Intraorbital bamboo foreign body is extremely rare. A Pubmed-based search indicated that there have been only two cases reported. (11,12) In previous cases, they are both small pieces of bamboo. Different with them, this is the unique case of a missed large hollow bamboo traversing the orbit and infratemporal fossa with minimal sequelae. In Southeast China, bamboo is more productive than other areas. It is widely used in many works. So it is familiar that a patient injured by bamboo in work-related accidents at our hospital emergency department. However, almost all of them involved extremities. In orbital injury, our case is very rare.
Intraocular foreign body is easily misdiagnosed, even if in some patients with external wound. (13) Patients with intraorbital foreign bodies may not notice the presence of the object and may not remember the details of their injury at their initial visit. (14) In our case, due to the patient denied the significant trauma in orbit, the initial doctor he visited overlooked the possibility of intraorbital foreign bodies. Similar with our patient, one previously reported case with the intraorbital bamboo object was also misdiagnosed by the first clinic he visited and 10 month later the foreign body in the orbit was detected. (12)
Unlike metallic object, bamboo or wood has porous consistency and organic nature which provides a good medium for microbial agents. (12) Complications, such as panophthalmitis, periorbital abscess, and fistula formation, can be caused by organic foreign bodies. (15) So it is important to detect and remove such foreign bodies. However, detection of an intraorbital bamboo or wooden material may be difficult.
CT is the best choice for detecting most foreign bodies. (16) Bamboo or wooden foreign bodies have the similar density of soft tissue or fat. (17,18) And bamboo is considered to be more compact than wood and is isodensity with fat in acute phase. (11) Hence, in the acute stage, they are easy to be misinterpreted as air bubbles on CT. (11) In the chronic stage, dry object may become wet object, resulting in dramatic increases. (11) And such foreign bodies are reportedly denser than soft tissue. (12,19) In present case, CT scan was performed 14 hours after trauma and the density of the intraorbital object is similar with that of the orbital fat. Because the object is relatively large, it is easy to be detected by CT scan. In two previous cases, one was underwent CT scan within a day of the accident and the foreign bamboo object was isodense with the orbital fat. Since the left medial rectus muscle was penetrated by a linear structure, a foreign body was identified. (11) The other one was performed CT scan 10 months after facial trauma and CT showed that the object was sightly denser than extraocular muscles. (12) Shelsta et al reviewed clinical characteristics of 23 patients with wooden intraorbital foreign body and found that the radiologist could not make a definitive diagnosis of orbital foreign body in 35% of subjects at the time of presentation. (19) In another study, Dalley indicated that bone windows are more effective in identifying acute intraorbital wood foreign bodies than soft tissue windows. (20) Therefore, it is important that communication with the radiologist before examination and to ask for adjust settings. (19) Magnetic resonance imaging (MRI) may be superior to CT in identifying such foreign bodies. (18,21) While other study demonstrated that MRI is not superior to CT in the evaluation of a bamboo or wooden object in the orbit. (15) However, in most hospitals, CT scan is still the first choice.
Once the diagnosis of an intraorbital foreign body is confirmed, it should be removed in time. Especially the foreign body is an organic material, such as bamboo, which may induce severe complications. It has been indicated that early detection and removal of foreign bodies is associated with better prognosis. (22) In our case, the intraorbital object was removed within a day of the trauma and no obvious necrosis tissues and purulent exudate was found. In two previously reported cases, one was also performed emergency surgery within 24 hours of the accident. (11) But the other one was diagnosed 10 months after the trauma and a surrounding purulent abscess was found in operation. (12) Although the foreign body was large and traversed the infratemporal fossa in our case, it was removed easily without injuring surrounding structures. Since the foreign object is large which is easy to be found and the surface of the hollow bamboo is smooth which makes it move easily.
In summary, we report an unique case of a missed large hollow bamboo traversing the orbit and infratemporal fossa with minimal sequelae. A bamboo foreign body in orbit is extremely rare and is easily misdiagnosed. The physician during the initial evaluation of eye trauma patients should take the history and physical examination extraordinarily carefully, and a CT or MRI scan may be recommended to prevent missing such foreign bodies in orbit. Once the diagnosis of such orbital foreign body is established, the object should be removed in time.