Lumbosacral epidural lipomatosis: MRI grading

Acute neurologic decline in a patient with spinal stenosis: blame it on the epidural fat

Spinal epidural lipomatosis [SEL] is defined as an excessive accumulation of extradural normal adipose tissue. This condition may be idiopathic or acquired. Surgical decompression is considered the gold standard treatment in patients presenting with progressive neurologic deficit. We report a case of a 69-year-old male patient presented with neurogenic claudication and lower left limb radiculopathy. The magnetic resonance imaging (MRI) revealed a L5-S1 epidural compression sustained by a large epidural plaque whose signal was consistent with adipose tissue. A conservative approach, including weight loss attempt, revealed unsuccessful and the patient presented some months after the diagnosis at the emergency department with acute onset bilateral drop foot, more severe on the right side and urinary disturbances. Microsurgical decompression via L5 laminectomy and partial L4 laminectomy and fatty plaque debulking was performed. The post operative course was uneventful and at the two months post operative follow up the patient reported a significative improvement of the pre operative neurological signs and symptoms and of pain control. SEL deserves attention as an identifiable cause of radiculopathies, typically attributed to spinal stenosis, with a higher incidence than previously reported. Moreover cases of acute onset of cauda equina like syndrome were reported in patent affected by SEL, probably related to a local venous engorgement with stasis and edema. Therefore it should be considered as a possible diagnosis not only in patients complaining of stenosis-type symptoms but also in cases of acute neurological decline with cauda equina like syndrome, especially when provided with a "benign" imaging reading.

Extravertebral low back pain: a scoping review

BACKGROUND

Low back pain (LBP) is one of the most common reasons for consultation in general practice. Currently, LBP is categorised into specific and non-specific causes. However, extravertebral causes, such as abdominal aortic aneurysm or pancreatitis, are not being considered.

METHODS

A systematic literature search was performed across MEDLINE, Embase, and the Cochrane library, complemented by a handsearch. Studies conducted between 1 January 2001 and 31 December 2020, where LBP was the main symptom, were included.

RESULTS

The literature search identified 6040 studies, from which duplicates were removed, leaving 4105 studies for title and abstract screening. Subsequently, 265 publications were selected for inclusion, with an additional 197 publications identified through the handsearch. The majority of the studies were case reports and case series, predominantly originating from specialised care settings. A clear distinction between vertebral or rare causes of LBP was not always possible. A range of diseases were identified as potential extravertebral causes of LBP, encompassing gynaecological, urological, vascular, systemic, and gastrointestinal diseases. Notably, guidelines exhibited inconsistencies in addressing extravertebral causes.

DISCUSSION

Prior to this review, there has been no systematic investigation into extravertebral causes of LBP. Although these causes are rare, the absence of robust and reliable epidemiological data hinders a comprehensive understanding, as well as the lack of standardised protocols, which contributes to a lack of accurate description of indicative symptoms. While there are certain disease-specific characteristics, such as non-mechanical or cyclical LBP, and atypical accompanying symptoms like fever, abdominal pain, or leg swelling, that may suggest extravertebral causes, it is important to recognise that these features are not universally present in every patient.

CONCLUSION

The differential diagnosis of extravertebral LBP is extensive with relatively low prevalence rates dependent on the clinical setting. Clinicians should maintain a high index of suspicion for extravertebral aetiologies, especially in patients presenting with atypical accompanying symptoms.

Case Report: Technical description and clinical evaluation of three cases of unilateral biportal endoscopic decompression for symptomatic spinal epidural lipomatosis

Objective

To investigate the clinical characteristics and outcomes of three patients with symptomatic Spinal epidural lipomatosis (SEL) treated using Unilateral Biportal Endoscopic (UBE) surgery.

Methods

This report retrospectively analyzed the clinical data of three patients with SEL admitted to our hospital. The analysis covers onset characteristics, clinical manifestations, and the most recent radiologic grading system of neural compression (Manjila classification). Furthermore, it details the decompression accomplished through the application of a minimally invasive UBE surgical technique, specifically targeting the removal of proliferated fat responsible for nerve and spinal cord compression.

Results

This technique was performed successfully in 3 patients with SEL. Radiating pain was reduced, and the functional disability and radiologic compression were improved in all three patients. Postoperative spinal instability and surgical complications related to the procedure were not observed.

Conclusions

For SEL, timely diagnosis and appropriate intervention can prevent the progression of neurological disability. UBE is a minimally invasive muscle-preserving technique that achieves neural decompression directly by the removal of excessive intraspinal adipose tissue buildup.

Neurologic pathologies of the vertebral spine

At some institutions, musculoskeletal and general radiologists rather than neuroradiologists are responsible for reading magnetic resonance imaging (MRI) of the spine. However, neurological findings, especially intrathecal ones, can be challenging. Intrathecal neurological findings in the spine can be classified by location (epidural, intradural extramedullary, and intramedullary) or etiology (tumor, infection, inflammatory, congenital). In this paper, we provide a succinct review of the intrathecal neurological findings that can be seen on MRI of the spine, primarily by location and secondarily by etiology, in order that this may serve as a helpful guide for musculoskeletal and general radiologists when encountering intrathecal neurological pathologies.

Metabolic syndrome: imaging features and clinical outcomes

Metabolic syndrome, which affects around a quarter of adults worldwide, is a group of metabolic abnormalities characterized mainly by insulin resistance and central adiposity. It is strongly correlated with cardiovascular and all-cause mortality. Early identification of the changes induced by metabolic syndrome in target organs and timely intervention (eg, weight reduction) can decrease morbidity and mortality. Imaging can monitor the main components of metabolic syndrome and identify early the development and progression of its sequelae in various organs. In this review, we discuss the imaging features across different modalities that can be used to evaluate changes due to metabolic syndrome, including fatty deposition in different organs, arterial stiffening, liver fibrosis, and cardiac dysfunction. Radiologists can play a vital role in recognizing and following these target organ injuries, which in turn can motivate lifestyle modification and therapeutic intervention.

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.

Postpartum Spinal Epidural Lipomatosis With Epidural Venous Engorgement

Spinal epidural lipomatosis (SEL) refers to a condition characterized by the abnormal growth of fatty tissue within the vertebral canal, situated outside the spinal canal itself. This expansion of fat can result in symptoms such as back pain and radiculopathy. The majority of cases remain without noticeable symptoms. However, when SEL does cause symptoms, it is frequently linked to using external steroids. The contributing factors to SEL include obesity and Cushing's syndrome. The presentation of SEL can mimic other spinal disorders such as epidural hematoma, spinal stenosis, and degenerative joint disease. Patients might present with gradually progressing and long-standing complaints of back pain, muscle weakness, numbness, loss of bladder or bowel control, lack of coordination, abnormal reflexes, and, in rare instances, paralysis. We are reporting a case involving a 34-year-old female with obesity, who experienced sudden weakness in her left lower extremity shortly after a recent uncomplicated vaginal delivery using epidural analgesia. A magnetic resonance imaging (MRI) of her thoracic (T) and lumbar spine revealed spinal cord compression secondary to extensive posterior epidural lipomatosis associated with epidural venous engorgement. The patient underwent an immediate laminectomy procedure at the T3, T5, T7, and T9 levels to alleviate the compression. Postoperatively, she underwent a course of physiotherapy and gradually regained her normal muscle strength. She was discharged in stable condition on the sixth day after the surgery.

