• 한국컴퓨터정보학회:학술대회논문집
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• 한국컴퓨터정보학회 2017년도 제56차 하계학술대회논문집 25권2호
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• pp.99-100
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• 2017

많은 연구에서 측면 나사 고정(laminar screw fixation)보다 척추경 나사 고정(pedicle screw fixation)의 생체 역학 강도가 더 나은 것으로 알려져 있다. 그러나 비교적 작은 크기의 척추경(pedicle)과 척수(spinal code), 신경 뿌리 및 척추 동맥에 대한 상해의 위험으로 일반적으로 이 방법은 사용에 제한이 있었다. 최근 3차원 모델링 및 3D 프린팅 기술의 진보는 해부학적인 연구, 특히 척추를 포함한 뼈와 관련된 연구를 용이하게 하고 있으며, 로봇 수술을 위한 다양한 아이디어를 제공하고 있다. 본 연구는 로봇 암(robotic arm)으로 경추 척추경에 나사를 삽입할 때 사용될 수 있는 척추경 나사 삽입을 위한 이상적인 궤적을 계산하는 방법을 제시하였다.

• Journal of Korean Neurosurgical Society
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• 제46권1호
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• pp.5-10
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• 2009

Objective: The purpose of this study is to evaluate the effectiveness of unilateral decompression and pedicle screw fixation for the unilateral symptomatic foraminal stenosis. Methods: The study group comprises consecutive 16 patients who underwent unilateral decompression and bone cement augmented pedicle screw fixation from May 2003 to January 2006. The patients were evaluated by visual analog scale (VAS) for pain and the scoring system of the Japanese Orthopedic Association (JOA) for low back pain. The result of surgery was also evaluated with McNab's classification. Excellent or good outcome was considered as successful. The patients were followed at postoperative 1 month, 3 month, 6 month, and 1 year with standing AP and lateral films. Results: The average VAS and JOA score of the 16 patients were 7.8(range, 6-9) and 5.8(range, 3 - 10) before surgery and 2.2(range, 0 - 5)and 12.3(range, 9 - 15) at the time of last follow up. Both VAS and JOA score improved significantly after the surgery (p<0.05, t-test). All patients improved after the operation and no revision surgery was required. No metal failure or pseudoarthrosis was observed during the follow-up. The success rate was 87.5%. Conclusion: Our data suggest that unilateral decompression and pedicle screw fixation for the unilateral symptomatic foraminal stenosis is an effect method for obtaining satisfactory clinical outcome. Its possible advantage is shorter operation time and reduced surgical extent. We believe that the reduced stiffness of unilateral fixation was compensated by pedicle screw augmentation and interbody fusion.

• Journal of Korean Neurosurgical Society
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• 제30권11호
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• pp.1271-1277
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• 2001

Objectives : Since vertebroplasty has been introduced, we performed short segment pedicle screw fixation with augmented intra-operative vertebroplasty in patients with unstable thoraco-lumbar fracture. Our intentions are to demonstrate the efficacy and indication of this new technique compare to conventional methods. Material and Methods : The surgery comprised of pedicle screw fixations on one level above and below the fracture site, and the fractured level itself, if pedicle is intact, and intra-operative vertebroplasty under the fluoroscopic guide with in-situ postero-lateral bone graft. Also, in cases of bone apposition, we removed those with small impactor through a transfascetal route. During the last 2 years, we performed in seven(7) unstable thoraco-lumbar fracture patients who consisted of two different characteristics, those four(4) with primary or secondary osteoporosis and three(3) of young and very healthy. All patients were followed clinically by A.S.I.A. score and radiography. Results : Mean follow up period was 14 months. We observed well decompressed state via transfascetal route in cases of bone fragments apposition and no hardware pullout in osteoporotic cases, no poly-methyl-methacrylate (PMMA) leakage through the fracture sites into the spinal canal, and no kyphotic deformities in both cases during follow-up periods. All patients demonstrated solid bony fusion except one following osteoporotic compression fracture on other sites. Conclusions : In the management of unstable thoraco-lumbar fracture, we believe that this short segment pedicle screw fixation with augmented intra-operative vertebroplasty reduce the total length or levels of pedicle screw fixation without post-operative kyphotic deformity.

