- Email: [email protected]
3. Fatigue analysis of multilevel anterior cervical fusion with stand-alone anchored spacer vs interbody cage with anterior plate
S2
Proceedings of the 34th Annual Meeting of the North American Spine Society / The Spine Journal 19 (2019) S1−S58
longitudinal cut to analyze internal cellular migration patterns. Cell viability determined by LIVE/DEAD assay was performed on a separate scaffold. The biological response was investigated on two separate scaffolds per group by cell lysate and media assays for alkaline phosphatase, DNA content, osteocalcin, BMP2, osteoprotegerin, and vascular endothelial growth factor (VEGF) quantification per manufacturer’s instructions. RESULTS: ESEM imaging analysis of each scaffold surface demonstrated that hMSCs had the strongest adhesive affinity for surfaces with porosities between 50% and 70%. Scaffolds within this range, when sliced longitudinally, demonstrated a more robust and dense internal cellular migration pattern than those outside the range. High cell viability on implant surface confirmed biological response by LIVE/DEAD assay. Conditioned media assay revealed increased levels of BMP2 expression on porosities between 50-70% with increased levels of VEGF, osteocalcin, and osteoprotegerin expression on scaffolds with porosities between 70-80%. Lower porosities scaffolds demonstrated increased levels of DNA and alkaline phosphatase activity. CONCLUSIONS: Osseointegration requires complex biological conditions and our findings suggest that cellular optimization occurs with an approximate porosity of 60% (range: 50-70%). Made possible by the advancing field of 3D printing technology, precision surface engineering plays a determinant role in cellular adhesion and functioning, leading to enhanced osseointegrative potential. FDA DEVICE/DRUG STATUS: Unavailable from authors at time of publication. https://doi.org/10.1016/j.spinee.2019.05.015
3. Fatigue analysis of multilevel anterior cervical fusion with standalone anchored spacer vs interbody cage with anterior plate Aymen Rashid, MD1, Nathaniel R. Ordway, MS2, James B. Allen3, Satyajit Marawar, MD4, William F. Lavelle, MD5; 1 SUNY Upstate University Hospital, Syracuse, NY, US; 2 SUNY Upstate Medical University, Syracuse, NY, US; 3 Syracuse, NY, US; 4 Syracuse VAHCN, Syracuse, NY, US; 5 Upstate Orthopedics, East Syracuse, NY, US BACKGROUND CONTEXT: Anterior cervical discectomy and fusion (ACDF) is the surgical standard for treating anterior based cervical spine pathology with interbody spacers and plating most common. Complications are more prevalent in multilevel cases. Stand-alone anchored spacers were designed to resolve these issues. For 1-level ACDF they provide similar clinical results, fewer implant related complications and decreased compensatory motion at adjacent levels. Reporting on fatigue analysis of multilevel plating vs anchored spacers is limited. PURPOSE: Perform fatigue analysis and compare spinal stability of 3level cervical ACDF constructs using either anchored spacers or standard cages with anterior plating. STUDY DESIGN/SETTING: In-vitro biomechanical study. OUTCOME MEASURES: Range of motion (ROM) of index levels, adjacent segments, and overall construct. METHODS: Spinal stability testing was performed on cadaveric cervical spines (C2-T2) in sagittal, coronal and transverse planes. Specimens tested intact and assigned to either anchored spacer or anterior plate group. Each had a 3-level discectomy (C4/5, C5/6, and C6/7), followed by assigned instrumentation. Specimens retested followed by a fatigue protocol of 5k cycles of flexion/extension and then 5k cycles of axial rotation. Spinal stability testing was performed following each 5k cycles of fatigue. ROM was measured from the index levels, adjacent segments, and overall construct. Peak directional ROMs were compared between groups and analyzed with ANOVA and post hoc t-tests. RESULTS: There were similar and significant (p<0.05) reductions in overall construct ROM and index level ROM for both groups following ACDF. In flexion/extension, the plate group had 0.5˚ for index ROM, adjacent segments had 3.4˚ and 2.4˚ of motion; the anchored spacer group had 2.4˚ for index ROM, adjacent segments had 3.1˚ and 1.9˚. Following fatigue, flexion/extension ROM in the index and adjacent segments
