Proceedings of the NASS 20th Annual Meeting / The Spine Journal 5 (2005) 1S–189S26S

However, there were no differences in the operative segment range ofmotion or neutral zone when comparing the two treatments. The currentstudy serves as a basic scientific basis for ongoing clinical investigationsinto the use and efficacy of PSIS material following total disc arthroplasty.DISCLOSURES: FDA device/drug: Porcine Small Intestine Submucosa

(PSIS). Status: Investigational/not approved.CONFLICT OF INTEREST: Author (BWC) Grant Research Support:DePuy Spine.

doi: 10.1016/j.spinee.2005.05.050

5:4949. Small intestinal submucosa for nucleus pulposus augmentation:a feasibility study in rabbitsAkihiro Okawa, MD1, Catherine Le Visage, PhD2, Leena Kadakia2,Henry Yang, MD3, Ann Sieber4, Kam Leong4, John Kostuik4,Hiromi Matsuzaki5; 1Nihon University Tokyo, Tokyo, Japan; 2JohnsHopkins University, MD, USA; 3MD, USA; 4Johns Hopkins University,Baltimore, MD, USA; 5Nihon University Surugadai Hospital, Chiyodaku,Tokyo, Japan

BACKGROUND CONTEXT: One alternative therapeutic approacheaiming to retard the degeneration process is to transplant a matrix-richtissue into the intervertebral disc. Porcine small intestinal submucosa (SIS),a biodegradable extracellular matrix scaffold, has shown promise in promot-ing tissue regeneration.PURPOSE: The purpose of this study was to determine if porcine SIS isa potential bioactive scaffold for rescuing degenerative disc cells and toevaluate the efficacy of applying SIS as a disc replacement.STUDY DESIGN/SETTING: Comparative In vivo study in rabbit models.PATIENT SAMPLE: N/A.OUTCOME MEASURES: N/A.METHODS: Porcine SIS membranes (~50 mg each, 200 µm thick) wereimplantated in 25 New Zealand rabbits (weight 4 kg). Nucleotomy wasperformed in two non-consecutive levels. SIS membrane was implantedin one disc whereas the other level was left empty. Lateral plain radiographsof the lumbar spine were obtained to measure disc height. MRI (1.5T and4.7 spectrometer) T2-weighted images were used for measuring the discwater content. Total RNA was isolated from rabbit discs and the PCR wascarried out with the following primers: collagen I and II, aggrecan, decorin,metalloproteinases MMP9 and 13, Fas. Rabbit GAPDH was used as thehousekeeping gene. Statistical analysis was performed with a Student ttest to compare with gene expression levels in normal discs; p�.05 wasconsidered significant.RESULTS: Animals showed no signs of pain or restrained mobility aftersurgery and were sacrificed after 2 months. Disc height of nucleotomysites was significantly reduced in comparison with controls (0.51�0.021vs. 0.89�0.030 mm, respectively). A similar reduction of disc height to0.47�0.018 mm was observed in the SIS-implanted site. H&E stainedsections revealed the formation of fibrocartilagenous tissue. Gene expres-sion profile was examined for both operated and control levels. A totalnumber of 18 discs were analyzed by RT-PCR conducted at the 2-monthtime point. Each group (normal, nucleotomy, and SIS) consisted of 3 to 4discs. Although the amount of extracted RNA in the nucleotomy groupswas significantly lower than in the other groups, it was sufficient enoughto perform the analysis without pooling the disc samples. The gene expres-sion level for all different primers was then normalized to the GAPDHexpression in each disc and is represented. Compared with normal discs,all operated levels presented an up-regulated expression of collagen typesI and II and metalloproteinases MMP9 and 13, even though only the SISimplanted discs demonstrated a significant difference for collagen type I,type II, and MMP 13. The discs that underwent nucleotomy showed asignificantly lower level of expression of both aggrecan and decorin ascompared with normal discs (37% and 27% of normal level of ex-pression, respectively).CONCLUSIONS: We investigated the fate of SIS implanted into a rabbitdegenerative disc. The biodegradability of SIS was confirmed as well as

