- Email: [email protected]
Local Bone Graft Harvesting with Careful Facet Arthodesis in Posterolateral Lumbar Fusion: Outcomes and Morbidity Compared with AMPLIFY Trial Data
60S
Proceedings of the NASS 26th Annual Meeting / The Spine Journal 11 (2011) 1S–173S
rhBMP-7 led to variable outcomes (64% fusion). The lowest dose of rhBMP-2 utilized that healed the rat spine was 3 ug. CONCLUSIONS: Pre-clinical animal models are instrumental in the study of spinal biologics to demonstrate safety and efficacy before application to humans. The rat posterolateral intertransverse spinal arthrodesis model represents an inexpensive, practical, and applicable environment to study the success of different biologic products in bone healing. This meta-analysis demonstrates the strong reliability of this model when control (sham, autograft, collagen sponge) and treatment groups (rhBMP-2, genetically manipulated cells) are used. For bone graft substitutes that are less potent such as DBM, fusion rates at 8-week time points should be used. For gene therapy and rhBMP-2, a 3- or 4-week endpoint can be used with confidence. Future study designs which utilize this model may be improved with this data including the possible elimination of redundant control groups, dose of growth factor, and choice of cell-based therapies. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs. doi: 10.1016/j.spinee.2011.08.151
115. Does Iliac Crest Autograft Affect the Outcome of Fusion in the Setting of Degenerative Spondylolisthesis? A Subgroup Analysis of the SPORT Study Kris Radcliff, MD1, Raymond Hwang, MD, MS, MBA2, Alan Hilibrand, MD3, Harvey Smith, MD4, Jordan Gruskay3, Jon D. Lurie, MD5, Wenyan Zhao6, Todd Albert, MD3, James Weinstein, DO7; 1Ben Franklin House, Egg Harbor Township, NJ, USA; 2Cambridge, MA, USA; 3Rothman Institute, Philadelphia, PA, USA; 4New England Orthopaedic & Spine Surgery, Chestnut Hill, MA, USA; 5Dartmouth College, Lebanon, NH, USA; 6Hanover, NH, USA; 7Dartmouth Hitchcock Medical Center, Lebanon, NH, USA BACKGROUND CONTEXT: The SPORT trial is a prospective, multicenter study of surgical treatment versus nonoperative treatment for lumbar degenerative conditions. There is considerable controversy about the long-term morbidity of autologous local iliac crest bone graft versus bone graft substitutes. PURPOSE: The hypothesis of this study is that there is no long term difference in outcome in patients who underwent posterior lumbar fusion with iliac crest bone graft compared to non-iliac crest bone graft. STUDY DESIGN/SETTING: Randomized controlled trial. PATIENT SAMPLE: 354 patients. OUTCOME MEASURES: Short Form-36 (SF36), Oswestry Disability Index (ODI), Sciatica Bothersomeness Index. METHODS: The study population includes patients enrolled in the degenerative spondylolisthesis (DS) cohort of SPORT who underwent fusion. Patients were divided according to whether or not they underwent autologous iliac crest autograft. RESULTS: There were 108 patients who had fusion with iliac crest autograft (ICBG) and 246 non-iliac crest autograft (No–ICBG). There were no baseline demographic differences between groups. There was an increased percentage in the ICBG group of neurological defict (ICBG 65% vs NoICBG 50%, p5.011), asymmetric depressed reflexes (35% vs 22%, p5.017), and neuroforaminal stenosis (51% vs 39%, p5.041). There was an increased percentage of multilevel fusions in the ICBG (32% vs 21%, p5.033), L5-S1 decompression (38% vs 26%, p5.031). Operative time was increased in the ICBG group (233.4 vs 200.9 minutes, p!.001), and there was a trend toward increased blood loss (686.0 vs 582.3, p5.057). There were no differences in postoperative complications including infection or revision rate between groups. There were no significant differences in SF36 score, ODI, stenosis bothersomeness index, low back pain bothersomeness index, or percent satisfaction with symptoms between ICBG and NoICBG groups at 4 years or averaged over the study period. CONCLUSIONS: ICBG was not shown to be associated with an improvement in outcome or reduction in revision rate in degenerative spondylolisthesis. However, the complications of ICBG were not significantly
