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88. Outcomes of DBM use within interbody fusion cages: an adequate autograft substitute?
Proceedings of the NASS 18th Annual Meeting / The Spine Journal 3 (2003) 67S–171S RNFA, consultant; Medtronic Sofamor Danek. Thomas Whitecloud III, MD, Warren Roesch, RNFA, stockholders: minimal stock, mostly through mutual funds. doi: 10.1016/S1529-9430(03)00270-5 1:46 88. Outcomes of DBM use within interbody fusion cages: an adequate autograft substitute? Keith Maxwell, MD1; 1Southeastern Sports Medicine, Asheville, NC, USA HYPOTHESIS: The use of autograft within cages remains the gold standard for use in the treatment of degenerative disc disease. However, harvesting from the iliac crest requires a second procedure, which can lead to extended pain and complications. New technologies have emerged in hopes of finding an adequate replacement for autograft, which would eliminate the necessity of harvesting and still maintain the high rates of fusion. Demineralized bone matrix is often used in conjunction with autograft to add an osteoconductive element and increase the chances of fusion, however, the use of DBMs as an autograft replacement within cages has not been studied. With the emergence of BMPs, which are costly, and have yet to be proven superior to autograft, it is of interest to determine the effectiveness of DBMs as autograft replacements within IF cages. METHODS: A cohort of 51 consecutive patients was reviewed. These patients were all treated for degenerative disc disease using interbody fusion cages (BAK/L) filled with demineralized bone matrix (Grafton/ ProOsteon mix) in one or two level procedures. A total of 20 ccs of demineralized bone matrix filled each cage. A chart review including patient history, demographics, surgical details, complications, and fusion status was completed on each patient. In addition, patients were contacted via telephone to determine surgical outcome and overall satisfaction. RESULTS: This patient population consisted of 24 males (47%), 27 females (53%), and 24 smokers (47%) with a mean age of 44 years (24– 67). Six percent (6%) of the patients were receiving worker’s compensation. All patients were at least one year post-index. Mean time from surgery was 2.72 years. Operative levels included L3-4 (2), L4-5 (21), and L5-S1 (37) with 42 (82%) one-level procedures and 9 (18%) two-level procedures. Mean estimated blood loss, length of surgery, and length of hospitalization were 156cc (15–1250 cc), 145 min (120–240 min), and 2.5 days (0–10 days), respectively. Back and leg pain scores both improved significantly following surgery (p⬍0.001) from mean scores of 85.3 and 78.9 to 40.8 and 41.2. Fusion occurred in 45 patients (96%), 4 patients could not be assessed, 1 patient remained unfused, and 1 patient developed a pseudoarthrosis. Mean time to fusion was 12 months. No correlations were detected between smoking status and time to fusion or change in back and leg pain. All reported compensation patients returned to work (full or part time)following surgery. Results of the initial telephone survey indicate 84% of the patients would recommend this surgery and 72% agree that surgery met their expectations or that it has helped enough that they would go through it again for the same outcome. Intraoperative complications included 2 left iliac vein lacerations (4%). There were 14 postoperative complications (26%) resulting in 3 revisions (6%). DISCUSSION: DBMs appear to effectively promote bone formation within interbody fusion cages. Resulting fusion rates from this study are comparable to autograft and BMP rates in the literature. Complications related to the cage/DBM construct are similar to complications often noted with cage/ autograft constructs. CONCLUSIONS: Demineralized bone graft appears to be an effective replacement for autograft within cages, providing an osteoconductive element that results in comparable fusion rates. Results from this study indicate that DBMs may be less expensive, equally effective alternatives to BMPs. DISCLOSURES: Device or drug: BAK/L Interbody fusion system. Status: approved. Device or drug: Grafton. Status: approved. Device or drug: ProOsteon. Status: approved. CONFLICT OF INTEREST: Gwen Gimmestad, BA; other support: employee of Centerpulse Spine-Tech Inc. doi: 10.1016/S1529-9430(03)00271-7
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1:53 89. Prospective study of the cantilever transforaminal lumbar interbody fusion (c-TLIF): radiographic and patient outcomes with a minimum of two years follow-up James Schwender, MD1, James Ogilvie, MD1; 1Twin Cities Spine Center, Minneapolis, MN, USA HYPOTHESIS: The Cantilever-Transforaminal Lumbar Interbody Fusion (c-TLIF) differs from other transforaminal techniques by placing structural allograft bone along the anterior column apophyseal ring providing immediate interbody support. Local autologous bone is placed in the middle column for osteo-integration. It achieves circumferential fusion with no need for iliac crest bone graft, nerve or dural retraction, or posterolateral dissection for inter-transverse fusion. This study prospectively evaluated 54 consecutive patients with minimum of two-year follow-up undergoing c-TLIF to determine its safety and efficacy in treating symptomatic disc disease and spondylolisthesis requiring lumbar arthrodesis. METHODS: The c-TLIF utilizes a semi-lunar femoral ring allograft placed midline and ventral against the intact anterior annular fibers along the anterior column apophyseal ring followed by local autologous graft placed in the middle column. Compression across pedicle screw instrumentation, using the structural allograft as a fulcrum, creates restoration of lordosis and places the autologous bone under compression. The contra-lateral facet is packed with bone graft. No posterolateral grafting or iliac crest bone harvesting is required. RESULTS: Fifty-four patients were followed prospectively for a minimum of 2 years. Twenty-six (48%) had one-level fusions, 22 (41%) had twolevel procedures, while the remaining 6 (11%) patients had a three-level procedure, for a total of 88 levels treated. Twenty (37%) had previous lumbar surgery. Forty (74%) of the patients had degenerative