the formation of fibrocartilagenous tissue observed in some discs. The SISimplanted discs also showed increased MMP9 and MMP13 production.Moreover, expression levels of aggrecan, decorin in SIS implanted discswere restored to those of a normal disc. The results confirm the SIS biologi-cal activy in restoring the initial gene expression profile of normal disc cellsand thus in enhancing the synthesis of a new matrix. We have shown thefeasibility of implanting SIS into the disc space in rabbits and confirmedthe acute biocompatibility of this scaffold for intervertebral disc regeneration.DISCLOSURES: No disclosures.CONFLICT OF INTEREST: No conflicts.

doi: 10.1016/j.spinee.2005.05.051

Wednesday, September 28, 20055:31–6:31 PM

SIPP 2: Deformity

5:3150. Intervertebral subluxation, lumbar lordosis, but not Cobb anglecorrelate with surgical rates in adult thoracolumbar and lumbarscoliosis: a multicenter analysisFrank Schwab, MD1, Jean-Pierre Farcy, MD1, Keith Bridwell, MD2,Sigurd Berven, MD3, Steven Glassman, MD4, William Horton, MD5,John Harrast6; 1Maimonides Medical Center, Brooklyn, NY, USA;2Washington University in St. Louis, Saint Louis, MO, USA; 3Universityof California, San Francisco, San Francisco, CA, USA; 4University ofLouisville, Louisville, KY, USA; 5Emory University, Atlanta, GA, USA;6Dataharbor, Chicago, IL, USA

BACKGROUND CONTEXT: While classification systems for scoliosisin the pediatric population are well established, this has not been the casefor scoliosis in the adult. Recent reports have established radiographiccriteria with significant correlation to clinical symptoms but the impact ontreatment has not been investigated.PURPOSE: The purpose of this study was to analyze radiographic parame-ters shown to correlate with disability, and study the surgical rates associatedwith these parameters in a population of adults with thoracolumbar and/orlumbar scoliosis.STUDY DESIGN/SETTING: This is a multicenter prospective studyincluding 870 consecutive patients. Treatment modality (surgery vs. nonop-erative) was analyzed and correlated with radiographic parameters.PATIENT SAMPLE: All patients were enrolled through an IRB approvedprotocol. All patients were adult (�18 years of age) and had radiographicdiagnosis of scoliosis.OUTCOME MEASURES: Oswestry Disability Index, Scoliosis ResearchSociety instrument 29 (SRS-22, SRS 24).METHODS: The 870 consecutive patients were drawn from the SpinalDeformity Study Group database of adult patients with scoliosis of thethoracolumbar and/or lumbar spine with an apex at any level from T11down to L4 (of degenerative or idiopathic origin). For all subjects, radio-graphic analysis (from full-length standing films) included: frontal planeCobb angle, apical level, sagittal plane lumbar alignment (T12-S1), frontaland sagittal plane intervertebral subluxations. Completed health assessmentquestionnaires were available for all subjects (Oswestry Disability Index,Scoliosis Research Society instrument [SRS-29]). The treatment approachfor each patient was tabulated (surgical vs. nonsurgical). Surgical rates wereanalyzed by grouping patients into categories, based upon radiographicparameters (statistical comparison [t test]).RESULTS: For the 870 patients, (average age 48 years, SD 18) the meanfrontal plane Cobb angle was 46 degrees (SD 20 degrees). Lumbar lordosis(T12-S1) was: for 505 patients �400, for 249 patients 0–40 degrees, for39 patients �0 degrees (kyphotic). Of the study group 388 patients hadfrontal or sagittal plane intervertebral subluxation (1–6 mm in 102 patients,�7 mm in 286 patients). Treatment reported was surgical in 42% ofpatients. Significant differences were noted in surgical rates and disability