• Archives of Reconstructive Microsurgery
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• 제21권2호
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• pp.86-91
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• 2012

Purpose: Mass can compress around tissue and cause deviation of normal anatomical structures. Often, mass grows toward neurovascular pedicle and encircles depending on the nature of mature mass. Neglecting neurovascular involvement of the mass is a serious problem not to be overlooked. Authors have performed microscopic approach regarding mass involving the neurovascular pedicle in the hand. Materials and Methods: From January 2007 through February 2012, retrospective analysis for nine cases of mass involving neurovascular pedicles was done. Patients were evaluated preoperatively by ultrasonography or MRI and checked intraoperative finding. Masses were evaluated by site, preoperative evaluation, involved neurovascular pedicle, histopathologic diagnosis, complication, and recurrence. Results: The site of mass involving neurovascular pedicles was 4 cases on the wrist, 2 cases on the palm, 2 cases on the finger, 1 case on the hand dorsum. Involved neurovascular pedicles were 3 radial arteries and nerves, 3 proper digital arteries and nerves, 1 radial artery, 1 superficial branch of radial nerve, 1 common digital artery and nerve. The histopathologic diagnosis of mass were 3 ganglions, 2 giant cell tumors, 2 epidermal cysts, 1 fibroma, and 1 benign spindle tumor. There were 2 cases of recurrence and secondary excisions were performed. Conclusion: Neurovascular pedicle injury can lead to serious complication like sensory and motor disorders, distal part ischemia, and so on. In case of mass suspected neurovascular invasion, accurate preoperative evaluation such as ultrasonography or MRI is necessary. To prevent any neurovascular related complication during mass excision, delicate surgical technique using a microscope becomes essential.

• Archives of Plastic Surgery
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• 제33권3호
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• pp.276-282
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• 2006

The anterolateral thigh(ALT) flap has been known as a very versatile and reliable flap. We report our experiences with the anterolateral thigh flap for the postoncologic reconstruction of head and neck region from April 2002 to March 2005. A total of 38 subjects (M: F=30:8, mean age:53.8 years) were taken. We reviewed primary site of tumors, size and thickness of flaps, location and number of perforators, course of perforators, length of pedicle, and postoperative complications. The mean flap size, thickness and pedicle length were $11.8{\times}6.4cm$, 1.1 cm and 12.2 cm, respectively. We classified the pedicles based on the authors' criteria. Type I, pedicle with short intramuscular course, was with 29 cases(72.5%), type II, pedicle with long intramuscular course, with 6 cases(15%), type III, pedicle with septocutaneous course, with 3 cases(7.5%), and type IV, clinically unavailable pedicle, with 2 cases (5%). We experienced 1 case of partial and 1 case of total flap loss. There was 1 case of donor site wound dehiscence, which was treated by debridement and closure. According to the defect, efficient adjustment of the size and thickness of flap was possible, and favorable functional and aesthetic results have been obtained in our study. Our experience confirmed the versatility and usefulness of the anterolateral thigh flap for various reconstructions in head and neck region.

• 한국산학기술학회논문지
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• 제12권4호
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• pp.1775-1780
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• 2011

본 논문은 요추부의 손상이 심할 경우 척추경 나사시스템이라는 인공물을 이용하여 수술을 하게 되는데, 이때 적용되는 척추경 나사시스템의 역학특성을 분석하였다. 척추경 나사 시스템으로 고정된 디스크는 일반적으로 퇴행되지만, 제안된 플렉시블 로드를 적용할 경우 고정된 디스크에 유연성(6도 이하)을 부여할 수 있어 디스크가 퇴행되는 것을 막아주는 역할을 할 수 있다. 본 연구에서는 유한요소 해석을 이용하여 플렉시블 로드를 적용한 척추경 나사 시스템의 역학특성을 분석한 결과, 10N 이하의 척추 거동에서 플렉서블 로드는 항복 응력 이내의 응력 분포가 나타남을 알 수 있었으며. 분석된 플렉시블 로드 시스템은 실제 제작 후 인장, 압축 비틀림 등의 척추경 나사 시스템 공인 규격 실험(ASTM F 1717)을 수행하여 항복 응력 이내의 안정적인 작동성을 검증하였다.

• Journal of Korean Neurosurgical Society
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• 제52권4호
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• pp.359-364
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• 2012

Objective : Transpedicular screw fixation has some disadvantages such as postoperative back pain through wide muscle dissection, long operative time, and cephalad adjacent segmental degeneration (ASD). The purposes of this study are investigation and comparison of radiological and clinical results between interspinous fusion device (IFD) and pedicle screw. Methods : From Jan. 2008 to Aug. 2009, 40 patients underwent spinal fusion with IFD combined with posterior lumbar interbody fusion (PLIF). In same study period, 36 patients underwent spinal fusion with pedicle screw fixation as control group. Dynamic lateral radiographs, visual analogue scale (VAS), and Korean version of the Oswestry disability index (K-ODI) scores were evaluated in both groups. Results : The lumbar spine diseases in the IFD group were as followings; spinal stenosis in 26, degenerative spondylolisthesis in 12, and intervertebral disc herniation in 2. The mean follow up period was 14.24 months (range; 12 to 22 months) in the IFD group and 18.3 months (range; 12 to 28 months) in pedicle screw group. The mean VAS scores was preoperatively $7.16{\pm}2.1$ and $8.03{\pm}2.3$ in the IFD and pedicle screw groups, respectively, and improved postoperatively to $1.3{\pm}2.9$ and $1.2{\pm}3.2$ in 1-year follow ups (p<0.05). The K-ODI was decreased significantly in an equal amount in both groups one year postoperatively (p<0.05). The statistics revealed a higher incidence of ASD in pedicle screw group than the IFD group (p=0.029) Conclusion : Posterior IFD has several advantages over the pedicle screw fixation in terms of skin incision, muscle dissection and short operative time and less intraoperative estimated blood loss. The IFD with PLIF may be a favorable technique to replace the pedicle screw fixation in selective case.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2009년도 추계학술대회 논문집
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• pp.619-620
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• 2009

