Abstracts of the 2017 AANS/CNS Joint Section on Disorders of the Spine and Peripheral Nerves Las Vegas, Nevada • March 8–11, 2017
Oral Presentations 2016 AANS Annual Scientific Meeting Chicago, IL • April 30–May 4, 2016
Published online April 1, 2016; DOI: 10.3171/2016.4.JNS.AANS2016abstracts
Is there a regional difference in morphology interpretation of A3 and A4 fractures among different cultures?
Gregory D. Schroeder, Christopher K. Kepler, John D. Koerner, Jens R. Chapman, Carlo Bellabarba, F. Cumhur Oner, Max Reinhold, Marcel F. Dvorak, Bizhan Aarabi, Luiz Vialle, Michael G. Fehlings, Shanmuganathan Rajasekaran, Frank Kandziora, Klaus J. Schnake, and Alexander R. Vaccaro
The aim of this study was to determine if the ability of a surgeon to correctly classify A3 (burst fractures with a single endplate involved) and A4 (burst fractures with both endplates involved) fractures is affected by either the region or the experience of the surgeon.
A survey was sent to 100 AOSpine members from all 6 AO regions of the world (North America, South America, Europe, Africa, Asia, and the Middle East) who had no prior knowledge of the new AOSpine Thoracolumbar Spine Injury Classification System. Respondents were asked to classify 25 cases, including 6 thoracolumbar burst fractures (A3 or A4). This study focuses on the effect of region and experience on surgeons’ ability to properly classify these 2 controversial fracture variants.
All 100 surveyed surgeons completed the survey, and no significant regional (p > 0.50) or experiential (p > 0.21) variability in the ability to correctly classify burst fractures was identified; however, surgeons from all regions and with all levels of experience were more likely to correctly classify A3 fractures than A4 fractures (p < 0.01). Further analysis demonstrated that no region predisposed surgeons to increasing their assessment of severity of burst fractures.
A3 and A4 fractures are the most difficult 2 fractures to correctly classify, but this is not affected by the region or experience of the surgeon; therefore, regional variations in the treatment of thoracolumbar burst fractures (A3 and A4) is not due to differing radiographic interpretation of the fractures.
Treatment of isolated cervical facet fractures: a systematic review
Christopher K. Kepler, Alexander R. Vaccaro, Eric Chen, Alpesh A. Patel, Henry Ahn, Ahmad Nassr, Christopher I. Shaffrey, James Harrop, Gregory D. Schroeder, Amit Agarwala, Marcel F. Dvorak, Daryl R. Fourney, Kirkham B. Wood, Vincent C. Traynelis, S. Tim Yoon, Michael G. Fehlings, and Bizhan Aarabi
In this clinically based systematic review of cervical facet fractures, the authors’ aim was to determine the optimal clinical care for patients with isolated fractures of the cervical facets through a systematic review.
A systematic review of nonoperative and operative treatment methods of cervical facet fractures was performed. Reduction and stabilization treatments were compared, and analysis of postoperative outcomes was performed. MEDLINE and Scopus databases were used. This work was supported through support received from the Association for Collaborative Spine Research and AOSpine North America.
Eleven studies with 368 patients met the inclusion criteria. Forty-six patients had bilateral isolated cervical facet fractures and 322 had unilateral isolated cervical facet fractures. Closed reduction was successful in 56.4% (39 patients) and 63.8% (94 patients) of patients using a halo vest and Gardner-Wells tongs, respectively. Comparatively, open reduction was successful in 94.9% of patients (successful reduction of open to closed reduction OR 12.8 [95% CI 6.1–26.9], p < 0.0001); 183 patients underwent internal fixation, with an 87.2% success rate in maintaining anatomical alignment. When comparing the success of patients who underwent anterior versus posterior procedures, anterior approaches showed a 90.5% rate of maintenance of reduction, compared with a 75.6% rate for the posterior approach (anterior vs posterior OR 3.1 [95% CI 1.0–9.4], p = 0.05).