Proceedings of the NASS 20th Annual Meeting / The Spine Journal 5 (2005) 1S–189S 27S

5:4352. Two-year single surgeon retrospective analysis of pediclesubtraction osteotomy: analysis of complication rateand percentage correctionEric Buchl, MPAS, PA-C1*, Alexis Shelokov, MD1, Jeff Garner, RNFA,CNOR2; 1Consulting Orthopedists, Plano, TX, USA; 2Plano, TX, USA

BACKGROUND CONTEXT: Pedicle subtraction osteotomy (PSO) andmultilevel Smith-Peterson osteotomy are the two most common surgicaloptions for fixed sagittal and coronal plane spinal deformity. Few large,single-surgeon series have been reported to date.PURPOSE: To report on operative complications and radiographic out-come of patients undergoing PSO.STUDY DESIGN/SETTING: Chart and radiographic review of a singlesurgeon’s patient, sequential cohort performed at one institution was carriedout to identify complications and percentage of deformity correction.PATIENT SAMPLE: All patients undergoing PSO for spinal deformityover the last 2 years were included in the study.OUTCOME MEASURES: Data represent complication rates and earlyradiographic follow-up on all patients. 0/78 patients have reached minimum

for patients with subluxation �7 mm compared with those with no subluxa-tion (surgical rate 37% vs. 52%, p�.001, ODI/SRS scores, p�.001), forpatients with lumbar lordosis exceeding 40 degrees compared with nolordosis (surgical rate 36% vs. 54%, p�.038, ODI/SRS scores p�.003).When patients were then grouped into a category of no subluxation andlordosis above 40 degrees compared with those with subluxation �7 mmand no lumbar lordosis (T12-S1, �0 degrees), significantly different surgi-cal rates were identified (34% vs. 61%, p�.02, ODI/SRS scores �0.002).CONCLUSIONS: This study is a unique multicenter analysis of thoraco-lumbar and lumbar scoliosis in adults. Previously established risk factorsfor greater “disability” (ODI, SRS-29) included loss of lumbar lordosis andintervertebral subluxation. This investigation has established that surgicalrates were also significantly influenced by these factors. The data in thisanalysis further support that a clinically significant classification approachto adult scoliosis can be established.DISCLOSURES: No disclosures.CONFLICT OF INTEREST: No conflicts.

doi: 10.1016/j.spinee.2005.05.052

5:3751. Concave thoracoplasty used in posterior correction of scoliosisYang Yu; Nanjing University, Spine Service, Gulou Hospital,Nanjing University Medical Sc, Nanjing, China

BACKGROUND CONTEXT: To investigate the methods and clinicalsignificance of elevation of concave thorax in posterior correction ofscoliosis.PURPOSE: To investigate the methods and clinical significance of eleva-tion of concave thorax in posterior correction of scoliosis.STUDY DESIGN/SETTING: To investigate the methods and clinicalsignificance of elevation of concave thorax in posterior correction ofscoliosis.PATIENT SAMPLE: All 20 cases were congenital scoliosis in our group,with the mean age of 15.5 years (10–21 years old). Nine cases had theelevation of concave thorax during the second-stage posterior correction,while 11 cases had single posterior correction and elevation of concavethorax. Three cases received both elevation of concave thorax and convexthoracoplasty (when the razor deformity was above 50 degrees).OUTCOME MEASURES: The mean number of rib osteotomy was 4.5.All 20 patients became satisfied (13 cases) and approximately satisfied (7cases) with their back shape. The mean razor deformity decreased from37.3 degrees to 10.9 degrees after surgery. The mean Cobb angle was 82degrees before operation and 37 degrees after pleural perforation and effu-sion occurred in 1 case, but recovered quickly after several aspirations.METHODS: The surgical technique was a modification of Mann’s. Thesecases were followed 15 months (from 6–36 months). The profile of defor-mity, Cobb angle, and X-rays were compared before and after surgery; thesurgical complication was recorded.RESULTS: The mean number of rib osteotomy was 4.5. All 20 patientsbecame satisfied (13 cases) and approximately satisfied (7 cases) withtheir back shape. The mean razor deformity decreased from 37.3 degrees to10.9 degrees after surgery. The mean Cobb angle was 82 degrees beforeoperation and 37 degrees after pleural perforation and effusion occurredin 1 case, but recovered quickly after several aspirations.CONCLUSIONS: Compared with the traditional convex thoracoplasty,the osteotomy of concave ribs increased the flexibility of the rigid spine,and was helpful to the posterior correction of the lateral curve. The surgeryalso elevated the depressed thorax in the coronal plane, and enlarged thevolume of the thorax. This technique was safe; most of the patients didnot need to receive another convex osteotomy.DISCLOSURES: No disclosures.CONFLICT OF INTEREST: No conflicts.

