William D. Freeman, Jason Sebesto and Rabih G. Tawk
Andrew L. Freeman, William J. Camisa, Glenn R. Buttermann and James R. Malcolm
This study was undertaken to quantify the in vitro range of motion (ROM) of oblique as compared with anterior lumbar interbody devices, pullout resistance, and subsidence in fatigue.
Anterior and oblique cages with integrated plate fixation (IPF) were tested using lumbar motion segments. Flexibility tests were conducted on the intact segments, cage, cage + IPF, and cage + IPF + pedicle screws (6 anterior, 7 oblique). Pullout tests were then performed on the cage + IPF. Fatigue testing was conducted on the cage + IPF specimens for 30,000 cycles.
No ROM differences were observed in any test group between anterior and oblique cage constructs. The greatest reduction in ROM was with supplemental pedicle screw fixation. Peak pullout forces were 637 ± 192 N and 651 ± 127 N for the anterior and oblique implants, respectively. The median cage subsidence was 0.8 mm and 1.4 mm for the anterior and oblique cages, respectively.
Anterior and oblique cages similarly reduced ROM in flexibility testing, and the integrated fixation prevented device displacement. Subsidence was minimal during fatigue testing, most of which occurred in the first 2500 cycles.
Bahram Chehrazi, Franklin C. Wagner Jr., William F. Collins Jr. and Daniel H. Freeman Jr.
✓ A scale has been developed for assessment of the severity of spinal cord injury and the prognosis for recovery. Based on neurological examination, this scale employs numerical grading of selected functions below the level of the injury. The scale is adaptable to prospective as well as retrospective studies, and provides a reliable estimation of prognosis and, therefore, a means of comparing the effectiveness of differing treatment modalities.
In relation to a group of 37 patients with cervical spinal cord injury treated under one protocol and assessed within 24 hours and again at 1 year from injury, a descriptive model of the patterns of recovery has been obtained. Relative recovery of the initial deficit measured as a “percentage recovery ratio” is presented as an analytical tool for comparison of effectiveness of different methods of therapy.
John C. Drummond and Piyush M. Patel
Philipp Taussky, Brandon O'Neal, Wilson P. Daugherty, Sothear Luke, Dallas Thorpe, Robert A. Pooley, Clay Evans, Ricardo A. Hanel and William D. Freeman
Near-infrared spectroscopy (NIRS) offers noninvasive bedside measurement of direct regional cerebral arteriovenous (mixed) brain oxygenation. To validate the accuracy of this monitoring technique, the authors analyzed the statistical correlation of NIRS and CT perfusion with respect to regional cerebral blood flow (CBF) measurements.
The authors retrospectively reviewed all cases in which NIRS measurements were obtained at a single, academic neurointensive care unit from February 2008 to June 2011 in which CT perfusion was performed at the same time as NIRS data was collected. Regions of interest were obtained 2.5 cm below the NIRS bifrontal scalp probe on CT perfusion with an average volume between 2 and 4 ml, with mean CBF values used for purposes of analysis. Linear regression analysis was performed for NIRS and CBF values.
The study included 8 patients (2 men, 6 women), 6 of whom suffered subarachnoid hemorrhage, 1 ischemic stroke, and 1 intracerebral hemorrhage and brain edema. Mean CBF measured by CT perfusion was 61 ml/100 g/min for the left side and 60 ml/100 g/min for the right side, while mean NIRS values were 75 on the right and 74 on the left. Linear regression analysis demonstrated a statistically significant probability value (p < 0.0001) comparing NIRS frontal oximetry and CT perfusion–obtained CBF values.
The authors demonstrated a linear correlation for frontal NIRS cerebral oxygenation measurements compared with regional CBF on CT perfusion imaging. Thus, frontal NIRS cerebral oxygenation measurement may serve as a useful, noninvasive, bedside intensive care unit monitoring tool to assess brain oxygenation in a direct manner.
Neil Haranhalli, Nnenna Mbabuike, Sanjeet S. Grewal, Tasneem F. Hasan, Michael G. Heckman, William D. Freeman, Vivek Gupta, Prasanna Vibhute, Benjamin L. Brown, David A. Miller, Babak S. Jahromi and Rabih G. Tawk
The role of CT perfusion (CTP) in the management of patients with acute ischemic stroke (AIS) remains a matter of debate. The primary aim of this study was to evaluate the correlation between the areas of infarction and penumbra on CTP scans and functional outcome in patients with AIS.
This was a retrospective review of 100 consecutively treated patients with acute anterior circulation ischemic stroke who underwent CT angiography (CTA) and CTP at admission between February 2011 and October 2014. On CTP, the volume of ischemic core and penumbra was measured using the Alberta Stroke Program Early CT Score (ASPECTS). CTA findings were also noted, including the site of occlusion and regional leptomeningeal collateral (rLMC) score. Functional outcome was defined by modified Rankin Scale (mRS) score obtained at discharge. Associations of CTP and CTA parameters with mRS scores at discharge were assessed using multivariable proportional odds logistic regression models.
The median age was 67 years (range 19–95 years), and the median NIH Stroke Scale score was 16 (range 2–35). In a multivariable analysis adjusting for potential confounding variables, having an infarct on CTP scans in the following regions was associated with a worse mRS score at discharge: insula ribbon (p = 0.043), perisylvian fissure (p < 0.001), motor strip (p = 0.007), M2 (p < 0.001), and M5 (p = 0.023). A worse mRS score at discharge was more common in patients with a greater volume of infarct core (p = 0.024) and less common in patients with a greater rLMC score (p = 0.004).
The results of this study provide evidence that several CTP parameters are independent predictors of functional outcome in patients with AIS and have potential to identify those patients most likely to benefit from reperfusion therapy in the treatment of AIS.
Results of the National Acute Spinal Cord Injury Study
Michael B. Bracken, Mary Jo Shepard, Karen G. Hellenbrand, William F. Collins, Linda S. Leo, Daniel F. Freeman, Franklin C. Wagner, Eugene S. Flamm, Howard M. Eisenberg, Joseph H. Goodman, Phanor L. Perot Jr., Barth A. Green, Robert G. Grossman, John N. Meagher, Wise Young, Boguslav Fischer, Guy L. Clifton, William E. Hunt and Nathan Rifkinson
✓ A multi-center double-blind randomized clinical trial was conducted by the National Acute Spinal Cord Injury Study Group to examine the efficacy of high-dose methylprednisolone (1000-mg bolus and 1000 mg daily thereafter for 10 days) compared with that of a standard dose (100-mg bolus and 100 mg daily for 10 days). No significant difference was observed in neurological recovery of motor function, pinprick response, or touch sensation 1 year after injury between the two treatment groups, after adjustment for other potentially confounding factors. Analyses that specifically took into account the patients' total steroid dose and relative weight confirmed the lack of a steroid treatment effect. The case fatality rate was 10.7% during the 1st year after injury, and this was not associated with the steroid treatment protocol or the patient's gender. Deaths did occur significantly more frequently among patients who were completely (15.3%) and partially (8.6%) plegic than among those who were paretic (2.5%, p = 0.0005), and among patients aged 50 years or older (38.6%, p = 0.0001).