Jonathan Rick

Factors Associated With Pre- and Postoperative Seizures in 1033 Patients Undergoing Supratentorial Meningioma Resection

BACKGROUND Risk factors for pre- and postoperative seizures in supratentorial meningiomas are understudied compared to other brain tumors. OBJECTIVE To report seizure frequency and identify factors associated with pre- and postoperative seizures in a large single-center population study of patients undergoing resection of supratentorial meningioma. METHODS Retrospective chart review of 1033 subjects undergoing resection of supratentorial meningioma at the authors institution (1991-2014). Multivariate regression was used to identify variables significantly associated with pre- and postoperative seizures. RESULTS Preoperative seizures occurred in 234 (22.7%) subjects. At 5 years postoperative, probability of seizure freedom was 89.9% among subjects without preoperative seizures and 62.2% with preoperative seizures. Multivariate analysis identified the following predictors of preoperative seizures: presence of  ≥1 cm peritumoral edema (odds ratio [OR]: 4.45, 2.55-8.50), nonskull base tumor location (OR: 2.13, 1.26-3.67), greater age (OR per unit increase: 1.03, 1.01-1.05), while presenting symptom of headache (OR: 0.50, 0.29-0.84) or cranial nerve deficit (OR: 0.36, 0.17-0.71) decreased odds of preoperative seizures. Postoperative seizures after discharge were associated with preoperative seizures (OR: 5.70, 2.57-13.13), in-hospital seizure (OR: 4.31, 1.28-13.67), and among patients without preoperative seizure, occurrence of medical or surgical complications (OR 3.39, 1.09-9.48). Perioperative anti-epileptic drug use was not associated with decreased incidence of postoperative seizures. CONCLUSIONS Nonskull base supratentorial meningiomas with surrounding edema have the highest risk for preoperative seizure. Long-term follow-up showing persistent seizures in meningioma patients with preoperative seizures raises the possibility that these patients may benefit from electrocorticographic mapping of adjacent cortex and resection of noneloquent, epileptically active cortex.

Cross-activating c-Met/β1 integrin complex drives metastasis and invasive resistance in cancer

Significance Invasion is a major cause of cancer mortality, as exemplified by metastatic spread of peripheral malignancies or local intracranial invasion of glioblastoma. While individual mediators of invasion are identified, functional or structural interactions between these mediators remain undefined. We identified a structural cross-activating c-Met/β1 integrin complex that promotes breast cancer metastases and invasive resistance of glioblastoma to the antiangiogenic therapy bevacizumab. We show that tumor cells adapt to their microenvironmental stressors by usurping c-Met and β1 integrin, with c-Met displacing α5 integrin from β1 integrin to form a c-Met/β1 complex with far greater fibronectin affinity than α5β1 integrin. These findings challenge conventional thinking about integrin–ligand interactions and define a molecular target for disrupting metastases or invasive oncologic resistance. The molecular underpinnings of invasion, a hallmark of cancer, have been defined in terms of individual mediators but crucial interactions between these mediators remain undefined. In xenograft models and patient specimens, we identified a c-Met/β1 integrin complex that formed during significant invasive oncologic processes: breast cancer metastases and glioblastoma invasive resistance to antiangiogenic VEGF neutralizing antibody, bevacizumab. Inducing c-Met/β1 complex formation through an engineered inducible heterodimerization system promoted features crucial to overcoming stressors during metastases or antiangiogenic therapy: migration in the primary site, survival under hypoxia, and extravasation out of circulation. c-Met/β1 complex formation was up-regulated by hypoxia, while VEGF binding VEGFR2 sequestered c-Met and β1 integrin, preventing their binding. Complex formation promoted ligand-independent receptor activation, with integrin-linked kinase phosphorylating c-Met and crystallography revealing the c-Met/β1 complex to maintain the high-affinity β1 integrin conformation. Site-directed mutagenesis verified the necessity for c-Met/β1 binding of amino acids predicted by crystallography to mediate their extracellular interaction. Far-Western blotting and sequential immunoprecipitation revealed that c-Met displaced α5 integrin from β1 integrin, creating a complex with much greater affinity for fibronectin (FN) than α5β1. Thus, tumor cells adapt to microenvironmental stressors induced by metastases or bevacizumab by coopting receptors, which normally promote both cell migration modes: chemotaxis, movement toward concentrations of environmental chemoattractants, and haptotaxis, movement controlled by the relative strengths of peripheral adhesions. Tumor cells then redirect these receptors away from their conventional binding partners, forming a powerful structural c-Met/β1 complex whose ligand-independent cross-activation and robust affinity for FN drive invasive oncologic processes.

