Optic Nerve Canal Research Articles

Endoscopic transsphenoidal resection of sellar tumors with conchal sphenoid sinus: A report of two cases.

A conchal non-pneumatized sphenoid sinus was previously considered to be a contraindication to the endoscopic transsphenoidal route to the sella due to its small sellar floor and poor anatomical landmarks, such as the optic nerve canal, opticocarotid recess and internal carotid arteries canal. The present study aimed to investigate the methodology and characteristics of the endoscopic transsphenoidal resection of sellar tumors with a conchal sphenoid sinus. Two patients with sellar tumor patients and non-pneumatized sphenoid sinuses received endoscopic transsphenoidal surgery. The two conchal sphenoid sinuses were accessed safely, total resection was achieved and no serious complications occurred. Therefore, the presence of a conchal non-pneumatized sphenoid is not an absolute contraindication for employing the endoscopic transsphenoidal route in the resection of sellar tumors; a positive outcome may be achieved, in particular when the surgery is performed by an experienced otolaryngologist.

The Pterional Port in Dual-Port Endoscopy: A 2D and 3D Cadaveric Study.

Objective We propose a novel dual-port endonasal and pterional endoscopic approach targeting midline lesions of the anterior cranial fossa with lateral extension beyond the optic nerve. Methods Ten dual-port approaches were performed on five cadaveric heads. All specimens underwent an endoscopic transtuberculum/transplanum approach followed by placement of a pterional port. The endonasal port was combined with an endoscopic extradural pterional keyhole craniectomy. The pterional port was placed at the intersection of the sphenoparietal and coronal sutures. The extradural space was explored using two-dimensional and three-dimensional endoscopes. Results The superolateral access provided by the pterional port may improve the ability to achieve a gross total resection of tumors with lateral extensions. The complete opening of the optic canal achieved through the dual-port approach may enable resection of the intracanalicular portion of a tumor, a crucial step in improvement of visual function and reduction of tumor recurrence. Conclusion The pterional port may enhance control of midline anterior skull base lesions with lateral extension beyond the optic nerve and optic canal. Dual-port endoscopy maintains minimally invasiveness and dramatically increases the working limits and control of anatomical structures well beyond what is attainable through single-port neuroendoscopy.

Compression neuropathy caused by cancer metastasis to the optic nerve canal

BackgroundCancerous cells are known to metastasize to different ocular structures. This happens especially to the choroid in males with lung cancer and females with breast cancer. However, we observed two cases of cancerous metastasis to the optic canal region. Both cases showed only a progressive decrease in vision without any other remarkable ophthalmological symptoms or abnormalities in the affected eye.Case presentationTwo females, a 60-year-old and a 73-year-old, came to our hospital because of progressive loss of vision. These patients showed no remarkable symptoms or signs in their eyes except visual acuity loss. Several ophthalmoscopic examinations, such as slit lamp microscopy and fundoscopy, showed no abnormal changes in their affected eye but magnetic resonance imaging indicated a massive legion around the optic nerve.ConclusionIt is possible for cancer to metastasize to the optic canal region and the existence of primary tumors should be considered.

Microsurgical operation for treatment of craniofacial fibrous dysplasia : report of 51 cases

Objective To investigate the diagnosis,treatment,effect and timing on the craniofacial fibrous dysplasia.Methods Retrospective analysis of 51 cases in our department from February 2002 to June 2012 for craniofacial fibrous dysplasia patients who underwent fibrous dysplasia resection,treatment of optic canal decompression in 35 cases of open,prevention of 13 cases on optic nerve decompression.Results 51 patients were followed up for 1-8 years,an average of 5.2 years,the treatment of optic nerve decompression efficiency is 88％ (31/35),prevention of decompression of optic nerve visual acuity was stable in the preoperative level,without loss of visual acuity and obvious injury.The effects of the patients were significantly changed.Conclusions The patients with craniofacial fibrous dysplasia associated with acute visual loss are suggested to underwent an immediate operation; ophthalmic artery B-mode uhrasonography can effectively evaluate prognosis after the surgery; prevention of optic nerve decompression can obtain satisfactory clinical effect. Key words: Fibrous dysplasia; Craniofacial; Optic nerve canal; Microsurgery

