Anterolateral keyhole transorbital routes to the skull base: a comparative anatomical study.

OBJECTIVE: Although keyhole transorbital approaches are gaining traction, their indications have not been adequately studied comparatively. In this study the authors have defined them also as transwing approaches-meaning that they use the different facies of the sphenoid wing for cranial entry-and sought to compare the four major ones: 1) lateral orbitocraniotomy through a lateral canthal incision (LatOrb); 2) modified orbitozygomatic approach through a palpebral incision (ModOzPalp); 3) modified orbitozygomatic approach through an eyebrow incision (ModOzEyB); and 4) supraorbital craniotomy through an eyebrow incision (SupraOrb), coupled with its expanded version (SupraTransOrb). METHODS: Cadaveric dissections were performed at the neuroanatomy lab. To delineate the skull base exposure, four formalin-fixed heads were used, with two sides dedicated to each approach. The outer limits were assessed via image guidance and were mapped and illustrated accordingly. A fifth head was dissected purely endoscopically, just to facilitate an overview of the transwing concept. Qualitative features were also rigorously examined. RESULTS: The LatOrb proves to be more versatile in the middle cranial fossa (MCF), whereas the anterior cranial fossa (ACF) exposure is limited to a small area above the sphenoid ridge. An anterior clinoidectomy is possible; however, the exposure of the roof of the optic canal is suboptimal. The ModOzPalp adequately exposes both the ACF and MCF. Its lateral trajectory allows the inferior to superior view, yet there is restricted access to the medial anterior skull base (olfactory groove). The ModOzEyB also provides extensive exposure of the ACF and MCF, but has a more superior to inferior trajectory compared to the ModOzPalp, making it more appropriate for pathology reaching the medial anterior skull base or even the contralateral side. The anterior clinoidectomy is performed with improved visualization of the optic canal. The SupraOrb provides mainly anterior cranial base exposure, with minimal middle fossa. An anterior clinoidectomy can be performed, but without any direct observation of the superior orbital fissure. Some MCF access can be accomplished if the lateral sphenoid wing is drilled inferiorly, leading to its highly versatile variant, the SupraTransOrb. CONCLUSIONS: All the aforementioned approaches use the sphenoid wing as skull base corridor from a specific orientation point; hence these are designated as transwing approaches. Their peculiarities mandate careful case selection for the effective and safe completion of the surgical goals.

Hidden in the Eyes-Recurrence of Systemic Hemopathies Reportedly "In Remission": Six Cases and Review of Literature.

Background and Objectives: Secondary ocular localizations of hematological malignancies are blinding conditions with a poor prognosis, and often result in a delay in the diagnosis. Materials and Methods: We describe a series of rare cases of ocular involvement in six patients with hematological malignancies, reportedly in remission, who presented secondary ocular localizations, challenging to diagnose. Two patients had an acute lymphoblastic leukemia (ALL) and developed either a posterior scleritis or a pseudo-panuveitis with ciliary process infiltration. One patient had iris plasmacytoma and developed an anterior uveitis as a secondary presentation. Two patients had a current systemic diffuse large B-cell lymphoma (DLBCL) and were referred either for intermediate uveitis or for papilledema and vitritis with secondary retinitis. Finally, one patient with an acute myeloid leukemia (AML) presented a conjunctival localization of a myeloid sarcoma. We herein summarize the current knowledge of ophthalmologic manifestations of extramedullary hematopathies. Results: Inflammatory signs were associated with symptomatic infiltrative lesions well displayed in either the iris, the retina, the choroid, or the cavernous sinus, from the admission of the patients in the ophthalmological department. These findings suggest that patients with ALL, AML, systemic DLBCL, and myeloma can present with ophthalmic involvement, even after having been reported as in remission following an effective systemic treatment and/or allograft. Conclusions: Early detection of hidden recurrence in the eyes may permit effective treatment. Furthermore, oncologists and ophthalmologists should be aware of those rare ocular malignant locations when monitoring patient's progression after initial treatment, and close ophthalmologic examinations should be recommended when detecting patient's ocular symptoms after treatment.

Clinical Features and Multimodal Imaging in Atypical Posterior Uveitis Secondary to Bartonella Henselae Infection.