different from No-ICBG surgery, suggesting that its use is not associated with long term reduction in outcome. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs. doi: 10.1016/j.spinee.2011.08.152
116. Local Bone Graft Harvesting with Careful Facet Arthodesis in Posterolateral Lumbar Fusion: Outcomes and Morbidity Compared with AMPLIFY Trial Data Eugene Carragee, MD1, Kyle Mitsunaga, MD2, Joshua Abrams, DO3, Gaetano Scuderi, MD4; 1Stanford University School of Medicine, Redwood City, CA, USA; 2Stanford University, Department of Orthopedic Surgery, Redwood City, CA, USA; 3Foster City, CA, USA; 4Jupiter, FL, USA BACKGROUND CONTEXT: Local bone graft is often harvested in short-segment posterolateral (PL) lumbar fusion techniques. This technique was excluded from the AMPLYFY (rhBMP-2) FDA trial. Facet arthrodesis, usually a standard requirement in PL was not required or assessed in the AMPLIFY trial. Industry-sponsored trial designs promoting rhBMP-2 grafting techniques have assumed the volume of local bone graft obtained in PL fusion is negligible. This has not been studied to date. It is possible that using local bone graft, and iliac crest BG only as needed along with careful facet fusion would improved the so-called ‘‘control group outcomes’’ to equivalence or superiority to the AMPLIFY group. PURPOSE: To assess the adequacy of local bone graft harvesting volumes in PLF surgery in degenerative conditions, the frequency of need for ICBG augmentation, and the fusion outcomes using this technique with careful facet arthrodesis, compared against the FDA AMPLIFY data. STUDY DESIGN/SETTING: Consecutive cohort s of patients with single level degenerative fusions using local and as needed ICBG compared to FDA data of similar patients. PATIENT SAMPLE: 45 consecutive subjects undergoing one level decompression and posterolateral fusions for degenerative fusions. Subjects excluded included a previous attempt at fusion at the intended surgical level, use of medications that interfere with fusion, osteoporosis confirmed by a bone densitometry scan, autoimmune disease, a malignant tumor, infection, pregnancy, or the inability to harvest ICBG. These were compared against historical cohort of rhBMP-2 patients in FDA AMPLIFY trial data with similar selection criteria. OUTCOME MEASURES: VAS, ODI, medication usage, employment status, fusion assessment, ICBG harvesting site painfulness (if used), ad global satisfaction ratings. METHODS: A consecutive cohort of lumbar fusion patients (1 level) were followed with close outcomes measuress, matching the outcomes collected in the FDA trial. RESULTS: 38 of 45 (84%) patients had full follow-up for two years. The mean volume of harvested local bone was 24 cc (range 16 cc to 39 cc) Additional ICBG was used in 17 patients (if local bone was less than 25 cc). At early time-points (6 weeks, 12 weeks) the local bone graft6ICBG group either trended better or were significantly better in pain and functional outcome than the rhBMP-2 AMPLYFY controls. At later time points (6 months, 1 and 2 years) there was no difference. Early back pain and leg pain adverse events were significantly less than in AMPLIFY subjects (6 weeks; p5.02; 12 weeks p5.05). Fusion rate at 2 years was 91%. Patients could not identify side of ICBG harvesting if this had been done: of 17 patients with ICBG harvesting, 7 indicated either no pain or equal pain on either, 4 identified greater pain on the side contralateral to the harvest, and 6 identified pain greater on the ipsilateral site of harvesting: that is there was no demonstrable long-term ICBG harvesting morbidity. CONCLUSIONS: Posterolateral fusion using local BG, with or without small quantities of ICBG, in combination with a meticulous facet arthrodesis yielded equivalent or superior results to the detailed historical data of rhBMP-2 use in the AMPLIFY trial. The increased operative time was negligible. The cost-savings was large high including the AMPLIFY
All referenced figures and tables will be available at the Annual Meeting and will be included with the post-meeting online content.
