Optochiasmatic Cavernomas: Updated systematic review and proposal of a novel classification with surgical approaches.

Cavernomas are histologically benign vascular malformations found at different sites in the brain. A rare site for such cavernomas, however, is the anterior optic pathway, comprising the optic nerve, chiasma, and optic tract-called optochiasmatic cavernomas (OCC). These lesions usually present with sudden onset or progressive vision loss, headache, and features mimicking pituitary apoplexy. In this paper, we describe a case of OCC operated at our center. We carry out an updated review of literature depicting cases of OCC, their clinical presentation, management, and postoperative complications. We also propose a novel classification system based on lesion location and further analyze these cavernoma types with respect to the surgical approach used and visual outcome. A 30-year-old lady had presented with a 3-week history of progressive bilateral vision loss and headache. Based on imaging, she was suspected to have a cavernous angioma of the chiasma and left optic tract. Due to progressive vision deterioration, the lesion was surgically excised using pterional craniotomy. Postoperatively, her visual symptoms improved, but she developed diabetes insipidus. Clinical and radiological follow-up has been done for 18 months after surgery. A total of 81 cases have been described in the literature, including the present case. Chiasmal apoplexy is the most common presentation. Surgical excision is the standard of care. Our analysis based on lesion location shows the most appropriate surgical approach to be used for each cavernoma type. Visual outcome correlates with the preoperative visual status. Visual outcome is good in patients presenting with acute chiasmal apoplexy, and when complete surgical excision is performed. The endonasal endoscopic approach was found to provide the best visual outcome. In addition to preoperative visual status, complete surgical excision predicts favorable visual outcomes in OCC. Our proposed classification system guides the appropriate surgical approach required for a particular location of the cavernoma.

Cavernous Malformation of the Optic Nerve and Chiasm: Prompt Suspicion and Surgery Matter.

BACKGROUND: Cavernous malformations (CMs) of the optic nerve and chiasm are extremely rare, accounting for less than 1% of all intracranial CMs. Acute, subacute, or progressive visual loss from CM may occur with or without hemorrhage. Prompt surgical excision of the CM offers the best hope to improve or stabilize vision. Given its rarity, optic nerve and chiasm CMs may not be readily suspected. We provide 3 cases of optic nerve and chiasm CM, highlighting key neuroimaging features and the importance of expedited intervention. METHODS: Case records of the neuro-ophthalmology clinics of the Bascom Palmer Eye Institute and the University of Colorado, and literature review of reported cases of optic CM. RESULTS: A 49-year-old woman reported acute progressive painless vision loss in the right eye. MRI showed a suprasellar mass with heterogeneity in signal involving the right prechiasmatic optic nerve. Surgical excision of the CM 5 days after onset of visual loss improved vision from 20/300 to 20/30. A 29-year-old woman with acute painless blurred vision in the right eye had anterior chiasmal junctional visual field defects corresponding to a heterogeneously minimally enhancing mass with blood products enlarging the optic chiasm and proximal right optic nerve. Surgical excision of the CM 8 weeks after onset of visual loss improved vision from 20/40 to 20/15 with improved visual fields. A 33-year-old woman with a history of familial multiple CMs, diagnosed at age 18, reported new-onset severe headache followed by blurred vision. MRI showed a hemorrhagic lesion of the optic chiasm and right optic tract. She was 20/20 in each eye with a reported left superior homonymous hemianopia. No intervention was recommended. Vision of the right eye worsened to 20/400 2 months later. The patient was followed over 13 years, and the MRI and visual function remained unchanged. Literature review yielded 87 optic CM cases occurring across gender and nearly all ages with visual loss and headache as the most common presenting symptoms. Optic chiasm is the most common site of involvement (79%). Nearly 95% of reported CM cases were treated with surgery with 81% with improved vision and 1% with worsened vision. CONCLUSION: MRI features are critical to the diagnosis of optic nerve and chiasm CM and may mimic other lesions. A high index of suspicion by the neuro-ophthalmologist and neuroradiologist leads to early recognition and intervention. Given optic CM displaces and does not infiltrate neural tissue, expedited surgical resection by a neurosurgeon after consideration of other diagnostic possibilities improves visual function in most cases.

