title: Investigation of abdominal muscle thickness changes after spinal manipulation in patients who meet a clinical prediction rule for lumbar stabilization.
abstract: METHODS
  Prospective case series.
  
  
  OBJECTIVE
  To investigate changes in abdominal muscle thickness with ultrasound imaging, after spinal manipulative therapy (SMT), in a subgroup of patients with low back pain (LBP) who meet a proposed clinical prediction rule for lumbar stabilization exercise (LSE).
  
  
  BACKGROUND
  The characteristics of a subgroup of patients with LBP who respond clinically to LSE has been proposed. Although the pathoanatomical characteristics of this subgroup have not been determined, clinicians often assume that this type of LBP is related, in part, to neuromuscular deficits of the lateral abdominal muscles. Recent evidence suggests that SMT may facilitate abdominal muscle activity and, therefore, enhance exercises targeting these deficits.
  
  
  METHODS
  Nineteen patients (mean age ± SD, 32.5 ± 7.8 years; 11 female) with LBP, who met the criteria for LSE, underwent ultrasound imaging of the transversus abdominis (TrA) and internal oblique (IO) muscles before, immediately after, and 3 to 4 days after lumbopelvic SMT. Measurements of resting thickness, contracted thickness during the abdominal drawing-in maneuver, and percent thickness change from rest to contraction of the TrA and IO muscles were analyzed with repeated-measures analysis of variance. Numeric pain rating scale and Oswestry Disability Index data were also collected.
  
  
  RESULTS
  No significant differences in resting, contracted, or percent thickness change in the TrA or IO were found over the 3 time periods. There were statistically significant reductions in numeric pain rating scale and Oswestry Disability Index scores, but mean differences failed to meet the minimal clinically important difference.
  
  
  CONCLUSIONS
  The results provide preliminary evidence that TrA and IO muscle resting and contracted thicknesses do not change post-SMT in patients with LBP in the LSE subgroup. In addition, while reductions in pain and disability were noted, they were not clinically meaningful.
authors.affiliation: Robinson Health Clinic Physical Therapy, Womack Army Medical Center, Fort Bragg, NC, USA. lisa.konitzer@us.army.mil
authors.forename: Lisa N
authors.initials: LN
authors.lastname: Konitzer
authors.forename: Norman W
authors.initials: NW
authors.lastname: Gill
authors.forename: Shane L
authors.initials: SL
authors.lastname: Koppenhaver
mesh_terms: D000009:Abdominal Muscles / Q000033:anatomy & histology* / Q000000981:diagnostic imaging; D000328:Adult; D005260:Female; D006801:Humans; D017116:Low Back Pain / Q000000981:diagnostic imaging / Q000628:therapy*; D008297:Male; D020393:Manipulation, Spinal; D009119:Muscle Contraction / Q000502:physiology; D009929:Organ Size; D010147:Pain Measurement; D012720:Severity of Illness Index; D014463:Ultrasonography