151SProceedings of the NASS 22nd Annual Meeting / The Spine Journal 7 (2007) 1S–163S

the C3/4 disc level from neutral to flexion, canal diameter decreased with

an increasing disc degeneration. At the C7/T1 disc level from neutral to

extension, canal diameter increased with increasing disc degeneration.

CONCLUSIONS: Dynamic MRI is effective in demonstrating changes in

canal diameter of the C-spine on flexion and extension. Spinal canal diam-

eter increases with flexion and decreases with extension. These results re-

flect the importance of Dynamic MRI in detecting canal diameter changes

in patients enduring cervical stenosis, otherwise under estimated by tradi-

tional MRI. Although the reason is still unknown, this study shows that

disc degeneration in the uppermost and lowermost levels like C3-4 and

C7-T1 exerts more influences on canal diameter changes than in central

levels of the c-spine.

FDA DEVICE/DRUG STATUS: This abstract does not discuss or include

any applicable devices or drugs.

doi: 10.1016/j.spinee.2007.07.356

P148. Regulation of Osteoblast Lifespan in Osteoporotic Vertebral

Fractures

John Street1, Brian Lenehan2, Charles Fisher, MD3, Marcel Dvorak, MD,

FRCSC3; 1Vancouver General Hospital, Vancouver, British Columbia,

Canada; 2British Columbia, Canada; 3University of British Columbia,

Vancouver, British Columbia, Canada

BACKGROUND CONTEXT: Osteoporosis in vertebral insufficiency

fractures is characterized by pathological osteoblast cell death. This path-

ological apoptosis is associated with relative hypovascularity. Skeletal

injury in humans results in ‘angiogenic’ responses primarily mediated by

vascular endothelial growth factor(VEGF). Osteoblasts release VEGF

express receptors for VEGF in a differentiation dependent manner.

PURPOSE: This study investigates the putative role of VEGF in regulat-

ing the lifespan of primary human vertebral osteoblasts(PHOB) in vitro.

STUDY DESIGN/SETTING: Osteoblasts were cultured from human

biopsies and cell life cycle and apoptosis was examined in vitro.

PATIENT SAMPLE: Vertebral body bone biopsies were taken from 24

consecutive patients undergoing therapeutic vertebroplasty.

OUTCOME MEASURES: PHOB from osteoporotic vertebral fractures

were examined for in vitro cell life span and activity.

METHODS: PHOB were examined for VEGF receptors. Cultures were

supplemented with VEGF(0–50ng/mL), a neutralising antibody to VEGF,

mAB VEGF(0.3ug/mL) and Placental Growth Factor (PlGF), an Flt-1 re-

ceptor-specific VEGF ligand(0–100 ng/mL) to examine their effects on

mineralised nodule assay, alkaline phosphatase assay and apoptosis. The

role of the VEGF specific antiapoptotic gene target BCl2 in apoptosis

was determined.

RESULTS: PHOB from osteoporotic vertebral fractures expressed func-

tional VEGF receptors. VEGF 10 and 25 ng/mL increased nodule forma-

tion 2.3- and 3.16-fold and alkaline phosphatase release 2.6 and 4.1-fold

respectively while 0.3ug/mL of mAB VEGF resulted in approx 40% reduc-

tions in both. PlGF 50ng/mL had greater effects on alkaline phosphatase

release (103% increase) than on nodule formation (57% increase). 10ng/

mL of VEGF inhibited spontaneous and pathological apoptosis by

83.6% and 71% respectively, while PlGF had no significant effect. Pre-

treatment with mAB VEGF, in the absence of exogenous VEGF resulted

in a significant increase in apoptosis (14 vs 3%). BCl2 transfection gave

a 0.9% apoptotic rate. VEGF 10 ng/mL increased BCl2 expression 4 fold

while mAB VEGF decreased it by over 50%.

CONCLUSIONS: VEGF is a potent regulator of osteoblast life-span in

vitro. This autocrine feedback regulates survival of these cells, mediated

via the KDR receptor and expression of BCl2 antiapoptotic gene. This

study may offer a novel chemotherapeutic agent for the management

and prevention of vertebral osteoporosis.

