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Reliability and Validity of the Thoracolumbar Injury Classification System in Pediatric Spine Trauma
Proceedings of the NASS 29th Annual Meeting / The Spine Journal 14 (2014) 1S–183S
155S
PATIENT SAMPLE: From June 2010 to October 2012, 49 patients underwent navigated MIS SI joint fusions by a single surgeon. One was lost to follow-up and excluded. OUTCOME MEASURES: Oswestry Disability Index (ODI) and Visual Analog Scale (VAS) scores. METHODS: A consecutive case series of patients were reviewed. Statistical comparisons on Oswestry Disability Index (ODI) and Visual Analog Scale (VAS) scores explored differences in patients with or without a prior history of lower back surgery. RESULTS: Patients’ average age was 48 years (range 18-77), with 13 males and 35 females. 62.5% (30/48) had a history of back or hip surgery, while 37.5% (18/48) had isolated SI joint disease. 56% (27/48) were unilateral and 44% (21/48) were bilateral. Revision rate was 8% (4/48) with 2 unilateral and 2 bilateral MIS revisions. Among bilateral procedures, there were 3 simultaneous, 4 contralateral sides by other surgeons, and 1 revision by another surgeon. Average time to contralateral SI joint fusion was 6 months (range 1-12). Mean change in ODI and VAS scores did not differ significantly by surgical history (ODID 11619 vs 9613; VASD 2.562.4 vs 1.362.2; pO0.05), although scores tended to be better in patients with isolated SI joint disease. CONCLUSIONS: More patients undergoing MIS SI joint fusions have a history of lumbar or hip surgery, which likely affects patient outcomes scores, especially ODI. Both VAS and ODI scores at final follow-up tended to be better in patients with isolated SI joint disease. However, the ODI and VAS may not be adequate measurement for patients with bilateral SI joint disease, or concomitant lumbar and/or hip disease undergoing unilateral SI joint fusion. When considering SI joint fusion, a history of lumbar surgery or disease can be a factor in outcomes. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs.
VEGF expression at 3, 7 and 14 days was significantly higher than that at 24 hours. The majority of neural cells demonstrated hypoxia accompanied with brown HIF-1a positive staining in the local injured cord segment. A profoundly hypoxemic metabolism condition at 1 and 3 day postinjury is suggested due to the peak counts of positive HIF-1a cells rate. CONCLUSIONS: 1. Trauma directly causes structural and volumetric damage to the microvasculature in the rat SCI model. 2. The injured spinal cord was trapped in serious hypoxia due to the local microcirculatory disorder during the acute SCI process. 3. Post-traumatic angiogenesis probably served as an inherent mechanism to promote the vascular remodeling, which was closely correlated with the hypoxia regulatory mechanism. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs.
http://dx.doi.org/10.1016/j.spinee.2014.08.374
BACKGROUND CONTEXT: The thoracolumbar injury classification system (TLICS) was developed to improve the categorization and management of thoracolumbar trauma. TLICS has been shown to have good reliability and validity in the adult population. PURPOSE: The purpose of this study was to determine the clinical applicability of the TLICS in pediatric spine trauma. STUDY DESIGN/SETTING: TLICS was prospectively evaluated using 20 nonconsecutive pediatric spine trauma case examples. PATIENT SAMPLE: 20 cases of pediatric spine trauma. OUTCOME MEASURES: Reliability and validity (Kappa coefficient). METHODS: The clinical and radiographic findings of 20 pediatric thoracolumbar fractures were prospectively presented to 20 surgeons with varying levels of training and experience with spinal trauma. These injuries were consecutively scored using the TLICS. Cohen’s unweighted kappa coefficients and Spearman’s rank order correlation values were calculated for the key parameters (injury morphology, status of PLC, neurological status, and proposed management) to assess the inter-rater reliabilities. Five surgeons scored the same cases 2 months later to assess the intra-rater reliability. The actual management of each case was then compared with the treatment recommended by the TLICS algorithm to assess validity. RESULTS: The inter-rater kappa statistics of all subgroups (injury morphology, status of the posterior ligamentous complex, neurological status, and proposed treatment) were within the range of moderate to substantial reproducibility (0.449-0.958). Proposed treatment had the lowest interrater agreement (0.449). All subgroups had excellent intra-rater reliability (0.748-1.000). The various indices for validity were calculated (80.3% correct, 0.836 sensitivity, 0.785 specificity, 0.676 positive predictive value, 0.899 negative predictive value). CONCLUSIONS: The thoracolumbar injury classification system has good reliability and validity when used in the pediatric population. The inter-rater reliability of predicting management and indices for validity are lower than in adults with thoracolumbar fractures, which is likely due to differences in the way children are treated for certain types of injuries. TLICS can be used to reliably categorize thoracolumbar injuries in the pediatric population; however, modifications may be needed to better guide treatment in this specific patient population.
