Response to Preoperative Dexamethasone Predicts Postoperative Neurological Improvement of Focal Neurological Deficits in Patients With Brain Metastases.

BACKGROUND: Steroids are used ubiquitously in the preoperative management of patients with brain tumor. The rate of improvement in focal deficits with steroids and the prognostic value of such a response are not known. OBJECTIVE: To determine the rate at which focal neurological deficits respond to preoperative corticosteroids in patients with brain metastases and whether such an improvement could predict long-term recovery of neurological function after surgery. METHODS: Patients with brain metastases and related deficits in language, visual field, or motor domains who received corticosteroids before surgery were identified. Characteristics between steroid responders and nonresponders were compared. RESULTS: Ninety six patients demonstrated a visual field (13 patients), language (19), or motor (64) deficit and received dexamethasone in the week before surgery (average cumulative dose 43 mg; average duration 2.7 days). 38.5% of patients' deficits improved with steroids before surgery, while 82.3% of patients improved by follow-up. Motor deficits were more likely to improve both preoperatively ( P = .014) and postoperatively ( P = .010). All 37 responders remained improved at follow-up whereas 42 of 59 (71%) of nonresponders ultimately improved ( P < .001). All other clinical characteristics, including dose and duration, were similar between groups. CONCLUSION: A response to steroids before surgery is highly predictive of long-term improvement postoperatively in brain metastasis patients with focal neurological deficits. Lack of a response portends a somewhat less favorable prognosis. Duration and intensity of therapy do not seem to affect the likelihood of response.

Innovative growth and development of a neurological surgery residency cadaveric skull base simulation training program: A single institution experience.

OBJECTIVE: Neurosurgical cadaveric and simulation training is a valuable opportunity for residents and fellows to develop as neurosurgeons, further neuroanatomy knowledge, and develop decision-making and technical expertise. The authors describe the growth and development of Oregon Health & Science University (OHSU) Department of Neurological Surgery (NSG) resident hands-on simulation skull base course and provide details of course layout and setup. METHODS: A three-part surgical simulation series was created to provide training in cadaveric skull base procedures. Course objectives were outlined for participants. Residents participated in NSG hands-on simulation courses (years 2015-2020) and completed annual course curriculum and anonymous course evaluations, which included free text reviews. Courses were evaluated by Likert scale analysis within Python, and free text was quantified using Valence Aware Dictionary for sEntiment Reasoning (VADER). Descriptive statistics were calculated and plotted using Python's Seaborn and Matplotlib library modules. RESULTS: Analysis included 162 skull base (anterior fossa, middle fossa and lateral, and endoscopic endonasal-based) simulation course evaluations. Resident responses were overwhelmingly positive. Likert responses demonstrated high average responses for each question (4.62 ± 0.56 and above). A positive attitude about simulation courses is supported by an average compound sentiment value of 0.558 ± 0.285. CONCLUSION: This is the first time Likert responses and sentiment analysis have been used to demonstrate how neurosurgical residents view a comprehensive, multi-year hands-on simulation training program. We hope the information presented serves as a guide for other institutions to develop their own residency educational curriculum in cadaveric skull base procedures.

A technical note on anterolateral mobilization in vertebrobasilar dolichoectasia for relief of brainstem compression.