Proceedings of the NASS 26th Annual Meeting / The Spine Journal 11 (2011) 1S–173S
61S
projected costs ($5-10,000 USD) as well as incidental costs of early pain complications. Virtually no 12 or 24 month pain morbidity was seen in subjects requiring ICBG harvesting in contradistinction to the over-estimated ICBG morbidity (60% with persistent pain) published by the AMPLIFY (rhBMP-2) study authors. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs.
118. rhBMP-2 in TLIF: Dose Related Complications from a Large Series Dennis Crandall, MD1, Jason Patterson, MD2, Eric Huish3, Jan Revella, RN1, Jason Datta, MD1, Michael Chang, MD4, Terrence Crowder, MD1, Ryan McLemore, PhD2; 1Sonoran Spine Center, Mesa, AZ, USA; 2Banner Samaritan Hospital Orthopaedic Residency, Phoenix, AZ, USA; 3Gilbert, AZ, USA; 4Phoenix, AZ, USA
doi: 10.1016/j.spinee.2011.08.153
BACKGROUND CONTEXT: The complications from TLIF with cage and BMP have been described with varying doses of BMP. The largest series in the literature reports on 204 patients with 3 months follow-up. PURPOSE: To analyze the complications and outcomes from a large series of patients undergoing TLIF with BMP in order to propose the optimal BMP dosage for arthrodesis with the least complications. This is the largest report of TLIF with BMP with the longest follow-up. STUDY DESIGN/SETTING: A retrospective review of prospectively collected clinical and radiographic data from a spine surgery database. PATIENT SAMPLE: 451 consecutive adults underwent open posterior instrumented fusion (PSF) with TLIF, PEEK cage, and rhBMP-2; Diagnosis: degenerative-195, spondylolisthesis-150, scoliosis-101, kyphosis-5. Patient age averaged 60 years (range 19–91 years); 51 smokers, 182 had prior decompression/fusion. OUTCOME MEASURES: VAS pain scores, Oswestry Disability Index (ODI), pain medication records, and radiographic imaging pre-op, 1 year, 2 years, and latest follow-up. Fusion was defined as bridging interspace bone, no loosening of instrumentation, no motion on flexion-extension radiographs. METHODS: All patients underwent PSF with local autograft and corticocancellous allograft at average 4.4 levels (range 2-17 levels); TLIF in all patients averaged 1.7 levels (range 1-4 levels), with1 level-202, 2 levels180, 3 levels-66, 4 levels-4. Each TLIF was supported by a rectangular PEEK cage filled with autograft and the disc was backfilled with local autograft around the cage. Interbody BMP averaged 8.2 mg/disc (range 4-12 mg/disc) in a total of 775 discs, and was inserted deep to the cage prior to cage placement. RESULTS: At average 4 years follow-up (range 24–86 months), Nonunions: 8 patients (8/775 discs; 3 scoliosis, 1 spondy, 4 degen), 1 at L3/ 4, 1 at L4/5, 6 at L5-S1. Nonunion BMP dose: 12 mg-1, 8 mg-4, 6 mg2, 4 mg-1. Five underwent revision surgery for nonunion repair. Possible BMP related complications: seroma-4, bony overgrowth-6, (all used 68mgBMP/disc, all resolved with decompression). Complications were too infrequent to be statistically related to BMP dose. Other complications: adjacent degeneration-142(18 revised), adjacent fracture-28(9 revised), infection-14, late instrumentation removal-9. Significant improvement was noted in VAS (pre-op-6.2, 2 yr-3.1, p!.001) and ODI (pre-50, 2 yr-28, p!.001), and pain medication requirements. CONCLUSIONS: Instrumented posterior spinal fusion with TLIF, PEEK cage, and BMP-2 produces reliable fusion (99%) and improved clinical outcomes in adults requiring arthrodesis. Most complications occurred in deformity patients; BMP related complications were uncommon, none at 4 mg/disc dose. The optimal dose of BMP to avoid seromas and bone overgrowth without increasing the risk of pseudarthrosis appears to be 4 mg/ disc. FDA DEVICE/DRUG STATUS: rhBMP-2 in TLIF: Not approved for this indication.
