- Email: [email protected]
P34. Does Vertebral Endplate Morphology Influence Clinical and Radiographic Outcomes in Lumbar Disc Arthroplasy? An Initial Assessment of a Novel Classification System of Lumbar Endplate Morphology
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Proceedings of the NASS 22nd Annual Meeting / The Spine Journal 7 (2007) 1S–163S
seen with MoM TDR’s is difficult to explain but may be a result of many variables including: test method, implant design, etc. Further evaluation will need to be performed to determine the exact reason for this particular finding. Finally, while volumetric wear is a common way to compare wear, density and particle size/number is required to gain information about the biologic impact of the wear. FDA DEVICE/DRUG STATUS: Maverick TDR: Investigational/ Not approved; Prodisc-L TDR: Approved for this indication.
degenerative lumbar scoliosis. Medical complications were most common. Those patients experiencing no complications had a slightly better clinical outcome, though not statistically significant. Careful patient selection and prompt managment of post-operative complications is essential. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs. doi: 10.1016/j.spinee.2007.07.249
doi: 10.1016/j.spinee.2007.07.248
P33. Complications Occuring in Patients Older than 70 Undergoing Surgical Management of Degenerative Lumbar Scoliosis Christopher Furey, MD1, Jung Yoo, MD2, Sanford Emery, MD3, Henry Bohlman, MD4; 1Case Western Reserve University, Cleveland, OH, USA; 2Oregon Health Sciences University, Portland, OR, USA; 3 Morgantown, WV, USA; 4Spine Institute, University Hospitals of Cleveland, Cleveland, OH, USA BACKGROUND CONTEXT: Surgical treatment of degenerative lumbar scoliosis is a challenging and complex undertaking. Patients are older and frequently have numerous medical co-morbidities. Surgeries are lengthy and with potential for serious complications. Appropriate selection of surgical patients is essential to successful outcomes. PURPOSE: To identify the nature, frequency, and effect on outcome of complications occurring in patients older than 70 years of age who have undergone posterior decompression and fusion for degenerative lumbar scoliosis. STUDY DESIGN/SETTING: A retrospective clinical and radiographic analysis. PATIENT SAMPLE: 67 consecutive patients greater than 70 years of age who underwent posterior decompression and fusion for the management of degenerative lumbar scoliosis. OUTCOME MEASURES: Oswestry Disability Index and a specific questionnaire evaluating relief of back and leg pain, satisfaction of pre-operative expectations, and willingness to repeat the procedure. Plain radiographs were routinely employed and CT scan when there was concern for non-union. METHODS: 67 consecutive patients greater than 70 years of age. 50 women and 17 men with an average age of 76 years (range: 70–87) were followed for an average of 6.7 years (range 2.0–17 years). All levels with stenosis were decompressed. All patients had posterolateral fusion with iliac crest autograft. 30 patients (45%) had pedicle screw fixation. RESULTS: Major complications occurred in 14 patients (20%). There was one death (1.4%) due to post-operative heart failure. 3 patients (4%) had major medical problems (2 myocardial infarction, 1 DVT). Deep space infections occurred in 4 patients (6%). One patient (1.4%) developed an epidural hematoma requiring emergent surgical evacuation. 4 patients (6%) developed adjacent level stenosis and 3 patients (4%) developed proximal junctional kyphosis. Risk factors for the development of medical problems included diabetes, smoking, and prior cardiac disease requiring intervention. Risk factors for the development of adjacent level stenosis and proximal junctional kyphosis included body mass index one standard deviation greater than normal and long segment fusion from L1 to L5. Use of pedicle screw instrumentation was not associated with a higher incidence of complications. At most recent follow-up, clinical satisfaction was excellent or good in 86% of patients who were complication-free and 80% who had experienced a complication. Oswestry Disability Index improved an average of 26 in patients with no complications and an average of 21 in those with a complication (pO.05) Achievement of pre-operative goals was obtained in 90% of patients who had no complications and 80% in those with a complication. Willingness to repeat the identical procedure was found in 94% of patients of patients with no complications and 86% of those with complications. CONCLUSIONS: Major complications occurred in 20% patients older than age 70 who underwent posterior decompression and fusion for