PURPOSE: To characterize an unusual presentation of infectious posterior uveitis using multimodal imaging, and discuss the clinical decision-making involved in diagnosis and treatment. METHODS: Wide-field fundus photography, swept-source optical coherence tomography (OCT), swept-source OCT angiography, fluorescein angiography, and indocyanine green angiography. RESULTS: This patient presented with cyclical fevers and blurry vision. Fundus examination revealed bilateral optic disc edema, macular intraretinal white spots and many scattered yellow-white chorioretinal lesions. Multimodal imaging characteristics suggested that many of these lesions represent choroidal granulomas. Extensive systemic workup was only notable for borderline elevated Bartonella henselae IgG titers (1:128), however convalescent IgG titers were elevated at 38 days (1:512) supporting the diagnosis of Bartonella chorioretinitis. CONCLUSION: Ocular manifestations of Bartonella henselae infection are varied and may include choroidal granulomas. Multimodal imaging characteristics may help identify etiologies of infectious uveitis. Convalescent titers are important when evaluating patients with suspected Bartonellosis, especially patients with atypical presentations.

Venous sinus stenting shortens the duration of medical therapy for increased intracranial pressure secondary to venous sinus stenosis.

INTRODUCTION: Medical treatment, cerebrospinal fluid (CSF) shunting, and optic nerve sheath fenestration are standard treatments for increased intracranial pressure (ICP) in patients with idiopathic intracranial hypertension (IIH). Venous sinus stenting provides a novel alternative surgical treatment in cases of venous sinus stenosis with elevated ICP. METHODS: 12 consecutive subjects with papilledema, increased ICP, and radiological signs of dural sinus stenosis underwent cerebral venography and manometry. All subjects had papilledema and demonstrated radiological evidence of dural venous sinus stenosis. RESULTS: Six subjects chose venous stenting (Group A) and six declined and were managed conservatively with oral acetazolamide (Group B). The relative pressure gradient across the venous narrowing was 29±16.3 mm Hg in Group A and 17.6±9.3 mm Hg in Group B (p=0.09). The mean lumbar puncture opening pressure was 40.4±7.6 cm H2O in Group A and 35.6±10.6 cm H2O in Group B (p=0.4). Spectral domain optical coherence tomography (SD-OCT) showed mean average retinal nerve fiber layer (RNFL) thickness of 210±44.8 µm in Group A and 235±124.7 µm in Group B. However, the mean average RNFL thickness at 6 months was 85±9 µm in Group A and 95±24 µm in Group B (p=0.6). The total duration of acetazolamide treatment was 188±209 days in Group A compared with 571±544 days in Group B (p=0.07). CONCLUSIONS: In subjects with venous sinuses stenosis, endovascular stenting offers an effective treatment option for intracranial hypertension which may shorten the duration of medical therapy.

Lymphoma of the orbit masquerading as Tolosa-Hunt syndrome.

BACKGROUND: Tolosa-Hunt syndrome is a rare clinical syndrome characterized by painful ophthalmoplegia and ipsilateral cranial neuropathies. It is caused by an inflammatory process of unknown etiology. CASE PRESENTATION: We present a case of a 77-year-old white man with history of Waldenstrom's macroglobulinemia transforming to large B-cell lymphoma who presented to a community physician complaining of 4 months of isolated right retro-orbital pain and later with diplopia, ptosis, 6th nerve and pupil-sparing partial 3rd nerve palsies as well as progressive neurological findings. His clinical course was complicated by debilitating neurological symptoms and multiple hospitalizations leading to a delay in diagnosis caused by incomplete initial workup. CONCLUSION: This case is a reminder that lymphoproliferative disorders often mimic other neurologic disorders and that Tolosa-Hunt is a rare diagnosis that must be considered a diagnosis of exclusion.

Treatment of pediatric optic neuritis.

OPINION STATEMENT: Pediatric optic neuritis is a rare disorder causing a subacute loss of vision (often bilateral) in children, often of a severe degree. Common clinical findings include dense visual field loss, afferent pupillary defect (APD) in unilateral cases, and papillitis that is often bilateral. Contrary to optic neuritis in the adult population, the differential diagnosis for this disorder in pediatric patients is quite extensive, so neuroimaging and serologic evaluation are necessary to exclude an infectious or neoplastic process. Pediatric optic neuritis may occur as a clinically isolated syndrome, or in association with diffuse neurologic dysfunction, such as acute disseminated encephalomyelitis (ADEM). Optic neuritis may also be the first episode heralding the onset of pediatric multiple sclerosis or neuromyelitis optica (NMO or Devic's disease). Therefore, formal neurologic evaluation and follow-up are indicated. Although the management of this disorder in adults is well described, there is a paucity of evidence-based, prospective clinical data on its management and treatment in a pediatric population. The current treatment of pediatric optic neuritis consists of 3 to 5 days of intravenous methylprednisolone (4-30 mg/kg per day), followed by a prolonged oral corticosteroid taper. A prolonged course of oral steroid (2-4 weeks) is recommended to avoid recurrence, which is common in this age group. Some controversy persists concerning the exposure of children to high-dose parenteral corticosteroids to treat an entity that is usually self-limited, but given the severity of vision loss in one or both eyes in this population, this intervention is standard in neuro-ophthalmologic practice.

