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169. Biomechanical analysis of motion following lateral sacroiliac joint screw fixation with or without lumbosacral fixation
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Proceedings of the 34th Annual Meeting of the North American Spine Society / The Spine Journal 19 (2019) S59−S100
in PT groups at 2 weeks compared to SHAM and observed to a lesser extent at week 4. CONCLUSIONS: This study demonstrates: (i) sustained cell viability post electroporation of IVD cells, (ii) high expression of T maintained over 4 weeks, and (iii) potential of T to reprogram degenerate human NP cells to a healthy phenotype (up regulation of T and KRT19) with down regulation of inflammatory (IL-1B, 1L6), pain (NGF), and catabolic (MMP12) markers on the gene level with increase matrix synthesis at the protein level (GAG). This is the first study to demonstrate successful reprogramming of diseased human NP cells into a healthy phenotype using nonviral transfection and is a potential therapy to LBP. Future work will use novel electroporation technique, tissue nanotransfection, which has shown to reprogram and rescue diseased tissue. This allows for high efficiency delivery of factors into patient cells while bypassing caveats of viral methods to stimulate IVD repair FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs.
Thursday, September 26, 2019 2:05 − 3:05 PM Cervical Spine Surgery IV 170. In which cases do surgeons specializing in total disc replacement perform fusion in patients with cervical spine symptoms? Richard D. Guyer, MD1, Donna D. Ohnmeiss, PhD2, Scott L. Blumenthal, MD3, Jack E. Zigler, MD3; 1 Center for Disc Replacement at Texas Back Institute, Plano, TX, USA; 2 Plano, TX, US; 3 Texas Back Institute, Plano, TX, USA
BACKGROUND CONTEXT: Hypermobility or aberrant mechanics of the sacroiliac joint (SIJ) can be a source of pain. Lumbosacral fixation at L5−S1 may also be a source of postfusion low back pain. Prior biomechanical research has shown that fusion at the lumbar spine level can increase motion and stresses at the sacroiliac joint. However, no biomechanical studies have evaluated the effects of sacroiliac joint fixation on sacroiliac joint range of motion (ROM) in the setting of various ligamentous injuries or adjacent level lumbosacral screw and rod fixation. PURPOSE: To assess the ROM of the SIJ after simulated adjacent lumbosacral fixation, with or without SIJ fixation, with lateral sacroiliac screws. STUDY DESIGN/SETTING: In vitro biomechanical study. METHODS: In this in vitro biomechanical study, 7 cadaveric specimens (L3−P) were tested on a six-degrees-of-freedom machine under load control at 1.5˚/s to a maximum moment of §8.5 Nm. The ligaments at the left posterior sacroiliac joints were destroyed to maximize ROM of the joint. The influence of lumbosacral fixation on SIJ motion, with or without SIJ fixation, was studied. RESULTS: During flexion-extension in the setting of posterior SIJ injury and L5−S1 fixation, SIJ ROM increased to 195% of intact. After SIJ fixation with lateral sacroiliac screws, the average ROM was reduced to 144% of intact SIJ motion. SIJ screws thus partially stabilized the joint and reduced motion. The use of 6 bilateral SIJ screws with L5−S1 screw and rod fixation in lateral bending and axial rotation yielded the greatest reduction in SIJ ROM. Without lumbosacral fixation, baseline SIJ motion was reduced, and SIJ screws alone, using either 2, 3, or 6 screws, reduced motion at or below the level of an intact joint. CONCLUSIONS: SIJ ligament injury with existing lumbosacral fixation doubled SIJ ROM. After SIJ fixation with lateral sacroiliac screws, ROM decreased. Screw configuration played a minor role; however, 6 SIJ screws generally had the greatest motion reduction. FDA DEVICE/DRUG STATUS: SI-LOK screws (Approved for this indication).
