RESULTS: The average age (ProDisc-C539 y.o., ACDF542 y.o.) and av-

erage weight (ProDisc-C5170 lb, ACDF5169 lb) were similar at time of

surgery. The operative time (ProDisc-C5122617 min, ACDF5134622)

and blood loss (ProDisc-C595637 ml, ACDF563617 ml) also showed

no differences. The VAS scores for neck pain and frequency as well as

arm pain and frequency showed no statistical differences between the

two treatments. However, both treatments showed marked improvement

in radiculopathy versus preoperative state. Postoperative radiographs show

restoration of disc height with maintenance of range of motion. Three Pro-

Disc-C patients have presented at follow-up with heterotopic ossification at

the surgical level. There were no intraoperative complications and no

device-related failures.

CONCLUSIONS: Our current results demonstrate Prodisc-C total disc re-

placement alleviates pain and improves function based on neurologic

symptoms and signs similar to the control ACDF with postoperative radio-

graphs demonstrating motion. Long-term review of dynamic radiographs

will be needed to track gross motion preservation as well as incidence

of adjacent segment disease and instability.

FDA DEVICE/DRUG STATUS: ProDisc-C: Investigational/not

approved.

CONFLICT OF INTEREST: No conflicts.

doi: 10.1016/j.spinee.2006.06.359

Electronic Poster Displays

P151. The Osteoinductive Properties of Nell-1 in a Rat Spinal Fusion

Model

Steven Lu1, Xinli Zhang2, Kang Ting3, Jeffrey Wang, MD4; 1Cedars Sinai

Neonatology, West LA, CA, USA; 2University of California, Los Angeles,

CA, USA; 3University of California, Los Angeles, Los Angeles, CA, USA;4University of California, Los Angeles, Santa Monica, CA, USA

BACKGROUND CONTEXT: Recombinant growth factors BMP-2 and

BMP-7 are currently approved for human use but are associated with var-

ious adverse effects including ectopic bone formation and local inflamma-

tory reaction. Demineralized bone matrix with growth factor appears to

improve spinal fusion rates in animal models. As supraphysiolgic doses

of BMP are required, the production cost alone of BMP is a distinct disad-

vantage to its clinical use. Nell-1 [Nel-like molecule-1; Nel (a protein

strongly expressed in neural tissue encoding epidermal growth factor like

domain)] is a novel secretory molecule that was initially discovered to be

overexpressed during premature bone formation in calvarial sutures of in-

fants with craniosynostosis. Previous studies show that Nell-1 accelerates

osteogenic differentiation in vitro and bone formation in vivo. We hypoth-

esize that Nell-1 works downstream from bone morphogenic proteins

(BMPs) and Core-binding Factor A. Therefore it may potentially be a more

selective alternative growth factor that can promote osteoinduction.

PURPOSE: Our primary aim was to assess if adenoviral gene therapy

with Nell-1 combined with demineralized bone matrix can improve spinal

fusion in a rat model. Ideally, this would also provide a low cost method of

delivering specific growth factors to areas requiring osteoinduction.

STUDY DESIGN/SETTING: Two groups of 24 athymic rats underwent

intertransverse process spinal fusion at L4-L5 and implanted with a demin-

eralized bone matrix carrier containing either adenovirus coding for Nell-1

(Ad-Nell-1) or control, Lac Z (Ad-Lac Z). Four rats were sacrificed at 4

weeks to evaluate for bone development at an earlier time point. The rest

of the 20 rats were sacrificed at 6 weeks for evaluation of spinal fusion.

PATIENT SAMPLE: Not applicable. Animal study.

OUTCOME MEASURES: Not applicable. Animal study.

