gms | German Medical Science

Objective: Spinal pseudomeningoceles (SPM) are extradural collections of CSF that may develop after traumatic injury; a frequent association with upper cervical injuries (UCI) has been observed. We propose a possible etiopathogenetic mechanism supporting the formation of cervical SPM based on some considerations.

Methods: We present four cases of SPM. All patients had suffered a severe UCI with 3 cases of occipital condyle fracture and 1 case of atlanto-axial dislocation. Three patients were symptomatic with delayed and progressive clinical signs.

Results: One patient was misinterpreted as cervical epidural hematoma and operated on due to progressive signs with postoperative clinical improvement. The remaining patients were treated conservatively, and a spontaneous reduction of the CSF collection occurred. Analysis of radiological patterns showed the following: 1) a line of demarcation clearly separated the intradural cervical compartment from the anterior epidural space, validating the definition and occurrence of SPM; 2) CSF epidural collection was never evident at C0-C2 level and extended from C2 downwards; 3) the shape of the fluid collection was similar to epidural hematomas with a flute beak upper extremity whose tip pointed to the inferior aspect of C2 suggesting firs of all that a ball-valve mechanism controls the formation and development of SPM, and secondly that the collection is likely to be generated from C0-C2 downwards.

Conclusions: The dura extending from C0 to C2 levels appears to be adherent to the thick ligamentous apparatus and reinforced by multiple layers of connective tissue, as opposed to the segments below where it is solely covered by the posterior longitudinal ligament. We think that a “transitional zone” of dura exists between the C0-C2 region and subaxial segment of the cervical spine. This watershed area constitutes a point of minor resistance due to the coexistence of two opponent forces: the elastic force of the subaxial dura and the stiff component of UC connective tissue apparatus. Distraction of the C0-C2 complex due to a severe UCI may be responsible for lacerations of the meningeal layers at the “transitional zone” with subsequent draining of CSF into the epidural space.