Ultrasound bone fixing device approved for NHS use Doctors at the National Institute for Clinical Excellence (Nice) have approved the Exogen ultrasound system for use in those with bone fractures that have not healed after nine months. The device delivers low-intensity pulsed ultrasound waves which, according to Nice, "aim to promote bone healing through stimulating the production of growth factors and proteins which increase the removal of old bone, and increase the production of new bone." Patients use the devices themselves, at home, for 20-minute sessions. Nice found that the Exogen system led to cost savings of more than £1,000 per patient with "non-union fractures" - those that had failed to heal nine months after a break. This was because surgery was sometimes avoided. However, Nice refused to allow it to be used in those with breaks that had failed to heal up to nine months after a break, saying there was "too much uncertainty" about how useful it was.