Spinal Lipomas

Jeffrey P. Blount, MD, and Scott Elton, MD, Division of Neurosurgery, University of Alabama at Birmingham, Children's Hospital of Alabama, Birmingham, Alabama

Neurosurg Focus. 2001;10(1) 

In This Article

Neurodiagnostic Imaging

After OSD is suspected on clinical grounds the first logical step is to obtain appropriate neuroimaging studies to define the anatomical and pathological features of the lesion. Ultrasonography is a useful modality in the radiological evaluation of an infant suspected of harboring a lipomyelomeningocele. Lipomatous tissue is highly echogenic and as such can be readily defined on an ultrasound. A combination of plain x-ray films and MR images most precisely and efficiently defines lipomas of the spine in older children and adults. Computerized tomography scanning may be reserved for cases in which additional bone abnormalities are suspected based on clinical or radiological findings (for example, diastomyelia or split cord malformation). Computerized tomography myelography provides excellent resolution of the anomaly; however, this modality is invasive, requires exposure to radiation and requires lumbar puncture which can be a particularly hazardous undertaking in the setting of a low-lying conus.[13,62]

Plain x-ray films almost uniformly demonstrate abnormal findings. The most common findings include dorsal midline fusion defects (spina bifida) and a widened spinal canal. In young children (18 months of age) incomplete calcification of bone elements limits the practical utility of conducting plain radiography.[26]

Magnetic resonance imaging has evolved to become the imaging modality of choice for dysraphic states.[9] Lipomatous tissue demonstrates high signal on T 1 -weighted MR images and low signal on T 2 -weighted MR images (Figure 3). Contrast material administration is not necessary. Precise definition of the relationship of normal and pathological structures combined with the ability to obtain images in three dimensions allows the surgeon to plan an operative approach in which understanding of the lesion is optimal.[9,26,43]

Figure 3

Magnetic resonance imaging studies. Left: Axial T 1 -weighted image sequence without contrast, demonstrating fat of lipoma applied to the dorsal surface of dorsally displaced spinal cord. Center: Sagittal T 1 -weighted image of the lumbar spine without contrast, revealing caudal lipomyelomeningocele extending out of spinal canal, through a defect in bony lamina, and into the subcutaneous space. Right: Sagittal T 1 -weighted image revealing a caudal lipomyelomeningocele with low-lying conus (L3-4) and terminal syringomyelia.

The greatest drawback to MR imaging is its ineffectiveness postoperatively. Characteristically the area in which the lipomyelomeningocele has been resected and the cord untethered demonstrates a diffuse area of abnormality where tissue planes are disrupted; the conus medullaris remains low; and the resulting scar tissue melds homogeneously with residual fibrofatty tissue of the lipoma. Magnetic resonance imaging does not provide meaningful information with regard to the success of an untethering operation nor can it establish retethering.[7]

Comments

3090D553-9492-4563-8681-AD288FA52ACE
Comments on Medscape are moderated and should be professional in tone and on topic. You must declare any conflicts of interest related to your comments and responses. Please see our Commenting Guide for further information. We reserve the right to remove posts at our sole discretion.

processing....