Spinal epidural lipomatosis: a rare association of Cushing's disease

Role of epidural fat in the local milieu: what we know and what we don't

PURPOSE

Traditionally, the epidural fat (EF) is known as a physical buffer for the dural sac against the force and a lubricant facilitating the relative motion of the latter on the osseous spine. Along with the development of the studies on EF, controversies still exist on vital questions, such as the underlying mechanism of the spinal epidural lipomatosis. Meanwhile, the scattered and fragmented researches hinder the global insight into the seemingly dispensable tissue.

METHODS

Herein, we reviewed literature on the EF and its derivatives to elucidate the dynamic change and complex function of EF in the local milieu, especially at the pathophysiological conditions. We start with an introduction to EF and the current pathogenic landscape, emphasizing the interlink between the EF and adjacent structures. We generally categorize the major pathological changes of the EF into hypertrophy, atrophy, and inflammation.

RESULTS AND CONCLUSIONS

It is acknowledged that not only the EF (or its cellular components) may be influenced by various endogenic/exogenic and focal/systematic stimuli, but the adjacent structures can also in turn be affected by the EF, which may be a hidden pathogenic clue for specific spinal disease. Meanwhile, the unrevealed sections, which are also the directions the future research, are proposed according to the objective result and rational inference. Further effort should be taken to reveal the underlying mechanism and develop novel therapeutic pathways for the relevant diseases.

Outcome of posterior decompression for spinal epidural lipomatosis

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.

[Clinical research progress of spinal epidural lipomatosis]

Objective

To review the clinical research progress of spinal epidural lipomatosis (SEL).

Methods

The clinical studies on SEL at home and abroad in recent years were extensively reviewed, and the pathogenesis, clinical and imaging manifestations, and treatment status of SEL were summarized and analyzed.

Results

SEL is a disease characterized by compression of the spinal cord and nerve roots due to abnormal accumulation of epidural adipose tissue in the spinal canal. Its prevalence and diagnosis rate are low and the pathogenesis is not fully understood. MRI is the most sensitive and specific diagnostic test for SEL. Surgical decompression and removal of excess adipose tissue are the only options for patients with acute SEL or those who have failed conservative management, and conservative management should be considered for other patients.

Conclusion

SEL is a rare disease and related research still needs to be improved. In the future, high-quality, multi-center and large-sample studies will be of great significance for evaluating the choice of treatment methods and effectiveness of SEL patients.

Spinal epidural lipomatosis: a rare and frequently unrecognized complication of Cushing syndrome

CONTEXT

Spinal Epidural Lipomatosis (SEL) is a rare and frequently unrecognized complication of Cushing syndrome (CS). Only nine previous cases of SEL have been described in CS. Here, we present a case of severe SEL and review the literature.

CASE REPORT

A 29-year-old man who had severe CS secondary to an ACTH-secreting pituitary macroadenoma. He presented with progressive lower limb weakness over a 2-year period leading to complete paraplegia in the last 4 months. In addition, he had classic symptoms and signs of severe CS. His evaluation confirmed the diagnosis of CS with a 4-fold increase in his daily free urinary cortisol (1190 mg/day), a positive 1-mg dexamethasone suppression test (AM cortisol 729 nmol/l) and an elevated ACTH of 196 ng/dl (10-65). Magnetic resonance imaging (MRI) revealed a 20-mm pituitary adenoma and extensive fat accumulation in the spinal canal extending from C7 to S5 with significant spinal cord compression from T2-T10. The patient underwent an urgent spinal cord decompression surgery. He showed an immediate improvement and was able to walk with crutches 3 weeks later and independently 3 months later. About 13 days after the spinal surgery, he underwent a trans-sphenoidal surgery resulting in eucortisolemia.

CONCLUSION

SEL is a rare and serious complication of CS. It should be considered in any patient with CS, especially when there is neurological symptoms or disproportionate weakness of the lower limbs. Its management should be individualized but prompt surgical decompression should be considered even in patients with relatively long history of paraparesis.

Spinal Epidural Lipomatosis: A Comprehensive Review

Purpose of review

This is a comprehensive review regarding the epidemiology, diagnosis, and management of spinal epidural lipomatosis (SEL).

Recent Findings

SEL is a relatively rare condition that has gained scientific relevance over the past few decades. Recent findings include expanding treatment strategies to include minimally invasive surgical techniques.

Summary

SEL is caused by an excess of adipose tissue accumulation localized to the thoracic and lumbar regions of the spine. While the exact pathogenesis is not fully elucidated, the etiology of SEL can be broadly classified based on five commonly associated risk factors; exogenous steroid use, obesity, endogenous steroid hormonal disease, spine surgery, and idiopathic disease. Progression of SEL may lead to neurological deficits, myelopathy, radiculopathy, neurogenic claudication, loss of sensation, difficulty voiding, lower extremity weakness, and rarely cauda equina syndrome. Conservative management is largely patient-specific and aimed at mitigating symptoms that arise from shared risk factors. If more advanced treatment measures are necessary, minimally invasive surgery and open surgical techniques, have proven successful.