SciCombinator

Discover the most talked about and latest scientific content & concepts.

Journal: Neurosurgery

202

Pain relief with spinal cord stimulation (SCS) has focused historically on paresthesias overlapping chronically painful areas. A higher level evidence supports the use of SCS in treating leg pain than supports back pain, as it is difficult to achieve adequate paresthesia coverage, and then pain relief, in the low back region. In comparison, 10-kHz high-frequency (HF10) SCS therapy does not rely on intraoperative paresthesia mapping and remains paresthesia-free during therapy.

Concepts: Spinal disc herniation, Pain

152

Currently, only presumptive diagnosis of chronic traumatic encephalopathy (CTE) can be made in living patients. We present a modality that may be instrumental to the definitive diagnosis of CTE in living patients based on brain autopsy confirmation of [F-18]FDDNP-PET findings in an American football player with CTE. [F-18]FDDNP-PET imaging was performed 52 mo before the subject’s death. Relative distribution volume parametric images and binding values were determined for cortical and subcortical regions of interest. Upon death, the brain was examined to identify the topographic distribution of neurodegenerative changes. Correlation between neuropathology and [F-18]FDDNP-PET binding patterns was performed using Spearman rank-order correlation. Mood, behavioral, motor, and cognitive changes were consistent with chronic traumatic myeloencephalopathy with a 22-yr lifetime risk exposure to American football. There were tau, amyloid, and TDP-43 neuropathological substrates in the brain with a differential topographically selective distribution. [F-18]FDDNP-PET binding levels correlated with brain tau deposition (rs = 0.59, P = .02), with highest relative distribution volumes in the parasagittal and paraventricular regions of the brain and the brain stem. No correlation with amyloid or TDP-43 deposition was observed. [F-18]FDDNP-PET signals may be consistent with neuropathological patterns of tau deposition in CTE, involving areas that receive the maximal shearing, angular-rotational acceleration-deceleration forces in American football players, consistent with distinctive and differential topographic vulnerability and selectivity of CTE beyond brain cortices, also involving midbrain and limbic areas. Future studies are warranted to determine whether differential and selective [F-18]FDDNP-PET may be useful in establishing a diagnosis of CTE in at-risk patients.

Concepts: Psychology, Brain, Spearman's rank correlation coefficient, Cognition, Cerebral cortex, Mesencephalon, Autopsy, American football

117

Frameless, non-isocentric irradiation of an extended segment of the trigeminal nerve introduces new concepts in stereotactic radiosurgery for medically resistant trigeminal neuralgia (TN).

Concepts: Neurology, Radiosurgery, Stereotactic surgery, Trigeminal neuralgia

30

When the fourth edition of the Brain Trauma Foundation’s Guidelines for the Management of Severe Traumatic Brain Injury were finalized in late 2016, it was known that the results of the RESCUEicp (Trial of Decompressive Craniectomy for Traumatic Intracranial Hypertension) randomized controlled trial of decompressive craniectomy would be public after the guidelines were released. The guideline authors decided to proceed with publication but to update the decompressive craniectomy recommendations later in the spirit of “living guidelines,” whereby topics are updated more frequently, and between new editions, when important new evidence is published. The update to the decompressive craniectomy chapter presented here integrates the findings of the RESCUEicp study as well as the recently published 12-mo outcome data from the DECRA (Decompressive Craniectomy in Patients With Severe Traumatic Brain Injury) trial. Incorporation of these publications into the body of evidence led to the generation of 3 new level-IIA recommendations; a fourth previously presented level-IIA recommendation remains valid and has been restated. To increase the utility of the recommendations, we added a new section entitled Incorporating the Evidence into Practice. This summary of expert opinion provides important context and addresses key issues for practitioners, which are intended to help the clinician utilize the available evidence and these recommendations. The full guideline can be found at: https://braintrauma.org/guidelines/guidelines-for-the-management-of-severe-tbi-4th-ed#/.

