The effect of torque pressure on halo pin complication rates. A randomized prospective study

At Thomas Jefferson University Hospital, 102 consecutive patients treated in a halo vest orthosis were randomized into one of two torque protocol groups based on their date of birth. The pins of patients who were born in even-numbered months were inserted with 8 inch-lbs of torque and those born in odd-numbered months were inserted with 6 inch-lbs. All patients were placed in an identical model halo using a standardized technique of application. The patients were followed prospectively, and all potential complications were evaluated by a member of the orthopedic attending staff, using protocols established at the onset of the study. Statistical analysis indicated no significant differences in halo pin loosening, infection, pain, or scarring between the torque protocols, but there was a trend toward a higher complication rate in the 8-inch-lbs group. There was no direct evidence of skull penetration in either group, and no patients developed a deep infection. Based on the results of this study, we conclude that insertion torque has no significant effect on halo pin complications within the ranges tested by this study. Our current protocol calls for routine insertion of halo pins with 6 inch-lbs of torque.