Correlation of spinal epidural fat volume with body mass index: a longitudinal study

PURPOSE

Spinal epidural lipomatosis is abnormal accumulation of normal fat in the epidural space with weight loss suggested as first-line therapy in select symptomatic patients. However, moderate to large longitudinal studies establishing concordant changes between body mass index and epidural fat are lacking. The purpose of this study was to longitudinally assess this relationship.

METHODS

We performed an ancillary study of the Habitual Diet and Avocado Trial. Baseline and six-month abdominal MRIs were analyzed for 98 overweight or obese but otherwise healthy subjects. Dorsal epidural fat volumes in the lumbar spine were measured and correlated with changes in body mass index, changes in visceral fat volume, and demographic information.

RESULTS

There was a linear relationship between body mass index changes and epidural fat volume changes with a one-point change in body mass index corresponding to a 45 mm³ change in dorsal epidural fat volume (p < 0.001, 95% CI 31.87 to 76.77) as well as between visceral fat volume changes and epidural fat volume changes (regression coefficient 0.51, p < 0.001, 95% CI 0.22 to 0.47). Age was inversely related with subjects older than 45.7 years tending to lose epidural fat (regression coefficient -0.22, p = 0.025, 95% CI -10.43 to -0.72).

CONCLUSION

Changes in spinal dorsal epidural fat volume parallel changes in body mass index and visceral fat, supporting weight loss as initial treatment for uncomplicated obesity-associated spinal epidural lipomatosis.

The Mysterious Role of Epidural Fat Tissue in Spine Surgery: A Comprehensive Descriptive Literature Review

BACKGROUND

Though both neurosurgeons and orthopedic spinal surgeons are keenly aware of the clinical importance of epidural fat (EF), surgical practice varies amongst individual surgeons and across both fields. Thus, an in-depth understanding of the anatomical structure and composition of EF is vital, as it will play a significant role in the therapeutic management and the surgical choice of treatment.

OBJECTIVE

We aim to extensively review the anatomical and biological properties of EF and further outline the surgical importance of EF management.

STUDY METHODOLOGY

(i) MEDLINE search 1966-July 2019. Keywords: Review of the Literature. Authorship, Meta-analysis, Descriptive/Narrative overview; (ii) CINAHL search from 1982 to May 2019. Keywords: Review of the Literature spinal epidural fat; Authorship; Meta-analysis; Descriptive/Narrative overview; (iii) Hand searches of the references of retrieved literature; (iv) Personal and college libraries were searched for texts on research methods and literature reviews; and (v) 200 articles were downloaded, 50 were excluded because of similarity of topics and also because of new update on the same topics. (vi) Discussions with experts in the field of reviews of the literature.

DISCUSSION

Though excessive or reductive amounts of EF usually exacerbates neurological symptoms and lead to various pathologic conditions such as spinal epidural lipomatosis, but there is no basic science, experimental, or clinical research that proves the role of EF in the aforementioned pathologic situations.

CONCLUSION

Anatomical illustration, biological function and properties of EF knowledge may lead to changes in the stages of the surgical approach to avoid postoperative complications. However, the role of EF is exclusively bound to a scientific hypothesis as one cannot be sure if an excessive or reductive amount in EF is entirely responsible for the pathologic findings, or just only an incidental finding.

Could Spinal Epidural Lipomatosis Be the Hallmark of Metabolic Syndrome on the Spine? A Literature Review with Emphasis on Etiology

Spinal epidural lipomatosis is defined by an excessive amount of epidural fat in the spinal canal, usually in the lumbosacral tract: a well-known cause of lumbar pain and spinal stenosis with a possible wide range of neurological symptoms. Recent research data reveal that, nowadays, obesity has become the main cause of spinal epidural lipomatosis. Moreover, this condition was recently recognized as a previously unknown manifestation of metabolic syndrome. Radiological studies (CT and MRI) are the only tools that are able to diagnose the disease non-invasively. Indeed, radiologists play a key role in disease recognition, with subsequent possible implications on patients' systemic health assessments. Despite its clinical importance, the condition is still underreported and neglected. The current literature review summarizes all the main etiologies of spinal epidural lipomatosis, particularly regarding its linkage with metabolic syndrome. An overview of disease characteristics from diagnosis to treatment strategies is also provided.

Imaging of muscle and adipose tissue in the spine: A narrative review

Interpretation of the morphology and characteristics of soft tissues, such as paravertebral muscles and fat, has always been a "relative blind spot" in the spine. The imaging features of the non-bony structures of the spine have been studied and reinterpreted, and changes in the non-bony structure are associated with spinal disease. Soft tissue parameters such as, the "paraspinal muscle cross-sectional area," "subcutaneous fat thickness," and the "paraspinal muscle fat infiltration rate" on computed tomography, magnetic resonance imaging and other imaging techniques are reproducible in the diagnosis, treatment and prognosis of spinal disorders and have the potential for clinical application. In addition, focus on the association between sarcopenia and spinal epidural lipomatosis with spinal disorders is increasing. Currently, there is no summary of studies on fat and muscle in the spinal region. Given this, within the context of recent research trends, this article provides a synthesis of research on adipose and muscle tissue in the spine, discusses advances in the study of the imaging manifestations of these structures in spinal disorders, and expands the perspectives.

Spinal Epidural Lipoma on the Ventral Dura Side and Intervertebral Foramen Causing Lumbar Radiculopathy

A 56-year-old obese man with a body mass index of 30.9 kg/m² presented with left sciatica and intermittent claudication. Computed tomography scans showed a posterior vertebral scalloping change in L3, L4, and L5. Meanwhile, magnetic resonance imaging revealed epidural mass posterior to the L3, L4, and L5 vertebral bodies. The solitary mass was isosignal to subcutaneous fat and asymmetrically compressed to the left side of the dural sac and L4 nerve root, as observed on axial T1- and T2-weighted images. To the best of our knowledge, there have been few reports of a solitary epidural lipoma causing lumbar radiculopathy. The patient underwent transforaminal lumbar interbody fusion at L4-L5, and his symptoms then resolved. Thus, we recommend decompression and fixation as appropriate management for lumbar radiculopathy caused by epidural lipoma located on the ventral side of the dura and intervertebral foramen.

