Wooden Foreign Body in the Skull Base: How Did We Miss It?

Timely detection of intraorbital and skull base wooden foreign bodies is crucial. Wooden foreign bodies are difficult to detect on imaging. The radiologist may fail to identify wooden foreign bodies on two thirds of initial scans and can miss them in almost one third of total cases.

A 66-year-old woman sustained a penetrating injury through the left upper eyelid with a small tree branch. The branch was immediately removed in the field, and she was provided with prompt medical care at a local hospital. Initial computed tomography (CT) scan diagnosis was "posttraumatic sinusitis," and this was treated empirically with vancomycin and piperacillin/tazobactam. On the eighth day after injury, she developed progressive swelling and pain of her eyelid with left trigeminal/supraorbital numbness and complete left ophthalmoplegia. A new CT scan showed an open "track" from the region of the left upper orbit/superior rectus to the contralateral sphenoid sinus, which raised suspicion for a retained foreign body. Further imaging confirmed the suspicion. Endoscopic sinus surgery was performed with extraction of the wooden object and evacuation of the left orbital infection.

This case indicates that intraorbital and skull base wooden foreign bodies are elusive, demanding a high index of suspicion from both clinicians and radiologists to identify retained material in the setting of ocular or sinus trauma. For better identification of wooden foreign bodies, bone windows on CT should have a width of -1000 Hounsfield units with a soft tissue window level of -500 Hounsfield units.