Vascular compression of neural tissue causing neurological symptoms is a wellknown phenomenon. This is commonly seen in trigeminal neuralgia and, less commonly, in hemifacial spasm by small arteries, which can be treated by microvascular decompression. Rarely, larger arteries, such as the vertebral arteries, may compress the brainstem. This can lead to symptoms of pontine or medullary distress like hemiparesis, dysphagia, or respiratory distress. This is treated by macrovascular decompression. Due to the rare and heterogenous nature of this disease, there is no standardized approach. We describe a novel technique whereby the vertebrobasilar system is mobilized anterolaterally towards the occipital condyle with a sling to decompress the brainstem.
We report two cases of vertebrobasilar dolichoectasia causing brainstem compression. A carotid patch graft sling with anterolateral mobilization to the occipital condyle is described as a surgical nuance to macrovascular decompressive surgery. Briefly, the vertebral artery was identified and dissected away from the brainstem and the bulbar cranial nerves. Bovine pericardium graft was used to create a sling around the artery by suturing the two ends together. The sling was then fixed either to the occipital condyle using cranial plating screws or suturing to the dura of the occipital condyle.
A novel surgical technique for management of vertebrobasilar dolichoectasia causing brainstem compression with progressive neurological deterioration is reported. Anatomical location and the offending vessel should guide neurosurgeons to select the best surgical option to achieve complete decompression of the involved neural structures.

Endoscopic Endonasal Eustachian Tube Obliteration as a Treatment for Tension Pneumocephalus After Translabyrinthine Resection of Vestibular Schwannoma.

OBJECTIVE: Cerebrospinal fluid leak and pneumocephalus are rare but potentially devastating complications associated with translabyrinthine resection of cerebellopontine angle masses. Persistent pneumocephalus despite proximal eustachian tube (ET) obliteration is rare. We describe, to our knowledge, the first report of successful management of tension pneumocephalus by endoscopic endonasal ET obliteration using a novel V-loc (Covidien; Medtronic, Minneapolis, MN) suture technique. PATIENTS: A 63-year-old man presented with altered mental status 10 months after translabyrinthine excision of a left cerebellopontine angle vestibular schwannoma measuring 2.8 × 2.9 × 3.3 cm. Computed tomography demonstrated diffuse ventriculomegaly and new pneumocephalus along the right frontal lobe, lateral ventricles, and third ventricle, and air within the left translabyrinthine resection cavity. INTERVENTION: The patient underwent left-sided endoscopic endonasal ET obliteration using 2-0, 9-inch V-loc suture. MAIN OUTCOME MEASURE: Postoperatively, the patient's mental status improved with a decrease in size of the lateral and third ventricles on computed tomography. CONCLUSION: Endoscopic endonasal ET obliteration, a technique previously applied to recalcitrant cerebrospinal fluid leaks, is a safe and reasonable alternative to reentering the original surgical site for patients with pneumocephalus after lateral skull base surgery. Utilizing a V-loc suture for this technique instead of a traditional suture may improve procedural ease and speed.

Endoscopic Endonasal Eustachian Tube Obliteration for Cerebrospinal Fluid Rhinorrhea: A Case Series and Scoping Review.

BACKGROUND: Endoscopic endonasal eustachian tube obliteration (EEETO) is a valuable option for treating cerebrospinal fluid rhinorrhea (CSFR) after lateral skull base surgery. Several small case series describe different techniques because of the rarity of this indication. OBJECTIVE: To review available literature on EEETO focusing on technique and factors affecting success. We also contribute a new case series using a knotless barbed suture technique. METHODS: This was a retrospective chart review of EEETO using barbed suture for CSFR at our institution from 2018 to 2021. Scoping review was performed by searching PubMed for articles on EEETO for CSFR. Patients were pooled for data syntheses. RESULTS: Our retrospective series contained 7 patients. Two patients (28.6%) required revision, but all were ultimately successful. Six studies were identified in scoping review for a combined total of 23 patients. Most of the patients initially underwent translabyrinthine (52.2%) resection of vestibular schwannoma (82.6%). Average time to initial CSFR was 362.6 days (standard deviation ± 1034.2, range 0-4320 days). Twenty-two patients underwent lumbar drain, and 11 underwent prior surgical attempts before EEETO. The initial success rate of EEETO was 65.2%. In 8 patients needing revision, EEETO was ultimately successful in 6. There were no differences in demographics or presentation between successful and revision cases. Seven different techniques were described. CONCLUSION: EEETO can treat CSFR after lateral skull base surgery. Revision surgery is common and difficult to predict. Several techniques have been described, and utilization of barbed suture is a viable method with comparable success, but without the need for endoscopic knot tying.

