- Email: [email protected]
P66. Segmental Contribution Towards Total Lumbar Range of Motion in Disc Replacement and Fusions
Proceedings of the NASS 22nd Annual Meeting / The Spine Journal 7 (2007) 1S–163S P65. Tandem Stenosis in a Cadaveric Population Michael Lee, MD1, Ryan Garcia, MD2, Ezequiel Cassinelli, MD2, Christopher Furey, MD2, K. Daniel Riew, MD3; 1Rush University Medical Center, Chicago, IL, USA; 2Case Western Reserve University, Cleveland, OH, USA; 3Washington University in St. Louis, St Louis, MO, USA BACKGROUND CONTEXT: Concurrent lumbar and cervical stenosis or tandem stenosis was first described by Teng and Papatheodorou in 1964. The patient may present with a combination of neurogenic claudication and radiculomyelopathic symptoms. Initially, one set of symptoms may predominate, and the second area stenosis may not become evident until treatment of the primary problem. The purpose of this study was to determine the prevalence of tandem stenosis in an collection of adult anatomic cadavers, and to determine the positive predictive value of one area of stenosis for the other (lumbar and cervical). PURPOSE: The purpose of this study was to determine the incidence of tandem stenosis in a cadaveric population, and to determine how often the presence of stenosis in the one area of the spine predicts for stenosis in another area of the spine. STUDY DESIGN/SETTING: Ninety four adult skeletal specimens of the cervical spine were obtained from the Hamann Todd Collection in the Cleveland Museum of Natural History. Anatomic measurements were obtained in the lumbar and cervical spine of these adult specimens. PATIENT SAMPLE: No patients used in this study. OUTCOME MEASURES: Outcome measures consisted of direct measurements from cadaveric specimens. METHODS: Ninety four adult skeletal specimens of the cervical spine were obtained from the Hamann Todd Collection in the Cleveland Museum of Natural History. Using digital calipers and Image J software(NIH.com), the distance from the posterior most aspect of the vertebral body to the anterior most aspect of the spinolaminar structure was measured and recorded for each specimen at every level from C3 to C7 and from L1 to L5. In the present study, stenosis was defined as a canal diameter of less than 12 mm in the cervical and lumbar spine. RESULTS: The average AP canal diameter for all lumbar specimens was 15.58 mm (sd 2.08 mm) ranging from 10.29 to 20.66 mm. For the cervical spine, the average AP canal diameter was 14.08 mm (sd 1.52 mm). These ranged from 9.00 to 18.75 mm. 15% of people had at least one level of cervical stenosis less than 12 mm. Twenty one percent of people had at least one level of lumbar stenosis of less than 12 mm. Five percent of all people had at least one level of lumbar and cervical stenosis. The positive predictive value of lumbar stenosis as an indicator of cervical stenosis was found to be 25%. Conversely, the positive predictive value of cervical stenosis as an indicator for the presence of lumbar stenosis was 35% CONCLUSIONS: Tandem Stenosis appears to occur commonly in this anatomic study. Given that these specimens do not have any soft tissues, which can decrease the canals further, it is likely that the presence of stenosis is higher than our findings. Bearing this caveat in mind, our data suggest that the presence of cervical or lumbar stenosis appears to predict for the other at least 25-35% of the time. In the treatment of stenosis in the cervical or lumbar spine, the presence of tandem stenosis should be considered. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs. doi: 10.1016/j.spinee.2007.07.271
P66. Segmental Contribution Towards Total Lumbar Range of Motion in Disc Replacement and Fusions Joshua D. Auerbach, MD1, Kristofer Jones, BA2, Richard A. Balderston, MD3; 1The University of Pennsylvania, Philadelphia, PA, USA; 2The University of Pennsylvania School of Medicine, PA, USA; 33B Orthopaedics, Pennsylvania Hospital, Philadelphia, PA, USA BACKGROUND CONTEXT: Lumbar total disc replacement (TDR) enables maintenance of motion at the operative level which theoretically reduces stresses at the adjacent level, and possibly, the risk for subsequent adjacent segment degeneration. Although biomechanical studies have
