Please check out the accompanying podcast of this blog post (also known as “Annotated Bibliography”):
1. Benarroch EE. The amygdala: Functional organization and involvement in neurologic disorders. Neurology. 2015;84(3):313–324.
This detailed review of the functional organization of the amygdala includes intrinsic and extrinsic connections, physiology and its function in humans. Examples of clinical correlations include Kluver-Bucy syndrome, lipoid proteinosis (Urbach-Wiethe disease) and a variety of other neurometabolic diseases. Kluver-Bucy is characterized by visual agnosia, oral exploration of objects, excessive visual attentiveness, and altered sexual behavior. Lipoid proteinosis is an autosomal recessive disorder with a mutations in the ‘extracellular matrix protein 1’ gene. fMRI studies have shown that the amygdala is responsive to fearful facial expressions. This response does not even require an intact visual cortex. An fMRI study in a patient with cortical blindness showed amygdala activation in response to faces directed towards the viewer (Burra N. et al., Amygdala activation for eye contact despite complete cortical blindness. J Neurosci 2013;33:10483–10489).
2. Chalouhi N, Zanaty M, Whiting A, et al. Treatment of Ruptured Intracranial Aneurysms With the Pipeline Embolization Device. Neurosurgery. 2015;76(2):165–172. doi:10.1227/NEU.0000000000000586.
The authors present a case series of 20 patients with ruptured aneurysms who were treated with the pipeline embolization device (PED). Mean duration from hemorrhage to placement of the PED was 7 days. Adjunctive coil placement was used in 30%. The one complication that occurred was a fatal intraoperative aneurysm dome rupture during adjunctive coil deployment. Follow-up angiography at a mean of 5 months showed 100% occlusion in 80% of patients, and incomplete occlusion in 20%. They conclude that treatment of ruptured aneurysms with the PED has a low complication rate and high occlusion rate, and may be safe and effective option for aneurysms difficult to treat with conventional methods. 5 Figures.
The patients in this study were loaded with aspirin and clopidogrel or received an infusion of tirofiban (Aggrastat) intraoperatively. This discussion gives a nice summary of the controversies and difficulties treating acutely ruptured aneurysm patients with dual antiplatelet therapy. They also give their general guidelines for who and what to treat, such as use with wide-neck or blister aneurysms, pseudoaneurysms, and giant or dissecting aneurysms. They also favor Hunt and Hess grades III or less, since these patients less frequently require invasive procedures that might increase morbidity in the face of dual antiplatelet therapy.
3. Flanagan EP, Weinshenker BG, Krecke KN, et al. Short Myelitis Lesions in Aquaporin-4-IgG–Positive Neuromyelitis Optica Spectrum Disorders. JAMA Neurol. 2015;72(1):81. doi:10.1001/jamaneurol.2014.2137.
Longitudinally extensive transverse myelitis that is defined MR as extending 3 or more vertebral segments, is the most specific radiological finding supporting neuromyelitis optica (NMO) diagnosis in adults and should prompt physicians to test for aquaporin-4-IgG. Short transverse myelitis (STM) lesions defined by MR as not extending 3 vertebral segments is much more common in MS than in NMO. The authors wanted to determine the frequency of short lesions at the initial myelitis manifestation of NMO and to compare the demographic, clinical, and radiological characteristics of AQP4-IgG seropositive and seronegative STM lesions. Patients at the Mayo Clinic who were identified as AQP4-IgG positive from 1996 to 2014 were included. 25 patients who were AQP4-IgG seropositive with an initial STM were 14% of initial myelitis episodes among patients with NMO spectrum disorder. Delay to diagnosis and treatment was greater when initial lesions were short. Subsequent myelitis episodes were longitudinally extensive in 92%. They conclude that short transverse myelitis does not exclude consideration of AQP4-IgG testing. 3 Figures.
In the Discussion, the authors point out the clinical importance of making the distinction between MS and NMO, since therapies favored in MS may exacerbate NMO (such as interferon-beta) (Kim SH, et al., Does interferon beta treatment exacerbate neuromyelitis optica spectrum disorder? Mult Scler. 2012;18(10):1480-1483).
