Influence of Handgrip Strength and Paraspinal Muscles' Volume on Clinical Outcomes in the Patients With Each Sagittal Imbalance and Lumbar Spinal Stenosis.

STUDY DESIGN: Cross-sectional study. OBJECTIVE: To compare handgrip strength (HGS), paraspinal muscles' (PSM) volume, and their effects on clinical symptom severity between the patients with sagittal imbalance (SI) and symptomatic lumbar spinal stenosis (LSS). METHODS: A total of 54 paired consecutive patients with SI and LSS were enrolled after propensity score matching. Preoperative HGS, cross-sectional area (CSA) of psoas (PS) and multifidus (MF) muscles, and patient-reported measures, including visual analog scale (VAS) for back/ leg pain, Oswestry Disability Index (ODI), and EuroQOL (EQ-5D) were compared between both groups. Within each SI and LSS group, patient-reported measures were compared between high and low HGS subgroups. The correlation of HGS and CSA of PSMs to patient-reported measures was evaluated. RESULTS: There was no difference in HGS between 2 groups, however, the CSA of PS and MF muscles in SI group was significantly lower than those in LSS group. Patients with low HGS showed inferior results for ODI and EQ-5D, compared to those with high HGS subgroup in both SI and LSS groups. HGS and CSA of MF muscle were correlated with ODI in both groups. CONCLUSIONS: There was no significant difference between the SI and LSS groups in HGS, however, PSMs' volume in SI group were significantly lower than those in LSS group. Therefore SI would be associated with loss of localized muscle mass in back area, rather than global skeletal muscle weakness. HGS and PSMs' volume were adversely associated with functional status in SI and LSS patients.

Serial Changes in Image Findings of Herniation Pits from the First Appearance.

BACKGROUD: Herniation pits (HPs) have been considered to be an incidental finding, but recently femoroacetabular impingement (FAI) has been proposed as a possible cause of their formation. The findings on bone scans of HPs are variable in the literature: some showed increased uptake; the majority did not. We hypothesized that serial changes in image findings of HPs would explain the reason for the variable bone scan findings. METHODS: Four patients (5 hips) were followed up for more than 7 years. All patients were women and regularly underwent bone scintigraphy after the diagnosis of breast cancer. Small lesions with increased uptake were first detected on bone scintigraphy at the age of 44 to 64 years. In all cases, the lesions were confirmed by magnetic resonance imaging and follow-up bone scintigrams were taken regularly. Four lesions were also evaluated by computed tomography. Changes in the size of the pits and the intensity of the increased uptake on bone scintigraphy were evaluated. RESULTS: On the bone scintigrams, the lesions with increased uptake were detected in the femoral neck at 5-20 months after previous negative bone scintigraphy. There had been no events or symptoms associated with the newly detected increased uptake. On follow-up scans, the intensity of the uptake decreased gradually and the areas of increased uptake disappeared completely at 14-50 months after their first appearance. In 3 cases (2 patients), the pit size increased during follow-up. CONCLUSIONS: The areas of increased uptake on bone scintigraphy gradually disappeared in all cases and the increase in pit size was frequent. There was no case in which signs or symptoms suggestive of FAI were noticed.

Ceramic Liner Fracture Caused by an Impingement between the Stem Shoulder and the Ceramic Liner.

Mechanisms of ceramic liner fractures have not yet been fully elucidated. Impingement between a stem and ceramic liner is a proposed cause of ceramic liner fractures. We experienced a case of ceramic liner fracture caused by direct impingement between the stem shoulder and the ceramic liner. This type of impingement, unlike impingements with a stem neck, has not been previously reported. While we assume that certain characteristics of the stem contributed to the impingement, we report this case to note that caution may be needed when using certain stem designs.

Sleep Disturbance in Patients With Lumbar Spinal Stenosis: Association With Disability and Quality of Life.

