Anatomical study of the paraspinal approach to the lumbar spine

Abstract

The original description of the paraspinal posterior approach to the lumbar spine was for spinal fusion, especially regarding lumbosacral spondylolisthesis treatment. In spite of the technical details described by Wiltse, exact location of the area where the sacrospinalis muscle has to be split remains somewhat unclear. The goal of this study was to provide topographic landmarks to facilitate this surgical approach. Thirty cadavers were dissected in order to precisely describe the anatomy of the trans-muscular paraspinal approach. The level of the natural cleavage plane between the multifidus and the longissimus part of the sacrospinalis muscle was noted and measurements were done between this level and the midline at the level of the spinous process of L4. A natural cleavage plane between the multifidus and the longissimus part of the sacrospinalis muscle was present in all cases. There was a fibrous separation between the two muscular parts in 55 out of 60 cases. The mean distance between the level of the cleavage plane and the midline was 4 cm (2.4-5.5 cm). In all cases, small arteries and veins were present, precisely at the level of the cleavage plane. We found it possible to easily localize the anatomical cleavage plane between the multifidus part and the longissimus part of the sacrospinalis muscle. First the superficial muscular fascia is opened near the midline, exposing the posterior aspect of the sacrospinalis muscle. Then, the location of the muscular cleft can be found by identifying the perforating vessels leaving the anatomical inter-muscular space.

Pre-operative planning when using the Wiltse approach to the lumbar spine

“…from the midline for the natural cleavage plane. 3,4 When skin incisions are made a set distance from the mid-line, access to the facet joint and pars is compromised due to mismatch between the position of the skin incision and that of the cleavage plane.…”

A comparison of the Wiltse versus midline approaches in degenerative conditions of the lumbar spine

“…7,36 One of the potential limitations of the Wiltse approach is that central decompression is technically more difficult to achieve, but this is overcome as one gains familiarity with the approach. 30,31 There are numerous studies that have evaluated the effect of dissection time and extent of surgical retraction during midline spine surgery on local muscle function, vascularity, and viability. Studies in animals and humans have consistently shown that prolonged paraspinal muscle retraction predisposes patients to increased pain and a higher degree of tissue necrosis and puts them at a potentially greater risk of infection.…”

The Michel Benoist and Robert Mulholland yearly European Spine Journal review

“…Having used for some 30 years the approach (Wiltse) it might be thought that this paper by Vialle et al [36] had little to teach me. However, I had often been struck by the variability in terms of bleeding and ease of dissection of the approach as I did it.…”