Endoscopic endonasal surgical anatomy through the prechiasmatic sulcus: the key window to suprachiasmatic and infrachiasmatic corridors.

BACKGROUND: Classically, the transtuberculum and transplanum approaches have been utilized to reach the suprachiasmatic and infrachiasmatic corridors. The aim of this study was to provide a better understanding of the key endoscopic endonasal anatomy of the suprachiasmatic and infrachiasmatic corridors provided through selective removal of the prechiasmatic sulcus (SRPS). METHOD: A SRPS was performed in 16 sides of 8 alcohol-fixed head specimens. Twenty anatomical measurements were collected on the suprachiasmatic and infrachiasmatic corridors. The transplanum and transtuberculum approaches were also performed. RESULTS: In the suprachiasmatic corridor, the SRPS exposed the anterior communicating artery (AComm) and the post-communicating segment of the anterior cerebral arteries in all the cases, while the pre-communicating segment of the anterior cerebral arteries, recurrent arteries of Heubner, and fronto-orbital arteries were visualized in 75% (12/16), 31% (5/16), and 69% (11/16) of cases, respectively. In the infrachiasmatic corridor, the ophthalmic segment of the internal carotid artery and superior hypophyseal arteries were always visible through the SRPS. The mean width and height of the prechiasmatic sulcus were 13.2 mm and 9.6 mm, respectively. The mean distances from the midpoint of the AComm to the anterior margin of the optic chiasm (OCh) was 5.3 mm. The mean width of the infrachiasmatic corridor was 12.3 mm at the level of the proximal margin of the ophthalmic segment of the internal carotid artery. The mean distances from the posterior superior limit of the pituitary stalk to the basilar tip and oculomotor nerve were 9.7 mm and 12.3 mm, respectively. CONCLUSIONS: The SRPS provides access to the main neurovascular and cisternal surgical landmarks of the suprachiasmatic and infrachiasmatic corridors. This anatomical area constitutes the key part of the approach to the suprasellar area. To afford adequate surgical maneuverability, the transplanum or transtuberculum approaches are usually a necessary extension.

The use of quantitative pupillometry in patients with pituitary tumors: a technical note.

BACKGROUND: Pituitary tumors may cause compression of the optic chiasm, resulting in decreased visual acuity. Therefore, decompression of the optic chiasm is a major goal of surgical treatment in such patients. Quantitative pupillometry has been used in various clinical settings for assessing the optic system but has not been applied in patients with pituitary tumors. This study aimed to evaluate the potential of this technique to improve treatment modalities in patients undergoing surgical resection of pituitary tumors. METHOD: Pupillometry using the automated NPi 200® Pupillometer was performed in seven patients who underwent surgical resection of large pituitary tumors at the University of Heidelberg in 2018. The neurological pupil index (NPi) was assessed preoperatively and postoperatively, and correlations with visual acuity and magnetic resonance imaging (MRI) findings regarding optic chiasm compression were determined. RESULTS: All patients experienced visual disturbance due to a large pituitary tumor. The NPi was < 4.0 in all patients in at least one pupil. Intraoperative MRI demonstrated successful decompression of the optic chiasm in all cases. Postoperatively, the NPi values increased, and this increase was correlated with improved visual acuity. CONCLUSIONS: We found that quantitative pupillometry can detect optic chiasm compression in patients with pituitary tumors. Furthermore, postoperative improvement of NPi values may indicate sufficient decompression of the optic chiasm. Further studies are warranted to substantiate the granularity of this technique to gain valuable information for patients with pituitary tumors who are indicated for surgery.

How I do it: endoscopic endonasal chiasmopexy for optic chiasm prolapse.

BACKGROUND: Prolapse of the optic system into an empty sella is an unusual complication of the management of pituitary tumors. METHOD: We described the technical nuances for an endoscopic endonasal chiasmopexy, the indications for the procedure, and the caveats on the diagnosis of optic chiasm prolapse. CONCLUSION: The endoscopic endonasal chiasmopexy provides a direct route to lift the optic system. In most cases, the procedure may be achieved extradurally, protecting the chiasm from manipulation and postoperative fibrosis.

