Mechanical evaluation of four- versus eight-pin halo fixation.
Fixation of the halo device in the skulls of young children is sometimes compromised because of a thinner cortex and the increased jarring and trauma that small children experience during their everyday activities of life at that age. To assess the increased fixation that an eight-pin halo fixation would provide over the more standard four-pin fixation, the stiffness of fixation of a halo orthosis was evaluated in four dried human cadaver skulls. Two different fixation systems were used: the first one with four pins in the standard locations and the second with four additional pins. A compressive force was applied to the halo ring at a constant rate of 1.27 mm/min. Load and deflection data were recorded simultaneously until a force of 400 N was reached. Results for the two-pin systems were analyzed and compared statistically by using paired t tests. Statistically significant differences were established between the two sets of results with the 8-pin system providing an increase of 24.2% in the stiffness of fixation.
Letts
M
M
Department of Surgery, Children's Hospital of Eastern Ontario, Ottawa, Canada.
Girouard
L
L
Yeadon
A
A
D001696:Biomechanical Phenomena; D002102:Cadaver; D004869:Equipment Safety; D006801:Humans; D008962:Models, Theoretical; D012886:Skull; D016103:Spinal Fractures / Q000628:therapy; D013523:Surgical Equipment; D014143:Traction / Q000295:instrumentation* / Q000379:methods