[MIM 222 500]

(diplomyelia)

Rare. Spinal dysraphism characterized by the presence of a median fibrous or bony spur passing through the spinal canal in the sagittal plane. It is part of the split cord malformations group. The term is coined from the Greek: diastema, slot, and myelos, marrow). 

There are two distinct types:

-         type I: (diastematomyelia) both medullary cords have their own dura mater and are separated by a rigid septum covered by the dura mater.

The CanazeSarica classification:

Ia: the bony spur is ventral and linked to the posterior part of the vertebrae by a cartilaginous bridge

Ib: the bony spur is dorsal and linked to the anterior part of the vertebrae by a cartilaginous bridge

Ic:  the bony spur is central and linked to the vertebrae by a cartilaginous bridge

-         type II: both medullary cords are surrounded by the same dura  mater and are separated by a non-rigid fibrous septum

This malformation is generally occult as it is covered with skin. It can be diagnosed late on the occasion of the development of early scoliosis or pain. The skin next to the lesion is often abnormal: tufts of hairs, dorsal lipoma, port-wine stain...

Often associated with other spinal malformations: hemivertebrae, tethered cord, lipomeningocele, neurenteric cyst, Chiari type II malformation (see this term). It is sometimes associated with a Klippel-Feil syndrome (see this term).

Anesthetic implications: 

keep it in mind in case of early scoliosis or in case of a skin abnormality next to the spinal axis. Preoperative MRI of the neuraxis and the brain. In case of corrective surgery: management as for a scoliosis repair, risk of post-operative leak of CSF.

References : 

-         Ersahin Y, Mutluer S, Kocaman S, Dermitas E. 
Split spinal cord malformations in children. 
J Neurosurg 1998; 88: 57-65.

-         Soundararajan N, Cunliffe M. 
Anaesthesia for spinal surgery in children. 
Br J Anaesth 2007; 99: 86-94.

-         Hannebicque-Montaigne K, Chaffiotte C, Joriot S, Vinchon M, Deruelle P.
Diastématomyélie : difficultés du diagnostic anténatal. 
Rev Méd Périnat 2010 ; 2 : 223-6.

-        Dubey PK, Kant S. 
Split cord malformation and the anaesthesiologist. 
Indian J Anaesth 2014; 58: 354-5.

-        Sack AM, Khan TW.
Diastematomyelia: split cord malformation.
Anesthesiology 2016; 125:397

-        Wenger M, Hauswirth CB, Brodhage RP.
Undiagnosed adult diastematomyelia associated with neurological symptoms following spinal anaesthesia.
Anaesthesia. 2001;56:764–7.

-        Pak A, Abrahams E.
Epidural placement in a patient with a type 2 split cord malformation in the interventional pain management setting: a case report.
A&A Practice 2021 ; 15 : e15013.

Updated: October 2021