[Theoretic explanation about visual disorder induced by fibrous dysplasia of skull: pressure disequilibrium between lamina cribrosa].

OBJECTIVE: To investigate the causes for changes in optic nerve head and visual impairment caused by fibrous dysplasia (FD) of optic canal stenosis. METHODS: A total of 12 FD patients, diagnosed by CT, received the fundus and optical coherence tomography (OCT). Those with FD involving optic canal underwent decompression. The examination of OCT showed that lamina cribrosa located at the top was the exposure factor for retinal pigment epithelium (RPE). There were decreased vision or edematous optic nerve and atrophic lesion. Odds ratio was calculated by Fisher's exact test. RESULTS: The examination of CT showed the results of optic canal stenosis caused by lesions involving 18 sides: 8-sides with normal vision. Among which, 6 showing that lamina cribrosa was located below RPE and a lamina cribrosa plate near RPE at follow-up, 1 side OCT showing lamina cribrosa above RPE with normal optic nerve; a lateral lamina cribrosa was located above RPE with edematous optic nerve. Visual impairment at 10 sides, normal papillary 2 sides, atrophic papillary 8 sides, OCT showed that lamina cribrosa was located above RPE, postoperatively OCT showed that lamina cribrosa below with 7 sides having improved visual acuity. Fisher's exact test was performed (P = 0.000, odds ratio = infinity). CONCLUSION: The optic canal stenosis causes a rising pressure of lamina cribrosa zone to shift above RPE. The channel becomes distorted so as to squeeze and cut the ganglion cell axons of optic nerve, block the axoplasmic transport and result in blood circulation disorder. The above factors are the etiologies of visual impairments. Postoperatively lamina cribrosa zone pressure drops so that depressed lamina cribrosa and channel deformation recover and visual acuity improves.

[Neurosurgical therapy of transorbital intracranial foreign bodies: review of 28 cases].

OBJECTIVE: To discuss the benefits and complications of the neurosurgical therapy in transorbital intracranial foreign bodies. METHODS: The clinical data of 28 cases of transorbital intracranial foreign bodies, metallic in 13 cases, vegetal 5 cases, and vitreous, plastic and other kinds in 10 cases, were analyzed retrospectively. Optic nerve injury was found in 13 cases, orbital apex syndrome in 11 cases; CSF rhinorrhea in 13 cases, CSF orbital leak in 3 cases, and hemiplegia in 2 cases. All the patients underwent head CT scan, and orbital horizontal and coronal CT scan. The patients with metallic foreign bodies had DSA exams, and the non-metallic cases had MRA scans. 22 cases had orbital-frontal craniotomy and foreign body resection, and 6 cases had direct foreign body extraction. All the cases received antibiotic and nerve nutritional therapy postoperatively. RESULT: The cases in which the foreign bodies came from the orbital roof into the skull recovered well postoperatively; and the cases in which the foreign bodies came from the superior orbital fissure into the skull showed hemiplegia (n = 2) or orbital apex syndrome (n = 6) postoperatively. CONCLUSION: Transorbital intracranial foreign body should be diagnosed in early stage to avoid missed diagnosis. Omission should be avoided during resection of the foreign body. The relationship between the foreign body and internal carotid artery should be examined carefully before the extraction. Direct extraction of foreign body causes less injury, and patients' condition should be followed up.

[Trans-cranio-naso-orbital approach in treatment of ethmoid sinus malignant tumors: analysis of 39 cases].

