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Long-Term Follow-Up Results Following Laminectomy for Cervical Ossification of the Posterior Longitudinal Ligament
Proceedings of the NASS 27th Annual Meeting / The Spine Journal 12 (2012) 99S–165S CONCLUSIONS: Until now, there has been no way to accurately assess during surgery whether the nerve threshold has been altered by surgical decompression. MMG offers the potential to do this and may represent a promising technique for assessing nerve damage and nerve decompression during surgery.Based on the information from this study, MMG may have value as a means to assess adequacy of decompression whenever direct observation is not possible, such as in MIS procedures. Further studies will be needed. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs. http://dx.doi.org/10.1016/j.spinee.2012.08.341
P68. Long-Term Follow-Up Results Following Laminectomy for Cervical Ossification of the Posterior Longitudinal Ligament Soo Eon Lee, MD1, Chun Kee Chung, MD2, Tae-Ahn Jahng, MD, PhD2; 1 Seoul, South Korea; 2Seoul National University Hospital, Seoul, South Korea BACKGROUND CONTEXT: Laminectomy is an effective surgical technique for the treatment of cervical OPLL along multilevel. However, postoperative kyphosis and probable neurological deterioration have been frequently reported after laminectomy. PURPOSE: We analyzed the changes in the cervical curvature after laminectomy and subsequent changes in neurological status in treating ossification of the posterior longitudinal ligament (OPLL) of the cervical spine. STUDY DESIGN/SETTING: Retrospective study. PATIENT SAMPLE: The authors reviewed the 38 patients who underwent cervical laminectomy between 1999 and 2003. OUTCOME MEASURES: The preoperative symptoms, Japanese Orthopedic Association (JOA) score and recovery rate was reviewed using medical records. The OPLL type was classified to continous, segmental, mixed and local type. The cervical global angle and range of motion (ROM) was measured by posterior tangent method at preoperation and the last follow-up. METHODS: According to the cervical global angle, the cervical curvature was distributed into three types; lordosis, straight, and kyphosis. The change in cervical curvature was also reviewed in lateral radiographs. RESULTS: A total 19 patients were available to review medical records. There were 14 male and 5 female, whose mean age at the time of surgery was 61.26 years. The mean follow-up period was 68.57 months. OPLL classification scheme, continous type was in 8 patients, mixed and segmental type was 5 patients each, and others type was in one patient. The preoperative JOA score was 10.21 6 3.08, postoperative JOA score was significantly improved to 13.73 6 2.9 (p !0.001) and the recovery rate at the last follow-up was 51.95%. The preoperative global angle was -10.61 and postoperative global angle was -10.31 . The preoperative ROM was 31.0 and postoperative them was 23.4 . There was no statistical significance in change of cervical curvature and ROM. A 16 of the 19 patients were preoperatively shown lordotic cervical curvature, and 3 patients were straight. At last follow-up, 14 patients kept the lordotic curvature, 2 patients changed from lordosis to kyphosis. One patient who cervical curvature was changed from lordosis to kyphosis during follow-up period underwent cervical fusion operation after 9 years of operation. CONCLUSIONS: Through the long-term results of laminectomy in treating cervical OPLL, the postoperative kyphosis was not common in patient with OPLL. The OPLL itself may serve as supporter of spinal column. For patients with maintained cervical lordosis, cervical laminectomy can be advocated. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs. http://dx.doi.org/10.1016/j.spinee.2012.08.342
129S
P69. Does Higher Screw Density Result in Increased Curve Correction and Improved Clinical Outcomes in Adolescent Idiopathic Scoliosis (AIS) A. Noelle Larson, MD1, David W. Polly, Jr., MD2, Beverly E. Diamond, PhD3, T. Ledonio Charles Gerald, MD1, Daniel J. Sucato, MD4, Hubert Labelle, MD5, John Emans, MD6, B. Stephens Richards, MD4, Charles E. Johnston, MD4, Minimize Implants Maximize Outcomes Study Group; 1Minneapolis, MN, US; 2University of Minnesota, Minneapolis, MN, US; 3PhDx Systems Inc., Albuquerque, NM, US; 4Texas Scottish Rite Hospital for Children, Dallas, TX, US; 5Departement d’Orthopedie, Montreal, QC, Canada; 6Chest Wall and Spinal Deformity Study Group, Salt Lake City, UT, US BACKGROUND CONTEXT: There is substantial heterogeneity in anchor density (screws per level fused) in AIS surgery with little documented benefit in curve correction or patient-reported outcomes for a high density construct. PURPOSE: We sought to evaluate a large prospective database of AIS patients treated with predominantly pedicle screw contructs to determine whether anchor density was associated with curve correction and patient reported outcome scores. STUDY DESIGN/SETTING: Prospective, multicenter study. PATIENT SAMPLE: The study was comprised of 1247 patients with adolescent idiopathic scoliosis with a Lenke 1 or 2 curve type. OUTCOME MEASURES: % curve correction, SRS, and SAQ scores at 1- and 2-years. METHODS: The study was comprised of 1247 AIS patients who met inclusion criteria (Lenke 1 and 2 curves) with predominantly screw constructs (# screws/# total implants O 80%, mean 95.8% 6 5.6% screws). Mean screw density was 1.48 6 0.31. Thus, ! 