Anatomical Predictors of Transcranial Surgical Access to the Suprasellar Space.

Objective The suprasellar space is a common location for intracranial lesions. The position of the optic chiasm (prefixed vs. postfixed) results in variable sizes of operative corridors and is thus important to identify when choosing a surgical approach to this region. In this study, we aim to identify relationships between suprasellar anatomy and external cranial metrics to guide in preoperative planning. Methods T2-weighted magnetic resonance images (MRIs) from 50 patients (25 males and 25 females) were analyzed. Various intracranial and extracranial metrics were measured. Statistical analysis was performed to determine any associations between metrics. Results Interoptic space (IOS) size correlated with interpupillary distance (IPD; a = 7.3, 95% confidence interval [CI] = 4.5-10.0, R 2 = 0.3708, p = 0.0009). IOS size also correlated with fixation of the optic chiasm, for prefixed chiasms ( n = 7), the mean IOS is 205.14 mm 2 , for normal chiasm position ( n = 33) the mean IOS is 216.94 mm 2 and for postfixed chiasms ( n = 10) the mean IOS is 236.20 mm 2 ( p = 0.002). IPD correlates with optic nerve distance (OND; p = 0.1534). Cranial index does not predict OND, IPD, or IOS. Conclusion This study provides insight into relationships between intracranial structures and extracranial metrics. This is the first study to describe a statistically significant correlation between IPD and IOS. Surgical approach can be guided in part by the size of the IOS and its correlates. Particularly small intraoptic space may guide the surgeon away from a subfrontal approach.

Symptomatic Primary Tethered Optic Chiasm: Technical Case Report.

BACKGROUND AND IMPORTANCE: Symptomatic tethering of the optic nerves and chiasm is a rare occurrence and has been reported following both surgical and medical treatment of pituitary adenoma. Here we present a case of primary optic chiasm tethering in a patient with empty sella syndrome. CLINICAL PRESENTATION: The patient was a 61-yr-old female who presented with progressively worsening bitemporal hemianopsia. Magnetic resonance imaging (MRI) brain revealed an empty sella with herniation of the optic chiasm into the sella. The patient underwent an endoscopic, endonasal/trans-sphenoidal approach to the sella, where the optic chiasm was then detethered via lysis of arachnoid adhesions and ultimately buttressed with an abdominal fat graft. Postoperatively, the patient did well with subjective and objective improvements in her visual fields. CONCLUSION: We report a rare case of primary tethered optic chiasm, which was successfully treated via an endoscopic, endonasal approach with abdominal fat graft harvest.

A rare intracranial tumor consisting of malignant anaplastic and papillary meningioma subtypes.

BACKGROUND: Intracranial tumors with heterogeneous histopathology are a well-described pathologic entity. Pathologically, distinct tumors in direct contact with one another, also known as collision tumors are exceptionally rare, and collision between meningioma subtypes has not been previously described in the literature. CASE DESCRIPTION: A 79-year-old female with a history of breast carcinoma presenting with visual and motor deficits and imaging/intraoperative findings consistent with separate, distinct lesions. Histopathologic findings provided evidence for a collision between World Health Organization Grade III anaplastic and papillary meningioma. CONCLUSION: We report a possible collision tumor between two separate meningioma subtypes based on the unique radiologic, intraoperative, and histopathologic findings. Submission of multiple pathologic specimens during surgical resection is key for accurate histopathologic diagnosis.