Surgery for traumatic optic neuropathy

Traumatic optic neuropathy (TON) is an important cause of severe visual loss following blunt or penetrating head trauma. Following the initial insult optic nerve swelling within the optic nerve canal or compression by bone fragments are thought to result in secondary retinal ganglion cell loss. Optic nerve decompression with steroids or surgical interventions or both have therefore been advocated to improve visual prognosis in TON. To examine the effects and safety of surgical interventions in the management of TON. We searched CENTRAL (which contains the Cochrane Eyes and Vision Group Trials Register) (The Cochrane Library 2013, Issue 4), Ovid MEDLINE, Ovid MEDLINE In-Process and Other Non-Indexed Citations, Ovid MEDLINE Daily, Ovid OLDMEDLINE, (January 1950 to May 2013), EMBASE (January 1980 to May 2013), Latin American and Caribbean Literature on Health Sciences (LILACS) (January 1982 to May 2013), the metaRegister of Controlled Trials (mRCT) (www.controlled-trials.com), ClinicalTrials.gov (http://clinicaltrials.gov) and the WHO International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp/search/en). We did not use any date or language restrictions in the electronic searches for trials. We last searched the electronic databases on 28 May 2013. We also searched the reference lists of other reviews and book chapters on TON. We also contacted researchers in the field. We planned to include only randomised controlled trials (RCTs) of TON in which any form of surgical intervention either on its own or in combination with steroids was compared to steroids alone or no treatment. Two authors independently assessed the titles and abstracts identified from the search strategy. No studies were found that met our inclusion criteria and therefore none were included for analysis. No studies were found that met our inclusion criteria. The current body of evidence consists mostly of small, retrospective case series. Given the wide range of surgical interventions used in TON it is very difficult to compare these studies, even qualitatively. However, there is a relatively high rate of spontaneous visual recovery and no evidence that surgical decompression of the optic nerve provides any additional benefit. On the other hand, surgery carries a definite risk of complications such as postoperative cerebrospinal fluid leak and meningitis. The decision to proceed with surgery in TON therefore remains controversial and each case needs to be assessed on its own merits. Although there is an urgent need for an adequately powered, RCT of surgical intervention in TON, this will prove a difficult endeavour.

Steroids for traumatic optic neuropathy.

Traumatic optic neuropathy (TON) is an important cause of severe visual loss following blunt or penetrating head trauma. Following the initial injury, optic nerve swelling within the optic nerve canal can result in secondary retinal ganglion cell loss. Optic nerve decompression with steroids or surgical interventions or both has therefore been advocated as a means of improving visual prognosis in TON. The aim of this review was to examine the effectiveness and safety of using steroids in TON. We searched CENTRAL (which contains the Cochrane Eyes and Vision Group Trials Register) (The Cochrane Library 2013, Issue 4), Ovid MEDLINE, Ovid MEDLINE In-Process and Other Non-Indexed Citations, Ovid MEDLINE Daily, Ovid OLDMEDLINE, (January 1950 to May 2013), EMBASE (January 1980 to May 2013), Latin American and Caribbean Literature on Health Sciences (LILACS) (January 1982 to May 2013), Web of Science Conference Proceedings Citation Index- Science (CPCI-S) (January 1990 to May 2013), the metaRegister of Controlled Trials (mRCT) (www.controlled-trials.com), ClinicalTrials.gov (http://clinicaltrials.gov) and the WHO International Clinical Trials Registry Platform (ICTRP) (www.who.int/ictrp/search/en). We did not use any date or language restrictions in the electronic searches for trials. We last searched the electronic databases on 21 May 2013. We also searched the reference lists of included studies, other reviews and book chapters on TON to find references to additional trials. The Science Citation Index was used to look for papers that cited the studies included in this review. We did not manually search any journals or conference proceedings. We contacted trial investigators and experts in the field to identify additional published and unpublished studies. We planned to include only randomised controlled trials (RCTs) of TON in which any steroid regime, either on its own or in combination with surgical optic nerve decompression, was compared to surgery alone or no treatment. Two review authors independently assessed the titles and abstracts identified from the electronic searches. We included one study that met our selection criteria; a double-masked, placebo-controlled, randomised trial of high dose intravenous steroids in patients with indirect TON diagnosed within seven days of the initial injury. A total of 31 eligible participants were randomised to receive either high dose intravenous steroids (n = 16) or placebo (n = 15), and they were all followed-up for three months. Mean final best corrected visual acuity (BCVA) was 1.78±1.23 Logarithm of the Minimum Angle of Resolution (LogMAR) in the placebo group, and 1.11±1.14 LogMAR in the steroid group. The mean difference in BCVA between the placebo and steroid groups was 0.67 LogMAR (95% confidence interval -1.54 to 0.20), and this difference was not statistically significant (P = 0.13). At three months follow-up, an improvement in BCVA of 0.40 LogMAR occurred in eight eyes (8/15, 53.3%) in the placebo group, and in 11 eyes (11/16, 68.8%) in the treatment group. This difference was not statistically significant (P = 0.38). There is a relatively high rate of spontaneous visual recovery in TON and there is no convincing data that steroids provide any additional visual benefit over observation alone. Recent evidence also suggests a possible detrimental effect of steroids in TON and further studies are urgently needed to clarify this important issue. Each case therefore needs to be assessed on an individual basis and proper informed consent is paramount.