1.48 screws per level fused was considered low density, and $ 1.48 was considered high density. ANCOVA analysis was undertaken to determine association of screw density with % curve correction, SRS, and SAQ scores at 1- and 2-years, controlling for flexibility, fusion length, demongraphics, and surgeon. RESULTS: High screw density compared to low density was associated with increased % curve correction in Lenke 1 curves at 1-year (69% vs. 65% correction, p50.0015), controlling for % pre-operative curve flexibility (p50.0093), length of fusion (p!0.0001), and gender (p50.078), (model, p!0.0001). For Lenke 2 curves at 1-year, high density constructs were associated with increased % major curve correction (68% vs. 63%, p50.0073), controlling for length of fusion (model, p!0.0001). Similar findings held at 2-year follow-up. Thoracic kyphosis at 2 years was negatively correlated with screw density (28 vs. 32 , p!0.0002) controlling for age and length of fusion in Lenke 1 curves (model, p!0.0001). A similar relationship was found for Lenke 2 curves (26 vs. 33 ), controlling for length of fusion and pre-op kyphosis. For Lenke 1 curves only, SRS Appearance Score at 2-years was positively associated with screw density (low: 4.15 vs. high: 4.3, p50.018). Similarly, the SAQ Appearance score similarly was improved in the high implant density group (high: 14 vs. low: 15, p50.01), with contributions from length of fusion (p50.01), and pre-operative SAQ (p!0.0001) for Lenke 1 curves. CONCLUSIONS: For Lenke 1 and 2 curve patterns, improved % correction of major coronal curve was noted at 1 year follow-up in the high screw density cohort. Although statistical significance was reached, it is unclear if screw density resulted in clinically significant differences in patient-reported outcomes. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs. http://dx.doi.org/10.1016/j.spinee.2012.08.343
P70. Minimally Invasive Posterolateral Endoscopic Treatment for Spinal Infections Ken Nagahama, MD1, Manabu Ito, MD, PhD2, Kuniyoshi Abumi, MD3; 1 Department of Orthopaedic Surgery, Hokkaido University Graduate
All referenced figures and tables will be available at the Annual Meeting and will be included with the post-meeting online content.
P68. Long-Term Follow-Up Results Following Laminectomy for Cervical Ossification of the Posterior Longitudinal Ligament Soo Eon Lee, MD1, Chun Kee Chung, MD2, Tae-Ahn Jahng, MD, PhD2; 1 Seoul, South Korea; 2Seoul National University Hospital, Seoul, South Korea BACKGROUND CONTEXT: Laminectomy is an effective surgical technique for the treatment of cervical OPLL along multilevel. However, postoperative kyphosis and probable neurological deterioration have been frequently reported after laminectomy. PURPOSE: We analyzed the changes in the cervical curvature after laminectomy and subsequent changes in neurological status in treating ossification of the posterior longitudinal ligament (OPLL) of the cervical spine. STUDY DESIGN/SETTING: Retrospective study. PATIENT SAMPLE: The authors reviewed the 38 patients who underwent cervical laminectomy between 1999 and 2003. OUTCOME MEASURES: The preoperative symptoms, Japanese Orthopedic Association (JOA) score and recovery rate was reviewed using medical records. The OPLL type was classified to continous, segmental, mixed and local type. The cervical global angle and range of motion (ROM) was measured by posterior tangent method at preoperation and the last follow-up. METHODS: According to the cervical global angle, the cervical curvature was distributed into three types; lordosis, straight, and kyphosis. The change in cervical curvature was also reviewed in lateral radiographs. RESULTS: A total 19 patients were available to review medical records. There were 14 male and 5 female, whose mean age at the time of surgery was 61.26 years. The mean follow-up period was 68.57 months. OPLL classification scheme, continous type was in 8 patients, mixed and segmental type was 5 patients each, and others type was in one patient. The preoperative JOA score was 10.21 6 3.08, postoperative JOA score was significantly improved to 13.73 6 2.9 (p !0.001) and the recovery rate at the last follow-up was 51.95%. The preoperative global angle was -10.61 and postoperative global angle