• 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.

• Journal of the Korean Orthopaedic Association
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• v.54 no.2
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• pp.141-149
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• 2019

Purpose: To compare the results of two different instruments made of stainless steel and titanium alloy for correction of single thoracic adolescent idiopathic scoliosis (AIS) using pedicle screw instrumentation. Materials and Methods: A total of 141 patients with single thoracic AIS treated with pedicle screw instrumentation and selective thoracic fusion were retrospectively reviewed after a follow-up of 2 years. The patients had a main thoracic curve of 40° to 75° and were divided into two groups based on instrument materials; S group (stainless steel, n=90) and T group (titanium alloy, n=51). The diameter of the stainless steel rod used was 7.0 mm while that of the titanium alloy rod was 6.35 mm or 6.0 mm. Standing long-cassette radiographic measurements including various coronal and sagittal parameters for the preoperative, early postoperative and 2-year postoperative followup were analyzed. There were no significant differences in the preoperative curve characteristics between the two groups. Results: In the S group, the preoperative main thoracic curve of 51.3°±8.4° was improved to 19.0°±7.6° (63.1% correction) and the lumbar curve of 32.3°±8.4° spontaneously decreased to 12.7°±8.2° (62.9% correction) at 2 years postoperatively. In the T group, the preoperative main thoracic curve of 49.5°±8.4° and the lumbar curve of 30.3°±8.9° was improved to 18.8°±7.4° (62.2% correction) and 11.3°±5.4° (63.3% correction), respectively. The corrections of coronal curves were not statistically different between the two groups (p>0.05). The thoracic kyphosis was changed from 16.8°±8.5° to 24.3°±6.1° in the S group and from 19.6°±11.2° to 26.6°±8.5° in the T group. There were no significant differences in the changes of sagittal curves, coronal and sagittal balances at the 2-year follow-up and the number of fused segments and used screws between the two groups (p>0.05). Conclusion: When conducting surgery for single thoracic AIS using pedicles screw instrumentation, two different instruments made of stainless steel and titanium alloy showed similar corrections for coronal and sagittal curves.

• Journal of Korean Neurosurgical Society
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• v.48 no.2
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• pp.129-133
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• 2010

Objective : The use of segmental instrumentation technique using pedicle screw has been increasingly popular in recent years owing to its biomechanical stability. Recently, intralaminar screws have been used as a potentially safer alternative to traditional fusion constructs involving fixation of C2 and the cervicothoracic junction including C7. However, to date, there have been few clinical series of C7 laminar screw fixation in the literature. Thus, the purpose of this study is to report our clinical experiences using C7 laminar screw and the early clinical outcome of this rather new fixation technique. Methods : Thirteen patients underwent C7 intralaminar fixation to treat lesions from trauma or degenerative disease. Seventeen intralaminar screws were placed at C7. The patients were assessed both clinically and radiographically with postoperative computed tomographic scans. Results : There was no violation of the screw into the spinal canal during the procedure and no neurological worsening or vascular injury from screw placement. The mean clinical and radiographic follow up was about 19 months, at which time there were no cases of screw pull-out, screw fracture or non-union. Complications included two cases of dorsal breech of intralaminar screw and one case of postoperative infection. Conclusion : Intralaminar screws can be potentially safe alternative technique for C7 fixation. Even though this technique cannot be used in the cases of C7 laminar fracture, large margin of safety and the ease of screw placement create a niche for this technique in the armamentarium of spine surgeons.

