A modified retromaxillary approach to the infratemporal fossa: three case studies.

The infratemporal fossa (ITF) is an anatomically complex region with multiple neural and vascular structures entering and exiting through foramina in the skull base. The main obstacles to approaching the ITF are the zygomatic arch, the parotid gland, the facial nerve, and the ascending ramus AND condylar head of the mandible. Different surgical approaches to the ITF exist and the best approach should provide optimal visibility, minimal impairment of temporomandibular joint function, and preservation of motor and sensory nerve integrity. This report describes a modified Obwegeser retromaxillary approach to access lesions within the ITF. A multidisciplinary team was involved, which included an oral and maxillofacial surgery team, a neurosurgery team, and an otolaryngology team. Three patients with large skull base lesions, including an aneurysmal bone cyst, a giant cell tumor of the bone, and an invasive melanoma, underwent resection using this approach and were followed postoperatively. Excellent exposure of the floor of the middle cranial fossa and ITF was achieved with this approach. Functional status remained unchanged with respect to mastication, speech, swallowing, and cosmesis. Given the severity of the patients' conditions and extent of involvement of the skull base, outcomes were favorable, with minimal morbidity. This experience suggests that this approach provides safe access to an anatomically complex region and lessens challenges associated with more conventional approaches.

Familial syndromes associated with intracranial tumours: a review.

BACKGROUND: Most cancers of the central nervous system (CNS) occur sporadically in the absence of any known underlying familial disorder or multi-systemic syndrome. Several syndromes are associated with CNS malignancies, however, and their recognition has significant implications for patient management and prognosis. Patients with syndrome-associated CNS malignancies often have multiple tumours (either confined to one region or distributed throughout the body), with similar or different histology. OBJECTIVE: This review examines syndromes that are strongly associated with CNS cancers: the phakomatosis syndromes, familial syndromes such as Li-Fraumeni and familial polyposis syndromes and dyschondroplasia.

Using Single-Photon Emission Computerized Tomography on Patients With Positive Quantitative Electroencephalogram to Evaluate Chronic Mild Traumatic Brain Injury With Persistent Symptoms.

Background: Following mild traumatic brain injury (mTBI), also known as concussion, many patients with chronic symptoms (>3 months post injury) receive conventional imaging such as computed tomography (CT) or magnetic resonance imaging (MRI). However, these modalities often do not show changes after mTBI. We studied the benefit of triaging patients with ongoing symptoms >3 months post injury by quantitative electroencephalography (qEEG) and then completing a brain single positron emission computed tomography (SPECT) to aid in diagnosis and early detection of brain changes. Methods: We conducted a retrospective case review of 30 outpatients with mTBI. The patients were assessed by a neurologist, consented, and received a qEEG, and if the qEEG was positive, they consented and received a brain SPECT scan. The cases and diagnostic tools were collectively reviewed by a multidisciplinary group of physicians in biweekly team meetings including neurology, nuclear medicine, psychiatry, neuropsychiatry, general practice psychotherapy, neuro-ophthalmology, and chiropractic providers. The team noted the cause of injury, post injury symptoms, relevant past medical history, physical examination findings, and diagnoses, and commented on patients' SPECT scans. We then analyzed the SPECT scans quantitatively using the 3D-SSP software. Results: All the patients had cerebral perfusion abnormalities demonstrated by SPECT that were mostly undetectable by conventional imaging (CT/MRI). Perfusion changes were localized primarily in the cerebral cortex, basal ganglia, and cingulate cortex, and correlated with the patients' symptoms and examination findings. Qualitative and quantitative analyses yielded similar results. Most commonly, the patients experienced persistent headache, memory loss, concentration difficulties, depression, and cognitive impairment post mTBI. Because of their symptoms, most of the patients were unable to return to their previous employment and activity level. Conclusion: Our findings outline the physical basis of neurological and psychiatric symptoms experienced by patients with mTBI. Increased detection of mTBI can lead to development of improved targeted treatments for mTBI and its various sequelae.

Coronal synostosis syndrome (Muenke syndrome): the value of genetic testing versus clinical diagnosis.