Ligamentum flavum hypertrophy significantly contributes to the severity of neurogenic intermittent claudication in patients with lumbar spinal canal stenosis

Ligamentum flavum hypertrophy (LFH) is a known contributor to lumbar spinal canal stenosis (LSCS). However, the clinical significance and quantitative role of LFH compared to other components, such as disc bulging and facet hypertrophy, have not yet been examined. We investigated the correlation between the quantitative radiological factors, clinical symptoms, and outcomes in patients with LSCS. In total, 163 patients diagnosed with single-level (L4-L5) stenosis were included. The patients were divided into 2 groups according to claudication severity: >100 m for mild (n = 92) and < 100 m for severe (n = 71). The visual analog scale (VAS) was used to quantify back and leg pain, and the Oswestry Disability Index (ODI) and Short form-36 (SF-36) physical component summary (PCS) scores, and Macnab criteria were evaluated as clinical factors 6 months after treatment. We measured the baseline canal cross-sectional area, ligamentum flavum (LF) area, disc herniation area, dural sac area, fat area, and LF thickness using MRI. A comparative analysis was performed to evaluate the association between radiologic and clinical factors. Additionally, further comparative analyses between the types of surgeries were performed. Among various radiologic factors, the baseline LF thickness (odds ratio [OR] 1.73; 95% confidence interval [CI] 1.25-2.41) was the only major contributing factor to the severity of claudication in the multivariate logistic regression analysis. The types of surgery (decompression alone vs fusion) did not significantly differ in terms of their clinical outcomes, including back and leg VAS, ODI, SF-36 PCS, and satisfaction with the MacNab classification. LF thickness is a major factor contributing to claudication severity.

Percutaneous full-endoscopic uniportal decompression for the treatment of symptomatic idiopathic lumbar spinal epidural lipomatosis: Technical note

Background

Lumbar spinal epidural lipomatosis (SEL) is a rare condition characterized by an excessive accumulation of adipose tissue within the spinal canal, compressing the dura sac and/or nerve roots. When conservative treatments fail and clinical symptoms progress quickly and seriously, surgical decompression should be considered. With the rapid development of endoscopic armamentaria and techniques, the pathological scope that can be treated by percutaneous endoscopic spine surgery is ever expanding.

Objective

In this paper, the authors describe a patient with lumbar spinal epidural lipomatosis who was treated with a percutaneous full-endoscopic uniportal decompression surgery successfully. This article aims to validate the feasibility of percutaneous full-endoscopic uniportal decompression for the treatment of symptomatic idiopathic spinal epidural lipomatosis via interlaminar approach.

Methods

We describe a case of a 69-year-old man with a 10-year history of low back pain, intermittent claudication, and bilateral leg neuropathic pain. He was diagnosed with lumbar epidural lipomatosis, which did not respond to conservative therapy. After a comprehensive evaluation, he underwent percutaneous endoscopic spine surgery to remove hyperplastic adipose tissue and decompress nerve roots and dura sac.

Results

The patient was treated with a percutaneous full-endoscopic uniportal decompression surgery successfully. After the procedure, his leg pain decreased and his walking capacity improved. There were no surgery-related complications, such as cerebrospinal fluid leakage, incision infection, etc.

Conclusions

The case with SEL was successfully treated with a percutaneous full-endoscopic uniportal surgery, which has the advantages of excellent presentation of anatomical structures, expanded field of vision, less surgical-related trauma, and bleeding. The key point of the procedure is to release and cut off the bands which divide the epidural space into small rooms filled with excess adipose tissue.

Clinical and radiological characteristics of spinal epidural lipomatosis: A retrospective review of 90 consecutive patients

Background

The epidemiology and clinical characteristics of spinal epidural lipomatosis (SEL) have been well-reported in the literature. However, few studies investigated the concomitant spinal pathologies that were present in patients with SEL. Therefore, we aimed to summarize the clinical and radiological characteristics of patients with SEL diagnosed on spinal imaging.

Methods

Patients who were diagnosed with SEL on magnetic resonance imaging from January 2018 to October 2020 at our institution were included in the study. Clinical data was collected using a standardized data collection form. SEL was graded using a modified version of the Borré grading system. Factors associated with moderate or severe SEL were determined using multiple logistic regression.

Results

A total of 90 patients were included in the analysis. The mean (±SD) age was 59.3 (±17.1) years, and 62 patients (68.9%) were male. 61 patients (67.8%) had moderate or severe SEL. Most patients were overweight or obese (57 patients, 63.3%). The most common presenting symptoms was back pain (57 patients, 63.3%). SEL was diagnosed incidentally in 42 patients (46.7%). The lumbar spine was the most common site of SEL (35 patients, 38.9%). The most common concomitant spinal pathologies were disc bulge (83 patients, 92.2%) and flavum hypertrophy (60 patients, 66.7%). Moderate or severe SEL was associated with WHO Obesity Class, back pain or radicular leg pain at first presentation, and SEL that was worst at the lumbar or lumbosacral spinal level.

Conclusions

Moderate or severe SEL were independently associated with WHO Obesity Class, back pain, radicular leg pain, and SEL that was worst at the lumbar or lumbosacral spinal level. Future studies should prospectively evaluate whether weight loss therapy is warranted in patients with SEL.

Spinal Epidural Lipomatosis Causing Lumbar Canal Stenosis: A Pictorial Essay on Radiological Grading and the Role of Bariatric Surgery Versus Laminectomy

Spinal epidural lipomatosis (SEL) is a rare condition characterized by an excessive accumulation of adipose tissue in the spinal canal that can have a compressive effect on intraspinal neuroanatomical structures, leading to clinical symptoms. Several different conservative and surgical treatment strategies have been proposed but the treatment and outcomes remain controversial. There is a lack of severity-based evidence documenting the success of decompressive laminectomy in SEL and there are only anecdotal reports of clinico-radiological success with weight loss from bariatric surgery. This article demonstrates the resolution of SEL in two patients with bariatric surgery with the help of pre and postoperative MR imaging. The authors also highlight the classic “types” of spinal epidural lipomatosis with a surgically relevant grading system and elucidate the existence of concurrent extraspinal lipomatosis (i.e. mediastinal and intra-abdominal lipomatosis), drawing parallels with the natural history of SEL. The controversial question remains whether a symptomatic SEL patient needs a multilevel laminectomy for spinal decompression or bariatric surgery that can indirectly help the spinal condition. We propose that bariatric intervention could be better frontline management in patients with multifocal/multisystem lipomatosis (i.e., combined spinal and extraspinal) and spinal decompression would be ideal for those SEL patients with coexisting bony and/or ligamentous spinal canal or foraminal stenosis. This manuscript serves as a comprehensive and contemporary update on the radiological profile and two plausible treatment paths and will look toward further verification by a randomized clinical trial.

Spinal epidural lipomatosis

Spinal epidural lipomatosis (SEL) is a rare pathologic growth of histologically normal nonencapsulated adipose tissue in the epidural space. It can cause myelopathy or radiculopathy. Etiologies include chronic exposure to endogenous or exogenous steroids and obesity. Idiopathic forms are much infrequent. We present a case of lumbar SEL compressing the thecal sac in a 50-year-old female patient.

Is there an association between lumbosacral epidural lipomatosis and lumbosacral epidural steroid injections? A comprehensive narrative literature review

Background

Exogenous systemic steroid exposure is a well-established risk factor for spinal epidural lipomatosis (SEL), however the association between lumbosacral epidural steroid injections (LESIs) and lumbosacral epidural lipomatosis (LEL) is generally regarded as poorly understood. Our objective was to investigate the rationale and the evidence implicating LESI(s) as a potential cause of LEL as well as the evidence related to use of LESI(s) as a potential pain relieving treatment option for radicular pain in the setting of LEL.

