Neutral hip position for the oblique lumbar interbody fusion (OLIF) approach increases the retroperitoneal oblique corridor

Antepsoas Approaches to the Lumbar Spine

Lumbar interbody fusion (LIF) is a well-established approach in treating spinal deformity and degenerative conditions of the spine. Since its inception in the 20th century, LIF has continued to evolve, allowing for minimally invasive approaches, high fusion rates, and improving disability scores with favorable complication rates. The anterior to the psoas (ATP) approach utilizes a retroperitoneal pathway medial to the psoas muscle to access the L1-S1intervertebral disc spaces. In contrast to the transpsoas arppoach, its primary advantage is avoiding transgressing the psoas muscle and the contained lumbar plexus, which potentially decreases the risk of injury to the lumbar plexus. Avoiding transgression of the psoas may minimize the risk of transient or permanent neurological deficits secondary to lumbar plexus injury. Indications for ATP approaches may expand as it is shown to be a safe and effective method of achieving spinal arthrodesis.

Imaging study of the effect of postural changes on the retroperitoneal oblique corridor in degenerative lumbar scoliosis

PURPOSE

To investigate the effect of postural changes on access for the OLIF of L2 to L5 in patients with degenerative lumbar scoliosis.

METHODS

Twenty-one individuals with degenerative lumbar scoliosis were chosen at random, 11 with left-sided convexity and 10 with left-sided concavity. Axial T2-weighted images were used to measure the following variables: (1) the distance between the left psoas major muscle and the abdominal aorta; (2) the angle of the surgical access; (3) the distance between the psoas major muscle attachment point and the vertebral body's transverse axis; (4) the region of the psoas major muscle above the vertebrae; and (5) the width-to-thickness ratio. A statistical analysis of the measured parameters was done.

RESULTS

The L2-5 segment in the supine position had a significantly longer window distance in the left convex and left concave groups than in the right lateral recumbent posture (P < 0.05). In all segments, the left concave group outperformed the left convex group, which was substantially higher in the right lateral recumbent posture than in the supine position (P < 0.05). After the position change, the spanning area was significantly higher compared to the same segment in the supine position. The psoas major muscle's morphology was stretched.

CONCLUSIONS

The right lateral recumbent position limits access to OLIF for degenerative lumbar scoliosis, and the "safety window" for OLIF operation in the parietal region is smaller in the left convex group compared to the left concave group, posing a higher risk of intraoperative vascular and neurological injury.

Location of the Femoral Nerve in the Lateral Decubitus Versus Prone Position

STUDY DESIGN

Cadaveric study.

OBJECTIVE

To compare the position of the femoral nerve within the lumbar plexus at the L4-L5 disc space in the lateral decubitus vs prone position.

METHODS

Seven lumbar plexus specimens were dissected and the femoral nerve within the psoas muscle was identified and marked with radiopaque paint. Lateral fluoroscopic images of the cadaveric specimens in the lateral decubitus vs prone position were obtained. The location of the radiopaque femoral nerve at the L4-L5 disc space was normalized as a percentage of the L5 vertebral body (0% indicates posterior location and 100% indicates anterior location at the L4-L5 disc space). The location of the femoral nerve at L4-L5 in the lateral decubitus vs prone position was compared using a paired t test.

RESULTS

In the lateral decubitus position, the femoral nerve was located 28% anteriorly from the posterior edge of the L4-L5 disc space, and in the prone position, the femoral nerve was relatively more posterior, located 18% from the posterior edge of the L4-L5 disc space (P = .037).

CONCLUSIONS

The femoral nerve was on average more posteriorly located at the L4-L5 disc space in the prone position compared to lateral decubitus. This more posterior location allows for a larger safe zone at the L4-L5 disc space, which may decrease the incidence of neurologic complications associated with Lateral lumbar interbody fusion in the prone vs lateral decubitus position; however, further studies are needed to evaluate this possible clinical correlation.

Indirect Lumbar Decompression Combined With or Without Additional Direct Posterior Decompression: A Systematic Review

STUDY DESIGN

Systematic review.

OBJECTIVE

Indirect decompression via lateral lumbar interbody fusion (LLIF) can ameliorate central and foraminal lumbar stenosis. In severe central stenosis, additional posterior direct decompression is utilized. The aim of this review is to synthesize existing literature on these 2 techniques and identify significant differences in outcomes between isolated indirect decompression via LLIF and combined indirect decompression supplemented with direct posterior decompression.

METHODS

A database search algorithm was utilized to query MEDLINE, COCHRANE, and EMBASE to identify literature reporting adult decompression study groups that involved an oblique or lateral fusion approach through September 2020. Improvement in outcomes measures and complication rates were pooled and tested for significance.

RESULTS

A total of 110 publications were assessed with 15 studies meeting inclusion criteria, including 557 patients and 1008 levels. Mean age was 63.1 years with BMI of 27.5 kg/m². For the combined indirect and direct decompression cohort, lumbar lordosis (LL) increased 133.9%, from 22.8^o to 48.7^o, while the indirect decompression cohort LL increased 8.9%, from 41.9^o to 45.5^o. Difference in LL improvement between cohorts was insignificant (P > .05). Oswestry Disability Index (ODI) decreased from 36.5 to 19.4 in the combined indirect and direct decompression cohort, and from 44.4 to 23.1 in the indirect decompression cohort. ODI reduction was insignificant (P = .053).

CONCLUSIONS

Prior studies of both indirect decompression as well as combined indirect and direct decompression of lumbar spine stenosis are limited by small samples, heterogeneous populations, and lack of direct comparisons. Both procedures result in improved function and pain postoperatively with direct decompression restoring more lordosis in patients with worse preoperative alignment.

Pearls and Pitfalls of Oblique Lateral Interbody Fusion: A Comprehensive Narrative Review

Lumbar degenerative disease is a common problem in an aging society. Oblique lateral interbody fusion (OLIF) is a minimally invasive surgical (MIS) technique that utilizes a retroperitoneal antepsoas corridor to treat lumbar degenerative disease. OLIF has theoretical advantages over other lumbar fusion techniques, such as a lower risk of lumbar plexus injury than direct lateral interbody fusion (DLIF). Previous studies have reported favorable clinical and radiological outcomes of OLIF in various lumbar degenerative diseases. The use of OLIF is increasing, and evidence on OLIF is growing in the literature. The indications for OLIF are also expanding with the help of recent technical developments, including stereotactic navigation systems and robotics. In this review, we present current evidence on OLIF for the treatment of lumbar degenerative disease, focusing on the expansion of surgical indications and recent advancements in the OLIF procedure.