PURPOSE: This study compared two groups of AIS patients treated uti-

lizing two different techniques to determine if the addition of DVR man-

uvers provides a better spatial correction of the apical vertebrae.

STUDY DESIGN/SETTING: This a retrospective study comparing two

different techniques of scoliosis correction utilizing all pedicle screw

constructs.

PATIENT SAMPLE: The sample consisted of AIS patients who under-

went all posterior pedicle screw fixation.

OUTCOME MEASURES: Pre- and postoperative AP and lateral XRs

and CT scans were reviewed. The apical vertical translation (AVT) was

measured from the AP XRs. The thoracic kyphosis was measured from

the lateral XRs. The total number of fixation points were also recorded.

The apical vertebral rotation was measured from CT scans. The patients

were matched according to age at surgery, curve location, COBB angle,

degree of flexibility, and fusion levels.

METHODS: 14 patients had surgery utilizing the rod translation maneu-

ver (group I). 13 patients had surgery utilizing the rod derotation, and DVR

applied simultaneously along with direct corrective force at the apex

(group II).

RESULTS: A significant improvement in the rotational and coronal planes

was found (p ! .05). In group I, mean rotation decreased from 15.7 to 12.7

degrees (19.5%) while in group II, from 18.1 to 12.7 degrees (30%). The

AVT improved from 33.4 to 17.5 mm (47.8%) in group I and from 41.0 to

15.7 mm (61.7%) in group II. Kyphosis remained relatively unchanged in

both groups: from 35 to 33 degrees (6%) in group I and from 30 to 27 de-

grees (10%) in group II. The difference between the 2 groups was signif-

icant with p!0.05. The average number of fixation points in group I was

18 (12-26) while in group II was 22.7 (12-30).

CONCLUSIONS: Scoliosis correction utilizing the DVR and rod derota-

tion yeilds a better 3 dimensional correction. The hypokyphosing effect

was not seen in this study. While correction in the axial plane is a result

of DVR, improvement in the AVT could be due to the surgical technique

since both groups were similar in terms of COBB angle and flexibility. Ad-

ditionally, increased number of fixation points could also account for this

improvement.

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

any applicable devices or drugs.

doi: 10.1016/j.spinee.2009.08.328

P70. Different Patterns of Pulmonary Dysfunction Between

Congenital Scoliosis and Idiopathic Scoliosis

Bang-Ping Qian, MD, Ai-Bing Huang, MD, Yong Qiu, MD; Nanjing,

Jiangsu Province, China

BACKGROUND CONTEXT: Although the curve locations of congenital

scoliosisCSand idiopathic scoliosis (IS) may be similar, different results

about the pulmonary dysfunction patterns in them still existed. There were

few studies to evaluate the difference of pulmonary dysfunction between

CS and IS in relation to the location of scoliosis.

PURPOSE: This study is to investigate the difference in pulmonary func-

tion parameters between CS and IS.

STUDY DESIGN/SETTING: A retrospective study.

PATIENT SAMPLE: This study consisted of 141 IS patients and 73 CS

patients, aged from 7 to 20 years. There were 53 males and 161 females.

OUTCOME MEASURES: The degree of curvature was measured by us-

ing the Cobb method. Preoperative pulmonary function texts (PFTs) were

evaluated in all patients. The parameters of pulmonary function

(VC%,FVC%,FEV1%,MMEF%,MVV%) were recorded.

METHODS: PFTs were evaluated in all patients. According to the loca-

tion of apical vertebra, 214 patients were classified into thoracic group,

nonthoracic scoliosis group. In the thoracic group, patients were divided

into three subgroups: Group A, Cobb angle!60� (63 IS patients and 14

CS patients); Group B, 60 �Cobb angle!90� (26 IS patients and 17 CS pa-

tients); and Group C, Cobb angle90� (12 IS patients and 24 CS patients).

The parameters of pulmonary function(VC%,FVC%,FEV1%,M-

MEF%,MVV%) were analyzed between IS and CS groups. And,

comparison of parameters of pulmonary function in the group of age

#10 years were carried out.

RESULTS: The CS patients had a significant reduce in the percentage of

predicted pulmonary volumes(VC%,FVC%,MVV%) as compared with

those of Cobb angle-matched IS, both in thoracic and nonthoracic groups.

And in the thoracic scoliosis of IS group, the decrease in FEV1% was not

as large as that in the Cobb angle-matched CS group (80.0% vs. 64.2%).

Furthermore, in patients with the age #10 years, the pulmonary function

of CS was also more deteriorated than that of IS, while the Cobb angle be-

tween the two groups was also matched.

