Please check out the accompanying podcast of this blog post (also known as “Annotated Bibliography”):
1. Deng X, Zhang Y, Xu L, et al. Comparison of language cortex reorganization patterns between cerebral arteriovenous malformations and gliomas: a functional MRI study. J Neurosurg. 2015;122(May):996–1003. doi:10.3171/2014.12.JNS14629.
The authors retrospectively reviewed the clinical and imaging data of 63 patients with left sided unruptured cerebral AVM’s and 38 patients with a left sided glioma who underwent fMRI. The patients were further categorized by lesion location into either the Broca area subgroup or the Wernicke area subgroup. Lateralization BOLD signal indices were calculated separately for Broca and Wernicke areas. Of the 34 patients in the AVM-BA subgroup, right-sided lateralization of Broca area was detected in 9 patients (26.5%), and right-sided lateralization of the Wernicke area was detected in 4 (11.8%). Of the 29 patients in the AVM-WA subgroup, 2 (6.9%) had right-sided lateralization of the Broca area, and 13 (44.8%) had right-sided lateralization of the Wernicke area. In the glioma group, 15.8% showed right-sided lateralization of the Wernicke area, and no patient showed right-sided lateralization of Broca area. They conclude that the potential for reorganization is much greater in the AVM group, and that isolated reorganization of solely Broca or solely Wernicke areas will occur when AVM nidus is located specifically near those areas.
The single task performed in this study by all patients was a silent reading task. The authors note that activations of both the Broca and the Wernicke areas were observed in all the patients, but multiple tasks may improve the accurate and reliability of the conclusion.
2. Ganko R, Rao PJ, Phan K, Mobbs RJ. Can Bacterial Infection by Low Virulent Organisms Be a Plausible Cause for Symptomatic Disc Degeneration? A Systematic Review. Spine. 2015;40(10):E587–E592. doi:10.1097/BRS.0000000000000832.
The authors performed a search of 6 electronic databases for studies investigating the potential relationship between disc infection as a cause for degenerative disc disease and symptomatic neck/back pain or radiculopathy. Nine relevant studies involving 602 patients with degenerative disc disease or pain were identified. Overall pooled infection prevalence in all studies was 36.2%. The majority of infections were due to Propionibacterium acnes. While the direct link between infection and back pain can not be excluded, they conclude that there is still a lack of robust clinical evidence to conclusively demonstrate the link between disc infection as a causal mechanism of disc degeneration and radiculopathy. The authors note several limitations of the studies included in the systematic review including that the studies are predominantly observational and nonrandomized in design and thus are subject to selection bias, and that the methodology of infection detection varied between the studies.
So in other words, it remains interesting to think about, but we still don’t know one way or the other if the low grade infection underlying disc degeneration/back pain hypothesis has merit.
3. Goldschlager T, Dea N, Boyd M, et al. Giant cell tumors of the spine: has denosumab changed the treatment paradigm? J Neurosurg Spine. 2015;22(May):1–8. doi:10.3171/2014.10.SPINE13937.
Giant cell tumors histologically show nodules of osteoclast-like giant cells, from which the tumors arise. Osteoclasts express the “Receptor Activator of Nuclear factor Kappa B Ligand” (RANKL), which is an essential mediator for osteoclast survival. Denosumab is a monoclonal antibody against RANKL, and showed tumor response in 86% of patients in a Phase 2 study (Thomas et al., Lancet Oncol 11:275–280, 2010). This study was a prospective, consecutive series of 5 patients with primary spinal GCTs that were treated with denosumab from 4 centers. The response to denosumab varied from 10% reduction of tumor size in 3 patients, 40% reduction in 1 patients, and >90% reduction in the fifth patient (who did not receive surgery). Final histological investigation revealed complete obliteration of all tumor cells and replacement with sclerotic fibro-osseous tissue with interstitial hemosiderin. Mean follow up was 12 months. The authors note that following denosumab treatment there was remodeling of the vertebrae, but the extracompartmental GCT tended to shrink only slightly to calcify. Also, the epidural GCT had greater regression following denosumab treatment. They conclude that denosumab has the potential to change the treatment paradigm for spinal GCT.
Five figures including three PET/CT figures. Tough to get large patient numbers with this tumor, but the results are very impressive.
4. Murphy DT, Kavanagh EC, Poynton A, Chan VO, Moynagh MR, Eustace S. MR epidurography: distribution of injectate at caudal epidural injection. Skeletal Radiol. 2015;44:565–571. doi:10.1007/s00256-014-1963-x.
This is an interesting study evaluating the distribution of gadolinium contrast within the epidural space following epidural injection via the sacral hiatus. Twenty patients who were referred with symptomatic low back pain were treated with either 10 ml (9/20) or 20 ml (11/20) of injectate administered. Gadolinium was included in the injection. The patients proceeded to MRI where sagittal and coronal T1-weighted fat-saturated sequences were acquired. Specifics regarding the injectate are: 80–160 mg of methylprednisolone acetate and 4–8 ml 0.25 % bupivacaine, made up to a total volume of either 10 or 20 ml with sterile saline. Magnevist was included in all cases at a standard 1:200 concentration (0.1 ml in 20 ml of solution). Gadolinium was observed at or above the L3/4 disc level in all 11 patients who received 20 ml (100 %), compared with only five of nine patients who received 10 ml (56 %). In 5 patients, the higher volume showed contrast up to the T12/L1 level. Despite showing that a larger volume of injectate gets medication to a higher level in the spine as would be expected, it is unknown whether patients fare better clinically with this higher volume.