Opioid use after endoscopic skull base surgery: A descriptive, prospective, longitudinal cohort study.

BACKGROUND: Opioid abuse is a public health crisis and the perioperative period can be a time of first opioid exposure. Little is known about postoperative pain management after endoscopic skull base surgery (ESBS). METHODS: This investigation was a single-institution, longitudinal, prospective cohort study of adult patients undergoing ESBS between November 2019 and March 2020. Participants completed preoperative questionnaires and were contacted every 48 hours postoperatively to quantify pain and opioid consumption. RESULTS: A total of 33 patients were enrolled and 28 of 33 patients (85%) underwent ESBS for sellar pathology. Mean total morphine milligram equivalents (MME) consumed was 381.9 ± 476.0. History of a headache disorder (p = 0.025) and previous opioid use within 60 days preoperatively (p < 0.001) were significantly associated with greater opioid use. Mean duration of opioid use was 6.7 ± 5.1 (range, 0-20) days. Headache disorder (p = 0.01), depression (p = 0.03), anxiety (p = 0.03), age ≤46 years (p = 0.029), and previous opioid use (p = 0.008) were all associated with longer mean opioid use. Patients with headache disorder also reported higher mean postoperative pain scores. Fewer than half of the participants required opioids by postoperative day 8. Prescription of nonsteroidal anti-inflammatory drugs at discharge was significantly associated with less outpatient opioid use (p = 0.032). At 2-month follow-up, 37% of patients reported keeping excess opioids. CONCLUSION: After ESBS, greater total opioid use was significantly associated with history of headaches and previous opioid use within 60 days. Overall, opioid use declined among all patients in the postoperative period, but several factors may contribute to longer duration of use.

Determinants of survival in sinonasal and skull base chondrosarcoma: An analysis of the National Cancer Database.

BACKGROUND: Chondrosarcomas are rare, malignant chondroid tumors that can occur in the sinonasal and skull base regions. Surgery is a mainstay of treatment, but complete resection can be challenging because of the close proximity of critical neurovascular structures. Because of their rarity and relatively indolent nature, optimal treatment regimens are not established. Our objective was to assess determinants of survival for sinonasal and skull base chondrosarcomas utilizing the National Cancer Database (NCDB). METHODS: The NCDB (2004-2017) was queried for cases of sinonasal and skull base chondrosarcoma. Multivariate hazard regression modeling was used to identify significant predictors of 60-month and 120-month overall survival (OS). RESULTS: Seven hundred thirty-six cases met inclusion criteria. OS for all treatment types was 84.7% [SE±0.02] at 60 months and 75.6% [SE±0.02] at 120 months. Surgery with or without adjuvant treatment was found to associate with highest OS at 60 and 120 months. For patients receiving adjuvant radiation during treatment, proton therapy had significantly better OS at 60 months (95.4% [SE±0.03] vs 82.3% [SE±0.03], -2  = 5.27; p = 0.02) and 120 months (85.1% [SE±0.08] vs 72.8% [SE±0.05], -2  = 4.11; p = 0.04) compared with conventional external beam. After adjustment for primary site, multivariate Cox regression modeling (n = 561) identified cofactors significantly associated with variation in mortality risk at 60 and 120 months, including age, Charlson-Deyo total score ≥ 3, insurance provision status, and tumor grade. CONCLUSIONS: Sinonasal and skull base chondrosarcoma are primarily treated with surgery with favorable OS. Adjuvant treatment may be required and proton radiation was associated with improved 60-month and 120-month survival compared with conventional radiation.

Regression of Multiple Meningiomas after Discontinuation of Chronic Hormone Therapy: A Case Report.