Spheno-Orbital Meningioma Resection and Reconstruction: The Role of Piezosurgery and Premolded Titanium Mesh

We present the clinical case of a patient with a spheno-orbital meningioma. Literature review of the treatment options, including the application of piezoelectric or ultrasound surgery and orbital reconstruction after meningioma resection, is also presented. Complete resection was performed by means of a frontotemporal craniotomy and an orbitozygomatic approach. Piezoelectric osteotomy was used around the optic nerve canal and the superior orbital fissure to minimize the damage to soft tissues. Orbital wall reconstruction was done using a titanium mesh previously premolded using a skull model. The superior orbital rim was reconstructed with calvarial bone grafts, and the sphenotemporal bone defect was covered with a titanium mesh cranioplasty. Ultrasonic vibrations to perform osteotomies in craniofacial surgery provide an interesting tool to reduce damage to surrounding soft tissues. Reconstruction of the roof and lateral orbital wall with premolded titanium meshes with a skull model is a safe and easy method to achieve a good orbital reconstruction and to avoid secondary sequelae.

A perspective from magnetic resonance imaging findings of the inner ear: Relationships among cerebrospinal, ocular and inner ear fluids

Visualization of endolymphatic hydrops has been performed using magnetic resonance imaging (MRI) after intratympanic or intravenous gadolinium (Gd) injection. Our recent findings indicate that just as the prevalence of asymptomatic glaucoma is greater than that of symptomatic glaucoma, there are also many cases of asymptomatic endolymphatic hydrops. It is assumed that the asymptomatic endolymphatic hydrops that precedes Ménière's disease is found more frequently using MRI than with other techniques. Gd in the inner ear moves into the cerebrospinal fluid (CSF) via the internal auditory meatus. Gd enhancement is also recognized in the ocular fluid after the intravenous Gd administration. In this paper, the relationships between CSF, ocular fluid and inner ear fluid are reviewed. The central nervous system, eye and inner ear contain specialized extracellular fluids that are essential for maintaining their function: CSF, ocular fluid consisting of vitreous humor and aqueous humor, and inner ear fluid consisting of perilymph and endolymph. Abnormal accumulation of or pressure elevation in these fluids is associated with hydrocephalus, glaucoma and Ménière's disease, respectively. The dura mater and the arachnoid membrane of the optic nerve canal and inner ear meatus are very close to the eye and the inner ear, respectively. It has been reported that low CSF pressure is associated with glaucoma and endolymphatic hydrops. In glaucoma and Ménière's disease, nerve damage to ganglion cells rather than damage of the sensory cells is directly associated with progression of the disease. Retinal ganglion cells in glaucoma and spiral ganglion cells in Ménière's disease are targets of the abnormal accumulation of, or increased pressure in, the extracellular fluid, just as neurons are damaged in hydrocephalus. Studies on hydrocephalus, glaucoma and Ménière's disease as a group may deepen our understanding of each disease.

