Pathological changes and surgical treatment of lipomas of the conus medullaris.

Objective: To describe the pathological changes of lipomas of the conus medullaris and the appropriate surgical treatment for removing such lipomas for optimal reconstruction of the normal spinal cord anatomy.

Methods: Data were collected on 73 patients, aged 1.5 months to 18 years, who underwent surgical removal of a lipoma of the conus medullaris at Shanghai Children's Medical Center from January 2005 to December 2008. Neurological symptoms included pain, urine and stool incontinence, and bilateral lower limb dysfunction. The surgical procedures consisted of excision of subcutaneous and intradural extramedullary lipoma, partial excision of intramedullary lipoma, detachment of the spinal cord from the dural membrane, relief of tethered spinal cord, and excision of the affected filum terminale.

Results: The main pathological changes in patients with lipoma of the conus medullaris were ventral deviation of the spinal cord caused by compression from a dorsal lipoma, traction on the spinal cord from attachment of intradural lipoma and subcutaneous lipoma, increased tight fit between the spinal cord and the dural membrane on both sides, and degeneration of the filum terminale. A total of 67 patients were followed up for 6 months to 4 years. Improvement after surgery varied among the symptomatic patients. A total of 5 patients had transient deterioration of symptoms after surgery. All asymptomatic patients remained asymptomatic.

Conclusion: Only through thorough understanding of the pathology of the lipoma of the conus medullaris, we could optimally excise the lipoma, untether the spinal cord, reconstruct the normal anatomy of the spinal cord, and rehabilitate neurological function.