title: Factors affecting the integrity of latissimus dorsi muscle grafts: implications for cardiac assistance from skeletal muscle.
abstract: BACKGROUND
  Severe latissimus dorsi muscle damage may compromise cardiomyoplasty performance. We analyzed factors underlying the damage produced in 20 sheep latissimus dorsi muscles by isolating the influences of electrical stimulation, mobilization (with some loss of vascular supply), loss of normal resting tension, or a combination of these.
  
  
  METHODS
  In group I (n = 3), the muscle was mobilized except for its neurovascular pedicle and reattached at normal resting length. In group II (n = 3), the muscle was mobilized and reattached at about 80% of resting length. Groups III (n = 6) and IV (n = 4) were as groups I and II except that continuous indirect stimulation at 2 Hz was added after 2 weeks. In group V (n = 4), the undisturbed muscle received stimulation alone. After 10 to 12 weeks, muscle samples were taken for morphometric analysis.
  
  
  RESULTS
  Loss of resting muscle tension appeared to be the single most damaging intervention, though mobilization and stimulation had further deleterious effects. The worst damage was seen when all three factors were combined, when 60% of the muscle cross section was occupied by connective tissue and fat. The changes were significantly more severe in the distal than in the proximal part of the muscle, implicating ischemia as a contributory factor.
  
  
  CONCLUSIONS
  Fiber damage reduces the effectiveness of muscle grafts used for cardiac assistance and merits further systematic investigation.
authors.affiliation: Department of Cardiothoracic Surgery, Wythenshawe Hospital, Manchester, United Kingdom.
authors.forename: R M
authors.initials: RM
authors.lastname: el Oakley
authors.forename: J C
authors.initials: JC
authors.lastname: Jarvis
authors.forename: D
authors.initials: D
authors.lastname: Barman
authors.forename: D L
authors.initials: DL
authors.lastname: Greenhalgh
authors.forename: J
authors.initials: J
authors.lastname: Currie
authors.forename: D Y
authors.initials: DY
authors.lastname: Downham
authors.forename: S
authors.initials: S
authors.lastname: Salmons
authors.forename: T L
authors.initials: TL
authors.lastname: Hooper
mesh_terms: D000273:Adipose Tissue / Q000473:pathology; D000818:Animals; D018421:Cardiomyoplasty; D003238:Connective Tissue / Q000473:pathology; D009119:Muscle Contraction / Q000502:physiology; D018485:Muscle Fibers, Skeletal / Q000473:pathology; D018482:Muscle, Skeletal / Q000098:blood supply / Q000473:pathology* / Q000503:physiopathology*; D015427:Reperfusion Injury / Q000473:pathology; D012756:Sheep