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http://dx.doi.org/10.3340/jkns.2014.55.5.248
Print ISSN 2005-3711 On-line ISSN 1598-7876
Copyright © 2014 The Korean Neurosurgical Society
J Korean Neurosurg Soc 55 (5) : 248-254, 2014
Clinical Article
Direct Lateral Lumbar Interbody Fusion : Clinical and Radiological Outcomes Young Seok Lee, M.D., Seung Won Park, M.D., Ph.D., Young Baeg Kim, M.D., Ph.D. Department of Neurosurgery, Chung-Ang University Hospital, Seoul, Korea Objective : According to the recent development of minimally invasive spinal surgery, direct lumbar interbody fusion (DLIF) was introduced as an effective option to treat lumbar degenerative diseases. However, comprehensive results of DLIF have not been reported in Korea yet. The object of this study is to summarize radiological and clinical outcomes of our DLIF experience. Methods : We performed DLIF for 130 patients from May 2011 to June 2013. Among them, 90 patients, who could be followed up for more than 6 months, were analyzed retrospectively. Clinical outcomes were compared using visual analog scale (VAS) score and Oswestry Disability Index (ODI). Bilateral foramen areas, disc height, segmental coronal and sagittal angle, and regional sagittal angle were measured. Additionally, fusion rate was assessed. Results : A total of 90 patients, 116 levels, were underwent DLIF. The VAS and ODI improved statistically significant after surgery. All the approaches for DLIF were done on the left side. The left and right side foramen area changed from 99.5 mm² and 102.9 mm² to 159.2 mm² and 151.2 mm² postoperatively (p60%, respectively20). We analyzed the postoperative changes in the segmental sagittal angles depending on the cage position. The fusion was evaluated based on the Bridwell fusion grading system4). According to the Bridwell fusion grading system, the fusion is evaluated as grade 1; completely remodeled with trabeculae across disc space, grade 2; graft intact with no lucent lines seen between graft and adjacent endplates, grade 3; graft intact, but a radiolucent line is seen between the graft and an adjacent endplate, grade 4; lucency along an entire border of the graft, or lucency around a pedicle screw or subsidence of the graft. Based on this classification system, grade 1--2 was determined to be successful fusion. We analyzed the fusion rate at six months postoperatively (n=69) and one year (n=41). If there was a graft migration to the adjacent endplate at a distance of >2 mm at a 6-month follow-up radiography, the corresponding cases were considered to have a subsidence.
Statistical analysis We compared the radiological and clinical outcomes between preoperatively and postoperatively using a paired t-test and Wilcoxon signed-rank test. In addition, we also compared the VAS and ODI on the symptom side using Kruskall-Wallis test. Fur-
249
J Korean Neurosurg Soc 55 | May 2014
thermore, we compared the subsidence using the chi-square test. A p-value of
http://dx.doi.org/10.3340/jkns.2014.55.5.248
Print ISSN 2005-3711 On-line ISSN 1598-7876
Copyright © 2014 The Korean Neurosurgical Society
J Korean Neurosurg Soc 55 (5) : 248-254, 2014
Clinical Article
Direct Lateral Lumbar Interbody Fusion : Clinical and Radiological Outcomes Young Seok Lee, M.D., Seung Won Park, M.D., Ph.D., Young Baeg Kim, M.D., Ph.D. Department of Neurosurgery, Chung-Ang University Hospital, Seoul, Korea Objective : According to the recent development of minimally invasive spinal surgery, direct lumbar interbody fusion (DLIF) was introduced as an effective option to treat lumbar degenerative diseases. However, comprehensive results of DLIF have not been reported in Korea yet. The object of this study is to summarize radiological and clinical outcomes of our DLIF experience. Methods : We performed DLIF for 130 patients from May 2011 to June 2013. Among them, 90 patients, who could be followed up for more than 6 months, were analyzed retrospectively. Clinical outcomes were compared using visual analog scale (VAS) score and Oswestry Disability Index (ODI). Bilateral foramen areas, disc height, segmental coronal and sagittal angle, and regional sagittal angle were measured. Additionally, fusion rate was assessed. Results : A total of 90 patients, 116 levels, were underwent DLIF. The VAS and ODI improved statistically significant after surgery. All the approaches for DLIF were done on the left side. The left and right side foramen area changed from 99.5 mm² and 102.9 mm² to 159.2 mm² and 151.2 mm² postoperatively (p60%, respectively20). We analyzed the postoperative changes in the segmental sagittal angles depending on the cage position. The fusion was evaluated based on the Bridwell fusion grading system4). According to the Bridwell fusion grading system, the fusion is evaluated as grade 1; completely remodeled with trabeculae across disc space, grade 2; graft intact with no lucent lines seen between graft and adjacent endplates, grade 3; graft intact, but a radiolucent line is seen between the graft and an adjacent endplate, grade 4; lucency along an entire border of the graft, or lucency around a pedicle screw or subsidence of the graft. Based on this classification system, grade 1--2 was determined to be successful fusion. We analyzed the fusion rate at six months postoperatively (n=69) and one year (n=41). If there was a graft migration to the adjacent endplate at a distance of >2 mm at a 6-month follow-up radiography, the corresponding cases were considered to have a subsidence.
Statistical analysis We compared the radiological and clinical outcomes between preoperatively and postoperatively using a paired t-test and Wilcoxon signed-rank test. In addition, we also compared the VAS and ODI on the symptom side using Kruskall-Wallis test. Fur-
249
J Korean Neurosurg Soc 55 | May 2014
thermore, we compared the subsidence using the chi-square test. A p-value of