P121. Post-traumatic Angiogenesis Correlated with Hypoxia Regulation after Acute Spinal Cord Injury in Rat Hongbin Lu, MD, PhD; Changsha, China PURPOSE: To investigate the post-traumatic angiogenesis and correlated regulatory mechanism in a rat model of acute spinal cord injury (SCI). METHODS: 1. Rat SCI Modeling and Groups: 64 SD rats were subjected to the modified Allen’s weight impacting to induce an incomplete SCI model. The other 16 rats only underwent laminotomy to serve as a sham group. The T10 cord samples were harvested at 1, 3, 7 and 14 day postinjury (n54, respectively). 2. Micro-CT Detection and Thick Tissue Section: the samples with angiography underwent micro-CT imaging for 3D vascular rendering, followed by thick section for microscopy observation. The quantitative parameters including vascular volume fraction (VVF), thickness, separation and connectivity were analyzed by microview software package. 3. Immunofluorescent Staining: the RECA-1 antibody was used to label the endothelial cells for microvessel staining, and DAPI for cell nucleus, and the VEGF proteins were labeled to green. The integrated optical density (IOD) was calculated to evaluate the VEGF expression, and the vessel with RECA-1 positive staining was counted by IPP software. 4. Immunohistochemical Staining: the brown cells were counted and identified as positive HIF-1a staining. 5. Western Blot: the pro-angiogenesis correlated factors, including HIF-1a, PGC-1a, ERR-a and VEGF, underwent WB electrophoresis to analyze the semi-quantitative expression level. 6. Statistical analysis was carried out with SPSS 13.0 software, P＜0.05 was interpreted as significant. RESULTS: The distribution of RECA-1 and VEGF positive staining was stated. The microvessel numbers significantly decreased at 24 hours postinjury, and gradually recovered with the healing time implying a post-traumatic angiogenesis. VEGF seemed to be expressed in various neural cells, in which the VEGF positive astrocytes were subsequently activated instead of the degeneration of neurons. The value of integrated optical density of
http://dx.doi.org/10.1016/j.spinee.2014.08.375
P122. Reliability and Validity of the Thoracolumbar Injury Classification System in Pediatric Spine Trauma Jason W. Savage, MD1, Paul M. Arnold, MD2, Wellington K. Hsu, MD3, Alpesh A. Patel, MD, FACS4, Gregory D. Schroeder, MD3, Alexander R. Vaccaro, MD, PhD5, John R. Dimar, II, MD6, Paul A. Anderson, MD7; 1 Chicago, IL, US; 2University of Kansas Medical Center Department of Neurosurgery, Kansas City, KS, US; 3Northwestern University, Chicago, IL, US; 4Northwestern Department of Orthopaedics, Chicago, IL, US; 5 Rothman Institute, Philadelphia, PA, US; 6Spine Institute, Louisville, KY, US; 7University of Wisconsin Orthopedics and Rehabilitation, Madison, WI, US
Refer to onsite Annual Meeting presentations and postmeeting proceedings for possible referenced figures and tables. Authors are responsible for accurately reporting disclosures and FDA device/drug status at time of abstract submission.
156S
Proceedings of the NASS 29th Annual Meeting / The Spine Journal 14 (2014) 1S–183S
FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs.