CONCLUSIONS: Different patterns of pulmonary disfunction between

CS and IS were observed. The pulmonary disfunction pattern of IS is re-

strictive, however, that of CS may be mixed. Whether the location of sco-

liosis was thoracic or nonthoracic, the impairment of pulmonary function

was more severe in CS than IS. The difference of pulmonary function be-

tween CS and IS may be existed before puberty.

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

any applicable devices or drugs.

doi: 10.1016/j.spinee.2009.08.329

P71. Biomechanical Evaluation of a Novel Anterior Atlanto-Axial

Fixation Construct

Steven Chang, MD1, Ali Baaj, MD2, Phillip Reyes, BS1, Ali Yaqoobi, MD1,

Seok Kwang Choi, MD1, Volker Sonntag, MD1, Neil Crawford, PhD1;1Barrow Neurological Institute, Phoenix, AZ, USA; 2University of South

Florida, Tampa, FL, USA

BACKGROUND CONTEXT: Atlanto-axial fixation is a necessary treat-

ment modality in a variety of pathologies, including cervical trauma, de-

generative disease and neoplasm. Several posterior fixation techniques

are currently in practice, including fixation of the C1 lateral masses to

the C2 pars, pedicles or lamina. Simple interspinous wiring is also an op-

tion. Anterior atlanto-axial fixation may be associated with less risk to the

neurovascular structures in the upper cervical spine, particularly the verte-

bral arteries. Furthermore, anterior fixation obviates the need for a two-

staged (front-back) procedure after odontoidectomy.

Figure. Mean angular range of motion for all conditions studied. Error bars denote

standard deviation.

151SProceedings of the NASS 24th Annual Meeting / The Spine Journal 9 (2009) 1S-205S

PURPOSE: To evaluate the biomechanics of a novel anterior atlanto-axial

fixation construct.

STUDY DESIGN/SETTING: Biomechanical study using nondestructive

flexibility testing and paired testing conditions in a single group of

specimens.

PATIENT SAMPLE: Seven human cadaveric specimens (Oc-C3).

OUTCOME MEASURES: Angular ranges of motion in each plane.

METHODS: Specimens were tested 1) Normal, 2) After destabilization

(odontoidectomy and C1 anterior arch resection), and atlanto-axial fixation

via novel anterior plate construct, 3) After removing the anterior plate con-

struct and placing a posterior, C1 lateral mass, C2 pars screw/rod construct

with interspinous graft and wiring. A servohydraulic test frame applied

nonconstraining pure moments (1.5 Nm) via strings and pulleys while an-

gular motion was tracked optoelectronically.

RESULTS: Both the anterior and posterior constructs significantly re-

duced the mean ROM in each plane after destabilization (Figure 1). There

was no statistically significant difference in the restriction of ROM be-

tween the posterior rod construct and the anterior plate construct, with

the exception of lateral bending (p50.03, paired 2-tailed t-test).

CONCLUSIONS: Anterior atlanto-axial plate fixation is technically fea-

sible and may be a viable alternative to traditional posterior screw/rod

constructs.

FDA DEVICE/DRUG STATUS: Anterior Atlantoaxial Plate: Investiga-

tional/Not approved.

doi: 10.1016/j.spinee.2009.08.330

P72. Combination Cell-Morphogen Therapy for Treatment of

Degenerative Disc Disease

Nicholas Renaldo, MD1, Emily Putney, DO1, Pasquale Rassano, MS1,

Daniel Grande, PhD2; 1North Shore Long Island Jewish, New Hyde Park,

NY, USA; 2Manahssett, NY, USA

BACKGROUND CONTEXT: The intervertebral disc is made up of the

nucleus pulposus and annulus fibrosis. Once injured, this structure has

a limited repair capacity which is further compromised by ensuing inflam-

mation and instability. Current surgical treatments aim to relieve pain and

neurological disability by artificially restoring spine kinematics via fusion

or decompression.

PURPOSE: Our aim is to find a biological alternative to surgery that rec-

reates a healthy disc space and restoring spine kinematics resulting in im-

proved function and comfort. This study explores a combination therapy

for treating intervertebral disc disease using morphogens and mesenchy-

mal stem cells. We hypothesize that morphogens together with MSC’s de-

livered into the degenerative intervertebral disc space will result in an

improved biological repair in a model of degenerative disc disease.

STUDY DESIGN/SETTING: Rats were enrolled for creation of the de-

generative disc. The rats were anesthetized and a one inch incision was

made distal to the sacroiliac joint exposing three coccygeal disc spaces.

