Review Question - QID 3720

The patient has developed a superficial pin site infection. Since the patient is afebrile and there is no loosening of the pin, the best management of the infection at this time is to leave the pin in place and start the patient on oral antibiotics.

Infection at the pin site is a common complication of the halo device, occurring in about 12-20% of patients. Infection can be either superficial or deep. Superficial infections can be treated with oral antibiotics and wound care at the pin site. If a deep infection develops, the pin should be removed. If an abscess develops, parenteral antibiotics and drainage of the abscess may be necessary. Another common complication of halo device fixation is pin loosening. Pin loosening does not always occur with pin site infection. If there is no infection present, a loose pin can be managed by simply retightening the screw. Additional complications from halo fixation include skin breakdown, intracranial penetration and nerve palsies. An abducens nerve (CN VI) palsy is the most frequently reported palsy with halo fixation and results in loss of lateral gaze on the affected side (see Illustration C).

van Middeindorp et al. reported on the complications associated with halo-vest immobilization in a prospective cohort of 239 patients who treated at a level-I trauma center over a 5-year period. They reported that 29 patients (12%) developed pin site infections, which was the most common complication and was associated with pin penetration through the outer table of the skull (odds ratio, 4.34; 95% confidence interval, 1.22 to 15.51; p = 0.024).

Garfin et al. described a retrospective cohort of 179 patients who were treated with halo-vest immobilization. Pin loosening was the most common complication, occurring in 37% of patients, followed by pin-site infection, which was diagnosed in 20% of patients. They reported that two-thirds of the pins that were loose or associated with infection required change or removal.

Illustration A shows the safe zone of anterior pin placement. Illustration B shows the nerve structure one must be aware of. Illustration C shows the clinical presentation of an abducens nerve palsy which is considered to be a traction injury of the abducens nerve, which is an intracranial structure.

Incorrect Answers
Answer 1 & 2: A superficial wound infection does not always require removal of the pin.
Answer 3: The pin is not loose, so it should not be tightened; in fact, this may lead to penetration of the outer table of the skull.
Answer 5: Although local pin site wound care is needed, oral antibiotics should also be started in this situation.