BACKGROUND CONTEXT: Results of cervical total disc replacement (TDR) have consistently been reported to be similar or superior to anterior cervical discectomy and fusion (ACDF) in appropriately selected patients. PURPOSE: The purpose of this study was to investigate the reasons and their frequency for why TDR specialty surgeons performed ACDF rather than TDR. STUDY DESIGN/SETTING: The study was based on a retrospective record review. PATIENT SAMPLE: The study was based on a consecutive series of 464 patients undergoing cervical spine surgery during a 5-year period by three surgeons specializing in TDR. OUTCOME MEASURES: The primary outcome measure was the reason to perform ACDF rather than TDR. METHODS: For each ACDF, the reason for not performing TDR (including hybrids) was recorded. After recording a description of the primary reason for performing ACDF, these were classified into categories such as anatomical, kyphosis/scoliosis, insurance (denial, Medicare), etc. The anatomical category included excessive spondylosis which, when corrected, would likely compromise implant stability, facet arthropathy, severe neuroforaminal stenosis that could not be adequately decompressed and structural integrity to support TDR maintained, and severe spondylosis with little or no segmental motion that would significantly limit TDR movement. RESULTS: During the study period, 76.7% of the patients (n=356) underwent TDR and the remaining 23.3% (n=108) underwent ACDF. Based on the population of 464 patients, the most common reason for ACDF vs TDR was anatomical, which occurred in 64 patients (13.79%). The second most common reason was insurance (n=17, 3.23%) and deformity/kyphosis not addressable with TDR was noted in 13 patients (2.80%). Pseudoarthrosis repair led to ACDF in 3 patients (0.65%); two did not receive TDR due to osteoporosis (0.43%) and in two others (0.43%), ACDF was undertaken due to high risk of heterotopic ossification. There was one case (0.22%) each of: nickel allergy, trauma with posterior element fracture, TDR removal, multiple prior cervical spine surgeries, concern about artifact on future imaging studies, benign osteoblastic bone, and limitation to an adequate surgical approach for TDR implantation. ACDF patients’ mean age was significantly greater than TDR patients (55.3 vs 46.7 years; p<0.01). There was no significant difference between the two groups with respect to gender (both approximately 40% female). The TDR group had significantly more single-level procedures than the ACDF group (60.8% vs 43.5%; p<0.05). CONCLUSIONS: The most common reason for not performing cervical TDR was related to factors that may compromise the stability of the operated segment and/or functionality of the TDR. The older age and greater number of operated levels may be related to the anatomical factors leading to ACDF − primarily significant osteophytes and severely degenerated facet joints. These factors as well as cervical deformity/kyphosis are more likely to occur in older patients and require multi-level treatment to address. The results of this study found that many patients are good candidates for cervical TDR. However, even among TDR specialists, ACDF may be preferred in some patients where it is prudent to not take undue risks. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs.
https://doi.org/10.1016/j.spinee.2019.05.186
https://doi.org/10.1016/j.spinee.2019.05.187
https://doi.org/10.1016/j.spinee.2019.05.185
169. Biomechanical analysis of motion following lateral sacroiliac joint screw fixation with or without lumbosacral fixation Bruce E. Dall, MD1, Sonia V. Eden, MD2, Woojin Cho, MD, PhD3, Alexa Karkenny, MD3, Gerald Hayward, BS4, Daina M. Brooks, BS5, Mark Moldavsky, MS6, Soumya Yandamuri, PhD, MS4, Brandon Bucklen, PhD4; 1 Western Michigan University Homer Stryker School of Medicine, Kalamazoo, MI, US; 2 Borgess Medical Center/ Neurosurgery of Kalamazoo, Kalamazoo, MI, US; 3 Bronx, NY, US; 4 Globus Medical, Inc., Audubon, PA, US; 5 Medstar Union Memorial Hospital, Baltimore, MD, US; 6 Villanova, PA, US
Refer to onsite annual meeting presentations and postmeeting proceedings for possible referenced figures and tables. Authors are responsible for accurately reporting disclosure and FDA device/drug status at time of abstract submission.