increased significantly with more ROM in the anchored spacer compared to the anterior plate group. In lateral bending, index ROM for the anterior plate group was 0.9˚ and adjacent segment motion was 1.8˚ and 2.1˚; index ROM for the anchored spacer group was 1.1˚ and adjacent segment motion was 3.1˚ and 3.2˚. After fatigue, lateral bending ROM of the index levels was not significant, but significant increases in ROM of adjacent segments occurred. In lateral bending, no significant differences were seen between groups pre- and post-fatigue. CONCLUSIONS: For 3-level ACDF, there was a significant increase in ROM in the index levels using anchored spacers with no significant change in adjacent segment ROM when compared to standard cages and anterior plate. After fatigue, an increase in index ROM and adjacent segment ROM was seen with the anchored spacer compared to anterior plating. Future studies are needed to determine if differences in motion have any clinical significance regarding fusion in 3-level ACDF. FDA DEVICE/DRUG STATUS: Stand-alone anchored spacer (Approved for this indication), interbody cage with anterior place (Approved for this indication) https://doi.org/10.1016/j.spinee.2019.05.016 4. Lumbosacral TLIF but not ALIF increases proximal junction motion in long-segment constructs Randall J. Hlubek, MD1, Jakub Godzik, MD2, Anna G. Newcomb, MS3, Jennifer Lehrman, MS1, Bernardo De Andrada Pereira, MD2, Brian Kelly, PhD1, Jay D. Turner, MD, PhD4; 1 Barrow Neurological Institute, Phoenix, AZ, US; 2 Phoenix, AZ, US; 3 St. Joseph’s Hospital and Medical Center, Phoenix, AZ, US; 4 Barrow Brain and Spine, Phoenix, AZ, US BACKGROUND CONTEXT: Proximal junctional kyphosis and lumbosacral (LS) pseudoarthrosis/instrumentation failure are relatively common complications following long instrumentation constructs to the sacrum. Methods to improve fusion rates and decrease instrumentation failure include LS anterior column support (ALIF or TLIF), iliac screw fixation, and accessory rods. The impact of these lumbosacral augmentation strategies on the proximal junction is not clear. PURPOSE: The purpose of this study was to investigate the impact of various lumbosacral constructs on proximal junction biomechanics. STUDY DESIGN/SETTING: Human biomechanical cadaveric study. PATIENT SAMPLE: Twelve (L1-Pelvis) cadaveric spines were studied. OUTCOME MEASURES: Proximal junction range of motion (ROM) at L1-2 was measured. METHODS: Fourteen human cadaveric spine (L1-Ilium) specimens were prepared and potted at L1 and Ilium. Specimens were equally divided into either an L5-S1 ALIF or TLIF group. 4R conditions consisted of accessory rods spanning the L3-L4 and S1-Ilium levels. Compression (400 N) in combination with 7.5 Nm of flexion (FL), extension (EX), lateral bending (LB), or axial rotation (AR) was applied to all conditions. Specimens underwent testing in the following conditions: (1) intact, (2) L2-S1 pedicle screw fixation (PSR), (3) L2-ilium (PSR-I), (4) PSR+ALIF (ALIF-S) or TLIF (TLIF-S), (5) PSR-I + ALIF (ALIF-I) or TLIF (TLIF-I), and (6) ALIF-I + 4R or TLIF-I + 4R. Statistical comparisons were performed using one-way (RM) ANOVA (p<.05). RESULTS: PSR-I did not significantly change proximal junction ROM in any direction compared to PSR-S (p>.069). However, TLIF-I and TLIF +4R resulted in significant increase in L1-2 ROM in FL and Right LB (p<.038) compared To PSR-I. TLIF-I+4R did not change ROM compared to TLIF-I in any direction (p>.095). ALIF-I did not significantly change ROM in any direction compared to ALIF+4R or PSR-I (p>.069). CONCLUSIONS: In cadavers with pelvic fixation, lumbosacral TLIF results in increased ROM at the proximal junction while ALIF does not. Further augmentation of either ALIF or TLIF constructs with lumbosacral accessory rods does not impact proximal junctional ROM. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs. https://doi.org/10.1016/j.spinee.2019.05.017