METHODS: Faxitron radiographs were acquired for all animals at 2, 4,

and 6 weeks. Manual palpation by three independent observers was per-

formed after the animals were sacrificed at 6 weeks. Three-dimensional re-

construction of high-resolution MicroCT by uCT40 was obtained on all

spine samples. Coronal sections of involved spine segments were analyzed

for new bone formation by H&E and Masson trichrome staining on decal-

cified tissue. The expression of beta-galactosidase and Nell1 was con-

firmed in corresponding new bone tissue by immunohistochemistry. In

situ expression of bone sialoprotein and BMP-7 was examined by immu-

nohistochemistry for evaluation of bone maturity.

RESULTS: Please refer to Table 1 for results of manual palpation, microCT,

and histology. All differences achieved statistical significance. Based on his-

tology at 4 weeks, more endochondrial bone formation was recognized in

the Ad-Nell1 samples and more mature trabecular bone was seen at 6 weeks.

Immunohistochemistry showed increased BSP and BMP7 expression in

cells adjacent to the demineralized bone particles in the Ad-Nell1 group.

CONCLUSIONS: This adenoviral model demonstrated the ability of

Nell1 to successfully promote new bone regeneration with spinal fusion

in rats as evaluated by all methodology. More mature bone formation oc-

curs near the transverse process in the Ad-Nell1 group. This may indicate

increased specificity of Nell’s osteoinductive function toward its intended

target.

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

any applicable devices or drugs.

CONFLICT OF INTEREST: No conflicts.

doi: 10.1016/j.spinee.2006.06.362

P152. How Do You Know When a Patient Is Better?

John Mayer, DC, PhD, Vert Mooney, MD, Joe Verna, DC; U.S. Spine &

Sport Foundation, San Diego, CA, USA

BACKGROUND CONTEXT: The demand for valid, efficient, and cost-

effective outcome instruments to assess efficacy of treatment for spinal dis-

orders is growing. Various instruments are used for this purpose, including

self-report tools that assess physical functioning and pain intensity, and

physical performance measures, such as muscular strength tests. Whether

or not multiple tests are needed to document efficacy of treatment is

unknown.

PURPOSE: The purpose of this study was to evaluate the relationships

among various measures used to document outcomes of physical treatment

of chronic spinal disorders.

STUDY DESIGN/SETTING: A retrospective cohort study was con-

ducted at an outpatient physical rehabilitation center.

PATIENT SAMPLE: Patients (n5137) with cervical (n540), lumbar

(n569), or a combination of cervical and lumbar (n528) chronic muscu-

loskeletal disorders who were enrolled in a restorative exercise program

participated in this study. The majority (67%) of patients were treated

for work-related injuries.

OUTCOME MEASURES: Self-reported physical functioning was as-

sessed with the 0-444 global rating of perceived capacity score from the

Multidimensional Task Ability Profile (MTAP), which was cross-walked

to a physical demand characteristic level of work. The MTAP is a comput-

erized pictorial activity and task sort with items consisting of drawings and

captions depicting progressively demanding functional activities of daily

living and work. Pain intensity was assessed with a 10cm visual analog

scale. Isometric cervical extension strength and/or lumbar extension

strength was assessed using dynamometry.

METHODS: Patients underwent a restorative exercise program that con-

sisted of supervised progressive resistance, coordination, flexibility, and

functional exercises performed 2–3 times per week. Outcomes were as-

sessed at baseline and a clinical meaningful follow-up time point while en-

rolled in the program (time period between baseline and follow-up tests:

(44618.9 days, range 17–98 days). Pearson correlation coefficients were

calculated to compare the outcome measures with one another. For each

measure, t tests were performed to compare scores at baseline and

follow-up.

RESULTS: At baseline, significant (p!.05) weak to moderate correlations

were noted among the outcome measures (MTAP and cervical strength:

r5.57. MTAP and lumbar strength: r5.37. MTAP and pain intensity:

r5–.48. Cervical strength and pain intensity: r5–.30. Lumbar strength

156S Proceedings of the NASS 21st Annual Meeting / The Spine Journal 6 (2006) 1S–161S