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Lumbar Plexus Palsy after XLIF: An Avoidable Complication?
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Proceedings of the NASS 25th Annual Meeting / The Spine Journal 10 (2010) 1S–149S
P79. Transpedicular Screw Fixation in Thoracolumbar Burst Fractures: Is There a Difference in Radiological Outcome between Two-level and Three-level Construct? Rachid Mahdad, MD, Miranda Kusters, MD, PhD, Sander P.D. Dijkstra, MD, PhD; Leiden University Medical Centre, Leiden, Netherlands BACKGROUND CONTEXT: Transpedicular screw fixation with screws in the adjacent vertebral bodies of the thoracolumbar burst fracture (four point fixation) has been widely used to achieve direct stability and to restore alignment with reduction in the fractured segment. Kyphosis and wedge angle are corrected after surgery, but decline within one year postoperatively. Biomechanical studies have shown greater reduction and increased construct stiffness when an additional intermediate screw is placed in the fractured level (six point fixation), but clinical and radiological data is lacking. This is the first study to compare these two different techniques in thoracolumbar burst fractures. Better radiological outcomes in the second group could implement better clinical long-term results for thoracolumbar burst fractures. PURPOSE: To compare radiological outcomes of two-level fixation (four points) versus three-level fixation (six points) using pedicle screws in the treatment of thoracolumbar burst fractures. STUDY DESIGN/SETTING: A retrospective case control study. PATIENT SAMPLE: Two cohort groups. The first with an operation between 1987 and 2002. The second with an operation between 2002 and 2008. OUTCOME MEASURES: Correction of wedge and kyphosis angle one month and twelve months after surgery. METHODS: We selected two cohort groups. The first consisted of twenty patients operated on between 1987 and 2002 with four point fixation. The second group of nineteen patients were operated between 2002 and 2008 with six point fixation. The pre- and postoperative wedge and kyphosis angles are compared in the two groups. The postoperative wedge and kyphosis are measured after one month and after twelve months. RESULTS: We compared twenty patients with four point fixation and nineteen patients with six point fixation. The most fractures were located in Th12, L1 and L2. Wedge and kyphosis angle reduction was not statistically significant different between the two groups after one month and after one year. Results are shown in the figure below. There was a significant reduction in wedge directly after reduction (p50,001 for both groups) and after one year (p50.002 for both groups). Furthermore, we observed an improvement of the kyphosis angle in both groups after 1 month (p# 0.016), but not significant after 12 months (p!0.19). CONCLUSIONS: We conclude that the six point fixation technique is equal to the four point fixation technique in terms of wedge and kyphosis angle after surgery. This reduction sustained for the wedge angle but not for the kyphosis angle after one year. We found no evidence that six point fixation has better biomechanical properties within one year after surgery. Prospective randomized studies are necessary to confirm long-term radiological and clinical outcomes. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs.
core of nucleus pulposus (NP) cells in a gelatinous matrix, a surrounding layer of fibrocartilaginous annulus fibrosus (AF) cells between adjacent vertebrae, and a mineralized endplate (EP) over the surfaces of adjacent vertebrae. NP cells are known to originate from embryonic notochord cells that act during embryogenesis as an important signaling center and secrete sonic hedgehog (Shh) which is required for patterning of neural crest and somites. PURPOSE: We hypothesize that NP cells continue to be an active signaling center during the postnatal stages, and are required for the maintenance of the AF and EP cells. To test this hypothesis we have established an in vitro system to culture neonatal mouse discs. STUDY DESIGN/SETTING: Newborn mice discs were cultured on Collagen IV coated inserts in medium. OUTCOME MEASURES: With this knowledge we will design molecular treatments for disc injury aimed at regenerating (healing) the disc along the pathway it followed during its original postnatal development. Understanding the molecular mechanism of disc growth will help design experiments to delineate what goes wrong during degeneration of the disc. METHODS: Lumbar discs from neonatal mice of postnatal age 1–4 days were dissected and cultured in DMEM Ham F-12 medium, either in the presence of fetal calf serum (FCS) or