In comparison with nonoperative treatments, operative treatments provided a more successful outcome in terms of failure of treatment to maintain reduction for patients with cervical facet fractures. Operative treatment appears to provide superior results to the nonoperative treatments assessed.
Predictors of intramedullary lesion expansion rate on MR images of patients with subaxial spinal cord injury
Elizabeth Le, Bizhan Aarabi, David S. Hersh, Kathirkamanthan Shanmuganathan, Cara Diaz, Jennifer Massetti, and Noori Akhtar-Danesh
Studies of preclinical spinal cord injury (SCI) in rodents indicate that expansion of intramedullary lesions (IMLs) seen on MR images may be amenable to neuroprotection. In patients with subaxial SCI and motor-complete American Spinal Injury Association (ASIA) Impairment Scale (AIS) Grade A or B, IML expansion has been shown to be approximately 900 μm/hour. In this study, the authors investigated IML expansion in a cohort of patients with subaxial SCI and AIS Grade A, B, C, or D.
Seventy-eight patients who had at least 2 MRI scans within 6 days of SCI were enrolled. Data were analyzed by regression analysis.
In this cohort, the mean age was 45.3 years (SD 18.3 years), 73 patients were injured in a motor vehicle crash, from a fall, or in sport activities, and 77% of them were men. The mean Injury Severity Score (ISS) was 26.7 (SD 16.7), and the AIS grade was A in 23 patients, B in 7, C in 7, and D in 41. The mechanism of injury was distraction in 26 patients, compression in 22, disc/osteophyte complex in 29, and Chance fracture in 1. The mean time between injury onset and the first MRI scan (Interval 1) was 10 hours (SD 8.7 hours), and the mean time to the second MRI scan (Interval 2) was 60 hours (SD 29.6 hours). The mean IML lengths of the first and second MR images were 38.8 mm (SD 20.4 mm) and 51 mm (SD 36.5 mm), respectively. The mean time from the first to the second MRI scan (Interval 3) was 49.9 hours (SD 28.4 hours), and the difference in IML lengths was 12.6 mm (SD 20.7 mm), reflecting an expansion rate of 366 μm/ hour (SD 710 μm/hour). IML expansion in patients with AIS Grades A and B was 918 μm/hour (SD 828 μm/hour), and for those with AIS Grades C and D, it was 21 μm/hour (SD 304 μm/hour). Univariate analysis indicated that AIS Grade A or B versus Grades C or D (p < 0.0001), traction (p= 0.0005), injury morphology (p < 0.005), the surgical approach (p= 0.009), vertebral artery injury (p= 0.02), age (p < 0.05), ISS (p < 0.05), ASIA motor score (p < 0.05), and time to decompression (p < 0.05) were all predictors of lesion expansion. In multiple regression analysis, however, the sole determinant of IML expansion was AIS grade (p < 0.005).
After traumatic subaxial cervical spine or spinal cord injury, patients with motor-complete injury (AIS Grade A or B) had a significantly higher rate of IML expansion than those with motor-incomplete injury (AIS Grade C or D).
Arterial injuries after penetrating brain injury in civilians: risk factors on admission head computed tomography
Uttam K. Bodanapally, Nitima Saksobhavivat, Kathirkamanathan Shanmuganathan, Bizhan Aarabi, and Ashis K. Roy
The object of this study was to determine the specific CT findings of the injury profile in penetrating brain injury (PBI) that are risk factors related to intracranial arterial injuries.
The authors retrospectively evaluated admission head CTs and accompanying digital subtraction angiography (DSA) studies from patients with penetrating trauma to the head in the period between January 2005 and December 2012. Two authors reviewed the CT images to determine the presence or absence of 30 injury profile variables and quantified selected variables. The CT characteristics in patients with and without arterial injuries were compared using univariate analysis, multivariate analysis, and receiver operating characteristic (ROC) curve analysis to determine the respective risk factors, independent predictors, and optimal threshold values for the continuous variables.