was -10.31 . The preoperative ROM was 31.0 and postoperative them was 23.4 . There was no statistical significance in change of cervical curvature and ROM. A 16 of the 19 patients were preoperatively shown lordotic cervical curvature, and 3 patients were straight. At last follow-up, 14 patients kept the lordotic curvature, 2 patients changed from lordosis to kyphosis. One patient who cervical curvature was changed from lordosis to kyphosis during follow-up period underwent cervical fusion operation after 9 years of operation. CONCLUSIONS: Through the long-term results of laminectomy in treating cervical OPLL, the postoperative kyphosis was not common in patient with OPLL. The OPLL itself may serve as supporter of spinal column. For patients with maintained cervical lordosis, cervical laminectomy can be advocated. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs. http://dx.doi.org/10.1016/j.spinee.2012.08.342
129S
P69. Does Higher Screw Density Result in Increased Curve Correction and Improved Clinical Outcomes in Adolescent Idiopathic Scoliosis (AIS) A. Noelle Larson, MD1, David W. Polly, Jr., MD2, Beverly E. Diamond, PhD3, T. Ledonio Charles Gerald, MD1, Daniel J. Sucato, MD4, Hubert Labelle, MD5, John Emans, MD6, B. Stephens Richards, MD4, Charles E. Johnston, MD4, Minimize Implants Maximize Outcomes Study Group; 1Minneapolis, MN, US; 2University of Minnesota, Minneapolis, MN, US; 3PhDx Systems Inc., Albuquerque, NM, US; 4Texas Scottish Rite Hospital for Children, Dallas, TX, US; 5Departement d’Orthopedie, Montreal, QC, Canada; 6Chest Wall and Spinal Deformity Study Group, Salt Lake City, UT, US BACKGROUND CONTEXT: There is substantial heterogeneity in anchor density (screws per level fused) in AIS surgery with little documented benefit in curve correction or patient-reported outcomes for a high density construct. PURPOSE: We sought to evaluate a large prospective database of AIS patients treated with predominantly pedicle screw contructs to determine whether anchor density was associated with curve correction and patient reported outcome scores. STUDY DESIGN/SETTING: Prospective, multicenter study. PATIENT SAMPLE: The study was comprised of 1247 patients with adolescent idiopathic scoliosis with a Lenke 1 or 2 curve type. OUTCOME MEASURES: % curve correction, SRS, and SAQ scores at 1- and 2-years. METHODS: The study was comprised of 1247 AIS patients who met inclusion criteria (Lenke 1 and 2 curves) with predominantly screw constructs (# screws/# total implants O 80%, mean 95.8% 6 5.6% screws). Mean screw density was 1.48 6 0.31. Thus, ! 1.48 screws per level fused was considered low density, and $ 1.48 was considered high density. ANCOVA analysis was undertaken to determine association of screw density with % curve correction, SRS, and SAQ scores at 1- and 2-years, controlling for flexibility, fusion length, demongraphics, and surgeon. RESULTS: High screw density compared to low density was associated with increased % curve correction in Lenke 1 curves at 1-year (69% vs. 65% correction, p50.0015), controlling for % pre-operative curve flexibility (p50.0093), length of fusion (p!0.0001), and gender (p50.078), (model, p!0.0001). For Lenke 2 curves at 1-year, high density constructs were associated with increased % major curve correction (68% vs. 63%, p50.0073), controlling for length of fusion (model, p!0.0001). Similar findings held at 2-year follow-up. Thoracic kyphosis at 2 years was negatively correlated with screw density (28 vs. 32 , p!0.0002) controlling for age and length of fusion in Lenke 1 curves (model, p!0.0001). A similar relationship was found for Lenke 2 curves (26 vs. 33 ), controlling for length of fusion and pre-op kyphosis. For Lenke 1 curves only, SRS Appearance Score at 2-years was positively associated with screw density (low: 4.15 vs. high: 4.3, p50.018). Similarly, the SAQ Appearance score similarly was improved in the high implant density group (high: 14 vs. low: 15, p50.01), with contributions from length of fusion (p50.01), and pre-operative SAQ (p!0.0001) for Lenke 1 curves. CONCLUSIONS: For Lenke 1 and 2 curve patterns, improved % correction of major coronal curve was noted at 1 year follow-up in the high screw density cohort. Although statistical significance was reached, it is unclear if screw density resulted in clinically significant differences in patient-reported outcomes. FDA DEVICE/DRUG STATUS: This abstract does not discuss or include any applicable devices or drugs. http://dx.doi.org/10.1016/j.spinee.2012.08.343
P70. Minimally Invasive Posterolateral Endoscopic Treatment for Spinal Infections Ken Nagahama, MD1, Manabu Ito, MD, PhD2, Kuniyoshi Abumi, MD3; 1 Department of Orthopaedic Surgery, Hokkaido University Graduate
All referenced figures and tables will be available at the Annual Meeting and will be included with the post-meeting online content.