insuline-transferrin-sodium selenite (ITS) supplement, at 37 C in 5% CO2 for 2, 4, 6 and 8 days on Collagen IV coated cell culture inserts. At the end of the culture the discs were removed, washed thrice in buffered saline and snap frozen in OCT molds. Cryosections were collected at 8 mm thickness. Immunostaining was carried out using specific primary antibodies. Cy5 conjugated secondary antibodies were used for signal detection, and nuclei were counter stained with POPO3-iodieTM. Imaging was carried out using confocal microscope. RESULTS: Immunostaining showed that the NP cell markers like Brachyury, Shh and cytokeratin 19 were expressed at all the time points. And the absence of FCS did not affect the expression. In our previous study we showed that the disc cells are actively responding to several major signaling pathways during the early postnatal ages. Major cell signaling pathways including BMP and TGFb were analyzed using antibodies against the activated cytoplasmic messengers: phospho-Smad 1, 5, & 8 and phospho-Smad 2 & 3 respectively. All the components of the disc responded to these signals produced by the NP cells. As the disc grows, there are changes in the matrix assembly, and this was monitored by assaying for the collagen I and II accumulation in the AF cells. Increase in collagen I and II was observed with the duration of the culture, both with or without the FCS. CONCLUSIONS: Results show that the NP cells continue to express their characteristic molecular markers, and the disc continues to grow in vitro even in the absence of the serum. This provides an excellent model system to study the role of specific signals for disc maintenance by use of antagonists or inhibitors. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs. doi: 10.1016/j.spinee.2010.07.356
doi: 10.1016/j.spinee.2010.07.355
P80. In Vitro Model System to Study Mouse Intervertebral Disc Growth Chitra Dahia, PhD, Eric Mahoney, Eric Wall, MD, Christopher Wylie; Cincinnati Children’s Hospital Medical Center, Cincinnati, OH, USA BACKGROUND CONTEXT: Degenerative disc disease afflicts 1 in 7 adults and is the leading cause of disability and back pain. However the molecular signals that guide the normal development of the disc, and the molecular signals involved in disc degeneration are not well defined. We have standardized a model system to study these processes during the postnatal development of mouse disc. The IVD has three components: a central
P81. Lumbar Plexus Palsy after XLIF: An Avoidable Complication? Jeffrey D. Coe, MD1, S. Craig Meyer, MD2; 1Silicon Valley Spine Institute, Campbell, CA, USA; 2Columbia Orthopaedic Group, Columbia, MO, USA BACKGROUND CONTEXT: XLIF via a minimally invasive transpsoas approach has gained wide acceptance in the last three to five years as an alternative to ALIF, PLIF and TLIF for interbody fusion of the lumbar spine (exclusive of L5-S1). Continuous & evoked EMG monitoring ostensibly allows safe navigation through the psoas muscle anterior to the lumbar plexus by detecting proximity and thereby avoiding injury to the lumbar plexus. Despite the use of EMG monitoring, however, the authors have noted several cases of lumbar plexus injury with XLIF.
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 25th Annual Meeting / The Spine Journal 10 (2010) 1S–149S PURPOSE: To evaluate the anatomic and technical factors leading to lumbar plexus injury with XLIF as well as the prognosis for recovery. STUDY DESIGN/SETTING: See methods. PATIENT SAMPLE: The first 100 consecutive cases of XLIF performed by the authors with a minimum of 15 months follow-up. The mean age was 57.8 years (range 26 to 80 years). All but three patients also underwent either supplemental lateral plating and/or PSF with pedicle screw fixation. No lateral plates were used at the L4-5 level, however. The mean number of operated levels (XLIF) was 1.8 (range 1 to 6). OUTCOME MEASURES: See methods. METHODS: All patients were observed for neurologic complications, particularly quadriceps weakness as well as subsequent recovery. The factors leading to quadriceps weakness were assessed including any cases in which stimulation thresholds with EMG monitoring were 5 Ma or less. RESULTS: Three of the 100 total patients (3.0%) were noted to have significant quadriceps weakness lasting longer than 6 weeks that required the use of assistive devices for greater than two weeks. In all three the L4-5 level was included in the fusion, representing 3.8% of the 78 patients that included L4-5 as an operated level. In each of these patients, the L4-5 level was noted to be anatomically challenging, requiring aggressive table flexion to access the disc. Also, each of these patients had EMG stimulation thresholds #5 Ma during