Effect of the reconstructed sagittal balance on outcomes in the elderly with degenerative low-grade spondylolisthesis: single center four-year cohort study

Objective To explore the effect of surgical reconstruction of the local sagittal balance on the outcomes and quality of life in elderly with degenerative low-grade spondylolisthesis. Design: a retrospective non-randomized single center cohort study. Material and methods This article reviewed 110 elderly patients (91 (82.7 %) females and 19 (17.3 %) males) with degenerative spondylolisthesis who underwent surgical treatment at the Federal State Medical Center, Novosibirsk. The mean age was 66 years (range, 60 to 83 years). Radiography, spiral computed tomography, MRI of the lumbar spine were performed for all patients who were also asked to use the visual analog scale and the Oswestry disability index (ODI). Sagittal spino-pelvic radiographic parameters including PI, SS, PT, LL, SL (Segmental Lordosis), LL4-S1 (Lordosis L4-S1) were measured and related to age. Global lumbar lordosis measurements were made using the formula: LL = 0.54 × PI + 27.6°. Comorbidity assessment was produced with the body mass index (BMI) and the Charlson Comorbidity Index (CCI). Patients were subdivided into three groups according to the severity of the sagittal imbalance as described by Barrey: (1) balanced, (2) balanced with compensatory mechanisms and (3) imbalanced, and their outcomes evaluated. Results Increased body weight was observed in 97.3 % of patients. The mean BMI was 33.7. A comorbid condition was detected in all patients (n = 110). The mean CCI was 57.4 %. The mean PI was 57.4°. Most of patients (n = 95, 86.4 %) had significant segmental imbalance due to the loss of segmental lordosis at the lower lumbar motion segments. Pelvic retroversion was identified as the compensatory mechanism in the pelvis area in 95 % of patients with measurements of PT based on the available PI. A statistically significant increase in LL4-S1 was observed in the groups due to reduction of spondylolisthesis and restoration of the segmental lordosis. A statistically significant increase in LL was observed in the imbalanced group only. No statistically significant differences in ODI scores were observed in TLIF and ALIF/LLIF patients. Complications graded in the Clavien-Dindo classification were identified in 65 (59 %) cases with greater complication rate in TLIF patients (n = 59, 69 %), as compared to ALIF/LLIF (n = 6, 24 %). From them, 5 (0.5 %) were graded IIIB. Conclusion Differentiated use of surgical technologies and MIS is the method of choice for elderly patients with comorbidities. Patients with compensated sagittal balance can benefit from direct spinal canal decompression, reduction and stabilization of degenerative spondylolisthesis using the posterior approach. Treatment of patients with impaired spino-pelvic balance should be aimed at reduction and restoration of the segmental lordosis (SL) using lordotic cages to ensure good clinical and radiological results.