title: Effect of sequential hole enlargement on cortical bone temperature during drilling of 6.2-mm-diameter transcortical holes in the third metacarpal bones of horse cadavers.
abstract: OBJECTIVE
  To compare the bone temperature and final hole dimensions associated with sequential overdrilling (SO) and single 6.2-mm drill bit (S6.2DB) methods used to create transcortical holes in the third metacarpal bones (MCIIIs) of horse cadavers.
  
  
  METHODS
  60 MCIIIs from 30 horse cadavers.
  
  
  METHODS
  In phase 1, hole diameter, tap insertion torque, peak bone temperature, and postdrilling bit temperature for 6.2-mm-diameter holes drilled in the lateral or medial cortical region of 12 MCIIIs via each of three 2-bit SO methods with a single pilot hole (diameter, 3.2, 4.5, or 5.5 mm) and the S6.2DB method were compared. In phase 2, 6.2-mm-diameter transcortical holes were drilled via a 2-bit SO method (selected from phase 1), a 4-bit SO method, or a S6.2DB method at 1 of 3 locations in 48 MCIIIs; peak bone temperature during drilling, drill bit temperature immediately following drilling, and total drilling time were recorded for comparison.
  
  
  RESULTS
  Hole diameter or tap insertion torque did not differ among phase 1 groups. Mean ± SD maximum bone temperature increases at the cis and trans cortices were significantly less for the 4-bit SO method (3.64 ± 2.01°C and 8.58 ± 3.82°C, respectively), compared with the S6.2DB method (12.00 ± 7.07°C and 13.19 ± 7.41°C, respectively). Mean drilling time was significantly longer (142.9 ± 37.8 seconds) for the 4-bit SO method, compared with the S6.2DB method (49.7 ± 24.3 seconds).
  
  
  CONCLUSIONS
  Compared with a S6.2DB method, use of a 4-bit SO method to drill transcortical holes in cadaveric equine MCIIIs resulted in smaller bone temperature increases without affecting hole accuracy.
authors: Department of Veterinary Clinical Sciences, School of Veterinary Medicine, Purdue University, West Lafayette, IN 47907, USA. tlescun@purdue.edu
authors: Timothy B
authors: TB
authors: Lescun
authors: Elizabeth A
authors: EA
authors: Frank
authors: Joshua R
authors: JR
authors: Zacharias
authors: Joanne K
authors: JK
authors: Daggy
authors: George E
authors: GE
authors: Moore
mesh_terms: D000818:Animals; D001696:Biomechanical Phenomena; D002102:Cadaver; D006736:Horses; D006358:Hot Temperature; D050279:Metacarpal Bones / Q000601:surgery*; D019637:Orthopedic Procedures / Q000379:methods*; D013314:Stress, Mechanical; D019415:Torque