Biomechanics and classification of traumatic lesions of the spine

The neurological characteristic of patients with fractures of thoracolumbar junction presenting in Timisoara County Clinical Emergency Hospital's Emergency Unit

OBJECTIVE

The current study aims to find the neurological characteristic of thoracolumbar junction fractures as well as the impact of a proper initial neurological assessment onto the treatment management of patients admitted into Timisoara County Clinical Emergency Hospital's Emergency Unit.

MATERIALS AND METHODS

This is a retrospective study based on patients with thoracolumbar fractures between 2004 and 2009. Age, sex, cause and level of injury, fracture pattern and distribution, and neurological presentation of patients were studied.

RESULTS

There were 605 patients with predominance of men (59.17 %); the mean age was 32.4 years old. The main cause of the fractures was represented by car accidents (56.2 %), and associated trauma was found in 38.51 % of the patients. The majority of the patients presented with incomplete neurological deficit (45.62 %), whilst 20.66 % suffered from complete neurological deficit.

CONCLUSION

We found a correlation between the fracture level and the neurological deficit, the grade of neurological motor deficit and anal sphincter disorder and stenosis grade in relation to neurological lesions.

Morphological cervical disc analysis applied to traumatic and degenerative lesions

Trauma and degenerative pathologies at the lower cervical spine are different from lumbar spine pathologies. However, the description of cervical discs is classically taught similarly to that of the lumbar discs. Recent studies have raised this issue, and in 1999, Mercer and Bogduk described ventral annulus fibrosus as a crescent-shaped interosseous ligament. We propose a metric analysis of the different components of the cervical disc to examine this description. We analyzed 140 sagittal and coronal transections of 35 discs. These discs were taken from seven cervical spines at the five lower levels, C2-C3, C3-C4, C4-C5, C5-C6 and C6-C7. We measured quantitative parameters on sagittal, para-sagittal, ventral coronal and dorsal coronal colored transections: disc length (L), ventral annulus thickness (VAF), lateral annulus thickness (LAF), dorsal annulus thickness (DAF), length of the fibrocartilaginous tissue (FC), sagittal and coronal fibrocartilaginous core ratio (% Core) and intra-disc cleft length (Cleft). We also measured two qualitative parameters: degenerative disease of cartilaginous end plates and total intra-disc cleft. Finally, we examined 114 transections, and 18.5% were ruled out. The results showed thick ventral annulus fibrosus, thin lateral annulus and a very thin dorsal annulus. Fibrocartilaginous tissue filled the dorsal sagittal half of the disc. Intra-disc cleft split the fibrocartilaginous tissue and spread through the ventral annulus only six times. The shape of the ventral annulus at the lower cervical spine is compared to a pivot-hinge device. The aspect is functionally discussed in regard to teardrop fractures, unilateral locked facet syndrome and degenerative changes in the unco-vertebral area.

Elastic reinforcement and thickness of the joint capsules of the lower cervical spine

Mechanical studies have shown the major strength of the joint capsules of the lower cervical spine, especially in its ventrolateral part. The aim of this study was to examine the structure of the joint capsules in order to discover if there is a correspondence between biomechanical properties and descriptive anatomy. Ten transverse sections and 4 sagittal sections obtained from 6 cadavers were observed under light microscopy at X 25 to X 250 magnification. Standard stains and specific elastic fiber stain were used for histologic preparation. The data were the thickness of the joint capsules in the different quadrants, and the topography and direction of the elastic fibers. The results showed that the ventrolateral part of the joint capsules is thick and reinforced by oblique elastic fibers. The dorsal part is thin. The authors suggest that the descriptive anatomy of the joint capsules confirms their mechanical properties. They note that the role of the ventrolateral part is supplemented by that of the posterior longitudinal ligament for the stability of the functional cervical spinal unit.