title: Exploring thermal anisotropy of cortical bone using temperature measurements in drilling.
abstract: BACKGROUND
  Bone drilling is widely used in orthopaedics for fracture treatment, reconstructive surgery and bone biopsy. Heat generation in bone drilling can cause rise in bone temperature resulting in prolonged healing time or loosening of fixation.
  
  
  OBJECTIVE
  The purpose of this study was to investigate thermal anisotropy of bone by measuring the level of temperature in bone drilling with and without cooling conditions in two anatomical directions.
  
  
  METHODS
  Drilling tests were performed on bovine cortical bone. A total of fifteen specimens were used to obtain data for statistical analysis. Temperature near the cutting zone was measured in two anatomical directions. i.e. along the longitudinal and circumferential direction. Temperature distribution was also found in the two prescribed directions. Analysis of variance (ANOVA) was used to identify significant drilling parameter affecting bone temperature.
  
  
  RESULTS
  Drilling speed, feed rate and drill size were found influential parameters affecting bone temperature. Higher drilling speed, feed rate, and large drill size were found to cause elevated temperature in bone. Much lower temperature was measured in bone when cooling fluid was supplied to the drilling region. Experimental results revealed lower temperatures in the circumferential direction compared to the longitudinal direction.
  
  
  CONCLUSIONS
  Thermal anisotropy for heat transport was found in the bone. This study recommends lower drilling speed and feed rate and cooling for controlling rise in bone temperature.
authors.affiliation: Department of Mechanical and Industrial Engineering, College of Engineering, Sultan Qaboos University, P.O. Box 33, 123, Sultanate of Oman. Tel.: +(968) 24143751; Fax: +(968) 24141316; E-mail: kalam@squ.edu.om.
authors.forename: Khurshid
authors.initials: K
authors.lastname: Alam
mesh_terms: D000818:Animals; D016880:Anisotropy; D001831:Body Temperature; D002417:Cattle; D000071538:Cortical Bone / Q000502:physiology* / Q000601:surgery*; D006358:Hot Temperature; D019637:Orthopedic Procedures / Q000379:methods*; D013696:Temperature
keywords: Orthopaedic; bone drilling; experimental analysis; necrosis; thermocouple