Skip Navigation LinksHome > September 2013 - Volume 92 - Issue 9 > Split Cord Malformation
Text sizing:
A
A
A
American Journal of Physical Medicine & Rehabilitation:
doi: 10.1097/PHM.0b013e3182328440
Visual Vignette

Split Cord Malformation

Tsai, Tobias J. MD; Michaud, Linda J. MD, PT

Free Access
Article Outline
Collapse Box

Author Information

From the Department of Physical Medicine and Rehabilitation, Johns Hopkins University School of Medicine, Baltimore, Maryland (TJT); and Division of Pediatric Physical Medicine and Rehabilitation, Departments of Physical Medicine & Rehabilitation and Pediatrics, Cincinnati Children’s Hospital Medical Center, University of Cincinnati College of Medicine, Cincinnati, Ohio (LJM).

All correspondence and requests for reprints should be addressed to: Tobias J. Tsai, MD, Department of Physical Medicine and Rehabilitation, Kennedy Krieger Institute,707 North Broadway, Baltimore, MD 21205.

Financial disclosure statements have been obtained, and no conflicts of interest have been reported by the authors or by any individuals in control of the content of this article. Previously published, in part, as Tsai TJ, Michaud LJ: Split cord malformation in a child with left foot pronation: A case report. PM R 2009;1:S232.

Presented as a poster at the American Academy of Physical Medicine and Rehabilitation 70th Annual Assembly, Austin, Texas, 2009.

A 22-mo-old girl was referred to pediatric rehabilitation clinic for left-foot pronation. Her past medical history was notable for constipation. She had an absent left patellar tendon reflex, and her left plantar response was upgoing. Her gait was notable for left-foot pronation. Brain magnetic resonance image was unremarkable. Lumbosacral spine magnetic resonance image showed splitting of the distal spinal cord into two hemicords with separate central canals, beginning at T12–L1 (Fig. 1). The hemicords reunited at L3. There was tethering of the cord with the conus terminating in a lipoma extending from L5 through S5.

FIGURE 1
FIGURE 1
Image Tools

The term split cord malformation (SCM) was proposed by Pang et al.1 as common nomenclature for the double spinal cord conditions historically known as diastematomyelia and diplomyelia. Diastematomyelia is most frequently referred to as a condition in which two hemicords, each with its own central canal and pia mater, inhabit their own dural tube and are separated by a dural-sheathed rigid, bony median septum. Diplomyelia is referred to as a condition in which two hemicords share a single dural tube but are separated by a nonrigid fibrous septum. Both conditions may share the same embryogenetic mechanism.1 Early in development, adhesions between ectoderm and endoderm can form an endomesenchymal tract that splits the notochord, forming two hemineural plates and hemineural tubes. Mesoderm may then associate with the endomesenchymal tract. If the mesoderm surrounds each hemineural tube, the formation of a bony septum and the condition now known as SCM type I occurs. Otherwise, a single dural sac develops, and the remains of the endomesenchymal tract create a nonrigid fibrous septum and the condition now known as SCM type II. Both conditions are associated with spinal cord tethering and have clinical implications. This patient does not have a bony septum and was given a diagnosis of SCM type II.

This patient’s most striking abnormality on examination was unilateral foot pronation. Unilateral findings in conjunction with combined upper- and lower-motor neuron signs have often been reported in SCM, including eight patients with left–right functional discrepancy in the seminal paper published by Pang.2 Treatment is surgical and may include detethering and/or resection of a fibro-osseus septum. This patient’s constipation resolved after detethering, and her gait has been stable postoperatively. In retrospect, her constipation was likely caused by a neurogenic bowel. Split cord malformation should be considered in the differential diagnosis of patients with suspected tethering lesions for whom early detection may allow preservation of function.

Back to Top | Article Outline

ACKNOWLEDGMENTS

We thank William S. Ball, MD, for interpretation of the MRI.

Back to Top | Article Outline

REFERENCES

1. Pang D, Dias MS, Ahab-Barmada M.: Split cord malformation: Part I: A unified theory of embryogenesis for double spinal cord malformations. Neurosurgery. 1992; 31: 451–80

2. Pang D.: Split cord malformation: Part II: Clinical syndrome. Neurosurgery. 1992; 31: 481–500

Copyright © 2011 by Lippincott Williams & Wilkins

Login

Article Tools

Images

Share