• Title, Summary, Keyword: Interspinous

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A Morphometric Study of the Lumbar Interspinous Space in 100 Stanford University Medical Center Patients

  • Jang, Donghwan;Park, Seoungwoo
    • Journal of Korean Neurosurgical Society
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    • v.55 no.5
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    • pp.261-266
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    • 2014
  • Objective : With the increased use of interspinous spacers in the treatment of lumbar stenosis, knowledge of the geometry of the interspinous space is important. To prevent dislodgment of an interspinous spacer, the accurate depth and width of the interspinous space needs to be established to facilitate the best intraoperative selection of correct spacer size. Methods : To determine the depth and width of the interspinous space, two methods are available which utilize plain film and magnetic resonance imaging (MRI). Data analysis of the interspinous depth and width was undertaken in 100 patients. Results : The standard deviations were variable, since skin thickness (zone 1) was altered by sex and age. The difference in the zone 1 distance between adjacent interspinous processes varied according to gender (p<0.05), but was not influenced by age [p=0.32 by analysis of variance between groups (ANOVA)]. Zone 2, the supraspinous, and zone 3, the interspinous ligament depths, comprise the operative working area during insertion of an interspinous spacer. There were no differences with regard to gender or age (p>0.05). For zones 6 and 7, the interspinous distances at the narrowest and widest points, respectively, were found to decrease with the aging process, but the decrease was not statistically significant. There were no differences with regard to gender (p>0.05). Conclusion : This study provides additional information on the interspinous space. This statistical data are valuable for use in the design of interspinous spacers.

Change in Kinematics of the Spine after Insertion of an Interspinous Spacer for the Treatment of the Lumbar Spinal Stenosis

  • Lee H. S.;Moon S. J.;Kwon S. Y.;Jung T. G.;Shin K. C.;Lee K. Y.;Lee S. J.
    • Journal of Biomedical Engineering Research
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    • v.26 no.3
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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.

Development and Evaluation for the Micro-Movement Structure of Interspinous (척추극돌간 미세움직임 재현 보형물의 개발 및 평가)

  • Park, Joon-Sik;Seo, Tae-Il;Bae, Jong-Suk;Yoon, Gil-Sang
    • Transactions of the Korean Society of Machine Tool Engineers
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    • v.15 no.3
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    • pp.127-131
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    • 2006
  • Existing orthopedic implants such as pedicle screw and spinal cage were designed to fix the spinal structure. But, nowadays, physicians want to rehabilitate there original functions. To achieve this request, we studied micro-movable structure for interspinous. As a first step, we designed interspinous structure by 3D CAD to join each spinous processes. Next, we simulate it with various factors such as the thickness of micro-movement structure and the design of clip. At last, we performed static compressive test to satisfy the failure load of 339N and dynamic endurance test of 1.2M cycle. As a result, we developed interspinous implant and did several surgery to evaluated its satisfaction.

Design of the Interspinous Process Fixator Using Biomechanical Analysis for the Treament of Degenerative Lumbar Spinal Stenosis (퇴행성 요추부 척추관 협착증 치료를 위한 극돌기간 고정기구의 설계 및 생체역학적 분석)

  • Heo S.;Son K.;Lee S.J.;Moon B.Y.
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • pp.1963-1966
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    • 2005
  • Degenerative lumbar spinal stenosis(DLSS) is a disease inducing low back pain, leg pain, convulsion, numbness, and neurogenic claudication from compression of nerve root. Intervertebra fixation was reported to increase the degenerative of neighbor region after treatment. Recently, a new surgical technique of inserting a fixator between interspinous processes has been introduced. The purpose of this study is to design of the interspinous process fixator with flexibility to complement the trouble of using fixator in DLSS. This study evaluated the existing fixator through the mechanical test and modified fixators using the finite element analysis(FEA). Displacement, stiffness and Von-Mises stress were found to have similar values to those obtained from the mechanical test and the FEA in the biomechanical loading condition. Effects of variation in length and thickness were investigated to design an optimal fixator.