Bilateral chiasm and optic nerve micro-decompression in a child with extensive cranial fibrous dysplasia: how I do it.

BACKGROUND: Surgical decompression to the optic-chiasmatic region in craneofacial fibrous dysplasia (CFD) must be performed safely to improve or stabilize visual loss. METHOD: We describe a technical nuance when facing on a huge, deformed skull with potentially imbricated dura mater. Craniectomy was performed in concentric arches allowing to expose surgical field and elevated step by step. Bilateral micro-decompression was performed after without difficulties. CONCLUSIONS: Decompressing both optic nerves using this technique is safe and relatively simple to perform.

Increased frequency of cataract surgery in patients over age 50 with pituitary macroadenomas and chiasmal compression.

BACKGROUND: Patients with visual loss from macroadenomas compressing their optic apparatus may also have concomitant age-related visual pathology such as cataracts. How these two pathologies interact with each other is not well documented. OBJECTIVE: The interaction between these two pathologies in elderly patients is the subject of this study. METHODS: We identified a series of non-functioning macroadenoma patients over age 50 years with tumors compressing the chiasm who underwent transsphenoidal surgery at our institution between 2004 and 2018. Pre- and post-operative visual complaints, tumor size and extent of resection were analyzed. Prevalence of the diagnosis of cataract and prevalence of cataract surgery in each decade were compared with national averages. RESULTS: We identified 200 patients who met selection criteria. 18% of these patients had a diagnosis of cataract and 12.5% had cataract surgery. Compared with the Eye Diseases Prevalence Research Group (EDPRG) study, the prevalence of cataract surgery was 2.5 times the national average of 5.1%. 32% of these patients had no improvement in their vision after cataract surgery but 76% improved after transsphenoidal surgery. CONCLUSIONS: We reported a high prevalence of cataract surgery in patients over age 50 in patients with pituitary macroadenomas compressing the optic pathway compared with national averages in patients without adenomas. While visual loss from adenoma likely precipitated more cataract surgeries in this group of patients, some who may not have required it, those patients with cataracts who did not have their cataracts extracted were less likely to recover vision after transsphenoidal surgery. Addressing both pathologies is beneficial.

Chordoid Glioma Infiltrating Optic Structures.

Chordoid glioma of the third ventricle (CGTV) is a rare, slow-growing, World Health Organization Grade II glial tumor, with stereotyped localization in the anterior third ventricle. Despite being considered a noninvasive tumor, CGTV is usually associated with a poor clinical outcome due to its close proximity to important cerebral structures, such as the hypothalamus and visual pathways. Our patient with CGTV experienced visual involvement, but after subtotal surgical resection showed no evidence of progression at 5-year follow-up.

Treatment of empty sella associated with visual impairment: a systematic review of chiasmapexy techniques.

PURPOSE: Chiasmapexy is a poorly described surgical procedure adopted to correct the downward displacement of suprasellar visual system (SVS) into an empty sella (ES) causing visual worsening. The aim of our study is to define the indications for extradural and intradural chiasmapexy. METHODS: A systematic literature review has been performed on MEDLINE database (US National Library of Medicine), including only articles that depicted cases of surgically treated patients affected by ES and progressive delayed visual worsening. Moreover, we have reported three cases of secondary ES syndrome (SESS) with visual worsening treated in our Department with transsphenoidal (TS) microsurgical intradural approach. Finally, we have compared the results of extradural and intradural chiasmapexy described in literature. RESULTS: The etiology of visual impairment is different in primary and secondary ESS. In primary ESS (PESS) the only predisposing factor is a dehiscence of diaphragma sellae, and the anatomical distortion caused by displacement of optic chiasm or traction of pituitary stalk and infundibulum may determine a direct injury of neural fibers and ischemic damage of SVS. In PESS the mechanical elevation of SVS performed through extradural approach is sufficient to resolve the main pathologic mechanism. In SESS, arachnoidal adhesions play an important role in addition to downward herniation of SVS. Consequently, the surgical technique should provide elevation of SVS combined to intradural release of scar tissue and arachnoidal adhesions. In treatment of SESS, the intradural approaches result to be more effective, guaranteeing the best visual outcomes with the lowest complications rates. CONCLUSIONS: The intradural chiasmapexy is indicated in treatment of SESS, instead the extradural approaches are suggested for surgical management of PESS.