117. Biomaterial Impregnation with Bone Marrow Aspirate: Does it Live Up to the Promise? Claudia Eder, MD1, Alexander Tuschel, MD2, Michael Ogon, MD3; 1 Orthop€ adisches Hospital Speising, Austria; 2Vienna, Austria; 3 Orthopaedisches Spital Speising Gmbh, Wien, Austria BACKGROUND CONTEXT: The limited supply of autografts for spinal fusion has prompted extensive research on bone graft substitutes. So far, various biomaterials have been applied either stand alone or impregnated with blood or bone marrow aspirate to promote spinal fusion. Bone marrow aspirate harvested from the iliac crest is known to contain osteoprogenitor cells, which are supposed to differentiate into osteoblasts and form new bone at the desired fusion site. PURPOSE: But according to literature, only 0.001%–0.01% of bone marrow aspirate cells are in fact osteoprogenitor cells (Science 1999;248:143). So are we really implanting what we think we are? Aim of the presented study is to investigate the stem cell concentration and delivery obtained after biomaterial perfusion with bone marrow aspirate. STUDY DESIGN/SETTING: In vitro study. PATIENT SAMPLE: Samples from 3 different patients were used and 9 biomaterials of each type were prepared per bone marrow aspirate. HETCAM experiments were performed in triplicates. OUTCOME MEASURES: Cell seeding density within the biomaterial and angionenesis after in vivo transplantation were assessed using histomorphometrycal methods. METHODS: Surplus material remaining after cage and intervertebral space preparation for routine spinal fusion surgery was analyzed. Three different biomaterials (demineralised bone matrix - DBX, ChronOSÒ and HealOSÒ were impregnated according to specifications of the supplyer. The cell seeded biomaterials were fixed in 4% paraformaldehyde and processed for histological analysis. Stem cell density was assessed after H/E and May Gruenwald staining using an Olympus IX-71 microscope and cellF analysis software. To investgate in vivo effects, cell seeded biomaterials were tranplanted onto the chick chorionallantoic membrane model and biomaterial integration, cell distribution and angiogenesis were evaluated. RESULTS: Most of the cells in bone marrow aspirate were identified as erythrocytes while only a small fraction was identified as nucleated stem cells. After biomaterial impregnation, average stem cell density was 1,13 cells/mm2 (ChronOSÒ), 0.92 cells/mm2 (HealOSÒ) and 0.008 cells/ mm2 (DBX). Only the marginal pores of the biomaterials were filled with cells (mostly erythrocytes) after biomaterial implantation. Despite the poor cell yield, the cell impregnated biomaterials were able to stimulate angiogenesis in the CAM-Model. CONCLUSIONS: Impregnation of biomaterials with bone marrow aspirate can only deliver very small amounts of osteoprogenitor cells to the implantation site. Although these constructs are able to stimulate angiogenesis, the number of osteoprogenotor cells delivered seems to small to have a significant effect on osteogenesis. Increasing cell density by centrifugation or expansion in culture might therefore be required to improve fusion results. FDA DEVICE/DRUG STATUS: Demineralized bone matrix: Approved for this indication; ChronOS: Approved for this indication; HealOS: Approved for this indication. doi: 10.1016/j.spinee.2011.08.154
doi: 10.1016/j.spinee.2011.08.155
119. Recombinant Human Bone Morphogenetic Protein-2 (rhBMP-2) in Posterolateral Lumbar Spine Fusion: Complications in the Elderly Martin Hoffmann, MD, Clifford B. Jones, MD; Grand Rapids, MI, USA BACKGROUND CONTEXT: rhBMP-2 (INFUSE) has been utilized off label for instrumented lumbar posterolateral fusions for many
All referenced figures and tables will be available at the Annual Meeting and will be included with the post-meeting online content.