P34. Does Vertebral Endplate Morphology Influence Clinical and Radiographic Outcomes in Lumbar Disc Arthroplasy? An Initial Assessment of a Novel Classification System of Lumbar Endplate Morphology James Yue, MD1, Rudolf Bertagnoli, MD, PhD2, Jorge Jaramillo, MD3, Matthew Oetgen, MD1; 1Yale University, New Haven, CT, USA; 2 Straubing, Germany; 3Yale University School of Medicine, New Haven, CT, USA BACKGROUND CONTEXT: The influence of lumbar endplate morphology on the clinical and radiographic outcomes of lumbar disc arthroplasty has not been evaluated. A useful classification system should be reproducible, help guide operative decision making, enhance clinical and radiographic outcomes, and serve as a basis for comparison and discussion amongst arthroplasty clinicians. PURPOSE: To evaluate the influence of lumbar endplate morphology on clinical and radiographic outcomes of lumbar disc arthroplasty utilizing a novel classification system. STUDY DESIGN/SETTING: Prospective, non randomized longitudinal, minimum 2 year follow-up. PATIENT SAMPLE: This study consisted the evaluation of 80 patients (119 levels) who had been prospectively entered into a randomized FDA IDE clinical trial for the Prodisc lumbar artificial disc replacement. OUTCOME MEASURES: I. An intra and inter-observer analysis of a novel classification system. II, Outcome parameters included Oswestry, VAS, SF-36, and radiographic ROM. METHODS: The study was composed of 2 distinct parts. Part one consisted of the formulation of a novel vertebral endplate morphology classification system based upon extensive clinical experience and a review the lateral pre-operative radiographs of eighty patients (119 disc levels) who were part of a prospective clinical and radiographic outcome analysis. An intra and inter-observer analysis of the classification system was performed on the same eighty patients utilizing the classification system. Part two consisted of determining the usefulness in determining clinical and radiographic outcomes of the same eighty patients in terms of their classification type. Outcome parameters included Oswestry, VAS, SF-36, and radiographic ROM. In this study all patients underwent either single or bi-segmental total disc replacement utilizing the Prodisc-L prosthesis by the same surgeon at a single institution from Nov 2002 to February 2005. RESULTS: Part I: The initial review of the radiographs revealed 5 types of endplates as illustrated in Figure 1. Type I (n582 levels) is composed of flat endplates, Type II (n526) is composed of a posterior lip inhibiting posterior positioning of the implant, Type III (n55) includes a central concavity, Type IV (n54) includes an anterior sloping endplate, and TYPE V (n52) is a combination of Types II-IV. The intra-observer Kappa was 0.69 and the inter-observor Kappa was .61. Both of these Kappa values indicate ‘‘substantial’’ reproducibility (0-0.2 slight, 0.21–0.4 fair, 0.41-0.6 moderate, 0.61–0.8 substantial, 0.81-1 almost perfect). Part II Type one and type three had the largest decrease in pain and Oswestry score, the type 2 had the lowest reduction in pain and Oswestry score change. These differences were not statistically significant. Type II endplates without appropriate re-surfacing had the worst ROM (p!0.002). Subsidence was also higher in Type III cases (p5.12). CONCLUSIONS: In this study, we propose a lumbar endplate classification system to be used in the pre-operative assessment of patients undergoing lumbar disc arthroplasty. Our initial evaluation indicates that our classification is reproducible, may enhance clinical and radiographic
Proceedings of the NASS 22nd Annual Meeting / The Spine Journal 7 (2007) 1S–163S outcomes, may serve as a basis for comparison and discussion amongst arthroplasty clinicians, and serve as a possible exclusionary screening tool for disc arthroplasty. Special consideration should be given to Type II endplates to optimize proper positioning and functioning of an ADR implant. FDA DEVICE/DRUG STATUS: Prodisc: Approved for this indication.
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subluxations. In our limited number of cervical TDR patients who were involved with contact-vigorous activities, no implant complications occurred in either implant type. FDA DEVICE/DRUG STATUS: Prodisc: Approved for this indication; Charite´: Approved for this indication; PCM cervical ADR: Investigational/ Not approved.
