The Management of Upper Limb Spasticity

“The Management of Upper Limb Spasticity” is the fifth article in a series to address Myoguide Injection Guidance applications of Botulinum neurotoxin. The following article presents a short review of the Upper limb Spasticity and the application of BoNT, with a focus on the benefit of using the Myoguide™ EMG/ESTIM BoNT injection guidance system. While we did cover some of this in the Hand Dystonia post, the following presents more detail, specifically aimed at the management of upper limb spasticity. The information within, is simply informative and not considered to be instructive, in any way. Please have a look at the article and the appropriate reference materials for more details.

Upper limb spasticity is a condition where the muscles of the arms and hands become tense and overactive, resulting in limited movement and an inability to perform basic daily tasks. This can cause unusual and uncontrollable muscle movements (spasms) in the arm.

People with upper-limb spasticity may also have trouble coordinating the movement of their arms. Upper-limb spasticity can also be painful.

Presentation of spasticity in the upper limb

Upper-limb spasticity can force the arm into an uncomfortable position, where there is:

  • Rotation of the shoulder
  • Flexion of the elbow and wrist
  • Clenched fist
  • The arm forced up against body.

Many people with muscle spasticity have increased muscle tone. In this case, muscles may never fully relax, and can remain contracted. This increased tone, also known as hypertonia, can range from mild and uncomfortable, to severe and debilitating rigidity. Hypertonia is a most common affliction of the upper limb. This results in constantly flexed elbow, bent wrist, and/or clenched fist.

Figure 1: Presentation of spasticity in the upper limb.

Hyperreflexia (exaggerated reflexes), can occur when a reflex arc is activated.

Examples include:

  • Patellar tendon reflex
  • Recoil reaction to touching a hot stove.

Clonus can occur when this reflex repeats itself over and over again.

These signs of upper limb spasticity can lead to difficulty with posture and positioning. This can largely impact the patient’s daily functioning and activities.


People suffering from upper limb spasticity experience a number of symptoms, including:

  • Muscle stiffness
  • Limited movement
  • Inability to relax muscles
  • Pain
  • Changes in limb position
  • Muscle spasms.

It can interfere with upper limb movement, and limits use of the limb for active functional tasks.

It can also cause involuntary movements (associated reactions) that impact on mobility (gait, balance, walking speed, etc.).

In severe cases, it can also impede passive function, such as washing, dressing and caring for the affected limb, thereby increasing the burden on caregivers [6,7].

Symptoms can range from mild to severe, and treatments will vary based on the patient’s specific situation. 

Damage occurring after stroke, may affect signals from the brain travelling along motor pathways to the muscles.


Although there are multiple causes for upper limb spasticity, the most common cause is a stroke. Approximately 17% to 38% of patients experienced poststroke upper limb spasticity [1-5,26,28,29].  It is more prevalent in younger patients [2], and most commonly affects the upper limb [6].

Other conditions causing upper limb spasticity include:

  • Traumatic brain injuries (TBI ~20% of patients)
  • Adult Cerebral palsy
  • Multiple sclerosis
  • Problems with the spinal cord.

Multiple therapeutic interventions including stretching, casting, splinting, pharmacologic treatment, BoNT-A injection, and electrical stimulation of the muscles, have been tried for abating spasticity that mostly involves the peripheral nerves and muscles [4–6].

Spasticity is considered a neural lesion when:

  • The primary lesion leading to the spasticity is located in the central nervous system
  • When attention to the structural and functional changes in skeletal muscle occur secondarily to the spasticity

It is also a common condition among survivors of traumatic brain injury (TBI) and occurs in up to 20% of patients with moderate-to-severe TBI [15].

Up to 20% of patients with TBI develop an acute subdural hematoma [16], a condition that may be associated with contralateral spastic hemiplegia, a lesion whose physiopathology is similar to that of brain lesions of vascular origin [17].

When a lesion of the brainstem is involved, spasticity becomes more pronounced [18]. Spasticity occurs more commonly in upper limbs than lower limbs [19]. Upper limb function is severely compromised by spasticity owing to decreased range of motion, decreased voluntary strength, and increased joint stiffness [20, 23].

BoNT-A Injections

BoNT-A injections for the treatment of upper limb spasticity, can offer patients relief from their symptoms. This occurs by blocking nerve receptors in the muscles, causing them to relax while alleviating pain.

Overall, BoNT-A, proved effective in several placebo-controlled studies reducing muscle tone, easing hand hygiene, and improving upper limb motor functions. The effects are reversible, and the toxin is generally well tolerated.

There a well-established body of evidence demonstrating that BoNT-A is a well-tolerated and effective focal intervention for the reduction of spasticity, and it is widely recommended for use in standard clinical practice [7–10].

Controlled clinical trials [11–20] have confirmed the benefits of BoNT-A at the level of impairment, but functional change has been harder to demonstrate.  While clinical experience suggests that some patients make substantial functional gains, the question of which patients are most likely to benefit and in what way, is yet to be established [23].  

