• Journal of Biomedical Engineering Research
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• v.25 no.1
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• pp.71-76
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• 2004

In order to investigate the Post-operative changes in scoliotic spine according to selection of fusion level a mathematical finite element model of King-Moe type II scoliotics spine system was developed. By utilizing this finite element scoliosis model surgical correction simulation procedures of pedicle fixation and derotation were simulated. In consequence of the calculation by changing the fusion Levels, postoperative changes like Cobb angle, apical vertebrae axial rotation (AVAR), thoracic kyphosis, and rib hump were Qualitatively analyzed. In the analysis of operative kinematics, the decrease or Cobb angle was most prominent in distraction than in deroation. Applying the rod derotation only was not effective in decrease of Cobb angle but just caused increase of At AR and rib hump. From the operative simulation, co-action or distraction and translation during rod insertion has major impact on Cobb angle decrease and maintenance of kyphosis. With rod rotation, Cobb angle decrease was obtained, but combined increase of AVAR and rib hump was simulation observed as well. The case of most extended instrumentation range with 60o rod rotation produced double decrease of Cobb angle, but the increase of rib hump and AYAR occurred corresponding1y. The optimum selection of fusion level was proved as one level less than inflection position of the thoracic spine curvature.

• Journal of Korean Neurosurgical Society
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• v.60 no.2
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• pp.225-231
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• 2017

Objective : Solid bone fusion is an essential process in spinal stabilization surgery. Recently, as several minimally invasive spinal surgeries have developed, a need of artificial bone substitutes such as demineralized bone matrix (DBM), has arisen. We investigated the in vivo bone growth rate of DBM as a bone void filler compared to a local autologous bone grafts. Methods : From April 2014 to August 2015, 20 patients with a one or two-level spinal stenosis were included. A posterior lumbar interbody fusion using two cages and pedicle screw fixation was performed for every patient, and each cage was packed with autologous local bone and DBM. Clinical outcomes were assessed using the Numeric Rating Scale (NRS) of leg pain and back pain and the Korean Oswestry Disability Index (K-ODI). Clinical outcome parameters and range of motion (ROM) of the operated level were collected preoperatively and at 3 months, 6 months, and 1 year postoperatively. Computed tomography was performed 1 year after fusion surgery and bone growth of the autologous bone grafts and DBM were analyzed by ImageJ software. Results : Eighteen patients completed 1 year of follow-up, including 10 men and 8 women, and the mean age was 56.4 (32-71). The operated level ranged from L3/4 to L5/S1. Eleven patients had single level and 7 patients had two-level repairs. The mean back pain NRS improved from 4.61 to 2.78 (p=0.003) and the leg pain NRS improved from 6.89 to 2.39 (p<0.001). The mean K-ODI score also improved from 27.33 to 13.83 (p<0.001). The ROM decreased below 2.0 degrees at the 3-month assessment, and remained less than 2 degrees through the 1 year postoperative assessment. Every local autologous bone graft and DBM packed cage showed bone bridge formation. On the quantitative analysis of bone growth, the autologous bone grafts showed significantly higher bone growth compared to DBM on both coronal and sagittal images (p<0.001 and p=0.028, respectively). Osteoporotic patients showed less bone growth on sagittal images. Conclusion : Though DBM alone can induce favorable bone bridging in lumbar interbody fusion, it is still inferior to autologous bone grafts. Therefore, DBM is recommended as a bone graft extender rather than bone void filler, particularly in patients with osteoporosis.

• Journal of Korean Neurosurgical Society
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• v.46 no.4
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• pp.322-327
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• 2009

Objective : Posterior lumbar interbody fusion (PLIF) is considered to have the best theoretical potential in promoting bony fusion of unstable vertebral segments by way of a load sharing effect of the anterior column. This study was undertaken to investigate the efficacy of PLIF with cages in chronic degenerative disc disease with Modic degeneration (changes of vertebral end plate). Methods : A total of 597 patients underwent a PLIF with threaded fusion cages (TFC) from 1993 to 2000. Three-hundred-fifty-one patients, who could be followed for more than 3 years, were enrolled in this study. Patients were grouped into 4 categories according to Modic classification (no degeneration : 259, type 1 : 26, type 2 : 55, type 3 : 11). Clinical and radiographic data were evaluated retrospectively. Results : The clinical success rate according to the Prolo's functional and economic outcome scale was 86% in patients without degeneration and 83% in patients with Modic degeneration. The clinical outcomes in each group were 88% in type 1, 84% in type 2, and 73% in type 3. The bony fusion rate was 97% in patients without degeneration and 83% in patients with Modic degeneration. The bony fusion rate in each group was 81% in type 1, 84% in type 2, and 55% in type 3. The clinical success and fusion rates were significantly lower in patients with type 3 degeneration. Conclusion : The PLIF with TFC has been found to be an effective procedure for lumbar spine fusion. But, the clinical outcome and bony fusion rates were significantly low in the patients with Modic type 3. The authors suggest that PLIF combined with pedicle screw fixation would be the better for them.