No abstract

We describe a patient with traumatic right-sided invagination of two consecutive laminae into the spinal canal. The injury resembled a greenstick fracture and resulted in an acute Brown-Sequard syndrome. There was also an undisplaced hangman's fracture of the axis vertebra. These injuries were caused by an acute hyperextension and axial compression of the cervical spine. Open reduction and internal fixation of the laminar fractures without fusion was followed by full neurological recovery within six weeks.

We describe a patient with traumatic right-sided invagination of two consecutive laminae into the spinal canal. The injury resembled a greenstick fracture and resulted in an acute Brown-Séquard syndrome. There was also an undisplaced hangman's fracture of the axis vertebra. These injuries were caused by an acute hyperextension and axial compression of the cervical spine. Open reduction and internal fixation of the laminar fractures without fusion was followed by full neurological recovery within six weeks.J Bone Joint Surg [Br] 2000;82-B:1148-50. Received I October 1999 Accepted 22 December 1999 Case reportAn 18-year-old man was involved in a head-on vehicle collision. Sitting unrestrained in the passenger seat, he hit the dashboard with his forehead and felt a sudden electric pain shooting down his right side while his head was forced backwards. He was immediately aware of right-sided weakness, more pronounced in the upper limb than in the lower. Clinical examination revealed mild neck pain, right-sided hemiparesis from C5 downwards and patchy paraesthesiae on the left side, more pronounced in the lower limb but right-sided weakness was more obvious in the upper. Plain lateral radiography revealed an undisplaced 'hangman's' fracture of the C2 lamina and a barely discernible step in the spinolaminar line from C4 to C5 (Fig. 1a). The anteroposterior (AP) radiograph showed a shift of the fourth and fifth cervical spinous processes to the right (Fig. 1b). CT demonstrated an undisplaced asymmetrical hangman's fracture ( Fig. 2a) and invagination of the right hemilaminae of the fourth and fifth cervical vertebrae with a shift of the spinous processes towards the right side (Figs 2b and 2c). The injury to the laminae resulted in partial reduction in the volume of the spinal canal on the right side. The midline AP diameter of the spinal canal was reduced from 10.5 mm to 7 mm at the level of the C5 vertebra. The patient was initially treated by skeletal traction (3 kg) applied using Crutchfield tongs. As the neurological deficit did not recover during the following week operation was undertaken.Through a posterior approach, exposing the laminae and lateral masses from C3 to C6, the invagination of the right laminae of the C4 and the C5 vertebrae was confirmed. All other posterior elements such as the facet joints, ligamentum flavum, interspinous ligaments and spinous processes were intact. The fracture at C2 was not exposed. Reduction of the invaginated laminae was achieved by gentle traction on the spinous processes. Mild flexion of the neck helped to maintain the reduction. As the neck was extended there was a tendency for the laminae to reinvaginate. Transverse wiring of the two involved spinous processes was undertaken with tension towards the left-sided lateral masses to maintain the position of the reduced laminae.Adequate decompression was confirmed on a postoperative CT scan (Figs 3a and 3b). Skeletal traction was continued. The left-sided paraesthesiae, and the motor impairment of the right lower limb recov...