BACKGROUND: Muenke syndrome is a fibroblast growth factor receptor 3 (FGFR-3)-associated coronal craniosynostosis syndrome, which was first described in 1997. CASE: We report an infant girl who was born to a 29-year-old primapara at 38 weeks' gestation. When evaluated at 3 days old, physical examination revealed a high forehead with frontal bossing, upturned nose, arched palate, shallow midface structures, and heavily ridged coronal sutures bilaterally. Clinically, the infant seemed to be neurologically normal. Skull radiographs and computed tomography confirmed the presence of bilateral coronal synostosis, with patency of all other sutures. Family history was remarkable, in that the infant's father, paternal grandmother, and a paternal cousin demonstrated subtle craniofacial features, which had not been previously identified. Mutation analysis of FGFR-3 revealed a missense mutation in exon 6, c.749 C>G, with a resultant amino acid change from proline to arginine at codon 250 (P250R), in keeping with Muenke syndrome (Am J Hum Genet 1997;60:555-564). The mutation was subsequently identified in her father, suggesting variable expression in this family, as he had only mild midfacial flattening. At 9 months of age, our patient underwent anterior cranial expansion, correction of orbital hypertelorism, intracranial orbital osteotomies, and advancement of the frontal bandeau. She tolerated the procedure well and has done well postoperatively. CONCLUSIONS: We report the case of an infant with Muenke syndrome, with evidence of variable expressivity within the paternal family. The pertinent literature, in which only 2 prior Canadian cases were identified, is reviewed.

Craniosynostosis involving the squamous temporal sutures: a rare and possibly underreported etiology for cranial vault asymmetry.

Craniosynostosis is a condition in which 1 or more cranial sutures fuse prematurely, often secondary to a fibroblast growth factor receptor (FGFR) mutation, typically involving FGFR2 or FGFR3. This mutation may occur sporadically or in the setting of a genetic syndrome and typically presents within the first few days of life or in early infancy. Most commonly, the sagittal and coronal sutures are involved, although involvement of the lambdoidal and/or metopic sutures is not uncommon. Surgical correction is undertaken both for cosmetic purposes and to relieve raised intracranial pressure, both of which can be severe, depending on the sutures involved. We report on 2 children who presented in their first year of life with synostosis involving: in one instance, a single squamous temporal suture, and in the other, both squamous temporal sutures. The initial presentation and clinical courses of these 2 patients are highly distinct from one another, although both ultimately did quite well after extensive cranial remodeling. To the best of our knowledge, only a handful of patients with squamous synostosis have been reported in the medical literature.

Magnetic Particle Imaging in Neurosurgery.

BACKGROUND: Magnetic particle imaging (MPI) is a novel radiation-free tomographic imaging method that provides a background-free, signal attenuation-free, direct quantification of the spatial distribution of superparamagnetic iron-oxide nanoparticles (SPIONs) with high temporal resolution (milliseconds), high spatial resolution (<1 mm), and extreme sensitivity (µmol). The technique is based on nonlinear magnetization of the SPIONs when exposed to an oscillating magnetic field. MPI was first described in 2001. Since then, the technique has been applied to experimental imaging of diseases affecting different organs in the human body. The aim of this paper is to review the potential applications of MPI in the field of neurosurgery. METHODS: A nonsystematic review of the existing literature on the use of MPI in neurosurgical diseases was performed. RESULTS: MPI has been used for the detection of locoregional invasion of brain tumors, tracking, and monitoring the viability of neural stem cells implanted for neuroregenerative purposes, diagnosis of cerebral ischemia, and diagnosis and morphofunctional assessment of brain aneurysms. CONCLUSIONS: MPI is at a preclinical stage. In the future, human-sized MPI scanners, along with the optimal toxicity profile of SPIONs will allow diagnostic applications in neurosurgical diseases.

Stereotactic Radiosurgery in Large Intracranial Meningiomas: A Systematic Review.

