Proceedings of the NASS 20th Annual Meeting / The Spine Journal 5 (2005) 1S–189S 131S

cage approach allows for a minimally invasive technique with few complica-tions and excellent outcomes.DISCLOSURES: FDA device/drug: Infuse. Status: Approved for this indi-cation. FDA device/drug: LT Cage. Status: Approved for this indication.CONFLICT OF INTEREST: Author (TK) Consultant: MedtronicSofamor Danek.

doi: 10.1016/j.spinee.2005.05.259

P45. Treatment of juxtafusional degeneration with artificial discreplacement (ADR): 2-year results of a prospective studyWon Joong Kim, MD, PhD, Soo Taek Lim, MD, Sang-Ho Lee, MD,PhD; Wooridul Spine Hospital, Seoul, South Korea

BACKGROUND CONTEXT: Artificial disc replacement (ADR), en-abling a mobile stability of a spinal segment, may be employed not onlyto prevent but also to treat the juxtafusional degeneration.PURPOSE: To determine the efficacy of ADR for treatment of symptom-atic juxtafusional degeneration.STUDY DESIGN/SETTING: Prospective clinical study.PATIENT SAMPLE: Ten consecutive patients with 2 years follow-upafter ADR were analyzed. The indications of ADR were symptomaticjuxtafusional degeneration with neurologicalcompromise and/or severe backpain unremitting to conservative treatment. Exclusion criteria were severefacet joint degeneration, posterior element defect, significant spinal mis-alignment, infection, fractured vertebral body, and negative provocativediscography.OUTCOME MEASURES: The clinical and radiological results of 10consecutive patients were evaluated at 2 years using Oswestry DisabilityIndex (ODI), Visual Analogue Scale (VAS) for leg and back pain, andstandard radiological methods.METHODS: The patients were subjected to anterior decompression ofthe neural elements followed by stabilization with ADR. In 2 patients,pseudarthrosis repair was performed with ADR.RESULTS: There were 4 males and 6 females with an age of 53.4 yearsat the time of operation. The junctional revision with ADR was mean5.5 years after their initial fusion surgeries. Presenting symptoms wereradiculopathy in 6, neurogenic claudication in 8 and significant back painin all the patients. The revisions were proximal to the fusion in 5 and distalto the fusion in 5 patients. There were no neurological or implant-relatedcomplications. At 2 years, radiculopathy and claudication were improved inall but 1 patient, who developed a repeat junctional degeneration on theopposite side of the fusion mass. Oswestry Disability Index (ODI) scoredecreased from 68 to 22.7 (67%). Visual Analogue Scale (VAS) score forback pain decreased from 8.3 to 3.2 (61%). VAS score for leg pain decreasedfrom 7.5 to 1.8 (75%). The replaced discs were all mobile with a meanrange of motion of 11.6 degrees. However, 3 patients developed repeatjunctional degeneration on the other side of the fusion opposite the ADR.CONCLUSIONS: Our results imply that ADR may be a reliable, minimallyinvasive alternative to an extension of fusion for treatment of juxtafusionaldegeneration in well-selected patients. However, ADR does not seem toprevent progression of degeneration on the opposite side of the fusion mass.DISCLOSURES: No disclosures.CONFLICT OF INTEREST: No conflicts.

doi: 10.1016/j.spinee.2005.05.260

P46. Fusion of the cervical spine using an anterior plate andhydroxyapatite graftFutoshi Suetsuna, Atsushi Ono, Tomoyuki Irie; Hachinohe MunicipalHospital, Hachinohe, Aomori, Japan

