Explosive shielding by weak layers

This paper presents the results of a series of computations which were carried out to determine the effect that a layer of extremely weak rock embedded in an otherwise strong rock matrix would have on the displacements and velocities which result from the detonation of a nearby explosive source. The motivation for the study was the apparently different measurements obtained on the Mission Cyber Nuclear Event when compared to results obtained from other events of equal yield in similar geologic media

Reliability of the Spinal Instability Neoplastic Score (SINS) among radiation oncologists: an assessment of instability secondary to spinal metastases

BACKGROUND: The Spinal Instability Neoplastic Score (SINS) categorizes tumor related spinal instability. It has the potential to streamline the referral of patients with established or potential spinal instability to a spine surgeon. This study aims to define the inter- and intra-observer reliability and validity of SINS among radiation oncologists. METHODS: Thirty-three radiation oncologists, across ten international sites, rated 30 neoplastic spinal disease cases. For each case, the total SINS (0-18 points), three clinical categories (stable: 0-6 points, potentially unstable: 7-12 points, and unstable: 13-18 points), and a binary scale (‘stable’: 0-6 points and ‘current or possible instability’; surgical consultation recommended: 7-18 points) were recorded. Evaluation was repeated 6-8 weeks later. Inter-observer agreement and intra-observer reproducibility were calculated by means of the kappa statistic and translated into levels of agreement (slight, fair, moderate, substantial, and excellent). Validity was determined by comparing the ratings against a spinal surgeon’s consensus standard. RESULTS: Radiation oncologists demonstrated substantial (κ = 0.76) inter-observer and excellent (κ = 0.80) intra-observer reliability when using the SINS binary scale (‘stable’ versus ‘current or possible instability’). Validity of the binary scale was also excellent (κ = 0.85) compared with the gold standard. None of the unstable cases was rated as stable by the radiation oncologists ensuring all were appropriately recommended for surgical consultation. CONCLUSIONS: Among radiation oncologists SINS is a highly reliable, reproducible, and valid assessment tool to address a key question in tumor related spinal disease: Is the spine ‘stable’ or is there ‘current or possible instability’ that warrants surgical assessment

C2 prosthesis: anterior upper cervical fixation device to reconstruct the second cervical vertebra

Destruction of the second cervical vertebra leads to a highly unstable situation. Reconstruction is difficult because the axis plays a central role in rotatory movements and has a unique function in redistributing axial loads. The axis transfers the axial load of the two lateral masses of the atlas to three surfaces on the third cervical vertebra: the two articular facets and the vertebral body. As reconstruction is difficult and the instability in this region is life threatening, pathological processes are often treated less radically compared to other areas of the cervical spine. However, this more moderate approach may result in worse outcomes and prognoses. This paper presents the development of a new implant (C2 prosthesis) and two illustrative cases describing the implementation of this new implant. The C2 prosthesis provides anterior support and therefore allows a more radical surgical approach

Balloon kyphoplasty in malignant spinal fractures: a systematic review and meta-analysis

<p>Abstract</p> <p>Background</p> <p>Spinal fractures are a common source of morbidity in cancer patients. Balloon Kyphoplasty (BKP) is a minimally invasive procedure designed to stabilize fractures and correct vertebral deformities. We performed a meta-analysis to determine the efficacy and safety of BKP for spinal fractures in cancer patients.</p> <p>Methods</p> <p>We searched several electronic databases up to September 2008 and the reference lists of relevant publications for studies reporting on BKP in patients with spinal fractures secondary to osteolytic metastasis and multiple myeloma. Outcomes sought included pain relief, functional capacity, quality of life, vertebral height, kyphotic angle and adverse events. Studies were assessed for methodological bias, and estimates of effect were calculated using a random-effects model. Potential reasons for heterogeneity were explored.</p> <p>Results</p> <p>The literature search revealed seven relevant studies published from 2003 to 2008, none of which were randomized trials. Analysis of those studies indicated that BKP resulted in less pain and better functional outcomes, and that these effects were maintained up to 2 years post-procedure. While BKP also improved early vertebral height loss and spinal deformity, these effects were not long-term. No serious procedure-related complications were described. Clinically asymptomatic cement leakage occurred in 6% of all treated levels, and new vertebral fractures in 10% of patients. While there is a lack of studies comparing BKP to other interventions, some data suggested that BKP provided similar pain relief as vertebroplasty and a lower cement leakage rate.</p> <p>Conclusion</p> <p>It appears that there is level III evidence showing BKP is a well-tolerated, relatively safe and effective technique that provides early pain relief and improved functional outcomes in patients with painful neoplastic spinal fractures. BKP also provided long-term benefits in terms of pain and disability. However, the methodological quality of the original studies prevents definitive conclusions being drawn. Further investigation into the use of BKP for spinal fractures in cancer patients is warranted.</p

