• Journal of the Korean Society for Precision Engineering
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• v.27 no.2
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• pp.130-136
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• 2010

For stability analysis of the lumbar spine, the hypothesis presented is that the disc has stress sensors driving feedback mechanism, which could react to the imposed loads by adjusting the contraction of the muscles. Fusion in the motion segment of the lumbar spinal column is believed to alter the stability of the spinal column. To identify this effect finite element (FE) models combined with optimization technique was applied and quantify the role of each muscle and reaction forces in the spinal column with respect to the fusion level. The musculoskeletal FE model was consisted with detailed whole lumbar spine, pelvis, sacrum, coccyx and simplified trunk model. Vertebral body and pelvis were modeled as a rigid body and the rib cage was constructed with rigid truss element for the computational efficiency. Spinal fusion model was applied to L3-L4, L4-L5, L5-S1 (single level) and L3-L5 (two levels) segments. Muscle architecture with 46 local muscles was used as acting directions. Minimization of the nucleus pressure deviation and annulus fiber average axial stress deviation was selected for cost function. As a result, spinal fusion produced reaction changes at each motion segment as well as contribution of each muscle. Longissimus thoracis and psoas major muscle showed dramatic changes for the cases of L5-S1 and L3-L5 level fusion. Muscle force change at each muscle also generated relatively high nucleus pressure not only at the adjacent level but at another level, which can explain disc degeneration pattern observed in clinical study.

• Journal of Korean Neurosurgical Society
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• v.64 no.4
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• pp.486-494
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• 2021

The growth of pulsed electromagnetic field (PEMF) therapy and its progress over the years for use in post-operative bone growth has been revolutionary in its effect on bone tissue proliferation and vascular flow. However, further progress in PEMF therapy has been difficult due to lack of more evidence-based understanding of its mechanism of action. Our objective was to review the current understanding of bone growth physiology, the mechanism of PEMF therapy action along with its application in spinal surgery and associated outcomes. The authors of this review examined multiple controlled, comparative, and cohort studies to compare fusion rates of patients undergoing PEMF stimulation. Examining spinal fusion rates, a rounded comparison of post-fusion outcomes with and without bone stimulator was performed. Results showed that postoperative spinal surgery PEMF stimulation had higher rates of fusion than control groups. Though PEMF therapy was proven more effective, multiple factors contributed to difficulty in patient compliance for use. Extended timeframe of treatment and cost of treatment were the main obstacles to full compliance. This review showed that PEMF therapy presented an increased rate of recovery in patients, supporting the use of these devices as an effective post-surgical aid. Given the recent advances in the development of PEMF devices, affordability and access will be much easier suited to the patient population, allowing for more readily available treatment options.

• Journal of Korean Neurosurgical Society
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• v.60 no.3
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• pp.348-354
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• 2017

Objective : To identify and investigate differences in spinal fusion between the normal and osteopenic spine in a rat model. Methods : Female Sprague Dawley rats underwent either an ovariectomy (OVX) or sham operation and were randomized into two groups: non-OVX group and OVX group. Eight weeks after OVX, unilateral lumbar spinal fusion was performed using autologous iliac bone. Bone density (BD) was measured 2 days and 8 weeks after fusion surgery. Microcomputed tomography was used to evaluate the process of bone fusion every two weeks for 8 weeks after fusion surgery. The fusion rate, fusion process, and bone volume parameters of fusion bed were compared between the two groups. Results : BD was significantly higher in the non-OVX group than in the OVX group 2 days and 8 weeks after fusion surgery. The fusion rate in the non-OVX group was higher than that in the OVX group 8 weeks after surgery (p=0.044). The bony connection of bone fragments with transverse processes and bone formation between transverse processes in non-OVX group were significantly superior to those of OVX group from 6 weeks after fusion surgery. The compactness and bone maturation of fusion bed in non-OVX were prominent compared with the non-OVX group. Conclusion : The fusion rate in OVX group was inferior to non-OVX group at late stage after fusion surgery. Bone maturation of fusion bed in the OVX group was inferior compared with the non-OVX group. Fusion enhancement strategies at early stage may be needed to patients with osteoporosis who need spine fusion surgery.