A scalpel was inserted 1.5 mm deep in order to iatrogenically injure the

disc spaces and create a reproducible degenerative disc model. The skin

was closed and pain medication was provided immediately post opera-

tively with unrestricted activity for 3 weeks and then randomized to treat-

ment groups which included: control, msc’s alone, growth factors alone,

combination of msc’s and growth factors.

PATIENT SAMPLE: 20 adult Sprague Dawley rats.

OUTCOME MEASURES: Basic science study. Outcome represented by

histologic analysis.

METHODS: After 3 week’s treatment the animals were sacrificed and the

disc spaces harvested. Analysis of the vertebral endplates, annulus fibrosis

and nucleus pulposus was performed under light microscopy at 4X, 10X,

and 100X.

RESULTS: Control: The nucleus pulposus was observed to be hypocellu-

lar or completely reabsorbed, with joint space collapse. GDF-5: Although

degenerative changes did exist in some of the discs, there was maintenance

of the nucleus pulposus shape and size with increased stellate cellularity

compared to untreated controls. BMP-2: The articular cartilage of both

end-plates demonstrated isogenic chondrocytic pools associated with in-

creased thickness of the parallel nucleus pulposus basement membrane

and hypercellular nucleus. GDF-5 & MSCs: Nucleus pulposus were often

shrunken with decreased cellularity in this group contributing to decreased

disc height, while the endplates and annular fibers maintained structural in-

tegrity. BMP-2 & MSCs: This group demonstrated increased disc height as

compared to the control group as well as increased cellularity of the nu-

cleus pulposus. Several discs demonstrated pools of small, isogenic, baso-

philic cells.

CONCLUSIONS: This study allowed us to examine the repair process in

a model of intervertebral disc degeneration. When grading the treatment

groups with respect to cellularity and disc height, order of worst to best

regeneration is as follows; controlOGDF-5OBMP-2OGDF-5 and MSCOBMP-2 and MSC. The use of BMP-2 alone or with MSC caused increased

chondrocytic growth and activity. It appears to have an additive effect with

MSC’s. The effect of GDF-5 alone was more consistent than the GDF-

5&MSC combination treatment, which did not act in an additive manner.

Future applications of morphogen therapy include the use of hydrogels and

scaffolds as delivery devices for maintaining disc tissue in vivo.

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

any applicable devices or drugs.

doi: 10.1016/j.spinee.2009.08.331

P73. Effect of Fusion Levels on Lumbosacral Fixation in Long

Fusion Construct

Rahul Chaudhari, MD1, Chunhui Wu, PhD2, Xiujun Zheng, MD1,

Amir Mehbod, MD1, Ensor Transfeldt, MD1; 1Twin Cities Spine Center,

Minneapolis, MN, USA; 2Foundation for the Advancement of Spinal

Knowledge, Minneapolis, MN, USA

BACKGROUND CONTEXT: Long fusion has high risks of peusoarthro-

sis at L5S1 and pullout failure of S1 screws. Many biomechanical studies

of long construct have been primarily focused on various fixation tech-

niques, such as multiple sacral screws, iliac screws, and anterior column

support, in protecting the S1 pedicle screw. No studies have evaluated

the effect of the number of fusion levels.

PURPOSE: The objective of this study is to determine how the number of

fusion levels affects the pullout force and bending moment applied to the

S1 screws.

STUDY DESIGN/SETTING: This is a biomechanical study on cadaveric

calf spines.

PATIENT SAMPLE: Six calf spines (T12-L6) were used for this study

(L6 is simulated as S1). Muscles were removed leaving the ligamentous

structures intact.

OUTCOME MEASURES: The bending moment and pullout force ap-

plied to the S1 screw was calculated from the strain gage signals.

METHODS: Fourteen pedicle screws were inserted. Strain gages were ap-

plied to the spinal rods located between L5-L6. Pure flexion moment

(7.5 Nm) was applied to the partially fused construct as the level of fusion

varied between 1-6 levels. The number of fusion levels increased from

lower vertebrae to upper vertebrae. For example, one level fusion was per-

formed at L56. Two level fusion was performed at L46, and so forth. One

way repeated measure ANOVA was used to analyze the pullout force and

bending moment data.

RESULTS: For single level fusion, the pullout force is negligible. There

was significant increase in the pullout force at the lowest screw in multi-

level fusion construct (p!0.05). However, there was no significant differ-

ence among fusion levels greater than two. Addition of interbody devices

reduced the pullout force (p!0.05). The detailed results of the pullout

force are shown in Figure 1. The bending moment also increased from sin-

gle level to multilevel fusion. There was no difference among fusion levels

greater than two. Addition of anterior cages significantly reduced bending

152S Proceedings of the NASS 24th Annual Meeting / The Spine Journal 9 (2009) 1S-205S