4. Gelfand JM, Genrich G, Green AJ, Tihan T, Cree BAC. Encephalitis of Unclear Origin Diagnosed by Brain Biopsy. JAMA Neurol. 2015;72(1):66. doi:10.1001/jamaneurol.2014.2376.
In this retrospective case series, the authors looked at patients with encephalitis diagnosed by brain biopsy from January 1, 1983, through December 31, 2011 (n=58), with an original pathologic diagnosis of “encephalitis, not otherwise specified” (ENOS). In 29 patients where pathological material was still available, additional review led to a more specific diagnosis in 34%. Despite comprehensive review with additional information and studies, 27 patients were still classified at ENOS. The authors conclude that these patients remain a diagnostic challenge, and that current algorithms are of limited value.
The final more specific categorizations or diagnoses were quite varied, and included LGI1 limbic encephalitis, paraneoplastic encephalitis (Ma2 antibodies), gliomatosis cerebri, lymphoma, Listeria, TB, HSV-2, and toxoplasmosis, among others.
5. Buckwalter JA, Tolo VT, O’Keefe RJ. How Do You Know It Is True? Integrity in Research and Publications: AOA Critical Issues. J Bone Jt Surg. 2015;97:e2–e2. doi:10.2106/JBJS.N.00245.
An excellent overview of research integrity, with examples of fabrication, falsification, and plagiarism in the recent literature. If you want to publish, or have published, you should read this article.
6. Kim H, Abla AA, Nelson J, et al. Validation of the Supplemented Spetzler-Martin Grading System for Brain Arteriovenous Malformations in a Multicenter Cohort of 1009 Surgical Patients. Neurosurgery. 2015;76(1):25–33. doi:10.1227/NEU.0000000000000556.
The supplementary grading system (Supp) for brain arteriovenous malformations (AVMs) was introduced in 2010 for improving preoperative risk prediction and selecting patients for surgery, and awards points for the ABCs of AVMs: 1) patient age, 2) bleeding or hemorrhagic presentation, 3) AVM compactness, in an analogous fashion to the scoring of the Spetzler-Martin (SM) system. Patients <20 years are assigned 1 point; 20-40 years given 2 points; and >40 years given 3 points. Unruptured AVMs are given 1 point, and with a rupture given 0 points. Diffuse AVMs are given 1 point, and compact AVMs 0 points. In this study, data collected from 1009 AVM patients who underwent AVM resection were used to compare the predictive powers of SM and SM-Supp grades. The SM-Supp system performed better than SM system alone: area under the receiver-operating characteristics curve (AUROC) = 0.75. They conclude that study validates the predictive accuracy of the SM-Supp system in a multicenter cohort. A SM-Supp grade of 6 is a cutoff or boundary for AVM operability.
The Discussion section is particularly useful for the explanation of the individual elements of the Supp system. Age – younger patients better tolerate surgery, and have more neural plasticity. Hemorrhage provides a better surgical corridor and ready made parenchymal dissection (hence the 0 points awarded). Compact AVMs allow for separation from adjacent parenchyma and no intermixed brain.
7. Lin N, Brouillard AM, Krishna C, et al. Use of Coils in Conjunction With the Pipeline Embolization Device for Treatment of Intracranial Aneurysms. Neurosurgery. 2015;76(2):142–149. doi:10.1227/NEU.0000000000000579.
This case-controlled study evaluated 29 patients treated with PED + coils and 75 patients treated with PED only. No statistically significant between-group differences were found in terms of age, sex, aneurysm location, medical comorbidities, and length of follow-up. Complete aneurysm occlusion was achieved in a higher proportion of the PED+coils group (93.1% vs 74.7%, P = .03). The rates of neurological complications and favorable outcome were similar. The authors conclude that PED+coils may be a safe and effective treatment for aneurysms with a high risk of rupture. 4 Figures.
In the Discussion section the authors caution against dense packing of the coils when a PED is used, since a dense coil pack could result in mass effect on the PED and cause device thrombosis.
