The medical records of 179 patients were reviewed to identify complications related to the use of the halo external skeletal-fixation device. The complications that were identified included pin-loosening in 36 per cent of the patients, pin-site infection in 20 per cent, pressure sores under either a plastic vest or a plaster cast in 11 per cent, nerve injury in 2 per cent, dural penetration in 1 per cent, dysphagia in 2 per cent, cosmetically disfiguring scars in 9 per cent, and severe pin discomfort in 18 per cent. One hundred and eighty (25 per cent) of the 716 pins used had become loose at least once, and an infection had developed at sixty-seven pin sites (9 per cent). Two-thirds of the pins that were loose or associated with infection required change or removal. These complication rates, particularly of pin-loosening and infection, are exceedingly high. Attention to details in pin application, pin maintenance, and proper pin-site care may minimize the number of complications.