Endoscopic Transsphenoidal Surgery for an Adult Patient With Giant Exophytic Chiasmatic/Hypothalamic Glioma.

Optic pathway hypothalamic gliomas are intrinsic low-grade gliomas involving the optic nerve, chiasm, optic tract, and hypothalamus. The rarity of these tumors and their unpredictable course make assessment and standardization of treatment modalities difficult. Tumor debulking via various transcranial approaches was considered to be effective at controlling tumor growth, but with high rates of severe surgery-related complications. In the present case, endoscopic transsphenoidal surgery was initiated to debulk the exophytic chiasmatic/hypothalamic glioma with good preservation of hypothalamic and endocrine functions. The authors suggest transsphenoidal surgery with tumor debulking could be an effective and safe treatment for patients with chiasmatic/hypothalamic gliomas.

Prechiasmatic sulcus and optic strut: an anatomic study in dry skulls.

BACKGROUND: Although safe surgical access to the cavernous sinus is related to understanding the anatomical and ethnic variants of the prechiasmatic sulcus and the optic strut, there remains a paucity of studies of the morphology and the bony relationships in the region. The present study provides a systematic morphological and morphometric analysis of the sulcal region and the optic strut anatomy and their relations in a Greek population. METHODS: The interoptic distance, length of planum sphenoidale, sulcal length and sulcal angle was determined in 96 Greek adult dry skulls. The prechiasmatic sulci and optic struts were morphologically classified and association of sulcal region measures according to type of prechiasmatic sulcus and optic strut were examined. RESULTS: Mean interoptic distance was 1.69 ± 0.25 cm; sulcal length, 0.72 ± 0.18 cm; length of planum sphenoidale, 1.86 ± 0.32 cm; sulcal angle, 24.05 ± 17.17°. The sulcal angle was significantly smaller in female skulls compared to males (14.82 ± 12.43 vs 28.29 ± 15.24; p < 0.05). Type I (narrow, steep) prechiasmatic sulci were the most commonly observed (35.8%), followed by Type IV (wide, flat) (32.1%), Type II (narrow, flat) (18.5%) and, finally, Type III (wide, steep) sulci (13.6%). The optic strut was presulcal in 8.3% of specimens, sulcal in 31%, postsulcal in 41.7% and asymmetric in 19%. CONCLUSIONS: The present study augments the current knowledge of the morphology of key anatomical landmarks, prechiasmatic sulcus and the optic strut, for cavernous sinus surgery and indicates population and gender differences. We report significant anatomical variations in the prechiasmatic sulcus, optic strut and surrounding structures. In addition to providing a better understanding of the anatomical landmarks, necessary for the safe navigation in transcranial and endoscopic procedures, the present results also suggest that surgeons must consider population differences in determining the anatomical landmarks and navigation points in the sellar region.

Intrachiasmatic abscess caused by IgG4-related hypophysitis.

INTRODUCTION: Autoimmune hypophysitis is a rare disease of the pituitary, which may affect vision by inflammation and compression of the optic chiasm. However, intrachiasmatic abscess formation has not been previously reported. METHODS: In this study, we report a case of a 29-year-old female with bitemporal hemianopia due to a cystic intrasellar tumor. The patient underwent surgical decompression of the lesion, which was found to be an intrachiasmatic abscess. RESULTS: The histologic findings were consistent with IgG4 hypophysitis. CONCLUSION: This rare clinical presentation suggests that in case of a disproportionate degree of visual impairment in relation to the size of the lesion, suspicion should lead to an intrachiasmatic lesion.

[The extended endoscopic endonasal transsphenoidal approach in surgery for epidermoid cysts of the chiasmatic region]. / Ispol'zovanie rasshirennogo transsfenoidal'nogo éndoskopicheskogo éndonazal'nogo dostupa v khirurgii épidermoidnykh kist khiazmal'noi oblasti.