doi: 10.1016/j.spinee.2007.07.250 doi: 10.1016/j.spinee.2007.07.251 P35. Consequences of Athletic Activity in the Lumbar and Cervical Total Disc Replacement Patient: A Multi-center Non-randomized Prospective Study James Yue, MD1, Matthew Scott-Young, MD2, Rudolf Bertganoli, MD, PhD3, Jorge Jaramillo4, Matthew McRae, MD5, Mark McRae, MD5; 1Yale University, New Haven, CT, USA; 2Southport, Queensland, Australia; 3St. Elizabeth Klinikum, Straubing, Germany; 4Yale University School of Medicine, New Haven, CT, USA; 5New Haven, CT, USA BACKGROUND CONTEXT: The influence of athletic activity on the clinical and radiographic outcomes of lumbar disc arthroplasty has not been evaluated to the best of our knowledge. PURPOSE: To evaluate the consequences of differing levels of athletic activity on the clinical and radiographic outcomes of lumbar and cervical disc arthroplasty. STUDY DESIGN/SETTING: Prospective, non randomized, longitudinal, multi-center, minimum 2 year follow-up. PATIENT SAMPLE: Patients of 3 major arthroplasty centers in 3 continents (North America, Europe, and Australia). OUTCOME MEASURES: Oswestry, VAS, Radiographic imaging. METHODS: The prospective records of 3 major arthroplasty centers in 3 continents (North America, Europe, and Australia) were analyzed for the pre-operative and post-operative athletic activities of lumbar and cervical total disc replacement (TDR) patients. Athletic activities prior to the onset of spinal injury, after the onset of spinal injury, and post-TDR surgery were assessed. Activities were classified professional vs. amateur as well as into contact/vigorous, moderate, and light in terms of effect on involved spinal segments. Complications were assessed both radiographically as well as clinically. RESULTS: Lumbar: A total of 1003 lumbar patients full-filled all followup criteria including 2 year follow-up. There were 255 Charite´ and 748 Prodisc prostheses. Of the Charite´ discs 56 participated in sports prior to spine injury. Following TDR, 48/56 participated in athletic activities (22 contact/vigorous, 11 moderate, and 15 light). Five were professional and 43 were amateur. There were no implant complications. Five patients complained of radiculopathy symptoms during participation. No implant related complications occurred during any type of activity. Of the Prodisc cases 172 participated in sports prior to spine injury. Following TDR, 158/172 participated in athletic activities (34 contact/vigorous, 27 moderate, and 97 light). Eight were professional and 150 were amateur. Seven patients complained of radiculopathy symptoms during participation. Three L5/S1 subluxations occurred with heavy weight lifting and 1 implant loosening occurred after a bike injury. Cervical: A total of 210 cervical patients full-filled all follow-up criteria including 2 year follow-up. There were 45 PCM discs and 167 Prodiscs. Of the PCM discs 18 participated in sports prior to spine injury. Following TDR, 8/18 participated in athletic activities (3 contact/vigorous, 5 moderate, and 0 light). Three were professional and 5 were amateur. There were no implant complications. No implant related complications occurred during any type of activity. Of the Prodisc cases 138 participated in sports prior to spine injury. Following TDR, 87/138 participated in athletic activities (16 contact/vigorous, 47 moderate, and 24 light). None were professional. No implant complications occurred. CONCLUSIONS: Athletic activities of varying degrees appear to be well tolerated following both cervical and lumbar TDR surgery in single and multi-level cases. Contact-vigorous athletic activities do not appear to result in high levels of clinical or radiographic complications in the lumbar TDR patients except for heavy weight lifting activities in patients who have undergone L5/S1 Prodisc surgery in which we experienced 3 PE
P36. An Analysis of Collagen Cross Linking via Nonenzymatic Glycation in the Intervertebral Disc Alok Sharan, MD1, Simon Tang2, Martin Quirno, MD3, Deepak Vashishth, PhD4, Tom Errico, MD3; 1Montefiore Medical Center, Bronx, NY, USA; 2 RPI, Troy, NY, USA; 3HJD-NYU, NY, NY, USA; 4RPI, Rensselaer, NY, USA BACKGROUND CONTEXT: Modification of proteins through the process of Nonenzymatic glycation (NEG) occurs through the normal aging process. It has been hypothesized that areas that demonstrate a decreased turnover of these proteins accumulate these Advanced Glycation Endproducts (AGEs) which results in a stiffer collagen network. PURPOSE: The purpose of this study was to analyze the content of AGE products in the intervertebral disc and compare it to disc height, a measure of disc degeneration. In addition, the level of browning was analyzed using PhotoshopÓ, and compared to NEG levels to help quantify this degenerative