Inufusa A, An H S, Lim T H, Hasegawa T, Haughton V M, Nowicki B H
Department of Orthopaedic Surgery, Medical College of Wisconsin, Milwaukee, USA.
Spine (Phila Pa 1976). 1996 Nov 1;21(21):2412-20. doi: 10.1097/00007632-199611010-00002.
A cadaveric study was done to analyze the dimensional changes in the spinal canal and intervertebral foramen of the lumber spine with flexion and extension movements.
To investigate the relationship between flexion and extension movements and morphologic changes in the spinal canal and the intervertebral foramen.
Previous studies have reported that the dimensions of the spinal canal and the intervertebral foramen may change significantly with motion. The purpose of this study was to assess the quantitative changes in the spinal canal and the intervertebral foramen with segmental flexion-extension movements.
Nineteen fresh cadaveric spines yielding 25 motion segments were used. The lumbar motion segments were frozen and then imaged in axial and sagittal projections by a computed tomography scanner. They were thawed then, and the motion segments were loaded to 5.7 Nm in flexion (13 motion segments) and in extension (12 motion segments) specimens. While in flexion or extension, the specimens again were frozen and imaged by computed tomography scan. The frozen specimens than were sliced using a cryomicrotome in the sagittal plane to study the dimensions of the intervertebral foramen. Eighteen other fresh cadaveric spines were sliced sagittally for study in the neutral position.
The axial computed tomography scans showed that extension significantly decreased the canal area, midsagittal diameter, and subarticular sagittal diameter, whereas flexion had the opposite effects. The sagittal computed tomography scans showed that extension decreased all the foraminal dimensions significantly, whereas flexion increased all the foraminal dimensions significantly. The translational changes were associated with the bulging of the disc and the presence of traction spurs. The cryomicrotome sections showed the cross-sectional area of the foramen to be 12% greater for the flexion group and 15% smaller for the extension group than the cross-sectional area of the neutral group. Nerve root compression in the foramen was found to be 21.0% in neutral, 15.4% in flexion, and 33.3% in extension groups.
The study supports the concept of dynamic spinal stenosis. In addition to static anatomic changes, careful dynamic studies may be required to evaluate better the central canal and the foramen.
进行了一项尸体研究，以分析腰椎在屈伸运动时椎管和椎间孔的尺寸变化。
探讨屈伸运动与椎管及椎间孔形态变化之间的关系。
先前的研究报道，椎管和椎间孔的尺寸可能会随运动而发生显著变化。本研究的目的是评估节段性屈伸运动时椎管和椎间孔的定量变化。
使用了19个新鲜尸体脊柱，共得到25个运动节段。将腰椎运动节段冷冻，然后通过计算机断层扫描仪进行轴向和矢状面成像。然后将其解冻，对运动节段在屈曲（13个运动节段）和伸展（12个运动节段）标本中施加5.7 Nm的负荷。在屈曲或伸展时，再次将标本冷冻并通过计算机断层扫描成像。然后使用冷冻切片机在矢状面将冷冻标本切片，以研究椎间孔的尺寸。另外18个新鲜尸体脊柱在矢状面切片，用于中立位研究。
轴向计算机断层扫描显示，伸展显著减小了椎管面积、矢状径和关节下矢状径，而屈曲则产生相反的效果。矢状面计算机断层扫描显示，伸展显著减小了所有椎间孔尺寸，而屈曲则显著增加了所有椎间孔尺寸。平移变化与椎间盘突出和牵引性骨刺的存在有关。冷冻切片显示，屈曲组椎间孔的横截面积比中立组大12%，伸展组比中立组小15%。发现椎间孔神经根受压在中立组为21.0%，屈曲组为15.4%，伸展组为33.3%。
该研究支持动态性椎管狭窄的概念。除了静态解剖学变化外，可能还需要进行仔细的动态研究，以更好地评估中央管和椎间孔。
