• 대한의용생체공학회:의공학회지
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• 제38권1호
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• pp.9-15
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• 2017

Recently, flexible cages have been introduced in an attempt to absorb and reduce the abnormal load transfer along the anterior parts of the spine. They are designed to be used with the pedicle screw systems to allow some mobility at the index level while containing ROM at the adjacent level. In this study, a finite element (FE) study was performed to assess biomechanical efficacies of the flexible cage when combined with pedicle screws with flexible rods. The post-operated models were constructed by modifying the L4-5 of a previously-validated 3-D FE model of the intact lumbar spine (L2-S1): (1) Type 1, flexible cage only; (2) Type 2, pedicle screws with flexible rods; (3) Type 3, interbody fusion cage plus pedicle screws with rigid rods; (4) Type 4, interbody fusion cage plus Type 2; (5) Type 5, Type 1 plus Type 2. Flexion/extension of 10 Nm with a compressive follower load of 400N was applied. As compared to the Type 3 (62~65%) and Type 4 (59~62%), Type 5 (53~55%) was able to limit the motion at the operated level effectively, despite moderate reduction at the adjacent level. It was also able to shift the load back to the anterior portions of the spine thus relieving excessively high posterior load transfer and to reduce stress on the endplate by absorbing the load with its flexible shape design features. The likelihood of component failure of flexble cage remained less than 30% regardless of loading conditions when combined with pedicle screws with flexible rods. Our study demonstrated that flexible cages when combined with posterior dynamic system may help reduce subsidence of cage and degeneration process at the adjacent levels while effectively providing stability at the operated level.

• Composites Research
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• 제25권4호
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• pp.98-104
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• 2012

본 논문에서는 척추체 간 유합용 케이지의 응력방패현상을 감소시키기 위하여 강성 차이에 대한 연구를 수행하였다. 최근 의료 임플란트 분야에서는 탄소섬유강화 폴리머를 이용하여 좋은 결과를 보여 왔다. 그러나 생체 역학적으로 이 재료에 대하여 요추체의 안정성과 골 이식재가 받는 응력에 관련한 연구는 없었다. 따라서 이전에 유효화한 요추체 (L2-L5) 비선형 유한 요소 모델을 이용하여 L4-L5 분절의 케이지의 강성 차이에 따른 효과를 알아보기 위하여 탄소섬유강화 폴리머와 티타늄 케이지를 이용한 후방 요추체 유합 모델을 만들었다. 자가골 보다 강성이 작은 탄소 섬유강화폴리머 케이지는 인접 분절의 하종판에 응력이 적게 걸리며, 골 이식재에 응력은 증가시켰다. 위의 결과로 탄소섬유강화 폴리머 케이지는 응력 방패 현상을 감소시킬 수 있을 뿐만 아니라 골 유합률을 증가시킬 수 있다.

• 대한의용생체공학회:의공학회지
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• 제26권3호
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• pp.151-155
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• 2005

Interspinous spacers have been developed as an alternative surgical treatment for laminectomy or fusion with pedicle screws and rods for the treatment of lumbar spinal stenosis. However, its biomedical efficacies are well not known. In this study, we evaluated kinematic behaviors of the surgical and the adjacent levels before and after inserting interspinous spacers. Three porcine lumbar spines were prepared. On each specimen, an interspinous spacer was inserted at the L4-L5. Flexion-extension moments (0, 2.5, 5.0, 7.5, 10Nm) were applied. A stereophotogrammetric set-up with DLT algorithm was used to assess the three-dimensional motions of the specimen where three markers $({\square}0.8mm)$ were attached to each vertebra. Results showed that extension motion decreased by $15-24\%$ at the surgical level (L4-L5) after insertion of interspinous spacer. At the adjacent levels, the range of motion remained unchanged. In flexion, no significant changes in motion were observed regardless of levels. Therefore, our experimental results demonstrated the interspinous spacer is very effective in limiting the extension motion that may cause narrowing of the spinal canal and vertebral foramen while maintaining kinematic behaviors at the adjacent levels. Further, these results suggested that the use of interspinous spacer may be able to prevent lower back pain at the surgical level and to lower the incidence of degenerative changes at the adjacent levels.

