ABSTRACT
Objective To analyze and summarize the gait characteristics of patients with sciatica, so as to assist with diagnosis and evaluation for such patients in clinic. Methods Forty-three patients with lumbar disc herniation accompanied by siatica were fitted with portable gait analyzer, and required to walk at the self-selected comfortable speed for a distance of 120 m. Forty-three healthy subjects with matched age, gender and body mass index (BMI) were recruited as control. The gait data including 7 spatial-temporal parameters (single-support duration, double-support duration, ratio of single-support duration to double-support duration, duration of gait cycle, step speed, step frequency, step length) and 4 acceleration parameters (pulling acceleration, swing power, ground impact, foot fall) were collected to compare the gait differences between patients and healthy subjects, as well as between affected and healthy limbs of patients. Results The single-support duration, ratio of single-support duration to double-support duration, step speed, step frequency, step length and four acceleration parameters of patients with sciatica were obviously smaller than those of healthy subjects, while the double-support duration of patients with sciatica was increased. The affected limb of patients with sciatica showed a significant decrease in single-support duration, step frequency and all four acceleration parameters but increase in step length as compared to their healthy limbs. Conclusions Patients with sciatica have significant gait abnormalities due to their affected limbs, which influence their walking ability. Portable gait analyzer can be used for objectively characterizing the walking abnormalities of patients, so as to provide additional information for the clinical diagnosis and evaluation.
ABSTRACT
Objective To observe the obstacle of mandible to the cervical spine with the aid of dual fluoroscopic imaging system, explore the optimal perspective Methods of in vivo kinematics of cervical spine, and verify the feasibility of cervical in vivo kinematic researches. Methods A dual fluoroscopic imaging system composed of two C-arms placed in different angles was utilized. X ray images of the cervical spine for five healthy volunteers (4 male, 1 female) with standing, flexion extension, twisting and bending positions were obtained with the C-arms in the angle of 90°, 60°and 45°, respectively. The obstacles of mandible to the cervical spine in different positions were compared and the obstacle degree of mandible to the cervical spine was evaluated to screen the optimal perspective Methods. The perspective images under conventional head rotation and coaxial trunk rotation were collected during cervical twisting to compare the obstacle of mandible to cervical images. Results There were significant differences in mandibular obstacle degrees among the three angles measured in standing, flexion-extension, twisting and bending positions（P<0.05）. With two C-arms in 45°, the cervical spine was best imaged with the least obstacle. With two C-arms in 60°, significant differences could be found between the coaxial trunk rotation and the head rotation group. Conclusions For in vivo kinematics study of cervical spine, the obstacle of mandible to the cervical spine can be minimized with C-arms of dual fluoroscopic imaging system in 45°, and the coaxial trunk rotation can decrease the mandibular obstacle degrees as compared with the head rotation, which satisfy the requirement of 2D-3D image matching.
ABSTRACT
<p><b>BACKGROUND</b>Accurate knowledge of the spinal structural functions is critical to understand the biomechanical factors that affect spinal pathology. Many studies have investigated the human vertebral motion both in vitro and in vivo. However, determination of in vivo motion of the vertebrae under physiologic loading conditions remains a challenge in biomedical engineering because of the limitations of current technology and the complicated anatomy of the spine.</p><p><b>METHODS</b>For in vitro validation, a human lumbar specimen was imbedded with steel beads and moved to a known distance by an universal testing machine (UTM). The dual fluoroscopic system was used to capture the spine motion and reproduce the moving distance. For in vivo validation, a living subject moved the spine in various positions while bearing weight. The fluoroscopes were used to reproduce the in vivo spine positions 5 times. The standard deviations in translation and orientation of the five measurements were used to evaluate the repeatability of technique. The accuracy of vertebral outline matching with metallic marks matching technology was compared.</p><p><b>RESULTS</b>The translation positions of the human lumbar specimen could be determined with a mean accuracy less than 0.35 mm and a mean repeatability 0.36 mm for the image matching technique. The repeatability of the method in reproducing in vivo human spine six degrees of freedom (6DOF) kinematics was less than 0.43 mm in translation and less than 0.65° in rotation. The accuracy of metallic marks and vertebral outline matching did not show significant difference.</p><p><b>CONCLUSIONS</b>Combining a dual fluoroscopic and computerized tomography imaging technique was accurate and reproduceable for noninvasive measurement of spine vertebral motion. The vertebral outline matching technique could be a useful technique for matching of vertebral positions and orientations which can evaluate and improve the efficacy of the various surgical treatments.</p>