The compensatory mechanisms for global sagittal balance in degenerative spinal kyphosis patients: a radiological analysis of muscle-skeletal associations

Abstract

Background The position of the head relative to the spine can be used to evaluate the true global balance in patients with degenerative spinal kyphosis (DSK). However, it is still not clear how the position of the head is related to the spinal-pelvic parameters and lumbar muscles, which are most commonly considered. Methods Sixty-seven patients with DSK admitted in the hospital from January 2017 to January 2019 were retrospectively analyzed. All patients had whole spine X-ray and lumbar MRI. The head position parameters include: the angles of both lines joining the center of acoustic meati (CAM) to the center of the bi-coxofemoral axis (BA) (CAM-BA) and the most superior point of dentiform apophyse of C2 odontoid (OD) to BA (OD-BA) with the vertical line; the distance between the vertical line passing CAM and the posterior upper edge of the S1 (CAM-SVA). The spinal parameters include: C7 sagittal vertical axis (C7-SVA), thoracic kyphosis (TK), thoracolumbar kyphosis (TLK), and lumbar lordosis (LL). The pelvic parameters include: pelvic incidence (PI), pelvic tilt (PT) and sacral slope (SS). The relative cross-sectional area (RCSA) of bilateral multifidus, erector spinae and psoas muscle at L3/4 and L4/5 segments were measured. The correlations between head position parameters and the spinal-pelvic parameters and RCSA of lumbar muscles were analyzed, respectively. Results Significant positive correlations were found between each two of CAM-SVA, C7-SVA, CAM-BA and OD-BA (p < 0.001). SS was found to be significantly positively correlated with CAM-BA (r = 0.377, p = 0.034) and OD-BA (r = 0.402, p = 0.023). CAM-BA was found to be significantly negatively correlated with TK (r = − 0.367, p = 0.039). Significant positive correlations were found between RCSA of multifidus at L3/4 level and CAM-SVA (r = 0.413, p = 0.021), CAM-BA (r = 0.412, p = 0.019) and OD-BA (r = 0.366, p = 0.04). Conclusions Our study showed that the head position relative to the spine were significantly correlated to some spinal-pelvic parameters, and the lower lumbar multifidus muscle. The compensatory mechanisms of the global sagittal balance status should also involve the head position area.

The Impact of Internal Compensatory Mechanisms on Musculoskeletal Pain in Elite Polish Sitting Volleyball Players – A Preliminary Study

“…Moreover, the aforementioned factors may have contributed to deviations of the anteroposterior spinal curvatures were found in the majority of participants (especially thoracic hyperkyphosis and lumbar hypolordosis). The results of our study correspond with the findings of Xia et al (2021) who reported a relationship between upper and lower sagittal compensatory mechanisms, in which the head position relative to the spine was significantly correlated with spinal-pelvic variables and lower lumbar muscles. Considering the factors related to the prevalence and location of musculoskeletal pain in sitting volleyball players, our results indicate that excessive fat mass (assessed by the corrected BMI, i.e., Brown-Fisher rate) impacted wrist pain in athletes with lower limb deficiency.…”

“…Moreover, the aforementioned factors may have contributed to deviations of the anteroposterior spinal curvatures were found in the majority of participants (especially thoracic hyperkyphosis and lumbar hypolordosis). The results of our study correspond with the findings of Xia et al (2021) who reported a relationship between upper and lower sagittal compensatory mechanisms, in which the head position relative to the spine was significantly correlated with spinal-pelvic variables and lower lumbar muscles.…”

“…External compensatory mechanisms are known as body’s adaptation to sport specific movements ( Gaweł and Zwierzchowska, 2021 ), whereas internal compensatory mechanisms are defined as self-activating changes in the musculoskeletal system which are interdependent mostly with biomechanical factors, muscular strength and body composition ( Brandt and Huang, 2019 ; Elsayed et al, 2018 ; Gaweł and Zwierzchowska, 2021 ; Hendershot and Nussbaum, 2013 ). The aforementioned mechanisms are essential to keep the sagittal balance of the spine, however, simultaneously they disturb intrinsic body biom-echanics ( Xia et al, 2021 ).…”

Postoperative Gravity Line-Hip Axis Offset as a Substantial Risk Factor for Mechanical Failure After Adult Spinal Deformity Correction Surgery

“…28 However, the C7 plumb line was found to be poorly correlated with GL, 11 and it has been well-studied that head balance, the cervical spinal curve, and lower limbs also contribute to the global balance of the spine although these factors are not incorporated in the C7-SVA concept. 9,20,21 The center of gravity, or GL, is an important concept, for which only a few studies have been conducted on normal values. 12,14 Humans maintain their posture with the available musculature and joints while not harming the purpose of horizontal gaze.…”

“…However, numerous radiographic parameters investigated to date cannot consistently predict MF. 9,[19][20][21] Even patients with ASD with well-corrected sagittal alignment parameters in SRS-Schwab or global alignment and proportion criteria sometimes develop MF, which reflects the limitation of parameters mostly involving the fixed segments only. 22 The need has arisen for a perspective to better understand spinal balance that also incorporates unfused spinal segments with a dynamic compensatory capacity and the chance of further degeneration.…”