Müller A, Reulen H J
Department of Neurosurgery, Ludwig-Maximilians-University of Munich, Klinikum Grosshadern, Germany.
Neurosurgery. 1998 Oct;43(4):854-61; discussion 861-2. doi: 10.1097/00006123-199810000-00077.
Extraforaminal disc herniations today are operated on via the so-called lateral approach. Clinical experience has shown that in contrast to levels L2/3-L4/5, this approach may become extremely difficult at the L5-S1 level. According to new microanatomic studies, the previous lateral approaches at this level often do not allow access to the neuroforamen without partial or total destruction of the L5-S1 facet joint. Postoperatively, this may lead to joint irritation with consecutive low back and pseudoradicular pain. To preserve the facet joint, a new approach was developed based on an anatomic study.
The approach was first considered with the help of bone specimens including ilium, vertebra 5, and sacrum. Thereafter, lumbar maceration specimens were prepared leaving ligaments, intervertebral discs, and joints intact. From these specimens, bony and ligamentous landmarks were deduced. Finally, the approach was tested on seven cadavers. Subsequently, the approach was performed on 13 patients and the intraoperative findings, the clinical feasibility, and the postoperative results were analyzed.
After a transverse skin incision above the dorsal curvature of the ilium, the paravertebral muscles are dissected from the ilium medially toward the spinous process. Lateral from the apophyseal joint, a canal is drilled through the spongiosa of the sacrum. Primarily, a thin layer of inner cortex is spared to protect the content of the neuroforamen. Subsequently, it can easily be removed with the dissector to enter the extraforaminal space. In the depth of the drilled canal, the nerve root is found, because it is fixed at the sacrum near the disc space by the anterior lumbosacral ligaments. Riding on the nerve root, the intertransverse ligament and muscle can be removed with the punch. It is then possible to see the neuroforamen and extraforaminal space in front of the joint. Free fragments and contained discs can then easily be found and removed.
Using this new approach, the L5-S1 joint remains intact. Space for instrumental manipulations is created in areas not essential for joint function. For this procedure, newly defined anatomic landmarks, such as the ileolumbar ligament, upper edge of the sacrum, lateral rim of the apophyseal joint, and para-articular notch, guide the operative route. In accordance with the preliminary anatomic studies, this approach was successfully used in 13 patients, and we think that it is a promising alternative that helps to preserve joint function and dorsal root ganglion integrity.
如今椎间孔外型椎间盘突出症通过所谓的外侧入路进行手术。临床经验表明，与L2/3 - L4/5节段不同，这种入路在L5 - S1节段可能会变得极其困难。根据新的微观解剖学研究，该节段以前的外侧入路常常在不完全或完全破坏L5 - S1小关节的情况下无法进入神经孔。术后，这可能会导致关节刺激并引发连续性下腰痛和假性神经根痛。为了保留小关节，基于一项解剖学研究开发了一种新的入路。
首先借助包括髂骨、第5腰椎和骶骨的骨骼标本对该入路进行研究。此后，制备腰椎浸软标本，使韧带、椎间盘和关节保持完整。从这些标本中推断出骨骼和韧带标志。最后，在7具尸体上对该入路进行测试。随后，对13例患者实施该入路，并对术中发现、临床可行性和术后结果进行分析。
在髂骨背侧弯曲上方做一横形皮肤切口后，从髂骨内侧向棘突方向解剖椎旁肌。在关节突关节外侧，通过骶骨的松质骨钻一个通道。首先，保留一层薄薄的内皮质以保护神经孔内容物。随后，可用剥离器轻松将其去除以进入椎间孔外间隙。在钻好的通道深处可找到神经根，因为它通过腰骶前韧带固定在椎间盘间隙附近的骶骨处。沿着神经根，可用冲头去除横突间韧带和肌肉。然后可以看到关节前方的神经孔和椎间孔外间隙。然后可以轻松找到并去除游离碎片和突出的椎间盘。
采用这种新入路，L5 - S1关节保持完整。在对关节功能不重要的区域创造了器械操作空间。对于该手术，新定义的解剖标志，如髂腰韧带、骶骨上缘、关节突关节外侧缘和关节旁切迹，可引导手术路径。根据初步解剖学研究，该入路已成功应用于13例患者，我们认为它是一种有前景的替代方法，有助于保留关节功能和背根神经节的完整性。