Fifty-five patients were eligible for study inclusion. The risk factors for an intracranial arterial injury on univariate analysis were an entry wound over the frontobasal-temporal regions, a bihemispheric wound trajectory, a wound trajectory in proximity to the circle of Willis (COW), a subarachnoid hemorrhage (SAH), a higher SAH score, an intraventricular hemorrhage (IVH), and a higher IVH score. A trajectory in proximity to the COW was the best predictor of injury (OR 6.8 and p = 0.005 for all penetrating brain injuries [PBIs]; OR 13.3 and p = 0.001 for gunshot wounds [GSWs]). Significant quantitative variables were higher SAH and IVH scores. An SAH score of 3 (area under the ROC curve [AUC] for all PBIs 0.72; AUC for GSWs 0.71) and an IVH score of 3 (AUC for all PBIs 0.65; AUC for GSWs 0.65) could be used as threshold values to suggest an arterial injury.
The risk factors identified may help radiologists suggest the possibility of arterial injury and prioritize neurointerventional consultation and potential DSA studies.
Vascular complications of penetrating brain injury: comparison of helical CT angiography and conventional angiography
Uttam K. Bodanapally, Kathirkamanathan Shanmuganathan, Alexis R. Boscak, Paul M. Jaffray, Giulia Van der Byl, Ashis K. Roy, David Dreizin, Thorsten R. Fleiter, Stuart E. Mirvis, Jaroslaw Krejza, and Bizhan Aarabi
The authors conducted a study to compare the sensitivity and specificity of helical CT angiography (CTA) and digital subtraction angiography (DSA) in detecting intracranial arterial injuries after penetrating traumatic brain injury (PTBI).
In a retrospective evaluation of 48 sets of angiograms from 45 consecutive patients with PTBI, 3 readers unaware of the DSA findings reviewed the CTA images to determine the presence or absence of arterial injuries. A fourth reader reviewed all the disagreements and decided among the 3 interpretations. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of CTA were calculated on a per-injury basis and in a subpopulation of patients with traumatic intracranial aneurysms (TICAs).
Sensitivity of CTA for detecting arterial injuries was 72.7% (95% CI 49.8%–89.3%); specificity, 93.5% (95% CI 78.6%–99.2%); PPV, 88.9% (95% CI 65.3%–98.6%); and NPV, 82.9% (95% CI 66.4%–93.4%). All 7 TICAs were correctly identified by CTA. Sensitivity, specificity, PPV, and NPV of CTA in detecting TICAs were 100%. To compare agreement with DSA, the standard of reference, confidence scores categorized as low, intermediate, and high probability yielded an overall effectiveness of 77.8% (95% CI 71.8%–82.9%).
Computed tomography angiography had limited overall sensitivity in detecting arterial injuries in patients with PTBI. However, it was accurate in identifying TICAs, a subgroup of injuries usually managed by either surgical or endovascular approaches, and non-TICA injuries involving the first-order branches of intracranial arteries.
Letter to the Editor: Cervical facet fractures
Nader S. Dahdaleh, Zachary A. Smith, Timothy E. Lindley, and Patrick W. Hitchon
Predictors of outcome in civilian gunshot wounds to the head
Bizhan Aarabi, Babak Tofighi, Joseph A. Kufera, Jeffrey Hadley, Edward S. Ahn, Carnell Cooper, Jacek M. Malik, Neal J. Naff, Louis Chang, Michael Radley, Ashker Kheder, and Ronald H. Uscinski
Civilian gunshot wounds to the head (GSWH) are often deadly, but some patients with open cranial wounds need medical and surgical management and are potentially good candidates for acceptable functional recovery. The authors analyzed predictors of favorable clinical outcome (Glasgow Outcome Scale scores of 4 and 5) after GSWH over a 24-month period.
The authors posited 2 questions: First, what percentage of civilians with GSWH died in the state of Maryland in a given period of time? Second, what were the predictors of favorable outcome after GSWH? The authors examined demographic, clinical, imaging, and acute care data for 786 civilians who sustained GSWH. Univariate and logistic regression analyses were used to analyze the data.