Anatomical landmarks for transnasal endoscopic skull base surgery

Resection of midline skull base lesions involve approaches needing extensive neurovascular manipulation. Transnasal endoscopic approach (TEA) is minimally invasive and ideal for certain selected lesions of the anterior skull base. A thorough knowledge of endonasal endoscopic anatomy is essential to be well versed with its surgical applications and this is possible only by dedicated cadaveric dissections. The goal in this study was to understand endoscopic anatomy of the orbital apex, petrous apex and the pterygopalatine fossa. Six cadaveric heads (3 injected and 3 non injected) and 12 sides, were dissected using a TEA outlining systematically, the steps of surgical dissection and the landmarks encountered. Dissection done by the "2 nostril, 4 hands" technique, allows better transnasal instrumentation with two surgeons working in unison with each other. The main surgical landmarks for the orbital apex are the carotid artery protuberance in the lateral sphenoid wall, optic nerve canal, lateral optico-carotid recess, optic strut and the V2 nerve. Orbital apex includes structures passing through the superior and inferior orbital fissure and the optic nerve canal. Vidian nerve canal and the V2 are important landmarks for the petrous apex. Identification of the sphenopalatine artery, V2 and foramen rotundum are important during dissection of the pterygopalatine fossa. In conclusion, the major potential advantage of TEA to the skull base is that it provides a direct anatomical route to the lesion without traversing any major neurovascular structures, as against the open transcranial approaches which involve more neurovascular manipulation and brain retraction. Obviously, these approaches require close cooperation and collaboration between otorhinolaryngologists and neurosurgeons.

Central corneal thickness, lamina cribrosa and peripapillary scleral histomorphometry in non-glaucomatous chinese eyes

To examine a potential correlation between a thin cornea, a thin lamina cribrosa and a thin peripapillary sclera in normal eyes of Chinese, as surrogate for a presumed association between a thin cornea and an increased glaucoma susceptibility. The histomorphometric study included 55 non-glaucomatous globes (55 patients; mean age: 41.6 ± 13.6 years) enucleated due to a malignant choroidal melanoma without involvement of the optic nerve or trabecular meshwork. The axial length ranged between 21 and 27 mm. Histological sections through the pupil and the optic disc were morphometrically evaluated. We measured the thickness of the central cornea, central and peripheral lamina cribrosa, and peripapillary sclera. The mean central corneal thickness (500 ± 68 μm) was statistically not significantly associated with the thickness of the central lamina cribrosa (207 ± 60 μm) (P = 0.62), peripheral lamina cribrosa (P = 0.61), peripapillary sclera close to the optic nerve canal (P = 0.18), peripapillary sclera just outside of the optic nerve meninges (P = 0.11), nor with the shortest distance between the prelaminar space and cerebrospinal fluid space (P = 0.09). In Chinese, central corneal thickness is not significantly correlated with the thickness of the central and peripheral lamina cribrosa and the thickness of the peripapillary sclera nor with the shortest distance between the intraocular space and the cerebrospinal fluid space. These histomorphometric data do not support a relationship between central corneal thickness and thickness of structures of the optic nerve head, and thus do not support an association between a thin cornea and increased structural glaucoma susceptibility.

A Case of Invasive Paranasal Aspergillosis with Opthalmopathy

Invasive paranasal aspergillosis has been considered to have a poor prognosis. We report a case of orbital apex syndrome due to left ethmoid-sphenoid aspergillosis. A 76-year-old woman with untreated diabetes mellitus, presented with left visual disturbance, oculomotor nerve palsy, ptosis and orbital pain. CT and MRI showed cloudy images with defects of the bone wall in the left posterior ethmoidal sinus. The serological examination revealed aspergillus antigen (+) and high levels of β-D glucan. Therefore, we diagnosed paranasal aspergillosis, and administrated voriconazol preoperatively as an antifungal agent. The patient underwent left ethmoid-sphenoidectomy and biopsy via the endonasal approach. In the histopathologic examination, aspergillus was found around the optic nerve canal. At the present, continucus administration of voriconazol has improved the patient's ptosis and orbital pain, but not her visual disturbance. This case suggests that invasive paranasal aspergillosis has the possibility of visual loss and high mortality rate so that he needs early diagnosis and treatment.

