Cavalcanti DD, Preul MC, Kalani MYS, Spetzler RF. Microsurgical anatomy of safe entry zones to the brainstem. J Neurosurg. 2016;124(5):1359–1376. doi:10.3171/2015.4.JNS141945.
In this image rich paper, the authors examined 13 safe entry zones on the brainstem (previously described in the literature) and used cadaveric dissections to evaluate the main surgical approaches currently employed to manage intrinsic brainstem lesions. Through dissection images of these approaches, they demonstrate what can be seen on the brainstem through each of these surgical corridors and delineate the safe entry zones provided by each approach. The approaches described include three midbrain regions (anterior mesencephalic zone, lateral mesencephalic sulcus, intercollicular region), 6 pontine zones (peritrigeminal zone, supratrigeminal zone, lateral pontine zone, supracollicular zone, infracollicular zone, median sulcus of the fourth ventricle), and 4 medullary zones (anterolateral and posterior median sulci of the medulla, olivary zone, and lateral medullary zone). In addition to the surface anatomy, the paper describes the general surgical approaches to the regions, including Orbitozygomatic, Subtemporal, Subtemporal Transtentorial, Anterior Petrosectomy, Suboccipital Telovelar, Median Supracerebellar Infratentorial, Extreme Lateral Supracerebellar Infratentorial, Retrosigmoid, Far Lateral, and Retrolabyrinthine.
13 illustrations and 2 tables.
Close to all a Neuroradiologist needs to know about surgical approaches to the brainstem, and then some.
Drazin D, Nuño M, Patil CG, Yan K, Liu JC, Acosta FL. Emergency room resource utilization by patients with low-back pain. J Neurosurg Spine. 2016;24(5):686–693. doi:10.3171/2015.7.SPINE14133.
The authors conducted a retrospective analysis of patients with LBP discharged from hospitals according to the Nationwide Inpatient Sample (NIS) between 1998 and 2007. A majority (65%) of patients discharged from hospitals in the US from 1998 to 2007 with a primary diagnosis of LBP were admitted through the ER, with more patients being admitted via this route each year (183,151 patients). These patients were less likely to be discharged directly home compared with patients with LBP who were not admitted through the ER. Uninsured and African American patients with LBP were more likely to be admitted through the ER than their counterparts, as were patients with more preexisting health problems. Patients with LBP at the highest income levels were more likely to be admitted through hospital ERs. Specifically, they found that the lowest-income patients in the NIS database were actually less likely to be admitted to the hospital through the ER. The reason for this is unknown, but the authors speculate that this may be the result of these patients actually leaving the ER without ever being seen by a physician (perhaps as a result of overcrowding of ERs in those areas that serve a high proportion of extremely low-income patients). They conclude that socioeconomic factors may play a role in the utilization of ER resources by patients with LBP.
Lots of conjecture, but some very interesting data points.
Finger EC. Frontotemporal dementias. Contin Lifelong Learn Neurol. 2016;22(2):464–489. doi:10.1212/CON.0000000000000300.
Frontotemporal dementia is second only to Alzheimer disease as a cause of early-onset neurodegenerative dementia (before age 65). FTD refers to one of several clinical subtypes including behavioral variant of FTD (bvFTD), semantic variant primary progressive aphasia (PPA), nonfluent agrammatic variant PPA, and FTD associated with motor neuron disease (FTD-MND). FTD related disorders include two tau associated neurodegenerative diseases, corticobasal syndrome (CBS) and progressive supranuclear palsy (PSP). The most common type of FTD (50% of all FTD) behavioral variant of FTD is defined by the gradual onset and progression of changes in behavior, including disinhibition, loss of empathy, apathy, and may include hyperorality and perseverative or compulsive behaviors. Atrophy or hypometabolism of the right frontal or right temporal lobe is the hallmark neuroimaging finding in patients with behavioral variant of FTD. Atrophy of the dominant anterior temporal pole is the hallmark finding in semantic variant PPA. Approximately 40% of FTD is associated with an autosomal dominant pattern of inheritance. Mutations in approximately eight genes have been linked to FTD, accounting for 50% of familial FTD, with mutations in progranulin (GRN), chromosome 9 open reading frame 72 (C9ORF72), and microtubule-associated protein tau (MAPT) accounting for the majority of cases.
Lewy body related pathology is observed in dementia with Lewy bodies (DLB), idiopathic PD, multiple system atrophy (MSA), and DLB and the dementia that arises in PD (ie, Parkinson disease dementia [PDD]). The clinical features of dementia with Lewy bodies and Parkinson disease dementia are similar and include hallucinations, cognitive fluctuations, and dementia in the setting of the extrapyramidal motor impairments known as parkinsonism. DLB and PDD are common, clinically similar syndromes that share characteristic neuropathologic changes, including deposition of alpha synuclein in Lewy bodies and neurites and loss of tegmental dopamine cell populations and basal forebrain cholinergic populations, often with a variable degree of coexisting Alzheimer pathology.
Gomperts SN. Lewy Body Dementias. Contin Lifelong Learn Neurol. 2016;22(2, Dementia):435–463. doi:10.1212/CON.0000000000000309.
Lewy body related pathology is observed in dementia with Lewy bodies (DLB), idiopathic PD, multiple system atrophy (MSA), and DLB and the dementia that arises in PD (ie, Parkinson disease dementia [PDD]). The clinical features of dementia with Lewy bodies and Parkinson disease dementia are similar and include hallucinations, cognitive fluctuations, and dementia in the setting of the extrapyramidal motor impairments known as parkinsonism. DLB and PDD are common, clinically similar syndromes that share characteristic neuropathologic changes, including deposition of alpha synuclein in Lewy bodies and neurites and loss of tegmental dopamine cell populations and basal forebrain cholinergic populations, often with a variable degree of coexisting Alzheimer pathology.
