[Instability and misdiagnosed or neglected dislocations of the upper cervical spine in children. Apropos of 20 cases]

Abstract

Neglected instabilities or luxations of the upper cervical spine in children are rare if one discards conditions such as chondrodysplasia, Down Syndrome or others, were the spine is known to be at high risk of instability. We have studied twenty cases of neglected luxations and the delay in diagnosis is explained either by the asymptomatic character of some of these lesions, or by the difficulty in diagnosis. At the occipito-atlantal level we have reviewed: an instability in translation which required an occipito-axial fusion; two compensatory counter occipito-atlantal luxation of an atlanto-axial rotatory fixation. The diagnosis was best made with computed tomography scan and the treatment was not much different from the isolated atlanto-axial rotatory luxation. An instability in flexion extension, which was merely followed at regular intervals. At the atlanto-axial level 9 cases of sagittal instabilities in kyphosis and translation with a distance between atlas and axis of more than 5 mm were observed. These instabilities were most often associated with a malformation of the cranio-cervical junction; their treatment was usually surgical by means of an atlanto-axial or occipito-axial arthrodesis depending on the case. 9 other cases of atlanto-axial rotatory luxations were either isolated (7 cases) or associated with a counter occipito-atlantal rotatory subluxation (2 cases). Their diagnosis was made on routine X-rays, but the complete or incomplete aspect of the luxation, as well as its fixed aspect, was best appreciated with dynamic CT scan. Their treatment was always started with collar neck or halo traction in order to obtain, reduction of the dislocation, or at least the disparition of the torticollis and the head straight up on shoulders. The stability of the spine was achieved with a minerva cast jacket, halo cast or spine fusion depending on the case.