Proceedings of the NASS 20th Annual Meeting / The Spine Journal 5 (2005) 1S–189S 165S

RESULTS: Results reveal that TDR is able to restore and preserve motionat all time points (approximately 9 degrees at �12 months). The results alsoreveal that more motion is gained when the postoperative disc is within0.8–2 times the preoperative disc height, versus 2–4 times (9–10 versus5–6 deg, p�.05). Comparing to the unaffected adjacent disc, again moremotion was seen when the postoperative disc height was within 0.8–2 timesthe “normal” disc. Specifically, discs likely to be distracted most (relativeto preoperative) were those most collapsed–these showed the least postoper-ative motion, were difficult to distract intraoperatively, and were morelikely to be at L5-S1. VAS and ODI significantly decreased in all TDRpatients, although less improvement occurred with the most distracteddiscs (p�0.05).CONCLUSIONS: Disc mobility and clinical outcome may be optimizedby achieving disc heights close to those of the unaffected adjacent discs.However, less postoperative motion can be expected after TDR at a highlycollapsed disc. This tends to be more common at L5-S1, where there may beless motion to begin with. Moreover, the tensioning of tissues around ahighly collapsed disc after TDR may contribute to reduce range of motionas well.DISCLOSURES: FDA device/drug: ProDisc-II prosthetic disc. Status:Investigational/not approved.CONFLICT OF INTEREST: No conflicts.

doi: 10.1016/j.spinee.2005.05.326

P112. Early experience with a minimally invasive vertebralreconstruction technique utilizing contained bone graftKarl Schultz, Jr., MD, Todd Stewart, MD, Gilbert Chandler, MD,Nabil Muhanna, MD; Specialty Clinics of Georgia, Gainesville,GA, USA

BACKGROUND CONTEXT: The growng successful use of verte-broplasty and kyphoplasty with methylmethacrylate (MM) to treat painfulosteoporotic, traumatic, and neoplastic compression fractures is well docu-mented. However, embolism, risk of extravasation, and adjacent segmentfractures remain realistic concerns with MM. A contained biologic alterna-tive to MM would have the theoretical advantages of being non-toxic,osteoconductive, and more closely approximate the modulus of elasticityof native bone, possibly reducing the incidence of subsequent adjacentsegment fractures.PURPOSE: To evaluate the feasibility and efficacy of a novel minimallyinvasive biological vertebral reconstruction technique in the treatment oftraumatic, osteoporotic, and neoplastic spinal compression fractures. Spe-cific attention is paid to clinical outcome and complications (includingincidence of adjacent segment fractures).STUDY DESIGN/SETTING: Prospective clinical feasibility and efficacyevaluation in a multispecialty clinic treating traumatic, osteoporotic andneoplastic vertebral body fractures.PATIENT SAMPLE: 50 vertebral levels treated in our first 40 patients. Agerange�37–96 follow-up�3–12 months Traumatic compression fractures:n�6 Osteoportic compression fractures: n�41 Neoplastic compressionfractures: n�3.OUTCOME MEASURES: Visual Analog Pain Score (pre and post proce-dure); Immediate CT scan after procedure CT scan and Xrays at 6 monthspost procedure.METHODS: Prospective evaluation of patient’s VA pain score, Xrays,and CT scan by independent observer. Preop X-rays, Postop X-rays, PostopCT scan, and 6 month postop CT scan and X-rays evaluated and scoredon percentage of collapse. Preop bone density scores recorded when appro-priate. Pain score and stability of vertebral reconstruction (ie, collapse,migration, infection, etc) each recorded at follow-up time points.RESULTS: A significant improvement in pain scores (VAS) was seen inall but two patients at their latest follow-up. All but two fractures (4%)were stabilized by the procedure at latest follow-up. There was one case(2%) of adjacent segment fracture during the follow-up period. Whilethere was no evidence of implant containment failure, there were two cases

of encroachment of the implant into the spinal canal, both related to operatorerror. There were two infections in two separate patients, 1) a superficialtract infection, and 2) a postoperative osteomyelitis.CONCLUSIONS: In our early experience, the expandable allograft implantappears to be an effective and safe treatment alternative to MM for themanagement of spinal compression fractures. With the rates of adjacentsegment fractures only 2% in our early study, the improved modulus ofelasticity of this technique may reduce adjacent segement fractures, a com-plication currently being seen more frequently with the use of non biologicssuch as methylmethacrylate.DISCLOSURES: FDA device/drug: Optimesh. Status: Approved forthis indication.CONFLICT OF INTEREST: Author (KS) Consultant: Spineology.

doi: 10.1016/j.spinee.2005.05.327

P113. Outcome evaluation of operative and nonoperativemanagement of lumbar disc protrusion causing radiculopathyKenneth Thomas, MD1, Charles Fisher, MD2*, Paul Bishop, MD3,Michael Boyd, MD2, Peter Wing, MB2, Marcel Dvorak, MD2;1University of Calgary, Calgary, Alberta, Canada; 2University of BritishColumbia, Vancouver, British Columbia, Canada; 3Vancouver Gen.Hospital, Vancouver, British Columbia, Canada