Proceedings of the NASS 26th Annual Meeting / The Spine Journal 11 (2011) 1S–173S
rhBMP-7 led to variable outcomes (64% fusion). The lowest dose of rhBMP-2 utilized that healed the rat spine was 3 ug. CONCLUSIONS: Pre-clinical animal models are instrumental in the study of spinal biologics to demonstrate safety and efficacy before application to humans. The rat posterolateral intertransverse spinal arthrodesis model represents an inexpensive, practical, and applicable environment to study the success of different biologic products in bone healing. This meta-analysis demonstrates the strong reliability of this model when control (sham, autograft, collagen sponge) and treatment groups (rhBMP-2, genetically manipulated cells) are used. For bone graft substitutes that are less potent such as DBM, fusion rates at 8-week time points should be used. For gene therapy and rhBMP-2, a 3- or 4-week endpoint can be used with confidence. Future study designs which utilize this model may be improved with this data including the possible elimination of redundant control groups, dose of growth factor, and choice of cell-based therapies. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs. doi: 10.1016/j.spinee.2011.08.151
115. Does Iliac Crest Autograft Affect the Outcome of Fusion in the Setting of Degenerative Spondylolisthesis? A Subgroup Analysis of the SPORT Study Kris Radcliff, MD1, Raymond Hwang, MD, MS, MBA2, Alan Hilibrand, MD3, Harvey Smith, MD4, Jordan Gruskay3, Jon D. Lurie, MD5, Wenyan Zhao6, Todd Albert, MD3, James Weinstein, DO7; 1Ben Franklin House, Egg Harbor Township, NJ, USA; 2Cambridge, MA, USA; 3Rothman Institute, Philadelphia, PA, USA; 4New England Orthopaedic & Spine Surgery, Chestnut Hill, MA, USA; 5Dartmouth College, Lebanon, NH, USA; 6Hanover, NH, USA; 7Dartmouth Hitchcock Medical Center, Lebanon, NH, USA BACKGROUND CONTEXT: The SPORT trial is a prospective, multicenter study of surgical treatment versus nonoperative treatment for lumbar degenerative conditions. There is considerable controversy about the long-term morbidity of autologous local iliac crest bone graft versus bone graft substitutes. PURPOSE: The hypothesis of this study is that there is no long term difference in outcome in patients who underwent posterior lumbar fusion with iliac crest bone graft compared to non-iliac crest bone graft. STUDY DESIGN/SETTING: Randomized controlled trial. PATIENT SAMPLE: 354 patients. OUTCOME MEASURES: Short Form-36 (SF36), Oswestry Disability Index (ODI), Sciatica Bothersomeness Index. METHODS: The study population includes patients enrolled in the degenerative spondylolisthesis (DS) cohort of SPORT who underwent fusion. Patients were divided according to whether or not they underwent autologous iliac crest autograft. RESULTS: There were 108 patients who had fusion with iliac crest autograft (ICBG) and 246 non-iliac crest autograft (No–ICBG). There were no baseline demographic differences between groups. There was an increased percentage in the ICBG group of neurological defict (ICBG 65% vs NoICBG 50%, p5.011), asymmetric depressed reflexes (35% vs 22%, p5.017), and neuroforaminal stenosis (51% vs 39%, p5.041). There was an increased percentage of multilevel fusions in the ICBG (32% vs 21%, p5.033), L5-S1 decompression (38% vs 26%, p5.031). Operative time was increased in the ICBG group (233.4 vs 200.9 minutes, p!.001), and there was a trend toward increased blood loss (686.0 vs 582.3, p5.057). There were no differences in postoperative complications including infection or revision rate between groups. There were no significant differences in SF36 score, ODI, stenosis bothersomeness index, low back pain bothersomeness index, or percent satisfaction with symptoms between ICBG and NoICBG groups at 4 years or averaged over the study period. CONCLUSIONS: ICBG was not shown to be associated with an improvement in outcome or reduction in revision rate in degenerative spondylolisthesis. However, the complications of ICBG were not significantly
