title: Changes of blood circulation of the extremity after external fixation for tibia shaft defect: an experimental study.
abstract: OBJECTIVE
  To assess and compare two approaches, end to end compression with lengthening (EECL) and segmental bone transport by lengthening (STBL), for long tubular bone defect and nonunion.
  
  
  METHODS
  Ten goats were used to establish the bone defect model of the mid-tibia. The bone defect ends were shortened step by step with a sulcated half-ring external fixator. Changes of the blood flow of the distal extremity were measured with pulse-Doppler monitor and angiography.
  
  
  RESULTS
  The blood flow in the distal extremity was not affected when bone defect was less than 15% of the original length. Blood circulatory disorder would appear in the distal extremity when bone defect ranged 15%-20% of the original length. The necrosis would appear in the extremity because of the blood circulatory obstacle when bone defect was more than 20% of the original length.
  
  
  CONCLUSIONS
  EECL is an appropriate alternative of treatments if bone defect is less than 15%; while SBTL may be feasible if bone defect is over 20% of the original length. When bone defect ranges between 15% and 20%, EECL should be applied with great care on condition of keeping watch on the extremity circulation with pulse-Doppler monitor.
authors.affiliation: Department of Orthopedics, Southwest Hospital, Third Military Medical University, Chongqing, 400038, China.
authors.forename: L
authors.initials: L
authors.lastname: Yang
authors.forename: Q
authors.initials: Q
authors.lastname: Li
authors.forename: Z
authors.initials: Z
authors.lastname: Zhou
mesh_terms: D000792:Angiography; D000818:Animals; D001775:Blood Circulation / Q000502:physiology*; D006041:Goats; D009984:Orthopedic Fixation Devices; D012039:Regional Blood Flow / Q000502:physiology*; D013977:Tibia / Q000098:blood supply* / Q000000981:diagnostic imaging