Spinal Lipomas
Lipomas of the spinal cord are among the most fascinating lesions encountered by the pediatric neurosurgeon. An understanding of spinal lipomas may, however, be difficult because the terminology used to describe the accumulations of spinal fat is confusing, inconsistently applied, and at times contradictory. An anatomical characterization of lipomas may assist in understanding these lesions. Lipomas of the spinal cord are very rare and cause symptoms related to mass effect and secondary compressive myelopathy. Lipomas of the conus medullaris (or lipomyelomeningocele) are the most common form of fatty masses in the spine and can be divided into dorsal, caudal, and transitional forms. These lesions are a manifestation of occult spinal dysraphism and a common cause of the tethered cord syndrome (TCS). The natural history of untreated lipomyelomeningocele, although incompletely understood, appears to be progressive neurological deterioration with loss of bladder control. Timely, careful surgical intervention may prevent significant neurological deterioration and progressive disability in the majority of children harboring these lesions. In surgical intervention the surgeon seeks to disrupt the connection between the fibrofatty mass and underlying cord as well as to reestablish normal anatomical planes. Several intraoperative video segments illustrating lipomyelomeningocele resection are included in this paper. Lipomas of the terminal filum (fatty filum) are truly occult and are also associated with TCS. Surgical treatment of filum lipomas carries significantly lower risk than that for lipomas of the conus medullaris. Again, the goal of surgery is to disrupt the connection between the abnormal fibrofatty tissue and the underlying spinal cord.
Lipomas of the spinal cord are among the most fascinating lesions encountered frequently by the pediatric neurosurgeon. Timely, careful surgical intervention may prevent the development of significant neurological deterioration and progressive disability in the majority of children harboring these lesions. As such, spinal lipomas can be among the most rewarding of congenital lesions to treat. An understanding of spinal lipomas may, however, be difficult because the terminology used to describe the accumulations of spinal fat is confusing, inconsistently applied, and at times contradictory. The terms lipoma, lipomyelomeningocele, and lipomeningocele are used by different authors to describe the same or similar conditions. The term lipomyelomeningocele is misleading in that there is no anomaly of the overlying skin. The suffix "oma" implies a neoplastic event in the pathophysiology of the lesion; however, the majority of spinal lipomas arise from a disorder of embryogenesis and reflect a form of OSD. Furthermore, such lipomas do not consist of a single cell type but rather demonstrate fibrous tissue, muscle cells, neural tissue, and a variety of other cell types that arise from all three embryonic layers. Whether such disordered embryogenesis gives rise to a truly teratomatous fatty neoplasm is controversial. Other less common spinal lipomas are true benign fatty neoplasms of adipocytes that may become symptomatic by virtue of their mass. To make matters more confusing, various disorders that differ in their pathophysiology and natural history result in fat accumulation within the spine.
Abstract and Introduction
Abstract
Lipomas of the spinal cord are among the most fascinating lesions encountered by the pediatric neurosurgeon. An understanding of spinal lipomas may, however, be difficult because the terminology used to describe the accumulations of spinal fat is confusing, inconsistently applied, and at times contradictory. An anatomical characterization of lipomas may assist in understanding these lesions. Lipomas of the spinal cord are very rare and cause symptoms related to mass effect and secondary compressive myelopathy. Lipomas of the conus medullaris (or lipomyelomeningocele) are the most common form of fatty masses in the spine and can be divided into dorsal, caudal, and transitional forms. These lesions are a manifestation of occult spinal dysraphism and a common cause of the tethered cord syndrome (TCS). The natural history of untreated lipomyelomeningocele, although incompletely understood, appears to be progressive neurological deterioration with loss of bladder control. Timely, careful surgical intervention may prevent significant neurological deterioration and progressive disability in the majority of children harboring these lesions. In surgical intervention the surgeon seeks to disrupt the connection between the fibrofatty mass and underlying cord as well as to reestablish normal anatomical planes. Several intraoperative video segments illustrating lipomyelomeningocele resection are included in this paper. Lipomas of the terminal filum (fatty filum) are truly occult and are also associated with TCS. Surgical treatment of filum lipomas carries significantly lower risk than that for lipomas of the conus medullaris. Again, the goal of surgery is to disrupt the connection between the abnormal fibrofatty tissue and the underlying spinal cord.
Introduction
Lipomas of the spinal cord are among the most fascinating lesions encountered frequently by the pediatric neurosurgeon. Timely, careful surgical intervention may prevent the development of significant neurological deterioration and progressive disability in the majority of children harboring these lesions. As such, spinal lipomas can be among the most rewarding of congenital lesions to treat. An understanding of spinal lipomas may, however, be difficult because the terminology used to describe the accumulations of spinal fat is confusing, inconsistently applied, and at times contradictory. The terms lipoma, lipomyelomeningocele, and lipomeningocele are used by different authors to describe the same or similar conditions. The term lipomyelomeningocele is misleading in that there is no anomaly of the overlying skin. The suffix "oma" implies a neoplastic event in the pathophysiology of the lesion; however, the majority of spinal lipomas arise from a disorder of embryogenesis and reflect a form of OSD. Furthermore, such lipomas do not consist of a single cell type but rather demonstrate fibrous tissue, muscle cells, neural tissue, and a variety of other cell types that arise from all three embryonic layers. Whether such disordered embryogenesis gives rise to a truly teratomatous fatty neoplasm is controversial. Other less common spinal lipomas are true benign fatty neoplasms of adipocytes that may become symptomatic by virtue of their mass. To make matters more confusing, various disorders that differ in their pathophysiology and natural history result in fat accumulation within the spine.
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