Improved Survival with Decreased Wait Time to Surgery in Glioblastoma Patients Presenting with Seizure

BACKGROUND: Preoperative seizure is reported to confer favorable prognosis in glioblastoma patients, but studies to date have not investigated how broadly applicable seizure is as a prognostic factor. OBJECTIVE: To investigate if prompter surgical intervention affects the relationship between preoperative seizure and prognosis in glioblastoma patients, focusing on the development of tumor growth and/or additional preoperative symptoms after seizure. METHODS: Retrospective analysis of 443 patients (mean age = 60.2; 60% male) undergoing first glioblastoma resection at our institution (2005‐2011). RESULTS: Preoperative seizure(s) occurred in 28% of patients (n = 124), of which 63 (51%) had only seizure at presentation. Patients experiencing seizure as their only preoperative symptom (“seizure‐only”; n = 45) survived over twice as long as patients who presented with seizure and then later developed additional preoperative symptoms (n = 18; “other symptoms postseizure”; 26.8 vs 10.2 months, P < .001) and patients without preoperative seizure (“no seizure”; 26.8 vs 13.1 months, P < .001). Multivariate stepwise analysis revealed preoperative seizures only (hazard ratio 0.54 [0.37‐0.75]; P < .001) to be independently associated with increased survival. Longer wait time from presentation (ie, diagnostic magnetic resonance imaging) to surgery was a risk factor for developing additional symptoms. Eleven “other symptoms postseizure” patients (69%) vs 6 of the “seizure‐only” patients (15%) had wait times >45 days (P < .001). CONCLUSION: Seizure as the only preoperative symptom independently improved survival, however, when patients developed additional preoperative symptoms, typically due to surgical delay, no prognostic benefit was observed. Prompt diagnosis and neurosurgical intervention is warranted in patients with seizures without other preoperative symptoms to preserve their favorable prognosis.

Tumor treating fields: a new approach to glioblastoma therapy

Glioblastoma is an aggressive brain malignancy with poor outcomes. Current standard of care involves surgery, radiotherapy and chemotherapy. Even with optimal treatment, 5-year survival rates are low. Many patients are unable to tolerate the considerable side effects that therapy involves and suffer from low quality of life. Anti-mitotic tumor treating fields have shown potential in treating glioblastoma with data suggesting that they prolong disease-free survival and overall survival. Novocure has marketed a device that generates these fields via externally placed electrodes. Incorporation of electric field therapy into GBM treatment has been somewhat slow, due to concerns about cost, practicality of its usage from a patient perspective, and hesitation of the medical and scientific community to embrace its unconventional mechanism. However, clinical trials have demonstrated this therapy has relatively minor side effects and high patient compliance. In this review, we explore the current state of this technology and discuss the benefits and limitations of tumor treating fields.

Temporal profile of care following mild traumatic brain injury: predictors of hospital admission, follow-up referral and six-month outcome

ABSTRACT Objective: To investigate the clinical management and medical follow-up of patients with mild traumatic brain injury (mTBI) presenting to emergency departments (EDs). Methods: Overall, 168 adult patients with mTBI from the prospective, multicentre Transforming Research and Clinical Knowledge in TBI (TRACK-TBI) Pilot study with Glasgow Coma Scale (GCS) 13–15, no polytrauma and alive at six months were included. Predictors for hospital admission, three-month follow-up referral and six-month functional disability (Glasgow Outcome Scale-Extended (GOSE) ≤ 6) were analysed using multivariable regression. Results: Overall, 48% were admitted to hospital, 22% received three-month referral and 27% reported six-month functional disability. Intracranial pathology on ED head computed tomography (multivariable odds ratio (OR) = 81.08, 95% confidence interval (CI) [10.28–639.36]) and amnesia (>30-minutes: OR = 5.27 [1.75–15.87]; unknown duration: OR = 4.43 [1.26–15.62]) predicted hospital admission. Older age (per-year OR = 1.03 [1.01–1.05]) predicted three-month referral, while part-time/unemployment predicted lack of referral (OR = 0.17 [0.06–0.50]). GCS < 15 (OR = 2.46 [1.05–5.78]) and prior history of seizures (OR = 3.62 [1.21–10.89]) predicted six-month functional disability, while increased education (per-year OR = 0.86 [0.76–0.97]) was protective. Conclusions: Clinical factors modulate triage to admission, while demographic/socioeconomic elements modulate follow-up care acquisition; six-month functional disability associates with both clinical and demographic/socioeconomic variables. Improving triage to acute and outpatient care requires further investigation to optimize resource allocation and outcome after mTBI. ClinicalTrials.gov registration: NCT01565551

Patients cured of acromegaly do not experience improvement of their skull deformities.

