Transcranial optic canal stenosis decompression

Skull dysplasia, osteopetrosis or marble bone and anterior cranial fossa fractures involving the optic canal and other optic nerves produce visual impairment. Transcranial decompression is often used. Improve vision. Curing disease: Indication (1) The fibrous structure of the cranial sac is poor, involving one or both optic canal, leading to narrowing of the optic canal, compression of the optic nerve, and visual loss. (2) Patients with osteopetrosis, with loss of vision on one side or both sides, and the optic nerve hole was taken to confirm the stenosis. (3) The anterior cranial fossa fracture involves the optic canal, and the fracture piece compresses the optic nerve, vision loss or progressive visual deterioration. Contraindications (1) optic canal stenosis oppresses the optic nerve, resulting in complete loss of vision for more than 1 month. (2) Optic canal fracture, complete loss of visual acuity after injury. Surgical procedure (1) scalp incision: bilateral coronal incision in the forehead of the forehead is generally used. If a transsphenoidal approach is used, the forehead flap incision is performed. (2) Bone craniotomy: one side of the optic canal decompression, using the affected side of the forehead bone flap. When the bilateral optic canal decompression was completed once, the bilateral forehead bone flap was used. When the pterional approach is used, the frontal iliac bone flap is used. (3) Dural incision: In order to accurately determine the position of the optic canal and remove the upper part of the optic canal from the intracranial end to the inner end of the ankle, a combination of intradural and epidural operations is generally used. First, the dura mater is cut, and the frontal lobe is retracted along the frontal lobe by the cerebral pressure plate to find the intracranial segment of the optic nerve and the proximal or intracranial end of the optic canal. Then, the optic nerve was cut along the optic nerve to cut the dura mater 3 cm, and the dura mater and the tarsal plate were peeled off from the epidural space to open the upper wall of the optic canal or "unroofing" and Cut off the thickened upper wall to prepare. (4) optic canal decompression: resection of the optic canal in the upper half of the oppressive bone, the surgeon must be very careful and meticulous, the operation should be accurate, gentle, and can not be a slight mistake. Therefore, it is best to operate under a surgical microscope. The upper wall of the optic canal is thinned using a high-speed micro drill. It should be pointed out that in the treatment of patients with poor bone fiber structure and osteopetrosis, the former part of the optic canal has thickening and deformation; the latter has sclerosing changes. Be patient when you remove the optic canal bone. You can't rush to make it, but to remove it little by little until there is only a thin layer of bone on the upper wall of the optic canal. Then, the microscopic stripper is gently separated between the optic nerve sheath and the inner wall of the optic canal, and the upper wall of the optic canal is completely removed by a curette or an ultra-thin Kerrison rongeur, that is, "topping". However, traumatic optic nerve injury is often accompanied by hemorrhage and edema, so the optic nerve sheath can be cut during surgery to make the decompression sufficient. For patients with poor fibrous structure of the skull or osteochondral stenosis, only the upper wall of the optic nerve is removed. Decompression of the optic nerve is not enough. The inner and outer sidewalls of the optic canal should be removed by micro-drilling to reach the upper half of the optic canal (180°). The bone hemorrhage is filled with bone wax. The optic nerve sheath generally does not need to be cut open to avoid an increase in optic nerve damage. Patients with osteopetrosis often have bilateral stenosis of the optic canal, resulting in decreased vision in both eyes. Due to the bone sclerosing change of this disease, the optic nerve is squeezed by the hardened and narrowed bone tube. The decompression of the optic nerve is more difficult to operate than the optic canal compression caused by the optic canal fracture and the poor fibrous structure of the skull. Must be more meticulous and patient. According to Haines, many patients still have improved vision after surgery. In addition, because the disease is mostly bilateral optic canal stenosis, bilateral decompression can be completed in one operation, and can also be carried out in stages. (5) upper wall resection: patients with poor fibrous structure of the skull, upper wall of the iliac crest and thickened sphenoid humerus, often accompanied by pressure on the external process of the eyeball and supracondylar fissure, eye movement motor paralysis. At this time, the thickened bone of the upper wall and the sphenoid ridge should also be removed for total decompression. (6) Guan skull: sutured dura mater, cranial valve reduction, external drainage of the dura mater, sutured periosteum, cap aponeurosis and skin. complication (1) Postoperative visual acuity decline: related to intraoperative operation touching the optic nerve, and more can gradually recover. (2) Cerebrospinal fluid rhinorrhea: the frontal sinus or ethmoid sinus is opened during the operation of the bone flap or the thickened bone is removed, and the intraoperative repair is not done. If it can not be cured after a few weeks of conservative treatment or relapse after self-healing, it needs to be repaired again.