An Investigation on Failure of Embankments in Bangladesh

The study presents the results of case histories on failure of embankments in Bangladesh based on the field visits to the embankments sites, collected data and information on failure of embankments necessary data related to embankments construction practice obtained from available publications and soil conditions of the breached embankments in Bangladesh. Efforts have been made to discuss briefly the causes of embankment failure and its possible remedial measures. Two recent failures of embankments that occurred in the year 2007 are taken into consideration for a detailed study. For each case, embankment failure mechanism, construction method used for the embankments, soil conditions, embankment geometry and water levels are collected and analyses are made for slope stability with and without water storage conditions. Soil samples collected during field visits are analyzed. On the basis of the results of analyses and discussions, it is concluded that the major causes of failure of earlier embankments are identified as breach of the embankment, cutting by public, overflow, erosion, seepage and sliding. Other causes were poor planning, design and faulty construction. The cause of failure of all the flood control embankments in the year 2007 could be attributed to erosion and sliding of embankment materials due to river encroachment and mitigation. Slope stability analyses of the Padma and Jamuna flood control embankments revealed that the country side slopes of both the embankments are not at all stable during the monsoon when the water level is high. The Jamuna flood control embankment is not stable even before and after the monsoon period because the factor of safety calculated for the country side slopes are less than that of the recommended one. Of the two cases studied detailed in this research articles, it is observed that there are substantial differences between the cross sections shown in the actual designs that existed near to the failure locations. A close investigation of the above two cases indicates that no protective measures such as mattressing, stone pitching, concrete layers, artificial or natural reinforcement like grassing, soil-cement layer are made to prevent the embankments from rain splash, water current, waves, storm surges, and other natural calamities and destructive forces. It is recommended that the embankments should be constructed by following the proper design and construction procedure, and be protected by using some forms of reinforcements or surface covering/treatment

Consecutive assessment of FA and ADC values of normal lumbar nerve roots from the junction of the dura mater

Background: Diffusion weighted imaging (DWI) and diffusion tensor imaging (DTI) are widely used in the evaluation of the central nervous system and recently have been reported as a potential tool for diagnosis of the peripheral nerve or the lumbar nerve entrapment. The purpose of this study was to evaluate consecutive changes in apparent diffusion coefficient (ADC) and fractional anisotropy (FA) values of normal lumbar nerve roots from the junction of the dura mater. Methods: The lumbar spinal nerves were examined in 6 male healthy volunteers (mean age, 35 years) with no experiences of sciatica, with a 3.0-T MR unit using a five-element phased-array surface coil. DTI was performed with the following imaging parameters: 11084.6/73.7 ms for TR/TE; b-value, 800 s/mm2; MPG, 33 directions; slice thickness, 1.5 mm; and total scan time, 7 min 35 s. ADC and FA values at all consecutive points along the L4, L5 and S1 nerves were quantified on every 1.5 mm slice from the junction of the dura mater using short fiber tracking. Results: ADC values of all L4, 5, and S1 nerve roots decreased linearly up to 15 mm from the dura junction and was constant distally afterward. ADC values in the proximal portion demonstrated S1 > L5 > L4 (p L5 > S1 (p < 0.05). Conclusion: Our study demonstrated that ADC and FA values of each L4, 5, and S1 at the proximal portion from the junction of the dura matter changed linearly. It would be useful to know the normal profile of DTI values by location of each nerve root so that we can detect subtle abnormalities in each nerve root

Effects of rehabilitation program for an anatomical abnormality

Introduction : Spina bifida occulta (SBO) is a common malformation of lamina of the spine, most commonly occurring in the sacrum or lower lumbar spine. Athletes with anatomical abnormalities such as SBO may be vulnerable to discoordination of muscles and/or skeletal structures. Case Report : We present a case of a 15-year-old male adolescent who presented with persistent low back pain (LBP) associated with SBO at T11-L1 that had been overlooked for several years. He participated in karate as a top-level competitor at the nationallevel, but the LBP interfered with his play. Dynamic X-ray films showed limited range of motion (ROM) in his lower lumbar spine (L3-S1). Instead, the thoracolumbar junction compensated for the lack of ROM in the lumbar spine, enabling trunk flexion and extension. To restore normal coordination, he was treated with a 2-week rehabilitation program including flexibility and core conditioning for the trunk to improve coordination of spinal movement. Two weeks later, his LBP resolved. Conclusion : These results suggest that evaluation of the coordination of the muscles and skeletal structures has an important role in the treatment of cases with an anatomical abnormality such as SBO

