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

Follow-Up Study

Careful follow up of patients who underwent resection of a lipomyelomeningocele is important because of the risk of delayed neurological deterioration from retethering. After a series of acutecare postoperative visits at 1, 3, and 6 months, these patients typically attend annual follow- up visits until they reach adulthood. Occasionally when a family appears particularly attentive and well informed such that our concern of missing signs of neurological decline is reduced, we will see these patients once every 2 years. The most important component to follow up is the patient's clinical history. Whereas some authors support the undertaking of urodynamic studies in following these patients, we have not found this to be a useful adjunct. Our decision to conduct surgical reexploration instead of simply following these patients is based on recurrence of pain or evidence of neurological decline. An imaging study is typically only obtained once a decision to operate has already been made on clinical grounds.

Rarely growth of spinal lipomas may be found on sequential imaging studies, and lipomas have occasionally recurred after resection. Lipomas will typically enlarge with age in proportion to body growth so that significant weight gain, particularly if associated with obesity, may contribute to recurrence of spinal lipomas. Malignant transformation is exceedingly rare.

Intradural Spinal Lipomas

Lipomas of the spinal cord are considered to behave as spinal cord tumors that cause neurological deficit as a result of their mass effect.[43] Perhaps best considered as congenital inclusion tumors of the central nervous system, they represent approximately 1% of all spinal cord tumors.[24] These lesions are intradural and vary with regard to their relationship to the spinal cord.[37] Some are completely intramedullary whereas others are part intramedullary and part extramedullary.[53] They are typically thoracic in location, although the cervical region is most common in children.[25,34,71,76] Lipomas of the spinal cord typically present in the second and third decade of life. Lee, et al.,[39] have described a series of six patients harboring these lesions who typically presented with long histories of disability followed by rapid progression of symptoms, and most patients were in poor neurological condition on presentation. The presenting symptoms included spinal pain, dysesthetic sensory changes, gait difficulties, weakness, and incontinence.

Surgical management is aimed at elimination of mass effect. The relationship of the lipoma to the spinal cord is the critical determinant of the of resection that may be obtained. Because these lesions are very slow growing and cause neurological insult secondary to mass effect, a very satisfactory and long-lasting clinical effect may be obtained after achieving a subtotal excision.

Surgical Approach

With the patient in the prone position a midline incision is made. Because the skin and soft tissues typically appear to be normal, localization can be challenging. It is often useful to place a vitamin E capsule on the skin at the time the MR imaging is performed to allow skin marking for incision planning. Alternately intraoperative preincision plain x-ray films may be obtained and compared with pre-operative images position the incision to optimally. Once the incision is made, a midline approach and subperiosteal dissection is pursued. The number of laminae removed depends on the size of the underlying lesion.

Once the laminectomy has been performed, intraoperative ultrasonography can be very useful in confirming proper localization before the dura is opened; additionally, this modality can be helpful in deciding whether more laminae need to be removed. Dural opening and retention sutures then are placed, and the lipoma is inspected under the operating microscope. A combination of CO 2 laser and/or ultrasonic aspiration is used to reduce the mass of the lesion to the maximum extent that is safe. Intraoperative monitoring may be very useful, particularly if cord retraction or rotation is anticipated for optimum exposure of the lesion. Once maximal mass effect is relieved a thorough layer-by-layer closure ensues to minimize the likelihood of CSF leaks.

Abbreviations used in this paper: CSF = cerebrospinal fluid; MR = magnetic resonance; OSD = occult spinal dysraphism; TCS = tethered cord syndrome.

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