the approach, mandating anterior transpsoas penetration and thus posterior retraction of the bulk of the psoas muscle to access the disc. All three patients experienced sufficient recovery by 6 months such that assistive devices were no longer required for ambulation. CONCLUSIONS: XLIF is a safe alternative to other approaches for lumbar interbody reconstruction and fusion. It has a much lower risk of vascular injury as compared to traditional ALIF and virtually no risk of injury to the cauda equina as compared to PLIF & TLIF. There is, however, a risk of lumbar plexus injury that is somewhat unique to the transpsoas approach used in XLIF. XLIF carries a risk of lumbar plexus injury that is reduced, but not eliminated, by the use of EMG monitoring; with L45 being the most susceptible level. The authors hypothesize that the risk of lumbar injury is associated with a combination of compression of the lumbar plexus (resulting from posterior retraction) and lumbar plexus stretch from aggressive table flexion. Fortunately, the prognosis for recovery from this injury is excellent. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs. doi: 10.1016/j.spinee.2010.07.357
P82. Is Spinal Motion Limited by Contemporary Lumbosacral Orthoses? A Comparison of Three Braces John Hipp, PhD1, Tom Dibello, CO2, David Dice, MD1, Charles A. Reitman, MD1, Jacob Weinberg, MD1; 1Orthopedic Surgery, Baylor College of Medicine, Houston, TX, USA; 2Dynamic Orthotics and Prosthetics, LP, Houston, TX, USA BACKGROUND CONTEXT: External braces are frequently used to immobilize the lumbosacral spine. Three contemporary lumbosacral orthotic (LSO) designs include the Boston Overlap Brace (Boston BraceÔ), Boston Overlap Brace with a thigh extension, and the Gomez Pelvic Sacral (GPS) brace with a sacrococcygeal extension (Gomez Orthotics SystemÔ). These three brace designs may have different abilities to externally immobilize the lumbosacral spine. PURPOSE: To study the effect of each brace type on limiting motion in the lumbosacral spine. STUDY DESIGN/SETTING: Observational study. PATIENT SAMPLE: Twelve adult volunteers were recruited for this study. The average age was 30 years and the mean BMI was 24.5 kg/m2. The volunteers had no history of back pain or radiographic evidence of pathology in the lumbosacral spine. OUTCOME MEASURES: Intervertebral motion at L4-5 and L5-S1.
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METHODS: Volunteers were measured, fitted, and placed in each of the three brace types by a licensed orthotist for a minimum of 10 minutes. The thigh extension was set to allow motion from 0-30 degrees of hip flexion. Flexion and extension radiographs of the lumbar spine were obtained with each of the three braces. Intervertebral motion was measured from the flexion/extension radiographs using previously validated computer-assisted methods (QMAÔ, Medical Metrics, Inc). At each intervertebral level, measurements included change in anterior disc height, change in posterior disc height, rotation, and shear. This motion was compared to previous data of unbraced volunteers. RESULTS: There was significantly less motion at L4-L5 in the Boston Overlap Brace with a thigh extension compared to the Boston Overlap Brace alone (P50.03). There were no other significant differences, although there was a trend for less motion with the GPS brace compared to the Boston Overlap brace (P50.15). There were no significant differences in motion restriction between these braces at L5-S1 (P50.18). The intervertebral rotation and translation in these volunteers wearing a brace was within the 95% confidence intervals established for unbraced volunteers. CONCLUSIONS: Differences between these braces may be detected at L4-L5. However, in general, these orthoses do not significantly restrict intervertebral motion in the lumbosacral spine. Successful lumbosacral bracing may require further study. FDA DEVICE/DRUG STATUS: Boston Overlap Brace, Boston Overlap Brace with thigh extension, Gomez Pelvic Sacral (GPS) brace: Approved for this indication. doi: 10.1016/j.spinee.2010.07.358
