The Neurological Pupil index (NPi) is a standardized method for evaluating pupil reactivity that removes inter-examiner variability. Changes in the NPi can predict clinical deterioration in patients with traumatic brain injury (TBI); however, its use to predict visual impairment after the resection of parasellar meningiomas has not been described. A 71-year-old female underwent a modified expanded bifrontal craniotomy for resection of a 3.1 cm tuberculum sella meningioma that caused compression of the optic chiasm and resulted in left temporal and right superior temporal visual field deficits. Postoperatively, she lost vision in the right eye. Pupillometer measurements demonstrated an asymmetrically low NPi at that time, which improved to normal prior to partial vision recovery. The average NPi in the right pupil was 1.67 during the time of vision loss compared to 3.47 in the left pupil (p=1.7x10-10). Statistical analysis was performed with the Student's t-test and the significance level was set at p-value < 0.01. Resection of parasellar meningiomas is challenging because of the proximity of the optic apparatus. We report a case of unilateral vision loss after resection of a tuberculum sella meningioma in which the impaired eye's NPi value correlated closely with visual function. NPi values that decrease below 3 predict spikes in intracranial pressure in TBI patients; similarly, increases in the NPi value above 2.5-3 predict improvement in vision in the case reported here. By monitoring the proximal portion of the oculomotor reflex, the NPi can be a marker of visual impairment after surgery.

Background

Meningiomas of the atrium of the lateral ventricle present a unique operative challenge. Parietal transcortical approaches have been described with an oblique approach, but a strictly paramedian approach may offer advantages in a dominant hemisphere atrial meningioma.

Observations

The patient presented with several weeks of intermittent headaches. Magnetic resonance imaging (MRI) showed an enhancing intraventricular mass in the atrium of the left lateral ventricle. Three-dimensional reconstructions were created from a preoperative MRI, with 1-mm slices for neuronavigation. Diffusion tensor imaging (DTI) was obtained, and tracts were reconstructed in the patient's three-dimensional brainspace. DTI tractography delineated a paramedian transparietal corridor devoid of functional white matter tracks. The patient was positioned supine, in a semislouch position. A left parietal craniotomy was performed. Neuronavigation identified a gyrus posterior to the sensory cortex, anterior to the optic radiations and medial to superior longitudinal and arcuate fasciculus fiber tracts. The tumor was debulked to allow mobilization to coagulate capsular blood supply. Gross total resection was achieved. The patient was discharged postoperatively on day 3 without neurological deficits.

Lessons

A paramedian transparietal approach to a dominant hemisphere meningioma of the lateral ventricle can be a safe and effective way to resect tumors in this anatomically unique operative corridor.

Objectives We compare surgical exposures to the clivus by Le Fort I osteotomy (LFO) and the expanded endoscopic endonasal approach (EEEA). Methods Ten cadaveric specimens were imaged with 1.25-mm computed tomography. After stereotactic navigation, EEEA was performed followed by LFO. Clival measurements included lateral and vertical limits to the midline lower extent of exposure (t test). Results For EEFA and LFO, respectively, maximal lateral exposure in millimeters (mean ± standard deviation) was 24.5 ± 3.7 and 24.5 ±  - 3.8 (p = 0.99) at the opticocarotid recess (OCR) and 25.1 ±  - 4.1 and 24.1 ±  - 3.0 (p = 0.53) at the foramen lacerum level; lateral reach at the hypoglossal canals was 39.0 ±  - 5.88 and 56.1 ±   - 5.3 (p = 0.0004); and vertical extension was 56.0 ±  - 4.1 and 56.3 ±  - 3.4 (p = 0.78). Conclusions For clival exposures, LFO and EEEA were similar craniocaudally and laterally at the levels of the OCR and foramen lacerum. LFO achieved greater exposure at the level of the hypoglossal canal.

While the use of image-guided navigation is an excellent adjunct to the use of anatomical landmarks, dynamic changes that may occur in the position of critical structures are not accounted for during and after tumor resection. Unlike navigation, Doppler ultrasonography provides real-time imaging of the anterior skull base and can be used to accurately identify the location of vital structures during skull base surgery. A 56-year-old female initially presented with new onset left eye visual deficits. She previously underwent sublabial transsphenoidal subtotal resection of the tumor, confirmed as clival chordoma. She subsequently presented to our institution. She was treated with an expanded endonasal resection of the remaining chordoma followed by CyberKnife radiosurgery. Two years later, surveillance imaging identified tumor recurrence within the right clivus posterior to the carotid artery. Intraoperatively, in the previously operated irradiated skull base, the normal bony architecture of the sella was absent, resulting in the inability to distinguish the anterior genu of the internal carotid artery (ICA) from the adjacent tumor. Using Doppler ultrasonography, the course of the ICA was imaged in real time, allowing for safe, gross total tumor resection. In the setting of prior operation, radiation, or extensive disease, the normal bony architecture of the sella may be disrupted, placing the cavernous ICA at risk. We report what we believe is the first use of intraoperative ultrasound during the endoscopic endonasal approach in the setting of a previously operated, radiated sella.

