Sait Azad, Prabhav Nadipi Reddy, Sekharappa Vijay, Rajan Reshma, Raj N Arunai Nambi, David Kenny Samuel
Spinal Disorders Surgery Unit, Department of Orthopaedics, Christian Medical College, Vellore, Tamil Nadu, India; and.
School of Biosciences and Technology and.
J Neurosurg Spine. 2016 Nov;25(5):602-609. doi: 10.3171/2016.4.SPINE1671. Epub 2016 Jun 10.
OBJECTIVE There has been a transition from long- to short-segment instrumentation for unstable burst fractures to preserve motion segments. Circumferential fixation allows a stable short-segment construct, but the associated morbidity and complications are high. Posterior short-segment fixation spanning one level above and below the fractured vertebra has led to clinical failures. Augmentation of this method by including the fractured level in the posterior instrumentation has given promising clinical results. The purpose of this study is to compare the biomechanical stability of short-segment posterior fixation including the fractured level (SSPI) to circumferential fixation in thoracolumbar burst fractures. METHODS An unstable burst fracture was created in 10 fresh-frozen bovine thoracolumbar spine specimens, which were grouped into a Group A and a Group B. Group A specimens were instrumented with SSPI and Group B with circumferential fixation. Biomechanical characteristics including range of motion (ROM) and load-displacement curves were recorded for the intact and instrumented specimens using Universal Testing Device and stereophotogrammetry. RESULTS In Group A, ROM in flexion, extension, lateral flexion, and axial rotation was reduced by 46.9%, 52%, 49.3%, and 45.5%, respectively, compared with 58.1%, 46.5%, 66.6%, and 32.6% in Group B. Stiffness of the construct was increased by 77.8%, 59.8%, 67.8%, and 258.9% in flexion, extension, lateral flexion, and axial rotation, respectively, in Group A compared with 80.6%, 56.1%, 82.6%, and 121.2% in Group B; no statistical difference between the two groups was observed. CONCLUSIONS SSPI has comparable stiffness to that of circumferential fixation.
目的 对于不稳定爆裂骨折，为保留活动节段，已经从长节段内固定过渡到短节段内固定。环形固定可实现稳定的短节段结构，但相关的发病率和并发症较高。跨越骨折椎体上下各一个节段的后路短节段固定已导致临床失败。通过将骨折节段纳入后路内固定来增强这种方法已取得了有前景的临床结果。本研究的目的是比较胸腰椎爆裂骨折中包括骨折节段的短节段后路固定（SSPI）与环形固定的生物力学稳定性。方法 在10个新鲜冷冻的牛胸腰椎脊柱标本上制造不稳定爆裂骨折，将其分为A组和B组。A组标本采用SSPI进行内固定，B组采用环形固定。使用万能测试装置和立体摄影测量法记录完整标本和内固定标本的生物力学特性，包括活动范围（ROM）和载荷 - 位移曲线。结果 A组中，与B组分别为58.1%、46.5%、66.6%和32.6%相比，前屈、后伸、侧屈和轴向旋转时的ROM分别降低了46.9%、52%、49.3%和45.5%。与B组分别为80.6%、56.1%、82.6%和121.2%相比，A组在前屈、后伸、侧屈和轴向旋转时结构的刚度分别增加了77.8%、59.8%、67.8%和258.9%；两组之间未观察到统计学差异。结论 SSPI与环形固定具有相当的刚度。