• Journal of Korean Neurosurgical Society
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• v.56 no.4
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• pp.310-314
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• 2014

Objective : To analyze the clinical courses and outcomes after anterior lumbar interbody fusion (ALIF) for the treatment of postoperative spondylodiscitis. Methods : A total of 13 consecutive patients with postoperative spondylodiscitis treated with ALIF at our institute from January, 1994 to August, 2013 were included (92.3% male, mean age 54.5 years old). The outcome data including inflammatory markers (leukocyte count, C-reactive protein, erythrocyte sedimentation rate), the Oswestry Disability Index (ODI), the modified Visual Analogue Scale (VAS), and bony fusion rate using spine X-ray were obtained before and 6 months after ALIF. Results : All of the cases were effectively treated with combination of systemic antibiotics and ALIF with normalization of the inflammatory markers. The mean VAS for back and leg pain before ALIF was $6.8{\pm}1.1$, which improved to $3.2{\pm}2.2$ at 6 months after ALIF. The mean ODI score before ALIF was $70.0{\pm}14.8$, which improved to $34.2{\pm}27.0$ at 6 months after ALIF. Successful bony fusion rate was 84.6% (11/13) and the remaining two patients were also asymptomatic. Conclusion : Our results suggest that ALIF is an effective treatment option for postoperative spondylodiscitis.

• 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.

• Journal of Chest Surgery
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• v.48 no.6
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• pp.443-446
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• 2015

A 36-year-old man, who had undergone thoracoscopic anterior spinal fusion using the plate system and posterior screw fusion three months previously, presented to our hospital with left flank pain and fever. Computed tomography indicated the presence of a psoas muscle abscess. However, after two days of percutaneous catheter drainage, a mycotic abdominal aortic pseudoaneurysm was detected via computed tomography. We performed in situ revascularization using a prosthetic graft with omental wrapping. Methicillin-resistant Staphylococcus aureus was identified on blood and pus culture, and systemic vancomycin was administered for one month. Although the abscess recurred, it was successfully treated with percutaneous catheter drainage and systemic vancomycin administration for three months, without the need for instrumentation removal. The patient remained asymptomatic throughout two years of follow-up.

• Journal of Korean Neurosurgical Society
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• v.58 no.1
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• pp.65-71
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• 2015

Objective : Lumbar spinal stenosis is conventionally treated with surgical decompression. However, bilateral decompression and laminectomy is more invasive and may not be necessary for lumbar stenosis patients with unilateral radiculopathy. We aimed to report the outcomes of unilateral laminectomy and bilateral pedicle screw fixation with fusion for patients with lumbar spinal stenosis and unilateral radiculopathy. Methods : Patients with lumbar spinal stenosis with unilateral lower extremity radiculopathy who received limited unilateral decompression and bilateral pedicle screw fixation were included and evaluated using visual analog scale (VAS) pain and the Oswestry Disability Index (ODI) scores preoperatively and at follow-up visits. Ligamentum flavum thickness of the involved segments was measured on axial magnetic resonance images. Results : Twenty-five patients were included. The mean preoperative VAS score was $6.6{\pm}1.6$ and $4.6{\pm}3.1$ for leg and back pain, respectively. Ligamentum flavum thickness was comparable between the symptomatic and asymptomatic side (p=0.554). The mean follow-up duration was 29.2 months. The pain in the symptomatic side lower extremity (VAS score, $1.32{\pm}1.2$) and the back (VAS score, $1.75{\pm}1.73$) significantly improved (p=0.000 vs. baseline for both). The ODI improved significantly postoperatively ($6.60{\pm}6.5$; p=0.000 vs. baseline). Significant improvement in VAS pain and ODI scores were observed in patients receiving single or multi-segment decompression fusion with fixation (p<0.01). Conclusion : Limited laminectomy and unilateral spinal decompression followed by bilateral pedicle screw fixation with fusion achieves satisfactory outcomes in patients with spinal stenosis and unilateral radiculopathy. This procedure is less damaging to structures that are important for maintaining posterior stability of the spine.