Surgical treatment for epidermoid cysts of the chiasmatic region is a challenge because of the tendency to a massive spread of epidermoid masses through the cerebrospinal fluid pathways and a significant lesion deviation from the midline. PURPOSE: To analyze capabilities of the extended endoscopic endonasal transsphenoidal approach in surgery for epidermoid cysts. MATERIAL AND METHODS: The study included 6 patients with epidermoid cysts of the chiasmatic region who were operated on using the extended anterior endoscopic endonasal transsphenoidal approach at the Burdenko Neurosurgical Institute in the past 5 years. RESULTS: Epidermoid masses were completely removed in 5 patients; in none of the cases, complete removal of the epidermoid cyst capsule was achieved. There were no cases of vision deterioration and the development of new focal neurological symptoms. One female patient developed hypopituitary disorders in the postoperative period. There was no recurrence of epidermoid cysts during follow-up. CONCLUSION: Removal of epidermoid cysts of the chiasmatic region using the extended anterior endoscopic transsphenoidal approach may be an alternative to transcranial microsurgery.

Subfrontal trans-lamina terminalis approach to a third ventricular craniopharyngioma.

Craniopharyngiomas are benign, partly cystic epithelial tumors that can rarely occur in a retrochiasmatic location with involvement of the third ventricle. The lamina terminalis is an important neurosurgical corridor to these craniopharyngiomas in the anterior portion of the third ventricle. We present a video case of a large midline suprasellar and third ventricular craniopharyngioma in a 32-year-old male with visual disturbances. The tumor was approached with a subfrontal translamina terminalis exposure, and a gross-total resection of the tumor was achieved. This surgery involved working through a lamina terminalis fenestration around the optic nerve, optic chiasm, optic tracts, and the anterior communicating artery complex. This video illustrates the techniques employed in performing a transbasal anterior skull base approach to the third ventricle and demonstrates vivid surgical anatomy of neurovascular structures around the lamina terminalis. The video can be found here: https://youtu.be/fCYMgx8SnKs .

Using the trans-lamina terminalis route via a pterional approach to resect a retrochiasmatic craniopharyngioma involving the third ventricle.

Retrochiasmatic craniopharyngiomas involving the anterior third ventricle are challenging to access. Although the pterional approach is a common route for suprasellar lesions, when the craniopharyngioma extends behind the chiasma into the third ventricle, access is even more difficult, and the lamina terminalis may offer a good working window. The translamina terminalis approach provides direct access to the retrochiasmatic portion of the tumor with minimal brain retraction and no manipulation of the visual nerves. In this video, we emphasize the utility of using the lamina terminalis corridor to resect the retrochiasmatic intraventricular portion of a craniopharyngioma. The video can be found here: https://youtu.be/hrLNC0hDKe4 .

[Chiasm and optic nerve glioma manifested as hemorrhage (two clinical cases and a literature review)]. / Glioma khiazmy i zritel'nykh nervov, proiavivshaiasia krovoizliianiem (dva klinicheskikh nabliudeniia i obzor literatury).

The article presents two rare clinical cases of low-grade (WHO grade I-II) glioma of the anterior visual pathway structures, the chiasm and optic nerves, in adults. The feature of these cases was the benign nature of a chiasm and optic nerve glioma in adults as well as its presentation in the form of hemorrhage to the tumor and parenchymal and subarachnoid space, which to some extent complicated making the correct diagnosis. Removal of an intracerebral hematoma and open tumor biopsy were performed in one case, and removal of a hematoma and partial tumor resection followed by radiotherapy were performed in the other case.

The role of diffusion tensor tractography in the surgical treatment of pediatric optic chiasmatic gliomas.

Diffusion tensor tractography(DTT) can theoretically be used in assessing the optic chiasmatic glioma(OCGs),which are still in debate about optimal treatment. The purpose of this study was to investigate the role of this technology in offering more information about the tumor, assisting the debulking surgery, and helping to anticipate visual outcomes. As a prospective cohort study, the enrolled patients received routine pre- and postoperative neuro-ophthalmology, neuroimaging, and endocrine examinations. Fiber tractography was meanwhile performed based on diffusion tensor imaging examination. Identification of the position relationship between the lesions and residual optic path, and morphology analysis of them was done based on their DTT features. All the information was used for confirmation by the intraoperative findings. 11 pediatric patients were enrolled in this study. Most of them got subtotal resection of the tumors and stable postoperative visual outcomes. On the DTT imagings, the tumors were divided into infiltrative endophytic ones (TypeI) and inflated ones (TypeII), which can be subclassified as inferior and superior chiasmatic ones based on the positional relationships between the optic chiasm fibers and the tumors. These positional relationships were confirmed intraoperatively. The postoperative DTT images were quite different from preoperative ones. The application of DTT to children with OCGs is feasible, and valuable for getting more information about the disease, improving surgical techniques, and helping predict the overall and visual prognosis of the patients. The exact correlations of DTT features and visual outcomes need to be further verified.

