Guérin Patrick, Obeid Ibrahim, Bourghli Anouar, Masquefa Thibault, Luc Stéphane, Gille Olivier, Pointillart Vincent, Vital Jean-Marc
Laboratoire d'Anatomie Médico-Chirurgicale Appliquée Université Victor Segalen Bordeaux 2, 146 rue Léo Saignat, 33000, Bordeaux, France.
Surg Radiol Anat. 2012 Mar;34(2):151-7. doi: 10.1007/s00276-011-0881-z. Epub 2011 Oct 5.
The minimally invasive transpsoas approach can be employed to treat various spinal disorders, such as disc degeneration, deformity, and lateral disc herniation. With this technique, visualization is limited in comparison with the open procedure and the proximity of the lumbar plexus to the surgical pathway is one limitation of this technique. Precise knowledge of the regional anatomy of the lumbar plexus is required for safe passage through the psoas muscle. The primary objective of this study was to determine the anatomic position of the lumbar plexus branches and sympathetic chain in relation to the intervertebral disc and to define a safe working zone. The second objective was to compare our observations with previous anatomical studies concerning the transpsoas approach.
A total of 60 lumbar plexus in 8 fresh cadavers from the Department of Anatomy were analyzed in this study. Coronal and lateral X-Ray images were obtained before dissection in order to eliminate spine deformity or fracture. All cadavers were placed in a lateral decubitus position with a lateral bolster. Dissection of the lumbar plexus was performed. All nerve branches and sympathetic chain were identified. Intervertebral disc space from L1L2 to L4L5 was divided into four zones. Zone 1 being the anterior quarter of the disc, zone 2 being the middle anterior quarter, zone 3 the posterior middle quarter and zone 4 the posterior quarter. Crossing of each nervous branch with the disc was reported and a safe working zone was determined for L1L2 to L4L5 disc levels. A safe working zone was defined by the absence of crossing of a lumbar plexus branch.
No anatomical variation was found during blunt dissection. As described previously, the lumbar plexus is composed of the ventral divisions of the first four lumbar nerves and from contributions of the sub costal nerve from T12. The safe working zone includes zones 2 and 3 at level L1L2, zone 3 at level L2L3, zone 3 at level L3L4, and zone 2 at level L4L5. No difference was observed between right and left sides as regards the relationships between the lumbar plexus and the intervertebral disc.
We observed some differences concerning the safe working zone in comparison with other cadaveric studies. The small number of cadaveric specimens used in anatomical studies probably explains theses differences. The minimally invasive transpsoas lateral approach was initially developed to reduce the complications associated with the traditional procedure. The anatomical relationships between the lumbar plexus and the intervertebral disc make this technique particularly risky a L4L5. Alternative techniques, such as transforaminal interbody fusion (TLIF), posterior lumbar interbody fusion (PLIF) or anterior interbody fusion (ALIF) should be used at this level.
微创经腰大肌入路可用于治疗各种脊柱疾病，如椎间盘退变、畸形和外侧椎间盘突出症。采用该技术时，与开放手术相比，视野受限，且腰丛靠近手术路径是该技术的一个局限性。为安全穿过腰大肌，需要精确了解腰丛的局部解剖结构。本研究的主要目的是确定腰丛分支和交感神经链相对于椎间盘的解剖位置，并确定一个安全工作区。第二个目的是将我们的观察结果与先前关于经腰大肌入路的解剖学研究进行比较。
本研究分析了解剖学系8具新鲜尸体中的60个腰丛。在解剖前获取冠状位和侧位X线图像，以排除脊柱畸形或骨折。所有尸体均侧卧于外侧垫枕上。对腰丛进行解剖。识别所有神经分支和交感神经链。将L1L2至L4L5的椎间盘间隙分为四个区域。区域1为椎间盘的前四分之一，区域2为中前四分之一，区域3为后中四分之一，区域4为后四分之一。报告每条神经分支与椎间盘的交叉情况，并确定L1L2至L4L5椎间盘水平的安全工作区。安全工作区定义为无腰丛分支交叉。
钝性解剖过程中未发现解剖变异。如前所述，腰丛由第1至4腰神经的腹侧支以及第12胸神经的肋下神经分支组成。安全工作区在L1L2水平包括区域2和3，L2L3水平为区域3，L3L4水平为区域3，L4L5水平为区域2。腰丛与椎间盘之间的关系在左右两侧未观察到差异。
与其他尸体研究相比，我们观察到安全工作区存在一些差异。解剖学研究中使用的尸体标本数量较少可能解释了这些差异。微创经腰大肌外侧入路最初是为减少与传统手术相关的并发症而开发的。腰丛与椎间盘之间的解剖关系使得该技术在L4L5水平特别危险。在此水平应使用替代技术，如经椎间孔椎间融合术（TLIF）、后路腰椎椎间融合术（PLIF）或前路椎间融合术（ALIF）。