FDA DEVICE/DRUG STATUS: This abstract does not discuss or include

any applicable devices or drugs.

doi: 10.1016/j.spinee.2007.07.357

P149. The Feasibility of Neuromonitoring for Cerebral Palsy

Scoliosis and the Outcome of Neurological Complications

Suken Shah, MD1, Paul Sponseller2, Mark Abel3, Peter Newton, MD4,

Daniel Sucato, MD5, Lynn Letko, MD6, Randal Betz, MD7; 1Wilmington,

DE, USA; 2Johns Hopkins University, Baltimore, MD, USA; 3University of

Virginia, Charlottesville, VA, USA; 4San Diego, CA, USA; 5Dallas, TX,

USA; 6Klinikum Karlsbad-Langensteinbach, Karlsbad-Langensteinbach,

Karlsbad-Langensteinbach, Germany; 7Temple University, Philadelphia,

PA, USA

BACKGROUND CONTEXT: The usefulness of intraoperative neuro-

physiologic monitoring in scoliosis surgery for patients with CP is ques-

tioned by some. The rate, severity and outcome of neurological injuries

during surgery in these patients are not well reported. Monitoring of

MEP and SSEP in these patients undergoing spinal deformity is feasible

and useful to detect impending neurologic deficits.

PURPOSE: The purposes of this study were 1) to study the feasibility and

reliability of intraoperative neurophysiologic monitoring (IONM) in pa-

tients with scoliosis due to CP and 2) determine the rate, nature and out-

come of neurological complications in spinal deformity surgery in these

patients.

STUDY DESIGN/SETTING: A multicenter database of 163 children

with CP and scoliosis who underwent surgery with minimum 2 year follow

up was reviewed retrospectively.

PATIENT SAMPLE: 121 patients with CP who underwent scoliosis sur-

gery with intraoperative neurophysiologic monitoring.

OUTCOME MEASURES: The rate, severity and outcome of neurologi-

cal injuries during surgery. Intraoperative MEP and SSEP.

METHODS: A multicenter database of 163 children with CP and scoliosis

who underwent surgery with minimum 2 year follow up was reviewed; 121

had IONM, and of those with complete records, 71% had good or fair po-

tentials that were useful during surgery, and 22% had IONM attempted and

abandoned due to poor baseline signals.

RESULTS: Seven patients (4.3%) had an adverse neurologic event, 5 in-

traoperative and 2 were noted postoperatively (both of these had no

IONM). All intraoperative events were detected by IONM with a decrease

from baseline MEP and SSEP. The treatment was typically a surgical

pause, elevation of BP, administration of methylprednisolone, and/or ad-

justment of instrumentation. All but one recovered fully over time (range:

immediately to 6 months postoperatively) The course of recovery was ac-

companied by increased spasticity and contractures. Of the two patients

with postoperative deficits noted 1-2 days after surgery, one had removal

of instrumentation for motor and sensory deficits, recovered and was re-in-

strumented, and the other was treated for a neurogenic bladder that recov-

ered after 4 months. No correlation to curve size, apex or EBL could be

identified with the numbers available. The patients who had IONM attemp-

ted and abandoned due to poor baseline signals were typically severely in-

volved spastic quadriplegic patients with MR. No postoperative deficits

were detected in patients with reliable baseline signals that were stable

throughout surgery (no false negatives).

CONCLUSIONS: The rate of neurologic complication in this population

of patients with CP undergoing spinal deformity surgery for scoliosis was

4.3%. IONM was feasible in 71% and provided reliable information re-

garding an impending neurologic deficit and was 100% specific. When

neurologic complications did occur, the prognosis was fair and improve-

ment was noted over time.

FDA DEVICE/DRUG STATUS: This abstract does not discuss or include

any applicable devices or drugs.

doi: 10.1016/j.spinee.2007.07.358

P150. Evolution of Thoracic Pedicle Screws in AIS over a Ten Year

Period: Are the Outcomes Better?

Suken Shah, MD1, Randal Betz, MD2, Peter Newton, MD3,

David Clements, MD4, Harry Shufflebarger, MD5, Thomas Lowe, MD6;1Wilmington, DE, USA; 2Temple University, Philadelphia, PA, USA; 3San