OBJECTIVE: To summarize the experience in treatment of ethmoid sinus malignant tumors via trans-cranio-naso-orbital approach. Post-operationally follow-up was conducted in 27 cases for 3.5 years (3 months to 7 years). METHODS: The clinical data of 39 patients with ethmoid sinus malignant tumors, 25 males and 14 females, aged 42 (20 - 65), with the chief complaints of nasal airway obstruction, rhinorrhagia, nasal neoplasm, exophthalmos, decreased vision, facial numbness, disturbance of consciousness, etc, who underwent resection of tumor via trans-cranio-naso-orbital approach retrospectively. Pre-operational MR showed that the tumor invaded the anterior cranial fossa in 38 cases, invading the orbit in 31 cases, invaded the pterygopalatine fossa in 5 cases, invaded the middle cranial fossa and cavernous sinus in 3 cases. RESULTS: Tumor total removal was achieved in 32 cases (including removal en bloc in 9 cases), and subtotal removal in 7 cases. Pathological examination diagnosed 10 cases as with olfactory neuroblastoma, 8 cases with adenocarcinoma, 7 cases with squamous cell carcinoma, 6 cases with pallima carcinoma, 4 cases with unclassified sarcoma, 3 cases with undifferentiated carcinoma, and 1 case with schneiderian carcinoma. Postoperatively, temporal CSF leak was found in 5 cases. There was no intracranial or wound infection. Local recurrence was found in 8 cases, 1 case had lung metastasis, and 4 cases died 1 month to 6 years postoperatively. CONCLUSION: Adequate exposure of the ethmoid sinus tumor involving the anterior cranial fossa and orbit can be obtained via suitable trans-cranio-naso-orbital approach, and by this approach the tumor can be removed en bloc. This approach is relatively safe and with few complications.

[Transcranial optic nerve decompression for optic nerve injury].

OBJECTIVE: To discuss the operative indications and advantages of transcranial optic nerve decompression in treatment of optic nerve injury resulted from skull base fracture. METHODS: The data, such as the site of impact, vision, ocular movement, characteristic of CT, and pathologic changes during operation, and the extent of operative decompression of 118 patients with optic nerve injury. According the site of impact on the head, 87 of lateral superciliary arch type, 18 of medial superciliary arch type, and 13 of zygomatic type, undergoing transcranial optic nerve decompression were analyzed retrospectively. The patients were followed up for 6 months after operation. For the purpose of evaluation, the postoperative outcome of visual acuity was classified into five grades: blindness, hand movement, finger count, light perception and visual acuity > 0.05. The visual acuity improvement reaching one grade or more was defined as effective. The improvement of visual field was also considered effective. RESULTS: After follow-up of 6 months, effect was shown in 35 out of the 72 patients with pre-operative blindness (48.6%), and all the 46 patients with residual vision (100%). The total effective rate was 68.6%. The post-operative effective rate was 64.4% in patients with lateral superciliary arch type, 83.3% in patients with medial superciliary arch type injury and 76.9% in patients with zygomatic type injury. CONCLUSIONS: Transcranial optic nerve decompression is worthy recommending to the patients with traumatic optic neuropathy. The operative indications include patients with residual vision; patients with bilateral optic nerve injury; and patients with blindness less than 3 days.

[Surgical treatment of fibrous dysplasia of the skull with neuro-navagation].

OBJECTIVE: To evaluate the role and effect of neuro-navagation in the surgical treatment of fibrous dysplasia of the skull and to discuss the indication and advantages of transcranial optic nerve decompression are discussed. METHODS: Fifteen patients with fibrous dysplasia of skull, 6 males and 9 females, aged 10.3 (5 approximately 21), were surgically treated by transcranial approach. The location of lesion, symptoms and signs, CT characteristics, surgical approaches, and outcomes were analyzed. The postoperative outcomes of visual acuity were grouped into 5 categories: blindness, light perception, hand motion, counting fingers, and recognizing acuity chart. Improvement of visual acuity of one grade or more or increase of 0.1 by acuity chart, and improvement of visual field were defined as effective. RESULTS: Fibrous dysplasia of skull in children most often involved the frontal, sphenoid, and ethmoid bones and resulted in stenosis of optic canal and superior optic fissure. The most common symptoms were decreased vision, proptosis and facial asymmetry. 13 patients underwent decompression of optic canal in lateral side, and two patients in both side. All the cases had pathological diagnosis of Fibrous dysplasia of the skull. After 3-to-25-month follow-up, improvement was found in 11 eyes (65%), and no improvement was found in 6 eyes (35%). Decreased vision was not seen. CONCLUSION: Transcranial optic nerve decompression is an effective treatment for decreased vision induced by Fibrous dysplasia of the skull.