P83. 2-Year Results from Four IDE Study Sites: CerviCoreÒ Intervertebral Disc vs. Fusion Jean-Jacques Abitbol, MD1, Joseph C. Maroon, MD2, Willie S. Edwards, MD3, Jeffrey S. Fischgrund, MD4; 1 California Spine, San Diego, CA, USA; 2Tri-State Neurosurgical Associates - UPMC, Pittsburgh, PA, USA; 3Pee Dee Spine Center, Florence, SC, USA; 4Michigan Orthopaedic Institute, Southfield, MI, USA BACKGROUND CONTEXT: The CerviCoreÒ Intervertebral Disc is intended to replace a single cervical intervertebral disc between C3 and C7 in skeletally mature patients, increase and maintain disc height, reduce upper extremity radicular symptoms, improve function, and permit movement of the treated spine segment. PURPOSE: This study compares the CerviCoreÒ Intervertebral Disc to the gold standard of ACDF, for single-level treatment of cervical radicular symptoms. STUDY DESIGN/SETTING: Data was collected from four of the CerviCoreÒ IDE study sites, which was a multi-center, prospective, randomized, controlled clinical trial conducted at 25 centers in the United States. PATIENT SAMPLE: At our four sites, data is available for: 49 CerviCoreÒ patients and 49 ACDF patients at baseline and 31 CerviCoreÒ and 26 ACDF patients at 2 years. OUTCOME MEASURES: Functionality was assessed with NDI and upper extremity pain was measured using worse arm (at pre-op) VAS. METHODS: Subjects who qualified were evaluated pre-operatively at 6 weeks, 3 months, 6 months, 12 months, and 24 months post-operatively. Complications and adverse events were evaluated over the course of the clinical trial. RESULTS: Within each treatment group, the mean NDI and Worse Arm VAS results were significantly different from pre-op at all visits up to 2 years (p!.0001). The mean NDI scores (CerviCoreÒ vs. fusion) were: 54 vs. 53 at pre-op. At 2 years, mean scores were 13 vs. 17. Differences between and within groups were not significant. The mean Worse Arm VAS scores were: 77 vs. 69 at pre-op and 16 vs. 17 at the 2 year follow-up. The difference between groups was significant at 6 weeks (p5.0483), where CerviCoreÒ group’s mean change from baseline was
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 25th Annual Meeting / The Spine Journal 10 (2010) 1S–149S
P79. Transpedicular Screw Fixation in Thoracolumbar Burst Fractures: Is There a Difference in Radiological Outcome between Two-level and Three-level Construct? Rachid Mahdad, MD, Miranda Kusters, MD, PhD, Sander P.D. Dijkstra, MD, PhD; Leiden University Medical Centre, Leiden, Netherlands BACKGROUND CONTEXT: Transpedicular screw fixation with screws in the adjacent vertebral bodies of the thoracolumbar burst fracture (four point fixation) has been widely used to achieve direct stability and to restore alignment with reduction in the fractured segment. Kyphosis and wedge angle are corrected after surgery, but decline within one year postoperatively. Biomechanical studies have shown greater reduction and increased construct stiffness when an additional intermediate screw is placed in the fractured level (six point fixation), but clinical and radiological data is lacking. This is the first study to compare these two different techniques in thoracolumbar burst fractures. Better radiological outcomes in the second group could implement better clinical long-term results for thoracolumbar burst fractures. PURPOSE: To compare radiological outcomes of two-level fixation (four points) versus three-level fixation (six points) using pedicle screws in the treatment of thoracolumbar burst fractures. STUDY DESIGN/SETTING: A retrospective case control study. PATIENT SAMPLE: Two cohort groups. The first with an operation between 1987 and 2002. The second with an operation between 2002 and 2008. OUTCOME MEASURES: Correction of wedge and kyphosis angle one month and twelve months after surgery. METHODS: We selected two cohort groups. The first consisted of twenty patients operated on between 1987 and 2002 with four point fixation. The second group of nineteen patients were operated between 2002 and 2008 with six point fixation. The pre- and postoperative wedge and kyphosis angles are compared in the two groups. The postoperative wedge and kyphosis are measured after one month and after twelve months. RESULTS: We compared twenty patients with four point fixation and nineteen patients with six point fixation. The most fractures were located in Th12, L1 and L2. Wedge and kyphosis angle reduction was not statistically significant different between the two groups after one month and after one year. Results are shown in the figure below. There was a significant reduction in wedge directly after reduction (p50,001 for both groups) and after one year (p50.002 for both groups). Furthermore, we observed an improvement of the kyphosis angle in both groups after 1 month (p# 0.016), but not significant after 12 months (p!0.19). CONCLUSIONS: We conclude that the six point fixation technique is equal to the four point fixation technique in terms of wedge and kyphosis angle after surgery. This reduction sustained for the wedge angle but not for the kyphosis angle after one year. We found no evidence that six point fixation has better biomechanical properties within one year after surgery. Prospective randomized studies are necessary to confirm long-term radiological and clinical outcomes. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs.