may be enhanced when PDGF-BB is delivered in a thiol-modified HA hydrogel. FDA DEVICE/DRUG STATUS: PDGF-BB (Investigational/Not approved)
http://dx.doi.org/10.1016/j.spinee.2014.08.376 http://dx.doi.org/10.1016/j.spinee.2014.08.377 P123. Treatment of Injured Intervertebral Discs with PDGF-BB Inhibits Degeneration In Vivo Isaac Moss, MD1, David N. Paglia, PhD2, Hicham Drissi, PhD2; 1Medical Arts and Research Building, Farmington, CT, US; 2University of Connecticut Health Center, Farmington, CT, US BACKGROUND CONTEXT: Back pain is a leading cause of disability in the US. Intervertebral disc (IVD) degeneration is recognized as a major contributing factor to this disorder. Several growth factors have demonstrated the potential to slow or reverse the degenerative processes in vitro and in vivo. Platelet-derived growth factor BB (PDGF-BB), thought to be the primary active component of platelet rich plasma, has been shown to slow the degenerative process, by inhibiting IVD cell apoptosis, and increasing cell proliferation and extracellular matrix (ECM) formation in monolayer and 3-D pellet culture. PURPOSE: The goal of this study was to examine the effect of PDGF-BB in a preclinical model of IVD degeneration. Our hypotheses were that treatment of injured IVDs during midstage disc degeneration would inhibit degeneration; and that these effects could be enhanced when PDGF-BB was administered in combination with a hydrogel capable of gradual release of the growth factor over an extended period. STUDY DESIGN/SETTING: In vivo, preclinical model. PATIENT SAMPLE: New Zealand White Rabbits. OUTCOME MEASURES: MRI, biomechanical testing. METHODS: After institutional animal care committee approval, the welldescribed rabbit annular puncture model of disc degeneration was employed to de-nucleate four lumbar IVDs (L2-3 to L6-7) in New Zealand White Rabbits. Four weeks after the discs were injured (corresponding to mid-stage degeneration), 20 microliters of either: I) sterile saline, II) 1 ng/mL recombinant human PDGF-BB (rhPDGF-BB, Pepro Tech Inc., Rocky Hill, NJ), III) thiol-modified hyaluronic acid (HA, Glycosan, Alameda, CA) hydrogel material, or IV) 1 ng/mL PDGF in the HA hydrogel, were injected into the IVDs from the contralateral side. Rabbits were euthanized at 4 and 8 weeks after intradiscal treatments. Following MRI imaging, the lumbar spines were harvested for histology and biomechanical analyses. MR Images were analyzed to determine the nucleus pulposus area and T2-weighted signal intensity (n512 per group). Uniaxial compressive loading (cyclic strain, creep, and load to failure) was used to determine biomechanical disc integrity and the extent of IVD degeneration (n56 per group). All data were given as means 6 standard deviation of the mean. Parametric data were tested using analysis of variance, followed by Bonferroni posthoc tests, to determine differences between groups. Statistical significance was established at p # 0.05. RESULTS: MRI indices (NP area x signal intensity) were significantly higher (p!0.05) for injured discs treated with PDGF-BB, compared to injured discs treated with HA only or saline at both 4 and 8 weeks after treatment. Biomechanical assessments found fewer indicators of degeneration in PDGF-BB and PDGF-BB/HA treated discs at 4 and 8 weeks, compared to HA-only and saline controls at 4 weeks. Control discs demonstrated progressive degeneration at 8 weeks, with evidence of creep-loading deficiencies. PDGF-BB and PDGF-BB/HA treated discs further showed a significant increase (p!0.05) in compressive strength to failure, compared to HA-only and saline controls. PDGF-BB/HA treated IVDs demonstrated trends toward decreased severity of degeneration compared to PDGFBB-only treated IVDs. However, these differences did not reach statistical significance. CONCLUSIONS: The results of this study suggest that PDGF-BB significantly decreases several indicators of disc degeneration in vivo, including MRI indices and disc biomechanics. Some of these parameters
P124. Magnetic Resonance Neurography Allows Visualization of the Lumbar Plexus at the L4-5 Disc Space: Development of a Preoperative Surgical Planning Tool for Lateral Transpsoas Interbody Fusion John C. Quinn, MD1, Joseph L. Chazen, MD2, Darren R. Lebl, MD3; 1Glen Ridge, NJ, US; 2Weill Cornell Medical College, New York, NY, US; 3New York, NY, US BACKGROUND CONTEXT: The lateral retroperitoneal tranpsoas approach for lumbar interbody fusion is a minimally invasive surgical technique that is now frequently used to treat common spinal disorders. One limitation of this approach is the close proximity of the lumbar plexus to the surgical corridor and the risk of iatrogenic neurological injury. Overall, the reported incidence of iatrogenic neurological deficit in the literature ranges from 20% to 