The correlation study between PI-LL value and its clinical outcome in adult degenerative scoliosis deformity correction

English Keywords:Spino-pelvic alignment  PI-LL  Sagittal balance

English Abstract:

  【Abstract】 Objectives: To investigate the relationship between the PI-LL value and its clinical outcomes after adult degenerative scoliosis surgery. Methods: 42 patients who received long-segment correction for degenerative scoliosis between January 2011 and December 2012 in our hospital were analyzed retrospectively. Follow-ups were more than 3 years. Pre-operatively and at final follow-up, patients undertook full-long standing X-ray of spine, meanwhile VAS and ODI scores were recorded. The scoliosis Cobb′s angle, pelvic incidence, sacral slope, pelvic tilt, lumbarlordosis, thoracic kyphosis, pelvic radius-T12, T1 pelvic angle and sagittal vertical axis were measured. The radiological parameters and clinical function scores pre- and post-operatively were compared, to analysis the correlation of these parameters with PI-LL value, and the impact on patients quality of life(ODI) of different PI-LL values. Results: The average age of patients was 68.8 years. Pre-operative scoliosis Cobb′s angle was 19.5°±5.4°, which improved to 6.1°±3.5° at final follow-up(P<0.01). The average lumbar lordosis increased from 20.7° to 34.3°, PI-LL was 9.0° at final follow-up and SVA decreased from 7.6cm to 5.7cm, the differences were significant(P<0.01). Sagittal balanced group included 10 patients, PI-LL was 1.0°±5.9° at final follow-up. Sagittal unbalanced group included 32 patients， PI-LL was 11.8°±9.0° at final follow-up. Pre-operative VAS and ODI scores between two groups were not significant, but improved obviously at final follow-up. There were no significant differences with VAS and ODI scores between two groups at final follow-up(P=0.074/0.053). Post-operative PI-LL had significant correlations with postoperative PR-T12, TPA, SVA, VAS and ODI score. ODI score between PI-LL≤10°group and 10°15° group(P=0.010/0.048). Conclusions: The sagittal alignment during surgical treatment for degenerative scoliosis should be carefully evaluated. Post-operative PI-LL<15° suggests matched pelvis and lumbar lordosis for senior patients, helps to maintain the spino-pelvic balance, and significantly improves the patients′ clinical outcome and quality of life.