Introduction Meningiomas are more common in females and frequently express progesterone and estrogen receptors. Recent studies have revealed a high incidence of meningiomas in situations in which estrogen/progesterone levels are increased such as pregnancy, gender reassignment therapy, and fertility treatment. While the relationship remains unclear and controversial, these findings suggest exposure to high levels of endogenous or exogenous hormones may increase the risk of developing a meningioma. Patients and Methods A 40-year-old female with a history of endometriosis treated with chronic progesterone therapy presented with a visual deficit and was found to have multiple meningiomas, which regressed after cessation of exogenous progesterone. Conclusion A history of chronic hormone therapy should be included when evaluating patients diagnosed with meningiomas, particularly at a younger age and with multiple meningiomas. Cessation of exogenous progesterone resulting in regression of meningiomas suggests a direct action of progesterone on growth. Future studies are warranted to better elucidate this relationship.

Pituitary society expert Delphi consensus: operative workflow in endoscopic transsphenoidal pituitary adenoma resection.

PURPOSE: Surgical workflow analysis seeks to systematically break down operations into hierarchal components. It facilitates education, training, and understanding of surgical variations. There are known educational demands and variations in surgical practice in endoscopic transsphenoidal approaches to pituitary adenomas. Through an iterative consensus process, we generated a surgical workflow reflective of contemporary surgical practice. METHODS: A mixed-methods consensus process composed of a literature review and iterative Delphi surveys was carried out within the Pituitary Society. Each round of the survey was repeated until data saturation and > 90% consensus was reached. RESULTS: There was a 100% response rate and no attrition across both Delphi rounds. Eighteen international expert panel members participated. An extensive workflow of 4 phases (nasal, sphenoid, sellar and closure) and 40 steps, with associated technical errors and adverse events, were agreed upon by 100% of panel members across rounds. Both core and case-specific or surgeon-specific variations in operative steps were captured. CONCLUSIONS: Through an international expert panel consensus, a workflow for the performance of endoscopic transsphenoidal pituitary adenoma resection has been generated. This workflow captures a wide range of contemporary operative practice. The agreed "core" steps will serve as a foundation for education, training, assessment and technological development (e.g. models and simulators). The "optional" steps highlight areas of heterogeneity of practice that will benefit from further research (e.g. methods of skull base repair). Further adjustments could be made to increase applicability around the world.

In a model of SAH-induced neurogenic fever, BAT thermogenesis is mediated by erythrocytes and blocked by agonism of adenosine A1 receptors.

Neurogenic fever (NF) after subarachnoid hemorrhage (SAH) is a major cause of morbidity that is associated with poor outcomes and prolonged stay in the neurointensive care unit (NICU). Though SAH is a much more common cause of fever than sepsis in the NICU, it is often a diagnosis of exclusion, requiring significant effort to rule out an infectious source. NF does not respond to standard anti-pyretic medications such as COX inhibitors, and lack of good medical therapy has led to the introduction of external cooling systems that have their own associated problems. In a rodent model of SAH, we measured the effects of injecting whole blood, blood plasma, or erythrocytes on the sympathetic nerve activity to brown adipose tissue and on febrile thermogenesis. We demonstrate that following SAH the acute activation of brown adipose tissue leading to NF, is not dependent on PGE2, that subarachnoid space injection of whole blood or erythrocytes, but not plasma alone, is sufficient to trigger brown adipose tissue thermogenesis, and that activation of adenosine A1 receptors in the CNS can block the brown adipose tissue thermogenic component contributing to NF after SAH. These findings point to a distinct thermogenic mechanism for generating NF, compared to those due to infectious causes, and will hopefully lead to new therapies.

Cerebrospinal Fluid Hypovolemia: A Case Report of a Red Herring.