Background Surgery for small vestibular schwannomas (Koos grade I and II) has been increasingly rejected as the optimal primary treatment, instead favoring radiosurgery and observation that offer lower morbidity and potentially equal efficacy. Our study assesses the outcomes of contemporary surgical strategies including tumor control, functional preservation, and implications of pathologic findings. Design Retrospective review. Setting/Participants Eighty consecutive patients (45 women, 35 men; mean: 47 years of age). Main Outcomes Measures Approaches included retrosigmoid approach (52%), translabyrinthine (40%), and middle fossa (8%). Operated on by the same surgical team, we analyzed presentation, radiographic imaging, surgical data, and outcomes. Results At last follow-up (mean: 34 months), 95% had good facial nerve function (House-Brackmann grade I or II); 36% who presented with serviceable hearing retained it; and 93% who presented with vestibular dysfunction reported resolution. Pathology identified two grade I meningiomas. Conclusions As one of the largest contemporary surgical series of small vestibular schwannomas, we discuss some nuances to help refine treatment algorithms. Although observation and radiosurgery have established roles, our results reinforce microsurgery as a viable, safe option for a subgroup of patients.

Objective Modern surgical experience with intracranial neuroenteric cysts is limited in the literature. We review our 15-year institutional experience with these rare lesions. Design Single-institution retrospective study. Setting Large North American tertiary care center. Participants Histologically confirmed cases of intracranial neuroenteric cyst from January 2000 to September 2014. Main Outcome Measures Pre- and postoperative modified Rankin Scale (mRS) scores, extent of resection, and postoperative complications are reported. Clinical presentation, imaging features, pathology, and operative approach are discussed. Results Five spinal and six intracranial neuroenteric cysts were surgically treated over a 15-year period. Median age at presentation for the intracranial cysts was 38.5 years. Mean cyst diameter was 3.8 cm. Five cysts were located in the pre-pontomedullary cistern, and one was located in the third ventricle. Gross total resection was achieved in four of the five posterior fossa cysts through a far lateral transcondylar approach. Postoperative complications included aseptic meningitis (one), transient abducens palsy (one), and pseudomeningocele requiring reoperation (three). Postoperative mRS scores improved to ≤1 by 6.5 months median follow-up. Conclusions Intracranial neuroenteric cysts are rare lesions with a variable imaging appearance. Complete surgical resection through a far lateral transcondylar approach is possible and usually results in symptom improvement or resolution.

BACKGROUND:Open transcranial approaches to the anterior skull base remain an integral component of current skull base practice. Evolution of these and other techniques has resulted in revisions of standard, tried-and-true methods in attempts to improve patient outcomes and cosmesis, while still providing the best combination of surgical exposure and ergonomics. OBJECTIVE:To describe a modified approach for midline tumors of the anterior skull base. METHODS:We describe the anatomy and techniques of a modified extended bifrontal craniotomy for anterior skull base tumors. Case examples and a postoperative 3-dimensional computed tomographic reconstruction of the craniotomy are provided. RESULTS:The technique has been employed with success in 3 tuberculum sellae meningiomas where the anterior limit of the tumor is several centimeters back from the inner table of the frontal bone. The mean distance from the tumor to inner table was 2.8 cm (range 1.3-3.8 cm). Mean tumor dimensions were 3.0 cm (transverse), 3.5 cm (anterior-posterior), and 2.2 cm (craniocaudal). Average operative time was 557 min. No cases had new T2/fluid-attenuated inversion recovery magnetic resonance imaging signal of the inferior frontal lobe to indicate retraction injury. CONCLUSION:The tailored extended bifrontal craniotomy for anterior skull base tumors provides adequate access to the anterior cranial fossa and has replaced our standard extended bifrontal approach. Keeping the osteotomy cut lines outside of the orbit reduces orbital swelling and mechanical disruption of conjugate eye movements in the early postoperative period, while allowing for minimal frontal lobe retraction and providing sufficient surgical exposure along the anterior skull base.

Arterial injuries are the most feared complication of endoscopic skull base surgery. During resection of the middle fossa component of a large ventral skull base chondrosarcoma, arterial bleeding was encountered near the right internal carotid artery (ICA). Durable hemostasis could not be achieved with packing and the patient was taken for an emergent angiogram that revealed a pseudoaneurysm of the proximal intradural ICA. Given the presence of good collateral flow through the anterior and posterior communicating arteries, the right ICA was sacrificed by coil embolization. The patient was taken back to the operating room for closure then transferred to the intensive care unit and maintained on vasopressors for five days to ensure adequate perfusion. The right ICA was coil embolized and the patient was taken back to the operating room for closure. The patient recovered without complication. Arterial injuries, although serious, are not always catastrophic. Critical steps are immediate recognition of bleeding, vascular imaging, and vessel sacrifice if necessary.

Rosai Dorfman disease is a rare histiocytic disorder of over-production of non-Langerhans histiocytes, which typically manifests with massive lymphadenopathy and sinonasal involvement. We report a rare case of systemic and disseminated craniospinal Rosai Dorfman disease with intraparenchymal and leptomeningeal involvement, but no sinus or dural-based disease. The diagnosis was established by biopsy of a hypothalamic mass. Additionally, UCSF500 Next Generation Sequencing demonstrated a solitary pathogenic alteration affecting the BRAF oncogene, which supports the morphologic and immunohistochemical diagnosis of Rosai-Dorfman disease.

Transitions in care are pivotal moments for patient safety. Although many strategies have been suggested for handoff improvement in the healthcare realm, little focus has been placed on patient safety during the transition from the operative to the postope