Following a diagnostic or combination diagnostic / therapeutic sacroiliac joint injection, the patient's pain level is assessed by having the patient perform activities that would usually provoke pain. The percentage of pain relief is documented and a physical examination is performed. A positive response is defined as at least 75 percent improvement of the patient's painful activity related symptoms. If a second diagnostic injection is positive, then the sacroiliac joint is considered the likely source of the patient's painful symptoms.
While containers are usually made from a single type and color of plastic, making them relatively easy to sort, a consumer product like a cellular phone may have many small parts consisting of over a dozen different types and colors of plastics. In such cases, the resources it would take to separate the plastics far exceed their value and the item is discarded. However, developments are taking place in the field of active disassembly , which may result in more product components being reused or recycled. Recycling certain types of plastics can be unprofitable as well. For example, polystyrene is rarely recycled because the process is usually not cost effective. These unrecycled wastes are typically disposed of in landfills , incinerated or used to produce electricity at waste-to-energy plants.