The effect of lower level three-column osteotomies(L-3COs) on the reconstruction of coronal and sagittal balance in adult spinal deformity

English Keywords:Lower level three-column osteotomies  Adult spinal deformity  Kyphoscoliosis  Coronal imbalance  Sagittal imbalance

English Abstract:

  【Abstract】 Objectives: To investigate the effect of lower-level three-column osteotomies(L-3COs) on the restoration of coronal and sagittal balance in adult spinal deformity(ASD). Methods: The clinical data of ASD patients treated with L-3COs (L4, L5 level) in our hospital between January 2012 and May 2022 were retrospectively analyzed. A total of 34 patients were included in this study, including 7 males and 27 females, aged 51.4±16.2 years (range 18-72 years). According to the Qiu classification, 10 cases were classifies as type A, 13 cases as type B, and 11 cases as type C； 9 cases were of congenital spinal deformity, 3 cases were of idiopathic scoliosis, 20 cases were of degenerative scoliosis, and 2 cases were of neurogenic scoliosis; 7 patients underwent subsequent revision. All the patients underwent L-3COs+pelvic fixation and were followed up for ≥2 years. Imaging parameters assessing coronal and sagittal spine and trunk balance were measured at preoperation, immediate postoperatively, and at the final follow-up to evaluate the corrective outcomes. Coronal parameters included the Cobb angle, coronal balance distance(CBD), and L4 tilt angle. Sagittal parameters included sacral slope(SS), pelvic tilt(PT), pelvic incidence(PI), lumbar lordosis(LL), L4-S1 lordosis, thoracic kyphosis(TK), and sagittal vertical axis(SVA). The operative time, intraoperative blood loss, osteotomy level, and complications were documented, and clinical outcomes were appraised using the Scoliosis Research Society-22(SRS-22) questionnaire. Results: The operative time was 5.7±0.9h(4.6-7.0h), and the intraoperative blood loss was 1870±550mL(1320-3840mL). The osteotomy level was L4 in 25 cases and L5 in 9 cases. Except for PI, all the coronal and sagittal parameters significantly improved postoperatively compared to preoperative values(P<0.05). The CBD of the patients was 24.52±19.60mm preoperatively and was corrected to 11.94±10.74mm immediately postoperatively(P=0.032). The SVA was 98.25±48.40mm preoperatively and reconstructed to 31.26±36.06mm immediately postoperatively(P<0.001). The LL was 8.59°±11.76° preoperatively and was significantly corrected to 36.82°±10.73° immediately postoperatively(P<0.001). 8 patients suffered with postoperative mechanical complication, no revision for complications, and there were 2 cases of proximal junctional kyphosis(PJK), 5 instances of rod or screw breakage, 1 case of screw loosening or pullout, and 1 case of coronal imbalance(1 case presented with both PJK and coronal imbalance). The scores of all dimensions of SRS-22 questionaire(function, pain, self-image, mental health, total score) at final follow-up were significantly higher than those preoperatively(P<0.001). Conclusions: L-3COs demonstrate significant correction effects for ASD patients with severe coronal and sagittal imbalance and loss of LL, which successfully alleviates pain and enhances long-term quality of life, with a relatively low incidence of postoperative mechanical complications, making it an effective orthopaedic technique.