title: Computer-tomographic verification of ultrasound-guided piriformis muscle injection: a feasibility study.
abstract: BACKGROUND
  Approximately 6% to 8% of lumbar pain cases, whether associated with radicular pain or not, may be attributed to the presence of piriformis muscle syndrome. Available treatments, among others, include pharmacotherapy, physical therapy, and injections of different substances into the muscle. Various methods have been used to confirm correct needle placement during these procedures, including electromyography (EMG), fluoroscopy, computed tomography (CT), or magnetic resonance imaging (MRI). Ultrasonography (US) has now become a widely used technique and therefore may be an attractive alternative for needle guidance when injecting this muscle.
  
  
  OBJECTIVE
  The objective of this study was to assess the reliability of US in piriformis injection of patients with piriformis syndrome.
  
  
  METHODS
  Feasibility study; 10 patients with piriformis muscle syndrome were injected with botulinum toxin A using a US-guided procedure. Then patients were administered 2 mL iodinated contrast and were then transferred to the CT scanner, where they underwent pelvic and hip imaging to assess intramuscular distribution of the iodinated contrast.
  
  
  METHODS
  Multidisciplinary Pain Management Department in Spain.
  
  
  RESULTS
  Of all 10 study patients (8 women, 2 men), 9 had intramuscular or intrafascial contrast distribution. Distribution did not go deeper than the piriformis muscle in any of the patients. The absence of contrast (intravascular injection) was not observed in any case.
  
  
  CONCLUSIONS
  The main limitation of our study is the use of ionizing radiation as confirmation technique.
  
  
  CONCLUSIONS
  Ultrasound-guided puncture may be a reliable and simple procedure for injection of the piriformis muscle, as long as good education and training are provided to the operator. US has a number of advantages over traditional approaches, including accessibility and especially no ionizing radiation exposure for both health care providers and patients.
authors.affiliation: Anesthesiologist, Multidisciplinary Pain Management Department, General University Hospital, Valencia, Spain; General Practitioner, Multidisciplinary Pain Management Department, General University Hospital, Valencia, Spain; Head of Radiology Department, G.
authors.forename: Gustavo
authors.initials: G
authors.lastname: Fabregat
authors.forename: Marta
authors.initials: M
authors.lastname: Roselló
authors.forename: Juan Marcos
authors.initials: JM
authors.lastname: Asensio-Samper
authors.forename: Vincent Luis
authors.initials: VL
authors.lastname: Villaneuva-Pérez
authors.forename: Vicente
authors.initials: V
authors.lastname: Martínez-Sanjuan
authors.forename: José
authors.initials: J
authors.lastname: De Andrés
authors.forename: Urs
authors.initials: U
authors.lastname: Eichenberger
mesh_terms: D000328:Adult; D019274:Botulinum Toxins, Type A / Q000008:administration & dosage* / Q000494:pharmacology; D003287:Contrast Media / Q000008:administration & dosage / Q000493:pharmacokinetics*; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D007273:Injections, Intramuscular / Q000379:methods; D008297:Male; D008875:Middle Aged; D009465:Neuromuscular Agents / Q000008:administration & dosage* / Q000494:pharmacology; D055958:Piriformis Muscle Syndrome / Q000188:drug therapy*; D014057:Tomography, X-Ray Computed / Q000379:methods*; D014463:Ultrasonography / Q000379:methods / Q000592:standards*
chemical_list: D003287:Contrast Media; D009465:Neuromuscular Agents; D019274:Botulinum Toxins, Type A