The relationship of global sagittal malalignment to fatty infiltration in the aging spine

Abstract

Purpose To investigate associations between muscle size, fat infiltration (FI), and global sagittal alignment in patients with adult spinal deformity (ASD). Methods Retrospective cohort study was conducted on a single-institution database of ASD patients with preoperative radiographs and CTs. Following multiplanar reconstructions of CTs, images in the plane of each vertebra were generated. The posterior vertebral musculature (PVM) was contoured on axial images at three vertebral levels (T2, T10, L3). FI was calculated by comparing Hounsfield units within muscles to the normative values of fat. Correlation analyses were conducted between demographics, alignment, and muscle characteristics. Results 107 patients underwent preoperative spine CT (58yo, 79%F, BMI 27 kg/m2). Muscle data were available for 49 pts at T2, 39 pts at T10, and 81 pts at L3. Mean FI was T2 = 33% ± 18, T10 = 28% ± 19, L3_Erector = 39% ± 19, and L3_Psoas = 19% ± 9. FI correlated across levels (T2 vs. T10 r = 0.698; T10 vs L3_Erector r = 0.506; L3_Erector vs Psoas r = 0.419) and with demographics; older pts had greater fat percentages (r = 0.31–0.45) and BMIs (r = 0.24–0.51). Increased FI at T2, T10, and L3 was associated with increased pelvic retroversion (PT: r = 0.25–0.43), global deformity (TPA: r = 0.27–0.45), and anterior malalignment (SVA: r = 0.23–0.41). The degree of FI in the PVM increased with the severity of SRS-Schwab PT and SVA modifiers. Conclusion In ASD patients, global sagittal malalignment is related to FI of the PVM throughout the lumbar and thoracic spine, as identified through CT. Future research should investigate how FI relates to ASD pathogenesis.

The relationship between clinical examination measures and ultrasound measures of fascia thickness surrounding trunk muscles or lumbar multifidus fatty infiltrations: An exploratory study

“…Why was pelvis flexion ROM also involved in the present regression model? Again, only LuM MFI (not fibrosis) would explain the positive relationship with ECHO LuM , as an increased MFI in the posterior vertebral muscles (erector spinae + LuM) has been associated with pelvic retroversion (Elysee et al, 2021; Lee et al, 2022; Zhang et al, 2021). However, MFI in LuM was not enough to induce a change in pelvic inclination in 93 healthy controls (Menezes‐Reis et al, 2018), which was later confirmed in a study showing a relationship with the erector spinae MFI but not LuM MFI in participants with spinal deformity (Miura et al, 2021).…”

Comparison of multifidus degeneration between scoliosis and lumbar disc herniation

“…Power analysis was based on data of previous studies on the infiltration rate of LDH and scoliosis [ 14 , 15 ] and showed that at least 23 patients were needed in each group to reach a high statistical power (> 0.8). After applying inclusion and exclusion criteria we enrolled 50 patients in our analysis.…”

Increased vertebral bone marrow fat content can be associated with vertebral fractures and back pain

“…Increased vertebral bone marrow fat content can be associated with vertebral fractures and back pain spine in patients with adult spinal deformity (17). And in relation to this, numerous studies have demonstrated a relationship between sagittal spinal imbalance and back pain (18,19).…”

“…In this sense, some authors have demonstrated an association between lumbar vertebral BMF content and paraspinal muscle fat composition ( 13 , 14 ), and at the same time a correlation between paraspinal muscle fat infiltration with a higher number of vertebral fractures and a lower BMD ( 14 - 16 ). It is worth highlighting the study published by Elysee et al where the authors found that global sagittal malalignment is related to fat infiltration of the posterior vertebral musculature throughout the lumbar and thoracic spine in patients with adult spinal deformity ( 17 ). And in relation to this, numerous studies have demonstrated a relationship between sagittal spinal imbalance and back pain ( 18 , 19 ).…”