Mild intracranial hypotension can lead to classically recognizable symptoms such as positional headaches, nausea, vomiting, and occasionally blurred vision. Less commonly, severe cerebrospinal fluid (CSF) hypovolemia can lead to a life-threatening condition that mimics intracranial hypertension, including transtentorial herniation and subsequent rapid neurologic decline. In this report we present a unique case of severe intracranial hypotension from a thoracic tumor resection that led to symptoms initially mistaken for intracranial hypertension, however ultimately correctly diagnosed as severe CSF hypovolemia that improved with dural repair. Additionally, we describe a rare angiography finding associated with CSF hypovolemia, kinking of the basilar artery. Here we report a 47-year-old female with neurofibromatosis Type 2 found to have a T3 intradural extramedullary tumor. She initially presented with urinary incontinence and gait/balance difficulty. She underwent thoracic laminectomies at T3 and T4 for the excision of the lesion. She was discharged on postoperative day 4. On postoperative day 9, she was noted to have nausea, vomiting, and decreased consciousness. Head computed tomography (CT) demonstrated acute downward herniation. She was transferred to our institution from a community facility obtunded and was intubated for airway protection. She was placed in the Trendelenburg position with immediate improvement, and declined every time her head was raised. Angiogram showed significant kinking of her basilar artery. A CT myelogram revealed a CSF leak from her recent thoracic surgery. She underwent exploration of her thoracic wound, and a ventral durotomy was repaired. Following this, she began to tolerate the head of bed elevations and recovered back to her neurologic baseline. A postoperative head CT angiography obtained before discharge showed improvement of her basilar kink. Mild intracranial hypotension is a common finding in patients who undergo procedures that enter the CSF space. Severe intracranial hypotension can easily be missed diagnosed as the signs on the exam are similar to patients with signs of intracranial hypertension. It is of paramount importance that the clinician recognizes brain sag, as the treatment algorithms are vastly different from that of intracranial hypertension leading to transtentorial herniation.

Changing Hands: A Rising Role of the Tumor Surgeon in Teaching Sylvian Fissure Dissection.

OBJECTIVE: The landscape of microneurosurgery has changed considerably over the past 2 decades, with a decline in indications for open surgery on cerebrovascular pathology and ever-increasing indications for open resection of brain tumors. This study investigated how these trends in case volume affected residents' training experiences in microsurgery and, specifically, Sylvian fissure dissection. METHODS: Resident case logs were reviewed, identifying open cerebrovascular operations and craniotomies for tumor. Operations involving Sylvian fissure dissection were identified through operative reports. Changes in case number by resident were plotted over time, and linear regression was applied. RESULTS: Among 23 chief residents, 3045 operations were identified, 1071 of which were for cerebrovascular pathology and 1974 for tumor. Open cerebrovascular experience decreased (P < 0.0001) while tumor volume remained unchanged (P = 0.221). The number of Sylvian fissure dissections per resident did not change over time overall (P = 0.583) or within cerebrovascular operations (P = 0.071). The number of Sylvian fissure dissections in tumor operations increased (P = 0.004). This effect was predominated by an increase in intraaxial tumors approached via Sylvian fissure dissection (P = 0.003). The proportion of Sylvian fissure dissections in tumor surgery increased from 15% in 2009 to 34% by 2019 (P = 0.003). CONCLUSIONS: Residents are seeing an increasing proportion of their Sylvian fissure dissection experience during tumor operations. The distribution of this experience will continue to evolve as surgical indications change but suggests a growing role for tumor surgeons in resident training in microsurgery.

Cystic appearance on magnetic resonance imaging in bihormonal growth hormone and prolactin tumors in acromegaly.