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) S1−S58
longitudinal cut to analyze internal cellular migration patterns. Cell viability determined by LIVE/DEAD assay was performed on a separate scaffold. The biological response was investigated on two separate scaffolds per group by cell lysate and media assays for alkaline phosphatase, DNA content, osteocalcin, BMP2, osteoprotegerin, and vascular endothelial growth factor (VEGF) quantification per manufacturer’s instructions. RESULTS: ESEM imaging analysis of each scaffold surface demonstrated that hMSCs had the strongest adhesive affinity for surfaces with porosities between 50% and 70%. Scaffolds within this range, when sliced longitudinally, demonstrated a more robust and dense internal cellular migration pattern than those outside the range. High cell viability on implant surface confirmed biological response by LIVE/DEAD assay. Conditioned media assay revealed increased levels of BMP2 expression on porosities between 50-70% with increased levels of VEGF, osteocalcin, and osteoprotegerin expression on scaffolds with porosities between 70-80%. Lower porosities scaffolds demonstrated increased levels of DNA and alkaline phosphatase activity. CONCLUSIONS: Osseointegration requires complex biological conditions and our findings suggest that cellular optimization occurs with an approximate porosity of 60% (range: 50-70%). Made possible by the advancing field of 3D printing technology, precision surface engineering plays a determinant role in cellular adhesion and functioning, leading to enhanced osseointegrative potential. FDA DEVICE/DRUG STATUS: Unavailable from authors at time of publication. https://doi.org/10.1016/j.spinee.2019.05.015
3. Fatigue analysis of multilevel anterior cervical fusion with standalone anchored spacer vs interbody cage with anterior plate Aymen Rashid, MD1, Nathaniel R. Ordway, MS2, James B. Allen3, Satyajit Marawar, MD4, William F. Lavelle, MD5; 1 SUNY Upstate University Hospital, Syracuse, NY, US; 2 SUNY Upstate Medical University, Syracuse, NY, US; 3 Syracuse, NY, US; 4 Syracuse VAHCN, Syracuse, NY, US; 5 Upstate Orthopedics, East Syracuse, NY, US BACKGROUND CONTEXT: Anterior cervical discectomy and fusion (ACDF) is the surgical standard for treating anterior based cervical spine pathology with interbody spacers and plating most common. Complications are more prevalent in multilevel cases. Stand-alone anchored spacers were designed to resolve these issues. For 1-level ACDF they provide similar clinical results, fewer implant related complications and decreased compensatory motion at adjacent levels. Reporting on fatigue analysis of multilevel plating vs anchored spacers is limited. PURPOSE: Perform fatigue analysis and compare spinal stability of 3level cervical ACDF constructs using either anchored spacers or standard cages with anterior plating. STUDY DESIGN/SETTING: In-vitro biomechanical study. OUTCOME MEASURES: Range of motion (ROM) of index levels, adjacent segments, and overall construct. METHODS: Spinal stability testing was performed on cadaveric cervical spines (C2-T2) in sagittal, coronal and transverse planes. Specimens tested intact and assigned to either anchored spacer or anterior plate group. Each had a 3-level discectomy (C4/5, C5/6, and C6/7), followed by assigned instrumentation. Specimens retested followed by a fatigue protocol of 5k cycles of flexion/extension and then 5k cycles of axial rotation. Spinal stability testing was performed following each 5k cycles of fatigue. ROM was measured from the index levels, adjacent segments, and overall construct. Peak directional ROMs were compared between groups and analyzed with ANOVA and post hoc t-tests. RESULTS: There were similar and significant (p<0.05) reductions in overall construct ROM and index level ROM for both groups following ACDF. In flexion/extension, the plate group had 0.5˚ for index ROM, adjacent segments had 3.4˚ and 2.4˚ of motion; the anchored spacer group had 2.4˚ for index ROM, adjacent segments had 3.1˚ and 1.9˚. Following fatigue, flexion/extension ROM in the index and adjacent segments
