Walking balance and compensatory gait mechanisms in surgically treated patients with adult spinal deformity

Background Context Gait patterns and their relationship to demographic and radiographic data in patients with adult spinal deformity (ASD) have not been fully documented. Purpose This study aimed to assess gait pattern in patients with ASD and the effect of corrective spinal surgery on gait. Design/Setting This is a prospective case series. Patient Sample The gait patterns of 33 consecutive women with ASD (age 67.1 years; body mass index [BMI] 22.5±2.5 kg/m², Cobb angle 46.8±18.2°, coronal vertical axis [CVA] 1.5±3.7 cm, C7 sagittal vertical axis [SVA] 9.1±6.4 cm, pelvic incidence minus lumbar lordosis [PI−LL] 38.2±22.1°, and lean volume of the lower leg, 5.5±0.6 kg) before and after corrective surgery were compared with those of 33 age- and gender-matched healthy volunteers. Outcome Measures Scoliosis Research Society Patient Questionnaire (SRS22r), Oswestry Disability Index (ODI), and forceplate analysis. Methods All subjects underwent gait analysis on a custom-built forceplate using optical markers placed on all joints and spinal processes. Dual X-ray absorptiometry scores were used to calculate the lean composition of the lower legs. Subjects with ASD were followed for at least 2 years post operation. Results Preop mean values showed that patients with ASD had a significantly worse gait velocity (54±10 m/min vs. 70.7±12.9 m/min, p<.01) and stride (97.8±13.4 cm vs. 115.3±15.1 cm, p<.01), but no difference was observed in the stance-to-swing ratio. The right and left ground reaction force vectors were also discordant in the ASD group (vertical direction; r=0.84 vs. r=.97, p=.01). The hip range of motion (ROM) was also significantly decreased in ASD. Correlation coefficient showed moderate correlations between the preoperative gait velocity and the gravity line (GL), PI, ROM of the lower extremity joints, and lean volume, and between the stride and the lean volume, GL, and PI−LL. Gait pattern, stride, and velocity all improved significantly in the patients with ASD after surgery, but were still not as good as in healthy volunteers. The SRS22r satisfaction domain correlated moderately with postoperative gait velocity (r=0.34). Conclusions The patients with ASD had an asymmetric gait pattern and impaired gait ability compared with healthy volunteers. Gait ability correlated significantly with the GL, spinopelvic alignment, lower extremity joint ROM, and lean volume. The surgical correction of spinopelvic alignment and exercises to build muscle strength may improve the gait pattern and ability in patients with ASD.