The Fatty Degeneration of the Lumbar Erector Spinae Muscles Affects Dynamic Spinal Compensation Ability During Gait in Adult Spinal Deformity

Abstract

This study aimed to investigate whether fat infiltration in lumbar back muscles assessed by magnetic resonance imaging (MRI) could be related to dynamic sagittal spino-pelvic balance during gait in adult spinal deformity (ASD). This is a retrospective analysis of 28 patients with ASD. The fat infiltration rate of lumbar erector spinae muscles and multifidus muscles was measured by T2 weighted axial MRI at L1-2 and L4-5. Dynamic sagittal spinal and pelvic angles during gait were evaluated using 3D motion analysis. The correlation between fat infiltration rate of those muscles with variations in dynamic kinematic variables while walking and static radiological parameters was analyzed. Spinal kyphosis and pelvic anteversion significantly increased during gait. Fat infiltration rate of erector spinae muscles at L1-2 was positively correlated with thoracic kyphosis (r=0.392, p=0.039) and pelvic tilt (r=0.415, p=0.028). Increase of spinal kyphosis during walking was positively correlated with fat infiltration rate of erector spinae muscles both at L1-2 (r=0.394, p=0.038) and L4-5 (r=0.428, p=0.023). Qualitative evaluation of lumbar erector spinae muscles assessed by fat infiltration rate has the potential to reflect dynamic spino-pelvic balance during gait.

Preoperative Association Between Quantitative Lumbar Muscle Parameters and Spinal Sagittal Alignment in Lumbar Fusion Patients

“…MRI-based lumbar muscle measurements have become the principal method to assess the quantity and quality of spinal muscles, although methodological differences in image analysis exist that may impair the comparability of study results. [19][20][21]28,[40][41][42][43] Several studies assessed lumbar muscle parameters in patients with acute or chronic low back pain (LBP), the latter is a hallmark symptom of patients who ultimately undergo lumbar fusion that affected at least 87% of our study population. The multifidus muscle in particular has been linked to nociceptive chronic LBP through reflex inhibition of motor control to this key stabilizing muscle, resulting in functional instability and vertebral joint overload which further promotes pain.…”

“…Previous studies assessing lumbar muscles and spinopelvic parameters focused on patient populations with considerable sagittal or coronal deformity, such as in adult spinal deformity, [40][41][42] lumbar kyphosis, 19,22 lumbar flat back, 20 or lumbar scoliosis, 21 but small sample sizes and methodological issues, like the absence of any adjustments for potential confounders (e.g., age and BMI), must be critically considered. Whether these muscle parameters actively contribute to the development of sagittal imbalance as a causative factor or are the result of long-lasting sagittal imbalance, with an acquired inability of extensor muscles to counteract the deformity at some point, needs to be further investigated.…”

“…MRI-based lumbar muscle measurements have become the principal method to assess the quantity and quality of spinal muscles, although methodological differences in image analysis exist that may impair the comparability of study results 19–21,28,40–43. Several studies assessed lumbar muscle parameters in patients with acute or chronic low back pain (LBP), the latter is a hallmark symptom of patients who ultimately undergo lumbar fusion that affected at least 87% of our study population.…”

The relationship between spinal alignment and activity of paravertebral muscle during gait in patients with adult spinal deformity: a retrospective study

“…Recently, the analysis of dynamic spinal alignment and compensatory mechanisms have been reported for maintaining standing and walking positions in patients with ASD [8][9][10][11][12][13]. Walking load worsens spinal balance compared to a static standing posture [14], and spinal alignment in patients with ASD becomes unbalanced during gait [15].…”

“…Walking disrupts the compensatory mechanisms during standing posture and causes discrepancies in spinal alignment. Recent studies have reported the importance of paravertebral muscle assessment during this spinal alignment change [8,10,12,16]. As sagittal spinal unbalance occurs during walking, the trunk muscle group tries to respondto maintain spinal balance [5,7].…”