1. Maigne JY, Doursounian L, Jacquot F. Classification of fractures of the coccyx from a series of 104 patients. Eur Spine J 2020;29:2534–42. Available from: https://doi.org/10.1007/s00586-019-06188-7

The authors saw 1142 new consecutive patients presenting with acute or chronic coccydynia at their clinic. Among them, 104 were diagnosed with a fracture of the coccyx. The definitive diagnosis of fracture was made with the use of a standard X-ray film or a CT scan. In cases with nonunion, dynamic films were essential for studying the mobility of the broken segment.

They identified three major possible mechanisms in coccyx fractures: flexion, compression and extension, each associated with certain fracture patterns. Accordingly, the patients were divided into three groups, according to the mechanism of the fracture.

Flexion fractures (type 1) comprised patients with a history of external trauma—a fall or a direct blow on the sacrococcygeal junction. The fracture involved S5 or the first coccygeal vertebra (Co1), when and only when this vertebra was fused to S5, thus functionally belonging to the sacrum. The mechanism was likely a forced flexion of the lower sacrum or upper coccyx.

Compression fractures (type 2) also comprised patients with a history of external trauma, but the likely mechanism was a compression of the first independent coccygeal vertebra, namely Co2 or Co1 when it was not fused to S5. The fracture line was vertical, extending from the upper to the lower end plate. Thus, they were intra articular fractures.

Extension fractures (type 3) consisted in obstetrical fractures. The lower coccyx was involved. The likely mechanism was a forced extension of the coccyx occurring during the delivery.

12 figures, 1 table

2. Ospel JM, Menon BK, Demchuk AM, et al. Clinical course of acute ischemic stroke due to medium vessel occlusion with and without intravenous alteplase treatment. Stroke 2020;51:3232–40. Available from: https://www.ahajournals.org/doi/10.1161/STROKEAHA.120.030227

Available data on the clinical course of patients with acute ischemic stroke due to medium vessel occlusion (MeVO) are mostly limited to those with M2 segment occlusions. Outcomes are generally better compared with more proximal occlusions, but many patients will still suffer from severe morbidity. The authors aimed to determine the clinical course of acute ischemic stroke due to MeVO with and without intravenous alteplase treatment.

Patients with MeVO (M2/M3/A2/A3/P2/P3 occlusion) from a couple of trials with rather tortured eponyms, the INTERRSeCT (The Identifying New Approaches to Optimize Thrombus Characterization for Predicting Early Recanalization and Reperfusion With IV Alteplase and Other Treatments Using Serial CT Angiography) and PRoveIT (Precise and Rapid Assessment of Collaterals Using Multi-Phase CTA in the Triage of Patients With Acute Ischemic Stroke for IA Therapy) studies were included. Baseline characteristics and clinical outcomes were summarized using descriptive statistics. The primary outcome was a modified Rankin Scale score of 0 to 1 at 90 days, describing excellent functional outcome.

They compared outcomes between patients with versus without intravenous alteplase treatment and between patients who did and did not show recanalization on follow-up computed tomography angiography.

Among 258 patients with MeVO, the median baseline NIH Stroke Scale score was 7. A total of 72.1% (186/258) patients were treated with intravenous alteplase and in 41.8% (84/201), recanalization of the occlusion (revised arterial occlusive lesion score 2b/3) was seen on follow-up CTA. Excellent functional outcome was achieved by 50.0% (129/258), and 67.4% (174/258) patients gained functional independence, while 8.9% (23/258) patients died within 90 days. Recanalization was observed in 21.4% (9/42) patients who were not treated with alteplase and 47.2% (75/159) patients treated with alteplase. Early recanalization was significantly associated with excellent functional outcome, while intravenous alteplase was not.

They conclude that the clinical course of acute ischemic stroke due to MeVO with medical management is poor: 50% of patients in this study did not achieve excellent outcome at 90 days with best medical management and 33% were not functionally independent. Recanalization on follow-up imaging was strongly associated with favorable outcomes but was only achieved in 47% in spite of treatment with intravenous alteplase.

Performing EVT in MeVO is challenging, as the relatively smaller vessel size and more distal location compared with large vessel occlusions potentially carry an increased risk of procedural complications. However, given the preliminary evidence for efficacy of EVT and the high number of unfavorable outcomes we observed in this study, the authors consider that EVT should be explored as an alternative treatment option.

3 figures, 3 tables

3. Esterman M, Stumps A, Jagger-Rickels A, et al. Evaluating the evidence for a neuroimaging subtype of posttraumatic stress disorder. Sci Transl Med 2020;9343(November):1–13

Posttraumatic stress disorder (PTSD) is a heterogeneous condition in its symptom presentation, long-term outcome, response to treatment, and neurobiology. Although there have been important discoveries in our understanding of the neurobiological systems associated with PTSD, this heterogeneity has impeded the identification of consistent biomarkers, which are rarely strong enough to make inferences at the individual level. One approach to biomarker identification has been the use of functional neuroimaging, often alongside neuropsychological measurements, to identify subtypes of patients with dysfunction in neural networks that may underlie cognitive impairments and clinical symptoms.

