71SProceedings of the NASS 22nd Annual Meeting / The Spine Journal 7 (2007) 1S–163S

reaction. Despite radiological signs of disc degeneration, the motion and

stability of the functional spinal unit was preserved. This is the first report

of a successful disc transplantation in the human and represents an innova-

tive new dimension in the management of degenerative spine disease in the

future.

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

any applicable devices or drugs.

doi: 10.1016/j.spinee.2007.07.174

148. Outcomes of Direct Pars Repair in Adolescent Athletes

Atiq Durrani1, Nadir Babekir2, Alvin Crawford, MD, FACS1; 1Cincinnati

Children’s Hospital Medical Center, Cincinnati, OH, USA; 2North

American Spine Society, Cincinnati, OH, USA

BACKGROUND CONTEXT: Management of symptomatic lumbar

spondylolysis/grade 1 Spondylolisthesis in adolescent athletes that doesn’t

respond to conservative treatment remains debatable. Direct Pars repair

(DPR) using pedicle screws and hooks has been reported in literature

but no report exists for the use of this technique in adolescent athletes

and its outcome regarding resolution of pain and return to sports in this

population.

PURPOSE: To report on 30 adolescent athletes who have been allowed to

return back to sports after 4 months following direct pars repair.

STUDY DESIGN/SETTING: Prospective cohort.

PATIENT SAMPLE: A cohort of adolescent athletes with spondylolysis

and/or grade I Spondylolisthesis who undergo Direct Pars Repair.

OUTCOME MEASURES: Post-operative outcome Time to return to

sport.

METHODS: 30 patients with lumbar spondylolysis/ grade 1 Spondylolis-

thesis who had failed extensive pre-operative rehabilitation and underwent

DPR using pedicle screws and hooks have been enrolled. Preoperatively,

all patients had radiographs, CT scan and MRI of lumbar spine. VAS score

for pain was collected pre and post-operatively. Patients began post oper-

ative rehabilitation at 2 weeks after surgery and returned to sports at 4

months.

RESULTS: 18 males and 12 females with a mean age of 14 years formed

the study group. 6 patients had L4 spondylolysis and 24 subjects had L5

spondylolysis. The mean pre-operative pain score was 8 while the 4 months

post-operative pain score was 1. Four months after DPR all patients

returned to sports. Post-operatively one patient failed to heal the pars break

and had to be converted to fusion for persistent pain at 1 year. However, no

intra-operative complications were noticed.

CONCLUSIONS: DPR is effective in resolving back pain due to lumbar

spondylolysis in adolescent athletes and allow them to return to sports

effectively.

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

any applicable devices or drugs.

doi: 10.1016/j.spinee.2007.07.175

149. Spinal Stenosis Decompression and Coflex� Interspinous

Stabilization: Clinical Results from an International Multicenter

Retrospective Study

Kornelis A. Poelstra, MD, PhD1, Dieter Adelt, MD2, Jacques Samani,

MD3, Woo-Kyung Kim, MD, PhD4, Marcus Eif, MD5, Gary L. Lowery, MD,

PhD6, Robert J. Chomiak, MS6; 1University of Maryland, College Park,

MD, USA; 2Ostseeklinik, Damp, Germany; 3Chururgie Orthpedique, Lyon,

France; 4Gachon Medical School, Gil Medical Center, Seoul, South Korea;5Klinik fuer Neurochirurgie Stadtisches Klinikum, Goerlitz, Germany;6Paradigm Spine, LLC, New York, NY, USA

BACKGROUND CONTEXT: Degenerative spinal stenosis is a severely

disabling disease common in the elderly with patient symptoms usually

including bilateral radicular pain that radiates to the buttocks and posterior

thighs, intermittent neurogenic claudication, sensation disturbance and

loss of strength in the lower extremities. The coflex� interspinous stabi-

lization device (Paradigm Spine) is a functionally dynamic implant (com-

pressible in extension) used to stabilize the motion segment after direct

surgical decompression of moderate to severe stenosis without concomi-

tant fusion. The coflex� is implanted after a direct surgical decompres-

sion of the stenotic canal and theoretically provides slight facet

distraction therefore off-loading the forces on the posterior degenerated

disc and facet joints at the affected level, while maintaining patency of

the neural foraminae.

PURPOSE: The purpose of this study was to determine the safety and

efficacy of coflex for the primary diagnosis of one or two level spinal ste-

nosis in patients with neurogenic claudication between the ages of 40 and

80 years old.

METHODS: Retrospective data were gathered on 589 patients from four

European sites and one Asian site where surgeons had contemporaneous

clinical and radiographic follow-up review of all patients. Follow-up was

available at 6 to 121 months for all patients. An analysis was performed

using VAS, objective examination measures, radiographic data and

Odom’s criteria to determine safety and efficacy of the coflex in relieving

neurogenic claudication, radiculopathy and back discomfort.