Gross total resection of large intracranial meningiomas (LIMs) can be challenging and cause significant morbidity and mortality. The aim of this systematic review is to determine the clinical effectiveness and safety of stereotactic radiosurgery (SRS) either as primary or adjuvant therapy for LIMs with tumors ≥2.5 cm in maximum dimension (tumor volume ≥8.1 cm3). A total of 452 tumors in 496 patients (350 female [69.3%] and 146 male [30.6%]) with median age 60 years (48-65 years) were included. The median tumor volume at the time of diagnosis was 16.7 cm3 (10-53.3 cm3). The tumors typically were located in the skull base (77.2%), whereas only 14.6% were in the supratentorial space. The median follow-up after SRS was 54 months (18-90 months). In total, 87.8% of patients were treated with single-session (SS) Gamma Knife radiosurgery (GKS), whereas the remaining 12.1% patients received non-SS GKS. Of 452 LIMs assessed for clinical response, 45.1% showed improvement and 15.7% deteriorated after SRS. Radiographic tumor control at last follow-up (2-7.5 years) ranged from 84% to 100%. Overall, radiation-induced toxicity occurred in 23% of patients, with the most common adverse effect being cranial nerve neuropathy (5.5%) and peritumoral edema (5.3%). Subgroup analysis revealed that there is 2-fold greater likelihood of improvement in clinical symptoms in patients with non-SS GKS than SS GKS (odds ratio 2.47; 95% confidence interval 1.38-4.44; P = 0.002). SRS is safe and effective in the treatment of LIMs as primary or adjuvant treatment. Further prospective studies are required to validate our results.

Long-term follow up data on difficult to treat intracranial arteriovenous malformations treated with the CyberKnife.

INTRODUCTION: The CyberKnife, a frameless, robotic, stereotactic device, has been developed to radiosurgically treat arteriovenous malformations (AVMs). While most AVMs are obliterated within two-to-three years, a subset remain recalcitrant; long-term data on these difficult to treat AVMs are limited in the neurosurgical literature. MATERIALS AND METHODS: A retrospective analysis of all patients who underwent CyberKnife treatment for intracranial AVMs at a single U.S. institution between 2002 and 2012, whose AVMs had failed to obliterate within 48 months or longer from the treatment start date, were eligible for inclusion. RESULTS: Eleven patients (9 AVMs; 7 males, 2 females) were followed for an average of 85.2 months (range 56.2-119.4). The median lesion size was 3.5 cm (range: 2.8-8.0 cm) and median Spetzler-Martin grade was 3 (range: 2-5). All AVMs were treated with one radiation dose (median prescribed dose was 18.0 Gy; median Dmax: 23.7 Gy). Six (66.7%) were obliterated in a median time of 84 months (range: 52-94 months), while 3 (33.3%) remained active after a median of 90.8 months (range 69.7-119.4). Transient, post-radiosurgery adverse radiation effects occurred in 5 (55.6%) cases. One (11.1%) patient had an acute hemorrhage from the AVM after radiosurgery. Four (44.4%) patients underwent repeat radiosurgery and/or embolization. Three of these lesions eventually obliterated, while 1 did not. CONCLUSION: The median time to obliteration was 84 months. Two-thirds of AVMs which persisted for over 4 years following initial radiosurgery treatment eventually obliterated. Transient post-radiosurgery adverse effects were common; delayed hemorrhages were rare in our case series.

Gold Nanoparticles for Brain Tumor Imaging: A Systematic Review.

BACKGROUND: Demarcation of malignant brain tumor boundaries is critical to achieve complete resection and to improve patient survival. Contrast-enhanced brain magnetic resonance imaging (MRI) is the gold standard for diagnosis and pre-surgical planning, despite limitations of gadolinium (Gd)-based contrast agents to depict tumor margins. Recently, solid metal-based nanoparticles (NPs) have shown potential as diagnostic probes for brain tumors. Gold nanoparticles (GNPs) emerged among those, because of their unique physical and chemical properties and biocompatibility. The aim of the present study is to review the application of GNPs for in vitro and in vivo brain tumor diagnosis. METHODS: We performed a PubMed search of reports exploring the application of GNPs in the diagnosis of brain tumors in biological models including cells, animals, primates, and humans. The search words were "gold" AND "NP" AND "brain tumor." Two reviewers performed eligibility assessment independently in an unblinded standardized manner. The following data were extracted from each paper: first author, year of publication, animal/cellular model, GNP geometry, GNP size, GNP coating [i.e., polyethylene glycol (PEG) and Gd], blood-brain barrier (BBB) crossing aids, imaging modalities, and therapeutic agents conjugated to the GNPs. RESULTS: The PubMed search provided 100 items. A total of 16 studies, published between the 2011 and 2017, were included in our review. No studies on humans were found. Thirteen studies were conducted in vivo on rodent models. The most common shape was a nanosphere (12 studies). The size of GNPs ranged between 20 and 120 nm. In eight studies, the GNPs were covered in PEG. The BBB penetration was increased by surface molecules (nine studies) or by means of external energy sources (in two studies). The most commonly used imaging modalities were MRI (four studies), surface-enhanced Raman scattering (three studies), and fluorescent microscopy (three studies). In two studies, the GNPs were conjugated with therapeutic agents. CONCLUSION: Experimental studies demonstrated that GNPs might be versatile, persistent, and safe contrast agents for multimodality imaging, thus enhancing the tumor edges pre-, intra-, and post-operatively improving microscopic precision. The diagnostic GNPs might also be used for multiple therapeutic approaches, namely as "theranostic" NPs.