core of nucleus pulposus (NP) cells in a gelatinous matrix, a surrounding layer of fibrocartilaginous annulus fibrosus (AF) cells between adjacent vertebrae, and a mineralized endplate (EP) over the surfaces of adjacent vertebrae. NP cells are known to originate from embryonic notochord cells that act during embryogenesis as an important signaling center and secrete sonic hedgehog (Shh) which is required for patterning of neural crest and somites. PURPOSE: We hypothesize that NP cells continue to be an active signaling center during the postnatal stages, and are required for the maintenance of the AF and EP cells. To test this hypothesis we have established an in vitro system to culture neonatal mouse discs. STUDY DESIGN/SETTING: Newborn mice discs were cultured on Collagen IV coated inserts in medium. OUTCOME MEASURES: With this knowledge we will design molecular treatments for disc injury aimed at regenerating (healing) the disc along the pathway it followed during its original postnatal development. Understanding the molecular mechanism of disc growth will help design experiments to delineate what goes wrong during degeneration of the disc. METHODS: Lumbar discs from neonatal mice of postnatal age 1–4 days were dissected and cultured in DMEM Ham F-12 medium, either in the presence of fetal calf serum (FCS) or insuline-transferrin-sodium selenite (ITS) supplement, at 37 C in 5% CO2 for 2, 4, 6 and 8 days on Collagen IV coated cell culture inserts. At the end of the culture the discs were removed, washed thrice in buffered saline and snap frozen in OCT molds. Cryosections were collected at 8 mm thickness. Immunostaining was carried out using specific primary antibodies. Cy5 conjugated secondary antibodies were used for signal detection, and nuclei were counter stained with POPO3-iodieTM. Imaging was carried out using confocal microscope. RESULTS: Immunostaining showed that the NP cell markers like Brachyury, Shh and cytokeratin 19 were expressed at all the time points. And the absence of FCS did not affect the expression. In our previous study we showed that the disc cells are actively responding to several major signaling pathways during the early postnatal ages. Major cell signaling pathways including BMP and TGFb were analyzed using antibodies against the activated cytoplasmic messengers: phospho-Smad 1, 5, & 8 and phospho-Smad 2 & 3 respectively. All the components of the disc responded to these signals produced by the NP cells. As the disc grows, there are changes in the matrix assembly, and this was monitored by assaying for the collagen I and II accumulation in the AF cells. Increase in collagen I and II was observed with the duration of the culture, both with or without the FCS. CONCLUSIONS: Results show that the NP cells continue to express their characteristic molecular markers, and the disc continues to grow in vitro even in the absence of the serum. This provides an excellent model system to study the role of specific signals for disc maintenance by use of antagonists or inhibitors. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs. doi: 10.1016/j.spinee.2010.07.356
doi: 10.1016/j.spinee.2010.07.355
P80. In Vitro Model System to Study Mouse Intervertebral Disc Growth Chitra Dahia, PhD, Eric Mahoney, Eric Wall, MD, Christopher Wylie; Cincinnati Children’s Hospital Medical Center, Cincinnati, OH, USA BACKGROUND CONTEXT: Degenerative disc disease afflicts 1 in 7 adults and is the leading cause of disability and back pain. However the molecular signals that guide the normal development of the disc, and the molecular signals involved in disc degeneration are not well defined. We have standardized a model system to study these processes during the postnatal development of mouse disc. The IVD has three components: a central
P81. Lumbar Plexus Palsy after XLIF: An Avoidable Complication? Jeffrey D. Coe, MD1, S. Craig Meyer, MD2; 1Silicon Valley Spine Institute, Campbell, CA, USA; 2Columbia Orthopaedic Group, Columbia, MO, USA BACKGROUND CONTEXT: XLIF via a minimally invasive transpsoas approach has gained wide acceptance in the last three to five years as an alternative to ALIF, PLIF and TLIF for interbody fusion of the lumbar spine (exclusive of L5-S1). Continuous & evoked EMG monitoring ostensibly allows safe navigation through the psoas muscle anterior to the lumbar plexus by detecting proximity and thereby avoiding injury to the lumbar plexus. Despite the use of EMG monitoring, however, the authors have noted several cases of lumbar plexus injury with XLIF.