Decreased cortical activation in response to a motion stimulus in anisometropic amblyopic eyes using functional magnetic resonance imaging.

PURPOSE: Motion perception abnormalities and extrastriate abnormalities have been suggested in amblyopia. Functional MRI (fMRI) and motion stimuli were used to study whether interocular differences in activation are detectable in motion-sensitive cortical areas in patients with anisometropic amblyopia. METHODS: We performed fMRI at 1.5 T 4 control subjects (20/20 OU), 1 with monocular suppression (20/25), and 2 with anisometropic amblyopia (20/60, 20/800). Monocular suppression was thought to be form fruste of amblyopia. The experimental stimulus consisted of expanding and contracting concentric rings, whereas the control condition consisted of stationary concentric rings. Activation was determined by contrasting the 2 conditions for each eye. RESULTS: Significant fMRI activation and comparable right and left eye activation was found in V3a and V5 in all control subjects (Average z-values in L vs R contrast 0.42, 0.43) and in the subject with monocular suppression (z = 0.19). The anisometropes exhibited decreased extrastriate activation in their amblyopic eyes compared with the fellow eyes (zs = 2.12, 2.76). CONCLUSIONS: Our data suggest motion-sensitive cortical structures may be less active when anisometropic amblyopic eyes are stimulated with moving rings. These results support the hypothesis that extrastriate cortex is affected in anisometropic amblyopia. Although suggestive of a magnocellular defect, the exact mechanism is unclear.

Recognition of objects in non-canonical views: a functional MRI study.

BACKGROUND: The neural correlate of object recognition in non-canonical views is uncertain, but there is evidence for involvement of neural pathways, possibly separate from those used for object recognition in canonical views. METHODS: Boxcar functional MRI (fMRI) techniques were used to detect neural activity while eight normal subjects were instructed to identify digital photographs of objects in non-canonical and canonical orientations. RESULTS: The right angular gyrus, the left inferior temporal gyrus, and the right cerebellum showed significant fMRI activity during non-canonical as opposed to canonical viewing. CONCLUSIONS: Subjects recognizing objects in non-canonical orientations engage in a process separate from, or in addition to, the process used in recognizing objects in canonical orientations.

Decreased lateral geniculate nucleus activation in retrogeniculate hemianopia demonstrated by functional magnetic resonance imaging at 4 Tesla.

Functional magnetic resonance imaging (fMRI) can detect lateral geniculate nucleus (LGN) activation. We studied LGN function in 5 patients with retrogeniculate homonymous hemianopia using fMRI at 4.0 Tesla during binocular visual stimulation. Decreased activation of visual cortex and LGN on the side of the lesion was observed in all 5 patients. These findings suggest that retrogeniculate lesions are associated with decreased activation of the LGN, due to retrograde degeneration or a functional decrease caused by decreased feedback from ipsilateral visual cortex.

Eye dominance in the visual cortex using functional MRI at 1.5 T: an alternative method.

PURPOSE: To develop a functional MRI method for producing eye dominance histograms in humans at 1.5 Tesla (T). METHODS: In the first set of experiments, 8 normal persons were tested. The eye dominance of each voxel within the person's visually activated primary visual cortex was determined with Student t statistics during a left eye versus right eye contrast. Eye dominance distribution was plotted, and the mean t statistic was used to describe the histogram asymmetry. In the second set of experiments, the effect of monocular optical blur and decreased luminance via filter was studied, and eye dominance distributions were similarly determined. RESULTS: The eye dominance histogram in each of the 8 normals was approximately symmetric; the average mean t value was +0.13. All 4 subjects with the right eye blurred had histograms approximately symmetric or slightly shifted toward the left eye (average mean t = +0.56), and all 4 subjects with the right eye filtered had histograms dramatically shifted toward the left eye (average mean t = +2.22). The average mean t for the group with the right eye filtered was significantly different from that of the other 2 groups (P <.0001). CONCLUSIONS: With noninvasive methods in normal persons, functional magnetic resonance imaging techniques at 1.5 T were able to characterize the distribution of eye dominance of voxels in primary visual cortex, based upon their t statistic in the left eye versus right eye contrast. The method is sensitive to filtering but relatively insensitive to visual blur. This approach may have a future use in the study of amblyopia in humans.