Morphometric multislice computed tomography examination of the craniovertebral junction in neck flexion and extension.

BACKGROUND: Detailed study of the craniovertebral junction (CVJ) is necessary to completely understand the mechanism of its flexion and extension. MATERIALS AND METHODS: One cadaver head was sectioned in the sagittal plane. Also, in 22 volunteers, examined using the multislice computed tomography (MSCT), 14 parameters and 2 angles were measured in the neutral position, flexion and extension. RESULTS: The obtained measurements showed the anterior part of the occiput to move inferiorly in flexion, and the anterior atlas arch and the tip of the dens to get closer to the basion. At the same time, the opisthion moves superiorly, but the cervical spine bends anteriorly. Consequently, the dens-opisthion diameter and the opisthion-posterior atlas arch distance slightly decrease in length, whilst the arches of the atlas (C1), axis (C2) and C3 vertebra become more distant. Following extension, the posterior part of the occiput moves inferiorly, so that the basion-dens tip, the basion-axis arch, and the basion-posterior atlas arch distances increase in length. In contrast, the distances of the C1-C3 arches decrease in length. The angle between the foramen magnum and the dens tip decreases 1.620 on average in flexion, but increases 3.230 on average in extension. The angle between the axis body and the opisthion also decreases in flexion (mean, 3.360) and increases in extension (mean, 6.570). Among the congenital anomalies, a partial agenesis of the posterior atlas arch was revealed (4.5%), as well as an anterior dehiscence of the C1 foramen transversarium (13.6%). CONCLUSIONS: The mentioned measurements improved our understanding of the CVJ biomechanics. The obtained data can be useful in the evaluation of the CVJ instability caused by trauma, congenital anomalies and certain spine diseases.

Craniovertebral anomalies associated with pituitary gland duplication.

BACKGROUND: An extremely rare occurrence of the pituitary gland duplication inspired us to examine in detail the accompanying craniovertebral congenital anomalies in a patient involved. MATERIALS AND METHODS: T1-wighted magnetic resonance imaging (MRI) was performed, as well as the multislice computerised tomography (MSCT) and MSCT angiography in our patient, as well as in a control group of 10 healthy subjects. RESULTS: In a 20-year-old male a double pituitary gland was identified, as well as hypothalamic enlargement, tuberomamillary fusion and hamartoma. In addition, the patient also showed a duplicated hypophyseal fossa and posterior clinoid processes, notch of the upper sphenoid, prominent inner relief of the skull, inverse shape of the foramen magnum, third occipital condyle, partial aplasia of the anterior and posterior arches of the atlas with a left arcuate foramen, duplication of the odontoid process and the C2 body, and fusion of the C2-C4 and T12-L1 vertebrae. The MSCT angiography presented a segmental dilatation of both vertebral arteries and the A2 segment of the anterior cerebral artery, as well as a duplication of the basilar artery. CONCLUSIONS: This patient is unique due to complex craniovertebral congenital anomalies associated with a duplication of the pituitary gland.

Surgical prevention of paralytic dislocation of the hip in cerebral palsy.

Paralytic dislocation of the hip in cerebral palsy may be prevented by soft tissue surgery and the results of two procedures are reported. Twenty hips were treated by adductor tenotomy alone and this was unsuccessful in every case. An alternative method was carried out in 42 hips in 25 patients. The procedure combined adductor tenotomy with release of the hip muscles including iliac crest resection, tenotomy of the rectus femoris, recession of the iliopsoas and, when necessary, either release or transposition of the knee flexors. This was much more successful in decreasing migration of the femoral head.