The present pilot study is designed to assess the extent to which BOTOX and MYOBLOC cause muscle atrophy in spastic patients. The primary objective is to assess whether there is statistically significant difference in muscle atrophy between the two groups over a one year period.

Botulinum toxin has long been used as a clinical application for the treatment of overactive skeletal and smooth muscles, i.e. spasticity. The benefits of botulinum therapy are indisputable, however, muscle atrophy is one main adverse effect that may hinder a patient's strength and decrease the ability for the practitioner to accurately administer botulinum toxin to a specific muscle group. This, in turn may cause unintentional weakness of adjacent muscle groups through inaccurate targeting or diffusion of botulinum toxin. Currently, only two serotypes (abbreviated to BTX-A (BOTOX, XEOMIN and DYSPORT) and BTX-B (MYOBLOC), respectively) are used in clinical practice for spasticity. Research has shown that both BTX-A and BTX-B are efficacious in the treatment of spasticity. However, there is no documented literature evaluating if there is a statistically significant difference in the degree of muscle atrophy using BTX-A versus BTX-B.

Inclusion Criteria:

• Men and women aged 18 or older with spasticity secondary to either a disorder or trauma, such as a spinal cord injury (SCI), a brain injury, a tumor, a stroke, multiple sclerosis (MS), or a peripheral nerve injury.
• Participants must have the ability to provide written consent to participate in the study.

Exclusion Criteria:

• Patients who have received BTX-A or BTX-B in the past in the skeletal muscle group under investigation or patients who have had an allergic response to BTX-A or BTX-B in the past.
• Diagnosis of Myasthenia gravis, Eaton-Lambert Syndrome, or Amyotrophic Lateral Sclerosis. Females who are pregnant or breastfeeding. Subjects taking Aminoglycosides or other agents interfering with neuromuscular function.