title: An investigation into the production of intra-articular gas bubbles and increase in joint space in the zygapophyseal joints of the cervical spine in asymptomatic subjects after spinal manipulation.
abstract: OBJECTIVE
  To analyze the size and density of cervical zygapophyseal joint spaces in asymptomatic subjects using computed tomography (CT) and plain film radiography. The joint spaces were analyzed before manipulation without traction, before manipulation with manual traction, after manipulation without traction, and after manipulation with manual traction. The data obtained before the manipulation were compared with data obtained after the manipulation to determine if significant alterations occurred.
  
  
  METHODS
  Twenty-two asymptomatic subjects were placed into 1 or more of 6 possible experimental groups. In all experimental groups, except for experiment 1, the subjects underwent: (step 1) a premanipulation radiograph and/or CT scan, (step 2) a premanipulation plus traction radiograph and/or CT scan, (step 3) a postmanipulation radiograph and/or CT scan, and (step 4) a postmanipulation plus traction radiograph and/or CT scan.
  
  
  RESULTS
  Except for experiment 2, there was no significant change in the width, area, and density values of the zygapophyseal joint spaces immediately after the manipulation in either the traction or traction-free positions of the neck, and no visible radiolucent cavities were demonstrated in any view.
  
  
  CONCLUSIONS
  No evidence of gas in the joint space or obvious increase in zygapophyseal joint space width immediately after the manipulation was found. This was evident in both the traction and traction-free postmanipulation scans and plain film images. This is not consistent with the current understanding of cavitation in joints, in particular, the refractory period.
authors.affiliation: Welsh Institute of Chiropractic, Wales, UK. vcasciol@glam.ac.uk
authors.forename: Vincenzo
authors.initials: V
authors.lastname: Cascioli
authors.forename: P
authors.initials: P
authors.lastname: Corr
authors.forename: A G
authors.initials: AG
authors.lastname: Till Ag
mesh_terms: D000328:Adult; D002574:Cervical Vertebrae / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D005260:Female; D006801:Humans; D008297:Male; D020393:Manipulation, Spinal / Q000379:methods*; D011859:Radiography; D016059:Range of Motion, Articular; D013997:Time Factors; D014143:Traction; D021801:Zygapophyseal Joint / Q000503:physiopathology*