Proceedings of the NASS 20th Annual Meeting / The Spine Journal 5 (2005) 1S–189S100S

6:06193. Complications of lumbar artificial disc replacement vs. fusionresults from the randomized multicenter FDA IDE Study of theCharite Artificial DiscRichard T. Holt, MD1, Mohammed Majd, MD1, Jorge Isaza, MD2,Scott Blumenthal, MD3, Paul McAfee, MD4, Richard Guyer, MD3,Stephen Hochschuler, MD3, Fred Geisler, MD, PhD5, Rolando Garcia,Jr., MD, MPH6, John Regan, MD7; 1Spine Surgery, PSC, Louisville, KY,USA; 2Louisiana Orthopedic Institute, Baton Rouge, LA, USA; 3TexasBack Institute, Plano, TX, USA; 4Spine and Scoliosis Center, Towson,MD, USA; 5Ilinois Neuro-Spine Center, Aurora, IL, USA; 6OrthopedicCare & Sports Medicine Center, Aventura, FL, USA; 7Cedars-SinaiInstitute for Spinal Disorders, Los Angeles, CA, USA

BACKGROUND CONTEXT: Prior reports of lumbar total disc replace-ment (TDR) have described significant complications. The FDA IDE studyof the CHARITE Artificial Disc represents the first Level I data comparisonof TDR to fusion.PURPOSE: To report the complications experienced by patients enrolledin the IDE study of the CHARITE Artificial Disc.STUDY DESIGN/SETTING: A prospective, randomized, multi-center,FDA-regulated Investigational Device Exemption clinical trial.PATIENT SAMPLE: A total of 304 patients enrolled in the IDE studyof the CHARITE Artificial Disc.OUTCOME MEASURES: Complications were recorded on adverse eventcase report forms, reported to the study sponsor and verified throughstudy monitoring.METHODS: Patients were randomized in a 2:1 ratio with 205 patients inthe CHARITE group and 99 patients in the control group (ALIF with BAKcages). Inclusion criteria included confirmed single-level DDD from L4-S1, and failure of nonoperative treatment for at least 6 months. Clinicaland Radiographic data were collected pre- and peri-operatively, at 6 weeks,and at 3, 6, 12, and 24 months following surgery. Complications in bothgroups were recorded throughout the entire study. Complications werereported throughout the study.RESULTS: The overall reported complication rate was equivalent betweenthe two groups. Approach-related complications were slightly higher in theTDR group (9.3% vs. 8.1%). Neurological complications were slightlyhigher in the control group (17.2% vs. 16.1%). The incidence of superficialwound infection was higher in the TDR group (6.3% vs. 2.0%), butthere were no device-related or deep wound infections in either group. Theincidence of retrograde ejaculation was 1.5% in the TDR group and 3.0% inthe control group. Postoperative ileus presented in 0.5% of the TDR groupand 1.0% of the control group. Additional surgery at the operative levelwas performed in 5.4% of the TDR group and 8.1% of the control group.In the control group, the pseudarthrosis rate was 9.1%, and the rate ofreported bone graft site pain was 18.2%. There were no catastrophic TDRdevice failures, and no cases of osteolysis. There were 7 (3.4%) device-related complications in the TDR group with 2 requiring removal.CONCLUSIONS: The complication rate of TDR with the CHARITE Arti-ficial Disc is similar to that of ALIF in properly indicated patients. Training,experience, proper sizing and positioning of the prosthesis, and avoidanceof overdistraction of the disc space will minimize complications.DISCLOSURES: FDA device/drug: CHARITE Artificial Disc. Status:Approved for this indication. FDA device/drug: BAK Cage. Status: Ap-proved for this indication.CONFLICT OF INTEREST: Author (JG) Other: employee, DePuy Spine;Authors (RTH, MM, JI, SB, PM, RG, SH, FG, JR) Consultant: DePuySpine; Authors (RTH, SB, PM, RG, FG, JR) Speaker’s Bureau Member:DePuy Spine; Authors (RTH, MM, JI, SB, PM, RG, SH, FG, JR) GrantResearch Support: DePuy Spine.

doi: 10.1016/j.spinee.2005.05.196

6:18195. Spine surgery operative positioning affects risk factorsfor compartment syndrome: leg intramuscular pressure,blood pressure, and applied loadBryan Leek, Robert Scott Meyer, MD, John Wiemann, Adnan Cutuk,MD, Brandon Macias, Alan Hargens, PhD; University of California,San Diego, CA, USA

BACKGROUND CONTEXT: Acute compartment syndrome of the legis an underreported complication during spine surgery using the 90/90kneeling frame.

6:12194. Influence of spacer position on sagittal alignment ininstrumented transforaminal lumbar interbody fusion

Howard Goodman, MD, Frank Schwab, MD, Matas Petracchi,Reid Boyce, MD, Jean-Pierre Farcy, MD; Maimonides Medical Center,Brooklyn, NY, USA

BACKGROUND CONTEXT: A single-stage circumferential fusion viaa posterior approach can be performed via two techniques, a posteriorlumbar interbody fusion (PLIF) or a transforaminal lumbar interbody fusion(TLIF). TLIF is gaining popularity because minimal retraction on the nerveroots and dural sac is required to access the disc. To achieve sagittalbalance segmental lumbar lordosis has to be preserved or acquired. To ourknowledge there have been no published reports assessing the impact ofthe spacer position on sagittal alignment in TLIF procedures.PURPOSE: Having developed and validated a classification system fordescribing the final placement of the interbody graft, the next step was toexamine the clinical significance. Without any published reports of theimpact of spacer placement, this new classification system allows a system-atic way of analyzing spacer placement and outcome criteria. The purposeof this study was to evaluate radiologically a correlation between the spacerposition in the interbody space and the segmental lordosis.STUDY DESIGN/SETTING: 65 patients who underwent TLIF had preop-erative and postoperative X-rays classified according to the new system.It was felt that a good outcome of the procedure would be change inlordosis of the instrumented segment. For that reason, the preoperative andpostoperative radiographs were measured for change in lordosis and thenthis difference was compared with final graft placement.PATIENT SAMPLE: This study encompasses 65 patients with 77 levelsinstrumented. Most of the patients had indications including spondylolisth-esis, spondylolysis, and degeneration with instability.OUTCOME MEASURES: The outcome measures used are the new classifi-cation system and the immediate change in lordosis of the instrumented segment.METHODS: This is a retrospective review of 77 levels in 65 patients whounderwent a TLIF. There was 1 fused segment at L2–L3, 4 at L3–L4, 44at L4–L5 and 28 at L5–S1. An independent observer radiographicallyanalyzed the preoperative and immediate postoperative studies. Spacerposition was classified from anterior to posterior, medial to lateral as wellas obliquity with respect to the end plates. Difference in segmental lordosiswas correlated with the spacer position.RESULTS: The analysis of the data showed that the more anterior thegraft, the more lordosis was gained. In the five groups starting from the mostposterior to the most anterior, the average postoperative change in lordosisvaried from zero to 6 degrees, with a direct relationship to how anteriorthe position of the graft. This relationship had a correlation coefficient of.96, with regression on the line created having an r-squared value of .93.CONCLUSIONS: While only addressing immediate postoperative changein lordosis, the data show a compelling correlation between the degree ofanterior graft placement with the amount of final lordosis achieved. Futuredirections include more numbers, long-term change in lordosis, and subjec-tive patient outcomes.DISCLOSURES: No disclosures.CONFLICT OF INTEREST: Author (JF, FS) Consultant: MedtronicSofamor Danek.

doi: 10.1016/j.spinee.2005.05.197