70S Proceedings of the NASS 24th Annual Meeting / The Spine Journal 9 (2009) 1S–205S

Charite disc compared to the more constrained ProDisc-L disc.

% Signifies significant difference from the fusion condition$ Signifies signifcant difference between the ProDisc-L and Maverick condition

Flexion + Extension Left + Right Lateral Bending Left + Right Axial Rotation

Maverick

-1.00 0.00 1.00 2.00 3.00

MS

U

Normalized to Harvested

%

%

%

%

%

$

Charite

-1.00 0.00 1.00 2.00 3.00

L1-L2

L2-L3

L3-L4

L4-L5

L5-S1

MS

U

Normalized to Harvested

%

%

%

%

Fusion

-1.00 0.00 1.00 2.00 3.00

L1-L2

L2-L3

L3-L4

L4-L5

L5-S1

MS

U

Normalized to Harvested

ProDisc-L

-1.00 0.00 1.00 2.00 3.00

L1-L2

L2-L3

L3-L4

L4-L5

L5-S1

MS

U

Normalized to Harvested

%

%

Maverick

-1.00 0.00 1.00 2.00 3.00

L1-L2

L2-L3

L3-L4

L4-L5

L5-S1

MS

U

Normalized to Harvested

%

%

Charite

-1.00 0.00 1.00 2.00 3.00

L1-L2

L2-L3

L3-L4

L4-L5

L5-S1

MS

U

Normalized to Harvested

%

%

%

Fusion

-1.00 0.00 1.00 2.00 3.00

L1-L2

L2-L3

L3-L4

L4-L5

L5-S1

MS

U

Normalized to Harvested

ProDisc-L

-1.00 0.00 1.00 2.00 3.00

L1-L2

L2-L3

L3-L4

L4-L5

L5-S1

MS

U

Normalized to Harvested

%

%

Maverick

-1.00 0.00 1.00 2.00 3.00

L1-L2

L2-L3

L3-L4

L4-L5

L5-S1M

SU

Normalized to Harvested

%

%

Charite

-1.00 0.00 1.00 2.00 3.00

L1-L2

L2-L3

L3-L4

L4-L5

L5-S1

MS

U

Normalized to Harvested

%

Fusion

-1.00 0.00 1.00 2.00 3.00

L1-L2

L2-L3

L3-L4

L4-L5

L5-S1

MS

U

Normalized to Harvested

ProDisc-L

-1.00 0.00 1.00 2.00 3.00

L1-L2

L2-L3

L3-L4

L4-L5

L5-S1

MS

U

Normalized to Harvested

%

%

%

%

$

Ped

icle S

crew

F

ixatio

nC

harite

Maverick

Pro

Disc-L

Figure. Percent Contribution of MSU Rotations.

FDA DEVICE/DRUG STATUS: ProDisc-L Disc: Approved for this indi-

cation; Charite Disc: Approved for this indication; Maverick Disc: Inves-

tigational/Not approved.

doi: 10.1016/j.spinee.2009.08.163

135. Do Self Reported Health Outcomes in Adult Spinal Deformity

Patients Correlate with Spino-Pelvic Geometrics?

Gang Li, MD1, Weishi Li2, Peter Passias, MD2, Michal Kozanek, MD3,

Shenglin Wang, MD2, Shaobai Wang, MD4, Frederick L Mansfield, MD2,

Brian Grottkau, MD2, Guoan Li, MD2, Zhongjun Liu, MD5,

Kirkham Wood, MD1; 15Massachusetts General Hospital/Harvard Medical

School, Boston, MA, USA; 2Boston, MA, USA; 3Massachusetts General

Hospital, Boston, MA, USA; 4Cambridge, MA, USA; 5Peking University

Third Hospital, Beijing, China

BACKGROUND CONTEXT: It has been increasingly recognized that

the study of sagittal balance should include pelvic geometrics and a corre-

lation between them has been demonstrated. Pelvic incidence (PI) deter-

mines lumbar lordosis and is a positional parameter reflecting

compensation to spinal deformity.

PURPOSE: The purpose of this study was to validate the correlation be-

tween self reported health outcomes (SRS22, EQ5D, ODI and SF12) and

spino-pelvic parameters (PI, PT5pelvic tilt and SS5sacral slope)) in

a population with adult deformity and also to evaluate the correlation with

the C7 plumb line (C7PL).

STUDY DESIGN/SETTING: This was a retrospective radiographic and

clinical analysis.

