Page 51 - WNS 2022 Program Book-Final version

Antepsoas versus Transpsoas Approach to Lateral Lumbar Interbody
Fusion
Mohamed Macki, MD MPH University of California, San Francisco

Introduction: The operative approach to lateral lumbar interbody fusion (LLIF)
includes anterior-to-the-psoas (antepsoas) and through-the-psoas
(transpsoas). While the surgical corridor to the lateral disc is based on surgeon
comfort level, few studies have elucidated the differences in outcomes.

Methods: All patients undergoing LLIF for degenerative/deformity lumbar dis-
ease were retrospectively collected. Any patient undergoing L5-S1 interbody
fusion or posterior osteotomy was excluded. All patients had preoperative and
postoperative standing scoliosis X-rays as well as a minimum of 1 year follow-
up. Complications were recorded within 6 weeks postoperatively.

Results: Transpsoas patients(n=40) underwent larger operations than an-
tepsoas patients(n=53), with a median of 2- vs 1-level interbody fusions, re-
spectively(p=0.035), and a median of 3- vs 2- level posterior fixation, respec-
tively(p=0.001). Although the coronal Cobb angle was significantly greater in
the antepsoas(9.2° vs 6.0°,p=0.018), the change (postoperative- preoperative)
in all spinopelvic parameters was equivalent between the two approaches.
Segmental lordosis did not differ between the two approaches at L1-L2, L2-L3,
L3-L4, or L4-L5. The disc height postoperative was statistically significantly
higher in the transpsoas (10.2 mm) versus antepsoas (8.8 mm) cages
(p=0.020). Mean change in disc height was statistically significantly greater in
the transpsoas group (4.3mm vs 0.1 mm, p;0.001)

Conclusion: Both lateral approaches appropriately improved spinopelvic pa-
rameters. However, the transpsoas group provided greater disc height restora-
tion.

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