Methods

PubMed, Embase, Google Scholar, OVID were searched from inception until April 2021. Three investigators identified literature that provided original descriptive patient clinical data attributing the development/progression of LEL to LESI(s) or described the use of LESI(s) as a pain relieving modality for radicular pain in the setting of LEL.

Results

Fourteen publications were included for review. Overall, the current level of evidence is of low-quality. There are significant methodological gaps on this subject matter and many studies do not account for confounding variables independently associated with LEL.

Conclusions

This review has identified substantial limitations in the literature regarding that which is truly known regarding LESI(s) and LEL, as well as conservative management overall. To provide a well-rounded perspective, we synthesized literature as it pertains to: 1) current knowledge regarding SEL, notable associations and potential implications for corticosteroid exposure; 2) corticosteroid exposure and lipoatrophy; 3) current management recommendations for SEL and 4) areas for future focus. Although LESI(s) have been associated with LEL in the literature, presently due to a lack of rigorous, high-quality studies, the presence or absence of an independent causal relationship between LESI(s) and LEL cannot be stated with confidence.

A New Subform? Fast-Progressing, Severe Neurological Deterioration Caused by Spinal Epidural Lipomatosis

Spinal epidural lipomatosis (SEL) is a rare condition caused by hypertrophic growth of epidural fat. The prevalence of SEL in the Western world is approximately 1 in 40 patients and is likely to increase due to current medical and socio-economic developments. Rarely, SEL can lead to rapid severe neurological deterioration. The pathophysiology, optimal treatment, and outcome of these patients remain unclear. This study aims to widen current knowledge about this “SEL subform” and to improve its clinical management. A systematic literature review according to the PRISMA guidelines using PubMed, Scopus, Web of Science, and Cochrane Library was used to identify publications before 7 November 2021 reporting on acute/rapidly progressing, severe SEL. The final analysis comprised 12 patients with acute, severe SEL. The majority of the patients were male (9/12) and multimorbid (10/12). SEL mainly affected the thoracic part of the spinal cord (11/12), extending a median number of 7 spinal levels (range: 4–19). Surgery was the only chosen therapy (11/12), except for one critically ill patient. Regarding the outcome, half of the patients regained independence (6/11; = modified McCormick Scale ≤ II). Acute, severe SEL is a rare condition, mainly affecting multimorbid patients. The prognosis is poor in nearly 50% of the patients, even with maximum therapy. Further research is needed to stratify patients for conservative or surgical treatment.

Lumbar Epidural Lipomatosis is Increased in Patients With Morbid Obesity and Subsequently Decreases After Bariatric Surgery

BACKGROUND

Spinal epidural lipomatosis (SEL) is characterized by symptomatic neurogenic compression from adipose tissue in the spinal canal. The question arises whether patients with morbid obesity have higher volumes of epidural adipose tissue (EAT) in their lumbar spinal canal compared with patients with a normal weight, and to what extent this decreases after bariatric surgery.

METHODS

In this explorative study the lumbar EAT volume was assessed in 25 patients with morbid obesity (body mass index [BMI] >40) using available lumbar magnetic resonance imaging (MRI) prior to their bariatric surgery. An age- and sex-matched control group (n = 25) of patients with a normal weight (BMI 20-25) was used for comparison. Participants from the obesity group underwent a postoperative control MRI.

RESULTS

The mean volume of EAT per MRI slice of the group of patients with obesity was significantly higher than for the group of patients with normal weight (mean: 83.3 ± 30.7 mm³ vs. mean 56.5 ± 25 mm³; P < 0.001). Fifteen participants with obesity (15 of 25) agreed to undergo a follow-up MRI. There was a significant decrease in EAT volume per MRI slice for these 15 participants (mean 82 ± 25.5 mm³ vs. 46 ± 20.0 mm³; P < 0.001) over time up to 3.6 (range: 1.2-6.0) years after bariatric surgery.

CONCLUSIONS

Patients with obesity have significantly larger volumes of EAT in comparison with patients with normal weight. After bariatric surgery, a significant weight loss coincided with a significant volumetric reduction of this adipose tissue in the spinal canal. Future prospective studies in patients with symptomatic SEL may elucidate whether decreases in EAT volume influence concurrent neurogenic claudication symptoms.

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.

MRI Features and Clinical Significance of Spinal Epidural Lipomatosis: All You Should Know

Spinal epidural lipomatosis (SEL) is defined as the abnormal accumulation of unencapsulated adipose tissue in the spinal epidural space. SEL can be asymptomatic or can cause a wide range of symptoms, the most common of which is neurogenic claudication. Several other neurological manifestations may also occur, above all myelopathy and radicular symptoms. The spinal level most frequently involved in patients with SEL is the lumbar one, followed by the thoracic one. Imaging plays a key role in disease assessment. MRI is considered the most effective and sensitive modality for diagnosing and staging SEL. Anyway, also CT scan can diagnose SEL. The diagnosis may be incidental (in mild-moderate disease) or may be taken into account in cases with neurological symptoms (in moderate-severe disease). There are some recognized risk factors for SEL, the most common of which are exogenous steroid use and obesity. Recent studies have found an association between SEL and obesity, hyperlipidemia and liver fat deposition. As a matter of fact, SEL can be considered the spinal hallmark of metabolic syndrome. Risk factors control represents the initial treatment strategy in patients with SEL (e.g. weight loss, steroid therapy suspension). Surgical decompression may be required when conservative treatment fails or when the patient develops acute/severe neurological symptoms.

Lumbar laminotomy and replantation for the treatment of lumbar spinal epidural lipomatosis: A case report

RATIONALE

Lumbar spinal epidural lipomatosis (SEL) is a rare condition characterized by excessive overgrowth of extradural fat within the lumbar spinal canal. Surgical decompression is commonly performed to treat symptomatic SELs. Fenestration or laminectomy with epidural fat debulking was a routine surgical procedure according to the literature, that may be causing postoperative lumbar instability. In the present study, we presented a brief report of lumbar SEL and introduced another surgical approach.

PATIENT CONCERNS

A 55-year-old man complained of severe low back pain and right leg radicular pain for a year, accompanied by neurogenic intermittent claudication. He received a variety of conservative treatments, including non-steroidal anti-inflammatory drugs, acupuncture, and physical therapy. However, his pain did not diminish. Finally, a posterior epidural mass in the dorsal spine extending from the L3 to L5 level, which caused dural sac compression was found on lumbar magnetic resonance imaging. This mass was homogeneously hyperintense in both T1W1 and T2W1 images, suggestive of epidural fat accumulation.

DIAGNOSES

Lumbar SEL.

INTERVENTIONS

The patient underwent lumbar laminectomy, epidural fat debulking, and spinous process-vertebral plate in situ replantations.

OUTCOMES

The patient presented with complete recovery of radiculopathy and low back pain after surgery. Postoperative magnetic resonance imaging showed that the increased adipose tissue disappeared, and the dural sac compression was relieved. A computed tomography scan revealed the lumbar lamina in situ. He was able to walk normally and remained relatively asymptomatic for 12 months after the operation at the last follow-up visit.