different from No-ICBG surgery, suggesting that its use is not associated with long term reduction in outcome. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs. doi: 10.1016/j.spinee.2011.08.152
116. Local Bone Graft Harvesting with Careful Facet Arthodesis in Posterolateral Lumbar Fusion: Outcomes and Morbidity Compared with AMPLIFY Trial Data Eugene Carragee, MD1, Kyle Mitsunaga, MD2, Joshua Abrams, DO3, Gaetano Scuderi, MD4; 1Stanford University School of Medicine, Redwood City, CA, USA; 2Stanford University, Department of Orthopedic Surgery, Redwood City, CA, USA; 3Foster City, CA, USA; 4Jupiter, FL, USA BACKGROUND CONTEXT: Local bone graft is often harvested in short-segment posterolateral (PL) lumbar fusion techniques. This technique was excluded from the AMPLYFY (rhBMP-2) FDA trial. Facet arthrodesis, usually a standard requirement in PL was not required or assessed in the AMPLIFY trial. Industry-sponsored trial designs promoting rhBMP-2 grafting techniques have assumed the volume of local bone graft obtained in PL fusion is negligible. This has not been studied to date. It is possible that using local bone graft, and iliac crest BG only as needed along with careful facet fusion would improved the so-called ‘‘control group outcomes’’ to equivalence or superiority to the AMPLIFY group. PURPOSE: To assess the adequacy of local bone graft harvesting volumes in PLF surgery in degenerative conditions, the frequency of need for ICBG augmentation, and the fusion outcomes using this technique with careful facet arthrodesis, compared against the FDA AMPLIFY data. STUDY DESIGN/SETTING: Consecutive cohort s of patients with single level degenerative fusions using local and as needed ICBG compared to FDA data of similar patients. PATIENT SAMPLE: 45 consecutive subjects undergoing one level decompression and posterolateral fusions for degenerative fusions. Subjects excluded included a previous attempt at fusion at the intended surgical level, use of medications that interfere with fusion, osteoporosis confirmed by a bone densitometry scan, autoimmune disease, a malignant tumor, infection, pregnancy, or the inability to harvest ICBG. These were compared against historical cohort of rhBMP-2 patients in FDA AMPLIFY trial data with similar selection criteria. OUTCOME MEASURES: VAS, ODI, medication usage, employment status, fusion assessment, ICBG harvesting site painfulness (if used), ad global satisfaction ratings. METHODS: A consecutive cohort of lumbar fusion patients (1 level) were followed with close outcomes measuress, matching the outcomes collected in the FDA trial. RESULTS: 38 of 45 (84%) patients had full follow-up for two years. The mean volume of harvested local bone was 24 cc (range 16 cc to 39 cc) Additional ICBG was used in 17 patients (if local bone was less than 25 cc). At early time-points (6 weeks, 12 weeks) the local bone graft6ICBG group either trended better or were significantly better in pain and functional outcome than the rhBMP-2 AMPLYFY controls. At later time points (6 months, 1 and 2 years) there was no difference. Early back pain and leg pain adverse events were significantly less than in AMPLIFY subjects (6 weeks; p5.02; 12 weeks p5.05). Fusion rate at 2 years was 91%. Patients could not identify side of ICBG harvesting if this had been done: of 17 patients with ICBG harvesting, 7 indicated either no pain or equal pain on either, 4 identified greater pain on the side contralateral to the harvest, and 6 identified pain greater on the ipsilateral site of harvesting: that is there was no demonstrable long-term ICBG harvesting morbidity. CONCLUSIONS: Posterolateral fusion using local BG, with or without small quantities of ICBG, in combination with a meticulous facet arthrodesis yielded equivalent or superior results to the detailed historical data of rhBMP-2 use in the AMPLIFY trial. The increased operative time was negligible. The cost-savings was large high including the AMPLIFY
All referenced figures and tables will be available at the Annual Meeting and will be included with the post-meeting online content.
