Avoidance and Improvement in Visual Field Defect After Surgery for Metastatic Brain Tumors in the Parietal and the Occipital Lobe.

OBJECTIVE: Visual field defects occasionally occur secondary to tumors in the parietal and the occipital lobes. The aim of this study was to analyze the efficacy of improvement in hemianopsia after surgery for metastatic brain tumors involving or adjacent to the optic radiation (OR). METHODS: The study included 49 patients with brain metastasis in the parietal and occipital lobes in the present study. Preoperative and postoperative neurological assessments included visual field, Mini-Mental State Examination, and Karnofsky performance scale. RESULTS: Of 49 patients, 33 (67.3%) presented with preoperative homonymous hemianopsia. Of these 33 patients, the visual field was improved postoperatively in 17 patients (51.5%). In all patients regardless of preoperative hemianopsia, postoperative visual fields did not deteriorate. Tractography demonstrated that the OR was split by the tumor (n = 6) and fanning of fibers expanded along the lateral side of the tumor (n = 11). All tumors were removed via surgical access toward the medial side of the tumor. Gross total resection was achieved in most tumors in the group with visual improvement (n = 16/17; 94.1%). Improvement in the visual field was attributed to tumor location in the subcortical white matter, removal rate of the tumor, and higher postoperative Karnofsky performance scale score. CONCLUSIONS: The OR tended to deviate to the lateral side of the tumor in the parieto-occipital junction. The postoperative visual field improved even in cases of an occipital tumor. Based on the present study, total resection via an appropriate surgical route should be considered to preserve the OR, leading to improvement in the postoperative visual field.

Endoscopic Endonasal Approach for Giant Pituitary Adenoma Occupying the Entire Third Ventricle: Surgical Results and a Review of the Literature.

BACKGROUND: Pituitary macroadenomas occasionally disrupt the sellae diaphragma and extend directly to the third ventricle causing hydrocephalus. We present the results of a single-stage extended endoscopic approach for managing giant pituitary adenomas (GPAs) occupying the entire third ventricle. METHODS: A retrospective study of all GPAs occupying the entire third ventricle operated on via the endoscopic endonasal approach between January 2016 and December 2020 was performed. RESULTS: The study included 8 cases of GPA occupying the entire third ventricle, of which 2 (25%) were functioning adenomas. Of 8 patients, 4 (50%) presented with hydrocephalus, 2 underwent preoperative ventriculoperitoneal shunt, and 2 had an intraoperative external ventricular drain. No patients had postoperative cerebrospinal fluid rhinorrhea. Complete resection of the third ventricular component could be achieved in all cases radiologically; minimal residual tumor was present either in the lateral compartment of the cavernous sinus or over the anterior cerebral artery complex in 5 of 8 (62.5%) patients. Complete resolution of temporal hemianopia was seen in 8 of the 12 eyes (66.67%), and partial resolution was seen in 4 of 12 (33.3%) eyes. At a mean follow-up of 24.62 ± 10.01 months, none of the patients needed another surgical procedure. CONCLUSIONS: The extended endonasal endoscopic approach can be safely and efficiently used for single-stage excision of GPAs that disrupt the diaphragm and occupy the third ventricle. Preoperative cerebrospinal fluid diversion may be used to manage associated acute hydrocephalus in these cases.

Carotid-Falciform Optic Neuropathy: Microsurgical Treatment.

BACKGROUND: Several recent reports have implicated vascular ectasia and vessel contact in dysfunction of the visual apparatus. A subset of patients with prechiasmatic visual deterioration have an ectatic internal carotid artery (ICA) that displaces and flattens the optic nerve (ON) rostrally as the ON exits the skull base. We describe a proposed pathophysiologic mechanism and a straightforward surgical technique for dealing with this problem. METHODS: Via an ipsilateral pterional craniotomy, the bony roof of the optic canal is removed. The falciform ligament is opened in parallel to the ON. Adhesions between the ICA and ON are then dissected, and a Teflon pledget is placed between the ICA and ON to complete the decompression. RESULTS: Patients both in the literature and in this series experienced an improvement in their vision postoperatively. CONCLUSIONS: We propose that 3 mechanisms contribute to this caroticofalciform optic neuropathy: 1) mass effect from ICA ectasia, 2) ON irritation from vessel pulsatility, and 3) indirect compression by the falciform ligament from above. This disease process can be treated safely using standard microsurgical techniques with excellent outcomes.

