Removal of intraconal bullet through endoscopic transnasal surgery with image-guided navigation system 8 months after injury: a case report
Lodgment of a bullet within the orbit is uncommon. The decision to remove these objects poses a challenge to surgeons due to a high risk of complications. Currently, endoscopic transnasal surgery with navigator assistance facilitates the localization of foreign bodies allowing their safe removal with minimal surrounding tissue damage or optic nerve injury.
We describe a case of a 26-year-old Thai woman with a chronic intraorbital foreign body located within her medial intraconal space. The chronic intraorbital foreign body was successfully removed by endoscopic transnasal surgery, combined with assistance from a navigation system, 8 months after injury without any damage to her eye or disturbance in vision.
Intraconal foreign bodies, such as bullets, are a chronic problem and should be observed in the long term; prompt surgical removal should be performed if indicated.
KeywordsBullet Transnasal endoscopic approach Navigator-assistance Orbit Case report
Bullet injuries to the face are uncommon. They are dangerous due to the complexity of craniofacial anatomy and the presence of vital structures. The retrieval of intraorbital foreign bodies is technically difficult and challenging. Classically, external approaches have been the most widely used; however, these are invasive and associated with several major disadvantages, such as postsurgical scarring and considerable morbidity . Recently, improvement in technology and our understanding of anatomy have gradually progressed to enable minimally invasive procedures, such as endoscopic surgery. Endoscopic surgery has the advantage of gaining access, transnasally, into the medial intraconal space with minimal surrounding tissue damage and with no unsightly external scars . This case report presents a case of a 26-year-old woman who had an accidental gunshot injury in which the bullet was retained in her left eye; the gunshot injury developed into eye pain 8 months after the injury. Fortunately, the bullet was successfully removed via a transnasal endoscopic approach with the aid of an image-guided navigation system, without any morbidity.
Gunshot injuries to the craniofacial region are uncommon but can cause loss of life or irreversible damage to vital organs. The bullet may traverse in any direction and/or lodge in any site of the craniofacial region; the commonest site of lodgment of facial foreign bodies is the paranasal sinuses [3, 4, 5, 6]. It is rare for a bullet to be lodged in the orbital cavity without causing much damage to the orbital structure, as seen in the present case. From an anatomic point of view, the orbit is a highly complex area which is divided into two compartments by the extraocular muscles: intraconal and extraconal . Traumatic intraocular foreign body injury can be associated with partial or complete loss of visual function. A tiny foreign body retained within the orbit can cause either immediate or delayed complications, including chronic orbital inflammation, osteomyelitis, thrombotic vasculitis, or diffuse infections from septicopyemia. Although these injuries often lead to serious consequences, in some cases they may have a good long-term prognosis. A chart review study of 43 patients with metallic orbital foreign bodies that were retained from 6 months to 63 years (median, 2 years) found that they were generally well tolerated , as with our patient who did not have any symptom until 8 months later.
Optic nerve injury results in both mechanical and ischemic damage. Walsh divided this damage into primary or secondary mechanisms . Primary mechanisms result in permanent injury to the optic nerve axons at the moment of impact. Secondary mechanisms include vasospasm and swelling of the optic nerve, within the boundaries of the optic canal, leading to the worsening of ischemia and further loss of axons in the period following the trauma .
Radiology studies are important initial tests; plain radiology is helpful to confirm diagnosis and localize the foreign body. However, a CT scan helps pinpoint the exact location of the bullet; hence, providing a roadmap for safe and precise removal. Although magnetic resonance imaging (MRI) provides very detailed soft tissue architecture, it is contraindicated in cases of metallic foreign bodies because of the potential risk for migration and further injury.
Indications for surgical removal in patients with intraorbital foreign bodies
Palpable orbital mass
Signs of orbital infection or inflammation
Orbital symptoms: pain, proptosis, decreased visual acuity, and restricted mobility
Optic nerve compression
Large or sharp-edged foreign body
Suspicion of inorganic foreign bodies or copper materials
The surgical approach, for removal, depends on the nature of the body, its location (anterior or posterior orbit), and associated complications (infections, optic nerve lesions or compression, and lesions to the extraocular nerve or intraorbital blood vessels) . Conventional open methods of removal increase morbidity, scarring, disfigurement, and other complications. Transnasal endoscopic removal is safe, less damaging, and easy because it gives you direct visualization. Endoscopic removal of a bullet from the orbit has been reported in the literature [13, 14, 15]. Furthermore, the navigation system has been shown to be an essential element, working in combination with endoscopic intervention, for precise location of the target, thereby enabling surgeons to make the smallest possible opening in the bone and periorbita [16, 17]; so, transnasal endoscopic surgery is becoming increasingly popular as a safe surgical technique to access the medial intraconal space.
In the present case, the bullet was removed via a transnasal endoscopic approach through anterior and posterior ethmoid sinus from the intraconal area. This approach is minimally invasive and recommended in cases of foreign bodies, especially in the midline craniofacial region, in combination with an image-guided navigator system, which greatly enhances the chances of surgical success with minimal ocular complications.
Intraconal foreign bodies, such as a bullet, are a chronic problem and should be observed in the long term, so as to perform prompt surgical removal if indicated. Endoscopic transnasal surgery, with navigation system assistance, is a safer and less invasive approach than classic surgical techniques. Currently, a navigation-assisted surgery system has been shown to be an essential element in endoscopic intervention, which facilitates a trend in endoscopic intervention becoming more available.
The authors wish to thank the Faculty of Medicine, Prince of Songkla University for funded support.
The research was supported by a grant from the Faculty of Medicine, Prince of Songkla University, Thailand.
Availability of data and materials
Database of Faculty of Medicine, Prince of Songkla University.
CP was a major contributor in writing the case report. UP drafted the manuscript and designed the figures. Both authors read and approved the final manuscript.
Ethics approval and consent to participate
The Ethic Committee at Faculty of Medicine, Prince of Songkla University approved the study protocol. The reference number of the study approval was EC61-276-13-1. All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki Declaration and its later amendments or comparable ethical standards.
Consent for publication
Written informed consent was obtained from the patient for publication of this case report along with any accompanying images. A copy of the written consent is available for review by the Editor-in-Chief of this journal.
The authors declare that they have no competing interests.
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