Transcranial approach for treatment for traumatic optic chiasm syndrome

To describe the visual outcome of patients with a traumatic optic chiasm syndrome, with and without neurosurgical intervention. The retrospective clinical interventional study included 14 patients, who either underwent a neurosurgical intervention with transcranial decompression of the optic canal (11 patients) in combination with a high-dosage systemic corticosteroid therapy or who received a high-dosage systemic corticosteroid treatment only (3 patients). In the surgical group, visual field improved after surgery in 6 (55%) patients and remained unchanged in 5 (45%) patients, while in none of the patients without surgery, the visual field improved. Neurosurgical decompression of the optic chiasm and optic nerve canal may be associated with a visual improvement in some patients with a traumatic optic chiasm syndrome.

Cranial-orbital approach in the treatment of optic nerve glioma

To summarize the experience in cranial-orbital approach in the treatment of optic nerve glioma. The clinical data of 35 patients with optic nerve glioma diagnosed by CT and MRI, 26 males and 9 females; aged 13 (1 - 54), with the main clinical presentations of visual defection and ex-ophthalmo and with the courses from 1 to 36 months, who underwent operation via the cranial-orbital approach 36 times, were analyzed. The diagnosis was confirmed by pathology after operation in 35 cases. Follow-up was conducted for 3 months to 8 years. Total resection was achieved in 29 cases, and subtotal resection in 6 cases. The surgical complications included temporary cerebrospinal fluid rhinorrhea (2 cases) and cataract (1 cases), and no ocular movement dysfunction was found. The follow-up rate was 77.1% (27/35). Three cases suffered from recurrence, spinal metastasis was found in 1 case, and 1 case died. resection of optic nerve glioma via cranial-orbital approach is effective. However, since residual tumor may remain in the optic nerve canal, post-operative radiation therapy is recommended.

Chronic Sphenoid Sinusitis Revisited

To assess the role of multidetector computed tomography (CT) and CT virtual sinoscopy in the evaluation of chronic sphenoid sinusitis and to compare the imaging findings with functional endoscopic sinus surgery. Prospective study. Tertiary care teaching hospital. Thirty patients with chronic sphenoid sinusitis referred for preoperative CT. Thin-section helical axial CT was performed using a multidetector CT scanner with multiplanar reformation (MPR) and volume-rendered or virtual sinoscopy images. Sixty sinuses were divided into quadrants for analysis. Extrasinus extension was labeled as the "fifth quadrant." Imaging findings were compared with those of functional endoscopic sinus surgery, and accuracy of the imaging modality was determined. Multidetector CT (axial CT and MPR) was found to be 100% sensitive, specific, and accurate in the evaluation of extent of sinusitis, status of the sinus septum, integrity of the optic nerve canal in relation to the sinus, and type of sinus pneumatization. Axial CT and MPR images showed sensitivity of 98% and specificity of 92% compared with functional endoscopic sinus surgery in evaluating the ostia. Regarding carotid canal integrity, axial CT and MPRs were 100% sensitive and 98% specific. Virtual sinoscopy showed sensitivity and specificity of 67% and 92%, respectively, for the 22 ostia that could be visualized and evaluated using this modality. Axial multidetector CT with secondary MPRs provide the necessary preoperative information regarding extent of disease and sphenoid sinus anatomy. Virtual sinoscopy is a navigational aid, an adjunct to endoscopy, and an educational tool for surgeons-in-training.

