Awards Abstracts 1

Quantitative MRI assessments correlate with neurological outcome in patients with acute cervical traumatic spinal cord injury: A prospective multicenter study in 100 consecutive patients with independent review and statistical modeling
Julio C. Furlan, M.D., M.B.A., Ph.D.1; Firoz Miyanji, M.D.2; Bizhan Aarabi, M.D.3; Paul Arnold, M.D., F.A.C.S.4; Michael G. Fehlings, M.D., Ph.D., F.R.C.S.C.1
1Krembil Neuroscience Centre, Spinal Program, Toronto Western Hospital, University Health Network, and Department of Surgery, Division of Neurosurgery, University of Toronto, Toronto, ON, Canada; 2Children's Hospital of San Diego, San Diego, CA, USA; 3Department of Neurosurgery, University of Maryland, Baltimore, MD, USA; 4Department of Neurosurgery, University of Kansas, KS, USA.

Objective:
This study examines 10 MRI assessments as potential predictors of patients’ neurological status and outcome at long-term follow-up.

Design:
Prospective multicenter cohort study.

Participants/Methods:
We included 100 consecutive patients with complete SCI (ASIA A), patients with incomplete SCI (ASIA B-D), and as controls patients with cervical trauma and a normal neurological assessment (ASIA E) who had a MRI study within 24-48 hours post-trauma.

Results:
There were 79 males and 21 females with mean age of 49 years (17-96 yrs). Incomplete SCI (51%) was more often than complete SCI (26%) and normal neurological assessment (22%) on admission. Mean follow-up was 7 months (1-35 months). Mean maximum canal compromise (MCC), maximum spinal cord compression (MSCC) and length of hemorrhage (LOH) were significantly greater in patients with complete SCI than in individuals with incomplete SCI. While sex was a significant covariate for MCC, age was significantly correlated with MSCC. Neither age nor sex was significantly associated with LOH. The frequency of intramedullary hemorrhage, cord edema, swelling and soft tissue injury at injury site (but not canal stenosis and disc herniation) was significantly higher in patients with complete SCI. Using stepwise multivariable regression, all 10 qualitative and quantitative elements were tested for prediction of ASIA motor scores on admission and at last followup visit. The best model for prediction of the baseline ASIA motor score has MCC, MSCC and swelling. The best model for predicting unadjusted follow-up neurological evaluation has MSCC, hemorrhage and swelling. The best model for prediction of follow-up ASIA motor score adjusted for baseline ASIA motor score includes hemorrhage and swelling.

Conclusion:
MRI is a useful tool in prognosticating the potential for neurological recovery. The severity of spinal cord compression, extent of hemorrhage and the degree of T2 signal change are strong predictors of outcome after traumatic cervical SCI.

Support:
This work was supported by funds from Medtronic Inc (Spine Trauma Study Group), the Lawson Fellow-Neurology from The Toronto General & Western Hospital Foundation (JCF) and the Krembil Chair in Neural Repair and Regeneration (MGF).

A Biomechanical Evaluation of Segmental Occipito-Atlanto-Axial Fixation Techniques with Respect to Risk to the Vertebral Artery
Jonathan T. Nassos, M.D.1,2; Alexander J. Ghanayem, M.D.1,2; Rick Sasso, M.D.3; Michael Nicolakis, M.D.2; Leonard I. Voronov, M.D. Ph.D.2; Anthony Rinella, M.D.1,2; Gerard Carandang, M.S.2; Avinash G. Patwardhan, Ph.D.1,2
1Loyola University Medical Center, Maywood, IL; 2Department of Veterans Affairs, Edward Hines Jr. VA Hospital, Hines, IL; 3Indiana Spine Group, Indianapolis, IN

Objective:
To evaluate the construct stability of three different segmental occipito-atlanto-axial fixation techniques, each of which place a different degree of risk to the vertebral artery.

Design:
This is a human cadaveric biomechanical study using a known instability model requiring occiptio-atlanto-axial stabilization.

