Spinal epidural lipomatosis is a condition involving an abnormal buildup of fat tissue within the spinal canal’s epidural space. This region surrounds the dural sac that encases the spinal cord and nerve roots. The excess, unencapsulated adipose tissue can narrow the spinal canal, compressing these neural structures. While a rare disorder, it is a recognized cause of back pain and neurological symptoms that develop gradually.
Associated Conditions and Causes
The development of spinal epidural lipomatosis is linked to circumstances that alter the body’s fat distribution. The most common trigger is the long-term use of exogenous corticosteroids, such as prednisone, prescribed for inflammatory and autoimmune conditions. Steroids are believed to stimulate glucocorticoid receptors in fat tissue, promoting its expansion within the epidural space.
The condition can also arise from internal factors that increase cortisol levels, such as Cushing’s syndrome, an endocrine disorder characterized by the overproduction of cortisol. Obesity is another significant risk factor, as excess body weight can contribute to the hypertrophy of epidural fat. In a smaller subset of cases, the cause cannot be identified, and it is classified as idiopathic.
Recognizing the Symptoms
Symptoms of spinal epidural lipomatosis emerge as growing fat deposits press on the spinal cord and nerve roots. A common initial complaint is gradually worsening lower back pain, often with stiffness and a limited range of motion. The symptoms’ location corresponds to the area of fat accumulation, most often the thoracic and lumbar regions.
When excess fat compresses individual nerve roots, radiculopathy can develop. This manifests as pain that radiates from the back into the limbs, numbness, tingling, or muscle weakness in the legs, similar to sciatica.
A more serious set of symptoms, myelopathy, occurs if the fat compresses the spinal cord itself. This can lead to difficulties with walking and balance, loss of coordination, and weakness in the lower extremities. In advanced cases, compression can interfere with nerves controlling the bladder and bowels, leading to incontinence, which requires prompt medical evaluation.
The Diagnostic Process
Confirming a diagnosis relies on advanced imaging, with Magnetic Resonance Imaging (MRI) being the most effective tool. An MRI provides clear, detailed images of the spinal cord, nerve roots, and the surrounding epidural fat without using radiation. A radiologist looks for a characteristic overgrowth of adipose tissue, which produces a bright white signal on specific MRI sequences.
This allows a physician to see the precise location of the fat and assess the degree of compression. While Computed Tomography (CT) scans can be used, they are less definitive as they provide less contrast of soft tissues compared to an MRI. For this reason, MRI remains the standard for accurately diagnosing the condition.
Management and Treatment Approaches
The treatment strategy is guided by the underlying cause and the severity of neurological symptoms. A conservative, non-surgical approach is the first line of defense. If long-term corticosteroid use is the cause, a physician will supervise a gradual tapering of the medication. For individuals where obesity is the main factor, a structured weight loss program involving diet and exercise is recommended. If an endocrine disorder like Cushing’s syndrome is diagnosed, managing that condition becomes the priority.
Surgical intervention is reserved for cases where conservative management fails or when there are severe and progressive neurological deficits, such as profound weakness or loss of bladder control. The most common procedure is a decompressive laminectomy, where a surgeon removes a portion of the vertebral bone (the lamina) to create space and remove the excess epidural fat, a process known as debulking.