LESSONS

Lumbar laminotomy and replantation provide an ideal option to treat lumbar SEL because it can achieve sufficient and effective decompression, simultaneously reconstruct the anatomy of the spinal canal, and reduce the risk of iatrogenic lumbar instability.

Lumbar spinal stenosis combined with obesity-induced idiopathic spinal epidural lipomatosis treated with posterior lumbar fusion: case report

BACKGROUND

Spinal epidural lipomatosis is a rare cause of lumbar spinal stenosis. While conservative therapy is applicable for most of cases, surgical intervention is necessary for severe ones. This is the first time we apply this modified technique to this disease.

CASE PRESENTATION

The case is a 53-year-old man. He is 175 cm tall and weighs 102 kg (body mass index 33.3 kg/cm²), presenting with low back pain and bilateral legs pain and numbness. Radiological examination showed severe lumbar spinal stenosis resulting from adipose hyperplasia, combined with hyperosteogeny and hypertrophy of ligaments, which are common etiological factors. Posterior decompression, internal fixation and a modified articular fusion technique was performed on this patient, and regular follow-up that up o 22 months showed outstanding clinical outcomes.

CONCLUSIONS

A suitable style of posterior lumbar fusion should be considered to especially severe case with lumbar spinal stenosis and idiopathic spinal epidural lipomatosis.

Resolution of Idiopathic Epidural Lipomatosis after Bariatric Surgery: Case Report and Literature Review

Spinal epidural lipomatosis (SEL) is traditionally a rare disorder defined as an abnormal accumulation of unencapsulated epidural fat. SEL can be classified into idiopathic and secondary. We report a 46-year-old obese male with idiopathic epidural lipomatosis with a clinical picture of bilateral L5 and S1 radiculopathy, with an L5 and S1 distribution. Magnetic resonance imaging (MRI) showed epidural lipomatosis at L4, L5, and S1. After 2-year of sleeve gastrectomy, his bilateral sciatic radiculopathy disappeared, and updated MRI showed complete resolution of epidural lipomatosis. We present a case of an unusual epidural lipomatosis, resolved completely by bariatric surgery. This case report set out the effect of metabolic surgery on the local and systemic metabolic process.

Lumbar spinal epidural lipomatosis: A case report and review of the literature

INTRODUCTION

Lumbar spinal epidural lipomatosis (SEL) is a rare condition defined by an excessive deposition of adipose tissue in the lumbar spinal canal. The objective of this case report is to document a clinical case of SEL presenting within a multidisciplinary spine clinic and to compare our clinical findings and management with the available literature.

CASE PRESENTATION

A 51-year-old female presented at a spine clinic with low back pain, bilateral leg pain and difficulty walking. Magnetic resonance imaging of the lumbar spine showed evidence of severe central canal stenosis due to extensive epidural lipomatosis. She was initially advised to lose weight and undergo a 3-month course of physiotherapy. However, because of lack of improvement, she was scheduled for and underwent L4-S1 posterior spinal decompression and L4-L5 posterior spinal instrumented fusion. At 12-month follow-up, the patient reported no pain and retained the ability to walk regular distances without experiencing discomfort.

DISCUSSION

This case report describes the conservative and surgical management of a case of lumbar spinal stenosis due to SEL. The therapeutic approach of patients with this condition is not standardized. As such, a discussion of the literature with respect to the diagnosis, clinical presentation, epidemiology, imaging appearance, risk factors, etiology, and management of SEL is also presented.

Clinical Implications of the Epidural Fat Thickness in the Management of Lumbar Spinal Stenosis

OBJECTIVE

Lumbar epidural lipomatosis is a rare condition defined as the excessive accumulation of epidural fat (EF). We herein investigated the indicators of the posterior compression factors, EF and yellow ligament, to identify the clinical features of lumbar epidural lipomatosis.

METHODS

Five hundred consecutive patients who underwent posterior lumbar decompression surgery for lumbar spinal stenosis (LSS) were retrospectively reviewed. The EF/SC-L index (the ratio of the anteroposterior length of the EF to that of the spinal canal [SC]) was evaluated at the spinal level that exhibited maximum dural tube compression. The participants were divided into 3 groups: grade I, EF/SC-L index ≤50%; grade II, EF/SC-L index 51%-74%; grade III, EF/SC-L index ≥75%. EF/SC-A (the ratio of the cross-sectional area of EF to that of SC) and YL/SC-A (the ratio of the cross-sectional area of yellow ligament [YL] to that of SC) were calculated. The clinical outcomes were assessed according to the Japan Orthopaedic Association scale for lumbar disease.

RESULTS

EF/SC-L exhibited a significantly positive correlation with EF/SC-A (r = 0.82, P < 0.001), and a negative correlation with YL/SC-A (r = -0.71, P < 0.001). The Japan Orthopaedic Association score recovery rate was 56.7 ± 22.6 in the case-matched control group, 34.5 ± 31.2 in the grade II group (P < 0.001), and 39.6 ± 24.9 in the grade III group (P = 0.032).

CONCLUSIONS

The EF/SC-L index is a simple and reliable indicator to quantitatively evaluate posterior compression in patients with LSS. As the accumulation of EF is associated with worse operative outcomes, the EF/SC-L index should be considered when planning lumbar decompression surgery for patients with LSS.

Lumbar Spinal Canal Stenosis from the Perspective of Locomotive Syndrome and Metabolic Syndrome: A Narrative Review

Patients with lumbar spinal canal stenosis (LSS) have impaired activities of daily living because of pain or motor paralysis, but no effective preventive treatment is currently available. The number of patients with LSS is predicted to continually increase as the average age of the global population increases. To provide a conceptual framework for improving healthy life expectancy, the Japanese Orthopaedic Association introduced the concept of locomotive syndrome, to which LSS is related. Ours and other studies have shown that LSS exacerbates locomotive syndrome and that surgical treatment is one method for improving it. Furthermore, we propose that the two-step test, a locomotive syndrome risk test, is effective for assessing the risk for falls and severity of LSS. Meanwhile, lumbar spinal epidural lipomatosis (LSEL), which is a manifestation of LSS, has been shown to be related to metabolic syndrome. Previous studies have suggested that the whole LSS can be also associated with metabolic syndrome. Although locomotive syndrome is very different from metabolic syndrome, which involves lipid metabolism, these two syndromes overlap, such as in LSS. Conducting research on LSS from the perspectives of both locomotive syndrome and metabolic syndrome may lead to novel methods for prevention and treatment of LSS and, conversely, may yield clues for resolving symptoms of the two syndromes. This review provides an overview of LSS from the perspective of locomotive syndrome and metabolic syndrome, along with findings from our research group.

Thoracic spine fracture associated with an extradural lipoma: Case report and systematic review of the literature

Isolated extradural lipoma (IEL), not associated to spinal dysraphisms, is a rare condition. Frequently IEL was confused with much more frequent diffuse lipomatosis. The lesion can be completely asymptomatic and occasionally diagnosed with magnetic resonance (MR) imaging. This paper describes a case of a patient with an axial compression fracture of the thoracic spine associated with an extradural lipoma. We also performed a systematic review of the pertinent literature in order to retrieve the key information regarding: the diagnosis, the clinical features and the treatment.