doi: 10.1016/j.spinee.2005.05.053

2-year follow-up. All patients have completed outcome questionnaire basedon SRS-22, Oswestry disability questionnaire, and visual analog scale;these will be analyzed at 2-year follow-up and reported subsequently.METHODS: Postoperative clinical course and the radiographic findingspre- and postoperatively for 78 patients undergoing consecutive PSO per-formed by one surgeon at one institution between 2002 and 2004 werestudied with 100% follow-up. The data represent early complication rateand radiographic results to date.RESULTS: The cohort included 64 (82.1%) females, 14 (17.9%) maleswith varying spinal deformity diagnoses. The mean age was 47.4 years atindex surgery. Mean OR time was 6.45 hours; mean blood loss was 2,063cc, mean pedicle screw number was 15.7 with mean X-ray exposure of358 seconds. Complication rate was divided into major and minor events.Major complications included: 9 hardware failures (11.53%), 5 pseudoar-throses (6.41%), 5 infections, both early and late (6.41%), 1 patient withpatchy right lower extremity paraparesis (2.56%). Minor complicationsincluded: 4 dural tears (5.13%), 2 cases of postoperative radiculopathy(2.56%), 2 patients with prominent hardware requiring removal (2.56%),1 case of drug-induced neurotoxicity (1.67%), 2 episodes of DVT (2.56%),2 cases of wound dehiscence (2.56%), 1 case of postoperative hepatitis(1.28%), 1 iliac crest bone graft infection (1.28%), 2 cases of internaljugular DVT (2.56%). The following percentage of correction was obtained:Primary cervicothoracic curve correction averaged 46.52% (Mean preopera-tive/postoperative curves were 47 and 25 degrees respectively). Primarythoracic scoliosis correction averaged 46.06% (Mean preop/postop curveswere 61 and 35 degrees respectively). For thoracolumbar curves, averagecorrection was 47.41% (Mean preoperative curve 61 degrees/ Mean post-operative curve 31 degrees). Primary lumbar curve correction averaged46.06% (Mean preoperative /postoperative curve 42 degrees 28 degreesrespectively). Primary kyphosis diagnosis, correction averaged 78.5% with97.5% improvement in C7 plumb line (within �2 cm of S1 landmark).CONCLUSIONS: PSO continues to be a powerful tool with which fixedsagittal andcoronal plane deformitiescanbe corrected. In this series, scoliosisand kyphosis deformities were corrected an average of 46.5 and 78.5degrees respectively. Despite this success, risks must be considered includ-ing blood loss, OR time, X-ray exposure, and a rate of complications of 29%.Thiscompares favorablywithpreviously reported incidenceofcomplicationsin adult scoliosis surgery. Continued investigation will be carried out toassess risk-to-benefit ratio of spinal osteotomies. This investigation is lim-ited because 2-year follow-up mark has not yet been met.DISCLOSURES: No disclosures.CONFLICT OF INTEREST: No conflicts.

doi: 10.1016/j.spinee.2005.05.054