In addition to enhancing thermal ablation of tissue, the intense activity of cavitation bubbles induced by focused ultrasound can also produce mechanical effects. These can be exploited for the minimally invasive removal of diseased tissue.
One of the projects ongoing in the IBME seeks to apply this to the treatment of spinal disease. Four out of five adults will suffer from low back pain during their lifetime and around 5% of sufferers become chronically disabled. This imposes a high economic and social burden on society because the disorder affects people of working age as well as the elderly, with the total cost being estimated to be over 1 % of the UK's GDP. Low back pain is strongly associated with degeneration of the intervertebral discs, the soft tissues that connect the spinal vertebrae and allow the spine to articulate. Current surgical treatments for low back pain are highly invasive and have relatively low long term success rates. The present work aims to develop a novel, minimally invasive therapy for disc replacement without the need for surgical incision. If successful, it has the potential to revolutionise clinical practice for the treatment of back pain, thus improving quality of life and reducing the economic impact of this major disease.
In this project we will employ high intensity focused ultrasound to fractionate degenerated tissue in a tightly controlled region so that it can be easily removed by minimally invasive needle. A new class of self assembling peptide gels will then be injected through the same needle into the cavity to restore the disc's mechanical function. These developments will involve a combined programme of computational and experimental modelling of the acoustics and mechanics of the disc and the surrounding vertebral structures in order to optimise the performance of the procedure across the likely variance in disc properties seen in a typical patient population.