Imaging features and postoperative outcomes in patients with degenerative lumbar scoliosis and pelvic obliquity

English Keywords:Degenerative lumbar scoliosis  Pelvic obliquity  Imaging features  Orthopedics surgery  Orthopedics strategy

English Abstract:

  【Abstract】 Objectives: To summarize the imaging characteristics of pelvic obliquity in patients with degenerative lumbar scoliosis(DLS), and to analyze the related imaging parameters and the outcome of pelvic obliquity after spinal correction surgery. Methods: The clinical data of 181 patients with DLS who underwent posterior scoliosis correction surgery in our hospital from January 2005 to December 2019 were retrospectively analyzed. There were 20 patients with pelvic obliquity before operation, aged 46-75 years(62.10±7.56 years). The follow-up time was 12-96 months(47.21±19.13 months). The C7 plumb line(C7PL) deviation direction of 15 patients was consistent with the higher side of the pelvic iliac crest, which was defined as type Ⅰ; The C7PL deviation direction of 5 patients was consistent with the lower side of the pelvic iliac crest, which was defined as type Ⅱ. The Cobb angle, coronal vertical axis(CVA), clavicle angle(CA), apical vertebral translation(AVT), sacral obliquity angle(SOA), and pelvic obliquity angle(POA), and clinical parameters such as apical vertebra position, fusion segment, the distal fixed vertebral position, and osteotomy method were collected before operation, after operation, and at the last follow-up and were compared within and between groups. Results: In type Ⅰ group, the Cobb angle, AVT, and POA after operation and at the last follow-up were significantly smaller than those before operation(P<0.05), and there was no significant difference in CVA, CA, and SOA compared with preoperative data(P>0.05). In type Ⅱ group, the postoperative AVT, Cobb angle, and POA were significantly smaller than those before operation(P<0.05), and there was no significant difference in CVA, CA, and SOA compared with preoperative data(P>0.05). At final follow-up, the SOA and AVT were significantly smaller than those before operation(P<0.05), and there was no significant difference in Cobb angle, CVA, CA, and POA compared with preoperative data(P>0.05). The preoperative SOA and AVT, postoperative Cobb angle, AVT and SOA at the last follow-up in type Ⅱ group were significantly higher than those in type Ⅰ group(P<0.05), and there was no significant difference in other radiological parameters between the two groups(P>0.05). In addition, there was no significant difference in clinical indicators such as the distal fixed vertebral position, apical vertebra position, fusion segment, and osteotomy method between the two groups(P>0.05). Persistent pelvic obliquity after operation occurred in 5 cases, and pelvic obliquity improved in 15 cases, with an improvement rate of 75%. The above mentioned imaging parameters of patients with persistent pelvic obliquity after operation and at the last follow-up were not significantly different from those before operation(P>0.05). The Cobb angle, AVT, and POA after operation and at final follow-up of patients with improved pelvic obliquity were significantly lower than those before operation(P<0.05). Conclusions: DLS and pelvic obliquity patients of type Ⅱ have more severe preoperative sacral and spinal deformities than those of type Ⅰ. For type Ⅰ patients, correction of Cobb angle and AVT is helpful for the improvement of pelvic obliquity after surgery.