75%. Real-time neural monitoring can decrease the incidence of such injuries; however, postoperative deficits can still occur and the true incidence may be under-reported. Previous studies have described an anatomical ‘‘safe zone’’ relative to the disc space at each level. Several studies have suggested that this window of the ‘‘safe zone’’ narrows with progression caudally toward the L4-5 level. This is reflected in the prevalence of femoral nerve injuries associated with the lateral transpsoas approach. PURPOSE: Current techniques of assessing the proximity of neural tissue to the L4-5 disc space have limited capabilities. Magnetic resonance neurography has been used as a noninvasive tool for the evaluation of lumbosacral plexopathy, and as a surgical planning tool for patients with peripheral nerve entrapments or peripheral nerve tumors. The ability to visualize the position of the lumbar plexus overlying the disc space from a surgical corridor view could be useful in the preoperative planning for patients undergoing lateral transpsoas interbody fusion. The purpose of this study is to introduce a novel imaging/ image processing technique for defining the anatomic relationship of lumbar plexus to the lumbar disc space in the preoperative planning of lateral access surgery. By providing the surgeon with a preoperative anatomic map of the lumbar plexus overlying the disc space, MR neurography may improve the safety profile of lateral access procedures. METHODS: A total of 10 consecutive lumbar plexus (20 sides) MR neurograms were reviewed. All scans were performed on a Siemens 3-Tesla Skyra MRI. The imaging protocol included multiplanar T1-weighted and T2 weighted spectral adiabatic inversion recovery (SPAIR; Siemans Healthcare). Following image acquisistion, image fusion and modeling was performed using TeraRecon Aquarius iNtuition v4.4. 3D models of the lumbar plexus overlying the L4-5 disc space were created using the General Electric AW Suite v2. RESULTS: In all patients, 3D reconstructions of MR neurograms were created and the course of the lumbar plexus overlying the disc space was visualized. The disc space in a sagittal view was divided into 5 zones, and the relationship of the lumbar plexus to the overlying disc space was recorded. CONCLUSIONS: Lumbar plexus neurography is a noninvasive imaging technique for visualizing the lumbosacral plexus and its relationship to the disc space. The ability to assess the location of the plexus preoperatively, may aid in preoperative planning and risk assessment and potentially reduce the incidence of approach related postoperative neurological deficits. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs. http://dx.doi.org/10.1016/j.spinee.2014.08.378
Refer to onsite Annual Meeting presentations and postmeeting proceedings for possible referenced figures and tables. Authors are responsible for accurately reporting disclosures and FDA device/drug status at time of abstract submission.
155S
PATIENT SAMPLE: From June 2010 to October 2012, 49 patients underwent navigated MIS SI joint fusions by a single surgeon. One was lost to follow-up and excluded. OUTCOME MEASURES: Oswestry Disability Index (ODI) and Visual Analog Scale (VAS) scores. METHODS: A consecutive case series of patients were reviewed. Statistical comparisons on Oswestry Disability Index (ODI) and Visual Analog Scale (VAS) scores explored differences in patients with or without a prior history of lower back surgery. RESULTS: Patients’ average age was 48 years (range 18-77), with 13 males and 35 females. 62.5% (30/48) had a history of back or hip surgery, while 37.5% (18/48) had isolated SI joint disease. 56% (27/48) were unilateral and 44% (21/48) were bilateral. Revision rate was 8% (4/48) with 2 unilateral and 2 bilateral MIS revisions. Among bilateral procedures, there were 3 simultaneous, 4 contralateral sides by other surgeons, and 1 revision by another surgeon. Average time to contralateral SI joint fusion was 6 months (range 1-12). Mean change in ODI and VAS scores did not differ significantly by surgical history (ODID 11619 vs 9613; VASD 2.562.4 vs 1.362.2; pO0.05), although scores tended to be better in patients with isolated SI joint disease. CONCLUSIONS: More patients undergoing MIS SI joint fusions have a history of lumbar or hip surgery, which likely affects patient outcomes scores, especially ODI. Both VAS and ODI scores at final follow-up tended to be better in patients with isolated SI joint disease. However, the ODI and VAS may not be adequate measurement for patients with bilateral SI joint disease, or concomitant lumbar and/or hip disease undergoing unilateral SI joint fusion. When considering SI joint fusion, a history of lumbar surgery or disease can be a factor in outcomes. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs.