PATIENT SAMPLE: 76 adult spinal deformity patients (9 male and 67

female, average age 51.1 years) with minimum 3 years follow-up.

OUTCOME MEASURES: Radiological assessment.

METHODS: Full-length radiographs of the spine and pelvis were ob-

tained for all patients. The spino-pelvic parameters included PI, PT, SS

and C7PL; the self reported health outcome instruments included four

questionnaires: SRS22, EQ5D, ODI and SF12. Correlation analysis be-

tween radiographic spino-pelvic parameters and the four questionnaires

outcomes was assessed.

RESULTS: Correlation analysis revealed no significance related to coro-

nal plane geometrics. Significant sagittal plane parameter correlations were

identified. PI and PT correlated with: SRS22 (appearance, activity, and to-

tal score), EQ5D, ODI, and SF12 (PCS) with the correlation coefficients

ranged from 0.48r0.56 (p!0.001) but SS. The C7PL distance revealed sig-

nificant correlation with the four questionnaires outcomes (0.29r0.46,

p!.0001).

CONCLUSIONS: This study validates that spino-pelvic geometrics mea-

sured through PI correlate with the self reported health outcomes in certain

cohorts of adult deformity patients. High values of PI (PT) indicate a com-

pensatory pelvic retroversion for sagittal spinal alignment. This study also

demonstrates significant C7PL correlation with the four questionnaires

outcomes during follow-up. The evaluation of certain spino-pelvic geomet-

rics can be utilized as predictors of the outcomes in adult scoliosis patients

following treatment. Additionally, findings presented here highlight the

importance of assessing spino-pelvic alignment to evaluate the prognosis

of adult spinal deformity patients.

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

any applicable devices or drugs.

doi: 10.1016/j.spinee.2009.08.164

136. In Vivo Response to Synthetic Bone Graft Substitutes

in a Preclinical Posterolateral Fusion Model

William Walsh, PhD1, Ronald Hill, PhD2, William Lloyd3,

Nicky Bertollo, PhD4, Tsuyoshi Shinoda, MD4, Alban Merger, MD4,

Rema Oliver, PhD1, Yan Yu, MD, PhD1; 1University of New South Wales,

Sydney, New South Wales, Australia; 2Pioneer Surgical, Greenville, NC,

USA; 3Greenville, NC, USA; 4University of New South Wales, Randwick,

New South Wales, Australia

BACKGROUND CONTEXT: Synthetic bone grafts are used to augment

or even replace autograft by surgeons in spinal fusion procedures. Improv-

ing the biological response to synthetic grafts could result in better clinical

outcomes and a reduction in post operative morbidity.

PURPOSE: This study compared the response of two synthetic bone graft

substitutes in combination with autograft and bone marrow aspirate

(BMA) to autograft and BMA in posterolateral spinal fusion in rabbits.

We hypothesized that the combination of the synthetic materials with au-

tograft and BMA could be an alternative to autograft and BMA.

STUDY DESIGN/SETTING: Animal model (in vivo).

PATIENT SAMPLE: 24 New Zealand White Rabbits, 6 months old

OUTCOME MEASURES: Scanning electron microscopy (SEM), Faxi-

tron radiographs, computed tomography (CT), tensile mechanical testing,

and histology.

METHODS: A single-level posterolateral inter-transverse process fusion

adjacent to the vertebral body was performed bilaterally at L5-L6. Two

synthetic bone grafts were tested; nanocrystalline hydroxyapatite with

a collagen-dextran bioscaffold and a commercially available Si substituted

HA. 1.5 cc of corticocancellous bone graft was harvested from the iliac

crests, morselized and mixed with the synthetic materials (50/50). Bone

marrow aspirate (BMA) (2-3mls) from the proximal tibia was mixed with

grafts prior to placement between the decorticated surfaces of the trans-

verse processes. The autograft group included BMA with the bone chips.

Animals were euthanized after 12 weeks (n58 per group). Radiographs

and CT’s were graded in a blinded fashion to assess implant resorption,

new bone formation and fusion. Tensile stiffness, peak load and energy

were measured and statistically analyzed using ANOVA with multiple post

hoc Games Howell (P!0.05). Histology was evaluated in blinded fashion

at the host bone interface and fusion mass center.