Participants/methods:
Six cadaveric occipito-cervical spines (Occiput to C3) were prepared for test by cleaning off the soft tissue but preserving all ligaments. After testing the intact spines in flexion/extension, lateral bending, and axial rotation, instability was created by transecting the transverse and alar ligaments. The spines were instrumented segmentally (Vertex, Medtronic, Memphis TN) from the occiput to C2 via three different techniques which varied in the attachment to C2. All spines had 6 screws placed into the occiput, and C1 lateral mass screws. The 3 variations used in C2 were: 1) C2 crossing laminar screws, 2) C2 pedicle screws, 3) C1-C2 transarticular screws. The C1 lateral mass screws were removed prior to placement of the C1-C2 transarticular screws. Range of motion was tested for each and compared to intact as well as between each construct.

Results:
All three techniques significantly decreased range of motion compared to the intact specimen (P<0.05). There was no statistical difference among the three fixation methods (P>0.05). However, the fixation technique using C2 crossing laminar screws demonstrated a trend toward increased range of motion compared to the other two techniques, particularly in lateral bending.

Conclusion:
Occipito-atlanto-axial fixation techniques using C2 crossing laminar screws, C2 pedicles screws, and C1-2 transarticular screws offer similar biomechanical stability. Using the C2 crossing laminar screw technique may offer an advantage to the other techniques due to the elimination of the risk to the vertebral artery during C2 screw placement.

Support:
This project was funded by a resident research grant from Medtronic (Memphis TN)

Neuroplasticity and Recovery of Hindlimb Function in Spinal Cord Hemisected Rats Mediated by Peripheral Nerve Rerouting and Intramuscular bFGFApplication
Konya D, Liao WL, Choi H, Yu D, Newton KM, King AM, Pamir MN, Black PMcL, Teng YD.
Neurosurgery, Harvard/Brigham and Women Hosp, Boston, MA;
SCI Research Laboratory, VA Boston Healthcare System, Boston, MA;
Physical Med and Rehab, Harvard/Spaulding Rehab Hosp., Boston, MA;
Neurosurgery, Marmara University, Istanbul Turkey

Modest degrees of functional recovery after spinal cord injury (SCI) have been reported following the rerouting of intercostal nerves originating proximal to injured spinal cord segments to distal neuromuscular targets (i.e., neurotization). Although the various surgical procedures have been well described in the clinical and experimental literature, the mechanisms related to this recovery, as yet, are essentially unknown. To test the hypothesis that neurotization would result in neuroplasticity of the spinal cord distal to the SCI and enhance functional restoration, we developed a rat model in which the T12 intercostal nerve was rerouted and anastomosed to the ipsilateral L3 nerve root 1-4 weeks after T13 spinal cord hemisection. Structural integrity of the nerve anastomosis was demonstrated using electromyography and redundant axonal tracing (e.g., fluorogold, DiI and biotinylated dextran amine [DBA]). Starting 5 weeks after anastomosis (i.e., ~6 weeks post hemisection), neurobehavioral function, as assessed by open field locomotion, foot print analyses and sciatic index, of animals receiving neurotization 7-10 days post SCI recovered robustly to levels statistically different from the control animals. Additionally, their functional outcome was further improved with enhanced physical activity therapy through increased locomotion distance nurtured by enlarged/enriched cage. In contrast, hindlimb deficits in T13 hemisected controls with sham neurotization remained largely unchanged during the entire study period. We also examined the neuroplasticity of injured spinal cords with BrdU labeling of proliferating cells, immunocytochemistry for detecting trophic factors, axonal tracing and neurocircuitry reorganization signals such as synaptophysin. Our preliminary results suggest that enhanced progenitor cell proliferation, axonal and synaptic reorganization and increased survival of nascent neuronal cells at the SCI site of neuronitized animals may underlie the observed hindlimb locomotion recovery. Moreover, the efficacy of the neurorerouting and the subsequent plasticity and functional recovery appear to be enhanced by local bFGF application to the innervated muscles. Overall, these data support our hypothesis that peripherally bridged neuromuscular activity through rerouting and anastomosing a nerve proximal to a SCI to a site distal to the SCI stimulates neuroplasticity in the distal spinal cord, resulting in significantly augmented functional improvement.