STUDY DESIGN: This was a cross-sectional cohort study. OBJECTIVE: The objective of this study was to identify the prevalence of sleep disturbance in patients with symptomatic lumbar spinal stenosis (LSS) and to establish the relationship between sleep disturbance and both functional disability and health-related quality of life in patients with symptomatic LSS. SUMMARY OF BACKGROUND DATA: Despite the possible association between LSS and poor sleep quality, there has been no study regarding the relationship between LSS and sleep disturbance. MATERIALS AND METHODS: A total of 148 patients with LSS were divided into the poor sleeper and nonpoor sleeper groups according to Global Pittsburgh Sleep Quality Index (PSQI) score. Demographic data, Visual Analog Scale (VAS) score for back and leg pain, Oswestry Disability Index (ODI), and EuroQol 5-dimension questionnaire (EQ-5D) were compared between both groups. Multiple regression analysis was performed with ODI or ODI without sleep component as the dependent variable and age, sex, PSQI, VAS for back pain, VAS for leg pain as independent variables. RESULTS: Of the 148 patients who participated in this study, 54 (36.5%) and 94 (63.5%) patients were classified into nonpoor sleeper and poor sleeper groups. Although there were no differences in demographic data or VAS for back or leg pain between the nonpoor sleeper and poor sleeper groups, poor sleepers demonstrated significantly higher ODI scores, and lower EQ-5D than nonpoor sleepers (P=0.003 and 0.004, respectively). There were significant correlations between the global PSQI score and both the ODI score and EQ-5D. Although the surgical treatment group showed significantly higher VAS for back pain, VAS for leg pain, ODI scores, and lower EQ-5D than the conservative treatment group, the ratio of poor to nonpoor sleepers was not different between both groups (P=0.733). In the surgical treatment group, the percent of poor sleeper decreased from 65.1% to 47.6% 6 months after surgery (P<0.001). CONCLUSIONS: The present study demonstrated that 'poor sleep quality' is a prevalent condition (63.5%) in patients with symptomatic LSS. Poor sleep quality has an adverse effect on functional disability and health-related quality of life in symptomatic LSS patients.

Wind-drag estimation in a traffic accident involving a motor scooter and a tractor-trailer.

This case report describes a noncontact traffic accident involving a motor scooter and a tractor-trailer with a focus on the wind-drag effect. We used load cells to measure the drag force acting on a substantially similar motor scooter when a substantially similar tractor-trailer passes by it, taking into consideration various speeds of the tractor-trailer and distances between the two vehicles. A three-dimensional steady-state flow analysis was also performed by using the CFX program for computational fluid dynamics to examine the streamlines and the pressure distribution around the tractor-trailer at various speeds. From the experiment, for a separation distance of 1.0 m (3.28 ft) and a speed of 90 km/h (55.9 mph), the maximum resultant drag force is 124.5 N (28 lb); this constitutes a degree of force that could abruptly disrupt the stability in maneuvering by an operator who is unaware of the approaching tractor-trailer. In addition, a single equation that relates the tractor-trailer speed to the drag force that acts on the motor scooter was derived on the basis of the Reynolds number (Re) and the wind-drag coefficient (C(d)): C(d) = 1.298 × 10(-7) Re.

An explosion of a CNG fuel vessel in an urban bus.

An investigation is presented of the explosion of a CNG (compressed natural gas) fuel vessel, called a liner, in an urban bus. The explosion happened at a gas station 10 min after filling was completed. There were no traces of soot and flames at the failed liner, which would be indicative of explosion by ignition of the gas. The filling process of the station was automatically monitored and recorded in a computer. There was no unusual record of the filling system that indicated excess pressure at the time of the accident. There were cracks on the liner that were initiated at the outer surface of the cylindrical shell located at a point 4 cm above the lower dome where cracks did not originate easily as a result of overload. Chemical analysis was performed on a specimen that was cut from the liner, and there was no peculiarity in the mix. Mechanical analysis was performed on the specimens and showed that the hardness was not in the specified range because of inadequate heat treatment of the metal. The hardness of the liner was strictly controlled in the manufacturing process. All the liners that were manufactured at the same period with the failed liner were recalled for examination.