Two-year outcome comparison of decompression in 14 lipomatosis cases with 169 degenerative lumbar spinal stenosis cases: a Swiss prospective multicenter cohort study

PURPOSE

Spinal epidural lipomatosis (SEL) is defined as an abnormal and extensive accumulation of unencapsulated adipose tissue within the spinal epidural space. To date, there is a lack of high-level evidence studies reporting the outcome of surgical treatment of symptomatic SEL in patients with lumbar spinal stenosis (LSS). The aim was to compare clinical outcomes in patients with symptomatic LSS with and without SEL who underwent decompression surgery alone at the 12- and 24-month follow-up.

METHODS

One hundred and eighty-three patients met the inclusion criteria, of which 14 had mainly SEL on at least one level operated in addition to possible degenerative changes on other levels and 169 degenerative LSS only. The main outcomes were pain (Spinal Stenosis Measure (SSM) symptoms), disability (SSM function), and quality of life [EQ-5D-3L summary index (SI)] at 24-month follow-up, and minimal clinically important difference (MCID) in SSM symptoms, SSM function, and EQ-5D-3L SI.

RESULTS

The multiple regression linear models showed that SEL was associated with worse SSM symptoms (p = 0.045) and EQ-5D-3L SI scores (p = 0.026) at 24-month follow-up, but not with worse SSM function scores. Further, depression (in all models) was negatively associated with better clinical outcomes at 24-month follow-up. In the outcomes SSM symptoms and EQ-5D-3L SI, distinctly more patients in the classical LSS group reached MCID than in the SEL group (71.3% and 62.3% vs. 50.0% and 42.9%).

CONCLUSIONS

Our study demonstrated that decompression alone surgery was associated with significant improvement in disability in both groups at 2 years, but not in pain and quality of life in patients with SEL.

Idiopathic Epidural Lipomatosis Associated with Degenerative Discopathy: Grand Round Presentation of Unusual Lumbar Canal Stenosis Resolved by Weight Loss

Here, we report a case of idiopathic epidural lipomatosis presented with a clinical picture of lumbar canal stenosis with neurogenic claudication which resolved completely only by weight loss. A 53-year-old obese male with a body mass index of 36 without significant past medical history presented to the outpatient clinic with neurogenic claudication and bilateral sciatic radiculopathy. Initially, magnetic resonance imaging (MRI) showed epidural lipomatosis at the level of L5 vertebral body and L5–S1 intervertebral disc. A conservative treatment was decided with dietary regime program. After 6 months of follow-up, his bilateral sciatic radiculopathy disappeared, and updated MRI showed complete disappearance of epidural lipomatosis. Based on the Grand Round case and relevant literature, we present a case of an unusual epidural lipomatosis with mixed clinical picture of degenerative lumbar disease. This case report set out the importance of Borré classification for differentiating the mixed clinical complaint of degenerative discopathy and epidural lipomatosis.

Spinal Epidural Lipomatosis: A Rare Complication From Hormonal Therapy for Infantile Spasms

BACKGROUND

Spinal epidural lipomatosis (SEL) represents pathologic overgrowth of extradural adipose tissue in the spinal canal that can result in spinal cord compression. SEL has been associated with excess corticosteroids, whether from exogenous steroid use or from excess endogenous steroids. Spinal epidural lipomatosis is rarely reported in children and has not been reported in association with hormonal therapy for infantile spasms.

METHODS

We performed a detailed retrospective chart and literature review.

RESULTS

We describe two children with symptomatic SEL associated with the use of high-dose hormone treatment for infantile spasms.

Negative impact of spinal epidural lipomatosis on the surgical outcome of posterior lumbar spinous-splitting decompression surgery: a multicenter retrospective study

BACKGROUND CONTEXT

Spinal epidural lipomatosis (SEL) results from excess lumbar epidural fat (EF) accumulation that compresses the cauda equina or nerve roots. Guidelines for the therapeutic management of SEL are not currently available.

PURPOSE

To elucidate the efficacy of lumbar decompression surgery in SEL.

STUDY DESIGN

Multicenter retrospective study.

PATIENT SAMPLE

A total of 288 consecutive patients who underwent posterior lumbar spinous-splitting decompression surgery for lumbar spinal canal stenosis and followed up greater than 2 years at participating institutions were retrospectively reviewed.

OUTCOME MEASURES

Japanese Orthopedic Association Back Pain Evaluation Questionnaire (JOABPEQ) and Roland-Morris Disability Questionnaire (RDQ).

METHODS

Participants were divided into two groups according to the ratio of EF to anteroposterior diameter of the spinal canal (EF/SC-L) at the spinal level with maximum dural tube compression. Patients with EF/SC-L of ≥0.6 and <0.6 were defined as those with SEL and non-SEL, respectively. We assessed whether surgical treatment was "effective" or "not effective" using the JOABPEQ based on the following: an increase of ≥20 points in the postoperative score compared with the preoperative score, or a preoperative score <90 with a postoperative score ≥90 points. We constructed a multiple Poisson regression model by adjusting for confounding factors, and determined estimated relative risk (RR) for "not effective" with surgical treatment using the JOABPEQ. Additionally, we selected age-, sex-, BMI-, and decompression levels-matched patients with non-SEL and compared the frequency of "not effective" between SEL patients (n=60) and non-SEL patients (n=60).

RESULTS

Analysis using the RDQ and JOABPEQ showed that the 1- and 2-year postoperative scores were significantly better than the preoperative scores in the both groups. Multivariable Poisson regression analysis demonstrated that SEL was significantly associated with "not effective" for decompression surgery in the 1-year postoperative outcomes of walking ability ([RR] 1.5, 95% confidence interval [CI] 1.0-2.2) and social life (RR 1.3, 95% CI 1.0-1.8) and the 2-year postoperative outcomes of walking ability (RR 1.6, 95% CI 1.2-2.3). Matching analysis showed that SEL was significantly associated with "not effective" with lumbar decompression surgery in the 2-year postoperative outcomes of walking ability (p=.02).

CONCLUSIONS

Patients with SEL exhibited significant improvements in surgical outcomes at 1 and 2 years postoperatively. However, compared with the non-SEL group, the efficacy of posterior lumbar spinous-splitting decompression surgery was worse in the SEL group, especially for walking ability. These results indicate that EF accumulation should be considered when planning treatment for patients with lumbar spinal canal stenosis and estimating the efficacy of lumbar decompression surgery.

MRI Diagnosis of Obesity-Related Spinal Epidural Lipomatosis

A 61-year-old male presented to our hospital complaining of claudication: bilateral leg weakness impeding mobility. Symptoms started after 100 m of walk and recede after several minutes of rest. The patient was obese, with a body mass index (BMI) of 41 kg/m2 and reported a weight gain of about 55 pounds in the last year. Patient's comorbidities were dyslipidemia, hypertension, and antithrombin III deficiency. The patient also suffered from chronic low-back pain recently worsened and cervical pain. Pulses in the lower limbs were present. Neurological examination was also unremarkable.

