Tandem Spondylolisthesis and the Rising Psoas: The Danger of the Direct Lateral Trans-psoas Approach — The International Society for the Study of the Lumbar Spine
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  2. SESSION #3 - SPONDYLOLISTHESIS
  3. Tandem Spondylolisthesis and the Rising Psoas: The Danger of the Direct Lateral Trans-psoas Approach

Tandem Spondylolisthesis and the Rising Psoas: The Danger of the Direct Lateral Trans-psoas Approach (#12)

Anthony A Oyekan 1 , Dominic Ridolfi 1 , Brandon K Couch 1 , Aaron Zheng 1 , Asher Mirvish 1 , Jonathan F Dalton 1 , Audrey Chang 1 , Christopher M Gibbs 1 , Jeremy D Shaw 1 , William F Donaldson 1 , Joon Y Lee 1
  1. Department of Orthopaedic Surgery, Univeristy of Pittsburgh Medical Center, Pittsburgh, PA, United States

INTRODUCTION: The direct-lateral (trans-psoas) approach to the spine is a popular choice for interbody fusion procedures in the management of spondylolisthesis and degenerative disc disease. There are known risks of lumbar plexus and femoral nerve injury making preoperative planning essential. Previous investigators have described “the rising psoas sign” where the psoas muscle drifts anteriorly away from the vertebral column on advanced imaging axial views creating increased risk with the direct lateral approach. The purpose of the present study was to examine the association of sequential multilevel (tandem) spondylolisthesis and psoas position at the L4-L5 lumbar level.  

METHODS: Subjects with lumbar spine MRIs and/or full-length spine films were identified and stratified into 3 age and gender-matched cohorts: 1) No spondylolisthesis, 2) Single level lumbar spondylolisthesis, & 3) sequential multilevel (tandem) lumbar spondylolisthesis. Medical records were retrospectively reviewed. The position of the psoas muscle (centrally and apically) relative to a tangent line at the posterior aspect of the L4-5 disc was measured. Spinopelvic parameters were recorded in all patients with full-length spinal films. Chi-square analysis was used to determine differences in gender. Two-tailed unpaired t-tests were used to identify differences in continuous variable demographics and radiographic measurements. p < 0.05 was considered statistically significant.

RESULTS: Two hundred and one subjects (75 M, 126 F; age 63±13 years) were identified. No spondylolisthesis patients (n=52, 20 M, 32 F, age 61±19, BMI 30.80±7.03, aCCI 3±2), single-level spondylolisthesis patients (n=110, 41 M, 69 F, age 63±12, BMI 31.44±6.95, aCCI 3±2), and tandem spondylolisthesis patients (n=39, 14 M, 25 F, age 65±8, BMI 30.66±7.29, aCCI 3±2) had no differences in demographics (p >0.1). The center (C) psoas and apical (A) psoas position was more ventral in patients with tandem spondylolisthesis (n=39) (C: 28.9 mm ±10.1 mm & A: 50.9 mm) as compared to patients with single-level spondylolisthesis (n=110) (C: 24.3 mm ±7.3 mm; p = 0.012 & A: 46.7 mm; p = 0.041) and no spondylolisthesis (n=52) (C: 23.4 mm ±8.0 mm; p = 0.007 & A: 45.3 mm ±9.9mm; p = 0.019). Tandem spondylolisthesis was associated with increased pelvic tilt (27°±11°) vs. single-level spondylolisthesis (21°±11°; p = 0.002) and no spondylolisthesis (17°±12°​; p <0.001). Pelvic incidence was increased in subjects with tandem spondylolisthesis (65°±19°; p = 0.001) and single-level spondylolisthesis (61°±23°​; p = 0.026​) compared to patients with no spondylolisthesis (54°±25°​). Tandem spondylolisthesis was also associated with increased pelvic incidence-lumbar lordosis mismatch (18°±16°) vs. single-level spondylolisthesis (7°±13°; p<0.001) vs. no spondylolisthesis (11°±19°; p = 0.059). There were no significant differences for the tandem spondylosis group in lumbar lordosis angle, sacral slope, or sagittal vertical axis angle (p>0.1). Single level spondylolisthesis was associated with increased lumbar lordosis (52°±17° vs. 43°±20°; p = 0.003) compared to patients with no spondylolisthesis.

DISCUSSION: Tandem spondylolisthesis is associated with a more ventrally positioned psoas muscle which poses a danger in trans-psoas approaches to the lumbar spine. Careful pre-operative planning with attention to the psoas position for lateral interbody fusion candidates is recommended.

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  1. Kepler, C. K., Bogner, E. A., Herzog, R. J., & Huang, R. C. (2011). Anatomy of the psoas muscle and lumbar plexus with respect to the surgical approach for lateral transpsoas interbody fusion. European spine journal : official publication of the European Spine Society, the European Spinal Deformity Society, and the European Section of the Cervical Spine Research Society, 20(4), 550–556. https://doi.org/10.1007/s00586-010-1593-5
  2. Tanida, S., Fujibayashi, S., Otsuki, B., Masamoto, K., & Matsuda, S. (2017). Influence of spinopelvic alignment and morphology on deviation in the course of the psoas major muscle. Journal of orthopaedic science : official journal of the Japanese Orthopaedic Association, 22(6), 1001–1008. https://doi.org/10.1016/j.jos.2017.08.002
  3. Voyadzis, J. M., Felbaum, D., & Rhee, J. (2014). The rising psoas sign: an analysis of preoperative imaging characteristics of aborted minimally invasive lateral interbody fusions at L4-5. Journal of neurosurgery. Spine, 20(5), 531–537. https://doi.org/10.3171/2014.1.SPINE13153
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