The Effect of Preoperative Sagittal Malalignment on Clinical Outcomes in Short-Segment Lumbar Interbody Fusion

Study Designretrospective case-control study.ObjectivesThe objective is to investigate how preoperative sagittal malalignment affects clinical outcomes in short-segment lumbar interbody fusion.MethodsA total of 684 patients who underwent short-segment lumbar interbody fusion were reviewed with a minimum follow-up of 2 years. According to the SRS-Schwab Adult Spinal Deformity Classification, preoperative sagittal malalignment was defined as a sagittal vertical axis (SVA) ≥ 95 mm or pelvic tilt (PT) ≥ 30 degrees or Pelvic incidence (PI) - Lumbar lordosis (LL) ≥ 20 degrees in this study. Patients were divided into a well-alignment group and a malalignment group. Spinopelvic parameters such as thoracic kyphosis (TK), LL, lower LL (LLL), sacral slope (SS), PT, PI, SVA, T1 pelvic angle (TPA), and segmental lordosis (SL), as well as Visual Analog Scale (VAS) of low back pain and leg pain, Oswestry Disability Index (ODI), and Roland-Morris Disability Questionnaire (RDQ) were measured preoperatively and at the final follow-up.ResultsThe well-alignment group included 443 patients, and the malalignment group included 241 patients. In the malalignment group, PT, PI, SVA, and TPA were higher, whereas TK, LL, LLL, and SL were lower than in the well-alignment group. There were no significant differences between the groups regarding ΔVAS of low back pain, ΔVAS of leg pain, ΔODI, and ΔRDQ. The satisfaction rate was lower in the malalignment group.ConclusionThis study demonstrated that preoperative sagittal malalignment and spinopelvic parameters were not associated with clinical outcomes except for the satisfaction rate in short-segment lumbar interbody fusion.