Quantitative analysis of the safety and efficacy of microvascular decompression for patients with trigeminal neuralgia above and below 65 years of age.

For medically-refractory trigeminal neuralgia (TN), microvascular decompression (MVD) is the first-line treatment, and has demonstrated the greatest efficacy and durability. However, due to potential surgical complications, a bias may exist against performing MVD in elderly patients. We sought to determine through a quantitative analysis whether MVD in the elderly is a safe and effective procedure for TN. We completed a Pubmed/SCOPUS literature search up to 12/2016 for eligible studies on MVD for TN. Only research articles with age stratification of results were included. In this quantitative analysis, we analyzed the data for the six articles identified in the literature comparing MVD for a group of patients ≥65 years with an elderly group <65 years. A total of 1483 were included. 455 patients were ≥65 years (mean 70.8 years, range 65-89 years) and 1028 patients were <65 years (mean 53.4 years, range 19-64 years). Composite mean follow-up time was 51.6 months for the elderly group, and 55.1 months for the young group. Following MVD, each group had 1 mortality (p = 0.43). There were 21 serious morbidities in the elderly group (4.62%) and 32 in the young group (3.11%) (p = 0.11). In addition, 15 patients (1.46%) in the elderly group and 24 patients (1.62%) in the young group experienced a cerebrospinal fluid leak (p = 0.23). TN recurrence rates 9.23% in the young group and 13.33% in the elderly group (p = 0.070). In conclusion, for properly-selected surgical candidates, MVD should not be ruled out on the basis of age ≥65 years.

Evidence for Use of Teriparatide in Spinal Fusion Surgery in Osteoporotic Patients.

BACKGROUND: Osteoporosis is defined as bone mineral density. METHODS: A PubMed literature review was performed to review preclinical and clinical evidence for the use of teriparatide in osteoporotic patients undergoing spine fusion surgery. RESULTS: Preclinical studies in animal models show that teriparatide increases spinal fusion rates. Early clinical studies show that teriparatide both increases spinal fusion rates and decreases hardware loosening in the setting of postmenopausal osteoporosis. CONCLUSION: Ongoing additional trials will help formulate preoperative screening recommendations, determine the optimal duration of preoperative and postoperative teriparatide treatment, and investigate its utility in men.

Papillary thyroid carcinoma metastasizing to anaplastic meningioma: an unusual case of tumor-to-tumor metastasis.

Tumor-to-tumor metastasis is a relatively uncommon entity, whereby the so-called 'recipient' tumor is involved by another biologically unrelated 'donor' tumor. Intracranially, meningioma (WHO grade 1) is the most common recipient tumor, while breast and lung cancers are the most common donor tumors. We present an unusual case of intracranial tumor-to-tumor metastasis involving papillary thyroid carcinoma (PTC) believed to have metastasized to an anaplastic meningioma (WHO grade 3). The patient is a 64-year-old female with a history of PTC, whose neuroimaging, performed as part of her staging workup, revealed a right parietal scalp lesion. The lesion was resected to reveal metastatic PTC with spindle cell component believed to represent sarcomatoid differentiation. Follow-up neuroimaging 2 months later revealed regrowth of the lesion under the previous craniotomy site. PET scan showed increased uptake in this area consistent with metastasis. Resection of this lesion revealed primarily features of an anaplastic meningioma. The combination of pathologic findings from both resections in conjunction with findings from the PET scan led to the suggestion that the PTC had metastasized into the anaplastic meningioma. To the authors' knowledge, this is the first example in the literature of a donor tumor metastasizing to a high-grade recipient tumor.

Magnetic resonance perfusion image features uncover an angiogenic subgroup of glioblastoma patients with poor survival and better response to antiangiogenic treatment.

