Imaging in clinical medicine: traumatic pseudomeningocoele.

An 18-year-old male was involved in a road traffic accident that led to a fracture of the left clavicle. He was put in a brace. Over a month, the patient noted tingling, numbness, and difficulty in moving his left upper limb. Clinical examination showed severe motor weakness in the left upper limb. A traumatic brachial plexopathy was suspected. Nerve conduction studies and electromyography showed a complete brachial plexopathy affecting C5-D1 fibers with complete axon degeneration. A cervical magnetic resonance imaging (MRI) showed paraspinal cystic lesions at the level of C7-D1 and D1-D2 neural foramen consistent with traumatic pseudomeningocoeles (Figs. 1, 2, 3 and 4). No spinal cord injury was found.

Fig. 1

Coronal T2 weighted image showing a well-defined cystic structure (arrow) in the left paraspinal location at C7-D1 level.

Fig. 2

Coronal T2 weighted image showing similar morphology lesion (arrow) at an inferior level of D1-D2 neural foramen.

Fig. 3

Axial T2 weighted image showing the intra as well extra spinal location of the lesion (arrow).

Fig. 4

Axial gradient echo image showing the lesion (arrow) as being completely cystic.

Pseudomeningocoeles are formed due to leakage of cerebrospinal fluid through a defect in the overlying meninges. The leaked CSF collects in the adjacent soft tissues and forms a fibrous pseudomembrane over a period of time (1). Traumatic pseudomeningocoeles typically occur after a severe traction injury. Although there is a strong association between nerve root avulsion and pseudomeningocoeles, a significant percentage of avulsions do not show any pseudomeningocoeles and pseudomeningocoeles can occur without any nerve root avulsion (2). Traumatic pseudomeningocoeles should be differentiated from other dumb-bell shaped lesion occurring in the paraspinal location including synovial cysts, paraspinal abscesses, neural sheath tumors, and other benign and malignant lesions. An MRI is the modality of choice for evaluating brachial plexus injuries because of its excellent soft tissue contrast and multiplanar capability.