Porphyromonas gingivalis causing brain abscess in patient with recurrent periodontitis.

We report an extremely rare case of Porphyromonas gingivalis causing brain abscess in a patient with recurrent periodontitis. The patient presented with right-sided homonymous hemianopsia and right hemiparesis. Emergent surgical drainage was performed and antibiotics were administered. P. gingivalis was identified from the anaerobic culture of the abscess. The clinical course of the patient improved with full recovery of the neurologic deficit.

Endoscopic Endonasal Approach to the Optic Canal: Anatomic Considerations and Surgical Relevance.

BACKGROUND: Increasing use of endoscopic endonasal surgery for suprasellar lesions with extension into the optic canal (OC) has necessitated a better endonasal description of the OC. OBJECTIVE: To identify the osseous OC transcranially and then investigate its anatomic relationship to the key endonasal intrasphenoidal landmarks. We also aimed to determine and describe the technical nuances for safely opening the falciform ligament and intracanalicular dura (surrounding the optic nerve [ON]) endonasally. METHODS: Ten fresh human head silicon-injected specimens underwent an endoscopic transtuberculum/transplanum approach followed by 2-piece orbitozygomatic craniotomy to allow identification of 20 OCs. After completing up to 270° of endonasal bony decompression of the OC, a dural incision started at the sella and continued superiorly across the superior intercavernous sinus. Subsequently the dural opening was extended anterolaterally across the dura of the prechiasmatic sulcus, limbus sphenoidale, and planum. RESULTS: Endonasally, the length of the osseous OC was approximately 6 mm and equivalent to the length of the lateral opticocarotid recess, as measured anteroposteriorly. The ophthalmic artery arose from the supraclinoidal carotid artery at approximately 2.5 mm from the medial osseous OC entrance. Transcranial correlation of the endonasal dural incision confirmed medial detachment of the falciform ligament and exposure of the preforaminal ON. CONCLUSION: The lateral opticocarotid recess allows distinction of the preforaminal ON, roofed by the falciform ligament from the intracanalicular segment in the osseous OC. This facilitates the preoperative surgical strategy regarding the extent of OC decompression and dural opening. Extensive endonasal decompression of the OC and division of the falciform ligament is feasible.

Intermittent visual field defects caused by a dilated Virchow-Robin space close to the optic radiation: Therapeutic and pathomechanical considerations.

OBJECTIVE: Virchow-Robin spaces (VRSs) are extensions of subarachnoid spaces that accompany vessels entering the brain. T2-weighted magnetic resonance imaging detects VRS in about 95 percent of patients in a recent study. VRSs are considered a normal variant with benign prognosis. Occasionally, VRS might become symptomatic causing neurological deficits depending on their location. CASE DESCRIPTION: We report the case of a 55-year-old female patient with dilated VRS presenting with visual field disturbances and cognitive deficits. The patient underwent endoscopic fenestration of a large periventricular VRS located next to the visual radiation into the posterior horn of the right lateral ventricle. During the postoperative course, visual field disturbances were resolved but cognitive deficits remained unchanged. CONCLUSION: Dilated VRSs can cause a variety of neurological deficits depending on their size and location. Therefore, patients harboring dilated VRS should undergo early close inspection and in case of progressive neurological deficits, an operative therapy should be done; as valve mechanisms can cause a reduction of size when brain scans are conducted and later lead to occurrence of severe neurological deficits during phase of dilation.

Primary sellar melanocytic tumor mimicking hemorrhagic pituitary macroadenoma: Case report and literature review.