BACKGROUND: In previous clinical trials, antiangiogenic therapies such as bevacizumab did not show efficacy in patients with newly diagnosed glioblastoma (GBM). This may be a result of the heterogeneity of GBM, which has a variety of imaging-based phenotypes and gene expression patterns. In this study, we sought to identify a phenotypic subtype of GBM patients who have distinct tumor-image features and molecular activities and who may benefit from antiangiogenic therapies. METHODS: Quantitative image features characterizing subregions of tumors and the whole tumor were extracted from preoperative and pretherapy perfusion magnetic resonance (MR) images of 117 GBM patients in 2 independent cohorts. Unsupervised consensus clustering was performed to identify robust clusters of GBM in each cohort. Cox survival and gene set enrichment analyses were conducted to characterize the clinical significance and molecular pathway activities of the clusters. The differential treatment efficacy of antiangiogenic therapy between the clusters was evaluated. RESULTS: A subgroup of patients with elevated perfusion features was identified and was significantly associated with poor patient survival after accounting for other clinical covariates (P values <.01; hazard ratios > 3) consistently found in both cohorts. Angiogenesis and hypoxia pathways were enriched in this subgroup of patients, suggesting the potential efficacy of antiangiogenic therapy. Patients of the angiogenic subgroups pooled from both cohorts, who had chemotherapy information available, had significantly longer survival when treated with antiangiogenic therapy (log-rank P=.022). CONCLUSIONS: Our findings suggest that an angiogenic subtype of GBM patients may benefit from antiangiogenic therapy with improved overall survival.

Stereotactic radiosurgery for metastasis to the craniovertebral junction preserves spine stability and offers symptomatic relief.

OBJECT Metastatic disease to the craniovertebral junction (CVJ) is rare but presents unique management challenges. To date, studies on using stereotactic radiosurgery (SRS) for CVJ metastases have been limited to case reports and small case series. The aim of this analysis was to evaluate the utility of SRS in the management of these secondary lesions. METHODS Clinical and radiological information from the charts of 25 patients with metastatic disease of the CVJ who were treated with SRS between 2005 and 2013 at the Stanford CyberKnife Center were retrospectively reviewed. RESULTS Seven male and 18 female patients with a median age of 58 years (range 34-94 years) were identified. The most common primary tumors were breast cancer (n = 5) and non-small cell lung cancer (n = 5), and the most frequent symptom was neck pain (n = 17). The average tumor volume treated was 15.9 cm3 (range 0.16-54.1 cm3), with a mean marginal radiation dose of 20.3 Gy (range 15-25.5 Gy). The median follow-up was 18 months (range 1-81 months), though 1 patient was lost to follow-up. SRS provided radiographic tumor stability in over 80% of patients, offered pain alleviation in nearly two-thirds of patients, and produced no serious complications. Moreover, SRS preserved spinal stability in all but 1 patient, in whom pre-SRS stability was established. There was no evidence of radiation toxicity in the patient population. Median survival was 28 months (range 2-81 months), with survival of 13.3% at 5 years. CONCLUSIONS In the absence of unstable pathological fracture and spinal cord compression, metastatic tumors of the CVJ can be safely and effectively treated with SRS. This treatment option offers palliative pain relief and can halt tumor progression with only a low risk of complications or spinal instability.

Kinematic analysis following implantation of the PRESTIGE LP.

BACKGROUND: The clinical success of cervical arthroplasty hinges on the ability to preserve or improve the biomechanics of the functional spinal unit. The purpose of this study was to conduct a radiologic assessment of kinematic parameters preimplantation and postimplantation of the PRESTIGE LP Cervical Disc System (Medtronic, Memphis, Tennessee). METHODS: A total of 120 radiographs of 20 patients following single-level implantation of the PRESTIGE LP were retrospectively reviewed. Static and dynamic radiologic assessments were performed before surgery and at 1 year postoperation. Kinematic parameters including range of motion (ROM), horizontal translation, center of rotation (COR X, Y), anterior disc height and posterior disc height, and disc angle and shell angle were assessed for each spinal level using quantitative motion analysis software. Clinical outcomes were assessed using the short form health survey physical component scores and mental component scores. RESULTS: The mean physical component scores and mental component scores of the short form health survey (SF-36) improved significantly following surgery. At 1 year postoperation, ROM, translation, and COR X were preserved. The COR Y shifted superiorly from 3.17 ± 2.08 mm preoperation to 0.98 ± 2.23 mm postoperation (P < .001). The anterior disc height and posterior disc height were significantly increased following surgery (3.97 ± 1.01 to 4.78 ± 1.11 mm and 3.04 ± 0.69 to 3.66 ± 0.61 mm, respectively; P < .01). The preoperative disc angle was 3.32° ± 2.92° and the postoperative shell angle was 1.11° ± 4.29°, with a mean change of -2.22° ± 4.63° (P < .05). CONCLUSIONS: The PRESTIGE LP maintained preoperative ROM, translation, and COR X values. The postoperative COR Y value changed significantly by shifting superiorly, accompanied by an increase in DH. There was a loss of lordosis at the level of surgery, with the PRESTIGE LP endplates having an almost parallel endplate configuration.