Proceedings of the NASS 26th Annual Meeting / The Spine Journal 11 (2011) 1S–173S
61S
projected costs ($5-10,000 USD) as well as incidental costs of early pain complications. Virtually no 12 or 24 month pain morbidity was seen in subjects requiring ICBG harvesting in contradistinction to the over-estimated ICBG morbidity (60% with persistent pain) published by the AMPLIFY (rhBMP-2) study authors. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs.
118. rhBMP-2 in TLIF: Dose Related Complications from a Large Series Dennis Crandall, MD1, Jason Patterson, MD2, Eric Huish3, Jan Revella, RN1, Jason Datta, MD1, Michael Chang, MD4, Terrence Crowder, MD1, Ryan McLemore, PhD2; 1Sonoran Spine Center, Mesa, AZ, USA; 2Banner Samaritan Hospital Orthopaedic Residency, Phoenix, AZ, USA; 3Gilbert, AZ, USA; 4Phoenix, AZ, USA
doi: 10.1016/j.spinee.2011.08.153
BACKGROUND CONTEXT: The complications from TLIF with cage and BMP have been described with varying doses of BMP. The largest series in the literature reports on 204 patients with 3 months follow-up. PURPOSE: To analyze the complications and outcomes from a large series of patients undergoing TLIF with BMP in order to propose the optimal BMP dosage for arthrodesis with the least complications. This is the largest report of TLIF with BMP with the longest follow-up. STUDY DESIGN/SETTING: A retrospective review of prospectively collected clinical and radiographic data from a spine surgery database. PATIENT SAMPLE: 451 consecutive adults underwent open posterior instrumented fusion (PSF) with TLIF, PEEK cage, and rhBMP-2; Diagnosis: degenerative-195, spondylolisthesis-150, scoliosis-101, kyphosis-5. Patient age averaged 60 years (range 19–91 years); 51 smokers, 182 had prior decompression/fusion. OUTCOME MEASURES: VAS pain scores, Oswestry Disability Index (ODI), pain medication records, and radiographic imaging pre-op, 1 year, 2 years, and latest follow-up. Fusion was defined as bridging interspace bone, no loosening of instrumentation, no motion on flexion-extension radiographs. METHODS: All patients underwent PSF with local autograft and corticocancellous allograft at average 4.4 levels (range 2-17 levels); TLIF in all patients averaged 1.7 levels (range 1-4 levels), with1 level-202, 2 levels180, 3 levels-66, 4 levels-4. Each TLIF was supported by a rectangular PEEK cage filled with autograft and the disc was backfilled with local autograft around the cage. Interbody BMP averaged 8.2 mg/disc (range 4-12 mg/disc) in a total of 775 discs, and was inserted deep to the cage prior to cage placement. RESULTS: At average 4 years follow-up (range 24–86 months), Nonunions: 8 patients (8/775 discs; 3 scoliosis, 1 spondy, 4 degen), 1 at L3/ 4, 1 at L4/5, 6 at L5-S1. Nonunion BMP dose: 12 mg-1, 8 mg-4, 6 mg2, 4 mg-1. Five underwent revision surgery for nonunion repair. Possible BMP related complications: seroma-4, bony overgrowth-6, (all used 68mgBMP/disc, all resolved with decompression). Complications were too infrequent to be statistically related to BMP dose. Other complications: adjacent degeneration-142(18 revised), adjacent fracture-28(9 revised), infection-14, late instrumentation removal-9. Significant improvement was noted in VAS (pre-op-6.2, 2 yr-3.1, p!.001) and ODI (pre-50, 2 yr-28, p!.001), and pain medication requirements. CONCLUSIONS: Instrumented posterior spinal fusion with TLIF, PEEK cage, and BMP-2 produces reliable fusion (99%) and improved clinical outcomes in adults requiring arthrodesis. Most complications occurred in deformity patients; BMP related complications were uncommon, none at 4 mg/disc dose. The optimal dose of BMP to avoid seromas and bone overgrowth without increasing the risk of pseudarthrosis appears to be 4 mg/ disc. FDA DEVICE/DRUG STATUS: rhBMP-2 in TLIF: Not approved for this indication.