Spinal epidural lipomatosis is associated with liver fat deposition and dysfunction

OBJECTIVE

This study examined the association of spinal epidural lipomatosis (SEL) with liver fat deposition and any other liver dysfunction, except steroid involvement.

PATIENTS AND METHODS

We analyzed 102 patients (62 men and 40 women; mean age 73.3 years) who underwent spinal magnetic resonance imaging (MRI), computed tomography (CT), and myelography for the diagnosis of lumbar spinal canal stenosis between January 2014 and June 2018. Additional data collected included height, weight, body mass index, blood test results (C-reactive protein, albumin, total bilirubin, aspartate aminotransferase, alanine aminotransferase, gamma-glutamyltransferase [γ-GTP], total cholesterol, neutral fat, amylase, urea nitrogen, creatinine, estimated glomerular filtration rate, uric acid, platelets), the epidural fat-occupying ratio in each vertebra from L1/2 to L5/S1 on MRI, and liver CT values.

RESULTS

In 30 cases, the average occupying ratio of epidural fat was ≥40% (SEL), and in 45 cases, liver CT values were <40 HU (fatty liver). Correlation analysis between average occupying ratio of epidural fat and various measurements showed liver CT value (r = -0.574, P <  0.001), body weight (r = 0.304, P =  0.002), γ-GTP (r = 0.370, P =  0.01), and uric acid (r = 0.201, P =  0.04) to be independent explanatory factors. Multivariate analysis revealed that SEL was associated with liver CT value (odds ratio 0.774, 95% confidence interval [CI] 0.689-0.871) and body weight (odds ratio 1.063, 95% CI 1.016-1.135).

CONCLUSION

There was a strong correlation between epidural fat and liver fat deposits suggesting an association between SEL and systemic fat deposition.

Comparison of relative and absolute values of magnetic resonance imaging in the diagnosis of spinal epidural lipomatosis

OBJECTIVE

To describe spinal epidural lipomatosis (SEL) of the lumbar region and evaluate the relative versus absolute values of epidural fat (EF) to determine which is more appropriate when using magnetic resonance imaging (MRI).

DESIGN

Comparative study.

SETTING

Hospital.

PARTICIPANTS

Eight SEL patients and 40 healthy adults.

INTERVENTIONS

MRI measurement of EF.

OUTCOME MEASURES

The MRI-based EF thickness, cutoff value, and coefficient of variation (CV) were calculated. Frequency distribution maps for the absolute EF value and the relative EF/DuS value were created.

RESULTS

SEL involved L3 - L4 in all cases. The mean EF thickness was 12.11 ± 2.28 mm (range: 9.91 - 16.86 mm), and the average diameter of the dural sac (DuS) was 20.02 ± 2.64 mm; the EF/DuS ratio was 0.61 ± 0.03. In controls, the average EF thickness was 7.35 ± 1.68 mm (range: 4.81 - 10.92 mm), and the average DuS was 20.86 ± 2.11 mm; the EF/DuS ratio was 0.35 ± 0.08. The relative and absolute values were significantly higher in the SEL group than in the normal group. A cutoff value of 9.8 mm could distinguish SEL patients from normal individuals. For the SEL group, the CV of the relative values (4.9%) was lower than that of the absolute values (18.8%). The frequency distribution map showed that the distribution of relative values was more concentrated than that of the absolute values for both groups.

CONCLUSION

Based on the frequency distribution and CVs, the relative value of EF/DuS maybe a better measure for diagnosing SEL than the absolute EF value.

Spinal epidural lipomatosis is a previously unrecognized manifestation of metabolic syndrome

BACKGROUND CONTEXT

Spinal epidural lipomatosis (SEL) is a condition in which excess lumbar epidural fat (EF) deposition often leads to compression of the cauda equina or nerve root. Although SEL is often observed in obese adults, no systematic research investigating the potential association between SEL and metabolic syndrome has been conducted.

PURPOSE

To elucidate potential association between SEL and metabolic syndrome.

STUDY DESIGN

An observational study used data of a medical checkup.

PATIENT SAMPLE

We retrospectively reviewed data from consecutive subjects undergoing medical checkups. A total of 324 subjects (174 men and 150 women) were enrolled in this study.

OUTCOME MEASURES

The correlation of EF accumulation with demographic data and metabolic-related factors was evaluated.

METHODS

The degree of EF accumulation was evaluated based on the axial views of lumbar magnetic resonance imaging. Visceral and subcutaneous fat areas were measured at the navel level using abdominal computed tomography. Metabolic syndrome was diagnosed according to the criteria of the Japanese Society of Internal Medicine. The correlation of SEL with metabolic syndrome and metabolic-related conditions was statistically evaluated.

RESULTS

The degree of EF accumulation demonstrated a significant correlation to body mass index, abdominal circumference, and visceral fat area. However, age, body fat percentage, and subcutaneous fat area showed no correlation with the degree of EF accumulation. Logistic regression analysis revealed that metabolic syndrome (odds ratio [OR]=3.8, 95% confidence interval [CI]=1.5-9.6) was significantly associated with SEL. Among the diagnostic criteria for metabolic syndrome, visceral fat area ≥100 cm² (OR=4.8, 95% CI=1.5-15.3) and hypertension (OR=3.5, 95% CI=1.1-11.8) were observed to be independently associated with SEL.

CONCLUSION

This is the first study to demonstrate that metabolic syndrome is associated with SEL in a relatively large, unbiased population. Our data suggest that metabolic-related conditions are potentially related to EF deposition and that SEL could be a previously unrecognized manifestation of metabolic syndrome.

Rapid Development of Spinal Epidural Lipomatosis after Treatment of Metastatic Castration-Resistant Prostate Cancer with Second-Generation Androgen Receptor Antagonists

BACKGROUND

Previous studies have described the association of spinal epidural lipomatosis with several conditions including chronic steroid therapy, Cushing's syndrome, obesity, Paget disease, and hypothyroidism. We present a report of rapid development of spinal epidural lipomatosis after treatment with second-generation anti-androgen therapy, a new strategy for treatment of metastatic castration-resistant prostate cancer that has been increasingly employed in the past few years. A comprehensive discussion of the underlying molecular networks involving androgen receptor blockage and adipocyte differentiation, as well as the clinical implications of such a phenomenon, are provided.

CASE DESCRIPTION

We describe the clinical and radiological evolution of a 58-year-old male patient with metastatic prostate cancer, who developed new onset of rapidly progressing lumbosacral epidural lipomatosis with significant compression of the nerve roots of the cauda equina a few months after initiation of treatment with second-generation androgen receptor antagonists.

CONCLUSIONS

The underlying pathophysiology of adipose tissue growth following the administration of anti-androgen therapy is discussed, with emphasis on both the canonical Wnt/β-catenin pathway as well as in the Wnt-independent pathway involving direct activation of downstream transcription factors from the T-cell factor family by the androgen receptor. As second-generation androgen receptor antagonists have been increasingly used for treatment of castration-resistant stage metastatic prostate cancer, new onset of symptomatic epidural lipomatosis should be considered as a possible differential diagnosis, especially because the urinary symptoms of cauda equina compression may be improperly attributed to the primary prostate neoplasm.

