Experimental investigation of halo-gravity traction for paediatric spinal deformity correction

Paediatric spinal deformities pose much difficulty for orthopaedic surgeons. Halo-gravity traction using threaded stainless steel pins with a graphite halo device mounted to the skull has been successful, but is invasive and must be tailored specifically to each individual patient. Experimental and clinical testing in paediatrics has been performed to evaluate the halo-gravity traction method of correction to optimise required number of pins, and pin-torque loading parameters, with differing results. For paediatrics, surgeons do not apply loading exceeding 50% of a child's body weight. The current study experiments with six and ten pin halo configurations under applied torque loading of 226, 452 and 678 Newton-millimetre (2, 4 and 6 inch-pound) to determine failure loading of the halo system. The results indicate that the failure load of the sawbone skulls far exceeds the average weight of a paediatric patient.