VEGF expression at 3, 7 and 14 days was significantly higher than that at 24 hours. The majority of neural cells demonstrated hypoxia accompanied with brown HIF-1a positive staining in the local injured cord segment. A profoundly hypoxemic metabolism condition at 1 and 3 day postinjury is suggested due to the peak counts of positive HIF-1a cells rate. CONCLUSIONS: 1. Trauma directly causes structural and volumetric damage to the microvasculature in the rat SCI model. 2. The injured spinal cord was trapped in serious hypoxia due to the local microcirculatory disorder during the acute SCI process. 3. Post-traumatic angiogenesis probably served as an inherent mechanism to promote the vascular remodeling, which was closely correlated with the hypoxia regulatory mechanism. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs.
http://dx.doi.org/10.1016/j.spinee.2014.08.374
BACKGROUND CONTEXT: The thoracolumbar injury classification system (TLICS) was developed to improve the categorization and management of thoracolumbar trauma. TLICS has been shown to have good reliability and validity in the adult population. PURPOSE: The purpose of this study was to determine the clinical applicability of the TLICS in pediatric spine trauma. STUDY DESIGN/SETTING: TLICS was prospectively evaluated using 20 nonconsecutive pediatric spine trauma case examples. PATIENT SAMPLE: 20 cases of pediatric spine trauma. OUTCOME MEASURES: Reliability and validity (Kappa coefficient). METHODS: The clinical and radiographic findings of 20 pediatric thoracolumbar fractures were prospectively presented to 20 surgeons with varying levels of training and experience with spinal trauma. These injuries were consecutively scored using the TLICS. Cohen’s unweighted kappa coefficients and Spearman’s rank order correlation values were calculated for the key parameters (injury morphology, status of PLC, neurological status, and proposed management) to assess the inter-rater reliabilities. Five surgeons scored the same cases 2 months later to assess the intra-rater reliability. The actual management of each case was then compared with the treatment recommended by the TLICS algorithm to assess validity. RESULTS: The inter-rater kappa statistics of all subgroups (injury morphology, status of the posterior ligamentous complex, neurological status, and proposed treatment) were within the range of moderate to substantial reproducibility (0.449-0.958). Proposed treatment had the lowest interrater agreement (0.449). All subgroups had excellent intra-rater reliability (0.748-1.000). The various indices for validity were calculated (80.3% correct, 0.836 sensitivity, 0.785 specificity, 0.676 positive predictive value, 0.899 negative predictive value). CONCLUSIONS: The thoracolumbar injury classification system has good reliability and validity when used in the pediatric population. The inter-rater reliability of predicting management and indices for validity are lower than in adults with thoracolumbar fractures, which is likely due to differences in the way children are treated for certain types of injuries. TLICS can be used to reliably categorize thoracolumbar injuries in the pediatric population; however, modifications may be needed to better guide treatment in this specific patient population.
P121. Post-traumatic Angiogenesis Correlated with Hypoxia Regulation after Acute Spinal Cord Injury in Rat Hongbin Lu, MD, PhD; Changsha, China PURPOSE: To investigate the post-traumatic angiogenesis and correlated regulatory mechanism in a rat model of acute spinal cord injury (SCI). METHODS: 1. Rat SCI Modeling and Groups: 64 SD rats were subjected to the modified Allen’s weight impacting to induce an incomplete SCI model. The other 16 rats only underwent laminotomy to serve as a sham group. The T10 cord samples were harvested at 1, 3, 7 and 14 day postinjury (n54, respectively). 2. Micro-CT Detection and Thick Tissue Section: the samples with angiography underwent micro-CT imaging for 3D vascular rendering, followed by thick section for microscopy observation. The quantitative parameters including vascular volume fraction (VVF), thickness, separation and connectivity were analyzed by microview software package. 3. Immunofluorescent Staining: the RECA-1 antibody was used to label the endothelial cells for microvessel staining, and DAPI for cell nucleus, and the VEGF proteins were labeled to green. The integrated optical density (IOD) was calculated to evaluate the VEGF expression, and the vessel with RECA-1 positive staining was counted by IPP software. 4. Immunohistochemical Staining: the brown cells were counted and identified as positive HIF-1a staining. 5. Western Blot: the pro-angiogenesis correlated factors, including HIF-1a, PGC-1a, ERR-a and VEGF, underwent WB electrophoresis to analyze the semi-quantitative expression level. 6. Statistical analysis was carried out with SPSS 13.0 software, P＜0.05 was interpreted as significant. RESULTS: The distribution of RECA-1 and VEGF positive staining was stated. The microvessel numbers significantly decreased at 24 hours postinjury, and gradually recovered with the healing time implying a post-traumatic angiogenesis. VEGF seemed to be expressed in various neural cells, in which the VEGF positive astrocytes were subsequently activated instead of the degeneration of neurons. The value of integrated optical density of
http://dx.doi.org/10.1016/j.spinee.2014.08.375
P122. Reliability and Validity of the Thoracolumbar Injury Classification System in Pediatric Spine Trauma Jason W. Savage, MD1, Paul M. Arnold, MD2, Wellington K. Hsu, MD3, Alpesh A. Patel, MD, FACS4, Gregory D. Schroeder, MD3, Alexander R. Vaccaro, MD, PhD5, John R. Dimar, II, MD6, Paul A. Anderson, MD7; 1 Chicago, IL, US; 2University of Kansas Medical Center Department of Neurosurgery, Kansas City, KS, US; 3Northwestern University, Chicago, IL, US; 4Northwestern Department of Orthopaedics, Chicago, IL, US; 5 Rothman Institute, Philadelphia, PA, US; 6Spine Institute, Louisville, KY, US; 7University of Wisconsin Orthopedics and Rehabilitation, Madison, WI, US
Refer to onsite Annual Meeting presentations and postmeeting proceedings for possible referenced figures and tables. Authors are responsible for accurately reporting disclosures and FDA device/drug status at time of abstract submission.