Although BoNT-A is an effective treatment for upper limb spasticity, it can take time for a patient to feel results. BoNT effects a local paresis where the reversible effects start approximately one week after the injection. The effect can last 3 to 4 months. The basic aim is to selectively weaken the muscles responsible for the spastic deformity.

Studies show that patients who received regular BoNT treatments, with the help of physical and occupational therapy, showed improved upper limb function after two years of continual treatment.

Studies have also shown that repeated BoNT injection over a period of 3 years effected an unchanging effectiveness in the management of focal upper limb spasticity after stroke [13].

Task-specific repetitive therapy following successful treatment of focal spasticity is thought to support improvements with respect to disability.

The Value of EMG Guidance in the Management of Upper Limb Spasticity

There are many compelling reasons to use EMG guidance. The first is that EMG ensures that the needle is located in a muscle. The second is confirmation that the needle is in a muscle that is actively contracting in association with the disorder.   Speelman and Brans showed that even the most experienced “blind” injectors were frequently inaccurate in identifying needle placement in muscles of the neck [22].

The error rate ranged from 15% in an easily palpated superficial cervical muscle, such as sternocleidomastoid, to greater than 50% in deeper muscles, such as levator scapulae and semispinalis capitis [23].

Comella and colleagues illustrated that BoNT injection for spasmodic torticollis increased magnitude of benefit with electromyographic assistance. The article involved comparing experienced investigators using EMG versus palpation and showed that EMG was superior in terms of reducing side effects and obtaining clinical benefit [24].

Recent studies showed that both expert and novice needle placements improve with guidance when compared without, even in large easily accessible muscles [25].

These studies clearly illustrate that we all do better finding the optimal spots to locate the needles when using EMG guidance, regardless of whether the muscle is located easily on the surface, or deeper, or whether the needle insertions are being carried out by novice or experts.  

Myoguide is equipped with what is essentially a single channel EMG machine with a full featured, built in stimulator.

Myoguide™ EMG/ESTIM BoNT injection guidance system is designed to amplify EMG signals from muscle and provide audio and visual feedback to assist clinicians in locating areas of muscle activity.

Benefits include:

  • Integration of a well featured stimulator,
  • Ability to stimulate in either 1.0 mA or 0.1 mA steps

This is useful for muscle, nerve, and motor endplate location procedures provides. This also provides useful clinical support for both stimulation location and ultrasound procedures.

Myoguide supports injection of neuromodulators and both chemodenervation and neurolytic procedures, as well as, peripheral nerve stimulation.

The Value of Electrical Stimulation (ESTIM) Guidance in the Management of Upper Limb Spasticity

Electrical stimulation (ESTIM) guidance increases the accuracy of hypodermic needle electrode placement, compared to simply using anatomical knowledge (AKO) placement by using muscle activation.

The potential advantage of ESTIM is that not only does it ensure that the injecting needle is in the target muscle, but that the needle is in close proximity to motor endplates and/or motor points [27].  Electrical stimulation is easy to perform, does not require formal training, and does not prolong the procedure significantly.

However, it does require experience/practice in electrophysiological techniques as well as familiarity with the relevant anatomical landmarks, which we assume is the standard of practice.

While it has been proven that EMG guidance does perform consistently better than AKO approaches, even in large muscles [24,25], ESTIM is useful, in particular applications, and certainly within the hand, for validation before injection of BoNT.

In the case where there are multiple smaller muscles present in the vicinity, especially when dealing with the hand, ESTIM provides a simple way to double check that EMG is actually coming from the expected muscle.  Please have a look at some of our clinical videos on this subject.

Myoguide’s stimulator presents:

  • 5 stimulation frequency choices
  • 4 pulse width choices
  • 1- 20 mA of stimulation current available in both 1.0 mA and 0.1 mA steps.

0.1 mA steps are helpful and necessary for nerve location procedures allow evoking responses at lower, more comfortable stimulation levels.  

Pulse widths of up to 500 microseconds allow evoking muscle twitches at lower currents, yielding a more comfortable clinical experience for patients undergoing stimulation location procedures.

Wider stimulation choices allow evoking twitch at lower, more comfortable stimulation levels. 

Myoguide has an exclusive feature, “Stimulation Pause” which allows clinicians to easily halt the stimulation process.  This is especially useful when repositioning the injection needle electrode in order to fine tune its location for a more accurate injection point.  Stimulation can easily be returned to the pre-paused current level with the touch of any button.

The goal is to validate that the needle tip location is within the correct muscle, by being able to witness the twitch in the correct location.  The needle is easily partially withdrawn and repositioned for another try, if corrections are needed.

Myoguide™ EMG/ESTIM BoNT injection guidance system is designed to amplify EMG signals from muscle and provide audio and visual feedback to assist clinicians in locating areas of muscle activity.

Myoguide also has an integrated and well featured stimulator, capable of stimulation in either 1.0 mA or 0.1 mA steps, for muscle, nerve, and motor endplate location procedures.

Myoguide supports injection of neuromodulators and both chemodenervation and neurolytic procedures, as well as, peripheral nerve stimulation. Learn more about how to use Myoguide

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