Feasibility of navigation-assisted endoscopic transnasal optic nerve decompression for the treatment of traumatic optic neuropathy in patients with midfacial fractures

Abstract

Objectives: Traumatic optic neuropathy (TON), a relatively rare condition, can cause visual functional impairment and permanent functional damage. Surgeons should be familiar with its diagnostic criteria and treatment to effectively manage cases of facial trauma with TON. We investigated the feasibility of navigation-assisted endoscopic trans-nasal optic nerve decompression (ETOND) to treat TON in maxillofacial trauma patients. Patients and.

Methods: We retrospectively analyzed data from the clinical investigation of four consecutive patients, two males and two females with an average age of 75 years, with midfacial fractures and TON between April 2021 and September 2023. All patients had swelling and subcutaneous periorbital hemorrhage accompanied by optic nerve canal and zygomaticomaxillary complex fractures on the affected side. Three patients had lacerations on the lateral eyebrow or upper eyelid. All patients were evaluated by an ophthalmologist for visual impairment; two patients could see hand motion at a 30 cm distance, one patient could perceive light, and one did not have any loss of visual acuity. Among the four patients, three had visual impairment immediately after the injury, and one showed delayed impairment.

Results: The patients were treated with navigation-assisted ETOND conducted by an endoscopic rhinologist. Three of the ETONDs were performed along with open reduction and internal fixation (ORIF); the other ETOND was delayed. Orbital reconstruction was performed in three patients. Steroid therapy was administered to two patients, one pre-operatively and one post-operatively. The two patients with pre-operative vision loss showed improved visual acuity post-operatively, and the two patients with no pre-operative visual impairment had no vision loss associated with ORIF for their midfacial fractures. No patient had post-operative complications.

Conclusion: Navigation-assisted ETOND can be performed easily by endoscopic rhinologists; and prompt examination, diagnosis, and treatment are important in patients with facial trauma and TON.

Keywords: Midfacial fracture; Navigation-assisted endoscopic trans-nasal optic nerve decompression; Optic nerve canal fracture; Traumatic optic neuropathy.

Fig. 1

The anatomical relationships among the structures surrounding the optic nerve.

Fig. 2

Pre-operative computed tomography (CT) findings of Patient #1. A, B. Axial and coronal CT images showing a fracture of the lateral wall of the left optic nerve canal. The bone fragment compresses the left optic nerve within the nerve canal (yellow arrows). C, D. Coronal and three-dimensional CT images showing naso-orbito-ethmoid type I fracture, left zygomaticomaxillary complex fracture, and inferior wall fracture of the left orbit (yellow arrow).

Fig. 3

Surgical view of Patient #1. A. During navigation-assisted endoscopic trans-nasal optic nerve decompression performed by an endoscopic rhinologist, a depressed bone fragment was identified in the distal part of the optic canal. B. Depressed bone fragments were filed. C. Decompression of the optic nerve canal was performed. The optic nerve sheath (white arrow) was visualized after bone removal. D. open reduction and internal fixation (ORIF) of midfacial fractures; the left zygomaticomaxillary complex fractures were treated by ORIF with a hemi-coronal incision approach. E. Bone was harvested from the anterior wall of the maxillary sinus. F. The harvested bone was shaped according to the morphology of the left orbital floor. G. The orbital floor was reconstructed using the harvested bone and fixed with micro-titanium screws.

Fig. 4

Post-operative computed tomography (CT) findings of Patient #1. A. Axial CT showing removal and release of the bone fragments around the optic nerve canal (yellow arrow). B-D. Three-dimensional CT shows that the midfacial fracture, including orbital morphology, was adequately reconstructed (yellow arrows).

Fig. 5

Computed tomography (CT) findings and surgical view of Patient #2. A, B. Axial and coronal pre-operative CT showing a fracture of the lateral wall of the left optic nerve canal. A bone fragment was compressing the left optic nerve within the nerve canal (yellow arrows). C, D. Axial and three-dimensional pre-operative CT showing a left zygomaticomaxillary complex fracture with medial displacement of bone fragments. E. During navigation-assisted endoscopic trans-nasal optic nerve decompression performed by an endoscopic rhinologist, a depressed bone fragment was identified in the distal part of the optic nerve canal. F. Bone fragment removal. G, H. Axial and coronal post-operative CT showing the removal and release of the bone fragments around the optic nerve canal (yellow arrows). I. Three-dimensional post-operative CT shows that the zygomatic fragment was repositioned symmetrically.

Fig. 6

Pre-operative computed tomography (CT) findings of Patient #3. A. Axial CT showing a fracture of the frontal bone. B. Axial CT showing a fracture of the left zygomaticomaxillary complex. C, D. Coronal and axial CT showing a left type IV blowout fracture, medial orbital wall fracture, and optic nerve canal fracture (yellow arrow). E. Three-dimensional CT showing fracture of the frontal bone, a type I left naso-orbito-ethmoid fracture, and a left zygomaticomaxillary complex fracture.

Fig. 7

Surgical view of Patient #3. A. ORIF of the midfacial fractures, frontal bone fracture, and left zygomaticomaxillary complex fracture were treated by ORIF with a bi-coronal incision. B. The zygomaticomaxillary buttress and the nasomaxillary buttress were treated by ORIF through an oral vestibular incision. C. The infraorbital rim was treated by ORIF through a sub-tarsal incision. D. The bone used for orbital floor reconstruction was harvested from the parietal exostosis. E. Workflow based on intra-operative CT to update the navigation system and navigation-assisted ETOND and intra-operative CT imaging using mobile-type cone-beam CT (3D Accuitomo M, Morita). F. Registration of the navigation system (Stealth Station ENT) using intraoperatively acquired CT data. G. Screen view during registration to the navigation system. H. Navigation-assisted ETOND by an endoscopic rhinologist. I. During the navigation-assisted ETOND performed by the endoscopic rhinologist, the posterior wall of the posterior ethmoid sinus was removed to gain access to the sphenoid sinuses (black arrows). J. Optic prominence (white arrow) with a view of the sphenoid sinus. (ORIF: open reduction and internal fixation, CT: computed tomography, ETOND: endoscopic trans-nasal optic nerve decompression)

Fig. 8

Post-operative computed tomography (CT) findings of Patient #3. A, B. Three-dimensional construction and coronal CT showing that the midfacial fracture, including orbital morphology, were adequately reconstructed. C. Axial CT showing release of the bone on the medial side of the optic nerve canal (yellow arrow).