Proceedings of the 34th Annual Meeting of the North American Spine Society / The Spine Journal 19 (2019) S59−S100
in PT groups at 2 weeks compared to SHAM and observed to a lesser extent at week 4. CONCLUSIONS: This study demonstrates: (i) sustained cell viability post electroporation of IVD cells, (ii) high expression of T maintained over 4 weeks, and (iii) potential of T to reprogram degenerate human NP cells to a healthy phenotype (up regulation of T and KRT19) with down regulation of inflammatory (IL-1B, 1L6), pain (NGF), and catabolic (MMP12) markers on the gene level with increase matrix synthesis at the protein level (GAG). This is the first study to demonstrate successful reprogramming of diseased human NP cells into a healthy phenotype using nonviral transfection and is a potential therapy to LBP. Future work will use novel electroporation technique, tissue nanotransfection, which has shown to reprogram and rescue diseased tissue. This allows for high efficiency delivery of factors into patient cells while bypassing caveats of viral methods to stimulate IVD repair FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs.
Thursday, September 26, 2019 2:05 − 3:05 PM Cervical Spine Surgery IV 170. In which cases do surgeons specializing in total disc replacement perform fusion in patients with cervical spine symptoms? Richard D. Guyer, MD1, Donna D. Ohnmeiss, PhD2, Scott L. Blumenthal, MD3, Jack E. Zigler, MD3; 1 Center for Disc Replacement at Texas Back Institute, Plano, TX, USA; 2 Plano, TX, US; 3 Texas Back Institute, Plano, TX, USA
BACKGROUND CONTEXT: Hypermobility or aberrant mechanics of the sacroiliac joint (SIJ) can be a source of pain. Lumbosacral fixation at L5−S1 may also be a source of postfusion low back pain. Prior biomechanical research has shown that fusion at the lumbar spine level can increase motion and stresses at the sacroiliac joint. However, no biomechanical studies have evaluated the effects of sacroiliac joint fixation on sacroiliac joint range of motion (ROM) in the setting of various ligamentous injuries or adjacent level lumbosacral screw and rod fixation. PURPOSE: To assess the ROM of the SIJ after simulated adjacent lumbosacral fixation, with or without SIJ fixation, with lateral sacroiliac screws. STUDY DESIGN/SETTING: In vitro biomechanical study. METHODS: In this in vitro biomechanical study, 7 cadaveric specimens (L3−P) were tested on a six-degrees-of-freedom machine under load control at 1.5˚/s to a maximum moment of §8.5 Nm. The ligaments at the left posterior sacroiliac joints were destroyed to maximize ROM of the joint. The influence of lumbosacral fixation on SIJ motion, with or without SIJ fixation, was studied. RESULTS: During flexion-extension in the setting of posterior SIJ injury and L5−S1 fixation, SIJ ROM increased to 195% of intact. After SIJ fixation with lateral sacroiliac screws, the average ROM was reduced to 144% of intact SIJ motion. SIJ screws thus partially stabilized the joint and reduced motion. The use of 6 bilateral SIJ screws with L5−S1 screw and rod fixation in lateral bending and axial rotation yielded the greatest reduction in SIJ ROM. Without lumbosacral fixation, baseline SIJ motion was reduced, and SIJ screws alone, using either 2, 3, or 6 screws, reduced motion at or below the level of an intact joint. CONCLUSIONS: SIJ ligament injury with existing lumbosacral fixation doubled SIJ ROM. After SIJ fixation with lateral sacroiliac screws, ROM decreased. Screw configuration played a minor role; however, 6 SIJ screws generally had the greatest motion reduction. FDA DEVICE/DRUG STATUS: SI-LOK screws (Approved for this indication).