• Journal of Korean Neurosurgical Society
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• v.55 no.5
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• pp.289-292
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• 2014

A case of total spondyloptosis of the cervical spine at C6-7 level with cord compression is described in a 51-year-old male. Because the bodies of C6 and 7 were tightly locked together, cervical traction failed. Then the patient was operated on by a posterior approach. Posterior stabilization and fusion were performed by C4-5 lateral mass and C7-T1 pedicle screw fixation and rod instrumentation with bridging both C4-5's rods to the C7-T1's extended ones. After C6 total laminectomy and foraminotomy, the C6 body was returned to its proper position. Secondly, anterior stabilization and fusion were performed by C6-7 discectomy with a screw-plate system. A postoperative lateral plain radiograph showed good realignment. In this case, we report the clinical presentation and discuss the surgical modalities of C6-7 total spondyloptosis and the failed close reduction.

• Journal of Korean Neurosurgical Society
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• v.51 no.6
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• pp.343-349
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• 2012

Objective : Pedicle-based dynamic stabilization systems, in which semi-rigid rods or cords are used to restrict or control spinal segmental motion, aim to reduce or eliminate the drawbacks associated with rigid fusion. In this study, we analyzed the two-year clinical outcomes of patients treated with the NFlex (Synthes Spine, Inc.), a pedicle-based dynamic stabilization system. Methods : Five sites participated in a retrospective study of 72 consecutive patients who underwent NFlex stabilization. Of these 72 patients, 65 were available for 2-year follow-up. Patients were included based on the presence of degenerative disc disease (29 patients), degenerative spondylolisthesis (16 patients), lumbar stenosis (9 patients), adjacent segment degeneration (6 patients), and degenerative lumbar scoliosis (5 patients). The clinical outcome measures at each assessment were Visual Analogue Scale (VAS) to measure back pain, and Oswestry Disability Index (ODI) to measure functional status. Radiographic assessments included evidence of instrumentation failure or screw loosening. Results : Sixty-five patients (26 men and 39 women) with a mean age of 54.5 years were included. Mean follow-up was 25.6 months. The mean VAS score improved from 8.1 preoperatively to 3.8 postoperatively, representing a 53% improvement, and the ODI score from 44.5 to 21.8, representing a 51% improvement. Improvements in pain and disability scores were statistically significant. Three implant-related complications were observed. Conclusion : Posterior pedicle-based dynamic stabilization using the NFlex system seems effective in improving pain and functional scores, with sustained clinical improvement after two years. With appropriate patient selection, it may be considered an effective alternative to rigid fusion.

• Journal of Korean Neurosurgical Society
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• v.58 no.6
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• pp.534-538
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• 2015

Objective : To correct apical vertebral rotation for adolescent idiopathic scoliosis (AIS), direct vertebral derotation (DVD) or simple rod rotation (SRR) might be considered. The aim of the present study is to introduce the surgical experiences of AIS by a Korean neurosurgeon and to evaluate the effectiveness of SRR for apical vertebral rotation. Methods : A total of 9 patients (1 male and 8 females) underwent scoliosis surgery by a neurosurgeon of our hospital. The Lenke classifications of the patients were 1 of 1B, 2 of 1C, 1 of 2A, 1 of 2C, 3 of 5C and 1 of 6C. Surgery was done by manner of simple rod rotation on the concave side and in situ coronal bending. Coronal Cobb's angles, vertebral rotation angles and SRS-22 were measured on a plain standing X-ray and CT before and after surgery. Results : The mean follow up period was 25.7 months (range : 5-52). The mean number of screw positioning level was nine (6-12). The mean age was 16.4 years (range : 13-25) at surgery. The mean Risser grade was $3.7{\pm}0.9$. The apical vertebral rotation measured from the CT scans was $25.8{\pm}8.5^{\circ}$ vs. $9.3{\pm}6.7^{\circ}$ (p<0.001) and the Coronal Cobb's angle was $53.7{\pm}10.4^{\circ}$ vs. $15.4{\pm}6.5^{\circ}$ (p<0.001) preoperatively and postoperative, respectively. The SRS-22 improved from 71.9 preoperatively to 90.3 postoperatively. There were no complications related with the operations. Conclusion : SRR with pedicle screw instrumentation could be corrected successfully by axial rotation without complications. SRR might serve as a good option to correct AIS deformed curves of AIS.

