OBJECTIVE: To investigate the effects of posterior implant rigidity on spinal kinematics at adjacent levels by utilizing a cadaveric spine model with simulated physiological loading. METHODS: Five human lumbar spinal specimens (L3 to S1) were obtained and checked for abnormalities. The fresh specimens were stripped of muscle tissue, with care taken to preserve the spinal ligaments and facet joints. Pedicle screws were implanted in the L4 and L5 vertebrae of each specimen. Specimens were tested under 0 N and 400 N axial loading. Five different posterior rods of various elastic moduli (intact, rubber, low-density polyethylene, aluminum, and titanium) were tested. Segmental range of motion (ROM), center of rotation (COR) and intervertebral disc pressure were investigated. RESULTS: As the rigidity of the posterior rods increased, both the segmental ROM and disc pressure at L4-5 decreased, while those values increased at adjacent levels. Implant stiffness saturation was evident, as the ROM and disc pressure were only marginally increased beyond an implant stiffness of aluminum. Since the disc pressures of adjacent levels were increased by the axial loading, it was shown that the rigidity of the implants influenced the load sharing between the implant and the spinal column. The segmental CORs at the adjacent disc levels translated anteriorly and inferiorly as rigidity of the device increased. CONCLUSION: These biomechanical findings indicate that the rigidity of the dynamic stabilization implant and physiological loading play significant roles on spinal kinematics at adjacent disc levels, and will aid in further device development.
Aluminum ; Biomechanical Phenomena* ; Cadaver ; Humans ; Intervertebral Disc ; Ligaments ; Polyethylene ; Range of Motion, Articular ; Rubber ; Spine ; Zygapophyseal Joint

Voiding dysfunction is a common disease that contributes to a lower quality of life and has an increased prevalence in the elderly population. Noninvasive and objective methods such as uroflowmetry (UFM) and voiding diaries (VDs) are essential for exact diagnosis and effective treatment of this condition because patients with different causes of voiding dysfunction can complain of the same lower urinary tract symptoms. Further, different treatment options can be determined based on the diagnosis made from these symptoms. In order to improve the quality of UFM and VDs and to provide a convenient testing environment, several advances have been made by previous investigators. In this study, we investigate the history and technological mechanisms of UFM and VDs. We also aim to review UFM from the viewpoint of clinical and at-home uses, including the recently proposed toilet-shaped UFM and electronic VDs.
Aged ; Diagnosis ; Humans ; Lower Urinary Tract Symptoms ; Mobile Health Units ; Monitoring, Ambulatory ; Prevalence ; Quality of Life ; Research Personnel

OBJECTIVE: Radiation is used extensively in emergency centers. Computed tomography and X-ray imaging are used frequently. Portable X-rays, in particular, cause a significant amount of indirect radiation exposure to medical personnel. The authors' emergency center was remodeled, and a comparative study of radiation exposure was carried out in certain places that had experienced radiation for a long time. METHODS: The cumulative radiation dose was measured 20 times in the 24 hours prior to remodeling, and the cumulative radiation dose was measured again 20 times across the 24-hour period. The measurement points were fixed at the emergency doctor's seat (Zone A), charge nurse's seat (Zone B), and section nurse's seat (Zone C). During the 24-hour cumulative radiation measurement period, the number of portable X-ray shots was recorded in the emergency center. RESULTS: The mean of the 24-hour cumulative radiation measurements in zone A was 3.36±0.07 µSV and 4.54±0.07 µSV before and after remodeling, respectively (P<0.001). Regarding the number of portable X-rays performed during the measurement, a higher number of trials in the Pearson correction correlated with a higher radiation measurement. CONCLUSION: In an emergency medical center, there is a higher level of low-dose radiation exposure compared to that experienced from natural radioactivity. Regarding the number of portable X-rays, the cumulative radiation dose measured 24 hours after remodeling increased and can be assumed to be related to the environment.
Emergencies ; Radiation Exposure ; Radioactivity