• Clinics in Orthopedic Surgery
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• 제10권4호
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• pp.508-512
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• 2018

Foraminal decompression using a minimally invasive technique to preserve facet joint stability and function without fusion reportedly improves the radicular symptoms in approximately 80% of patients and is considered one of the good surgical treatment choices for lumbar foraminal or extraforaminal stenosis. However, proper decompression was not possible because of the inability to access the foramen at the L5-S1 level due to prominence of the iliac crest. To overcome this challenge, endoscopy-based minimally invasive spine surgery has recently gained attention. Here, we report the technical skills required in unilateral extraforaminal biportal endoscopic spinal surgery using a $30^{\circ}$ arthroscope to enable foraminal decompression at the L5-S1 level. Two 0.8-cm portals were created 2 cm lateral from the lateral border of the pedicles at the L5-S1 level. After sufficient working space was made, half of the superior articular process (SAP) in the hypertrophied facet joint was removed using a high-speed burr and a 5-mm wide osteotome, whereas the remaining inside part of the SAP was removed using a Kerrison punch and pituitary punch. The foraminal ligamentum flavum should be removed to inspect the conditions of the L5 exiting root and disc. Removing of the extruded disc could decompress the L5 root. The extraforaminal approach using a $30^{\circ}$ arthroscope is considered a minimally invasive alternative technique for decompressing foraminal stenosis at the L5-S1 level that preserves facet stability and provides symptomatic relief.

• Journal of Korean Neurosurgical Society
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• 제51권2호
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• pp.81-85
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• 2012

Objective : The purpose of this prospective study was to evaluate the effects of body mass index (BMI) on intra-abdominal pressure (IAP) and intraoperative blood loss (IBL) during lumbar spinal surgery. Methods : Thirty patients scheduled for single level posterior lumbar interbody fusion were allocated equally to a normal group (Group 1, BMI;$18.5-22.9kg/m^2$), an overweight group (Group 2, BMI; $23-24.9kg/m^2$), and an obese group (Group 3, BMI; $25.0-29.9kg/m^2$) according to BMI. IAP was measured using a urinary bladder catheter; 1) supine after anesthesia induction, 2) prone at skin incision, 3) prone at the end of surgery. In addition, IBL was also measured in the three groups. Results : IAP in the supine position was not significantly different in groups 1, 2, and 3 (2.7 mm Hg, 3.0 mm Hg, and 4.2 mm Hg, respectively) ($p$=0.258), and IAP in the prone position at incision increased to 7.8 mm Hg, 8.2 mm Hg, and 10.4 mm Hg, respectively, in the three groups, and these intergroup differences were significant, especially for Group 3 ($p$=0.000). IAP at the end of surgery was slightly lower (7.0 mm Hg, 7.7 mm Hg, and 9.2 mm Hg, respectively). IBLs were not significantly different between the three groups. However, IBLs were found to increase with IAP in the prone position ($p$=0.022) and BMI ($p$<0.05). Conclusion : These results show that BMI affects IAP in the prone position more than in the supine position during lumbar spinal surgery. In addition, IBLs were found to increase with IAP in the prone position and with BMI. Thus, IBLs can be expected to be higher in morbidly obese patients due to an increased IAP.

• Journal of Korean Neurosurgical Society
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• 제57권6호
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• pp.484-486
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• 2015

Unilateral pedicle stress fracture accompanying spondylolytic spondylolisthesis is rare even in the elderly. Most are associated with major trauma, previous spine surgery, or stress-related activity. Here, the authors describe an unique case of unilateral pedicle fracture associated with spondylolytic spondylolisthesis at the L5 level, which was successfully treated by posterior lumbar interbody fusion with screw fixation at the L5-S1 level. As far as the authors' knowledge, no such case has been previously reported in the literature. The pathophysiological mechanism of this uncommon entity is discussed and a review of relevant literature is included.