Optic Canal Decompression: A Cadaveric Study of the Effects of Surgery

To simulate a transphenoidal medial optic canal decompression and determine the anatomic effect on the optic nerve. A medial optic canal decompression was performed on 5 cadaveric optic canals within 12 hours of death. Two canals were decompressed under direct visualization and 3 were decompressed by a transphenoidal endoscopic approach. The optic canal was subsequently removed en bloc, beginning at the annulus of Zinn and extending to the optic chiasm. Each specimen was processed and examined grossly. Serial coronal step sections of the entire length of the intracanalicular optic nerve were assessed histologically. Microscopic examination of the intracanalicular portion of optic nerve revealed incision in an extraocular muscle at the annulus, incomplete bone removal, fraying of the dural sheath, incomplete dural/arachnoid release, and incision in the pia and optic nerve. Transphenoidal medial wall decompression of the optic nerve canal with dural sheath opening may induce physical damage to the nerve. Any hypothetical value in dural-arachnoid sheath opening must be weighed against the potential for harm to the optic nerve caused by the surgical intervention.

Connective Tissue Structure of the Tree Shrew Optic Nerve and Associated Ageing Changes

To identify the structure and composition of the tree shrew optic nerve to determine its potential as a model for glaucoma. Tree shrew optic nerves, aged 4 weeks to 5 years, were wax or cryoembedded for analysis of overall morphology and cellular (glial fibrillary acidic protein [GFAP]) and extracellular matrix (collagen types I, III, IV, V, VI; fibronectin; and elastin) immunolocalization studies. In addition, transmission and scanning electron microscopy were performed. In vivo optic disc imaging was performed by HRT2 and fundus camera photography. The optic nerve of the tree shrew comprised regions comparable to the human prelaminar and lamina cribrosa (LC) in the optic nerve head and the retrolaminar region, immediately posterior. The multilayered connective tissue plates of tree shrew LC stretched across the optic nerve canal at the level of the sclera and consisted of collagen types I, III, IV, V, and VI; elastin; and fibronectin. Significant age-related alterations in connective tissue components were indicated. Connective tissue was present in the central retinal vessel sheaths and was identified as longitudinally oriented collagen fibrils in the retrolaminar optic nerve. GFAP immunofluorescence indicated a high concentration of astrocytic processes in the LC. Myelination of axons was evident in the retrolaminar optic nerve. Ultrastructural studies supported the structural organization and spatial distribution of connective tissue. In contrast to many rodent models of glaucoma, since the tree shrew optic nerve resembles that in humans, especially at the LC, the tree shrew offers an ideal opportunity to investigate glaucoma pathophysiology in a subprimate model.

Treatment and visual prognosis of indirect traumatic optic neuropathy

To investigate the factors affecting visual prognosis following indirect traumatic optic neuropathy and to evaluate the effects of medication therapy (steroid mainly) and combined therapy (optic nerve decompression and medications) on the outcome of this injury. One hundred and eighty six eyes were retrospectively analyzed in this study. Multiple factors affecting visual prognosis and the comparison of result between these two different kinds of therapy were analyzed statistically. Among the 186 eyes, vision acuity was improved in 67 eyes (36.02%) and 51 eyes retrieved central vision. The ratio of vision acuity improvement was 25.74% in 136 NLP (no light perception) eyes after the injury, which was 42.26% lower than that of eyes with residual vision after the injury (P < 0.01). There was significant statistical difference in results between combined therapy and medication therapy. Logistic analysis confirmed that visual prognosis of surgery was better in the eyes with residual vision than that in NLP eyes (P < 0.01). For eyes with residual vision, optic nerve canal fracture, craniocerebral injury, old age and the delay of the first sign to show vision acuity improvement were risk factors for poor prognosis. Early surgical treatment after trauma could protect vision in indirect traumatic optic neuropathy. Post-traumatic vision was a protective factor which was linear correlated with final vision and vision improvement. NLP, coma, optic nerve canal fracture, brain injury, old age and delay of vision recovery are risk factors following indirect traumatic optic neuropathy. Therapeutic effect of optic nerve decompression combined with medication on visual acuity is better than that of medication therapy alone.

