Outcomes of Surgical Treatment of High-Grade Spondylolisthesis (Monocenter Cohort and Literature Review)

Purpose - to evaluate outcomes of surgical treatment for high-grade spondylolisthesis using bone-disc-bone osteotomy, reduction and fixation through the dorsal approach. Materials and Methods. The authors retrospectively examined a monocenter five-year cohort (IV level of evidence). The study included 10 patients aging from 7 to 22 years (Me - 12 years, M +/- m - 13.1 +/- 4.1 years) who underwent surgery due to high-grade spondylolysis antelisthesis in the period from 2012 to 2017. Displacement was located in L5-S1 segments and corresponded to types 4-6 by AOSpine SDSG classification in all patients. Catamnesis was followed for the period from 1 to 5 years. Surgical procedures included bone-disc-bone osteotomy, L5 reduction and dorsal instrumental multi-bearing (from 2 to 5 spinal motion segments) using reduction transpedicular screws. The following parameters were evaluated: pain syndrome prior and after surgery, sagittal balance, spondylolisthesis mobility on the functional X-rays or CYs, severity grade of anterior spondylolysis, criteria of spontaneous muscular activity and MEPs as well as structure of postoperative complications. Results. L5 displacement prior to surgery was 92.6 +/- 25.2%, after surgery - 25.4 +/- 16.6% (Z = -2.805, p = 0.005). Patients with sagittal imbalance demonstrated normalization after the surgery allowing to re-classify pathology as "balanced spondylolisthesis": PI from 67.9 +/- 8.6 to 67.5 +/- 8.7 (Z = 0,000, p = 1,000), PT from 26.8 +/- 13.3 to 20.1 +/- 7.1 (Z = -2,090, p = 0.037), SS from 41.3 +/- 8.7 to 47.3 +/- 9.7 (Z = -1.886, p = 0.059), SA from 34.9 +/- 36.3 degrees to 8.6 +/- 7.1 degrees (Z = -2.803, p = 0.005). 3 cases of transient L5 radiculopathy with full regress after conservative 6 months' treatment were reported in the early follow up period (on day 3 after procedure). Pain syndrome dynamics on VAS scale prior to and after the surgery were as follows: spine 8.1 +/- 1.0 and 0.5 +/- 0.5 (Z= -2.814, p = 0.005), lower limbs 6.8 +/- 1.5 and 0.4 +/- 0.7 (Z = -2.812, p = 0.005), respectively. Life quality indices by SRS-24 score prior to and after the surgery were 62.6 +/- 7.9 and 90.7 +/- 12.4 (Z = -2.803, p = 0.005). Mobility of spondylolisthesis was observed in 9 patients. Spondylolisthesis severity by Bridwell classification in late period scored from 1 to 3 points. Conclusion. Use of AOSpine SDSG classification along with assessment of sagittal balance as well as severity of neurological deficit and pain syndrome allow to define the severity grade of spondylolisthesis, while normalization of parameters after the surgery speaks for positive treatment outcome. Extensive release during bone-disc-bone osteotomy at L5-S1 level along with altering tilt angle of the sacrum is the key factor for mobilization and radical correction of pelvic balance in high-grade spondylolisthesis. Outcomes of surgical treatment in the analyzed cohort demonstrate significant improvement in life quality (by SRS-24 score) and reduced pain syndrome (by VAS) in patients. At the same time precise compliance to the procedure protocol and intraoperative neuro-monitoring of MEPs allow to decrease risk of complications.