PURPOSE: To investigate demographic, imaging and laboratory characteristics, and treatment outcomes of acromegaly patients who have bihormonal (BA) growth hormone (GH) and prolactin (PRL) immunoreactive adenomas compared to patients who have densely granulated GH adenomas (DGA) and sparsely granulated GH adenomas (SGA). METHODS: Retrospective review of single-center surgically treated acromegaly patients; pathology was analyzed by a single neuropathologist using 2017 WHO criteria. Preoperative magnetic resonance imaging was assessed to evaluate tumor size, cystic component, invasion and T2 signal intensity. RESULTS: Seventy-seven patients; 19 BA (9 mammosomatotroph and 10 mixed GH and PRL adenomas) were compared with 30 DGA, and 28 SGA. Patients with BA were older than SGA (49.6 vs 38.5 years, p = 0.035), had a higher IGF-1 index (3.3 vs 2.3, p = 0.040) and tumors were less frequently invasive (15.8% vs 57.1%, p = 0.005). BA more frequently had a cystic component on MRI than both SGA and DGA (52.6% vs 14.3%, and 22%, p = 0.005 and 0.033, respectively). When all histological types were combined, biochemical remission postoperatively was more common in non-cystic than cystic tumors (50% vs 22.5%, p = 0.042). Somatostatin receptor ligand response rate was 66.7%, 90.9% and 37.5% in BA, DGA and SGA patients, respectively (p = 0.053). CONCLUSION: Imaging characteristics are an increasingly important adenoma behavior determinant. An adenoma cystic component may suggest that a GH adenoma is a BA. Cystic tumors exhibited lower rates of surgical remission in this series; therefore, optimized individual patient treatment is needed, as patients could be candidates for primary medical treatment.

Pituitary society guidance: pituitary disease management and patient care recommendations during the COVID-19 pandemic-an international perspective.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the viral strain that has caused the coronavirus disease 2019 (COVID-19) pandemic, has presented healthcare systems around the world with an unprecedented challenge. In locations with significant rates of viral transmission, social distancing measures and enforced 'lockdowns' are the new 'norm' as governments try to prevent healthcare services from being overwhelmed. However, with these measures have come important challenges for the delivery of existing services for other diseases and conditions. The clinical care of patients with pituitary disorders typically involves a multidisciplinary team, working in concert to deliver timely, often complex, disease investigation and management, including pituitary surgery. COVID-19 has brought about major disruption to such services, limiting access to care and opportunities for testing (both laboratory and radiological), and dramatically reducing the ability to safely undertake transsphenoidal surgery. In the absence of clinical trials to guide management of patients with pituitary disease during the COVID-19 pandemic, herein the Professional Education Committee of the Pituitary Society proposes guidance for continued safe management and care of this population.

Hypercoagulability in Cushing Syndrome, Prevalence of Thrombotic Events: A Large, Single-Center, Retrospective Study.

BACKGROUND: The risk of Cushing syndrome (CS) patients experiencing a thrombotic event (TE) is significantly higher (odds ratio; OR 18%) than that of the general population. However, there are currently no anticoagulation guidelines. METHODS: A retrospective, single-center, longitudinal study of patients undergoing all types of treatment-surgical (pituitary, unilateral, and bilateral adrenalectomy) and medical treatment-was undertaken. TEs were recorded at any point up until last patient follow-up; myocardial infarction (MI), deep venous thrombosis (DVT), and pulmonary embolism (PE) or stroke. Patients' doses and complications of anticoagulation were recorded. RESULTS: Included were 208 patients; a total of 165 (79.3%) were women, and mean age at presentation was 44 ±â€…14.7 years. Thirty-nine (18.2%) patients had a TE; extremity DVT (38%), cerebrovascular accident (27%), MI (21%), and PE (14%). Of 56 TEs, 27 (48%) were arterial and 29 (52%) were venous. Patients who underwent bilateral adrenalectomy (BLA) had an odds ratio of 3.74 (95% CI 1.69-8.27) of developing a TE. Of patients with TEs, 40.5% experienced the event within the first 60 days after surgery. Baseline 24-hour urinary free cortisol levels did not differ in patients with or without TE after BLA. Of 197 patients who underwent surgery, 50 (25.38%) received anticoagulation after surgery, with 2% having bleeding complications. CONCLUSIONS: The risk of TEs in patients with CS was approximately 20%. Many patients had more than 1 event, with higher risk 30 to 60 days postoperatively. The optimal prophylactic anticoagulation duration is unknown, but most likely needs to continue up to 60 days postoperatively, particularly after BLA.