156S
Proceedings of the NASS 29th Annual Meeting / The Spine Journal 14 (2014) 1S–183S
FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs.
may be enhanced when PDGF-BB is delivered in a thiol-modified HA hydrogel. FDA DEVICE/DRUG STATUS: PDGF-BB (Investigational/Not approved)
http://dx.doi.org/10.1016/j.spinee.2014.08.376 http://dx.doi.org/10.1016/j.spinee.2014.08.377 P123. Treatment of Injured Intervertebral Discs with PDGF-BB Inhibits Degeneration In Vivo Isaac Moss, MD1, David N. Paglia, PhD2, Hicham Drissi, PhD2; 1Medical Arts and Research Building, Farmington, CT, US; 2University of Connecticut Health Center, Farmington, CT, US BACKGROUND CONTEXT: Back pain is a leading cause of disability in the US. Intervertebral disc (IVD) degeneration is recognized as a major contributing factor to this disorder. Several growth factors have demonstrated the potential to slow or reverse the degenerative processes in vitro and in vivo. Platelet-derived growth factor BB (PDGF-BB), thought to be the primary active component of platelet rich plasma, has been shown to slow the degenerative process, by inhibiting IVD cell apoptosis, and increasing cell proliferation and extracellular matrix (ECM) formation in monolayer and 3-D pellet culture. PURPOSE: The goal of this study was to examine the effect of PDGF-BB in a preclinical model of IVD degeneration. Our hypotheses were that treatment of injured IVDs during midstage disc degeneration would inhibit degeneration; and that these effects could be enhanced when PDGF-BB was administered in combination with a hydrogel capable of gradual release of the growth factor over an extended period. STUDY DESIGN/SETTING: In vivo, preclinical model. PATIENT SAMPLE: New Zealand White Rabbits. OUTCOME MEASURES: MRI, biomechanical testing. METHODS: After institutional animal care committee approval, the welldescribed rabbit annular puncture model of disc degeneration was employed to de-nucleate four lumbar IVDs (L2-3 to L6-7) in New Zealand White Rabbits. Four weeks after the discs were injured (corresponding to mid-stage degeneration), 20 microliters of either: I) sterile saline, II) 1 ng/mL recombinant human PDGF-BB (rhPDGF-BB, Pepro Tech Inc., Rocky Hill, NJ), III) thiol-modified hyaluronic acid (HA, Glycosan, Alameda, CA) hydrogel material, or IV) 1 ng/mL PDGF in the HA hydrogel, were injected into the IVDs from the contralateral side. Rabbits were euthanized at 4 and 8 weeks after intradiscal treatments. Following MRI imaging, the lumbar spines were harvested for histology and biomechanical analyses. MR Images were analyzed to determine the nucleus pulposus area and T2-weighted signal intensity (n512 per group). Uniaxial compressive loading (cyclic strain, creep, and load to failure) was used to determine biomechanical disc integrity and the extent of IVD degeneration (n56 per group). All data were given as means 6 standard deviation of the mean. Parametric data were tested using analysis of variance, followed by Bonferroni posthoc tests, to determine differences between groups. Statistical significance was established at p # 0.05. RESULTS: MRI indices (NP area x signal intensity) were significantly higher (p!0.05) for injured discs treated with PDGF-BB, compared to injured discs treated with HA only or saline at both 4 and 8 weeks after treatment. Biomechanical assessments found fewer indicators of degeneration in PDGF-BB and PDGF-BB/HA treated discs at 4 and 8 weeks, compared to HA-only and saline controls at 4 weeks. Control discs demonstrated progressive degeneration at 8 weeks, with evidence of creep-loading deficiencies. PDGF-BB and PDGF-BB/HA treated discs further showed a significant increase (p!0.05) in compressive strength to failure, compared to HA-only and saline controls. PDGF-BB/HA treated IVDs demonstrated trends toward decreased severity of degeneration compared to PDGFBB-only treated IVDs. However, these differences did not reach statistical significance. CONCLUSIONS: The results of this study suggest that PDGF-BB significantly decreases several indicators of disc degeneration in vivo, including MRI indices and disc biomechanics. Some of these parameters