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 25th Annual Meeting / The Spine Journal 10 (2010) 1S–149S PURPOSE: To evaluate the anatomic and technical factors leading to lumbar plexus injury with XLIF as well as the prognosis for recovery. STUDY DESIGN/SETTING: See methods. PATIENT SAMPLE: The first 100 consecutive cases of XLIF performed by the authors with a minimum of 15 months follow-up. The mean age was 57.8 years (range 26 to 80 years). All but three patients also underwent either supplemental lateral plating and/or PSF with pedicle screw fixation. No lateral plates were used at the L4-5 level, however. The mean number of operated levels (XLIF) was 1.8 (range 1 to 6). OUTCOME MEASURES: See methods. METHODS: All patients were observed for neurologic complications, particularly quadriceps weakness as well as subsequent recovery. The factors leading to quadriceps weakness were assessed including any cases in which stimulation thresholds with EMG monitoring were 5 Ma or less. RESULTS: Three of the 100 total patients (3.0%) were noted to have significant quadriceps weakness lasting longer than 6 weeks that required the use of assistive devices for greater than two weeks. In all three the L4-5 level was included in the fusion, representing 3.8% of the 78 patients that included L4-5 as an operated level. In each of these patients, the L4-5 level was noted to be anatomically challenging, requiring aggressive table flexion to access the disc. Also, each of these patients had EMG stimulation thresholds #5 Ma during the approach, mandating anterior transpsoas penetration and thus posterior retraction of the bulk of the psoas muscle to access the disc. All three patients experienced sufficient recovery by 6 months such that assistive devices were no longer required for ambulation. CONCLUSIONS: XLIF is a safe alternative to other approaches for lumbar interbody reconstruction and fusion. It has a much lower risk of vascular injury as compared to traditional ALIF and virtually no risk of injury to the cauda equina as compared to PLIF & TLIF. There is, however, a risk of lumbar plexus injury that is somewhat unique to the transpsoas approach used in XLIF. XLIF carries a risk of lumbar plexus injury that is reduced, but not eliminated, by the use of EMG monitoring; with L45 being the most susceptible level. The authors hypothesize that the risk of lumbar injury is associated with a combination of compression of the lumbar plexus (resulting from posterior retraction) and lumbar plexus stretch from aggressive table flexion. Fortunately, the prognosis for recovery from this injury is excellent. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs. doi: 10.1016/j.spinee.2010.07.357
P82. Is Spinal Motion Limited by Contemporary Lumbosacral Orthoses? A Comparison of Three Braces John Hipp, PhD1, Tom Dibello, CO2, David Dice, MD1, Charles A. Reitman, MD1, Jacob Weinberg, MD1; 1Orthopedic Surgery, Baylor College of Medicine, Houston, TX, USA; 2Dynamic Orthotics and Prosthetics, LP, Houston, TX, USA BACKGROUND CONTEXT: External braces are frequently used to immobilize the lumbosacral spine. Three contemporary lumbosacral orthotic (LSO) designs include the Boston Overlap Brace (Boston BraceÔ), Boston Overlap Brace with a thigh extension, and the Gomez Pelvic Sacral (GPS) brace with a sacrococcygeal extension (Gomez Orthotics SystemÔ). These three brace designs may have different abilities to externally immobilize the lumbosacral spine. PURPOSE: To study the effect of each brace type on limiting motion in the lumbosacral spine. STUDY DESIGN/SETTING: Observational study. PATIENT SAMPLE: Twelve adult volunteers were recruited for this study. The average age was 30 years and the mean BMI was 24.5 kg/m2. The volunteers had no history of back pain or radiographic evidence of pathology in the lumbosacral spine. OUTCOME MEASURES: Intervertebral motion at L4-5 and L5-S1.