process. STUDY DESIGN/SETTING: Intervertebral discs were obtained from patients undergoing lumbar interbody fusion. PATIENT SAMPLE: 59 intervertebral discs were removed from 34 patients (6 cervical, 13 thoracic, and 40 lumbar). OUTCOME MEASURES: The height of the discs as well as the NEG content of the discs were measured. METHODS: Discs were stored in normal saline and analyzed for NEG content. The intervertebral discs were digested with 6.0 M HCl (24 hours, 110 C) capped using Teflon-lined borosilicate bottles. NEG content was determined using fluorescence readings at 370/440 nm and normalized to a quinine sulfate standard. Collagen content was determined using a hydroxyproline assay, determined by the absorbance of the lysates at 570nm. Disc height measurements were made from a standing lateral xray of the lumbar spine. Discs were excluded if proper xray measurements could not be completed. In addition discs from patients with scoliosis were excluded due to the difficulty in measuring the disc heights. A total of 14 discs and corresponding xrays were available for analysis. Disc height measurements were obtained by measuring the anterior and posterior intervertebral distances and averaging these two points. Quantification of the color of the discs was made using Adobe PhotoshopÓ. Digital photos were taken of 23 intervertebral discs. Using the eye dropper function, the RGB (red, green, brown) values were recorded. A linear regression model was computed between individual RGB values and the corresponding NEG level. RESULTS: A significant correlation was found between decreasing disc height and NEG levels (p!0.03)). In quantifying the coloration of the disc, correlations were obtained between the RBG parameters and NEG levels. A significant correlation was only obtained between the Blue parameter and NEG level (Table 1). CONCLUSIONS: In this study, our results reveal a strong correlation (P!0.03) between decreasing disc heights and increased NEG levels. It is hypothesized that the increased levels of NEG content results in a stiffer collagen matrix which results in a decreased ability of the annulus fibrosus to withstand normal spinal loads and an increased rate of degeneration. Degenerated discs have been demonstrated to contain an increased amount of brown pigment (3). Our study provides a quantitative assessment of this color change using the RGB values obtained from Adobe PhotoshopÓ,. Our results reveal that the Blue parameter correlates strongly with NEG levels. In a standard color palette, as the red and green values are fixed, the level of blue present contributes to brown hue of a color. Based on our data we provide a Grading Scheme of the ‘‘browning’’ seen with intervertebral discs that corresponds with NEG levels.
Proceedings of the NASS 22nd Annual Meeting / The Spine Journal 7 (2007) 1S–163S
seen with MoM TDR’s is difficult to explain but may be a result of many variables including: test method, implant design, etc. Further evaluation will need to be performed to determine the exact reason for this particular finding. Finally, while volumetric wear is a common way to compare wear, density and particle size/number is required to gain information about the biologic impact of the wear. FDA DEVICE/DRUG STATUS: Maverick TDR: Investigational/ Not approved; Prodisc-L TDR: Approved for this indication.
degenerative lumbar scoliosis. Medical complications were most common. Those patients experiencing no complications had a slightly better clinical outcome, though not statistically significant. Careful patient selection and prompt managment of post-operative complications is essential. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs. doi: 10.1016/j.spinee.2007.07.249
doi: 10.1016/j.spinee.2007.07.248
P33. Complications Occuring in Patients Older than 70 Undergoing Surgical Management of Degenerative Lumbar Scoliosis Christopher Furey, MD1, Jung Yoo, MD2, Sanford Emery, MD3, Henry Bohlman, MD4; 1Case Western Reserve University, Cleveland, OH, USA; 2Oregon Health Sciences University, Portland, OR, USA; 3 Morgantown, WV, USA; 4Spine Institute, University Hospitals of Cleveland, Cleveland, OH, USA BACKGROUND CONTEXT: Surgical treatment of degenerative lumbar scoliosis is a challenging and complex undertaking. Patients are older and frequently have numerous medical co-morbidities. Surgeries are lengthy and with potential for serious complications. Appropriate selection of surgical patients is essential to successful outcomes. PURPOSE: To identify the nature, frequency, and effect on outcome of complications occurring in patients older than 70 years of age who have undergone posterior decompression and fusion for degenerative lumbar scoliosis. STUDY DESIGN/SETTING: A retrospective clinical and radiographic analysis. PATIENT