113S
demonstrated reduced intradiscal pressures and more normal lumbar motion profiles at the proximal adjacent level with TDR compared with fusion, the impact on segmental contribution towards total lumbar range of motion (TLROM5L1-S1) following TDR or fusion has not yet been studied. PURPOSE: We hypothesize that TDR imparts a more evenly distributed total lumbar ROM profile and that fusions increase the segmental contribution towards TLROM at multiple adjacent levels. STUDY DESIGN/SETTING: Retrospective radiographic review of consecutive patients enrolled in a prospective study PATIENT SAMPLE: Consecutive patients enrolled in a prospective, randomized IDE trial comparing lumbar TDR (ProDisc-L) with circumferential fusion for 1-level degenerative disc disease OUTCOME MEASURES: Cobb angle measurements and ROM values at each level from L1-S1, and total lumbar motion from L1-S1 METHODS: Flexion-extension radiographs collected from all 1-level patients with complete datasets were evaluated pre-operatively and at 24 months post-operatively. Radiographic measurements were performed by an independent contractor using custom digital software to generate Cobb and ROM values at each level from L1-S1, and total lumbar motion from L1-S1. RESULTS: There were 228 patients in the ProDisc-L group, and 63 patients in the circumferential fusion group. Pre-operatively, there was no difference in TLROM (L1-S1) between the groups (TDR: 35 vs F: 36 , p50.9). Post-operatively, fusions had significantly less TLROM (TDR: 38 vs F: 29 , p50.0005). At the operative level, TDR had significantly higher contribution (percentage of total) towards total lumbar ROM (TDR: 16% vs F: 2%, p!0.0001). At the proximal adjacent level, fusions had significantly more contribution to TLROM than TDR (TDR: 19% vs F: 25%, p50.020). The contribution towards TLROM was also greater in fusions at the 2nd adjacent level (TDR: 20% vs F: 24%, p50.1), 3rd adjacent level (TDR: 23% vs F: 29%, p50.005), and at the 4th adjacent level (TDR: 21% vs F: 31%, p50.06). Comparing the pre-operative and post-operative contribution from adjacent levels to TLROM within the fusion group revealed an increase in all levels which was most significant in the 1st adjacent level (p50.0004). In TDR, there was no difference from pre-operative to post-operative in the adjacent level contribution to TLROM. CONCLUSIONS: Fusion patients had significantly lower total lumbar ROM at 24 months post-operatively compared to TDR patients. More importantly, compensation for the loss of motion was seen adjacently with significantly higher segmental contribution from successive adjacent levels. The contribution from the adjacent levels to total lumbar ROM in TDR, however, remained unchanged from the pre-operative condition, suggesting maintenance of a physiologic distribution of lumbar ROM. If DDD is a mechanical disease, these data suggest a reduced risk for developing adjacent segment degeneration and maintenance of more normal global lumbar mobility in TDR patients compared to fusion patients. FDA DEVICE/DRUG STATUS: ProDisc-L, Synthes Spine, West Chester, PA: Approved for this indication. doi: 10.1016/j.spinee.2007.07.272
P67. Clinical and Radiological Indications of Surgical Repair for Symptomatic Lumbar Spondylolysis Gyoung Beom Kim, MD, PhD1, Ho Suk Jang, MD1, Byeong Wook Hwang, MD, PhD1, Sang Jin Lee, MD, PhD1, Won Gyu Choi, MD, PhD1, SangHo Lee, MD, PhD1; 1Busan Wooridul Spine Hospital, Busan, South Korea BACKGROUND CONTEXT: Lumbar spondylolysis is a defect in the pars interarticularis and can cause back pain. Recently, segmental pedicle screw-laminar hook fixation was reported as a non-fusion stabilization for preservation of motion segment and anatomic continuity. However, its surgical indication has not been clearly determined. PURPOSE: The purpose of this study is to evaluate the clinical and radiological indications of pedicle screw-laminar hook fixation with bone graft for symptomatic lumbar spondylolysis.
