Outcome of posterior decompression for spinal epidural lipomatosis

Abstract

Background: In contrast to osteoligamentous lumbar stenosis (LSS), outcome of surgical treatment for spinal epidural lipomatosis (SEL) is still not well defined. We present risk factors for SEL and clinical long-term outcome data after surgical treatment for patients with pure SEL and a mixed-type pathology with combined SEL and LSS (SEL+LSS) compared to patients with pure LSS.

Methods: From our prospective institutional database, we identified all consecutive patients who were surgically treated for newly diagnosed SEL (n = 31) and SEL+LSS (n = 26) between 2018 and 2022. In addition, a matched control group of patients with pure LSS (n = 30) was compared. Microsurgical treatment aimed for posterior decompression of the spinal canal. Study endpoints were outcome data including clinical symptoms at presentation, MR-morphological analysis, evaluation of pain-free walking distance, pain perception by VAS-N/-R scales, and patient's satisfaction by determination of the Odom score.

Results: Patients with osteoligamentous SEL were significantly more likely to suffer from obesity (body mass index (BMI) of 30.2 ± 5.5 kg/m², p = 0.03), lumbar pain (p = 0.006), and to have received long-term steroid therapy (p = 0.01) compared to patients with SEL+LSS and LSS. In all three groups, posterior decompression of the spinal canal resulted in significant improvement of these symptoms. Patients with SEL had a significant increase in pain-free walking distance during the postoperative course, at discharge, and last follow-up (FU) (p < 0.0001), similar to patients with SEL+LSS and pure LSS. In addition, patients with pure SEL and SEL+LSS had a significant reduction in pain perception, represented by smaller values of VAS-N and -R postoperatively and at FU, similar to patients with pure LSS. In uni- and multivariate analysis, domination of lumbar pain and steroid long-term therapy were significant characteristic risk factors for SEL.

Conclusions: Surgical treatment of pure SEL and SEL+LSS allows significant improvement in pain-free walking distance and pain perception immediately postoperatively and in long-term FU, similar to patients with pure LSS.

Keywords: Posterior decompression; Spinal epidural lipomatosis; Spinal stenosis.

Fig. 1

Distribution of segment numbers according to SEL, SEL+LSS, and LSS. T, thoracic spine; L, lumbar spine; S, sacral spine

Fig. 2

MR imaging (sagittal and axial) of patients with SEL (a, b), SEL+LSS (c, d, e), and pure LSS (f, g). SEL is characterized by abnormal overgrowth of adipose tissue in the epidural space (red arrows, b). The mixed pathology (SEL+LSS) shows in addition to excessive overgrowth of epidural fat in one segment (green arrows, d) also lumbar spinal stenosis due to hypertrophied ligamenta flava in another segment (green arrows, e), whereas in pure LSS, only ligamenta flava thickening is detectable (blue arrows, g)

Fig. 3

Illustration of walking distance differences for patients with pure SEL (a), SEL+LSS (b), and pure LSS (c). ^****p < 0.0001, ^***p = 0.001, ^**p = 0.008

Fig. 4

VAS-N for patients with SEL (a), SEL+LSS (b), and LSS (c) preoperatively, postoperatively, and at FU. ^****p < 0.0001, ^*p = 0.01

Fig. 5

VAS-R for patients with SEL (a), SEL+LSS (b), and LSS (c) preoperatively, postoperatively, and at FU. ^****p < 0.0001, ^**p = 0.008

Fig. 6

Odom score differences (*p = 0.04)