increased significantly with more ROM in the anchored spacer compared to the anterior plate group. In lateral bending, index ROM for the anterior plate group was 0.9˚ and adjacent segment motion was 1.8˚ and 2.1˚; index ROM for the anchored spacer group was 1.1˚ and adjacent segment motion was 3.1˚ and 3.2˚. After fatigue, lateral bending ROM of the index levels was not significant, but significant increases in ROM of adjacent segments occurred. In lateral bending, no significant differences were seen between groups pre- and post-fatigue. CONCLUSIONS: For 3-level ACDF, there was a significant increase in ROM in the index levels using anchored spacers with no significant change in adjacent segment ROM when compared to standard cages and anterior plate. After fatigue, an increase in index ROM and adjacent segment ROM was seen with the anchored spacer compared to anterior plating. Future studies are needed to determine if differences in motion have any clinical significance regarding fusion in 3-level ACDF. FDA DEVICE/DRUG STATUS: Stand-alone anchored spacer (Approved for this indication), interbody cage with anterior place (Approved for this indication) https://doi.org/10.1016/j.spinee.2019.05.016 4. Lumbosacral TLIF but not ALIF increases proximal junction motion in long-segment constructs Randall J. Hlubek, MD1, Jakub Godzik, MD2, Anna G. Newcomb, MS3, Jennifer Lehrman, MS1, Bernardo De Andrada Pereira, MD2, Brian Kelly, PhD1, Jay D. Turner, MD, PhD4; 1 Barrow Neurological Institute, Phoenix, AZ, US; 2 Phoenix, AZ, US; 3 St. Joseph’s Hospital and Medical Center, Phoenix, AZ, US; 4 Barrow Brain and Spine, Phoenix, AZ, US BACKGROUND CONTEXT: Proximal junctional kyphosis and lumbosacral (LS) pseudoarthrosis/instrumentation failure are relatively common complications following long instrumentation constructs to the sacrum. Methods to improve fusion rates and decrease instrumentation failure include LS anterior column support (ALIF or TLIF), iliac screw fixation, and accessory rods. The impact of these lumbosacral augmentation strategies on the proximal junction is not clear. PURPOSE: The purpose of this study was to investigate the impact of various lumbosacral constructs on proximal junction biomechanics. STUDY DESIGN/SETTING: Human biomechanical cadaveric study. PATIENT SAMPLE: Twelve (L1-Pelvis) cadaveric spines were studied. OUTCOME MEASURES: Proximal junction range of motion (ROM) at L1-2 was measured. METHODS: Fourteen human cadaveric spine (L1-Ilium) specimens were prepared and potted at L1 and Ilium. Specimens were equally divided into either an L5-S1 ALIF or TLIF group. 4R conditions consisted of accessory rods spanning the L3-L4 and S1-Ilium levels. Compression (400 N) in combination with 7.5 Nm of flexion (FL), extension (EX), lateral bending (LB), or axial rotation (AR) was applied to all conditions. Specimens underwent testing in the following conditions: (1) intact, (2) L2-S1 pedicle screw fixation (PSR), (3) L2-ilium (PSR-I), (4) PSR+ALIF (ALIF-S) or TLIF (TLIF-S), (5) PSR-I + ALIF (ALIF-I) or TLIF (TLIF-I), and (6) ALIF-I + 4R or TLIF-I + 4R. Statistical comparisons were performed using one-way (RM) ANOVA (p<.05). RESULTS: PSR-I did not significantly change proximal junction ROM in any direction compared to PSR-S (p>.069). However, TLIF-I and TLIF +4R resulted in significant increase in L1-2 ROM in FL and Right LB (p<.038) compared To PSR-I. TLIF-I+4R did not change ROM compared to TLIF-I in any direction (p>.095). ALIF-I did not significantly change ROM in any direction compared to ALIF+4R or PSR-I (p>.069). CONCLUSIONS: In cadavers with pelvic fixation, lumbosacral TLIF results in increased ROM at the proximal junction while ALIF does not. Further augmentation of either ALIF or TLIF constructs with lumbosacral accessory rods does not impact proximal junctional ROM. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs. https://doi.org/10.1016/j.spinee.2019.05.017
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.