P124. Magnetic Resonance Neurography Allows Visualization of the Lumbar Plexus at the L4-5 Disc Space: Development of a Preoperative Surgical Planning Tool for Lateral Transpsoas Interbody Fusion John C. Quinn, MD1, Joseph L. Chazen, MD2, Darren R. Lebl, MD3; 1Glen Ridge, NJ, US; 2Weill Cornell Medical College, New York, NY, US; 3New York, NY, US BACKGROUND CONTEXT: The lateral retroperitoneal tranpsoas approach for lumbar interbody fusion is a minimally invasive surgical technique that is now frequently used to treat common spinal disorders. One limitation of this approach is the close proximity of the lumbar plexus to the surgical corridor and the risk of iatrogenic neurological injury. Overall, the reported incidence of iatrogenic neurological deficit in the literature ranges from 20% to 75%. Real-time neural monitoring can decrease the incidence of such injuries; however, postoperative deficits can still occur and the true incidence may be under-reported. Previous studies have described an anatomical ‘‘safe zone’’ relative to the disc space at each level. Several studies have suggested that this window of the ‘‘safe zone’’ narrows with progression caudally toward the L4-5 level. This is reflected in the prevalence of femoral nerve injuries associated with the lateral transpsoas approach. PURPOSE: Current techniques of assessing the proximity of neural tissue to the L4-5 disc space have limited capabilities. Magnetic resonance neurography has been used as a noninvasive tool for the evaluation of lumbosacral plexopathy, and as a surgical planning tool for patients with peripheral nerve entrapments or peripheral nerve tumors. The ability to visualize the position of the lumbar plexus overlying the disc space from a surgical corridor view could be useful in the preoperative planning for patients undergoing lateral transpsoas interbody fusion. The purpose of this study is to introduce a novel imaging/ image processing technique for defining the anatomic relationship of lumbar plexus to the lumbar disc space in the preoperative planning of lateral access surgery. By providing the surgeon with a preoperative anatomic map of the lumbar plexus overlying the disc space, MR neurography may improve the safety profile of lateral access procedures. METHODS: A total of 10 consecutive lumbar plexus (20 sides) MR neurograms were reviewed. All scans were performed on a Siemens 3-Tesla Skyra MRI. The imaging protocol included multiplanar T1-weighted and T2 weighted spectral adiabatic inversion recovery (SPAIR; Siemans Healthcare). Following image acquisistion, image fusion and modeling was performed using TeraRecon Aquarius iNtuition v4.4. 3D models of the lumbar plexus overlying the L4-5 disc space were created using the General Electric AW Suite v2. RESULTS: In all patients, 3D reconstructions of MR neurograms were created and the course of the lumbar plexus overlying the disc space was visualized. The disc space in a sagittal view was divided into 5 zones, and the relationship of the lumbar plexus to the overlying disc space was recorded. CONCLUSIONS: Lumbar plexus neurography is a noninvasive imaging technique for visualizing the lumbosacral plexus and its relationship to the disc space. The ability to assess the location of the plexus preoperatively, may aid in preoperative planning and risk assessment and potentially reduce the incidence of approach related postoperative neurological deficits. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs. http://dx.doi.org/10.1016/j.spinee.2014.08.378
Refer to onsite Annual Meeting presentations and postmeeting proceedings for possible referenced figures and tables. Authors are responsible for accurately reporting disclosures and FDA device/drug status at time of abstract submission.