BACKGROUND CONTEXT: Several authors have documented the fa-vorable natural history of lumbar disc protrusion causing radiculopathy andits predictable response to nonoperative care. On the other hand, clinicalimprovement may be greatly accelerated by lumbar microdiscectomyand it is for this reason that lumbar discectomy is among the most commonsurgical procedures performed in North America. Studies using standardizedoutcome measures that compare nonoperative with operative care are rareand clear treatment guidelines have not yet been identified.PURPOSE: To assess health related quality of life (HRQOL) followingeither lumbar discectomy or nonoperative care for lumbar disc protrusioncausing radiculopathy (LDPR).STUDY DESIGN/SETTING: Prospective cohort study from a tertiarycare referral center.PATIENT SAMPLE: Six-hundred and twenty-three patients, assessed forLDPR, were enrolled in a prospective cohort study. Four hundred ninetyseven patients, 333 in the lumbar discectomy group and 164 in the nonopera-tive group, had sufficient follow-up and were analyzed.OUTCOME MEASURES: Primary–NASS Lumbar Spine Instrument NSSScore Secondary–NASS Lumbar Spine Instrument PDS Score Short Form36 (SF-36).METHODS: Patients completed baseline as well as six and twelve monthgeneric (SF-36) and disease-specific (NASS Lumbar Spine Instrument)HRQOL measures. Demographic comparisons between groups, using stan-dard descriptive statistics, were made. Multivariable analysis was used toadjust for known confounders to obtain an unbiased regression coefficientfor the primary outcome–the neurogenic symptoms score (NSS) from theNASS instrument. Outcome measures were compared between groups andto published normative data.RESULTS: The NSS showed significant improvement in both the lumbardiscectomy and nonoperative care groups at the primary study end-point.The difference in the magnitude of improvement, between groups, wasnot statistically or clinically significant. The study was adequately powered.Of the secondary outcome measures only the NASS pain and disability score(PDS), mental health (MH) domain of the SF-36 and the mental componentsummary (MCS) of the SF-36 showed a significant difference between groupsfavoring surgery, the clinical significance of which is questionable..CONCLUSIONS: Health related quality of life after LDPR, as measuredin this study by NASS NSS was not meaningfully associated with thetreatment received, within the time frame of this study. At follow-up alloutcome measures remained lower than population normative scores, sug-gesting that irrespective of treatment an element of disability remained.DISCLOSURES: No disclosures.

Proceedings of the NASS 20th Annual Meeting / The Spine Journal 5 (2005) 1S–189S166S

STUDY DESIGN/SETTING: Retrospective review of 79 patients withmultilevel DDD/IDD causing disabling low back pain for at least 12 monthsbefore receiving two level TDR with the Charite artificial disc prosthesis.

CONFLICT OF INTEREST: No conflicts.

doi: 10.1016/j.spinee.2005.05.328

P114. Efficacy of delayed magnesium administration on spinal cordinjury in the ratAlex Mohit, MD, PhD1, Jiejang Zhou, MD2, Diana Wiseman, MD2,Andrew Dailey, MD3; 1University of Washington, Seattle, WA, USA;2University of Washington, WA, USA; 3University of Washington/Harborview Medical Center, Seattle, WA, USA

BACKGROUND CONTEXT: High dose methylprednisolone is com-monly administered in the setting of non-penetrating spinal cord injury.However, questionable clinical gains from its administration along with itsknown side effects have led to concerns regarding its routine use. Magne-sium is a well known neuroprotective agent in experimental brain injuryand spinal cord ischemia. It prevents glutamate toxicity by N-methyl-D-aspartate receptor blockage in neural structures.PURPOSE: To study the efficacy of intravenous magnesium sulfate inreduction of secondary injury after non-penetrating spinal cord injury in arat model.STUDY DESIGN/SETTING: Laboratory study in an animal model forspinal cord injury.PATIENT SAMPLE: None.OUTCOME MEASURES: BBB behavioral motor score.METHODS: Using the New York University (NYU) weight impactormodel for spinal cord injury, we produced lesions within spinal cords ofanesthetized Sprauge-Dwaley rats after thoracic laminectomy. The animalswere then observed using a behavioral motor scoring system (BBB). Theanimals were graded from 0 (no movement) to 21 (normal movement)weekly for a period of 4 weeks. Animals received either saline, methylpred-nisolone, magnesium alone or magnesium and methylprednisolone 10minutes after injury. After 4 weeks, we analyzed the sections of spinalcords from these animals by luxol fast blue for myelin and H&E.RESULTS: Comparison between animals that received magnesium andcontrol animals, revealed a 40% improvement in BBB scoring at 4 weeks.Histologic analysis revealed remarkable loss of myelin staining in controlanimals for up to 10mm form the impact site. The animals that receivedmagnesium had dramatically less myelin loss. Furthermore, administrationof magnesium up to 8 hours after injury produced the same BBB scoresas animals that received it 10 minutes after injury. Administration of magne-sium at 12 and 24 hours after injury produced similar BBB scores ascontrol animals.CONCLUSIONS: These results, although preliminary, suggest that intra-venous administration of magnesium has a protective effect against second-ary injury in the rat spinal cord. This is evidenced by improved clinicalperformance of these animals at 4 weeks and preservation of myelin onspinal cord sections.DISCLOSURES: FDA device/drug: Magnesium Sulfate. status: Not ap-proved for this indication.CONFLICT OF INTEREST: No conflicts.