BACKGROUND CONTEXT: Problems related to anterior cervical fusion(ACF) using autogenous bone, including loss of cervical lordosis and graftsubsidence, have yet to be solved. Anterior plating has been used to help

minimize these problems. The use of a hydroxyapatite (HA) may providean excellent alternative to an autogenous bone.PURPOSE: To determine the efficacy and potential problems associatedwith ACF using an anterior plate and HA.STUDY DESIGN/SETTING: A retrospective study of patients treatedwith ACF using an anterior plate and HA.PATIENT SAMPLE: There were 48 men and 20 women with an averageage of 55 years. Preoperative diagnosis included 37 patients with myelopa-thy (Group 1) and 31 patients with spinal injury (Group 2). Patients wereevaluated both clinically and radiographically with a minimum follow-upof 2 yearsOUTCOME MEASURES: Clinical parameters included recovery rateusing JOA score in Group 1, Frankel criteria in Group 2, and complicationrates in both groups. Radiographic parameters included fusion rate, subsi-dence or crack of the HA, change in the lordotic angle of the fused segment,screw angle of insertion into the vertebral body, presence of lucency aroundthe screws, plate position, and failure or displacement of the plate.METHODS: We retrospectively reviewed the radiographic and clinicaloutcomes of 68 patients who underwent ACF with an HA with an averagefollow-up of 4.8 years (range 2–10 years). The degree of fusion wasclassified into four grades ranging from grade 1 (nonunion) to grade 4(complete union). The angle of screw insertion was divided into 3 types (type1:�10 degrees, type 2: 5–9 degrees, and type 3: 0–4 degrees). Lucencyaround the screws was evaluated using CT and plain radiographs. The HAused had a porosity of 40%.RESULTS: The fusion rate was 100% with all cases showing grade 4union without crack of HA. Group 1 average pre- and postoperative JOAscores were 11.2 points and 14.9 points. Recovery rate was 63.8%. 65.6%of Group 2 showed improvement of one or more grades using Frankelcriteria. There were no infections, esophageal injuries, or patients withevidence of neurologic deterioration. The angle of insertion of the screwswas type 1 in 92.6%, type 2 in 2.9% and type 3 in 4.4%. Of the threecases with type 3, two cases showed subsidence of the HA and one caseshowed breakage of the screw. Displacement of the plate was seen inone three-level fusion case. This displacement was likely caused byinsufficient bending of the plate. In four cases, the plate was noted toextend 1mm or more beyond the end plate of the vertebral body includedin the fusion. Two of these cases had spur formation. Lucency wasnoted around screws in two cases. Subsidence rate of the HA was 16.2%with an average of 1.5 mm. A decrease in lordotic angle of the fusedsegment was observed in three Group 2 cases with an average of 1.0 degree.The subsidence rate and decrease in lordotic angle of the fused segmentwere statistically less than that of our previously reported cases of ACFwithout anterior plating.CONCLUSIONS: This method of ACF using an anterior plate with anHA with proper screw insertion, correct plate positioning, and adequatecontouring of the plate produces excellent outcomes and fewer complica-tions than autogenous bone grafting techniques. We conclude that thistechnique can replace the use of autogenous bone for ACF for cervicalspondylosis and spinal injury.DISCLOSURES: FDA device/drug: hydroxyapatite. Status: Investiga-tional/not approved.CONFLICT OF INTEREST: No conflicts.

doi: 10.1016/j.spinee.2005.05.261

P47. Minimally invasive XLIF fusion in the treatment ofsymptomatic degenerative lumbar scoliosisRoberto Diaz, MD 1, Frank Phillips, MD2, Luiz Pimenta, MD, PhD 1*;1Santa Rita Hospital, Sao Paulo, Sao Paulo, NA, Brazil; 2RushUniversity Medical Center, Chicago, IL, USA

BACKGROUND CONTEXT: Surgical treatment of degenerative scolio-sis in the elderly typically involves large, morbid reconstructive surgeriesthat are often poorly tolerated. The authors have developed a minimallyinvasive eXtreme Lateral Interbody Fusion (XLIF) approach, which they

Proceedings of the NASS 20th Annual Meeting / The Spine Journal 5 (2005) 1S–189S132S

