RESUMO
PURPOSE: This work aimed to evaluate and characterize the motion of the fourth and fifth lumbar vertebrae functional spinal unit with spondylolysis and different types of grade 1 spondylolisthesis using the finite element method. METHODS: Nine nonlinear three-dimensional finite element models were reconstructed from computed tomography scans to five educational fourth and fifth lumbar vertebrae models. The intervertebral disc was simulated in two conditions: four models with healthy discs and five models with degenerated discs. Each model consisted of two vertebrae divided into three bony parts, two endplates, an intervertebral disc and five ligaments. The flexion, extension, lateral bending and rotation loading conditions were simulated, and the ranges of motion were measured and plotted. RESULTS: In flexion, compared to the baseline intact model, the most significant increase in the range of motion was experienced by the isthmic spondylolisthesis model, while in extension, a reduction in the range of motion was measured in both prolonged pars and unilateral pars defect and healthy disc models. In degenerated disc results, the unilateral pars defect and degenerative spondylolisthesis models had the lowest range of motion. No large differences were noticed in lateral bending results. Lastly, in axial rotation, the most significant increase in the range of motion was measured in the isthmic spondylolisthesis model, followed by the spondylolysis model and similarly, in the degenerated disc models. CONCLUSIONS: The isthmic spondylolisthesis displayed hypermobility in flexion and rotation. Moreover, the model with unilateral pars defect showed hypermobility in axial rotation only. Finally, hypomobility in all movements was noticed with the degenerative spondylolisthesis model.
RESUMO
BACKGROUND: Increased intracranial pressure (ICP) is frequently seen, and it is considered a serious problem that needs a careful assessment and management, especially by easy and least invasive modalities. OBJECTIVE: The objective of the study is to assess the optic nerve sheath diameter (ONSD) using transorbital ultrasound (US) as a marker and indicator for diagnosing raised intracranial pressure. PATIENTS AND METHODS: It is a prospective study that was carried out in Neurology and/or Ophthalmology Clinics, Baghdad Teaching Hospital in the Medical City Complex during the period from June 2016 to May 2017; in this study, 40 patients seeking medical help for other causes were considered to be a control group and the other 40 patients who were complaining of raised ICP symptoms and suggested of having optic disc swelling by ophthalmoscopy examination. All the patients and the control group were examined by transorbital US to measure the ONSD, and then, only the patients with symptoms of raised intracranial underwent a lumbar puncture (LP). RESULTS: Pearson's correlation test was used, demonstrating a very significant correlation between the ultrasonographic ONSD and the measurements of LP (R > 0.9) and (P < 0.001). Transorbital US yielded high sensitivity (91.6%) with modest specificity (75%) and high accuracy (90.0%) of ONSD was considered the normal the cutoff value of (5 mm) obtained from the control group. The US also showed the crescent sign and the optic disc bulging with lower sensitivity than the ONSD (61.1% and 41.6%, respectively) but with very high specificity (100%) for both. CONCLUSION: ONSD by transorbital ultrasonography is highly accurate, easily performed, and noninvasive procedure for the detection of raised ICP. Routine daily monitoring of ONSD could be of help in intensive care units when invasive ICP monitoring is not available or contraindicated; it also has a good role in early recognition of intracranial hypertension.