RESULTS: Of the 589 patients identified as recipients of a coflex im-

plant, a total of 429 were located and agreed to participate in the

study and contained a complete data set. The mean follow-up time

was 33 months and the median follow-up time was 20 months. Steno-

sis was the primary indication for 275 patients. Sixty-six patients did

not match our IDE inclusion criteria, which left 209 patients for anal-

ysis. Stenosis alone was the single diagnosis in 128 patients (61%), 57

patients (27%) had stenosis and a grade I spondylolisthesis and 24 pa-

tients (12 %) suffered from scoliosis (!25 degrees). Moderate to se-

vere low back pain improved in 75% of patients while leg pain

improved in up to 88% of patients. Claudication improved in 91%

of patients as well as 79 % improvement in walking distance. Using

Odom’s criteria, 88% of the patients scored good-excellent and 92%

said they would have surgery again. These results were achieved at

1 year and did not deteriorate over the long-term. No permanently

deformed or fractured coflex implants were seen. Two spinous process

fractures and 1 implant migration (O5 mm) were observed. Four pa-

tients underwent fusion after incomplete relief and explantation of

the coflex.

CONCLUSIONS: coflex interspinous stabilization after microsurgical

decompression for spinal stenosis demonstrates excellent short term

and long term results for back pain, neurogenic claudication and patient

satisfaction.

FDA DEVICE/DRUG STATUS: Coflex�: Investigational/ Not approved.

doi: 10.1016/j.spinee.2007.07.176

150. Biomechanical Evaluation of a Novel Anular Repair Device

Frank Phillips, MD1, Luiz Pimenta, MD, PhD2, David Spenciner, P.E.,

SC.M.3, David Paller, M.S.3, Ryan Rich3, Bret Ferree, MD4; 1Rush

University Medical Center, Chicago, IL, USA; 2Sao Paulo, Brazil; 3Brown

University, Providence, RI, USA; 4Cincinnati, OH, USA

BACKGROUND CONTEXT: Devices used to reconstruct the disrupted

anulus fibrosus (AF) after microdiscectomy or nucleus replacement (NR)

must be able to withstand pressure from intradiscal material so as to

prevent extrusion of the nuclear contents and must also permit spinal

movement. We performed biomechanical tests on a porous mesh-ePTFE

anular reconstruction device (Anova Corp, Summit NJ). The Anova device

is fastened to the spine with welded sutures and intra-osseous suture an-

chors to provide immediate stability.

PURPOSE: The goal of this study was to study the ability of the Anova

device to prevent nuclear extrusion after cyclical loading of the spine

72S Proceedings of the NASS 22nd Annual Meeting / The Spine Journal 7 (2007) 1S–163S

and also to test the ability of the device to withstand physiologic ranges of

motion of the tested spinal segments.

STUDY DESIGN/SETTING: Biomechanical.

PATIENT SAMPLE: Human Cadaver Spines.

OUTCOME MEASURES: Maximum pull-out force Extrusion of

intra-discal material with cyclic tests Maximum compression load.

METHODS: Pull-out testing: A strap was placed in the disc space of

six C5/C6 segments (FSUs). Fibular grafts were impacted into the disc

space anterior to the strap. Pull out testing was performed (5mm/min

for 20mm) after placement of the bone graft alone and then after insert-

ing the bone graft and applying the Anova device. Anova devices were

applied across posterior box anulotomies of 6 lumbar spine segments.

The spines were then placed through cyclic testing during which

a 2.5 Nm moment was applied sinusoidally for 30,000 cycles (15,000

flexion/extension, 10,000 lateral bending, and 5,000 axial rotation) after

which pull-out testing was performed. Motion Testing: 15 lumbar spine

segments underwent box anulotomies followed by insertion of 0.7cm3

of nucleus pulposus (NP) tissue (9 levels) or structural bone (6 levels)

into the discs. Anova devices were applied over the box anulotomies

followed by cycling of the spine as described. The range of motion

(ROM) of the spines was recorded. Compression testing: 8 lumbar FSUs

underwent box anulotomy followed by Anova device application. The

FSUs were loaded in axial compression until the transmitted load

reached a plateau.

RESULTS: Pull-out: The mean maximum pull-out forces after placement

of fibular grafts were 153.6N647.7N and 17.5N612.8N with and with-

out the Anova device respectively (p50.001). After 30,000 cycles, the

mean maximum pull-out resistance was 125.6N. Motion: No Anova de-

vice failed or intra-discal material (NP tissue or structural bone) extruded

after 30,000 cycles of the treated FSU. The Anova device permitted the

normal range of spinal motion. Static Compression: The average maxi-

mum compression load was 3143.961054.0N (2122-5598N) without An-

ova mesh tear, anchor extrusion, suture breakage, weld failure, or device

migration.

CONCLUSIONS: A porous mesh-ePTFE AF reconstruction device fas-

tened to the spine with welded sutures and suture anchors substantially

increases the force required to extrude intradiscal devices and intradiscal

material. In addition the Anova device did not fail under testing mim-

icking the loading and range of motion conditions of the normal spine.

