Surgical Procedures

A standard endoscopic transnasal ethmoidectomy was carried out using a 4.0-mm, 45-degree endoscope (Karl Storz, Tuttlingen, Germany), after which the sphenoidal sinus was abundantly opened by removing its anterior wall. The optic canal and its adjacent characteristic structures, such as the anterior cranial base, orbital apex, and internal carotid artery, were identified. Then the sinus mucosa covering the optic canal was meticulously peeled off with a small sickle knife and the purple bulge visible through the medial bony wall of the optic canal was the exact location of the small lesion. Most of the medial bony wall of the optic canal from the entrance of the orbital apex to the cranial cavity was thinned using a microdrill (drill bit: diamond/15 degree/round shape in 2.9 mm diameter, integrated power console; Medtronic Inc, Fort Worth, TX, USA) and removed carefully to fully expose the tumor covered by the optic sheath. Then the optic sheath was slightly and carefully incised with a sharp #9 MVR knife about 1–2 mm away from the tumor from 4 directions (superior, inferior, anterior, posterior). After that the surgeon dissected the optic sheath covering the tumor with the small sickle knife or the #9 MVR knife while an assistant strained the optic sheath with a long thin forceps. Once the optic sheath was excised, the well-circumscribed purple encapsulated lesion, as well as the white optic nerve, was visible and the cerebrospinal fluid flowed out. The surgeon further separated the tumor from the arachnoid by blunt dissection from posterior to anterior while the assistant pulled the optic sheath medially and superiorly away from the optic nerve. During the dissection, the pupil of the operated eye was closely observed. If the pupil dilated during this procedure, which indicated possible optic nerve injury by mechanical damage or vascular compromise, any traction was released immediately and precise dissection of the tumor must be relocated. There was usually a clear demarcation of the cavernomas facilitating the separation from the optic nerve. The lesion was dissected circumferentially and removed en bloc from the optic nerve. After tumor resection, the optic nerve was clearly visible with partial absence of the optic sheath, accompanied by the cerebrospinal fluid gushing out. The final step was to reconstruct the optic nerve sheath defect with a mucoperiosteal flap, which was cut from the ipsilateral middle turbinate and deprived of bony tissue. The optic nerve sheath defect was covered by the mucoperiosteal flap with the epithelial side facing the sinus, preventing outflow of the cerebrospinal fluid. Finally, the surgical field was gently covered with 1–2 pieces of gelatin sponge soaked in dexamethasone (5 mg/2 mL) and mouse-derived nerve growth factor (30 mg/mL) (Staidson Biopharmaceuticals Co, Beijing, China) ( Figure 1 ) ( Supplemental Video available at AJO.com ).

Surgical view of removal of cavernous hemangioma of the optic canal under endoscopic transethmoidal approach. (Top left) The optic canal was exposed after opening of the sphenoid sinus. (Top right) The wall of the optic canal was thinned after being drilled and the purple bulge of tumor was exposed (black arrow). (Second row left) The periosteum of the optic canal was removed, showing a well-circumscribed tumor covered under the optic sheath (black arrow). (Second row right and Third row left) The optic sheath was incised to fully expose the encapsulated tumor (black arrow) and the nearby optic nerve (black arrowhead). (Third line right) The tumor was removed with the optic nerve intact (black arrowhead) and a defected optic sheath. (Bottom right) Tumor completely excised from the surgery. (Bottom left) The optic nerve sheath defect was reconstructed by a mucoperiosteal flap (black arrowhead).

Postoperative management included intravenous methylprednisolone (500 mg) for 3 days and intravenous broad-spectrum antibiotics for 5 days. The patients were positioned to lie in bed for 4–7 days after surgery, in a 30-degree tilt position with head up and feet down. Nose-blowing or strenuous activity was prohibited for the first 2 weeks after surgery. Because all the tumors had a clear demarcation and were removed en bloc during the surgery, the removal was believed to be complete and no further imaging examination was conducted.