PurposeAcromegaly is a rare disease that is associated with many co-morbidities. This condition also causes progressive deformity of the skull which includes frontal bossing and cranial thickening. Surgical and/or medical management can cure this condition in many patients, but it is not understood if patients cured of acromegaly experience regression of their skull deformities.MethodsWe performed a retrospective analysis on patients treated at our dedicated pituitary center from 2009 to 2014. We looked at all MRI images taken during the treatment of these patients and recorded measurements on eight skull dimensions. We then analyzed these measurements for changes over time.Results29 patients underwent curative treatment for acromegaly within our timeframe. The mean age for this population was 45.0 years old (range 19–70) and 55.2 % (n = 16) were female. All of these patients were treated with a transsphenoidal resection for a somatotropic pituitary adenoma. 9 (31.1%) of these patients required further medical therapy to be cured. We found statically significant variation in the coronal width of the sella turcica after therapy, which is likely attributable to changes from transsphenoidal surgery. None of the other dimensions had significant variation over time after cure.ConclusionPatients cured of acromegaly should not expect natural regression of their skull deformities. Our study suggests that both frontal bossing and cranial thickening do not return to normal after cure.

Update on critical care for acute spinal cord injury in the setting of polytrauma

Traumatic spinal cord injury (SCI) often occurs in patients with concurrent traumatic injuries in other body systems. These patients with polytrauma pose unique challenges to clinicians. The current review evaluates existing guidelines and updates the evidence for prehospital transport, immobilization, initial resuscitation, critical care, hemodynamic stability, diagnostic imaging, surgical techniques, and timing appropriate for the patient with SCI who has multisystem trauma. Initial management should be systematic, with focus on spinal immobilization, timely transport, and optimizing perfusion to the spinal cord. There is general evidence for the maintenance of mean arterial pressure of > 85 mm Hg during immediate and acute care to optimize neurological outcome; however, the selection of vasopressor type and duration should be judicious, with considerations for level of injury and risks of increased cardiogenic complications in the elderly. Level II recommendations exist for early decompression, and additional time points of neurological assessment within the first 24 hours and during acute care are warranted to determine the temporality of benefits attributable to early surgery. Venous thromboembolism prophylaxis using low-molecular-weight heparin is recommended by current guidelines for SCI. For these patients, titration of tidal volumes is important to balance the association of earlier weaning off the ventilator, with its risk of atelectasis, against the risk for lung damage from mechanical overinflation that can occur with prolonged ventilation. Careful evaluation of infection risk is a priority following multisystem trauma for patients with relative immunosuppression or compromise. Although patients with polytrauma may experience longer rehabilitation courses, long-term neurological recovery is generally comparable to that in patients with isolated SCI after controlling for demographics. Bowel and bladder disorders are common following SCI, significantly reduce quality of life, and constitute a focus of targeted therapies. Emerging biomarkers including glial fibrillary acidic protein, S100β, and microRNAs for traumatic SCIs are presented. Systematic management approaches to minimize sources of secondary injury are discussed, and areas requiring further research, implementation, and validation are identified.

Reduction of shunt dependency rates following aneurysmal subarachnoid hemorrhage by tandem fenestration of the lamina terminalis and membrane of Liliequist during microsurgical aneurysm repair