• Journal of Korean Neurosurgical Society
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• 제62권1호
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• pp.61-70
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• 2019

Objective : Corpectomy of the first lumbar vertebra (L1) for the management of different L1 pathologies can be performed using either an anterior or posterior approach. The aim of this study was to evaluate the usefulness of a retroperitoneal extrapleural approach through the twelfth rib for performing L1 corpectomy. Methods : Thirty consecutive patients underwent L1 corpectomy between 2010 and 2016. The retroperitoneal extrapleural approach through the 12th rib was used in all cases to perform single-stage anterior L1 corpectomy, reconstruction and anterior instrumentation, except for in two recurrent cases in which posterior fixation was added. Visual analogue scale (VAS) was used for pain intensity measurement and ASIA impairment scale for neurological assessment. The mean follow-up period was 14.5 months. Results : The sample included 18 males and 12 females, and the mean age was 40.3 years. Twenty patients (67%) had sensory or motor deficits before the surgery. The pathologies encountered included traumatic fracture in 12 cases, osteoporotic fracture in four cases, tumor in eight cases and spinal infection in the remaining six cases. The surgeries were performed from the left side, except in two cases. There was significant improvement of back pain and radicular pain as recorded by VAS. One patient exhibited postoperative neurological deterioration due to bone graft dislodgement. All patients with deficits at least partially improved after the surgery. During the follow-up, no hardware failures or losses of correction were detected. Conclusion : The retroperitoneal extrapleural approach through the 12th rib is a feasible approach for L1 corpectomy that can combine adequate decompression of the dural sac with effective biomechanical restoration of the compromised anterior loadbearing column. It is associated with less pulmonary complication, no need for chest tube, no abdominal distention and rapid recovery compared with other approaches.

• Journal of Korean Neurosurgical Society
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• 제62권4호
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• pp.432-441
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• 2019

Objective : Few studies have reported direct comparative data of lumbar spine angles between direct lateral interbody fusion (DLIF) and oblique lateral interbody fusion (OLIF). The purpose of this study was to investigate the clinical and radiological outcomes of DLIF and OLIF, and determine influential factors. Methods : The same surgeon performed DLIF from May 2011 to August 2014 (n=201) and OLIF from September 2014 to September 2016 (n=142). Radiological parameters, cage height, cage angle (CA), cage width (CW), and cage location were assessed. We checked the cage location as the distance (mm) from the anterior margin of the disc space to the anterior metallic indicator of the cage in lateral images. Results : There were significant differences in intervertebral foramen height (FH; $22.0{\pm}2.4$ vs. $21.0{\pm}2.1mm$, p<0.001) and sagittal disc angle (SDA; $8.7{\pm}3.3$ vs. $11.3{\pm}3.2^{\circ}$, p<0.001) between the DLIF and OLIF groups at 7 days postoperatively. CA ($9.6{\pm}3.0$ vs. $8.1{\pm}2.9^{\circ}$, p<0.001) and CW ($21.2{\pm}1.6$ vs. $19.2{\pm}1.9mm$, p<0.001) were significantly larger in the OLIF group compared to the DLIF group. The cage location of the OLIF group was significantly more anterior than the DLIF group ($6.7{\pm}3.0$ vs. $9.1{\pm}3.6mm$, p<0.001). Cage subsidence at 1 year postoperatively was significantly worse in the DLIF group compared to the OLIF group ($1.0{\pm}1.5$ vs. $0.4{\pm}1.1mm$, p=0.001). Cage location was significantly correlated with postoperative FH (${\beta}=0.273$, p<0.001) and postoperative SDA (${\beta}=-0.358$, p<0.001). CA was significantly correlated with postoperative FH (${\beta}=-0.139$, p=0.044) and postoperative SDA (${\beta}=0.236$, p=0.001). Cage location (${\beta}=0.293$, p<0.001) and CW (${\beta}=-0.225$, p<0.001) were significantly correlated with cage subsidence. Conclusion : The cage location, CA, and CW seem to be important factors which result in the different-radiological outcomes between DLIF and OLIF.

