Investigation of how different halos influence pin forces.
METHODS
This study investigated the effect of the size and material of halo rings on the pin force produced at the halo pin-calvarium complex.


BACKGROUND
Loosening of halo pins has been a problem with using the halo-vest apparatus to stabilize cervical spine fractures.


METHODS
One standard halo pin and seven different halo rings were used to test the anterior pin hole of each ring at a constant torque of 8 inch-pounds (0.9 Nm).


RESULTS
Pin force fluctuated from halo to halo, and decreased as the nut was tightened.


CONCLUSIONS
Identical torques applied to different halos will not guarantee the same magnitude of pin force for halo fixation.
Kerwin
G A
GA
Department of Orthopaedic Surgery, Wayne State University, Detroit, Michigan.
Chou
K L
KL
White
D B
DB
Shen
K L
KL
Salciccioli
G G
GG
Yang
K H
KH
D000497:Alloys; D000535:Aluminum; D001858:Bone Nails; D002574:Cervical Vertebrae / Q000293:injuries; D016267:External Fixators; D006108:Graphite; D006801:Humans; D012886:Skull; D016103:Spinal Fractures / Q000601:surgery; D013193:Stainless Steel; D013314:Stress, Mechanical; D014143:Traction / Q000295:instrumentation*
D000497:Alloys; D013193:Stainless Steel; D006108:Graphite; D000535:Aluminum