Quantitative analysis of paraspinal muscle atrophy after oblique lateral interbody fusion alone vs. combined with percutaneous pedicle screw fixation in patients with spondylolisthesis.

BACKGROUND: There is no available literature for comparison on muscle atrophy between the "stand-alone" oblique lateral interbody fusion (OLIF) and regular OLIF (i.e., combined with percutaneous pedicle screws fixation (PPSF) in patients with spondylolisthesis). This study aimed to identify changes in back muscle atrophy between the two surgeries. METHODS: This was a retrospective cohort study of patients who underwent OLIF or OLIF+PPSF at Beijing Jishuitan Hospital and Shanghai ChangZheng Hospital between 07/2014 and 10/2017. Computed tomography (CT) was used to measure functional cross-sectional area (FCSA) and fat infiltration percentage (FIP) of the multifidus and erector spinae before and 24 months after surgery. RESULT: There were no differences in FCSA and FIP between OLIF (n = 32) and OLIF+PPSF (n = 41) groups before surgery. In the OLIF group, the multifidus and erector spinae FCSA and FIP did not change at 24 months (FCSA: multifidus: from 8.59 +/- 1.76 to 9.39 +/- 1.74 cm(2), P = 0.072; erector spinae: from 13.32 +/- 1.59 to 13.55 +/- 1.31 cm(2), P = 0.533) (FIP: multifidus: from 15.91 +/- 5.30% to 14.38 +/- 3.21%, P = 0.721; erector spinae: from 11.63 +/- 3.05% to 11.22 +/- 3.12%, P = 0.578). In the OLIF+PPSF group, the multifidus and erector spinae FCSA decreased (multifidus: from 7.72 +/- 2.69 to 5.67 +/- 1.71 cm(2), P < 0.001; erector spinae: from 12.60 +/- 2.04 to 10.15 +/- 1.82 cm(2), P < 0.001), while the FIP increased (multifidus: from 16.13 +/- 7.01% to 49.38 +/- 20.54%, P < 0.001; erector spinae: from 11.93 +/- 3.22% to 22.60 +/- 4.99%, P < 0.001). The differences of FCSA and FIP between the two groups at 24 months were significant (all P < 0.001). The patients in the standalone OLIF group had better VAS back pain, and JOA scores than the patients in the OLIF combined group (all P < 0.05) at 1 week and 3 months after surgery. There were two cases (4.9%) of adjacent segment degeneration in the OLIF combined group, while there was no case in the OLIF alone group. CONCLUSIONS: Standalone OLIF had better clinical outcomes at 1 week and 3 months than OLIF+PPSF in patients with spondylolisthesis. OLIF may not result in paraspinal muscle atrophy at 24 months after surgery.