These biomechanical data suggest a role for the Anova device as an

anular repair device that is able to contain nuclear material or devices

immediately after implantation as well as after cycling of the spine. The

porous mesh component that allows for incorporation of the Anova de-

vice into the anulus by fibrous ingrowth will provide for long-term

stability.

FDA DEVICE/DRUG STATUS: Anova Device: Investigational/ Not

approved.

doi: 10.1016/j.spinee.2007.07.177

151. An Independent Assessment of Long Term Outcomes Following

Decompression for Lumbar Synovial Cysts

Bradley Weiner, MD1; 1Houston, TX, USA

BACKGROUND CONTEXT: Outcomes of surgical intervention for lum-

bar synovial cysts have been evaluated in the short and intermediate term.

Concerns regarding cyst recurrence, the development of late instability at

the involved level, and instability/stenosis at adjacent levels (when con-

comitant) fusion is performed suggest that long term follow-up is needed

PURPOSE: This study aims to fill that void.

STUDY DESIGN/SETTING: Long-Term Follow-up Study.

PATIENT SAMPLE: Forty-six patients.

OUTCOME MEASURES: Outcomes were assessed using a customized

questionnaire evaluating: relief of pain/claudicant symptoms, numbness/

parasthesias, and weakness; as well as late onset low back pain, new

radicular symptoms, need for additional surgery, and patient satisfaction.

Outcomes in patients with or without fusion were compared as well.

METHODS: Forty-six patients operated by a single surgeon not involved

in the study were followed up long term at an average of 9.7 years (range

5 to 22 years) post-operatively. All patients underwent decompression

(þ/- concomitant arthrodesis in the presence of associated degenerative

spondylolisthesis) using the operative microscope for magnification/

illumination.

RESULTS: 87% of patients noted resolution of their pre-operative pain,

numbness, and weakness. 28% of patients developed late onset low

back pain. 17% developed late onset radicular symptoms in a new nerve

root distribution. 15% required subsequent additional surgery. 89% of

patients were satisfied with the surgical outcome. No differences were

found for any outcome measure between patients undergoing concomi-

tant fusion and those undergoing decompression alone using the two-

sample t-test.

CONCLUSIONS: This study provides outcome data at an average of

nearly ten years post-operative. This information should allow surgeons

to provide realistic expectations for their patients regarding outcomes

and should enhance the informed consent and surgical decision-making

process.

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

any applicable devices or drugs.

doi: 10.1016/j.spinee.2007.07.178

152. Minimally Invasive Microsurgical Lumbar Decompression with

Preservation of the Contralateral Outer Laminar Cortex and

Spinous Process: 4 Year Comparative Outcomes

Farbod Asgarzadie, MD1, Larry Khoo, MD2, Simona Bistazzoni3,

Marco Sassis3; 1University of California, Los Angeles, Santa Monica, CA,

USA; 2Los Angeles, CA, USA; 3Santa Monica, CA, USA

BACKGROUND CONTEXT: The technique of bilateral decompression

via a percutaneous unilateral minimally invasive decompressive laminoto-

mies (MIDL) with preservation of the outer laminar cortex and spinous

process has been previously described and early outcome assessments have

been published. However, there are no published data on long term

outcomes in this cohort of patients.

PURPOSE: Our objective is to assess long-term outcomes for patients

with lumbar spinal stenosis who underwent MIDL technique.

STUDY DESIGN/SETTING: A retrospective cohort study of consecutive

patients who underwent the MIDL procedure at UCLA.

PATIENT SAMPLE: 48 patients with lumbar spinal stenosis were treated

via MIDL. The mean age of teh cohort was 64.5 years with 58% men and

42% women.

OUTCOME MEASURES: Operative time, intraoperative blood loss,

hospital stay, VAS, patient satisfaction, ODI, SF-36.

METHODS: 48 patients with lumbar spinal stenosis were treated via

MIDL. Patients had baseline interviews, exams and follow-up question-

naires at 3, 6, and 12 months, then annually thereafter.

RESULTS: Of 48 patients with lumbar spinal stenosis initially enrolled,

4-year outcomes were available on 42 patients. There were 28 one-level

and 20 two-level cases with operative data averages of: 55 minutes/level;

25cc blood loss/level, 1.5 day stay. After 4 years, 88% of the treated pa-

tients reported that their predominant symptom, either leg or back pain,

was better. All patients reported an increase in walking endurance at 6

months that was maintained in 80% of patients at a mean of 38 mos. Sat-

isfaction of patients with their current state at 4 years was reported by 78%

of the patients. The incidence of post-treatment symptoms was as follows:

radiculopathy (5 of 32 patients who had symptoms), symptomatic central

stenosis (2 patients at previously treated levels; 2 at untreated levels); sym-

tomatic axial mechanical low back pain (3 patients). Of these, 2 patients

were treated at a new operative level and 1 was reoperated at the prior

level. None of the 28 patients without listehesis went on to develop