Brainstem cavernoma hemorrhage during pregnancy in a 15-year-old: description of a unique neurosurgical approach.

Cavernous haemangiomas, or cavernous malformations, have been reported during pregnancy, most of which have been either supratentorial or spinal lesions. We encountered a 15-year old pregnant patient with a rapidly progressive and haemorrhagic brainstem cavernous haemangioma. The case presented here describes the history and findings of this patient, as well as the less-commonly utilized technique we used to access the floor of the fourth ventricle via occipital craniotomy for complete macroscopic resection of this lesion, resulting in the gradual return of most of her neurological deficits.

A rare case of atlantooccipital dissociation in the context of occipitalization of the atlas, with a 2-year follow-up: case report.

Atlantooccipital dislocation (AOD) is a rare and often fatal injury. In cases of survival, residual deficits are severe and often include cranial nerve palsy, quadriplegia, or respiratory issues. Occipitalization is defined as partial or complete congenital fusion of the occiput to the atlas and is exceptionally rare. The authors present a rare case of AOD superimposed on a congenital occipitalization of the atlas. This 39-year-old man had AOD following a motor vehicle collision. On examination, his overall motor score on the American Spinal Injury Association scale was 5/100, and his rectal tone was absent. Computed tomography demonstrated AOD in an area of occipitalization. Magnetic resonance imaging revealed ligamentous injury leading to C1-2 instability. Intervention included occipital cervical instrumentation fusion from the occiput to C-3. Six months postoperatively, imaging revealed fusion of the graft and consolidation of the fractured occipitalization. At the 2-year follow-up, the patient's strength was 3/5 for wrist extension and handgrip on the right side and full strength in the rest of the myotomes. Bladder and bowel function was also normalized. A high-velocity collision led to disruption of the atlantooccipital ligaments and fracture of the occipitalized lateral masses in this patient. Internal fixation and fusion led to good fusion postoperatively. Occipitalization probably led to abnormal joint mechanics at the C1-occiput junction, which might have altered the amount of force required to fracture the occipitalization and produce AOD. This difference may partially account for the favorable neurological outcome in the featured patient compared with traditional cases of AOD.

Supine digital subtraction myelography for the demonstration of a dorsal cerebrospinal fluid leak in a patient with spontaneous intracranial hypotension: a technical note.

A patient with spontaneous intracranial hypotension due to a spinal cerebrospinal fluid (CSF) leak required localization of the leakage site prior to surgical management. Conventional, computed tomography and prone digital subtraction myelography failed to localize the dural tear, which was postulated to be dorsally located. We present here a digital subtraction myelographic approach to accurately localize a dorsal site of CSF leakage by injecting iodinated contrast via a lumbar drain with the patient in the supine position.

Central pontine and extrapontine myelinolysis in children: a review of 76 patients.

This study aimed to identify the causes and contributing factors, neurologic presentation, and outcomes of central pontine and extrapontine myelinolysis and to examine any trends in the presentation and course of these disorders over the past 50 years. Seventy-six pediatric cases were identified in the literature. Age, sex, decade of diagnosis, neurologic presentation, outcome, and attributed causes were extracted. The results showed that the diagnosis, course, and outcomes of central pontine and extrapontine myelinolysis clearly have changed over the past few decades. Early cases generally were diagnosed at autopsy as opposed to computed tomography or magnetic resonance imaging more recently. Ninety-four percent of cases prior to 1990 and only 7% of cases from 1990 onward resulted in patient mortality. The decade in which the case was reported was the strongest predictor of outcome (P < .001), followed by sodium dysregulation (P = .045) and dehydration (P = .07).