OBJECTIVEShunt-dependent hydrocephalus is an important cause of morbidity following aneurysmal subarachnoid hemorrhage (aSAH) in excess of 20% of cases. Hydrocephalus leads to prolonged hospital and ICU stays, well as to repeated surgical interventions, readmissions, and complications associated with ventriculoperitoneal (VP) shunts, including shunt failure and infection. Whether variations in surgical technique at the time of aneurysm treatment may modify rates of shunt dependency remains a matter of debate. Here, the authors report on their experience with tandem fenestration of the lamina terminalis (LT) and membrane of Liliequist (MoL) at the time of open microsurgical repair of the ruptured aneurysm.METHODSThe authors conducted a retrospective review of 663 consecutive patients with aSAH treated from 2005 to 2015 by open microsurgery via a pterional or orbitozygomatic craniotomy by the senior author (M.T.L.). Data collected from review of the electronic medical record included age, Hunt and Hess grade, Fisher grade, need for an external ventricular drain, and opening pressure. Patients were stratified into those undergoing no fenestration and those undergoing tandem fenestration of the LT and MoL at the time of surgical repair. Outcome variables, including VP shunt placement and timing of shunt placement, were recorded and statistically analyzed.RESULTSIn total, shunt-dependent hydrocephalus was observed in 15.8% of patients undergoing open surgical repair following aSAH. Tandem microsurgical fenestration of the LT and MoL was associated with a statistically significant reduction in shunt dependency (17.9% vs 3.2%, p < 0.01). This effect was confirmed with multivariate analysis of collected variables (multivariate OR 0.09, 95% CI 0.03-0.30). Number-needed-to-treat analysis demonstrated that tandem fenestration was required in approximately 6.8 patients to prevent a single VP shunt placement. A statistically significant prolongation in days to VP shunt surgery was also observed in patients treated with tandem fenestration (26.6 ± 19.4 days vs 54.0 ± 36.5 days, p < 0.05).CONCLUSIONSTandem fenestration of the LT and MoL at the time of open microsurgical clipping and/or bypass to secure ruptured anterior and posterior circulation aneurysms is associated with reductions in shunt-dependent hydrocephalus following aSAH. Future prospective randomized multicenter studies are needed to confirm this result.

A novel xenograft model reveals invasive mesenchymal transition and ineffective angiogenic response during the evolution of resistance to anti-angiogenic therapy

Bevacizumab treatment of glioblastoma is limited by transient responses and acquired resistance. Because of the lengthy duration of treatment that can precede resistance in patients, in order to study changes underlying the evolution of bevacizumab resistance, we created a novel multigenerational xenograft model of acquired bevacizumab resistance. Glioblastoma xenografts were treated with bevacizumab or IgG, and the fastest growing tumor re-implanted into new mice, generating paired isogeneic responsive or resistant multigenerational xenografts. Microarray analysis revealed significant overexpression across generations of the mesenchymal subtype gene signature, paralleling results from patient bevacizumab-resistant glioblastomas (BRGs) that exhibited increasing mesenchymal gene expression correlating with increased bevacizumab treatment duration. Key mesenchymal markers, including YKL-40, CD44, SERPINE1, and TIMP1 were upregulated across generations, with altered morphology, increased invasiveness, and increased neurosphere formation confirmed in later xenograft generations. Interestingly, YKL-40 levels were elevated in serum of patients with bevacizumab-resistant vs. bevacizumab-naïve glioblastomas. Finally, despite upregulation of VEGF-independent pro-angiogenic genes across xenograft generations, immunostaining revealed increased hypoxia and decreased vessel density with increasing generation of treatment, mirroring our findings in patient BRGs and suggesting tumor growth despite effective devascularization caused by VEGF blockade. Besides identifying novel targets for preventing the evolution of resistance and offering a xenograft model for testing resistance inhibitors, our work suggests YKL-40 as a blood biomarker of bevacizumab resistance worthy of further evaluation.

Functional brain mapping: overview of techniques and their application to neurosurgery

Functional brain mapping (FBM) is an integral part of contemporary neurosurgery. It is crucial for safe and optimal resection of brain lesions like gliomas. The eloquent regions of the cortex like motor, somatosensory, Wernicke’s, and Broca are usually mapped, either preoperatively or intraoperatively. Since its birth in the nineteenth century, FBM has witnessed immense modernization, radical refinements, and the introduction of novel techniques, most of which are non-invasive. Direct electrical stimulation of the cortex, despite its high invasiveness, remains the technique of choice. Non-invasive techniques like fMRI and magnetoencephalography allow us the convenience of multiple mappings with minimal discomfort to the patients. They are quick, easy to do, and allow thorough study. Different modalities are now being combined to yield better delineations like fMRI and diffusion tensor imaging. This article reviews the physical principles, applications, merits, shortcomings, and latest developments of nine FBM techniques. Other than neurosurgical operations, these techniques have also been applied to studies of stroke, Alzheimer’s, and cognition. There are strong indications that the future of brain mapping shall see the non-invasive techniques playing a more dominant role as they become more sensitive and accurate due to advances in physics, refined algorithms, and subsequent validation against invasive techniques.