Freedman BA, Malone DG, Rasmussen PA, Cage JM, Benzel EC. Surferʼs Myelopathy. Neurosurgery. 2016;78(5):602–611. doi:10.1227/NEU.0000000000001089.
Sixty-four cases of surfer’s myelopathy have been reported to date. This atraumatic thoracic/conus medullaris myelopathy with only a 42% neurological recovery rate almost uniformly affects young, healthy, novice surfers who have no pre-existent spinal disease. Symptoms usually start with back pain and rapidly progress to complete or incomplete myelopathy. T2 magnetic resonance images show increased signal in the central spinal cord within 24 to 72 hours. They postulate that the prolonged prone hyperextension that is typical of novice surfers is a mechanical event that is capable of instigating a vascular cord insult. Hyperextension can distract the radicular vessels, which can compromise flow. Alternatively, or in concert, the altered venous return that occurs from lying prone for prolonged periods of time on a surfboard can contribute to vascular insufficiency.
3 Figures and 2 tables.
Haussen DC, Jadhav A, Jovin T, et al. Endovascular Management vs Intravenous Thrombolysis for Acute Stroke Secondary to Carotid Artery Dissection. Neurosurgery. 2016;78(5):709–716. doi:10.1227/NEU.0000000000001072.
This is a retrospective analysis of 21 patients with consecutive high-grade steno-occlusive carotid dissection with National Institutes of Health Stroke Scale >5 and <12 hours of last seen normal from 2 tertiary centers. A systematic review for studies on IVT in the setting of CAD via PubMed was performed for comparison. Mean time from last-known-normal to puncture was 4.8 hours and procedure length 1.8 hours. Stents were used in 52% of cases, and reperfusion achieved in 95%. They conclude that interventional management of acute stroke in high-grade steno-occlusive carotid dissection is feasible and safe and leads to high rates of reperfusion and good outcome.
The authors note that the order in which tandem lesions are approached remains a controversial topic, with the general trend to address the dissection first and then the intracranial circulation. They believe that considering the high efficacy of stent retrievers that only require a small microcatheter for deployment, cerebral reperfusion as a first step should be the primary procedural approach. Once intracranial reperfusion is achieved, they more often pursue a conservative approach and do not stent the CAD.
Jones AL, Cascino GD. Evidence on Use of Neuroimaging for Surgical Treatment of Temporal Lobe Epilepsy: A Systematic Review. JAMA Neurol. 2016;73(4):464–70. doi:10.1001/jamaneurol.2015.4996.
In this systematic review, the authors evaluated the diagnostic yield of MRI, PET, and SPECT in patients with drug-resistant focal seizures who had a surgically remediable epileptic syndrome. Of the 27 studies evaluated (3163 patients), 7 showed the outcome was more favorable in patients with MRI-identified hippocampal atrophy indicating mesial temporal sclerosis. They conclude that hippocampal formation atrophy identified on MRI was a strong predictor of a seizure-free outcome; with conflicting results regarding the importance of PET and SPECT for predicting outcome. There is a paucity of evidence-based medical studies in evaluating the usefulness of PET and SPECT in selecting patients for epilepsy surgery. The high diagnostic yield of PET has been confirmed in temporal lobe epilepsy. Patients with focal PET hypometabolism and an unremarkable MRI have an operative outcome similar to that of patients with MRI-identified MTS.
Lee W-J, Lee S-T, Byun J-I, et al. Rituximab treatment for autoimmune limbic encephalitis in an institutional cohort. Neurology. 2016;86(18):1683–1691. doi:10.1212/WNL.0000000000002635.
Rituximab is a monoclonal antibody against CD20-positive B cells, which induces B-cell depletion. The authors evaluated 80 patients with autoimmune limbic encephalitis who were treated with rituximab as a second-line immunotherapy from the Korea Autoimmune Synaptic and Paraneoplastic Encephalitis Registry and reviewed 81 patients without rituximab as a control. First-line immunotherapy consisted of corticosteroids, IV immunoglobulins, and plasmapheresis. Functional improvement occurred more frequently in the rituximab group compared to the control group. In the rituximab group, 37.5% patients had synaptic autoantibodies, 18.8% had paraneoplastic autoantibodies, and 43.8% were antibody-negative. The effect of rituximab was the same regardless of autoantibody status. This study provides Class IV evidence that rituximab improves modified Rankin Scale scores for patients with autoimmune limbic encephalitis who fail first-line therapy.
3 figures (which are graphs), 2 tables.
Vollmer TL, McCarthy M. Autoimmune encephalitis: A more treatable tragedy if diagnosed early. Neurology. 2016;86(18):1655–1656. doi:10.1212/WNL.0000000000002641
Excellent editorial accompanying the Lee article on autoimmune encephalitis that highlights some interesting data:
-20,000 cases of encephalitis occur in the United States annually.
-Anti-NMDA receptor antibodies that bind to a cell surface expressed antigen are now recognized as one of the most common causes of autoimmune encephalitis.
-From 2007-2011, the California Encephalitis Project reported 32 cases of anti-NMDA receptor antibody mediated encephalitis, more numerous than cases of herpes simplex virus, varicella-zoster virus, and West Nile virus encephalitis combined.
-There are currently 17 autoantibodies targeting the CNS identified to date which can be involved in autoimmune encephalitis.
