The Carshalton halo-pelvic traction apparatus.

The 'Hong Kong' halo-pelvic traction frame is widely used for correcting spinal deformation and as a holding apparatus for spinal operations. A study at Queen Mary's Hospital for Children, Carshalton, suggested that there were considerable possibilities for improvement. Firstly the supporting rods are cranked and do not apply the forces in a linear mode, whilst a reduction in the number of flexible joints would improve stability. Secondly, and more important, the accuracy of the measurement of forces applied is capable of considerable improvement and this would markedly reduce the possibility that undesirably large forces could be used. An improved frame has now been designed, manufactured and tested intensively. In this new design the supporting rods are straight whilst the forces applied are measured by means of potentiometric sensor in each rod, with read-out on a meter calibrated in kilograms. The frame has been fitted to one patient with satisfactory results.