• Asian Spine Journal
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• v.12 no.6
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• pp.1060-1068
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• 2018

Study Design: Retrospective study. Purpose: Lumbar intervertebral disc degeneration is an important cause of low back pain. Overview of Literature: Spinal fusion is often reported to have a good course for adolescent idiopathic scoliosis (AIS). However, many studies have reported that adjacent segment degeneration is accelerated after lumbar spinal fusion. Radiography is a simple method used to evaluate the orientation of the vertebral column. magnetic resonance imaging (MRI) is the method most often used to specifically evaluate intervertebral disc degeneration. The Pfirrmann classification is a well-known method used to evaluate degenerative lumbar disease. After spinal fusion, an increase in stress, excess mobility, increased intra-disc pressure, and posterior displacement of the axis of motion have been observed in the adjacent segments. Methods: we retrospectively secured and analyzed the data of 15 patients (four boys and 11 girls) with AIS who underwent a spinal fusion surgery. We studied the full-length view of the spine (anterior-posterior and lateral) from the X-ray and MRI obtained from all patients before surgery. Postoperatively, another full-length spine X-ray and lumbosacral MRI were obtained from all participants. Then, pelvic tilt, sacral slope, curve correction, and fused and free segments before and after surgery were calculated based on X-ray studies. MRI images were used to estimate the degree to which intervertebral discs were degenerated using Pfirrmann grading system. Pfirrmann grade before and after surgery were compared with Wilcoxon signed rank test. While analyzing the contribution of potential risk factors for the post-spinal fusion Pfirrmann grade of disc degeneration, we used generalized linear models with robust standard error estimates to account for intraclass correlation that may have been present between discs of the same patient. Results: The mean age of the participant was 14 years, and the mean curvature before and after surgery were 67.8 and 23.8, respectively (p<0.05). During the median follow-up of 5 years, the mean degree of the disc degeneration significantly increased in all patients after surgery (p<0.05) with a Pfirrmann grade of 1 and 2.8 in the L2-L3 before and after surgery, respectively. The corresponding figures at L3-L4, L4-L5, and L5-S1 levels were 1.28 and 2.43, 1.07 and 2.35, and 1 and 2.33, respectively. The lower was the number of free discs below the fusion level, the higher was the Pfirrmann grade of degeneration (p<0.001). Conversely, the higher was the number of the discs fused together, the higher was the Pfirrmann grade. Conclusions: we observed that the disc degeneration aggravated after spinal fusion for scoliosis. While the degree of degeneration as measured by Pfirrmann grade was directly correlated by the number of fused segments, it was negatively correlated with the number of discs that remained free below the lowermost level of the fusion.

• Journal of Biomedical Engineering Research
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• v.26 no.5
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• pp.265-270
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• 2005

A new Computer Integrated Surgical Robot system is composed of a surgical robot, a surgical planning system, and an optical tracking system. The system plays roles of an assisting surgeon and taking the place of surgeons for inserting a pedicle screw in spinal fusion. Compared to pure surgical navigation systems as well as conventional methods for spinal fusion, it is able to achieve better accuracy through compensating for the portending movement of the surgical target area. Furthermore, the robot can position and guide needles, drills, and other surgical instruments or conducts drilling/screwing directly. Preoperatively, the desired entry point, orientation, and depth of surgical tools for pedicle screw insertion are determined by the surgical planning system based on CT/MR images. Intra-operatively, position information on surgical instruments and targeted surgical areas is obtained from the navigation system. Two exemplary experiments employing the developed image-guided surgical robot system are conducted.

• The Journal of Churna Manual Medicine for Spine and Nerves
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• v.6 no.2
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• pp.133-143
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• 2011

Objectives : The present study introduces the clinical application of Hamstring Chuna Manual Therapy to a patient who underwent the pain after spinal fusion. Methods : A patient who had the pain after spinal fusion was hospitalized at Bucheon Jaseng hospital of Oriental Medicine for 35 days. During the hospital treatment, the pain was relieved by Hamstring Chuna Manual Therapy. The improvement of the patient was measured by VAS(Visual Analogue Scale) score, SLR(Straight-Leg Raising) test, and walking distance. Results : The values of the patient's VAS score, SLR test, and walking distance measured before and after Hamstring Chuna Manual Therapy presented that the pain was relieved after Hamstring Chuna Manual Therapy. Conclusions : Therefore, this case demonstrates that Hamstring Chuna Manual Therapy is effective treatment method for relieving pain in the spine.