Fibrous Dysplasia of the Orbital Region: Current Clinical Perspectives in Ophthalmology and Cranio-Maxillofacial Surgery

To describe the multidisciplinary diagnosis and treatment of patients with orbital fibrous dysplasia, a slowly progressive disease that may lead to asymmetry, disfigurement, and functional ocular problems. Ten patients with orbital fibrous dysplasia underwent bifrontal craniotomy through a coronal flap, with the removal of the supraorbital arch and dysplastic process involving the anterior and middle base of the skull. Four patients underwent superior orbital fissure and optic nerve canal decompression. Reconstruction was performed by using an autologous bone graft for both the adults and children, in whom a rib graft was preferred. The mean follow-up was 53.2 +/- 18.3 months (range, 14 to 94 months). The patients' preoperative status and postoperative status were compared. The immediate and long-term morphologic and aesthetic results were good in all cases. All of the patients complained of some degree of diplopia during the immediate postoperative period, but the problem spontaneously resolved within 1 to 6 months in all but one case. No postoperative reduction in visual function was observed in the patients who underwent optic nerve decompression. The only reported complication was the irregular reabsorption of regrafted dysplastic bone in one patient. A multidisciplinary approach to orbital fibrous dysplasia is fundamental for treatment planning and execution.

高度視力障害をきたした後部副鼻腔嚢胞の４例

We reported four cases demonstrating severe visual disturbance due to mucoceles of the posterior paranasal sinuses. Two of the four patients also complained of headache and blepharoptosis or retroorbital pain. All patients were referred to our out-patient clinic by a neurosurgeon or ophthalmologist. They underwent emergency drainage surgery. We found a bony defect of the optic nerve canal in all patients. Three patients reported remarkable improvement of visual acuity postoperatively, although the optic disc in one patient appeared pale preoperatively. The remaining patient did not recover visual acuity. In that case, the optic disc was preoperatively edematous and hyperemic, and become atrophic postoperatively. There was bacteria growth found on culture of the contents of mucoceles. All patients had consulted either a local physician or ophthalmologist within two days of symptom onset. However, patients were referred to us five to 11 days (average: five days) after they initially consulted their hospital. Early diagnosis and prompt surgical management are indispensable in the treatment of severe visual disturbance due to mucoceles of the posterior paranasal sinuses.

Normal vision despite narrowing of the optic canal in fibrous dysplasia.

Fibrous dysplasia of bone frequently involves the anterior base of the cranium and results in encasement of the optic-nerve canals. It has been assumed that such encasement leads to constriction and eventual blindness. There is controversy about whether patients should be regularly monitored or whether they should undergo prophylactic decompression of the optic nerve. This question is of particular concern in patients with normal vision, since the risks associated with surgical decompression include blindness. We studied 38 patients with fibrous dysplasia of the lesser wing of the sphenoid bone. The patients underwent a detailed neuro-ophthalmologic examination and computed tomography of the face and skull, reformatted to measure the extent of involvement of the optic canal and the area of the canals. The results were compared with those of 38 age- and sex-matched controls. Of the 38 patients, 15 were male and 23 female, and their mean age was 26 years. Twelve had polyostotic fibrous dysplasia, and 26 had the McCune-Albright syndrome. Sixty-seven optic canals were affected by fibrous dysplasia; in 49 of them (73 percent) there was complete encasement. The mean (+/-SD) areas of the right and left canals were 9.6+/-3.8 mm2 and 9.9+/-3.6 mm2, respectively, in the patients, as compared with 12.0+/-2.9 mm2 and 11.9+/-2.7 mm2 in the controls (P=0.009 for the comparison of the right areas and P=0.03 for the comparison of the left areas by the paired t-test). In all but two of the patients, the results of neuro-ophthalmologic examination were normal. In the two patients with monocular visual impairment, the areas of the optic canals were similar on the normal and abnormal sides. Encasement of the optic canal in fibrous dysplasia causes narrowing of the canal, but that in itself does not result in visual loss. Therefore, prophylactic decompression of the optic nerve does not appear to be indicated on the basis of the presence of fibrous dysplasia on diagnostic images alone, since it does not correlate with visual loss.