Saccular limited dorsal myeloschisis

Saccular limited dorsal myeloschisis is a rare congenital spinal dysraphism classified as a form of limited dorsal myeloschisis (LDM). In this condition, there is a focal defect in the dorsal midline of the spinal cord where a stalk of abnormal tissue (the myeloschisis stalk) connects the spinal cord to the skin surface, and the overlying skin forms a visible sac-like (saccular) outpouching on the back. Unlike open neural tube defects such as myelomeningocele, the neural tissue in limited dorsal myeloschisis remains covered by skin, making it a form of closed spinal dysraphism. The saccular variant is distinguished from the flat variant of LDM by the presence of this prominent skin-covered sac, which can sometimes be mistaken for a meningocele or lipomyelomeningocele. The condition primarily affects the central nervous system, specifically the spinal cord and its surrounding structures. Key clinical features may include a visible midline dorsal skin lesion (the sac), and patients may present with or develop neurological symptoms including lower limb weakness, sensory changes, bowel and bladder dysfunction, and orthopedic deformities of the feet or spine, particularly as they grow. Tethering of the spinal cord by the myeloschisis stalk is a major concern, as progressive tethered cord syndrome can lead to worsening neurological deficits over time. Some patients may be neurologically intact at birth, with symptoms developing later in childhood. Treatment is primarily surgical and involves untethering of the spinal cord by excising the fibroneural stalk that connects the cord to the skin, along with removal of the saccular component. Early surgical intervention is generally recommended to prevent progressive neurological deterioration from cord tethering. Outcomes depend on the degree of neurological involvement at the time of diagnosis and the success of surgical untethering. Long-term follow-up is important to monitor for re-tethering and progressive neurological changes.

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