SAMPLE: 67 consecutive patients greater than 70 years of age who underwent posterior decompression and fusion for the management of degenerative lumbar scoliosis. OUTCOME MEASURES: Oswestry Disability Index and a specific questionnaire evaluating relief of back and leg pain, satisfaction of pre-operative expectations, and willingness to repeat the procedure. Plain radiographs were routinely employed and CT scan when there was concern for non-union. METHODS: 67 consecutive patients greater than 70 years of age. 50 women and 17 men with an average age of 76 years (range: 70–87) were followed for an average of 6.7 years (range 2.0–17 years). All levels with stenosis were decompressed. All patients had posterolateral fusion with iliac crest autograft. 30 patients (45%) had pedicle screw fixation. RESULTS: Major complications occurred in 14 patients (20%). There was one death (1.4%) due to post-operative heart failure. 3 patients (4%) had major medical problems (2 myocardial infarction, 1 DVT). Deep space infections occurred in 4 patients (6%). One patient (1.4%) developed an epidural hematoma requiring emergent surgical evacuation. 4 patients (6%) developed adjacent level stenosis and 3 patients (4%) developed proximal junctional kyphosis. Risk factors for the development of medical problems included diabetes, smoking, and prior cardiac disease requiring intervention. Risk factors for the development of adjacent level stenosis and proximal junctional kyphosis included body mass index one standard deviation greater than normal and long segment fusion from L1 to L5. Use of pedicle screw instrumentation was not associated with a higher incidence of complications. At most recent follow-up, clinical satisfaction was excellent or good in 86% of patients who were complication-free and 80% who had experienced a complication. Oswestry Disability Index improved an average of 26 in patients with no complications and an average of 21 in those with a complication (pO.05) Achievement of pre-operative goals was obtained in 90% of patients who had no complications and 80% in those with a complication. Willingness to repeat the identical procedure was found in 94% of patients of patients with no complications and 86% of those with complications. CONCLUSIONS: Major complications occurred in 20% patients older than age 70 who underwent posterior decompression and fusion for
P34. Does Vertebral Endplate Morphology Influence Clinical and Radiographic Outcomes in Lumbar Disc Arthroplasy? An Initial Assessment of a Novel Classification System of Lumbar Endplate Morphology James Yue, MD1, Rudolf Bertagnoli, MD, PhD2, Jorge Jaramillo, MD3, Matthew Oetgen, MD1; 1Yale University, New Haven, CT, USA; 2 Straubing, Germany; 3Yale University School of Medicine, New Haven, CT, USA BACKGROUND CONTEXT: The influence of lumbar endplate morphology on the clinical and radiographic outcomes of lumbar disc arthroplasty has not been evaluated. A useful classification system should be reproducible, help guide operative decision making, enhance clinical and radiographic outcomes, and serve as a basis for comparison and discussion amongst arthroplasty clinicians. PURPOSE: To evaluate the influence of lumbar endplate morphology on clinical and radiographic outcomes of lumbar disc arthroplasty utilizing a novel classification system. STUDY DESIGN/SETTING: Prospective, non randomized longitudinal, minimum 2 year follow-up. PATIENT SAMPLE: This study consisted the evaluation of 80 patients (119 levels) who had been prospectively entered into a randomized FDA IDE clinical trial for the Prodisc lumbar artificial disc replacement. OUTCOME MEASURES: I. An intra and inter-observer analysis of a novel classification system. II, Outcome parameters included Oswestry, VAS, SF-36, and radiographic ROM. METHODS: The study was composed of 2 distinct parts. Part one consisted of the formulation of a novel vertebral endplate morphology classification system based upon extensive clinical experience and a review the lateral pre-operative radiographs of eighty patients (119 disc levels) who were part of a prospective clinical and radiographic outcome analysis. An intra and inter-observer analysis of the classification system was performed on the same eighty patients utilizing the classification system. Part two consisted of determining the usefulness in determining clinical and radiographic outcomes of the same eighty patients in terms of their classification type. Outcome parameters included Oswestry, VAS, SF-36, and radiographic ROM. In this study all patients underwent either single or bi-segmental total disc replacement utilizing the Prodisc-L prosthesis by the same surgeon at a single institution from Nov 2002 to February 2005. RESULTS: Part I: The initial review of the