P66. Segmental Contribution Towards Total Lumbar Range of Motion in Disc Replacement and Fusions Joshua D. Auerbach, MD1, Kristofer Jones, BA2, Richard A. Balderston, MD3; 1The University of Pennsylvania, Philadelphia, PA, USA; 2The University of Pennsylvania School of Medicine, PA, USA; 33B Orthopaedics, Pennsylvania Hospital, Philadelphia, PA, USA BACKGROUND CONTEXT: Lumbar total disc replacement (TDR) enables maintenance of motion at the operative level which theoretically reduces stresses at the adjacent level, and possibly, the risk for subsequent adjacent segment degeneration. Although biomechanical studies have
113S
demonstrated reduced intradiscal pressures and more normal lumbar motion profiles at the proximal adjacent level with TDR compared with fusion, the impact on segmental contribution towards total lumbar range of motion (TLROM5L1-S1) following TDR or fusion has not yet been studied. PURPOSE: We hypothesize that TDR imparts a more evenly distributed total lumbar ROM profile and that fusions increase the segmental contribution towards TLROM at multiple adjacent levels. STUDY DESIGN/SETTING: Retrospective radiographic review of consecutive patients enrolled in a prospective study PATIENT SAMPLE: Consecutive patients enrolled in a prospective, randomized IDE trial comparing lumbar TDR (ProDisc-L) with circumferential fusion for 1-level degenerative disc disease OUTCOME MEASURES: Cobb angle measurements and ROM values at each level from L1-S1, and total lumbar motion from L1-S1 METHODS: Flexion-extension radiographs collected from all 1-level patients with complete datasets were evaluated pre-operatively and at 24 months post-operatively. Radiographic measurements were performed by an independent contractor using custom digital software to generate Cobb and ROM values at each level from L1-S1, and total lumbar motion from L1-S1. RESULTS: There were 228 patients in the ProDisc-L group, and 63 patients in the circumferential fusion group. Pre-operatively, there was no difference in TLROM (L1-S1) between the groups (TDR: 35 vs F: 36 , p50.9). Post-operatively, fusions had significantly less TLROM (TDR: 38 vs F: 29 , p50.0005). At the operative level, TDR had significantly higher contribution (percentage of total) towards total lumbar ROM (TDR: 16% vs F: 2%, p!0.0001). At the proximal adjacent level, fusions had significantly more contribution to TLROM than TDR (TDR: 19% vs F: 25%, p50.020). The contribution towards TLROM was also greater in fusions at the 2nd adjacent level (TDR: 20% vs F: 24%, p50.1), 3rd adjacent level (TDR: 23% vs F: 29%, p50.005), and at the 4th adjacent level (TDR: 21% vs F: 31%, p50.06). Comparing the pre-operative and post-operative contribution from adjacent levels to TLROM within the fusion group revealed an increase in all levels which was most significant in the 1st adjacent level (p50.0004). In TDR, there was no difference from pre-operative to post-operative in the adjacent level contribution to TLROM. CONCLUSIONS: Fusion patients had significantly lower total lumbar ROM at 24 months post-operatively compared to TDR patients. More importantly, compensation for the loss of motion was seen adjacently with significantly higher segmental contribution from successive adjacent levels. The contribution from the adjacent levels to total lumbar ROM in TDR, however, remained unchanged from the pre-operative condition, suggesting maintenance of a physiologic distribution of lumbar ROM. If DDD is a mechanical disease, these data suggest a reduced risk for developing adjacent segment degeneration and maintenance of more normal global lumbar mobility in TDR patients compared to fusion patients. FDA DEVICE/DRUG STATUS: ProDisc-L, Synthes Spine, West Chester, PA: Approved for this indication. doi: 10.1016/j.spinee.2007.07.272
P67. Clinical and Radiological Indications of Surgical Repair for Symptomatic Lumbar Spondylolysis Gyoung Beom Kim, MD, PhD1, Ho Suk Jang, MD1, Byeong Wook Hwang, MD, PhD1, Sang Jin Lee, MD, PhD1, Won Gyu Choi, MD, PhD1, SangHo Lee, MD, PhD1; 1Busan Wooridul Spine Hospital, Busan, South Korea BACKGROUND CONTEXT: Lumbar spondylolysis is a defect in the pars interarticularis and can cause back pain. Recently, segmental pedicle screw-laminar hook fixation was reported as a non-fusion stabilization for preservation of motion segment and anatomic continuity. However, its surgical indication has not been clearly determined. PURPOSE: The purpose of this study is to evaluate the clinical and radiological indications of pedicle screw-laminar hook fixation with bone graft for symptomatic lumbar spondylolysis.