To report the severity of orbital implant infection related to a drilling procedure and to provide a foundation for reevaluating this procedure.

We investigated retrospectively 17 patients who were suspected of orbital implant infection and whose infected implants were ultimately removed. In these patients, increased mucopurulent eye discharge and implant exposure after the drilling procedure were observed. We attempted to treat them with topical and systemic antibiotics, but the discharge and implant exposure did not improve.

Of the 17 removed implants, 13 were hydroxyapatite and 4 were Medpor^®. The pegs used were plastic pegs in 12 cases and titanium pegs in 5 cases. The average duration from the first orbital implant insertion to drilling was 10.2±5.3 months. The average duration from drilling to severe infection symptoms was 37.0±30.0 months. The average duration from the onset of symptoms to implant removal was 12.9±12.6 months. The mean follow-up period after final surgery was 15.4 months. In most cases, the deep portions of the removed implants were fragile, malodorous, and filled with pus. Acute and chronic inflammatory cell infiltrations were observed in the pathological examinations, and H. influenzae, S. aureus, S. viridans were identified. They did not receive any drilling procedure thereafter and no infection or inflammatory sign was subsequently observed.

Drilling and pegging can cause unexpected, severe complications such as orbital implant infection, in which the infected implant has to be removed to be cured. Therefore, before performing a drilling procedure doctors should carefully consider the patient's preferences and urgent needs.