Objective:
Determine the long-term history of bladder management in spinal cord injury(SCI) utilizing longitudinal data from the National Spinal Cord Injury Statistical Center(NSCISC) and the University of Alabama at Birmingham(UAB) databases.

Design:
Datasets from the NSCISC and UAB were examined to determine method of bladder management at time of discharge and at 5, 10, 15, 20, and 25 years post injury. Management categories included intermittent catheterization(CIC), condom catheter drainage, normal voiding, foley, suprapubic catheter, Crede’ voiding, and”other”. Incidence of urinary stone formation and renal function as determined by a renal scan were assessed aamong the various bladder managements.

Participants/Methods:
The NSCISC database included information on 16,648 traumatic SCI patients and the UAB database included 2, 200 patients. 82% were male and 18% female. Bladder management, complications, and renal function were assessed at all of the above time points post-injury.

Results:
At discharge, 43% of male and 42.4% of female patients performed intermittent catheterization. At 25 years post-injury, 12.9% of males and 24.2% of females performed intermittent catheterization with concommitant increases primarily in indwelling catheterization as a method of bladder management. Relative risk of kidney stone formation over time greater than 2 years post injury increased modestly (2.0-2.5%) for intermittent catheter use, condom or indwelling catheter use versus catheter free status, while the relative risk of bladder stone formation rose to 18.8% for indwelling catheters compared to 6.2% for intermittent catheterization and 2.5% for condom catheter use. No clinically meaningful change in renal function over time was observed among patients using different methods of bladder management up to 25 years post injury.

Conclusions:
Many reasons contribute to changes in bladder management over time including prevailing rehabilitation philosophy, patient preference, and complications of bladder management. As time progresses post injury, fewer patients continue with CIC and more adopt indwelling catheters. There is however, only a modestly increased risk of stone formation with indwelling catheters with bladder stones most common. No statistically significant differences in renal function were seen among the various methods of bladder management.

Objective:
Determine the effects of menopause following SCI (ASIA complete and non ambulatory incomplete) by comparing osteoporosis, spine changes, pain and function, hormone levels, metabolic parameters, and quality of life in post-menopausal women, with and without SCI and age/time post-injury equivalent men with SCI.

Design:
Cross-sectional study; Statistical analysis by student t test, chi square and ANOVA

Participants/Methods:
Study participants included women with SCI (WSCI) who had undergone menopause at least 2 years prior. Control participants included 1) post-menopausal, able-body women (ABW) matched by age and DEXA scans (“normal”, “osteopenia”, or “osteoporosis”); and 2) men with SCI (MSCI) matched by a range of time post-injury. All participants who consented to the study received DEXA scans of spine, femur, and hip, metabolic lab profiles, spine Xrays, mobility and functional questionnaires and Life Satisfaction Tools. Men and Women with SCI were also given the Wheelchair User’s Shoulder Pain Index (WUSPI) test. Statistical Analysis was performed to compare groups.

Results:
30 participants have completed testing. 24 participants (=8 completed triads: WSCI+ABW+MSCI) were analyzed. Mean ages were 51.25 years for WSCI, 54.2 for ABW, 52.1 for MSCI. (p>.05,n.s.). Mean ages at menopause were 43.36 for WSCI and 45.38 for ABW (p>.05,n.s.). Mean years post injury were 21 years for WSCI and 19 for MSCI (n.s.). There was statistical difference of increased osteoporosis at the hips of the WSCI followed by MSCI then ABW. No significant difference was found for DEXA values at the lumbar spine and femur. WSCI had significantly higher (p<.05) pain and functional limitations on the WUSPI compared to MSCI and significantly more (p<.05) difficulties with Activities of Daily Living compared to ABW. Significant (p<.05) metabolic differences were: WSCI had higher fasting glucose followed by ABW and MSCI controls; WSCI had highest Total and LDL Cholesterol than ABW and MSCI ; and WSCI had higher estradiol than ABW. There were no statistical differences in Total Life Satisfaction Scale between any group.

Conclusion:
The impact of menopause and aging in women after SCI is significant and unique compared to their Able body post-menopausal women and aging post-SCI male counterparts.

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