title: Insights into the Functional Anatomy Behind the PREEMPT Injection Paradigm: Guidance on Achieving Optimal Outcomes.
abstract: OBJECTIVE
  To provide clinically relevant insights on the identification of the muscles and techniques involved in the safe and effective use of onabotulinumtoxinA for chronic migraine prophylaxis.
  
  
  BACKGROUND
  Although guidance on the use of onabotulinumtoxinA for chronic migraine is available, based on the Phase III Research Evaluating Migraine Prophylaxis Therapy (PREEMPT) clinical program, clinical experience has shown that insufficient understanding of the anatomy and function of the head and neck muscles may lead to undesirable outcomes and suboptimal efficacy.
  
  
  METHODS
  Each muscle involved in the standardized PREEMPT injection paradigm is reviewed with a thorough description of each muscle's anatomy (ie, muscle description and location, innervation, vascular supply) and function. Key insights based on clinical experience are also provided to help improve outcomes.
  
  
  RESULTS
  The identification of the muscles in the PREEMPT injection paradigm should be based on each patient's unique anatomy and injections should be administered using the advised techniques. A thorough examination of the patient prior to treatment is also critical to determine if any preexisting conditions may increase the risk for unwanted outcomes and appropriate expectations should be communicated.
  
  
  CONCLUSIONS
  Thorough knowledge of the functional anatomy of the muscles involved in the standardized PREEMPT injection paradigm is critical to achieve the efficacy and safety observed in clinical trials. In addition, it is important to assess a patient's baseline condition to anticipate the risk for unwanted outcomes that may result from treatment.
authors.affiliation: Neurology Center, Encinitas, CA, USA.
authors.forename: Andrew M
authors.initials: AM
authors.lastname: Blumenfeld
authors.affiliation: Jefferson Headache Center, Department of Neurology, Thomas Jefferson University, Philadelphia, PA, USA.
authors.forename: Stephen D
authors.initials: SD
authors.lastname: Silberstein
authors.affiliation: Department of Neurology, Mayo Clinic, Phoenix, AZ, USA.
authors.forename: David W
authors.initials: DW
authors.lastname: Dodick
authors.affiliation: Department of Neurology, Stanford University, Stanford, CA, USA.
authors.forename: Sheena K
authors.initials: SK
authors.lastname: Aurora
authors.affiliation: Allergan plc, Irvine, CA, USA.|Department of Neurology, University of California at Irvine, Irvine, CA, USA.
authors.forename: Mitchell F
authors.initials: MF
authors.lastname: Brin
authors.affiliation: Department of Head and Neck Surgery, University of California at Los Angeles, Los Angeles, CA, USA.
authors.forename: William J
authors.initials: WJ
authors.lastname: Binder
mesh_terms: D065087:Acetylcholine Release Inhibitors / Q000008:administration & dosage / Q000494:pharmacology*; D019274:Botulinum Toxins, Type A / Q000008:administration & dosage / Q000494:pharmacology*; D005152:Facial Muscles / Q000033:anatomy & histology / Q000187:drug effects; D006801:Humans; D007273:Injections, Intramuscular / Q000592:standards*; D008881:Migraine Disorders / Q000188:drug therapy*; D018482:Muscle, Skeletal / Q000033:anatomy & histology* / Q000187:drug effects; D009334:Neck Muscles / Q000033:anatomy & histology / Q000187:drug effects; D017410:Practice Guidelines as Topic / Q000592:standards*
chemical_list: D065087:Acetylcholine Release Inhibitors; D019274:Botulinum Toxins, Type A
keywords: chronic migraine; clinical; injection technique; onabotulinumtoxinA