Impressive images, which in one case show epidural contrast near the cervicothoracic junction from the sacral hiatus injection. 4 MR figures.
5. Scott WW, Sharp S, Figueroa S a, Madden CJ, Rickert KL. Clinical and radiological outcomes following traumatic Grade 1 and 2 carotid artery injuries: a 10-year retrospective analysis from a Level 1 trauma center. J Neurosurg. 2015;122:1196–1201. doi:10.3171/2014.4.JNS132235.
The authors describe a retrospective review of 117 Grade 1-2 BCIs in 100 patients. Final imaging at 60 days showed that 64% of cases had resolved, 13% of cases were radiographically stable, and 9% were improved, whereas 14% radiographically worsened. 54% of cases were treated with aspirin, 31% received no treatment, and the remained received various treatments. One infarct related to the Grade 2 BCI was identified. Despite a 14% rate of radiographic worsening in the Grade 1 and 2 BCIs cohort, there were no adverse clinical outcomes associated with these radiographic changes. They conclude that use of ASA or other antiplatelet or anticoagulant medications in these low-grade BCIs did not appear to correlate with radiographic injury, and there use may not eliminate the small risk of cerebral infarction.
6. Scott WW, Sharp S, Figueroa S a, Madden CJ, Rickert KL. Clinical and radiological outcomes following traumatic Grade 3 and 4 vertebral artery injuries: a 10-year retrospective analysis from a Level 1 trauma center. J Neurosurg. 2015;122:1202–1207. doi:10.3171/2014.4.JNS132235.
This is a retrospective review of 79 Grade 3-4 blunt vertebral cerebrovascular injuries in (Grade 3 injuries are defined as stenosis of the vessel greater than 50% or the development of a pseudoaneurysm, and Grade 4 injuries were defined as complete vessel occlusion). Repeat imaging of Grade 3 blunt VA injuries showed that 39% of injuries were radiographically stable, 43% resolved, and 13% improved, while 1 injury radiographically worsened. All Grade 3 injuries that were treated were managed with aspirin or clopidogrel alone, as were the majority of Grade 4 injuries. There were 3 cerebral infarctions thought to be related to Grade 4 blunt VA injuries, which were likely present on admission, and all 3 of these patients died. No cerebral infarctions directly related to Grade 3 blunt VA injuries were identified. They conclude that the majority of high-grade blunt VA injuries remain stable or are improved at final follow-up.
7. Peterson EC, Heros R. Editorial: Mild narrowing of the cervical carotid is noted. J Neurosurg. 2015;122(5):1193–1195. doi:10.3171/2014.7.JNS141247.
Take away points: The Biffl classification (Biffl WL, Moore EE, Offner PJ, Brega KE, Franciose RJ,Burch JM: Blunt carotid arterial injuries: implications of a new grading scale. J Trauma 47:845–853, 1999) divides up the injuries into 4 categories – <25% narrowing, 25-50% narrowing, pseudoaneurysm, and occlusion. Previous studies have shown high rates of stroke for carotid occlusions (64%), but low rates for vertebral occlusions (9%).
Most other large studies on lower-grade lesions show stroke rates higher than the Parkland series (1%), on the order of 6-10% for grade 1-2 injuries.
Many strokes occur prior to the time when treatment is possible, up to 90% in some series. Given the difficulties of instituting anticoagulant therapy in polytrauma patients, it bears questioning how effective any treatment would be.
Given its safety profile and similar efficacy to anticoagulation with heparin, aspirin has emerged as the preferred treatment choice for low-grade BCVI.
These lesions are dynamic, and have a significant risk of worsening over time. Biffl found that 45% of Grade 2 lesions progressed to pseudoaneurysms (Biffl WL, Ray CE Jr, Moore EE, Franciose RJ, Aly S, Heyrosa MG, et al: Treatment-related outcomes from blunt cerebrovascular injuries: importance of routine follow-up arteriography. Ann Surg 235:697–707, 2002).
8. Steinberger J, Skovrlj B, Caridi JM, Cho SK. The Top 100 Classic Papers in Lumbar Spine Surgery. Spine. 2015;40(10):740–747. doi:10.1097/BRS.0000000000000847.
Interesting listing of the most frequently cited papers. The most cited article was found to be the paper from 1990 by Boden et al that described MRI findings in individuals without back pain, sciatica, and neurogenic claudication showing that spinal stenosis and herniated discs can be incidentally found when scanning patients (Boden SD , Davis DO , Dina TS , et al. Abnormal magnetic-resonance scans of the lumbar spine in asymptomatic subjects. A prospective investigation . J Bone Joint Surg Am 1990; 72:403–8).
Similarly, the second most cited study similarly showed that asymptomatic patients who underwent lumbar spine MRI frequently had lumbar pathology (Jensen MC , Brant-Zawadzki MN , et al. Magnetic resonance imaging of the lumbar spine in people without back pain. N Engl J Med 1994 ; 331:69–73). 98 asymptomatic patients underwent lumbar spine MRI, with 52% having a bulge at 1 level, 26% having a protrusion, and 1% having a disc extrusion.
The third most cited paper was the 2000 publication of Fairbank and Pynsent reviewing the Oswestry Disability Index (Fairbank JC , Pynsent PB . The Oswestry Disability Index . Spine 2000; 25:2940–52).
