 6. Stevenson VL. Rehabilitation in practice: spasticity management. Clin Rehabil. 2010;24:293–304. 7. Sahin N, Ugurlu H, Karahan AY. Efficacy of therapeutic ultrasound in the treatment of spasticity: a randomized controlled study. NeuroRehabilitation. 2011;29(1):61–66. 8. Sahin N, Ugurlu H, Albayrak I. The efficacy of electrical stimulation in reducing the post-stroke spasticity: a randomized controlled study. Disabil Rehabil. 2012;34(2):151–156. 9. Logan LR. Rehabilitation techniques to maximize spasticity management. Top Stroke Rehabil. 2011;18(3):203–211. 10. Elovic E, Esquenazi A, Alter K, Lin JL, Alfaro A, Kaelin D. Chemodenervation and nerve blocks in the diagnosis and management of spasticity and overactivity. PM R. 2009;1:842–851. 11. Brashear A, Gordon MF, Elovic E, et al. Botox Post-Stroke Spasticity Study Group. Intramuscular injection of botulinum toxin for the treatment of wrist and finger spasticity after a stroke. N Engl J Med. 2002;347:395–400. 12. Elovic EP, Brashear A, Kaelin D, et al. Repeated treatments with botulinum toxin type A produce sustained decreases in the limitations associated with focal upper-limb poststroke spasticity for caregivers and patients. Arch Phys Med Rehabil. 2008;89:799–806. 13. Gracies JM, Brashear A, Jech R, et al. Safety and efficacy of abobotulinumtoxinA for hemiparesis in adults with upper limb spasticity after stroke or traumatic brain injury: a double-blind randomized controlled trial. Lancet Neurol. 2015;14(10):992–1001. 14. Elovic EP, Munin MC, Kanovsky P, et al. Randomized, placebo-controlled trial of incobotulinumtoxinA for upper-limb post-stroke spasticity. Muscle Nerve. 2016;53(3):415–421. 15. Simpson DM, Hallett M, Ashman EJ, et al. Practice guideline update summary: Botulinum neurotoxin for the treatment of blepharospasm, cervical dystonia, adult spasticity, and headache: report of the Guideline Development Subcommittee of the American Academy of Neurology. Neurology. 2016;86:1818–1826. 16. Esquenazi A, Mayer N, Lee S, et al. PROS study group. Patient registry of outcomes in spasticity care. Am J Phys Med Rehabil. 2012;91:729–746.

All of the centrally acting medications can cause significant sedation, which limits the dosage that can be tolerated. In individuals with preexisting cognitive impairments (e.g., stroke, traumatic brain injury), the sedative side effects can hinder rehabilitation goals and the maximally tolerated dosage may be insufficient to control the symptoms of spasticity. Alternative treatments or use of the agents only prior to bedtime can be considered. Abrupt discontinuation of oral antispasticity medications is inadvisable. Seizures have been described after abrupt discontinuation of baclofen, and rebound spasticity is a concern with all of these medications. In individuals with marginal motor function who may be relying in part on spasticity as a substitute for voluntary motor control, excessive reduction in spasticity may lead to reduced functional ability (e.g., loss of the ability to stand in a patient with paraparesis). Oral medication or intrathecal baclofen doses can generally be titrated to avoid this side effect; however, injected treatments (botulinum toxin, phenol) are more problematic if overtreatment occurs. Phenol carries some risk for painful dysesthesia, muscle fibrosis, scarring, and edema postinjection. Botulinum toxin is generally well tolerated in therapeutic doses but does carry an FDA-mandated black box warning of a rare but potentially life-threatening complication when the effects of the toxin spread far beyond the injection site, causing systemic weakness, vision changes, dysarthria, dysphonia, dysphagia, and respiratory insufficiency. This can be avoided by the careful selection of muscles, proper method of injection guidance (e.g., electromyography, ultrasound, or motor-point electrical stimulation), appropriate dilution of toxin, and restricting dosage to the minimum needed to obtain a therapeutic effect. Antibodies to botulinum toxin can develop after repeated injection, which can render treatment ineffective. Intrathecal baclofen pump treatment can result in post– dural puncture headache, iatrogenic meningitis or infection of the external surface of the pump. Complications can also involve the medication (e.g., known adverse effects of baclofen are drowsiness and weakness), but they are more frequently the result of malfunction of the ITB system due

References

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17. Ivanhoe CB, Francisco GE, McGuire JR, Subramanian T, Grissom SP. Intrathecal baclofen management of poststroke spastic hypertonia: implications for function and quality of life. Arch Phys Med Rehabil. 2006;87(11):1509–1515. 18. Sadiq SA, Wang GC. Long-term intrathecal baclofen therapy in ambulatory stroke patients with spasticity. J Neurol. 2006;253:563–569. 19. Francisco GE, Boake C. Improvement in walking speed in poststroke spastic hemiplegia after intrathecal baclofen therapy: a preliminary study. Arch Phys Med Rehabil. 2003;84:1194–1199.

20. Namdari S, Park MJ, Baldwin K, Hosalkar HS, Keenan MA. Effect of age, sex, and timing on correction of spastic equinovarus following cerebrovascular accident. Foot Ankle Int. 2009;30(10):923–927. 21. Gong HS, Chung CY, Park MS, Shin HI, Chung MS, Baek GH. Functional outcomes after upper extremity surgery for cerebral palsy: comparison of high and low manual ability classification system levels. J Hand Surg Am. 2010;35(2):277–283.e1–e3.