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METHODS: Volunteers were measured, fitted, and placed in each of the three brace types by a licensed orthotist for a minimum of 10 minutes. The thigh extension was set to allow motion from 0-30 degrees of hip flexion. Flexion and extension radiographs of the lumbar spine were obtained with each of the three braces. Intervertebral motion was measured from the flexion/extension radiographs using previously validated computer-assisted methods (QMAÔ, Medical Metrics, Inc). At each intervertebral level, measurements included change in anterior disc height, change in posterior disc height, rotation, and shear. This motion was compared to previous data of unbraced volunteers. RESULTS: There was significantly less motion at L4-L5 in the Boston Overlap Brace with a thigh extension compared to the Boston Overlap Brace alone (P50.03). There were no other significant differences, although there was a trend for less motion with the GPS brace compared to the Boston Overlap brace (P50.15). There were no significant differences in motion restriction between these braces at L5-S1 (P50.18). The intervertebral rotation and translation in these volunteers wearing a brace was within the 95% confidence intervals established for unbraced volunteers. CONCLUSIONS: Differences between these braces may be detected at L4-L5. However, in general, these orthoses do not significantly restrict intervertebral motion in the lumbosacral spine. Successful lumbosacral bracing may require further study. FDA DEVICE/DRUG STATUS: Boston Overlap Brace, Boston Overlap Brace with thigh extension, Gomez Pelvic Sacral (GPS) brace: Approved for this indication. doi: 10.1016/j.spinee.2010.07.358
P83. 2-Year Results from Four IDE Study Sites: CerviCoreÒ Intervertebral Disc vs. Fusion Jean-Jacques Abitbol, MD1, Joseph C. Maroon, MD2, Willie S. Edwards, MD3, Jeffrey S. Fischgrund, MD4; 1 California Spine, San Diego, CA, USA; 2Tri-State Neurosurgical Associates - UPMC, Pittsburgh, PA, USA; 3Pee Dee Spine Center, Florence, SC, USA; 4Michigan Orthopaedic Institute, Southfield, MI, USA BACKGROUND CONTEXT: The CerviCoreÒ Intervertebral Disc is intended to replace a single cervical intervertebral disc between C3 and C7 in skeletally mature patients, increase and maintain disc height, reduce upper extremity radicular symptoms, improve function, and permit movement of the treated spine segment. PURPOSE: This study compares the CerviCoreÒ Intervertebral Disc to the gold standard of ACDF, for single-level treatment of cervical radicular symptoms. STUDY DESIGN/SETTING: Data was collected from four of the CerviCoreÒ IDE study sites, which was a multi-center, prospective, randomized, controlled clinical trial conducted at 25 centers in the United States. PATIENT SAMPLE: At our four sites, data is available for: 49 CerviCoreÒ patients and 49 ACDF patients at baseline and 31 CerviCoreÒ and 26 ACDF patients at 2 years. OUTCOME MEASURES: Functionality was assessed with NDI and upper extremity pain was measured using worse arm (at pre-op) VAS. METHODS: Subjects who qualified were evaluated pre-operatively at 6 weeks, 3 months, 6 months, 12 months, and 24 months post-operatively. Complications and adverse events were evaluated over the course of the clinical trial. RESULTS: Within each treatment group, the mean NDI and Worse Arm VAS results were significantly different from pre-op at all visits up to 2 years (p!.0001). The mean NDI scores (CerviCoreÒ vs. fusion) were: 54 vs. 53 at pre-op. At 2 years, mean scores were 13 vs. 17. Differences between and within groups were not significant. The mean Worse Arm VAS scores were: 77 vs. 69 at pre-op and 16 vs. 17 at the 2 year follow-up. The difference between groups was significant at 6 weeks (p5.0483), where CerviCoreÒ group’s mean change from baseline was
All referenced figures and tables will be available at the Annual Meeting and will be included with the post-meeting online content.