radiographs revealed 5 types of endplates as illustrated in Figure 1. Type I (n582 levels) is composed of flat endplates, Type II (n526) is composed of a posterior lip inhibiting posterior positioning of the implant, Type III (n55) includes a central concavity, Type IV (n54) includes an anterior sloping endplate, and TYPE V (n52) is a combination of Types II-IV. The intra-observer Kappa was 0.69 and the inter-observor Kappa was .61. Both of these Kappa values indicate ‘‘substantial’’ reproducibility (0-0.2 slight, 0.21–0.4 fair, 0.41-0.6 moderate, 0.61–0.8 substantial, 0.81-1 almost perfect). Part II Type one and type three had the largest decrease in pain and Oswestry score, the type 2 had the lowest reduction in pain and Oswestry score change. These differences were not statistically significant. Type II endplates without appropriate re-surfacing had the worst ROM (p!0.002). Subsidence was also higher in Type III cases (p5.12). CONCLUSIONS: In this study, we propose a lumbar endplate classification system to be used in the pre-operative assessment of patients undergoing lumbar disc arthroplasty. Our initial evaluation indicates that our classification is reproducible, may enhance clinical and radiographic
Proceedings of the NASS 22nd Annual Meeting / The Spine Journal 7 (2007) 1S–163S outcomes, may serve as a basis for comparison and discussion amongst arthroplasty clinicians, and serve as a possible exclusionary screening tool for disc arthroplasty. Special consideration should be given to Type II endplates to optimize proper positioning and functioning of an ADR implant. FDA DEVICE/DRUG STATUS: Prodisc: Approved for this indication.
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subluxations. In our limited number of cervical TDR patients who were involved with contact-vigorous activities, no implant complications occurred in either implant type. FDA DEVICE/DRUG STATUS: Prodisc: Approved for this indication; Charite´: Approved for this indication; PCM cervical ADR: Investigational/ Not approved.
doi: 10.1016/j.spinee.2007.07.250 doi: 10.1016/j.spinee.2007.07.251 P35. Consequences of Athletic Activity in the Lumbar and Cervical Total Disc Replacement Patient: A Multi-center Non-randomized Prospective Study James Yue, MD1, Matthew Scott-Young, MD2, Rudolf Bertganoli, MD, PhD3, Jorge Jaramillo4, Matthew McRae, MD5, Mark McRae, MD5; 1Yale University, New Haven, CT, USA; 2Southport, Queensland, Australia; 3St. Elizabeth Klinikum, Straubing, Germany; 4Yale University School of Medicine, New Haven, CT, USA; 5New Haven, CT, USA BACKGROUND CONTEXT: The influence of athletic activity on the clinical and radiographic outcomes of lumbar disc arthroplasty has not been evaluated to the best of our knowledge. PURPOSE: To evaluate the consequences of differing levels of athletic activity on the clinical and radiographic outcomes of lumbar and cervical disc arthroplasty. STUDY DESIGN/SETTING: Prospective, non randomized, longitudinal, multi-center, minimum 2 year follow-up. PATIENT SAMPLE: Patients of 3 major arthroplasty centers in 3 continents (North America, Europe, and Australia). OUTCOME MEASURES: Oswestry, VAS, Radiographic imaging. METHODS: The prospective records of 3 major arthroplasty centers in 3 continents (North America, Europe, and Australia) were analyzed for the pre-operative and post-operative athletic activities of lumbar and cervical total disc replacement (TDR) patients. Athletic activities prior to the onset of spinal injury, after the onset of spinal injury, and post-TDR surgery were assessed. Activities were classified professional vs. amateur as well as into contact/vigorous, moderate, and light in terms of effect on involved spinal segments. Complications were assessed both radiographically as well as clinically. RESULTS: Lumbar: A total of 1003 lumbar patients full-filled all followup criteria including 2 year follow-up. There were 255 Charite´ and 748 Prodisc prostheses. Of the Charite´ discs 56 participated in sports prior to spine injury. Following TDR, 48/56 participated in athletic activities (22 contact/vigorous, 11 moderate, and 15 light). Five were professional and 43 were amateur. There were no implant complications. Five patients complained of radiculopathy symptoms during participation. No implant related complications occurred during any type of activity. Of the Prodisc cases 172 participated in sports prior to spine injury. Following TDR, 158/172 participated in athletic activities (34 contact/vigorous, 27 moderate, and 97 light). Eight were professional and 150 were amateur. Seven patients complained of radiculopathy symptoms during participation. Three L5/S1 subluxations occurred with heavy weight lifting and 1 implant loosening occurred after a bike injury. Cervical: A total of 210 cervical