Blocking the k-Holes of Point Sets in the Plane

Let P be a set of n points in the plane in general position. A subset H of P consisting of k elements that are the vertices of a convex polygon is called a k-hole of P, if there is no element of P in the interior of its convex hull. A set B of points in the plane blocks the k-holes of P if any k-hole of P contains at least one element of B in the interior of its convex hull. In this paper we establish upper and lower bounds on the sizes of k-hole blocking sets, with emphasis in the case k=5

MRI Changes of the Spinal Subdural Space after Lumbar Spine Surgeries: Report of Two Cases

Although magnetic resonance imaging (MRI) is frequently used to assess the lumbar spine, there are few reports in the medical literature that have evaluated using MRI immediately following spinal surgery. Furthermore, descriptions of the subdural changes after lumbar spine surgery are also infrequent. In this paper, we present two cases with subdural change seen on MRI immediately after lumbar surgery. Both the patients had mild symptoms that resolved spontaneously, and the follow-up MRI scans showed resolution of the subdural changes. Subdural changes should be considered as one of the possible causes of unexpected symptoms in patients following lumbar spinal surgery

Myelopathy due to C2 Spondylolysis

We report a case with compression myelopathy due to proliferative changes around the C2 pars defects without instability. A 69-year-old man presented with progressive clumsy hands and spastic gait. Plain radiographs showed bilateral spondylolysis (pars defects) at C2 and fusion between C2 and C3 spinous processes. Dynamic views revealed mobility through the pars defects, but there was no apparent instability. Computed tomography showed proliferative changes at the pars defects, which protruded into spinal canal. On magnetic resonance imaging, the spinal cord was compressed and intramedullary high signal change was found. A diagnosis of compression myelopathy due to proliferative changes around the C2 pars defects was made. We performed posterior decompression. Postoperatively, symptoms have been alleviated and images revealed sufficient decompression and no apparent instability. In patients with the cervical spondylolysis, myelopathy caused by instability or slippage have been periodically reported. The present case involving C2 spondylolysis is extremely rare

MRI of Early-Stage Lumbar Spondylolysis

Purpose : To analyze extraosseous signal changes (ESCs) on magnetic resonance imaging (MRI) in pediatric patients with stress fractures occurring in the lamina. Methods : This study was a retrospective review of 69 consecutive pediatric patients with stress fractures occurring in the lamina. We analyzed MRI scans obtained at the first presentation. Results : We used mainly axial short tau inversion recovery images acquired through the pedicle of these 84 fracture sites to identify the ESCs. These were then divided into three groups: “invisible” when no ESC was detected, “periosteal” for ESC seen on only the dorsal side of the lamina, and “perimuscular” for ESC distinctly spread around / in the paravertebral muscles. In total, 78 (92.9%) fracture sites showed ESCs on the dorsal side of the lamina among which 72 ESCs were located on only the “dorsal” side, while 6 ESCs were on the ventral side against the transverse process. Conclusion : ESCs on MRI were detected in more than 90% of patients before stress fracture became apparent in the lamina, which was considered similar to findings of periosteal thickening / edema detected at the onset of stress fracture in long bone

C6 radiculopathy with winged scapula

A 73-year-old woman complained of right medial side of scapular pain associated with winged scapula to miss without observing the back in minute detail. Additional treatment was required due to overlooking caused by insufficient examination. We performed micro-endoscopic foraminotomy that provided the disappearance of scapular pain and improvement of winged scapula in relatively early. It was commonly said that winged scapula is an extremely rare condition that causes dysfunction of the upper extremities. We suggest that there are the meaning of winged scapula in diagnosis and the importance of physical examination. Further studies should be required to research the morbidity of winged scapula associated with cervical disease. By sharing our experience of this attention arousing case, we provide information not to repeat the same mistakes