Primary melanocytic tumors of the central nervous system (CNS) are rare lesions, but primary sellar tumors are rarer. Only 10 cases have been reported, and they are often misdiagnosed as pituitary macroadenoma. We report the case of a 54-year-old Chinese man who developed progressive bitemporal hemianopsia and visual loss. Magnetic resonance imaging (MRI) revealed an intrasellar and suprasellar clouded lesion adhering to the optic chiasm, hypothalamus, and hypophyseal stalk that was suspected of being a hemorrhagic pituitary macroadenoma. Because of the atypically giant, hemorrhagic, and upward-growing lesion, an initial trans-sphenoidal approach failed, and subsequent transfrontal craniotomy was adopted to achieve macroscopically complete resection. Histopathologic findings revealed a benign melanocytic tumor. Despite an extensive search, no other primary or secondary site was found. Considering the relatively benign lesion, effective surgery, and potential significant consequences of radiotherapy, the patient received no further treatment and is still alive at the 7-year follow-up. Primary sellar melanocytic tumors are exceptional lesions that are difficult to diagnose before operating and/or obtaining pathological findings. The pathological classification and extent of surgical resection may play a key role in the prognosis. Once this type of lesion is suspected, the transfrontal approach may achieve preferable exposure and resection. Complete surgical resection may be sufficient for relatively benign lesions; otherwise, stereotactic fractionated radiotherapy is indicated. More cases should be reported to improve the treatment strategy.

A boy with arachnoid cyst, a fall, and temporary and reversible visual impairment.

BACKGROUND: Temporal arachnoid cysts have been shown to interfere with the function of nervous structures, both cerebral cortex and cranial nerves. METHODS AND RESULTS: In this case report we describe a boy with a left temporal arachnoid cyst with a sudden onset of visual impairment 4 days after a mild trauma to the head. A perimetry test revealed a complete nasal hemianopia of the left eye, which normalized rapidly after an emergency craniotomy with cyst fenestration 3 hours after the patient experienced the reduced vision. CONCLUSIONS: The observed, reversible effect on vision is most probably caused by pressure exerted by the medial part of the cyst on the left optic nerve. We believe this is the first time such a case has been described.

Left-sided hemianopia as an unrecognized symptom of brain tumor and head injury.

Homonymous hemianopia (HH) is a visual field defect characterized by the involvement of two right or left halves of the visual field in both eyes. Patients with HH complain of difficulties with reading and scanning scenes in sufficiently rapid fashion to make sense of things as a whole. Some of these patients are not aware of their visual field defect. We report two cases of left-sided hemianopia in which visual field defects were detected "quite" accidentally. In the case of the first patient, revealing HH facilitated the detection of brain tumor and its treatment. In the case of the other patient, identifying HH, which was caused by a head injury, and making the patient aware of this fact, prevented potential harmful consequences associated with driving a car by a person with severe deficits in cognitive visual functions. homonymous hemianopia, brain tumor, head trauma.

Anatomical variant of origin of ophthalmic artery: case report.

We report on one case of variant origin of right ophthalmic artery (OA) from C4 choroidal segment of the right supraclinoid internal carotid artery. A 41-year-old woman affected by bitemporal hemianopsia performed Magnetic Resonance Imaging with gadolinium showing tuberculum sellae meningioma. During angiography we observed this variant of origin of OA. At surgical dissection, we observed this variant in carotid cistern.

Recurrence rates after neuroendoscopic fenestration and Gamma Knife surgery in comparison with subtotal resection and Gamma Knife surgery for the treatment of cystic craniopharyngiomas.

OBJECT: The object of this study was to compare the recurrence rates of cystic craniopharyngiomas after neuroendoscopic cyst fenestration combined with Gamma Knife surgery (GKS) and after subtotal resection (STR) combined with GKS. METHODS: The records of 27 patients (age range 3-66 years) with cystic craniopharyngiomas that were treated surgically or neuroendoscopically before GKS between January 2000 and December 2007 were reviewed to compare recurrence rates. The patients were divided into 2 groups: Group 1 (13 patients) received the neuroendoscopic procedure before GKS, and Group 2 (14 patients) received an STR followed by GKS. Tumor volumes, radiation doses, visual field defects, endocrine levels, and recurrences were compared between the 2 groups. Patients with solid tumors and those who underwent complete resection were excluded from the study. RESULTS: The recurrence rate for Group 1 was higher than that of Group 2 (p = 0.046). The radiation dose near the optic chiasm was higher in Group 1 (p = 0.021) than in Group 2. However, endocrine function was better preserved in Group 1 than in Group 2. CONCLUSIONS: This investigation confirms that STR followed by GKS results in a lower recurrence rate than neuroendoscopy and GKS. Neuroendoscopy and GKS, however, results in a better preservation of endocrine function. These results suggest that a generalized multimodal approach including endoscopic fenestration in addition to GKS is hindered by higher recurrence rates.

Pre-existing chiasma syndromes do not entirely remit following transsphenoidal surgery for pituitary adenomas.