Clinical management of pain in advanced lung cancer

Lung cancer is the most common cancer in the world and pain is its most common symptom. Pain can be brought about by several different causes including local effects of the tumor, regional or distant spread of the tumor, or from anti-cancer treatment. Patients with lung cancer experience more symptom distress than patients with other types of cancer. Symptoms such as pain may be associated with worsening of other symptoms and may affect quality of life. Pain management adheres to the principles set out by the World Health Organization's analgesic ladder along with adjuvant analgesics. As pain can be caused by multiple factors, its treatment requires pharmacological and non-pharmacological measures from a multidisciplinary team linked in with specialist palliative pain management. This review article examines pain management in lung cancer

Diagnostic algorithm, prognostic factors and surgical treatment of metastatic cancer diseases of the long bones and spine

Oncological management of skeletal metastases has changed dramatically in the last few decades. A significant number of patients survive for many years with their metastases.Surgeons are more active and the technical repertoire is broader, from plates to intramedullary devices to (tumour) endoprostheses.The philosophy of treatment should be different in the case of a trauma-related fracture and a pathological fracture. A proper algorithm for establishing a diagnosis and evaluation of prognostic factors helps in planning the surgical intervention.The aim of palliative surgery is usually to eliminate pain and to allow the patient to regain his/her mobility as well as to improve the quality of life through minimally invasive techniques using life-long durable devices.In a selected group of patients with an oncologically controlled primary tumour site and a solitary bone metastasis with positive prognostic factors, which meet the criteria for radical excision (approximately 10% to 15% of the cases), a promising three to five years of survival may be achieved, especially in cases of metastases from breast and kidney cancer.Spinal metastases require meticulous evaluation because decisions on treatment mostly depend on the tumour type, segmental stability, the patient's symptoms and general state of health.Advanced radiotherapy combined with minimally invasive surgical techniques (minimally invasive stabilisation and separation surgery) provides durable local control with a low complication rate in a number of patients. Cite this article: EFORT Open Rev 2017;2:372-381

Vertebroplasty and kyphoplasty: a comparative review of efficacy and adverse events

Vertebroplasty and kyphoplasty have become common surgical techniques for the treatment of vertebral compression fractures. Vertebroplasty involves the percutaneous injection of bone cement into the cancellous bone of a vertebral body with the goals of pain alleviation and preventing further loss of vertebral body height. Kyphoplasty utilizes an inflatable balloon to create a cavity for the cement with the additional potential goals of restoring height and reducing kyphosis. Vertebroplasty and kyphoplasty are effective treatment options for the reduction of pain associated with vertebral body compression fractures. Biomechanical studies demonstrate that kyphoplasty is initially superior for increasing vertebral body height and reducing kyphosis, but these gains are lost with repetitive loading. Complications secondary to extravasation of cement include compression of neural elements and venous embolism. These complications are rare but more common with vertebroplasty. Vertebroplasty and kyphoplasty are both safe and effective procedures for the treatment of vertebral body compression fractures

Study of fracture pressurization as a result of explosive detonation

This paper describes a number of model tests conducted in plexiglas models to investigate the phenomenon of fracture pressurization. The models were examined with high speed photography while being subjected to explosive loading. At the same time pressure transducers were used to record the pressure in the borehole as a function of time and also along the path of the propagating fracture to measure the pressure at various locations along the fracture as a function of time. Both propellants and explosives were used to charge the borehole. Air as well as fluid filled boreholes were needed to provide a variety of pressure rise rates. On some tests eddy current displacement gauges measured crack opening displacements as a function of time. As a final check high speed photographs taken during the event were used to visually ascertain the location of the fracture at any given time. 6 references, 10 figures