Additional Exploratory Photoelastic Studies in Stress Wave Propagation

In a previous report to the sponsor, the design and description of a high speed framing camera was presented along with several film strips representing the results of a series of qualitative investigations of dynamic stress wave phenomena. These studies included crack propagation, layered media, compressed bars and beams, and cross sections of rocket heads. As part of a continuing study in these and related fields, a final report is submitted covering (1) exploratory experimental studies of shock wave propagation initiated by explosive caps and by nitrogen shock wave impingement, and (2) theoretical studies of a series of dynamic stress wave problems carried out in conjunction with the overall problem

Balloon kyphoplasty in the treatment of metastatic disease of the spine: a 2-year prospective evaluation

There is currently little data on the longer term efficacy and safety of balloon kyphoplasty (BKP) in patients with metastatic vertebral compression fractures (VCFs). To prospectively assess the long-term efficacy and safety of BKP in treating thoracic and lumbar spinal metastatic fractures that result in pain or instability. Sixty-five patients (37 men, mean age: 66 years) underwent 99 BKP procedures. Patient-related outcomes of pain visual analogue scale (VAS) and Oswestry Disability Index were assessed pre- and post-operatively and after 3, 6, 12 and 24 months. Correction of vertebral height and kyphotic deformity were assessed by radiographic measurements. Mean pain VAS and Oswestry Disability Index significantly improved from pre- to post-treatment (P < 0.0001), this improvement being sustained up to 24-month follow up. A gain in height restoration and a reduction of the post-operative kyphotic angle were seen post-operatively and at 3 months although these radiographic outcomes returned to pre-operative levels at 12 months. BKP was associated with a rate of cement leakage and incidence vertebral fracture of 12 and 8%, respectively. No symptomatic cement leaks or serious adverse events were seen during the 24 months of follow up. BKP is a minimally invasive procedure that provides immediate and long-term pain relief and improvement in functional ability in selected patients with metastatic VCFs. The procedure appears to have good long-term safety

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