Blunt contusion of the eye is the most common form of mechanical closed ocular trauma, with the most significant damage being optic nerve contusion, which can be combined with optic nerve injury in approximately 10% of patients after cranial, facial, and ocular injuries. Optic nerve injuries are often associated with anterior and middle cranial fossa fractures involving the orbital apex and optic canal. When the optic nerve is contused, vision loss or even blindness occurs, with loss of direct light reflexes and normal indirect light reflexes. If the optic cross section is damaged, there is impaired vision in both eyes and visual field defects.
Diagnosis
Optic nerve injury site.
1, optic nerve injury in the neural tube area, mostly seen in traumatic optic neuropathy.
2, the junction between the eye and the optic nerve, mostly seen in optic nerve avulsion injuries.
3, intraorbital and intracanalicular optic nerve segments. Mainly due to direct injury, primary damage: including shear contusion of the optic nerve canal opening and cranial opening, contusion of the optic nerve by local fracture displacement; secondary damage: including compression of the optic nerve by fracture and bone displacement, compression by hemorrhage and edema in the optic nerve canal after contusion, and increased intrathecal pressure due to hemorrhage and edema in the nerve sheath.
(1) X-rays cephalographs, skull base tomography, CT scans Inferring cerebral nerve injury by fracture line course.
(2) MRI skull base thin section scan occasionally reveals swelling, hemorrhage, and fracture of the nerve root.
(3) Electrophysiological examination of evoked potentials can detect the degree of optic nerve injury.
Treatment methods
1, the optic nerve is sensitive to compression, ischemia and hypoxia and its sensitivity, so it should be treated as an emergency emergency.
Treatment measures.
(1) Give immediate treatment with a rapid intravenous drip of 250 ml of mannitol for dehydration, followed by methylprednisolone 500 mg intravenously. The maintenance amount of mannitol dehydration is 100~150 ml every 8 hours for 2~3 days; methylprednisolone 500 mg IV can be repeated after 6~8 hours, usually for no more than 48 hours.
(2) Complete the necessary auxiliary examinations as soon as possible: CT examination of the orbit and optic nerve canal should be completed within 2 h; visual electrophysiological examination within 12 h; MRI examination should be completed within 24 h. Based on the above, determine whether surgical optic canal decompression treatment is required.
(3) Surgical treatment: Hopefully within 24~48h. It includes frontal diameter craniotomy, endoscopic pterygoid sieve approach, and intraorbital wall approach, etc.
2.Non-surgical treatment is the main treatment
Non-surgical treatment.
(1) Dehydration drugs to relieve intracranial pressure and neuroedema. Commonly used 20% mannitol 150-200ml intravenous drip, 1~2 times a day.
(2) Glucocorticoid therapy to protect the nerves, commonly used dexamethasone 10mg intravenous drip, 1 to 2 times a day.
(3) Vasodilation and improvement of microcirculation. Take Yunnan Baiyao capsule and Diosmin orally. Low molecular dextran 500ml intravenous drip, 1 to 2 times a day.
(4) Neurotrophic and metabolic drugs commonly used are energy synergist, brain activator, GM1, murine nerve growth factor and micarb. Micobal is administered intravenously 500μg once or twice a day, then orally 0.5mg 3 times a day after 10 days.
Surgical treatment.
(1) Indications for surgery: ① Fracture fragments compressing the cerebral nerve. (2) Persistent increase in intracranial pressure and compression of cerebral nerve. (3) Non-surgical treatment is ineffective. (4) Causes late severe neurological irritation such as vertigo and neuralgia.
(2) Preoperative preparation: identify the nerve injury site by imaging, electrophysiology and clinical manifestations; select the nerve muscle for transplantation.
(3) Surgical procedures: (1) neurological decompression, which is performed via intracranial or extracranial approach, using an abrasive drill to remove the bone fragments compressing the nerve, remove the perineural hematoma, and microscopically incise the epineural membrane, such as decompression of the optic nerve canal and facial nerve canal; (2) nerve reconstruction, including direct reconstruction, such as direct anastomosis of nerve severed ends and nerve graft anastomosis.
Postoperative management: comprehensive recovery with drugs, physiotherapy and acupuncture.