• Journal of Korean Neurosurgical Society
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• 제62권4호
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• pp.376-381
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• 2019

Objective : To define optimal method that calculate the safe direction of cervical pedicle screw placement using computed tomography (CT) image based three dimensional (3D) cortical shell model of human cervical spine. Methods : Cortical shell model of cervical spine from C3 to C6 was made after segmentation of in vivo CT image data of 44 volunteers. Three dimensional Cartesian coordinate of all points constituting surface of whole vertebra, bilateral pedicle and posterior wall were acquired. The ideal trajectory of pedicle screw insertion was defined as viewing direction at which the inner area of pedicle become largest when we see through the biconcave tubular pedicle. The ideal trajectory of 352 pedicles (eight pedicles for each of 44 subjects) were calculated using custom made program and were changed from global coordinate to local coordinate according to the three dimensional position of posterior wall of each vertebral body. The transverse and sagittal angle of trajectory were defined as the angle between ideal trajectory line and perpendicular line of posterior wall in the horizontal and sagittal plane. The averages and standard deviations of all measurements were calculated. Results : The average transverse angles were $50.60^{\circ}{\pm}6.22^{\circ}$ at C3, $51.42^{\circ}{\pm}7.44^{\circ}$ at C4, $47.79^{\circ}{\pm}7.61^{\circ}$ at C5, and $41.24^{\circ}{\pm}7.76^{\circ}$ at C6. The transverse angle becomes more steep from C3 to C6. The mean sagittal angles were $9.72^{\circ}{\pm}6.73^{\circ}$ downward at C3, $5.09^{\circ}{\pm}6.39^{\circ}$ downward at C4, $0.08^{\circ}{\pm}6.06^{\circ}$ downward at C5, and $1.67^{\circ}{\pm}6.06^{\circ}$ upward at C6. The sagittal angle changes from caudad to cephalad from C3 to C6. Conclusion : The absolute values of transverse and sagittal angle in our study were not same but the trend of changes were similar to previous studies. Because we know 3D address of all points constituting cortical shell of cervical vertebrae. we can easily reconstruct 3D model and manage it freely using computer program. More creative measurement of morphological characteristics could be carried out than direct inspection of raw bone. Furthermore this concept of measurement could be used for the computing program of automated robotic screw insertion.

• Journal of Korean Neurosurgical Society
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• 제66권1호
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• pp.44-52
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• 2023

Objective : This study aimed to investigate the efficacy of transverse process (TP) hook system at the upper instrumented vertebra (UIV) for preventing screw pullout in adult spinal deformity surgery using the pedicle Hounsfield unit (HU) stratification based on K-means clustering. Methods : We retrospectively reviewed 74 patients who underwent deformity correction surgery between 2011 and 2020 and were followed up for >12 months. Pre- and post-operative data were used to determine the incidence of screw pullout, UIV TP hook implementation, vertebral body HU, pedicle HU, and patient outcomes. Data was then statistically analyzed for assessment of efficacy and risk prediction using stratified HU at UIV level alongside the effect of the TP hook system. Results : The screw pullout rate was 36.4% (27/74). Perioperative radiographic parameters were not significantly different between the pullout and non-pullout groups. The vertebral body HU and pedicle HU were significantly lower in the pullout group. K-means clustering stratified the vertebral body HU ≥205.3, <137.2, and pedicle HU ≥243.43, <156.03. The pullout rate significantly decreases in patients receiving the hook system when the pedicle HU was from ≥156.03 to < 243.43 (p<0.05), but the difference was not statistically significant in the vertebra HU stratified groups and when pedicle HU was ≥243.43 or <156.03. The postoperative clinical outcomes improved significantly with the implementation of the hook system. Conclusion : The UIV hook provides better clinical outcomes and can be considered a preventative strategy for screw-pullout in the certain pedicle HU range.