disc disease as the primary diagnosis, while the remaining fourteen patient’s diagnosis was spondylolisthesis. Solid fusion was achieved in 49 (94%)of the patients based on plain radiographic criteria. Three symptomatic pseudoarthroses were revised and subsequently achieved solid fusion. Revision surgery was required in four additional patients: one resulting from graft extrusion into the foramen, two others from inadequate decompression and one deep wound infection. No dural lacerations occurred. No instrumentation complications were encountered. Lordosis was maintained or increased in all patients (average change 3 degrees per level; p⬍0.001). Patient functionality was improved from pre-operative to follow-up as measured by the RolandMorris (average 6 pt change, p⬍0.001). Statistically significant improvements from prior to surgery were also noted in physical functionality, physical role, pain, vitality and social function, as measured by the subscales of the SF-36 (p⬍0.05 for each). Overall, seventy-four percent (91% in spondylolisthesis) were satisfied with surgical treatment and 78% (91% in spondylolisthesis) would have the surgery again. DISCUSSION: The cantilever-TLIF procedure allows circumferential lumbar fusion without the need for iliac crest bone graft, posterolateral fusion, anterior abdominal exposure or nerve and dural retraction. This technique’s most substantial contributions are immediate anterior column structural support, the placement of the interbody local autologous bone graft under a compressive load due to the cantilever principle and the ability to maintain or restore lordosis. CONCLUSIONS: Fusion rate was comparable to other interbody techniques without the associated morbidity. Outcome measurements demonstrate relatively high patient satisfaction (74%) and statistically significant improvements in parameters of physical and social function. DISCLOSURES: Device or drug: cantilever-transforaminal lumbar interbody fusion. Status: approved. CONFLICT OF INTEREST: No conflicts. doi: 10.1016/S1529-9430(03)00272-9 2:00 90. The effect of preoperative disc space height on clinical outcomes after anterior lumbar interbody fusion
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1:53 89. Prospective study of the cantilever transforaminal lumbar interbody fusion (c-TLIF): radiographic and patient outcomes with a minimum of two years follow-up James Schwender, MD1, James Ogilvie, MD1; 1Twin Cities Spine Center, Minneapolis, MN, USA HYPOTHESIS: The Cantilever-Transforaminal Lumbar Interbody Fusion (c-TLIF) differs from other transforaminal techniques by placing structural allograft bone along the anterior column apophyseal ring providing immediate interbody support. Local autologous bone is placed in the middle column for osteo-integration. It achieves circumferential fusion with no need for iliac crest bone graft, nerve or dural retraction, or posterolateral dissection for inter-transverse fusion. This study prospectively evaluated 54 consecutive patients with minimum of two-year follow-up undergoing c-TLIF to determine its safety and efficacy in treating symptomatic disc disease and spondylolisthesis requiring lumbar arthrodesis. METHODS: The c-TLIF utilizes a semi-lunar femoral ring allograft placed midline and ventral against the intact anterior annular fibers along the anterior column apophyseal ring followed by local autologous graft placed in the middle column. Compression across pedicle screw instrumentation, using the structural allograft as a fulcrum, creates restoration of lordosis and places the autologous bone under compression. The contra-lateral facet is packed with bone graft. No posterolateral grafting or iliac crest bone harvesting is required. RESULTS: Fifty-four patients were followed prospectively for a minimum of 2 years. Twenty-six (48%) had one-level fusions, 22 (41%) had twolevel procedures, while the remaining 6 (11%) patients had a three-level procedure, for a total of 88 levels treated. Twenty (37%) had previous lumbar surgery. Forty (74%) of the patients had degenerative disc disease as the primary diagnosis, while the remaining fourteen patient’s diagnosis was spondylolisthesis. Solid fusion was achieved in 49 (94%)of the patients based on plain radiographic criteria. Three symptomatic pseudoarthroses were revised and subsequently achieved solid fusion. Revision surgery was required in four additional patients: one resulting from graft extrusion into the foramen, two others from inadequate decompression and one deep wound infection. No dural lacerations occurred. No instrumentation complications were encountered. Lordosis was maintained or increased in all patients (average change 3 degrees per level; p⬍0.001). Patient functionality was improved from pre-operative to follow-up as measured by the RolandMorris (average 6 pt change, p⬍0.001). Statistically significant improvements from prior to surgery were also noted in physical functionality, physical role, pain, vitality and social function, as measured by the subscales of the SF-36 (p⬍0.05 for each). Overall, seventy-four percent (91% in spondylolisthesis) were satisfied with surgical treatment and 78% (91% in spondylolisthesis) would have the surgery again. DISCUSSION: The cantilever-TLIF procedure allows circumferential lumbar fusion without the need for iliac crest bone graft, posterolateral fusion, anterior abdominal exposure or nerve and dural retraction. This technique’s most substantial contributions are immediate anterior column structural support, the placement of the interbody local autologous bone graft under a compressive load due to the cantilever principle and the ability to maintain or restore lordosis. CONCLUSIONS: Fusion rate was comparable to other interbody techniques without the associated morbidity. Outcome measurements demonstrate relatively high patient satisfaction (74%) and statistically significant improvements in parameters of physical and social function. DISCLOSURES: Device or drug: cantilever-transforaminal lumbar interbody fusion. Status: approved. CONFLICT OF INTEREST: No conflicts. doi: 10.1016/S1529-9430(03)00272-9 2:00 90. The effect of preoperative disc space height on clinical outcomes after anterior lumbar interbody fusion