Brody Michael J, Patel Alpesh A, Ghanayem Alexander J, Wojewnik Bartosz, Carandang Gerard, Havey Robert M, Voronov Leonard I, Vastardis Georgios, Potluri Tejaswy, Patwardhan Avinash G
*Department of Orthopaedic Surgery and Rehabilitation, Loyola University Medical Center, Maywood, IL †Department of Veterans Affairs, Musculoskeletal Biomechanics Laboratory, Edward Hines Jr. VA Hospital, Hines, IL; and ‡Department of Orthopaedic Surgery, Northwestern University School of Medicine, Chicago, IL.
Spine (Phila Pa 1976). 2014 Sep 1;39(19):1558-63. doi: 10.1097/BRS.0000000000000481.
We quantified the segmental biomechanics of a cervical total disc replacement (TDR) before and after progressive posterior decompression. We hypothesized that posterior decompressive procedures would not significantly increase range of motion (ROM) at the index TDR level.
To quantify the kinematics of a cervical total disc replacement (TDR) before and after posterior cervical decompression.
A reported yet unaddressed issue is the potential for the development of same-segment disease after implantation of a cervical TDR and the implications of same-segment posterior decompression on TDR mechanics.
Eight human cadaveric cervical spines C3-C7 were tested in flexion-extension, lateral bending, and axial rotation while intact, after C5-C6 TDR, C5-C6 unilateral foraminotomy, C5-C6 bilateral foraminotomies, and after C5 laminectomy in combination with the bilateral foraminotomies. Moment versus angular motion curves were obtained for each testing step, and the load-displacement data were analyzed to determine the range of angular motion for each step.
Unilateral foraminotomy did not result in a statistically significant increase in flexion-extension ROM, and did not increase the ROM to a degree greater than normal. Although bilateral foraminotomies did increase flexion-extension ROM, motion remained within a physiological range. A full laminectomy added to the bilateral foraminotomies significantly increased ROM and was also associated with distortion of the load-displacement curves.
With respect to segmental biomechanics as demonstrated, we think that for same-segment disease, a unilateral foraminotomy can be performed safely. However, the impact of in vivo conditions was not accounted for in this model, and it is possible that cyclical loading and other physiological stresses on such a construct may affect the behavior and lifespan of the implant in a way that cannot be predicted by a biomechanical study. Bilateral foraminotomies would require close observation and additional clinical follow-up, whereas complete laminectomy combined with bilateral foraminotomies should be avoided after TDR given the significant changes in kinematics. In addition, future disc replacement designs may need to account for changes after posterior decompression for same-segment disease.
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我们对逐步后路减压前后颈椎全椎间盘置换（TDR）的节段生物力学进行了量化。我们假设后路减压手术不会显著增加索引TDR节段的活动范围（ROM）。
量化颈椎后路减压前后颈椎全椎间盘置换（TDR）的运动学。
一个已报道但尚未解决的问题是颈椎TDR植入后同节段疾病发生的可能性以及同节段后路减压对TDR力学的影响。
八具人类尸体颈椎C3-C7在完整状态下、C5-C6 TDR后、C5-C6单侧椎间孔切开术后、C5-C6双侧椎间孔切开术后以及C5椎板切除联合双侧椎间孔切开术后进行屈伸、侧弯和轴向旋转测试。为每个测试步骤获取力矩与角运动曲线，并分析载荷-位移数据以确定每个步骤的角运动范围。
单侧椎间孔切开术并未导致屈伸ROM有统计学意义的增加，且增加的ROM程度未超过正常范围。虽然双侧椎间孔切开术确实增加了屈伸ROM，但运动仍在生理范围内。双侧椎间孔切开术联合全椎板切除术显著增加了ROM，并且还与载荷-位移曲线的变形有关。
就所展示的节段生物力学而言，我们认为对于同节段疾病，可以安全地进行单侧椎间孔切开术。然而，该模型未考虑体内条件的影响，并且这种结构上的周期性加载和其他生理应力可能以生物力学研究无法预测的方式影响植入物的行为和寿命。双侧椎间孔切开术需要密切观察和额外的临床随访，而鉴于运动学的显著变化，TDR后应避免全椎板切除联合双侧椎间孔切开术。此外，未来的椎间盘置换设计可能需要考虑同节段疾病后路减压后的变化。
无。