Of the 786 patients in this series, 712 (91%) died and 74 (9%) completed acute care in 9 trauma centers. Of the 69 patients admitted to one Maryland center, 46 (67%) eventually died. In 48 patients who were resuscitated, the Injury Severity Score was 26.2, Glasgow Coma Scale (GCS) score was 7.8, and an abnormal pupillary response (APR) to light was present in 41% of patients. Computed tomography indicated midline shift in 17%, obliteration of basal cisterns in 41.3%, intracranial hematomas in 34.8%, and intraventricular hemorrhage in 49% of cases. When analyzed for trajectory, 57.5% of bullet slugs crossed midcoronal, midsagittal, or both planes. Two subsets of admissions were studied: 27 patients (65%) who had poor outcome (25 patients who died and 2 who had severe disability) and 15 patients (35%) who had a favorable outcome when followed for a mean period of 40.6 months. Six patients were lost to follow-up.
Univariate analysis indicated that admission GCS score (p < 0.001), missile trajectory (p < 0.001), surgery (p < 0.001), APR to light (p = 0.002), patency of basal cisterns (p = 0.01), age (p = 0.01), and intraventricular bleed (p = 0.03) had a significant relationship to outcome. Multivariable logistic regression analysis indicated that GCS score and patency of the basal cistern were significant determinants of outcome. Exclusion of GCS score from the regression models indicated missile trajectory and APR to light were significant in determining outcome.
Admission GCS score, trajectory of the missile track, APR to light, and patency of basal cisterns were significant determinants of outcome in civilian GSWH.
Comparative effectiveness of surgical versus nonoperative management of unilateral, nondisplaced, subaxial cervical spine facet fractures without evidence of spinal cord injury
Bizhan Aarabi, Stuart Mirvis, Kathirkamanthan Shanmuganathan, Alexander R. Vaccaro, Cassandra J. Holmes, Noori Akhtar-Danesh, Michael G. Fehlings, and Marcel F. Dvorak
Facet joints are major stabilizers of cervical motion allowing for effortless and pain-free multidimensional cervical spine movements without significant linear or rotational translation, thus minimizing any chance for spinal cord or nerve root impingement. Unilateral, nondisplaced subaxial facet fractures do not meet the conventional criteria for spinal instability under physiological loads. Limited evidence indicates that even with no or minimal displacement, 20%–80% of these fractures fail nonoperative management. The risk factors for instability in isolated nondisplaced subaxial facet fractures remain uncertain. In this retrospective study of prospectively collected data, the authors attempted to identify the predictors of failure in the management of isolated, nondisplaced subaxial facet fractures admitted to their Level I trauma center over a 10-year period.
Demographic, clinical, imaging, and follow-up data for 25 patients with unilateral nondisplaced subaxial facet fractures who were managed surgically (n = 10) or nonoperatively (n = 15) were statistically analyzed.
The mean age of the patients was 38 years, 19 were male, and 21 of the fractures were the result of either motor vehicle accidents or falls. The mean motor score on the American Spinal Injury Association scale was 99.2, and the mean Subaxial Injury Classification (SLIC) severity score was 3 (operated 3.5, nonoperated 2.3). Allen mechanistic classification included 22 compressive-extension Stage 1 and 2 distractive-extension Stage 1 fractures. Subaxial facet fractures involved C-7 in 17 patients (68%), C-6 in 7 (28%), and C-3 in 1 (4%). The anatomical plane of fracture through the lateral mass was sagittal in 12 patients, axial in 8, and coronal in 3 patients. Nondisplaced floating lateral mass injuries were noted in 2 patients. The mean instability score, considering 7 components of the discoligamentous complex on MRI, was 3.2 (operated 3.6, nonoperated 3.0). Ten (40%) of 25 patients in this investigation did not have successful management, 9 in the nonoperated and 1 in the operated group (p = 0.018). Unsuccessful management was significantly greater in younger patients (p = 0.0008), possibly indicating selection bias (p = 0.07, Wilcoxon ranksum test). Fracture plane, instability, and SLIC scores did not play a significant role in treatment failure in this study.
In this study, surgery was superior to nonoperative management of isolated, nondisplaced, or minimally displaced subaxial cervical spine facet fractures.