In a recent study, Etkin et al. (Sci. Transl. Med. 11, eaal3236 (2019)) identified a PTSD subtype with a specific neurocognitive marker, namely, impaired verbal memory alongside ventral attention network (VAN) dysfunction and these same individuals responded poorly to psychotherapy. These authors sought to replicate and extend the work of Etkin et al.

The authors attempted to conceptually replicate and extend these findings in a similar cohort of combat-exposed veterans (n = 229) tested using a standardized battery of neuropsychological tests and a priori criteria for cognitive impairments. First, they conducted identical and complementary analyses to determine whether subjects with PTSD and neuropsychologically defined verbal memory deficits exhibited the VAN connectivity biomarker. Second, they examined whether cognitive deficits in other domains implicated in PTSD (executive functioning and attention) exhibited the VAN signature. Across multiple measures of verbal memory, they did not find that the subgroup of individuals with PTSD and memory impairments had lower VAN connectivity. However, a subgroup of individuals with PTSD and attentional impairments did have lower VAN connectivity, suggesting that the original subtype could have been related to attention and not memory impairments. Overall, their findings suggest that the previously identified memory-impaired PTSD subtype may not generalize.

2 figures, 3 tables, no imaging

4. Klebel T, Reichmann S, Polka J, et al. Peer review and preprint policies are unclear at most major journals. PLoS One 2020;15:e0239518. Available from: https://dx.plos.org/10.1371/journal.pone.0239518

Scholarly publishing, as the steward of the scientific record, has a great deal of power to steer researcher practices. Despite emergent trends towards greater openness and transparency in all areas of research publication practices of academic journals can remain something of a black box for authors and readers. Processes of editorial handling and peer review are usually hidden behind curtains of confidentiality or anonymity. But worse, journal policies which should orient authors and readers as to the editorial standards employed by individual journals, including what the general type of peer review system is or whether preprinting manuscripts is allowed, have been suggested to be often unclear.

The authors investigated the clarity of policies of 171 major academic journals across disciplines regarding peer review and preprinting. 31.6% of journals surveyed do not provide information on the type of peer review they use. Information on whether preprints can be posted or not is unclear in 39.2% of journals. 58.5% of journals offer no clear information on whether reviewer identities are revealed to authors. Around 75% of journals have no clear policy on co-reviewing, citation of preprints, and publication of reviewer identities. Information regarding practices of open peer review is even more scarce, with <20% of journals providing clear information.

Mathematics (STEM) and Medicine, which are in most cases clearer than the average journal, and journals from the Social Sciences and Humanities (SSH), which are less clear than the average journal. Journals from the life sciences and earth sciences are well above average regarding clarity of policies, with journals from physics & mathematics, chemical & materials sciences and health & medical sciences being slightly above average. Journals from engineering & computer science are slightly below average, followed by journals from the social sciences, and humanities, literature & arts.

7 figures, 1 table

5. Kühn AL, Vardar Z, Kraitem A, et al. Biomechanics and hemodynamics of stent-retrievers. J Cereb Blood Flow Metab 2020;40:2350–65. Available from: http://journals.sagepub.com/doi/10.1177/0271678X20916002

This review summarizes the history of intraarterial treatment of stroke, introduces the biomechanics of embolus extraction with stent-retrievers, describes technical aspects of the intervention, provides a description of hemodynamic implications of stent-retriever embolectomy, and proposes future directions for a more comprehensive, multi-modal endovascular approach for the treatment of acute ischemic stroke.

Current thrombectomy techniques can be divided into three main groups: (1) use of a large bore aspiration catheter, (2) use of a stent-retriever or (3) a combined approach using an aspiration catheter together with a stent-retriever.

The enabling technology for aspiration thrombectomy today is the manufacturing of large bore aspiration catheters that enable safe navigation to the middle cerebral artery. A direct aspiration first pass technique (ADAPT) uses a large bore aspiration catheter which is positioned at the face of the thrombus. Aspiration is then applied until the system becomes occlusive, indicating that the proximal portion of the clot has been successfully sucked into the catheter tip. The aspiration catheter is subsequently removed while aspiration is maintained. Recent randomized trials of the aspiration approach as compared to gold-standard stent-retriever thrombectomy show comparable results in terms of successful recanalization and good clinical outcomes. The key advantage of the ADAPT technique is relative simplicity of the procedure and less cost.

Mechanical thrombectomy with a stent-retriever is used to engage the clot by deploying the stent-retriever at the location of the thrombus in the occluded artery. The device is then allowed to intercalate with the clot, attempting to engage the thrombus in the stent struts, before the system is removed. There are numerous variations of technique when deploying a stent-retriever, including the combined use of a large bore aspiration catheter proximally and a stent retriever deployed distally (Solumbra technique, Aspiration-Retriever Technique for Stroke (ARTS), SAVE technique).

