人体下颈椎显微骨硬度体外测量的实验研究

目的 探讨人体下颈椎C₃~C₇椎骨显微骨硬度的分布特征及其临床意义。方法 3具新鲜成人尸体标本,分别为62岁男性(标本A)、45岁女性(标本B)、58岁男性(标本C),由河北医科大学解剖学教研室提供。取其下颈椎C₃~C₇段脊柱,剔除附着软组织。每个椎骨分为椎体区和附件区两部分,使用高精慢速锯分别经椎体中部垂直于椎体上下终板、右侧椎弓根长轴、左侧上下关节突长轴切割3 mm厚骨切片各1片, 并用砂纸打磨,15块椎骨共制成45片骨切片。应用维氏显微硬度测量仪测量骨组织切片不同区域皮质骨和松质骨的显微硬度值,每一个区域选取5个有效显微骨硬度值,全体有效值的平均值作为该区域的硬度值。结果 15块椎骨共计获得825个有效显微骨硬度测量值。 C₃~C₇总体骨硬度值为11.10～47.80 HV,其中皮质骨为(26.04±4.84) HV、松质骨为(22.92±4.78) HV。椎体区皮质骨硬度值为(25.46±4.86) HV、松质骨硬度值为(21.10±4.97) HV,附件区皮质骨硬度值为(26.50±4.78) HV、松质骨硬度值为(24.75±3.80) HV,附件区高于椎体区,差异均有统计学意义(t=2.800、4.978, P值均＜0.05)。3具尸体标本各自的下颈椎在不同部位的骨显微硬度值不同,但椎体区的皮质骨与松质骨骨硬度值均低于附件标本的皮质骨与松质骨骨硬度,其中松质骨之间的差异均有统计学意义(t_A=4.316、t_B=2.364、t_C=2.107, P值均＜0.05);而皮质骨中,仅标本B的差异有统计学意义(t=2.498,P＜0.05)。C₃~C₇各椎骨不同部位的硬度值分布规律与总体一致:椎体区的骨硬度值均低于附件区;其中C₃、C₅、C₆、C₇松质骨的骨硬度值差异具有统计学意义(P值均＜0.05)。 附件分区中,上关节突皮质骨骨硬度低于椎弓根、椎板、横突、下关节突皮质骨骨硬度,差异具有统计学意义(F=8.590, P＜0.05);椎体分区中,下终板皮质骨骨硬度高于上终板和外周终板皮质骨骨硬度,差异具有统计学意义(F=16.365, P＜0.05)。结论 下颈椎椎骨不同部位、不同区域的骨显微硬度存在差异,附件区的皮质骨/松质骨骨硬度分别高于椎体区的皮质骨/松质骨骨硬度。该分布规律是人体活动过程中适应应力应变的生理改变,可以为三维有限元分析、3D打印及术前模拟提供数据支持。

Measurement of micro-hardness of the human lower cervical vertebrae in vitro

Objective To measure and analyze the distribution and significance of the microhardness of the lower cervical vertebrae.Methods The three fresh adult cadaver C₃-C₇ vertebrae specimens were selected and the soft tissue was removed . Each vertebra was divided into a vertebral body area and an attachment area, and then was cut into three 3 mm-thickness slices (1 in the vertebral body area and 2 in the attachment area) by a high-precision slow saw. A total of 45 bone slices were cut from 15 vertebrae. The Vickers method was used to measure the microhardness values of cortical bone and cancellous bone in different areas of bone sections. Five effective microhardness values were selected for each region, and the average value of all effective values was used to be the hardness value of the region.Results A total of 825 effective hardness values were performed on 15 vertebrae. The hardness range of C₃-C₇ was (11.10-47.80)HV. The hardness of cortical bone and cancellous bone were (26.04±4.84)HV and(22.92±4.78)HV, respectively. The hardness of cortical bone and cancellous bone in the vertebral body area were (25.46±4.86)HV and (21.10±4.97)HV,respectively. The hardness of cortical bone and cancellous bone in the attachment area were (26.50±4.78)HV and (24.75±3.80)HV, respectively. The bone hardness of the cortical bone/ cancellous bone in the attachment area was higher than that of the cortical bone/ cancellous bone in the vertebral body area,and the difference was statistically significant(t=2.800, 4.978, P＜0.05). The microhardness values of the lower cervical vertebrae of three cadavers in different regions were different, but the hardness values of the cortical bone and cancellous bone in the vertebral body area were significantly lower than those in the attachment area. The differences of the hardness in cancellous bone were statistically significant(t_A=4.316, t_B=2.364, t_C=2.107, P＜0.05),while in the cortical bone,only Donor B was statistically significant(t=2.498, P＜0.05). The distribution of the hardness values in different regions of each vertebrae was consistent with the whole:the hardness value of the vertebral body area was lower than those of the attachment area.The differences of the cancellous bone in C₃, C₅, C₆ and C₇ were statistically significant(t=3.220, P＜0.05). In the accessory area,the hardness of the superior articular process was significantly lower than those of other regions (F=8.590, P＜0.05); in the vertebral body area,the hardness of the lower endplate was significantly higher than those of other regions (F=16.365, P＜0.05).Conclusions This study reveals that the microhardness of bone in different regions of the lower cervical vertebrae are different.The bone hardness of the cortical bone/cancellous in the attachment area is higher than that in the vertebral body area. This distribution law is a physiological change which adapts to the stress and strain during the human daily activities. It can provide data support for the modeling of the finite element analysis, 3D printing and preoperative simulation.