Physiological Correlates and Predictors of Functional Recovery After Chiasmal Decompression.

BACKGROUND: The intrinsic abilities and limits of the nervous system to repair itself after damage may be assessed using a model of optic chiasmal compression, before and after a corrective surgical procedure. METHODS: Visual fields (VFs), multifocal visual evoked potentials (mfVEP), retinal nerve fiber layer (RNFL) thickness, and diffusion tensor imaging were used to evaluate a patient before and after removal of a meningioma compressing the chiasm. Normally sighted individuals served as controls. The advantage of each modality to document visual function and predict postoperative outcome (2-year follow-up) was evaluated. RESULTS: Postsurgery visual recovery was best explained by critical mass of normally conducting fibers and not associated with average conduction amplitudes. Recovered VF was observed in quadrants in which more than 50% of fibers were identified, characterized by intact mfVEP latencies, but severely reduced amplitudes. Recovery was evident despite additional reduction of RNFL thickness and abnormal optic tract diffusivity. The critical mass of normally conducting fibers was also the best prognostic indicator for functional outcome 2 years later. CONCLUSIONS: Our results highlight the ability of the remaining normally conductive axons to predict visual recovery after decompression of the optic chiasm. The redundancy in anterior visual pathways may be explained, neuroanatomically, by overlapping receptive fields.

Relationship between the pituitary stalk angle in prefixed, normal, and postfixed optic chiasmata: an anatomic study with microsurgical application.

BACKGROUND: The relationship between the optic apparatus and the skull base is important during approaches near the sella turcica. One relationship that dictates which approach is taken is whether the optic chiasm is prefixed or postfixed or in a "normal" location, (centered over the diaphragma sella). The relationship between the position of the chiasm and the angulation of the pituitary stalk has not been investigated. METHODS: Forty adult cadavers without intracranial pathology were dissected and parasagitally hemisected lateral to the sella turcica. The angulations between the pre- and postfixed and normal chiasm and the pituitary stalk were evaluated under magnification. Additionally, 50 MRIs performed among patients evaluating headache were analyzed for these relationships. RESULTS: For cadavers, the chiasm was prefixed in 7.5% (n = 3), normal in 85% (n = 34), and postfixed in 7.5% (n = 3). On imaging, the chiasm was prefixed in 4% (n = 2), normal in 88% (n = 44), and postfixed in 8 % (n = 4). For all, the relation between the type of chiasm and the pituitary stalk was more often (p < 0.05) 90° or greater for prefixed chiasmata and acute angles for normal or postfixed chiasmata. CONCLUSIONS: These data may assist skull base surgeons when approaching pathology near the optic chiasm and pituitary stalk.

Intraoperative fat placement in surgically refractory parasellar neoplasms to facilitate stereotactic radiosurgery.

BACKGROUND: In this article, we report on the technique of placing fat in between a sellar or parasellar neoplasm and the optic chiasm to possibly protect the optic chiasm from sequelae of radiation. METHODS: A review was performed on three patients, each of whom had planned subtotal resection with fat placed near their optic chiasm to facilitate future radiosurgery. RESULTS: Follow-up on our three patients varied from 6 months to 3 years post-stereotactic radiosurgery. The fat remained stable and in place. The tumors either remained stable or reduced in size. No infections, postoperative marker dependent neurological complications or unusual symptoms were encountered. CONCLUSIONS: Placement of fat between a parasellar neoplasm and the optic chiasm appears to be a safe approach to help define the tumor chiasm space, helping to facilitate radiosurgery. Future experience is warranted to determine the efficacy of this technique.