doi: 10.1016/j.spinee.2005.05.329

P115. Two level lumbar disc replacement: retrospective study of 79patients with minimum follow-up period of one yearMatthew Scott-Young, MBBS, FRACS, FAORTHOA; Pacific PrivateClinic, Southport, Queensland, Australia

BACKGROUND CONTEXT: Surgical management of low back painsecondary to multilevel degenerative disc disease and internal disc disrup-tion (DDD/IDD) remains controversial. There is little published evidenceas to the success of two level total disc replacement (TDR).PURPOSE: To assess two level TDR as a treatment option for multilevelDDD/IDD, report the postoperative return to work rate, and assess theresults of compensation patients and patients with prior surgery.

PATIENT SAMPLE: A series of 79 patients since 1996 having had twolevel TDR performed by a single surgeon. One patient declined study entry.The average follow-up was 29 months (12–72). In 69 cases L4–5/L5-S1 TDRwas preformed, in 8 cases L3–4/L4–5, and in 1 case L3–4/L5-S1. Sevenpatients received a fusion at an adjacent level.OUTCOME MEASURES: Back and leg VAS, Oswestry Disability Index(ODI), and Roland-Morris Disability Questionnaire (R-MD).METHODS: Outcome measures were collected preoperatively and postop-eratively at 3, 6, 12, and 24 months, and annually thereafter. All patientscompleted preoperative and end point outcome measures; some did notcomplete all of their postoperative outcome measures. Operative time, bloodloss, complications, and length of hospital stay were documented. Patientcompensation status and postoperative return to work was documented.RESULTS: When comparing preoperative and end point assessments therewas a 77.9% improvement in back VAS, an 85.7% improvement in legVAS, a 35 point (68.1%) improvement in ODI, and a 12.4 point (71.9%)improvement in R-MD. As some postoperative outcome measures werenot completed subgroups with complete data were analyzed. Fifty patientscompleted a 12 month assessment. There was a 79.7% improvement inback VAS, an 89.7% in leg VAS, a 36.0 point (70.4%) improvement in ODI,and an 11.8 point (74.7%) improvement in R-MD. Thirty-four patientscompleted the 24 month data. There was an 80.6% improvement in backVAS, a 91.6% in leg VAS, a 43.1 point (78.0%) improvement in ODI,and a 13.6 point (77.5%) improvment in R-MD. Nine patients had priorsurgery. When compared with those with no prior surgery, no statisticaldifference was detected. There was a trend to suggest that the ODI andback VAS scores of the patients with previous surgery improved morequickly in the early stages. Fourteen patients were involved in compensationclaims at the time of surgery. Their results were compared with thosepatients without compensation claims. The numbers were too small tobe statistically significant, but there was a trend suggesting recovery wasdelayed in the compensation group. However, at 24 months there was nodifference in the outcome scores. In the patient sample, 87% of patientsreturned to work. The average hospital stay was 5.4 days. The averageoperative time was 85 minutes. The average blood loss was 130mls. Nomajor intra-operative complications were documented. One neurologicalcomplication was documented. Two revision procedures were preformed.No prosthetic failure occurred.CONCLUSIONS: Two level TDR in the lumbar spine for treatment ofmultilevel DDD/IDD is a viable option and will become part of the arma-mentarium of spine surgeons and possibly the treatment of choice. Thepostoperative improvements in outcome measures are significant and sus-tained. Prior surgery and compensation does not preclude a good result.DISCLOSURES: FDA device/drug: Charite disc prosthesis. Status: Notapproved for this indication.CONFLICT OF INTEREST: Author (MS) Consultant: DePuy Spine.;Author (MS) Other: Participates on DePuy Spine’s disc developement team.

doi: 10.1016/j.spinee.2005.05.330

P116. Adipose stem cells can be induced towards the nucleuspulposus phenotypeMarco N. Helder1, Behrouz Zandieh Doulabi, PhD2,Roel J.W. Hoogendoorn, MD1, John K. Fraser, PhD3,Paul I.J.M. Wuisman, MD, PhD1; 1VU University Medical Center,Amsterdam, Netherlands; 2Academic Center of Dentistry–VrijeUniversiteit, Amsterdam, Netherlands; 3MacroPore Biosurgery Inc.,San Diego, CA, USA

BACKGROUND CONTEXT: Treatment of degenerative disc disease(DDD) with multipotent adult cells has the potential for regeneration ofthe nucleus pulposus (NP). Human adipose contains stem cell-like cells(ASC), however, it is not known if ASC can differentiate towards the NPcell phenotype.