PURPOSE: Surgical treatments for such patients and their outcome afterrevision surgery have not been previously described. This study prospec-tively evaluated functional outcome after revision surgery for failed PLIF.STUDY DESIGN/SETTING: Prospective Cohort Series.PATIENT SAMPLE: Nineteen patients were referred to the senior authorafter having undergone a PLIF with metallic cages. History, physical exam,and imaging studies were performed both preoperatively and postopera-tively. All patients were diagnosed with a pseudarthrosis based on clinicalfindings and/or imaging studies.OUTCOME MEASURES: Patient demographics, SF-36, and OswestryDisability Index(ODI) data were collected preoperatively and 2 years post-operatively.METHODS: See above.RESULTS: Preoperative and postoperative data were collected on eighteenof nineteen patients (95%). Mean clinical follow-up was 2.5 years(range2–3 years). All required large amounts of narcotics preoperatively. Allcomplained of continued, incapacitating low back pain�proximal leg painafter the PLIF. CT scans revealed obvious pseudarthrosis in ten patients.All patients underwent revision decompression/fusion with iliac crest graftand pedicle screw instrumentation. Severe perineural fibrosis was found inall patients. Seventeen patients(94%) were felt to be fused on postoperativeimaging. Nine patients were taking no or minimal narcotics. Althoughimprovement was noted in seven of eight SF-36 sub-categories, it wassignificant only in two (Physical Function and Role Emotional). Therewas no significant difference in ODI scores.CONCLUSIONS: A high rate of radiographic fusion was obtained afterrevision posterior fusion, but seemed to only correlate with improved Physi-cal Function and Role Emotional on the SF-36 measures. Pseudarthrosisshould be considered if severe symptoms persist after attempted standalone PLIF procedures. Revision posterior fusion surgery may help insome respects, but good clinical outcomes are difficult to achieve in thesechallenging patients.DISCLOSURES: No disclosures.CONFLICT OF INTEREST: No conflicts.

doi: 10.1016/j.spinee.2005.05.263

P49. Restoration of segmental kinematics following nucleusreplacement with an in situ curable balloon contained polymerNathaniel Ordway, MS, PE1*, Anthony Tsantrizos, MSC, PhD2,Hansen Yuan, MD1, Bruce Bowman, SCD2; 1State University ofNew York Health Science Center at Syracuse, Syracuse, NY, USA;2Disc Dynamics, Inc., Eden Prairie, MN, USA

BACKGROUND CONTEXT: Discectomy is a common surgical proce-dure aimed at relieving pain stemming from herniated or degenerated lumbarintervertebral discs. Associated disc height and annular pre-tension lossesdue to discectomy impose altered segmental kinematics. These changes maylead to segmental instability, which may not only accelerate the degenerativeprocess and recurrence of pain, but may promote degeneration of adjacentlevels as well. Ultimately, surgical treatment of such conditions often leadto fusion. The goal of nuclear replacement technologies is to restore physio-

