Complex sentence: Beginning in 2001, the trials were carried out by Heidelberg University, the University of Marburg, the University of Mainz and the Ruhr University Bochum for low back pain, knee osteoarthritis, migraine prophylaxis, and tension-type headache.
Split into simpler sentences: Beginning in 2001, the trials were carried out by Heidelberg University, the University of Marburg, the University of Mainz and the Ruhr University Bochum. There were separate trials for four indications: low back pain, knee osteoarthritis, migraine prophylaxis, and tension-type headache.