The impact of posterior epidural adipose tissue on postoperative outcomes after posterior decompression surgery for lumbar spinal stenosis: A prospectively randomized non-inferiority trial

Abstract

Study design: The present study is a prospectively randomized study. Objective: The objective of the study was to evaluate the impact of posterior epidural adipose tissue (PAT) on postoperative outcome following lumbar decompression surgery for lumbar spinal stenosis (LSS) by whether PAT was removed or preserved during the surgical procedure. Summary of background data: In posterior decompression surgery for LSS, PAT is routinely removed without knowledge of its role and significance. However, considering adipose tissue has regenerative properties of damaged neighboring tissues or itself, PAT, which is adipose tissue located at peridural space, might also have a potential to regenerate the neighboring damaged tissue, including dura and nerve root in the lumbar spine, but this has not been thoroughly studied. Methods: Of the 185 eligible patients screened for the current study, 181 patients were enrolled and randomly allocated into either group A (PAT removal, n ¼ 90) or group B (PAT retention, n ¼ 91). The primary outcome measure was pain intensity on the lower back and lower extremity. The secondary outcome measures were functional outcome based on the Oswestry disability index (ODI) and walking distance, complications during the surgical procedure, and surgical outcomes. Results: Postoperative pain intensity on the lower back and lower extremity was greater in group A than in group B. Functional status on ODI and walking distance was also worse in group B than in group A (64.9% in group A and 66.2% in group B). The number of patients with aggravated pain intensity and deteriorated functional status in postoperative follow-up times was significantly greater in group A than in group B. There were no significant differences in surgical outcome and complications between the groups. Conclusion: Preserving epidural fat may be favorable in postoperative outcomes of posterior decompression surgery for LSS compared to removing epidural fat.

Isolation and Characterization of Extracellular Vesicle from Mesenchymal Stem Cells of the Epidural Fat of the Spine

“…Although some studies have suggested the histopathological features of the EF, subsequent studies have rarely reported a better definition of its function. Spine physicians rarely pay attention to EF, and it is mostly linked to epidural fibrosis formation after spinal surgery [17][18][19][20][21][22][23][24][25][26] and clinically uncharacterized back pain [24,27,28]. Recently, novel studies with different views on EF have focused on its regenerative or immunomodulatory function, especially with respect to MSCs derived from EF.…”

Comparisons of Extracellular Vesicles from Human Epidural Fat-Derived Mesenchymal Stem Cells and Fibroblast Cells

“…Adipose tissue has been shown to represent a rich source of MSCs, and studies have shown that EVs derived from human adipose tissue MSCs can be used to ameliorate tissue damage in various disease models [ 13 , 14 , 15 ]. Epidural fat tissue is inevitably exposed during spinal surgery and spontaneously diminishes after spinal surgery [ 23 ]. Recently, the need for research on the characteristics and functions of epidural fat tissue has emerged.…”

“…It has been possible to extract EVs from epidural adipose-derived mesenchymal stem cells, and such EVs have been confirmed to exhibit anti-inflammatory effects in a spinal cord injury animal model [ 21 ]. The epidural fat surrounds the dura matter of the spinal cord or nerve root [ 22 , 23 ]. However, the role and function of epidural fat are not clearly understood.…”

Epidural fat mesenchymal stem cells: Important microenvironmental regulators in health, disease, and regeneration

“…[ 59 ] Although epidural fat is often decreased in the stenotic area, [ 49 ] posterior decompression for treatment of lumbar spinal stenosis includes further removal of posterior epidural fat. [ 60 ] Kyphoscoliosis is a combination of both kyphosis and scoliosis (abnormal outward and lateral curvature of the spine, respectively). This condition leads to asymmetrical distribution of epidural fat within the concave portion of the spinal curvature, ultimately displacing the spinal canal and its contents in the opposite direction.…”

“…[ 61 ] In another study, following lumbar decompression surgery for lumbar spinal stenosis, postoperative outcomes worsened (pain intensity and a deteriorated score on the Oswestry (low back) Disability Index) amongst the group whose posterior epidural fat was removed. [ 60 ]…”