Dural Arteriovenous Fistula Presenting as Trigeminal Neuralgia: 2 Case Reports and Review of the Literature.

BACKGROUND: Dural arteriovenous fistulae (dAVFs) can sporadically compress the root entry zone of the trigeminal nerve or the Gasserian ganglion and therefore be a rare cause of isolated or complicated trigeminal neuralgia (TN). CASE DESCRIPTION: We describe 2 cases of TN related to dAVF treated similarly with transarterial embolization but with divergent outcomes. Further, we completed a comprehensive literature review of previously reported cases to date. A sparse but growing literature with regards to this specific and rare but salient cause of TN was noted. The type of dAVF most commonly found to cause TN was that of a tentorial nidus, a lesion generally accepted to be at high risk of hemorrhage and in need of urgent treatment. This warrants imaging for new TN presentations to ensure that a dangerous lesion does not represent the underlying cause, especially when the TN symptoms are comorbid with other symptoms such as a bruit. Treatments pursued span the range of open surgery, endovascular treatment, and radiosurgery with great success in treating both the TN symptoms, as well as the rupture risk of the dAVF itself in most cases. Indeed, endovascular approaches are becoming more widely employed for these cases over time, often resolving the abnormality on first treatment attempt. Other cases reach resolution after employing a combination of treatment modalities. CONCLUSIONS: This work highlights that dAVFs, particularly the tentorial type, are capable of causing TN symptomatically identical to that of other etiologies and that treatment of the dAVF itself is often sufficient.

Arteriovenous Malformation Presenting as Symptomatic, Enlarging and Contrast-Enhancing Mass 12 Years After Being Treated with Embolization and Radiotherapy.

BACKGROUND: Gross total resection of arteriovenous malformations (AVMs) of the central nervous system confirmed by formal angiography is accepted as a cure for patients. In some cases, this may not be possible. Even though in these cases other treatment modalities such as endovascular embolization and radiotherapy can be used, long-term follow-up is lacking in the literature. CASE DESCRIPTION: Here we report a case of a 57-year-old woman with history of a right-sided parieto-occipital/periatrial AVM, initially treated with a combination of endovascular embolization and radiotherapy. CONCLUSIONS: The patient subsequently presented (12 years later) with a symptomatic, enlarging, contrast-enhancing mass at the same location that was angiographically occult but ultimately proven to be an AVM on a background of reactive changes on pathology.

Medial axis segmentation of cranial nerves using shape statistics-aware discrete deformable models.

PURPOSE: We propose a segmentation methodology for brainstem cranial nerves using statistical shape model (SSM)-based deformable 3D contours from T2 MR images. METHODS: We create shape models for ten pairs of cranial nerves. High-resolution T2 MR images are segmented for nerve centerline using a 1-Simplex discrete deformable 3D contour model. These segmented centerlines comprise training datasets for the shape model. Point correspondence for the training dataset is performed using an entropy-based energy minimization framework applied to particles located on the centerline curve. The shape information is incorporated into the 1-Simplex model by introducing a shape-based internal force, making the deformation stable against low resolution and image artifacts. RESULTS: The proposed method is validated through extensive experiments using both synthetic and patient MRI data. The robustness and stability of the proposed method are experimented using synthetic datasets. SSMs are constructed independently for ten pairs (CNIII-CNXII) of brainstem cranial nerves using ten non-pathological image datasets of the brainstem. The constructed ten SSMs are assessed in terms of compactness, specificity and generality. In order to quantify the error distances between segmented results and ground truths, two metrics are used: mean absolute shape distance (MASD) and Hausdorff distance (HD). MASD error using the proposed shape model is 0.19 ± 0.13 (mean ± std. deviation) mm and HD is 0.21 mm which are sub-voxel accuracy given the input image resolution. CONCLUSION: This paper described a probabilistic digital atlas of the ten brainstem-attached cranial nerve pairs by incorporating a statistical shape model with the 1-Simplex deformable contour. The integration of shape information as a priori knowledge results in robust and accurate centerline segmentations from even low-resolution MRI data, which is essential in neurosurgical planning and simulations for accurate and robust 3D patient-specific models of critical tissues including cranial nerves.

