Fractures of the arch of the lower cervical spine.

In a series of 285 cases of injuries of the lower cervical spine, fractures of the vertebral arch constituted 12.6%. 27 cases treated conservatively were analysed in view of their subtyping and clinical properties and with reference to the choice of treatment. Five different main subtypes of fractures of the vertebral arch of the lower cervical spine can be distinguished: 1) Bilateral fracture of lamina, without displacement of the vertebra or with subluxation. The assessment of potential instability is discussed, and criteria for its evaluation are presented; 2) Bilateral fracture of lamina combined with locked luxation, which is difficult to reduce by conservative means; 3) Detachment of the articular mass, which invariably causes instability, which, however, is usually relative because of the preserved posterior ligamentary complex. Conservative treatment is seldom able to produce a reduced position, but the only associated drawback is the theoretical possibility of continuous or intermittent compression of the injured spinal cord; 4) Bilateral pedicular fracture which is rare; 5) Combined fractures of the arch, which are highly unstable. The frequency of neurological complications necessitating skull traction is high in association with fractures of vertebral arches of the lower cervical spine. However, some bilateral fractures of lamina and detachments of the articular mass can be treated satisfactorily with an orthopaedic brace or a plaster collar. Indications for operative treatment are present in a few cases only, the main indication being early mobilizaiton.