Retroperitoneal oblique corridor to the L2–S1 intervertebral discs in the lateral position: an anatomic study

Abstract

<jats:sec> <jats:title>Object</jats:title> <jats:p>Access to the intervertebral discs from L2–S1 in one surgical position can be challenging. The transpsoas minimally invasive surgical (MIS) approach is preferred by many surgeons, but this approach poses potential risk to neural structures of the lumbar plexus as they course through the psoas. The lumbar plexus and iliac crest often restrict the L4–5 disc access, and the L5–S1 level has not been a viable option from a direct lateral approach. The purpose of the present study was to investigate an MIS oblique corridor to the L2–S1 intervertebral disc space in cadaveric specimens while keeping the specimens in a lateral decubitus position with minimal disruption of the psoas and lumbar plexus.</jats:p></jats:sec> <jats:sec> <jats:title>Methods</jats:title> <jats:p>Twenty fresh-frozen full-torso cadaveric specimens were dissected, and an oblique anatomical corridor to access the L2–S1 discs was examined. Measurements were taken in a static state and with mild retraction of the psoas. The access corridor was defined at L2–5 as the left lateral border of the aorta (or iliac artery) and the anterior medial border of the psoas. The L5–S1 corridor of access was defined transversely from the midsagittal line of the inferior endplate of L-5 to the medial border of the left common iliac vessel and vertically to the first vascular structure that crosses midline.</jats:p></jats:sec> <jats:sec> <jats:title>Results</jats:title> <jats:p>The mean access corridor diameters in the static state and with mild psoas retraction, respectively, were as follows: at L2–3, 18.60 mm and 25.50 mm; at L3–4, 19.25 mm and 27.05 mm; and at L4–5, 15.00 mm and 24.45 mm. The L5–S1 corridor mean values were 14.75 mm transversely, from midline to the left common iliac vessel and 23.85 mm from the inferior endplate of L-5 cephalad to the first midline vessel.</jats:p></jats:sec> <jats:sec> <jats:title>Conclusions</jats:title> <jats:p>The oblique corridor allows access to the L2–S1 discs while keeping the patient in a lateral decubitus position without a break in the table. Minimal psoas retraction without significant tendon disruption allowed for a generous corridor to the disc space. The L5–S1 disc space can be accessed from an oblique angle consistently with gentle retraction of the iliac vessels. This study supports the potential of an MIS oblique retroperitoneal approach to the L2–S1 discs.</jats:p></jats:sec>

The Oblique Anterolateral Approach to the Lumbar Spine Provides Access to the Lumbar Spine With Few Early Complications

“…However, numerous studies have shown neurologic injury resulting from this transpsoas approach, which is in close anatomic proximity to the lumbar nerve plexus [2,16,18,25,26]. The oblique anterolateral retroperitoneal approach to the lumbar spine passes anterior to the psoas muscle and lateral to the abdominal vessels [11]. We found that the access through this anatomically predefined pathway was associated with a low risk of vascular and neurologic complications in a large cohort at a single center.…”

“…Davis et al [11], in a cadaveric study, described the retroperitoneal oblique corridor to the L2 to S1 intervertebral discs. They concluded that use of this oblique corridor, anterior to the psoas muscle, may avoid many of the anatomic structure-associated complications with the anterior or transpsoas approaches.…”

Evaluation of the location of intervertebral cages during oblique lateral interbody fusion surgery to achieve sagittal correction

“…This finding indicates that the more anterior the cage position, the more lordosis will be achieved. The amount of lordosis achieved can also depend on the approach to the spine, e.g., an oblique anteroposterior trajectory via the vacant oblique corridor in front of the psoas muscle 20) in OLIF or a direct lateral to lateral-anterior trajectory in XLIF 21) . These differences can also lead to an anterior longitudinal ligament (ALL) tear or injury, as XLIF can cause this complication when the cage is placed anteriorly because of its trajectory.…”

Morphometric anatomy of the lumbar sympathetic trunk with respect to the anterolateral approach to lumbar interbody fusion: a cadaver study

“…Cadaveric investigations by Davis et al (28) and Molinares et al (29) demonstrate an adequately sized, left-sided oblique corridor at L2-L5, which could be widened via lateral decubitus positioning and the use of approach retractor systems. The prior study (28) reported left oblique corridor sizes for L2/L3, L3/L4, L4/L5 whilst the latter (29) reported measurements of these levels in addition to L1/L2 and L2/L3. Both studies were consistent in demonstrating that the larger corridors were available in the upper lumbar levels, and has been attributed to the conical morphology of the psoas muscle.…”