• Journal of Yeungnam Medical Science
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• v.20 no.2
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• pp.160-168
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• 2003

Background: Confirm the stability of intervertebral disc sustaining each fused lumbar spine cases, comparing vertical compression, A-P shear force and rotational moment on intervertebral disc of instrumented lumbar spine with simple vertical compression load and follower load using finite element analysis. Materials and Methods: We analyze the stability of intervertebral disc L4-5 supporting fused lumbar spine segments. After performing finite element modelling about L1-L5 lumbar vertebral column and L1-L4 each fusion level pedicle screw system for fused lumbar spine fine element model. Intervertebral discs with complex structure and mechanical properties was modeled using spring element that compensate stiffness and tube-to-tube contact element was employed to give follower load. Performing geometrical non-linear analysis. Results: The differences of intervertebral disc L4-5 behavior under the follower compression load in comparision with vertical compression load are as follows. Conclusion: As a result of finite element interpretation of instrumented lumbar spine, the stability of L4-5 sustaining fused lumbar segment, the long level fused lumbar spine observed hing stability under follower load. This research method can be the basis tool of effects prediction for instrumentation, a invention of a more precious finite element interpretation model which consider the role of muscle around the spine is loaded.

• International Journal of Control, Automation, and Systems
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• v.4 no.1
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• pp.30-41
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• 2006

The goal of this work is to develop and test a robot-assisted surgery system for spinal fusion. The system is composed of a robot, a surgical planning system, and a navigation system. It plays the role of assisting surgeons for inserting a pedicle screw in the spinal fusion procedure. Compared to conventional methods for spinal fusion, the proposed surgical procedure ensures minimum invasion and better accuracy by using robot and image information. The robot plays the role of positioning and guiding needles, drills, and other surgical instruments or conducts automatic boring and screwing. Pre-operative CT images intra-operative fluoroscopic images are integrated to provide the surgeon with information for surgical planning. Some experiments employing the developed robotic surgery system are conducted. The experimental results confirm that the system is not only able to guide the surgical tools by accurately pointing and orienting the specified location, but also successfully compensate the movement of the patient due to respiration.

• 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.58 no.1
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• pp.50-53
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• 2015

Objective : The purpose of this study was to evaluate radiographic/clinical outcomes of adolescent idiopathic scoliosis (AIS) patients treated by a Korean neurosurgeon. Methods : Ten AIS patients were treated by a single neurosurgeon between January 2011 and September 2013 utilizing segmental instrumentation with pedicle screws. Basic demographic information, curve pattern by Lenke classification, number of levels treated, amount of correction achieved, radiographic/clinical outcomes [by Scolisis Resarch Society (SRS-22r) questionnaire] and complications were evaluated to determine the surgical results. Pulmonary function test was utilized to assess forced vital capacity (FVC) and forced expiratory volume in one second (FEV1) before and after surgery. Results : The average percentage of correction of the major structural curve was 73.6% (ranged from 64% to 81.5%). Preoperative and final postoperative absolute FVC averaged 3.03 L and 3.76 L (0.73 L increase, p=0.046), and absolute FEV1 averaged 2.63 L and 3.49 L (0.86 L increase, p=0.021). Preoperative and final postoperative average self-image and function scores of SRS-22r were, $2.6{\pm}0.5$, $3.3{\pm}0.1$, $4.0{\pm}0.5$, and $4.6{\pm}0.0$, respectively. There was a significant improvement of the self-image and function scores of SRS-22r questionnaires before and after surgery (p<0.05). There was no case of neurological deficit, infection and revision for screw malposition. One patient underwent a fusion extension surgery for shoulder asymmetry. Conclusion : Radiographic/clinical outcomes of AIS patients treated by a Korean neurosurgeon were acceptable. Fundamental understanding of pediatric spinal deformity is essential for the practice of AIS surgery.