Proceedings of the NASS 19th Annual Meeting / The Spine Journal 4 (2004) 3S–119S 75S

Fig. 1

STUDY DESIGN/SETTING: Adult bovine nucleus pulposus (NP) cellswere transduced with adenoviruses expressing BMPs-2, -3, -4, -5, -7, -8,-10, -11, -12, -13, -14, and -15; the effects on proteoglycan accumulationswere determined.PATIENT SAMPLE: NAOUTCOME MEASURES: total proteoglycans.METHODS: Recombinant adenoviruses expressing human BMP-2, -3,-4, -5, -7, -8, -10, -11, -12, -13, -14, -15, and green fluorescent protein (GFP,as control) were constructed using the AdEasy system. 1 Intervertebral discwere isolated from young adult bovine tails. The NP cells were released withenzymatic digestion and then cultured in monolayer at high density.Adenovirus expressing BMPs (AdBMP) were included in the cultures atthe time of plating for 16 hours at an optimized multiplicity of infection.100 ng/ml of rhBMP-7 was included in the culture as a positive control.Cells were cultured at 370C with daily changes of medium (DMEM/F12:1/1) containing 20% FBS and ascorbic acid (25 mg/ml) for six days. Cellswere then digested with papain and the digests were analyzed for contents oftotal sulfated proteoglycans by the dimethylmethylene blue dye-bindingmethod. 2 The values for proteoglycan content reported represent the aver-age of the data obtained from the analysis of three separate cultures. P-values were obtained with the unpaired student t-test.RESULTS: AdBMP-2, -4, -5, -7, -8, -10 and -13 effectively stimulatedproteoglycan accumulation by bovine NP cells (p�0.05). AdBMP 7 wasas effective as the direct administration of rhBMP-7 (100 ng/ml) in terms ofstimulating proteoglycan accumulation (Figure).CONCLUSIONS: We have shown, for the first time, a direct comparisonof the effects of adenovirus expressing twelve BMPs on bovine NP cells.AdBMP7 was the most effective BMP studied in stimulating proteoglycanaccumulation, being very similar in magnitude to that observed for thedirect delivery of a dose of the recombinant protein. The gene therapyapproach, however, offers the advantage of promoting sustained proteo-glycan production. These findings provide guidance in the choice of BMPsand/or genes for treatment of IVD degeneration.DISCLOSURES: No disclosures.CONFLICT OF INTEREST: Authors (HA, FP) Grant Research Support:Stryker Biotech Inc.

doi: 10.1016/j.spinee.2004.05.148

P66. Neck pain following anterior cervical discectomy and fusionsignificance of interbody graft sizeBrian Kwon, MD1, Andrea Marvin2, Louis Jenis, MD1, David Kim,MD1; 1The Boston Spine Group, New England Baptist Hospital, Boston,MA, USA; 2University of Massachusetts, School of Medicine, Worcester,MA, USA

BACKGROUND CONTEXT: The ideal graft height used for anteriorcervical discectomy and fusion (ACDF) has not been well established.Too small a graft has been associated with loss of lordosis and abnormalbiomechanical loading of the cervical spine. Too large (“overstuffing”) agraft has been associated with graft absorption and nonunion. It has alsobeen suggested that placement of an overly tall graft may lead to excessiveloading of the posterior facet joints and may be a significant cause ofpostoperative neck pain.PURPOSE: This study was performed to determine whether there was aclinically significant relationship between changes in disc space distractionor angulation and clinical outcome with respect to neck or arm pain.STUDY DESIGN/SETTING: Prospective data collected and reviewed onpatients who underwent ACDF in a single institution.PATIENT SAMPLE: Patients who underwent ACDF in our institutionand had complete pre-operative and follow-up radiographs.

P21. Charite artificial disc replacement evaluation of the learningcurve and complications in a multicenter prospective randomizedcontrolled FDA IDE trialJohn Regan, MD1, Paul C. McAfee, MD2, Richard Guyer, MD3, ScottBlumenthal, MD4, Fred Geisler, MD5; 1Cedars-Sinai Medical Center,Los Angeles, CA, USA; 2Spine and Scoliosis Center, Towson, MD, USA;3Plano, TX, USA; 4Texas Back Institute, Plano, TX, USA; 5ChicagoInstitute of Neurosurgery and Neuroresearch, Chicago, IL, USA

BACKGROUND CONTEXT: European and U.S. studies have reportedsuccess with the Charite Artificial Disc(CAD).PURPOSE: We compared the results and complications of the first prospec-tive multicenter randomized controlled trial with respect to initial caseexperience and case volume per site.STUDY DESIGN/SETTING: 375 patients were enrolled in 15 centersunder an FDA approved protocol after obtaining IRB approval and informedconsent. Criteria for patient selection included age 18–60, single level

symptomatic degenerative disc disease at L4–5 or L5-S1 proven using MRIand discography and failure of 6 months conservative therapy. Patientswith osteoporosis, previous fusion, multiple level disease and medical healthco-morbidities were excluded.PATIENT SAMPLE: Data was collected on 276 patients (71 trainingand 205 randomized) who received the CAD and 99 BAK patients. Operatedlevels for CAD were 144 at L5-S1 (70%) and 61 at L4–5(30%). Minimumfollow up was 2 years in 91% of patients.OUTCOME MEASURES: Initial five training cases per site, total 71,were compared to 205 randomized cases with respect to hospital stay,surgery time, blood loss, change in VAS and Oswestry and number andseverity of complications at intervals up to 2 years.METHODS: High volume sites that enrolled greater than 15 patients (total120) were compared to sites with less than 15 cases (total 85) to determineif the case load effected those same parameters.RESULTS: Mean surgery time was significantly improved in the random-ized group (110.8min) compared to the training group (141.9min) (p�.001).VAS and Oswestry scores had greater improvement in the initial trainingcases compared to the randomized cases. There was a higher rate of compli-cations in the initial group compared to the remaining cases (p�0.0123).No differences were noted with respect to hospital stay and blood loss.With regard to major complications (vessel injury, neurological damage,nerve root injury, or death) the overall incidence was 1%. Device failurerequiring revision or removal was 7% for the training and 4% for therandomized cases. Patients in the high enrolling group had a meanhospitalization of 3.5 days compared to 4.5 for the training cases (p�.0114).Operative time was less for the high enrolling sites compared to the siteswith less than 15 cases (p�.0001). Absolute change in VAS and Oswestryscores was similar in both groups. Major complications of device failureand neurological deterioration occurred more frequently in the low volumegroup.CONCLUSIONS: There is a learning curve associated with operative timeand major complications which improves after five cases. Outcomes were noteffected by experience and were high in all groups evaluated indicatingthe high success rate of the procedure regardless of initial or overall experi-ence. Differences in sites compared on the basis of volume show shorteroperating time, hospitalization and a lower number of complications inhigh volume centers.DISCLOSURES: Device or drug: Charite Artificial Disc. Status: Investiga-tional/Not approved.CONFLICT OF INTEREST: Author (JR) Consultant: consultant DePuyJ&J.

doi: 10.1016/j.spinee.2004.05.149