Botox Injections Treat Poststroke Spasticity

Poststroke spasticity typically presents on the same side of the body affected by the stroke and can take several months to develop — which is long after hospital discharge and often after rehabilitation. Spasticity is due to an imbalance between flexor and extensor muscles caused by damage to neurons in the central nervous system, which controls movement, coordination and the normal tone of the extremities.

Targeted muscle injections of Botulinum Toxin type A (BTX-A), or Botox, have been utilized to assist with this uncomfortable and potentially debilitating problem, and are FDA-approved for the treatment of arms (upper limb spasticity) and legs (lower limb spasticity). Injecting Botox into the overactive/spastic muscle(s) leads to a selective weakening of the offending muscle(s) by reversibly inhibiting /reducing the release of acetylcholine in the neuromuscular junction. This neurotransmitter is crucial in leading to muscle contraction and is exactly where Botox has the effect. Partial relaxation of a spastic muscle leads to improved range of motion and pain/discomfort relief.

Biceps brachii Botox injection for spasticity

Biceps brachii Botox injection
for spasticity

The procedure is performed in the clinic using electromyographic (EMG) or electrical stimulation guidance with a hand-held device and EMG needle. “The injections are administered every twelve weeks on average, given that the toxin effects are reversible and will attenuate with time,” said Steven Kosa, MD, a neurologist with Meritas Health Neurology. He has been using Botox injections to manage poststroke spasticity for more than five years.

When spasticity is reduced, caregivers can better maintain hygiene of the involved extremities, which helps prevent skin breakdown. “Improved functionality and improved patient comfort are the main goals of the treatment,” Dr. Kosa noted.

Early Intervention

Early referral increases the success of Botox treatment, thus physicians should refer a patient at the first sign of spasticity. If spasticity is left unmanaged over time (months to years), the patient can develop contractures in the limbs, making them much more difficult to treat. It also can lead to a diminished response to Botox injections. These patients can go on to have surgical joint fusions when the contracture becomes severe.


Managing spasticity with Botox is an ongoing process, and initially, injections are required approximately every three months. The length of treatment depends on the patient’s response and the severity of the spasticity. “Some spasticity patients need injections every three months while others receive injections less frequently, once or twice per year. Patients can also improve so much that they no longer need the injections and can continue with physical therapy alone,” Dr. Kosa said.

For maximum effectiveness, Dr. Kosa recommends using Botox injections in conjunction with a physical therapy program and refers patients to North Kansas City Hospital’s physical therapy department. Limited alternative therapies include muscle relaxant medications or pain medications, which have a lot of potential systemic side effects and are not very effective at improving a focal muscle problem. Botox injections have a very beneficial side effect profile, especially with limb injections. Rarely, swallowing difficulties can arise or an extremity can become too weak after injections, but careful consideration of the case and slow dose escalation over time as needed help prevent this.

Muscle Selection

To pinpoint the overactive muscles, Dr. Kosa uses Clavis, a handheld device that provides the same functionality as the much larger EMG machine but in a mobile and more flexible format. Clavis also includes electrical stimulation through the needle, which helps identify small muscles such as those in the forearm. Ensuring appropriate muscle injection is critical to success.


Dr. Kosa encourages primary care physicians to ask him questions about spasticity management options for their poststroke patients. “Patients with poststroke spasticity are an underserved population and need treatment as early as possible,” he said. “It is important to raise the level of awareness that we now have a very effective treatment option for these patients.”

Other Uses

Botox injections are useful in treating other conditions, including:

  • Chronic migraines
  • Spinal cord injury associated spasticity
  • Cerebral palsy associated spasticity
  • Multiple sclerosis associated spasticity
  • Cervical dystonia or torticollis

Steven Kosa, MD

Steven Kosa, MDDr. Kosa received his medical training at the University of Kansas School of Medicine. He completed an internal medicine internship at Kansas University Medical Center and his neurology residency at Mayo Clinic in Minnesota. His areas of interest include treatment of neuromuscular and peripheral nerve disorders, electromyography, headache treatment and spasticity management.