28

: In the past 2 decades, intraoperative navigation technology has changed preoperative and intraoperative strategies and methodology tremendously.

Concepts: Depth perception, Intraoperative monitoring

28

BACKGROUND:: Mesh cages have commonly been used for reconstruction after corpectomy. Recently, expandable cages have become a popular alternative. Regardless of cage type, subsidence is a concern following cage placement. OBJECTIVE:: To assess whether subsidence rates differ between static and expandable cages, and identify independent risk factors for subsidence and extent of subsidence when present. METHODS:: A consecutive population of patients who underwent corpectomy between 2006 and 2009 was identified. Subsidence was assessed via x-ray at 1-month and 1-year follow-ups. In addition to cage type, demographic, medical, and cage-related covariates were recorded. Multivariate models were employed to assess independent associations with rate, odds, and extent of subsidence. RESULTS:: Of 91 patients, 44.0% had expandable and 56.0% had static cage. One-month subsidence rate was 36.3%, and 51.6% at 1 year. Expandable cages were independently associated with higher rates and odds of subsidence compared to static cages. Infection, trauma, and footplate-to-vertebral body endplate ratio of less than 0.5 were independent risk factors for subsidence. Presence of prongs on cages and posterior fusion 2 or more levels above and below corpectomy level had lower rates and odds of subsidence. Infection and cage placement in the thoracic or lumbar region had greater extent of subsidence when subsidence was present. CONCLUSION:: Expandable cages had higher rates and risk of subsidence compared to static cages. When subsidence was present, expandable cages had greater magnitudes of subsidence. Other factors including footplate-to-vertebral body endplate ratio, prongs, extent of supplemental posterior fusion, spinal region, and diagnosis also impacted subsidence.

Concepts: Cohort study, Cohort, Retrospective, Rates, Assessment, Cage, Lumbar, Multivariate

28

Carlo Giacomini (1840-1898) was a prominent Italian anatomist, neuroscientist, and professor at the University of Turin. Early in his career, he conducted clinical investigations with the physiologist Angelo Mosso (1846-1910) that culminated in the first recording of brain pulsations in a human subject. Anatomic features named after him include the limbus Giacomini, Giacomini’s vertebrae, and the vein of Giacomini. Pushing anatomy research to reconsider anthropological studies of the late 19 century, Giacomini strongly refuted the theory connecting criminality to atavistic morphological characteristics. A tireless scientist, he was the first to describe the os odontoideum in 1886 and to suggest that the presence of an incompetent odontoid process may alter the motion of craniovertebral junction, anticipating the concept of spinal instability. In this essay we highlight the life and scientific contributions of Carlo Giacomini, with emphasis on his contributions to neuroscience.

Concepts: Psychology, Medicine, Biology, Physiology, Greek loanwords, Anatomy, Human anatomy, History of anatomy

28

: In transarterial embolization of anterior cranial fossa and tentorial dural arteriovenous fistula (DAVF), acute angulation of the feeding artery off the internal carotid artery (ICA) may render stable distal catheterization and, therefore, successful transarterial treatment difficult. In some anatomic dispositions, following selection of the feeding artery, subsequent forward force may lead to prolapse of the microcatheter into the ICA rather than advancing it into either the ophthalmic artery or the meningohypophyseal trunk.

Concepts: Internal carotid artery, Common carotid artery, External carotid artery, Internal jugular vein, Arteriovenous fistula, Fistula, Arteries of the head and neck, Ophthalmic artery

