Relationship between the endurance of preoperative spinal extensor muscles and clinical outcomes after correction of sagittal imbalance with long segment fusion in adult degenerative scoliosis

English Keywords:Degenerative scoliosis  Muscle endurance  Sagittal balance  Spine surgery

English Abstract:

  【Abstract】 Objectives: To investigate the influence of endurance of spinal extensor muscles on clinical outcomes after long segment fusion in adult degenerative scoliosis(ADS). Methods: Thirty-two patients with ADS who underwent long segment fusion surgery from January 2014 to October 2015 were reviewed. After spinal extensor muscle evaluation(swallow fly), patients were divided into two groups: 12 patients(55-73 years old, mean age of 65.2±4.7 years old) could complete the test(group A), and the other 20 patients(55-75 years old, mean age of 64.8±4.9 years old) failed(group B). The mean follow-up time was 1.5±0.5 years(1.3-2 years). The preoperative and postoperative radiographic parameters and clinical outcomes were recorded, including sagittal vertical axis(SVA), lumbar lordosis(LL), thoracic kyphosis(TK), thoracic lumbar kyphosis(TLK), pelvic tilt(PT), pelvic incidence(PI), sacral slope(SS), proximal junctional angle(PJA), and visual analogue scale(VAS), Japanese Orthopaedic Association(JOA), Oswestry disability index(ODI). Results: There was no significant difference in age, time of surgery, blood loss, or the average hospitalization(P>0.05) between the two groups. The preoperative LL, TLK, TK, SVA, PT, PI, SS, ODI VAS, JOA, in group A were 29.6°±3.2°, 33.5°±4.6°, 54.6°±5.1°, 9.9°±2.1cm, 28°±2.4°, 54.8°±4.1°, 26°±3.7°, (75.4±3.5)%, 7.3±0.9, 8.7±0.5; those were 29.7°±3.6°, 35.3°±3.8°, 55.2°±3.7, 9.4±1.6cm, 28°±1.6°, 52.2°±1.7°, 23.4°±2.9°, (76.4±2.2)%, 7.2±0.7, 8.5±0.5 in group B. And the immediately postoperative LL, TLK, TK,SVA, PJA, PT, SS, ODI, VAS, JOA in group A were 41.5°±4.1°, 8.8°±3.6°, 25.8°±2.1°, 3.6°±1.0°, 3.6°±1.1°, 14.8°±1.2°, 40.8°±2.5°, (21.9 ±2.3)%, 2.4±0.7, 23.2±1.4; and those were 40.6°±2.2°, 10.1°±3.2°, 27.3°±1.9°, 3.5±1.0cm, 3.8°±1.1°, 16.9°±2.3°, 35.3°±2.7°, (20.3±2.2)%, 2.9±0.6, 23.0±1.3 in group B. At the final follow-up, parameters and scores in group A were 43.6°±4.3°, 10.8°±3.6°, 28.7°±1.8°, 4.8±1.0cm, 4.4°±1.5°, 15.8°±1.2°, 41.8°±2.7°, (14.5±5.1)%, 2.0±1.6, 24.7±0.7, and 43.2°±2.0°, 18.6°±3.2°, 38.4°±3.2°, 8.7±1.6cm, 8.3°±2.6°, 23.6°±2.6°, 9.1°±3.3°, (28.7±3.2)%, 4.6±1.7, 24.0±1.0 in group B. There were no significant differences in the radiographic parameters and clinical outcomes(P>0.05) between the two groups before operation and immediately after operation. At the last follow-up, there was no significant difference in LL, but there were significant differences in TK, TLK, PT, SS, SVA, PJA between the two groups. Meanwhile, proximal junctional kyphosis occured in 3 patients. There were significant differences in DOI and VAS scores between the two groups at final follow-up, scores in group A were better than those in group B(P＜0.05). Conclusions: Endurance of spinal extensor muscles is important to protect the sagittal balance after long segment fusion surgery in adult degenerative scoliosis. Good preoperative endurance of spinal extensor muscles may decrease the rate of proximal junctional kyphosis.