High prevalence of adrenal insufficiency at diagnosis and headache recovery in surgically resected Rathke's cleft cysts-a large retrospective single center study.

BACKGROUND: Rathke's cleft cysts (RCC) are lesions that arise from Rathke's pouch. Though frequently incidental, resulting symptoms in a minority of cases are indicators for surgical resection, which may prove beneficial. OBJECTIVE: To characterize a cohort of surgically-resected RCC cases at Oregon Health & Science University; tabulate associated hormonal imbalances and symptoms, possible symptom reversal with surgery, determine recurrence risk; identify predictors of recurrence and headache improvement. METHOD: Electronic records of all RCC resected cases (from 2006-2016; 11 years) were retrospectively reviewed. Patients had been evaluated by one neuroendocrinologist using a uniform protocol. RESULTS: A pathological RCC diagnosis was established in 73 of 814 (9%) surgical pituitary cases. The RCC cohort was 77% (n = 56/73) female, mean age was 39.5 ± 14.9 years at first surgery, and at presentation headache was reported in 88% and visual defects/diplopia in 18% of patients. Initial RCC maximum diameter was 1.3 ± 0.7 cm. The most frequent hormonal deficit was cortisol; 24% of patients had a new adrenal insufficiency (AI) diagnosis, however, 36% also had AI at 3 months post-operatively. Mean follow up was 4.0 ± 4.5 years. Two-thirds of patients (41/62) had headache improvement 3 months post-operatively. Post-operative imaging revealed no residual cyst in 58% (38/65). In those patients with no residual RCC, 29% had recurrence and 71% had long lasting cure. From the 42% (27/65) of patients with residual cyst on post-operative imaging; 59% (16/27) remained stable, 26% (7/27) progressed and 15% (4/27) regressed. CONCLUSION: Symptomatic RCC present mostly in women, with a high proportion reporting headaches. Prevalence of AI at diagnosis is high. Surgery may not achieve adrenal axis recovery, but renders a high percentage of headache improvement. Approximately 25% of RCC will recur by 4 years postoperatively. Clinicians should cautiously screen patients with symptomatic RCC, regardless of lesion size for AI.

Surgical Parameters for Minimally Invasive Trans-Eustachian Tube CSF Leak Repair: A Cadaveric Study and Literature Review.

BACKGROUND: Cerebrospinal fluid rhinorrhea from a lateral skull base defect refractory to spontaneous healing and/or conservative management is most commonly managed via open surgery. Approach for repair is dictated by location of the defect, which may require surgical exploration. The final common pathway is the eustachian tube (ET). Endoscopic ET obliteration via endonasal and lateral approaches is under development. Whereas ET anatomy has been studied, surgical landmarks have not been previously described or quantified. We aimed to define surgical parameters of specific utility to endoscopic ET obliteration. METHODS: A literature review was performed of known ET anatomic parameters. Next, using a combination of endoscopic and open techniques in cadavers, we cannulated the intact ET and dissected its posterior component to define the major curvature position of the ET, defined as the genu, and quantified the relative distances through the ET lumen. The genu was targeted as a major obstacle encountered when cannulating the ET from the nasopharynx. RESULTS: Among 10 ETs, we found an average distance of 23 ± 5 mm from the nasopharynx to the ET genu, distance of 24 ± 3 mm from the genu to the anterior aspect of the tympanic membrane and total ET length of 47 ± 4 mm. CONCLUSIONS: Although membranous and petrous components of the ET are important to its function, the genu may be a more useful surgical landmark. Basic surgical parameters for endoscopic ET obliteration are defined.