• 대한한의학회지
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• 제37권2호
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• pp.93-103
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• 2016

Objectives: The purpose of this study was to report Four cases of Failed Back Surgery Syndrome (FBSS) patients after spinal fusion surgery who showed significant improvement in pain and function with Complex Korean medical treatment. Methods: This study was a retrospective observational study. We reviewed medical records of Four patients with lumbar pain or radiating leg pain, who have received spinal fusion surgery in the past. All Four patients took complex treatments of Mokhuri Neck and Back hospital which involes Acupuncture, Pharmaco-acupuncture, Gangchuk herbal medicine, Chuna and Physical therapy during about four-week of admission treatment. Visual Analogue Scale (VAS), Oswestry disability index (ODI), Pain Free Walking Distance (PFWD) scores were assessed before and after treatments. Results: The average of hospitalization period was 28.5 days. Mean VAS scores decreased from 6.5 to 2.3, Oswestry Disability Index (ODI) scores decreased from 56.25 to 38.25 and Pain Free Walking Distance (PFWD) also improved from 10m to 166.6m. Conclusion: This study implies that a combination of Korean medical treatments might be effective in relieving pain, and improving the functional status of FBSS patients. Further studies are needed to fully understand the mechanisms underlying the effects.

• 대한정형외과학회지
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• 제56권5호
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• pp.419-426
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• 2021

목적: 화농성 요추부 추체 감염의 수술적 치료 시 이환된 추체에 척추경 나사를 삽입하는 수술법은 균막의 형성 및 감염 치료 실패의 위험성으로 기피되었다. 저자들은 이환된 추체에 척추경 나사를 삽입하여 고정 분절수를 최소화하면서도 감염 치료에 성공하였는바, 이를 분석하여 해당 술식의 유용성에 대하여 알아보고자 하였다. 대상 및 방법: 2000년 1월부터 2018년 6월까지 본원 척추센터에서 제1저자에 의해 수술적으로 치료한 화농성 요추부 척추 감염 환자 중, 이환된 추체에 직접 척추경 나사를 삽입하여 유합술을 시행한 환자군을 그룹 A, 이환된 추체 척추경의 골파괴 소견으로 인접 정상 추체에 척추경 나사를 삽입하여 유합술을 시행한 환자군을 그룹B로 분류하여 임상적 결과를 후향적으로 연구하였다. 모든 환자들은 후방 접근법으로 수술하였으며, 이환된 추간판을 제거하고 부골화된 추체의 소파술 및 추체 간 자가 지주골 이식술 후 척추경 나사 고정술을 시행한 48예(그룹A 28예, 그룹B 20예)를 대상으로 두 그룹 간의 입원 기간, 수술 시간, 출혈량 및 수술 후 1개월째 EQ-5D 지수, 주사 항생제 투여 기간, 혈액학적 결과, 임상적 결과, 방사선학적 결과를 종합적으로 분석하였다. 결과: 그룹 A에서 고정 분절 수, 수술 시간, 출혈량 및 술 후 1개월째 EQ-5D 지수에서 그룹 B에 비하여 통계적으로 유의하게 향상된 결과를 보였으며, 항생제 사용 기간, 입원 기간, 방사선학적 골유합의 시기, 시상각의 교정률 및 재발률에서는 유의한 차이를 보이지 않았다. 결론: 후방 도달법을 통한 이환된 추체에 직접 척추경 나사를 삽입하는 최소 분절 고정술은 수술 시간 및 출혈량이 줄어들고, 고정분절을 최소화하여 요추부의 운동성을 보전하면서도, 감염의 확산이나 재발 없이 빠른 회복을 보였기에, 요추부 화농성 척추염 환자의 수술적 치료 시 권장할 만한 술식으로 생각된다.