BACKGROUND: It is not known whether following transsphenoidal surgery for pituitary adenomas the vision of patients with preoperative chiasma syndromes (CS) does improve to the degree of vision of patients without preoperative CS. OBJECTIVE: The purpose of this study is to answer the question above. METHODS: Pertinent data of a successive series of patients operated transsphenoidally for the first time for pituitary adenoma were retrospectively analysed. RESULTS: Of the 304 patients, 35.1% presented preoperatively with CS. The median visual acuity (VA) of these patients improved significantly from preoperative (right eye, 0.63 (0; 1.25); left eye, 0.56 (0; 1.4)) to postoperative (right eye, 0.8 (0; 1.25); left eye, 0.74 (0; 1.25)). The median number of impaired quadrants of the binocular visual fields (VF) improved significantly from preoperative (2 (0; 8)) to postoperative CS (0 (0; 4)). In patients without preoperative CS, postoperative vision (VA as well as VF) remained unchanged. Postoperatively, VA of patients with preoperative CS remained significantly lower than that of patients without preoperative CS (right eye, 0.96 (0.2; 1.4); left eye, 0.94 (0.05; 1.4)). Postoperatively, the number of impaired quadrants of the binocular VF of patients with preoperative CS remained significantly higher than in patients without preoperative CS (0 (0; 1)). CONCLUSION: In this unselected patient series, the vision (VA as well as VF) of patients with preoperative CS did not improved postoperatively to the degree of the vision of patients without preoperative CS. Thus, in patients with adenomatous chiasma compression transsphenoidal surgery may be indicated before CS develops.

Reversible hemianopsia caused by mechanical compression of the visual pathway by the dilated draining vein of an arteriovenous malformation--case report.

A 41-year-old woman presented with progressive hemianopsia caused by compression of the lateral geniculate body by the dilated basal vein draining a contralateral frontal arteriovenous malformation (AVM). Magnetic resonance (MR) imaging revealed left frontal AVM and right lateral geniculate body compression due to the dilated basal vein. Emergent presurgical transarterial embolization and surgical removal were performed. Left hemianopsia completely recovered 3 months after surgery and MR imaging indicated improvement of the compression of the lateral geniculate body. Direct mechanical compression of the enlarged drainage vein is one of the causes of homonymous hemianopsia. Early surgical treatment is recommended to obtain a rapid recovery.

Recovery from hemianopsia after surgical removal of spontaneous occipital haemorrhage.

In cases of spontaneous haemorrhage without severe impairment of consciousness, indications for surgical treatment remain controversial and the effect of surgery on focal deficits is unclear. We report the case of a young man operated for left occipital spontaneous haemorrhage (28 cm(3)) who had presented with right lateral hemianopsia without impaired consciousness. The visual field defect improved soon after the operation and resolved over the following months. The rationale for this approach is discussed.

[Bitemporal hemianopia in road traffic]. / Bitemporale Hemianopsie im Strassenverkehr.

BACKGROUND: Patients suffering from pituitary adenomas and diseases of the chiasma typically show a bitemporal hemianopia. The residual undisturbed nasal visual fields of both eyes should have an extension of (at least) 120 degrees and are according to the actual German traffic rules (FeVAndV) for cars of the classes A, B, M, L and T. The intact half fields fit geometrically to one virtual normal field, that seems to correspond in the centre of a normal field. Reports on this problem often do not address correctly the questions of suitability for participation in road traffic. PATIENTS: The case of a patient with typical bitemporal hemianopia illustrates the sensorial peculiarities: the functioning temporal retinal halves do not correspond. This patient suffered additionally from disturbing diplopia due to a small-angle exotropia. The extent of the performed eye muscle surgery was selected to induce a slight overcorrection, i. e., resulting in 3 to 5 degrees esotropia. This eliminated the diplopia, but resulted in a vertical scotoma of the extension of the esotropia. CONCLUSIONS: In bitemporal hemianopia the undisturbed nasal visual half fields do not add up to a "nearly normal field of one eye". Moreover, either diplopia or--much more dangerous in traffic--a central vertical scotoma is the result. The explanation for this is a sliding of the hemifields of each eye without stabilisation by corresponding areas of the retinas of the right and left eyes. The peripheral extension of the visual field is not the key to the problem to imagine how a patient with typical bitemporal hemianopia will visualise daily life and traffic. In bitemporal hemianopia there is substantially no eligibility for driving a car or motor bicycle in road traffic.

