Background

Studies on the role of uncinate process have been limited to responses of the intact spine and patient's outcomes, and procedures to perform the excision. The aim of this study was to determine the role of uncinate process on the biomechanical response at the index and adjacent levels in three artificial discs used in cervical disc arthroplasty.

Methods

A validated finite element model of cervical spine was used. Flexion, extension, and lateral moments and follower load were applied to Bryan, Mobi-C, and Prestige LP artificial discs at C5-C6 level with and without uncinate process. Ranges of motion at index level and adjacent caudal and cranial segments, intradiscal pressures at adjacent segments, and facet loads at index level and adjacent segments were obtained. Data were normalized with respect to the preservation of uncinate process.

Findings

Uncinate process removal increased motions up to 27% at index and decreased up to 10% at adjacent levels, decreased disc pressures up to 14% at adjacent segments, decreased facet loads at adjacent segments up to 14%, while at index level, change in loads depended on mode and arthroplasty, with Mobi-C responding with up to 51% increase and Bryan disc up to 11% decrease, while Prestige LP increased loads by 17% in extension and decreased by 9%% in lateral bending.

Interpretation

As surgical selection is based on morphology and surgeon's experience, the present computational findings provide quantitative information for an optimal choice of the device and procedure, while further studies (in vitro/clinical) would be required.

中文翻译：

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颈椎间盘置换术中钩突切除的生物力学效应

背景

关于钩突作用的研究仅限于完整脊柱的反应和患者的结果，以及进行切除的程序。本研究的目的是确定钩突对颈椎间盘置换术中使用的三个人工椎间盘在指数和相邻水平的生物力学反应的作用。

方法

使用经过验证的颈椎有限元模型。对 Bryan、Mobi-C 和 Prestige LP 人工椎间盘施加 C5-C6 水平的弯曲、伸展、侧向力矩和随动载荷，有无钩突。获得了指数水平和相邻尾段和颅骨节段的运动范围、相邻节段的椎间盘内压力以及指数水平和相邻节段的小平面载荷。数据根据钩突的保存进行了标准化。

发现

去除钩突的过程在指数处增加了高达 27% 的运动，在相邻的水平上减少了高达 10%，在相邻节段的椎间盘压力降低了高达 14%，在相邻节段的小平面载荷减少了高达 14%，而在指数级，变化载荷取决于模式和关节成形术，Mobi-C 的响应增加高达 51%，Bryan 椎间盘减少高达 11%，而 Prestige LP 的伸展载荷增加了 17%，横向弯曲的载荷减少了 9%。

解释

由于手术选择是基于形态学和外科医生的经验，目前的计算结果为设备和程序的最佳选择提供了定量信息，而需要进一步的研究（体外/临床）。