BACKGROUND CONTEXT: Results of cervical total disc replacement (TDR) have consistently been reported to be similar or superior to anterior cervical discectomy and fusion (ACDF) in appropriately selected patients. PURPOSE: The purpose of this study was to investigate the reasons and their frequency for why TDR specialty surgeons performed ACDF rather than TDR. STUDY DESIGN/SETTING: The study was based on a retrospective record review. PATIENT SAMPLE: The study was based on a consecutive series of 464 patients undergoing cervical spine surgery during a 5-year period by three surgeons specializing in TDR. OUTCOME MEASURES: The primary outcome measure was the reason to perform ACDF rather than TDR. METHODS: For each ACDF, the reason for not performing TDR (including hybrids) was recorded. After recording a description of the primary reason for performing ACDF, these were classified into categories such as anatomical, kyphosis/scoliosis, insurance (denial, Medicare), etc. The anatomical category included excessive spondylosis which, when corrected, would likely compromise implant stability, facet arthropathy, severe neuroforaminal stenosis that could not be adequately decompressed and structural integrity to support TDR maintained, and severe spondylosis with little or no segmental motion that would significantly limit TDR movement. RESULTS: During the study period, 76.7% of the patients (n=356) underwent TDR and the remaining 23.3% (n=108) underwent ACDF. Based on the population of 464 patients, the most common reason for ACDF vs TDR was anatomical, which occurred in 64 patients (13.79%). The second most common reason was insurance (n=17, 3.23%) and deformity/kyphosis not addressable with TDR was noted in 13 patients (2.80%). Pseudoarthrosis repair led to ACDF in 3 patients (0.65%); two did not receive TDR due to osteoporosis (0.43%) and in two others (0.43%), ACDF was undertaken due to high risk of heterotopic ossification. There was one case (0.22%) each of: nickel allergy, trauma with posterior element fracture, TDR removal, multiple prior cervical spine surgeries, concern about artifact on future imaging studies, benign osteoblastic bone, and limitation to an adequate surgical approach for TDR implantation. ACDF patients’ mean age was significantly greater than TDR patients (55.3 vs 46.7 years; p<0.01). There was no significant difference between the two groups with respect to gender (both approximately 40% female). The TDR group had significantly more single-level procedures than the ACDF group (60.8% vs 43.5%; p<0.05). CONCLUSIONS: The most common reason for not performing cervical TDR was related to factors that may compromise the stability of the operated segment and/or functionality of the TDR. The older age and greater number of operated levels may be related to the anatomical factors leading to ACDF − primarily significant osteophytes and severely degenerated facet joints. These factors as well as cervical deformity/kyphosis are more likely to occur in older patients and require multi-level treatment to address. The results of this study found that many patients are good candidates for cervical TDR. However, even among TDR specialists, ACDF may be preferred in some patients where it is prudent to not take undue risks. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs.
https://doi.org/10.1016/j.spinee.2019.05.186
https://doi.org/10.1016/j.spinee.2019.05.187
https://doi.org/10.1016/j.spinee.2019.05.185
169. Biomechanical analysis of motion following lateral sacroiliac joint screw fixation with or without lumbosacral fixation Bruce E. Dall, MD1, Sonia V. Eden, MD2, Woojin Cho, MD, PhD3, Alexa Karkenny, MD3, Gerald Hayward, BS4, Daina M. Brooks, BS5, Mark Moldavsky, MS6, Soumya Yandamuri, PhD, MS4, Brandon Bucklen, PhD4; 1 Western Michigan University Homer Stryker School of Medicine, Kalamazoo, MI, US; 2 Borgess Medical Center/ Neurosurgery of Kalamazoo, Kalamazoo, MI, US; 3 Bronx, NY, US; 4 Globus Medical, Inc., Audubon, PA, US; 5 Medstar Union Memorial Hospital, Baltimore, MD, US; 6 Villanova, PA, US
Refer to onsite annual meeting presentations and postmeeting proceedings for possible referenced figures and tables. Authors are responsible for accurately reporting disclosure and FDA device/drug status at time of abstract submission.