have applied in the treatment of degenerative scoliosis. The XLIF is accom-plished through two 1–2 inch incisions and incorporates a posterolateralblunt finger dissection of the retroperitoneal space, finger-guidance of aninitial dilator to the surface of the psoas muscle, EMG-guidance of thedilator through the psoas, and expansion of a split-blade retractor systemthat provides a working channel and direct visualization of the lateral disc.Standard intradiscal instruments are used for disc space preparation andimplant insertion.PURPOSE: Assess the safety and effectiveness of XLIF in the treatmentof degenerative lumbar scoliosis.STUDY DESIGN/SETTING: Prospective study.PATIENT SAMPLE: 18 patients with degenerative scoliosis with neuro-genic claudication and back pain were treated with XLIF procedure.OUTCOME MEASURES: Pain visual analog score (VAS) and Oswestrydisability index (ODI) were measured preoperatively and at various timepoints postoperatively. Pre- and postoperative measures of scoliosis andlordosis were recorded.METHODS: 18 patients underwent XLIF for the treatment of symptomaticdegenerative scoliosis. In all cases a 45 mm PEEK interbody implant wasplaced from side to side across the disc space at the scoliotic levels. Duringdisc space preparation, the far-side annulus was disrupted to ensure symmet-ric disc space distraction and that the interbody device filled with iliaccrest autograft would sit on the peripheral apophysial ring. In 1 case supple-mental pedicle screws were applied. Patients were followed clinically andradiographically for at least 1 year postoperatively.RESULTS: 18 patients (16 female, 2 male) with symptomatic degenerativescoliosis and spinal stenosis were included. Mean patient age was 68 yrs(range: 58–80yrs.) XLIF was performed at 1 to 4 lumbar levels (mean 2levels) between L2 and S1. Mean operative time was 125 minutes and inall cases measured blood loss was less than 50cc. All patients were out ofbed, ambulating and advanced to regular diet on the day of surgery. Onepatient wasdischargedon the1stpostoperative dayand theremaining patientswere discharged home on the 2nd postoperative day. There were noprocedural complications. Mean pain VAS decreased from 8.6 preopera-tively to 5.0 at 1 month postoperatively, to 4.8 at 1 year (p�.01). ODIimproved from 49 preoperatively to 41 at 1 month postoperatively and was24 at 1 year after surgery (p�.01). Scoliosis was corrected from 18 degrees to8 degrees;, and lumbar lordosis was improved from a mean of 34 degreesto 41 degrees (p�.01). All fusion sites were radiographically healed.CONCLUSIONS: In the authors’ experience, the XLIF procedure for thetreatment of symptomatic degenerative lumbar scoliosis results in painrelief, improved physical function and good sagittal and coronal planedeformity correction. The XLIF procedure was accomplished with a hospi-talization of 2 days or less and the rapid postoperative pain relief andimproved function suggest this to be a less morbid procedure than traditionallarge reconstructive surgeries for this condition.DISCLOSURES: FDA device/drug: Interbody Implant. Status: Approvedfor this indication.CONFLICT OF INTEREST: Authors (FP, PL) Consultant: Nuvasive;Authors (FP, PL) Speaker’s Bureau Member: Nuvasive; Authors (FP, PL)Stockholder: Nuvasive; Author (PL) Grant Research Support: Nuvasive.

doi: 10.1016/j.spinee.2005.05.262

P48. Prospective SF36 outcomes for revision surgery after failedPLIFEzequiel Cassinelli, MD1, Corey Wallach, MD2, Molly Vogt3,Brett Hanscom4, James Kang, MD3; 1Case Western Reserve University,Cleveland, OH, USA; 2University of Pittsburgh*, Pittsburgh, PA, USA;3University of Pittsburgh, Pittsburgh, PA, USA; 4Dartmouth College,Lebanon, NH, USA

BACKGROUND CONTEXT: Posterior lumbar interbody fusion(PLIF)with metallic cages was a popular treatment for degenerative lumbar disor-ders. Complications such as pseudarthrosis and persistent pain syndromeshave made this procedure less popular.

logical motion at the pathological level and prevent adjacent segmentpathology while minimizing the annulotomy necessary for a total nucleusremoval and effective implantation. The DASCOR Disc ArthroplastySystem is a unique contained injectable nuclear replacement device. It isimplanted into the nucleus cavity by injecting a custom formulated polymerunder pressure into a cavity conforming balloon through a small annular in-cision. The polymer cures in situ in a matter of minutes to a firm butpliable implant.PURPOSE: To determine whether segmental kinematics of a lumbarmotion segment having undergone a nucleotomy, can be restored withimplantation of the DASCOR device to those experienced by an intactmotion segment.STUDY DESIGN/SETTING: Human cadaveric biomechanical study.PATIENT SAMPLE: NA.