Spinal epidural lipomatosis following bilateral spinal decompression surgery

A 73-year-old man underwent bilateral spinal decompression of L4/5 for severe spinal canal stenosis, requiring minimal analgesia and providing immediate relief. Two days post-operatively, he presented with new onset bilateral leg pain and difficulty mobilising. MRI demonstrated spinal epidural lipomatosis (SEL), which was not present pre-operatively, at L5/S1. Further surgery was performed with decompression of L5/S1 through removal of epidural fat. At both 3 weeks and 5 months follow-up clinics, the patient was asymptomatic. To our knowledge, this is the first case of acute spinal epidural lipomatosis directly following spinal surgery. It is important to recognise SEL as a complication following spinal surgical intervention, due to the potential development of significant neurological consequences.

Volumetric evaluation of lumbar epidural fat distribution in epidural lipomatosis and back pain in patients who are obese: introducing a novel technique (Fat Finder algorithm)

OBJECTIVE

Spinal epidural lipomatosis (EL) represents an excessive deposition of unencapsulated adipose tissue in the spinal canal that can result in chronic back pain in patients who are obese with and without diabetes. We aim to calculate the total volumetric epidural fat on lumbar spine MRI in a predominately obese population and correlate total epidural fat to lower back pain (LBP) and body mass index (BMI).

RESEARCH DESIGN AND METHODS

We developed a program (Fat Finder) to quantify volumetric distribution of epidural fat throughout the lumbar spine. Eleven patients with LBP were imaged using two MRI protocols: parallel axial slices and conventional clinical protocol. The distribution of epidural fat per level was analyzed and normalized to the spinal canal size.

RESULTS

Our sample had an average age of 59.9 years and BMI of 31.57 kg/m². EL subgroup consisted of seven patients. The L2-L5 total fat volume was 3477.6 mm³ (1431.1-5595.9) in the EL group versus 1783.8 mm³ (815.0-2717.5) in the age-similar non-EL group. A higher percentage of fat volume in the canal was associated with higher LBP scores. The fat percentage was 32.2% among patients with EL versus 15.4% for age-similar non-EL with LBP score of 6.1 and 4.0, respectively.

CONCLUSIONS

The Fat Finder is a novel volumetric method to quantify epidural lumbar spinal fat. The epidural fat favors the lower spinal segment with direct proportionality between the fat volume and LBP score, independent of BMI.

The Clinical Characteristics of Spinal Epidural Lipomatosis in the Lumbar Spine

Background

Spinal epidural lipomatosis (SEL) is a rare disease, defined as diffuse hypertrophy of unencapsulated adipose tissue causing spinal canal compression and progressive neurologic deficits. However, there are few studies on SEL in Korea.

Objectives

The purpose of this study was to describe the prevalence and clinical characteristics of SEL in Korea.

Methods

Of the 3702 symptomatic patients (1575 males and 2127 females) who underwent lumbar spine magnetic resonance imaging (MRI) at the age of 20 years or older from January 2014 to December 2016, 42 patients (27 males and 15 females) diagnosed with SEL were selected. Medical records and telephone counseling were used to document sex, age, height, weight, clinical symptoms, coexistent spinal disease, accompanying diseases, and alcoholism and smoking status. One radiologist classified the severity of epidural lipomatosis into three grades from I to III according to Borre et al. We obtained four linear measurements at the axial plane parallel based in the narrowest on MRI image.

Results

The incidence of SEL in the lumbar spine was 1.1%, which was 1.71% in men and 0.7% in women. The mean age was 69.4 ± 10.9 years and the mean body mass index (BMI) was 26.4 ± 3.5 kg/m². The most common clinical symptoms were lower back pain and radiating leg pain (26 patients, 61.9%). The level of affected SEL was found to be most prevalent at L5 - S1 (21 patients, 50%). Concomitant diseases were hypertension (26 patients, 61.9%) and diabetes (12 patients, 28.5%). The most common SEL grade was type III (21 patients, 50%), followed by types II (17 patients, 40.4%) and I (4 patients, 9.5%).

Conclusions

Lumbar spine MRI at one hospital showed that the incidence of symptomatic SEL was 1.1%; SEL is common at the L5-S1 level and in male patients, and severity grade is often severe.

Spinal epidural lipomatosis presenting to a U.S. Veterans Affairs pain and rehabilitation department: a report of two cases

Background

Spinal epidural lipomatosis is an uncommon source of neurogenic claudication. We present two cases of spinal epidural lipomatosis as it relates to diagnosis, management, and a possible association with common medical intervention.

Case presentation

Case 1: 63-year old male patient presented with neurogenic claudication symptoms, but without evidence of bony central canal stenosis on lumbar computed tomography. He entered a trial of spinal manipulation with transient beneficial gains after seven appointments, but no durable change in neurogenic claudication. An MRI was recommended at this point which revealed grade III spinal epidural lipomatosis at the L5/S1 level.Case 2: 51-year old male patient presented to a pain management physician with radicular symptoms for a series of lumbar epidural steroid injections. He completed a series of three lumbar epidural steroid injections with only short-term benefit. A repeat MRI demonstrated the presence of grade I (borderline grade II) spinal epidural lipomatosis.

Conclusions

The first case illustrates a limitation of ruling out central canal stenosis with computed tomography for patients unable to undergo an MRI. The second case demonstrates a possible association between steroid injections and spinal epidural lipomatosis. An association of this kind has not been established; further research is needed to determine the significance.

Idiopathic Spinal Epidural Fat Accumulation Is Associated With Hyperlipidemia

STUDY DESIGN

Single-center retrospective analysis of consecutively collected data.

OBJECTIVE

To determine the clinical characteristics of idiopathic spinal epidural lipomatosis (SEL).

SUMMARY OF BACKGROUND DATA

SEL is associated with the overt accumulation of nonencapsulated adipose tissue in the epidural space, leading to spinal cord or nerve root compression. The etiology of this condition is currently not completely understood.

METHODS

Data of 166 male patients who underwent primary surgery for lumbar spinal canal stenosis (LSS) from May 2013 to February 2016 were retrospectively reviewed. Participants were divided into three groups based on the degree of epidural lipomatous lesion. Patient data of age at surgery, body mass index, prevalence of common noncommunicable diseases, blood tests, arteriosclerotic index, and preoperative clinical scores (assessed using the Japanese Orthopedic Association Back Pain Evaluation Questionnaire) were evaluated. Multivariate analysis was performed to assess the potential associated factors for idiopathic SEL.

RESULTS

Patients with LSS with severe SEL had a significantly higher body mass index and elevated serum levels of total cholesterol and triglyceride compared with those without SEL. Analysis of preoperative clinical scores revealed that patients with SEL experienced pain more frequently and showed less walking ability than did those without SEL. Multivariate analysis revealed that hyperlipidemia was significantly associated with idiopathic SEL (odds ratio = 3.74, 95% confidence interval = 1.31-10.64).

CONCLUSION

Our data suggest that aberrant lipid metabolism is related to the pathogenesis of idiopathic SEL and that patients with LSS with idiopathic SEL have more severe pain than do those without SEL.

LEVEL OF EVIDENCE

3.