The impact of implantation technique on frontal and sagittal alignment in total lumbar disc replacement: a comparison of anterior versus oblique implantation

Abstract

The concept of total lumbar disc replacement (TDR) is gaining acceptance due to good clinical shortterm outcome. Standard implantation is strict anterior, which poses especially above the segment L5/S1 sometimes difficulties due to the vessel configuration. Therefore, oblique implantable TDR have been invented. In oblique implantation the anterior longitudinal ligament (ALL) is only partially resected, with additional partial resection of lateral annulus fibers. This could have an impact on biomechanical properties, which has not been evaluated until now. We therefore compared the standing ap and lateral X-rays pre-and postoperative after anterior and oblique implantation of TDR in segment L4/5. Significant differences between the groups were not found. In both the anterior and oblique group, segmental lordosis showed a significant increase, whereas total lordosis as well as ap balance were unchanged. The absolute segmental lordosis increase was nearly double in the anterior group. In conclusion, both anterior and oblique implanted TDR significantly increase segmental lordosis while retaining total lordosis and ap balance. The segmental increase is lower in the oblique implanted group which is probably due to the remaining ALL. Further studies should evaluate whether this finding has any implication for the long-term outcome.

Treatment of Lumbar Degenerative Disc Disease Using a Novel, Compressible Core Prosthesis: 24-Month Results

“…Cakir et al [26] studied segmental and overall lordosis after implantation of the ProDisc in 29 patients and similarly found an increase (average of 8.4°) in segmental lordosis. Several other authors, reporting on clinical or biomechanical studies of segmental lordosis changes after TDR with a variety of implants [27][28][29][30][31], similarly found significant increases in segmental lordosis. Since the sagittal balance is either unchanged or improved, the increase in angle after TDR is likely restorative.…”

The Effects of a Semiconstrained Integrated Artificial Disc on Zygapophyseal Joint Pressure and Displacement

“…Despite their various architectural designs, the clinical outcomes of artifi cial disc replacements are unsatisfactory. [24][25][26][27] For instance, components of 2-component prosthesis perform the loading function of the upper and lower soleplates, respectively, forming a self-constrained articular facet, however, sacrifi cing load buffering and the stretching-constraining function of the physiological disc under lumbar rotational motion. Three-component prostheses consist of an upper and lower soleplate along with an elastic core that forms the articular facet of the prosthesis.…”

“…8 , 15-17 , 27 However, 3-component prostheses have comparatively greater motion and do not feature disc-constrained motion, which causes strain on the zygapophyseal joints, resulting in unsatisfactory long-term clinical results. [27][28][29][30] Considering that the therapeutic results of these types of prosthesis do not meet theoretical expectations, disc "fi ber-connecting" mechanisms have gained increased attention. A physiological disc is part of deformable fi brocartilage joint.…”

Effect of Total Lumbar Disc Replacement on Lumbosacral Lordosis

“…D egenerative changes of the lumbar spine results in loss of lumbar lordosis leading to alteration in sagittal balance. 4,[14][15][16][17] In the present study, radiographic measurements of segment and global lordosis were analyzed to assess the effect of lumbar disc replacement on lumbosacral sagittal balance. 1 Decreased lumbar lordosis associated with posterior lumbar interbody fusions may lead to an abnormal sagittal balance, which has been recognized to be associated with persistent postfusion pain.…”