117. Biomaterial Impregnation with Bone Marrow Aspirate: Does it Live Up to the Promise? Claudia Eder, MD1, Alexander Tuschel, MD2, Michael Ogon, MD3; 1 Orthop€ adisches Hospital Speising, Austria; 2Vienna, Austria; 3 Orthopaedisches Spital Speising Gmbh, Wien, Austria BACKGROUND CONTEXT: The limited supply of autografts for spinal fusion has prompted extensive research on bone graft substitutes. So far, various biomaterials have been applied either stand alone or impregnated with blood or bone marrow aspirate to promote spinal fusion. Bone marrow aspirate harvested from the iliac crest is known to contain osteoprogenitor cells, which are supposed to differentiate into osteoblasts and form new bone at the desired fusion site. PURPOSE: But according to literature, only 0.001%–0.01% of bone marrow aspirate cells are in fact osteoprogenitor cells (Science 1999;248:143). So are we really implanting what we think we are? Aim of the presented study is to investigate the stem cell concentration and delivery obtained after biomaterial perfusion with bone marrow aspirate. STUDY DESIGN/SETTING: In vitro study. PATIENT SAMPLE: Samples from 3 different patients were used and 9 biomaterials of each type were prepared per bone marrow aspirate. HETCAM experiments were performed in triplicates. OUTCOME MEASURES: Cell seeding density within the biomaterial and angionenesis after in vivo transplantation were assessed using histomorphometrycal methods. METHODS: Surplus material remaining after cage and intervertebral space preparation for routine spinal fusion surgery was analyzed. Three different biomaterials (demineralised bone matrix - DBX, ChronOSÒ and HealOSÒ were impregnated according to specifications of the supplyer. The cell seeded biomaterials were fixed in 4% paraformaldehyde and processed for histological analysis. Stem cell density was assessed after H/E and May Gruenwald staining using an Olympus IX-71 microscope and cellF analysis software. To investgate in vivo effects, cell seeded biomaterials were tranplanted onto the chick chorionallantoic membrane model and biomaterial integration, cell distribution and angiogenesis were evaluated. RESULTS: Most of the cells in bone marrow aspirate were identified as erythrocytes while only a small fraction was identified as nucleated stem cells. After biomaterial impregnation, average stem cell density was 1,13 cells/mm2 (ChronOSÒ), 0.92 cells/mm2 (HealOSÒ) and 0.008 cells/ mm2 (DBX). Only the marginal pores of the biomaterials were filled with cells (mostly erythrocytes) after biomaterial implantation. Despite the poor cell yield, the cell impregnated biomaterials were able to stimulate angiogenesis in the CAM-Model. CONCLUSIONS: Impregnation of biomaterials with bone marrow aspirate can only deliver very small amounts of osteoprogenitor cells to the implantation site. Although these constructs are able to stimulate angiogenesis, the number of osteoprogenotor cells delivered seems to small to have a significant effect on osteogenesis. Increasing cell density by centrifugation or expansion in culture might therefore be required to improve fusion results. FDA DEVICE/DRUG STATUS: Demineralized bone matrix: Approved for this indication; ChronOS: Approved for this indication; HealOS: Approved for this indication. doi: 10.1016/j.spinee.2011.08.154
doi: 10.1016/j.spinee.2011.08.155
119. Recombinant Human Bone Morphogenetic Protein-2 (rhBMP-2) in Posterolateral Lumbar Spine Fusion: Complications in the Elderly Martin Hoffmann, MD, Clifford B. Jones, MD; Grand Rapids, MI, USA BACKGROUND CONTEXT: rhBMP-2 (INFUSE) has been utilized off label for instrumented lumbar posterolateral fusions for many
All referenced figures and tables will be available at the Annual Meeting and will be included with the post-meeting online content.