patients full-filled all follow-up criteria including 2 year follow-up. There were 45 PCM discs and 167 Prodiscs. Of the PCM discs 18 participated in sports prior to spine injury. Following TDR, 8/18 participated in athletic activities (3 contact/vigorous, 5 moderate, and 0 light). Three were professional and 5 were amateur. There were no implant complications. No implant related complications occurred during any type of activity. Of the Prodisc cases 138 participated in sports prior to spine injury. Following TDR, 87/138 participated in athletic activities (16 contact/vigorous, 47 moderate, and 24 light). None were professional. No implant complications occurred. CONCLUSIONS: Athletic activities of varying degrees appear to be well tolerated following both cervical and lumbar TDR surgery in single and multi-level cases. Contact-vigorous athletic activities do not appear to result in high levels of clinical or radiographic complications in the lumbar TDR patients except for heavy weight lifting activities in patients who have undergone L5/S1 Prodisc surgery in which we experienced 3 PE
P36. An Analysis of Collagen Cross Linking via Nonenzymatic Glycation in the Intervertebral Disc Alok Sharan, MD1, Simon Tang2, Martin Quirno, MD3, Deepak Vashishth, PhD4, Tom Errico, MD3; 1Montefiore Medical Center, Bronx, NY, USA; 2 RPI, Troy, NY, USA; 3HJD-NYU, NY, NY, USA; 4RPI, Rensselaer, NY, USA BACKGROUND CONTEXT: Modification of proteins through the process of Nonenzymatic glycation (NEG) occurs through the normal aging process. It has been hypothesized that areas that demonstrate a decreased turnover of these proteins accumulate these Advanced Glycation Endproducts (AGEs) which results in a stiffer collagen network. PURPOSE: The purpose of this study was to analyze the content of AGE products in the intervertebral disc and compare it to disc height, a measure of disc degeneration. In addition, the level of browning was analyzed using PhotoshopÓ, and compared to NEG levels to help quantify this degenerative process. STUDY DESIGN/SETTING: Intervertebral discs were obtained from patients undergoing lumbar interbody fusion. PATIENT SAMPLE: 59 intervertebral discs were removed from 34 patients (6 cervical, 13 thoracic, and 40 lumbar). OUTCOME MEASURES: The height of the discs as well as the NEG content of the discs were measured. METHODS: Discs were stored in normal saline and analyzed for NEG content. The intervertebral discs were digested with 6.0 M HCl (24 hours, 110 C) capped using Teflon-lined borosilicate bottles. NEG content was determined using fluorescence readings at 370/440 nm and normalized to a quinine sulfate standard. Collagen content was determined using a hydroxyproline assay, determined by the absorbance of the lysates at 570nm. Disc height measurements were made from a standing lateral xray of the lumbar spine. Discs were excluded if proper xray measurements could not be completed. In addition discs from patients with scoliosis were excluded due to the difficulty in measuring the disc heights. A total of 14 discs and corresponding xrays were available for analysis. Disc height measurements were obtained by measuring the anterior and posterior intervertebral distances and averaging these two points. Quantification of the color of the discs was made using Adobe PhotoshopÓ. Digital photos were taken of 23 intervertebral discs. Using the eye dropper function, the RGB (red, green, brown) values were recorded. A linear regression model was computed between individual RGB values and the corresponding NEG level. RESULTS: A significant correlation was found between decreasing disc height and NEG levels (p!0.03)). In quantifying the coloration of the disc, correlations were obtained between the RBG parameters and NEG levels. A significant correlation was only obtained between the Blue parameter and NEG level (Table 1). CONCLUSIONS: In this study, our results reveal a strong correlation (P!0.03) between decreasing disc heights and increased NEG levels. It is hypothesized that the increased levels of NEG content results in a stiffer collagen matrix which results in a decreased ability of the annulus fibrosus to withstand normal spinal loads and an increased rate of degeneration. Degenerated discs have been demonstrated to contain an increased amount of brown pigment (3). Our study provides a quantitative assessment of this color change using the RGB values obtained from Adobe PhotoshopÓ,. Our results reveal that the Blue parameter correlates strongly with NEG levels. In a standard color palette, as the red and green values are fixed, the level of blue present contributes to brown hue of a color. Based on our data we provide a Grading Scheme of the ‘‘browning’’ seen with intervertebral discs that corresponds with NEG levels.