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Biomechanical Comparison of Spinal Fusion Methods Using Interspinous Process Compressor and Pedicle Screw Fixation System Based on Finite Element Method

  • Choi, Jisoo;Kim, Sohee;Shin, Dong-Ah
    • Journal of Korean Neurosurgical Society
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    • v.59 no.2
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    • pp.91-97
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    • 2016
  • Objective : To investigate the biomechanical effects of a newly proposed Interspinous Process Compressor (IPC) and compare with pedicle screw fixation at surgical and adjacent levels of lumbar spine. Methods : A three dimensional finite element model of intact lumbar spine was constructed and two spinal fusion models using pedicle screw fixation system and a new type of interspinous devices, IPC, were developed. The biomechanical effects such as range of motion (ROM) and facet contact force were analyzed at surgical level (L3/4) and adjacent levels (L2/3, L4/5). In addition, the stress in adjacent intervertebral discs (D2, D4) was investigated. Results : The entire results show biomechanical parameters such as ROM, facet contact force, and stress in adjacent intervertebral discs were similar between PLIF and IPC models in all motions based on the assumption that the implants were perfectly fused with the spine. Conclusion : The newly proposed fusion device, IPC, had similar fusion effect at surgical level, and biomechanical effects at adjacent levels were also similar with those of pedicle screw fixation system. However, for clinical applications, real fusion effect between spinous process and hooks, duration of fusion, and influence on spinous process need to be investigated through clinical study.

Biomechanical Analysis of Lumbar Interspinous Process Fixators (요추부 극돌기간 고정기구의 생체역학적 해석)

  • Heo Soon;Park Jung-Hong;Lee Sung-Jae;Son Kwon
    • Journal of the Korean Society for Precision Engineering
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    • v.23 no.3
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    • pp.195-202
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    • 2006
  • The degenerative lumbar spinal stenosis (DLSS) is a disease inducing low back pain, leg pain, convulsion. numbness, and neurogenic claudication from compression of nerve root. Intervertebra fixation was reported to increase the degeneration of neighbor lesion after treatment. Recently, a new surgical technique of inserting a fixator between interspinous processes has been introduced. The purpose of this study is to design the interspinous process fixator with flexibility to complement the trouble of using fixator in DLSS. This study evaluated the existing fixator through the mechanical test and modified it using the finite element analysis (FEA). The evaluation was based on the displacement, stiffness and von-Mises stress obtained from the mechanical test and calculated from the FEA in the biomechanical loading condition. Effects of variation in length and thickness were investigated to design an optimal fixator. Three prototypes were manufactured using FEA results. Mechanical tests under the biomechanical loading condition were performed to select the best one from these three. The selected fixator increased flexiblity by 32.9%.

The Biomechancial Effects of an Interspinous Spacer Implant on 3-D Motions for the Treatment of Lumbar Spinal Stenosis (요추부 척추관 협착증 치료를 위한 극돌기간 삽입술의 3차원 분석을 통한 생체역학적 효과 분석)

  • 이희성;신규철;문수정;정태곤;이권용;이성재
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • pp.1207-1210
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    • 2004
  • As many humans age, degenerative lumbar spinal stenosis (DLSS) becomes a major cause of lower limb discomfort and disability. By surgical treatment method of DLSS, the existing surgical treatment methods using internal fixation have showed degeneration changes of an adjacent vertebrae and loss of lumbar spine lordosis-kyphosis due to eliminating a motion. For solving the problems of internal fixation, a novel interspinous spacer has been developed to treat DLSS by surgical treatment method. In this study, we evaluated the biomechanical effects of the interspinous spacer on the kinematics of the porcine lumbar spine before and after insertion of the implant. For this purpose, a device that is capable of measuring 3-D motions were built based on direct linear transformation (DLT) algorithm written with MATLAB program. Results showed that in extension, a change of the mean angle between the intact and the implanted specimens at L4-L5 was 1.87 degree difference and the implant reduced the extension range of motion of the L4-L5 (p&lt;0.05). But the range of motion in flexion, axial rotation and lateral bending at the adjacent segments was not statistically affected by the implant. In conclusion, we thought that interspinous spacer may have remedical value for DLSS by flexing human lumbar spine.

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