28

BACKGROUND:: Anatomic diversity among cerebellar arteriovenous malformations (AVMs) calls for a classification that is intuitive and surgically informative. Selection tools like the Spetzler-Martin grading system are designed to work best with cerebral AVMs but have shortcomings with cerebellar AVMs. OBJECTIVE:: To define subtypes of cerebellar AVMs that clarify anatomy and surgical management, to determine results according to subtypes, and to compare predictive accuracies of the Spetzler-Martin and supplementary systems. METHODS:: From a consecutive surgical series of 500 patients, 60 had cerebellar AVMs, 39 had brainstem AVMs and were excluded, and 401 had cerebral AVMs. RESULTS:: Cerebellar AVM subtypes were as follows: 18 vermian, 13 suboccipital, 12 tentorial, 12 petrosal, and 5 tonsillar. Patients with tonsillar and tentorial AVMs fared best. Cerebellar AVMs presented with hemorrhage more than cerebral AVMs (P < .001). Cerebellar AVMs were more likely to drain deep (P = .04) and less likely to be eloquent (P < .001). The predictive accuracy of the supplementary grade was better than that of the Spetzler-Martin grade with cerebellar AVMs (areas under the receiver-operating characteristic curve, 0.74 and 0.59, respectively). The predictive accuracy of the supplementary system was consistent for cerebral and cerebellar AVMs, whereas that of the Spetzler-Martin system was greater with cerebral AVMs. CONCLUSION:: Patients with cerebellar AVMs present with hemorrhage more often than patients with cerebral AVMs, justifying an aggressive treatment posture. The supplementary system is better than the Spetzler-Martin system at predicting outcomes after cerebellar AVM resection. Key components of the Spetzler-Martin system such as venous drainage and eloquence are distorted by cerebellar anatomy in ways that components of the supplementary system are not. ABBREVIATIONS:: AICA, anterior inferior cerebellar artery;AVM, arteriovenous malformationmRS, modified Rankin ScalePICA, posterior inferior cerebellar arteryROC, receiver-operating characteristicSCA, superior cerebellar artery.

Concepts: Cerebral cortex, Cerebellum, Anterior inferior cerebellar artery, Arteries of the head and neck, Arteriovenous malformation, Basilar artery, Superior cerebellar artery, Inferior cerebellar veins

28

BACKGROUND:: The Pipeline embolization device (PED) is the latest technology available for intracranial aneurysm treatment. OBJECTIVE:: To report early postmarket results with the PED. METHODS:: This study was a prospective registry of patients treated with PEDs at 7 American neurosurgical centers subsequent to Food and Drug Administration approval of this device. Data collected included clinical presentation, aneurysm characteristics, treatment details, and periprocedural events. Follow-up data included degree of aneurysm occlusion and delayed (> 30 days after the procedure) complications. RESULTS:: Sixty-two PED procedures were performed to treat 58 aneurysms in 56 patients. Thirty-seven of the aneurysms (64%) treated were located from the cavernous to the superior hypophyseal artery segment of the internal carotid artery; 22% were distal to that segment, and 14% were in the vertebrobasilar system. A total of 123 PEDs were deployed with an average of 2 implanted per aneurysm treated. Six devices were incompletely deployed; in these cases, rescue balloon angioplasty was required. Six periprocedural (during the procedure/within 30 days after the procedure) thromboembolic events occurred, of which 5 were in patients with vertebrobasilar aneurysms. There were 4 fatal postprocedural hemorrhages (from 2 giant basilar trunk and 2 large ophthalmic artery aneurysms). The major complication rate (permanent disability/death resulting from perioperative/delayed complication) was 8.5%. Among 19 patients with 3-month follow-up angiography, 68% (13 patients) had complete aneurysm occlusion. Two patients presented with delayed flow-limiting in-stent stenosis that was successfully treated with angioplasty. CONCLUSION:: Unlike conventional coil embolization, aneurysm occlusion with PED is not immediate. Early complications include both thromboembolic and hemorrhagic events and appear to be significantly more frequent in association with treatment of vertebrobasilar aneurysms. ABBREVIATIONS:: ICA, internal carotid arteryPED, Pipeline embolization devicePITA, Pipeline for the Intracranial Treatment of AneurysmsPUFS, Pipeline for Uncoilable or Failed AneurysmsTEE, thromboembolic event.

Concepts: Atherosclerosis, Internal carotid artery, Common carotid artery, Radiology, Aneurysm, Arteries of the head and neck, Circle of Willis, Ophthalmic artery