RESULTS: The nanocrystalline HA had a surface area 200 x greater than

the Si substituted graft. As a result of HA in the synthetic material test

71SProceedings of the NASS 24th Annual Meeting / The Spine Journal 9 (2009) 1S–205S

groups radiographic fusion could not be assessed. However, new bone for-

mation was noted within all implant sites at 12 weeks. A continuous fusion

mass was present radiographically in 12/16 sites in the autograft group. CT

however demonstrated fusion masses in the synthetic groups and con-

firmed radiograhic findings of the autograft group. New bone was observed

adjacent to host bone and within the synthetic grafts and autograft. Tensile

mechanical testing revealed that the combination of nanocyrstalline HA

and bioscaffold was superior to the Si substituted HA graft (P!0.05),

but equivalent to autograft. Autograft was not statistically superior to the

Si substituted graft. Histology demonstrated new bone ingrowth and on-

growth on the hydroxyapatite of the synthetic grafts. No foreign body re-

sponse was noted to either material.

Figure 1. Scanning electron microscopy of the synthetic materials.1, collagen-dex-

tran bioscaffold; 2, Nano HA; 3, Si HA.

Figure 2. PA radiographs at 12 wks: A Autograft; B nanocrystalline hydroxyapatite

with a collagen-dextran bioscaffold; c Si HA.

Figure 3. Sagittal view of CTs at 12 weeks. A Autograft; B nanocrystalline hy-

droxyapatite with a collagen-dextran bioscaffold; C Si HA.

Figure 4. Histology (10x objective) in the center of the fusion at 12 weeks. A Au-

tograft; B nanocrystalline hydroxyapatite with a collagen-dextran bioscaffold; C Si

HA; ^ autograft, * new bone # fibrous tissue.

Figure 5. Tensile mechanical data.

CONCLUSIONS: The nanocrystalline HA with synthetic a collagen-dex-

tran bioscaffold resulted in a mechanically superior fusion compared to the

Si substituted graft and was equivalent to the gold standard in this model-

iliac crest autograft with BMA. There was no evidence of a foreign body or

inflammatory response to either test material.

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

any applicable devices or drugs.

doi: 10.1016/j.spinee.2009.08.165

137. AxiaLIF vs. ALIF as Supplemental Hardware in Long Posterior

Fusion Constructs

Justin Scheer1, Kathleen Koch1, William Mulkerin1, Thuc-Quyen Nguyen2,

Jovauna Currey3, Jenni Buckley, PhD1, Christopher Ames, MD1,

Robert McClellan, MD1, Shane Burch, MD1; 1University of California,

San Francisco, San Francisco, CA, USA; 2University of California, San

Francisco, Berkeley, CA, USA; 3University of California, San Francisco,

San Franciso, CA, USA

BACKGROUND CONTEXT: Current practice in fusing across the lum-

bosacral junction with a long posterior construct is by combining the pos-

terior instrumentation with fixation to the ilium, and/or performing a TLIF

or ALIF. While these approaches lessen the potential for screw loosening,

fracture, or non-union, they are associated with higher patient morbidity

due to prolonged exposure (TLIF) or staged surgery (ALIF). AxiaLIF

(TranS1) utilizes a novel percutaneous, presacral technique to access the

L5/S1 disc space. The AxiaLIF consisting of a single threaded screw,

can be inserted in the same operative setting as the original posterior

fixation.

PURPOSE: The purpose of this study was to compare AxiaLIF versus

ALIF as supplemental anterior fixation in long fusion constructs.

STUDY DESIGN/SETTING: Biomechanical testing on cadaveric lumbo-

pelvic specimens with four different fusion constructs: with and without

anterior fusion and with the posterior fusion terminating at the sacrum

and the ilium. Both ALIF (femoral ring allograft) and AxiaLIF anterior

constructs were tested. Repeat measures test design was employed.

PATIENT SAMPLE: Intact lumbosacral spines with attached pelvis

(N514, L1-S1) were harvested from fresh human cadavers (F58, M56;

61611 y.o.).

OUTCOME MEASURES: Range-of-motion (ROM) at L5/S1 during

flexion. Preliminary tests established that this measurement was well cor-

related with pull-out force on the L5 pedicle screws.

METHODS: Total spine DEXA-BMD T-scores were obtained. For each

specimen, L3-Sacrum was fused bilaterally using standard hardware

(6.35 mm SS rod, 6.5x40 mm pedicle screws). This fusion was later ex-

tended to the ilium via bilateral iliac screws (7.5x70 mm). Specimens were

randomly assigned to receive either AxiaLIF or ALIF (femoral ring allo-

graft) supplemental anterior fusion. For each surgical configuration,