Does corrective spine surgery improve the standing balance in patients with adult spinal deformity?

• Published in: The spine journal Vol. 18; no. 1; pp. 36 - 43
• Main Authors: Yagi, Mitsuru, Ohne, Hideaki, Kaneko, Shinjiro, Machida, Masafumi, Yato, Yoshiyuki, Asazuma, Takashi
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.01.2018
• Subjects: Absorptiometry, Photon; Adult spinal deformity; Aged; Alignment; Balance; Compensation; Female; Humans; Lordosis - diagnostic imaging; Lordosis - surgery; Male; Middle Aged; Muscle Strength; Neurosurgical Procedures - adverse effects; Orthopedics; Postoperative Complications - diagnostic imaging; Postoperative Complications - epidemiology; Postural Balance; Posture; Scoliosis - diagnostic imaging; Scoliosis - surgery; Spinopelvic alignment; Surgery; Spinopelvic alignment; Alignment; Adult spinal deformity; Balance; Compensation; Surgery
• ISSN: 1529-9430; 1878-1632; 1878-1632
• DOI: 10.1016/j.spinee.2017.05.023

The effect of corrective spine surgery on standing stability in adult spinal deformity (ASD) has not been fully documented. To compare pre- and postoperative standing balance and posture in patients with ASD. This study is a prospective case series. Standing balance before and after corrective spine surgery was compared in 35 consecutive female patients with ASD (65.6±6.9 years, body mass index 22.3±2.7 kg/m2, Cobb angle 50.2±19.2°, C7 plumb line 9.3±5.6 cm, and pelvic incidence-lumbar lordosis mismatch 40.8±23.3°). The Scoliosis Research Society Patient Questionnaire, the Oswestry Disability Index, and force-plate analysis were used to evaluate the patient outcomes. We reviewed patient charts and X-rays and compared standing balance before and after corrective spine surgery. All subjects were assessed by force-plate analysis using optical markers while standing naturally on a custom-built force platform. The spinal tilt, pelvic obliquity, pelvic tilt, and joint angle were calculated. The lower leg lean volume was obtained by whole-body dual X-ray absorptiometry to assess muscle strength. ASD patients showed significant differences between the left and right sides in ground reaction force (dGRFs), hip (dHip), and knee angle (dKnee) while standing (dGRF 15.1±8.7%, dHip 7.1±6.6°, dKnee 5.9±5.5°). The recorded center-of-gravity (CoG) area was not improved after surgery, whereas the dGRF, dHip, and dKnee all decreased. The spinal tilt, pelvic obliquity, and pelvic tilt were all significantly improved after surgery. We found significant correlations between the radiographic trunk shift and the postoperative coronal CoG distance and recorded CoG area, and between the sagittal CoG distance and the age and the lean volume of the lower extremities (trunk shift R=0.33, 0.45; age R=0.32; lean volume R=0.31). Corrective spinal surgery improved the spinal alignment and joint angles in patients with ASD but did not improve the standing stability. A correlation found between the sagittal CoG distance and the lean volume of the lower extremities indicated the importance of the leg muscles for stability when standing, whereas a correlation found between the coronal CoG distance and trunk shift reflected the attenuated postural response in the ASD patients.