Volumetrics and abscess-to-orbit ratio in surgically managed subperiosteal abscesses

Management of subperiosteal abscesses complicating orbital cellulitis is based on clinical and radiological presentations but remains heterogeneous without clear criteria for surgical indication. Retrospective review of severe cases of subperiosteal abscesses requiring surgical management at Nancy University Hospital between May 2022 and August 2023. Volumetric data of the subperiosteal abscesses and orbit on preoperative CT scans were obtained using a semi-automatic and manual segmentation software (ITK-SNAP). Seven male patients were admitted for surgical drainage of a subperiosteal orbital abscess following sinusitis. One patient had an additional retro-ocular intraconal orbital abscess, and two patients had major intracranial complications such as subdural empyema and required subsequent neurosurgical management. The mean age was 19.9 years old (range 11–48, median 16 years old). Five patients had ophthalmological signs on presentation, such as blurring, diplopia, or pupillary deficit. The mean volume of subperiosteal abscesses before surgery was 3.82 cm3 for a mean orbital volume of 31.70 cm3, with a mean abscess-to-orbit volume ratio of 11.7% (range 3–27%). Radiological findings such as volume or an abscess-to-orbit ratio could be useful to identify patients with subperiosteal orbital abscesses with surgical indication, especially when there are no clinical signs of severity.