Transorbital penetrating injury of the skull base and cavernous sinus - defining a minimal invasive treatment

Introduction. A transorbital intracranial injury with a foreign body can be a
 very complex and controversial therapeutic problem. The orbit's content is
 susceptible to penetrating trauma, and neurovascular skull base structures
 are at high risk from injury. There are some traditional cranial surgical
 approaches, and more recently reported different endoscopic approaches for
 treating this kind of injury. Case report. We present a case of a
 30-year-old male who had an accident at work when a piece of wood hit him in
 his head and entered through the medial aspect of his left orbit with skull
 base and cavernous sinus injury. Rapid and complete radiological and
 clinical assessments were performed, and the patient was treated in a
 minimally invasive manner. The foreign body was manually extracted with an
 endoscopic and endovascular team ready to treat adverse events. No
 postoperative complications were reported, and visual acuity increased at
 one month follow up. Conclusion. Penetrating wounds of the orbit represent a
 challenge that requires a multidisciplinary assessment and well-organized
 management. Combined endoscopic minimally invasive approaches should be
 considered during the treatment of this kind of injury.


Introduction
Transorbital penetrating injuries present a significant threat not only to orbital but also for major skull base vascular structures and cranial nerves. This type of injury represents a small portion of all head injuries; however, they make up to 24% of penetrating head injuries in adults, and 45% in children 1,2 . The penetrating injury and foreign body of the orbit can be followed by traumatic optic neuropathy presented by partial or complete loss of visual function. The extent of cerebral injury and skull base injury is related mainly to the size, shape, trajectory, and velocity of penetrating object and orbital bone anatomy.
Some injuries may be occult with a smaller foreign object and entry wound, and the foreign body itself may be composed of different materials.
Computed tomography (CT) is most frequently used to assess the head injuries, mainly because of the need for rapid diagnosis and potential metal foreign material in this kind of trauma 3,4 . The local physical, neurological, and ophthalmic examination must be performed before and after any treatment.
The treatment aims to remove the foreign body while preserving the orbital content.
Reconstruction of the skull base relationships, if required, is mandatory with as little secondary injury as possible 5 . Recovery and the functional outcome depend on many factors, the time elapsed after the injury being one of the most important 6 . The range of potential delayed intracranial complications from penetrating orbital injuries is rather broad and includes meningitis, encephalitis, pyogenic abscess, cerebrospinal fluid leakage, traumatic pseudoaneurysm, or carotid-cavernous fistula 7 . In this article, we report successful extraction of wooden foreign body from the orbit with skull base and cavernous sinus injury.

Case report
A 30-year-old male was admitted to the Emergency Department after accidental work injury when a piece of wood hit him in his head, in the region of the superior eyelid. It

Discussion
Penetrating transorbital injury always represents a complex and controversial therapeutic problem that requires a thorough patient condition assessment. Although these injuries often lead to severe consequences, and before mentioned complications can occur if appropriate surgical intervention is not performed. Traumatic optic neuropathy is one of the most important ophthalmic emergencies, and recovery success depends on the rapid treatment of optic nerve injury and decompression within 8 hours 8,9 . Standard skull and facial radiographs are not sufficient, and CT studies should include dedicated axial, coronal, and sagittal images. Fractures can be absent when the natural skull base foramina are transversed. The role of angiography is not to be underestimated before the treatment because it is essential to assess the extent of the injury and to rule out carotid dissection, traumatic pseudoaneurysm, cavernous sinus thrombosis or carotid-cavernous fistula 10 .
Some traditional and rather extensive cranial approaches to posterior orbit have been described in the literature, and in the last decade, the role of endoscopy to treat the anterior cranial fossa and skull base pathology is continuously evolving 11,12 . Our multidisciplinary team from neurosurgery, interventional neuroradiology, anesthesiology, maxillofacial surgery, and ophthalmology planned the best and most minimally invasive way to extract the foreign body 13 . There were two main solutions to this problem, and the first one is pterional craniotomy and direct microsurgical control of the cavernous sinus and potential carotid injury during extraction. The second one, manual extraction itself and, if needed, and subsequent endoscopic examination with local tamponade of the wound. Angio suite was prepared for fast access and endovascular carotid control in case of uncontrolled bleeding during an actual treatment 14,15 . The endoscope inserted through the wound or additional surgical incision offers good exposure of the orbit and all anterior skull base region, with the possibility of angled vision to important neurovascular structures 16 .

Conclusion
Surgical removal of penetrating orbital foreign bodies is a classic example of an interdisciplinary therapeutic approach, where the best outcome is usually the result of rapid intervention and assessing the best approach. Combined endoscopic minimally invasive approaches should be considered during the treatment of this kind of injury.   Accepted October 2, 2020.