Form completion across a hemianopic boundary: behindsight?

Patients with homonymous hemianopia may report the completion of forms that overlap the vertical meridian of their field defects. While previous investigations of "hemianopic completion" have variously attributed to the disorder to inattention, residual vision or unstable fixation, we believe that our investigation has controlled for such potentially confounding factors. We report patient P.O.V. who experienced hemianopic completion in everyday life following a surgical lesion of his left occipital lobe. He showed normal spatial attention and normal spatial orienting: hemianopic completion can therefore occur in the absence of inattention. His completion was retinotopic and affected partial as well as complete forms: his hemianopic completion cannot be attributed to residual visual input or poor fixation. P.O.V.'s completion was also systematically affected by varying stimulus contrast and pattern masking. We argue that while other explanations may be appropriate for different cases, P.O.V.'s hemianopic completion reflects normal "constructive" visual processes and can be attributed to the unconstrained operation of visual routines that are normally involved in the perception of partially occluded forms. As such, this disorder has the potential to shed light on some of the most basic aspects of visual perception.

The cortical representation of foveal stimuli: evidence from quadrantanopia and TMS-induced suppression.

To address the extent to which the visual foveal representation is split, we examined a 29-year-old patient with a lower right quadrantanopia following surgical removal of the left occipital cortex above the calcarine sulcus and compared her performance with subjects receiving transcranial magnetic stimulation (TMS) over the occipital lobes. In a letter/digit classification task, the patient responded accurately to targets presented in the upper visual field, for all horizontal eccentricities. In the lower visual field, she failed to discriminate letters from digits when targets were presented in the right, but not the left visual field (RVF and LVF, respectively). This pattern was also true for the foveal targets, with poor performance to foveal-RVF (0.5 degrees to the right of fixation) but not foveal-LVF (0.5 degrees to the left of fixation) targets. Similar patterns of normal performance to LVF but not RVF or foveal-RVF targets were observed in a group of nine normal observers when TMS was applied over their left occipital cortex. Complementary impairments to LVF and foveal-LVF target classification were induced with TMS over the right occipital cortex. Thus, we have induced an hemianopic pattern in normal observers contralateral to the magnetically stimulated hemisphere. This correspondence between real and TMS-induced visual field defects is further evidence, in neurologically intact subjects, that the cortical representation of the fovea is split between the two hemispheres along the vertical meridian.

Ibotenic acid lesions in the pedunculopontine region result in recovery of visual orienting in the hemianopic cat.

Cats rendered hemianopic by a unilateral visual cortical ablation can recover the visual orienting response in the hemianopic visual field following disruption of the caudal non-tectotectal containing half of the commissure of the superior colliculus. Ibotenic acid lesions of a small 'critical zone' in the contralateral substantia nigra result in a similar recovery effect. A conceptual framework developed by Wallace et al. (1990) [J. Comp. Neurol. 296, 222-252] proposed that elimination of contralateral substantia nigra 'critical zone' inhibition on the superior colliculus ipsilateral to a visual cortical lesion is responsible for the recovery. This model is insufficient, however, to explain the observation that hemi-decorticate cats with contralateral substantia nigra 'critical zone' lesions which include but extend beyond the 'critical zone' do not demonstrate the recovery. In these cats, subsequent transection of the commissure of the superior colliculus does lead to the recovery. We hypothesize that another projection through the caudal commissure of the superior colliculus, from the pedunculopontine nucleus, is involved in the recovery effect. Visual orienting behavior was recorded before and after ibotenic acid lesions made in the pedunculopontine nucleus region contralateral to a visual cortical ablation in 16 cats. Four cats with lesions in a small rostral region of the contralateral pedunculopontine nucleus recovered the visual orienting response in the previously hemianopic visual field. Contralateral tectal projections from the pedunculopontine nucleus are thought to be cholinergic and terminate as distinct patches in the intermediate gray layers of the superior colliculus. Since this region of the pedunculopontine nucleus also receives GABA-ergic afferents from the substantia nigra, we propose that a subcortical neural circuit including the substantia nigra, pedunculopontine nucleus, and superior colliculus is involved in the recovery of visual orienting.