Mechanical thrombectomy has revolutionized acute ischemic stroke treatment. The first-generation stent retrievers are easy to use and achieve high rates of reperfusion. Nevertheless, there is still a subgroup of patients in whom the clot cannot be completely removed. About 20% of emboli are resistant to modern retrieval approaches, either requiring multiple attempts of thrombectomy or completely intractable to recanalization.

7 figures, 1 table

6. Qiu T, Chanchotisatien A, Qin Z, et al. Imaging characteristics of adult H3 K27M-mutant gliomas. J Neurosurg 2020;133:1662–70. Available from: https://thejns.org/view/journals/j-neurosurg/133/6/article-p1662.xml

The study included 66 cases (40 in men, 26 in women) of H3 K27M-mutant glioma in adult patients. Tumors were found in the following sites: thalamus (n = 38), brainstem (n = 6), brainstem with cerebellar or thalamic involvement (n = 4), whole brain (n = 8), corpus callosum (n = 3), hypothalamus (n = 1), hemispheres (n = 2), and spinal cord (n = 4). All pure brainstem lesions were located posteriorly, and all corpus callosal lesions were in the genu. Most spinal tumors were long-segment lesions. Hemispheric lesions mimicked gliomatosis cerebri in presentation, with the addition of traditional midline structure involvement. Most tumors were solid with relatively uniform signals on unenhanced MRI. Of the 61 cases with contrast-enhanced MR images, 36 (59%) showed partial to no enhancement, whereas 25 (41%) showed diffuse or irregular peripheral enhancement. Hemorrhage and edema were rare.

8 figures with many MR images

7. Macha K, Hoelter P, Siedler G, et al. Multimodal CT or MRI for IV thrombolysis in ischemic stroke with unknown time of onset. Neurology 2020;95:e2954–64. Available from: http://www.neurology.org/lookup/doi/10.1212/WNL.0000000000011059

The clinical management of ischemic stroke in the unknown or extended time window is challenging. Treatment with recombinant tissue plasminogen activator (rtPA) is approved for the first 4.5 hours after symptom onset. However, the Extending the Time for Thrombolysis in Emergency Neurologic Deficits (EXTEND) trial suggested the benefit of IV thrombolysis in the up to 9-hour time window, presuming that CT or magnetic resonance (MR) perfusion imaging identified salvageable brain tissue at risk. In addition, the Efficacy and Safety of MRI-Based Thrombolysis in Wake-Up Stroke (WAKE-UP) trial demonstrated the efficacy and safety of IV thrombolysis in patients with acute ischemic stroke and unknown time of symptom onset who showed DWI–FLAIR mismatch on MRI. Smaller trials investigated the safety of IV thrombolysis in patients with wake-up stroke on the basis of noncontrast CT.  Imaging-based selection was furthermore used successfully in trials on endovascular treatment up to 24 hours after the time when the patient was last seen normal. Currently, the ideal imaging protocol for the selection of patients with stroke in the extended time window remains to be determined.

The objective of this study was to investigate differences in procedure times, safety, and efficacy outcomes comparing 2 different protocols for thrombolysis in the extended or unknown time window after stroke onset using either multimodal CT imaging or MRI at a university stroke center.

IV thrombolysis was performed in 100 patients (54.3%) based on multimodal CT imaging and in 84 patients (45.7%) based on MRI. Baseline clinical data, including stroke severity and time from last seen normal to hospital admission, were similar in patients with CT and MRI. Door to- needle times were shorter in patients with CT-based selection (median 45 minutes vs 75 minutes. No differences were detected regarding the incidence of symptomatic intracranial hemorrhage (2 [2.0%] vs 4 [4.8%] and favorable outcome at day 90 (25 [33.8%] vs 33 [42.9%].

IV thrombolysis in ischemic stroke in the unknown or extended time window appeared safe in CT- and MRI-selected patients, while the use of CT imaging led to faster door-to-needle times.

3 figures, 4 tables, no imaging

8. Xie T, Pan L, Yang M, et al. Analysis of spinal angiograms that missed diagnosis of spinal vascular diseases with venous hypertensive myelopathy: the non-technical factors. Eur Spine J 2020;29:2441–48. Available from: https://doi.org/10.1007/s00586-020-06422-7

“Standard spinal angiography” did not find the lesion in 14 patients. Additional angiography was performed and detected the lesions. Eight patients were found lesions supplied by carotid arteries or iliac arteries, including 2 cranial DAVF with internal carotid artery blood supply, 3 cranial DAVF with external carotid artery blood supply and 2 pelvic AVF with internal iliac artery blood supply and 1 pelvic AVM with internal iliac artery blood supply. So the first angio did not do a complete vascular search.  This important aspect of spinal angiography for these lesions is well known.

I have a much harder time with the second group: Six patients were caused by stenosis of spinal draining vein, including 3 stenosis of the third lumbar veins and 3 stenosis of left renal veins combined with the reno–spinal trunk. Details about this group is scant. I am skeptical that this is a real diagnosis.

The American Society of Neuroradiology is accredited by the Accreditation Council for Continuing Medical Education (ACCME) to provide continuing medical education for physicians. Visit the ASNR Education Connection website to claim CME credit for this podcast.

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