The wire therefore guides the larger cannulae into the joint. They have a unique cell structure involving a network of cannulae and flat, disk-shaped cells. Stainless steel cannulae tend to collapse when cut with wire cutters. While the syringes are not the same as cannulae, the techniques remain relevant. Intravenous cannulae are the most common in hospital use. A variety of cannulae are used to establish cardiopulmonary bypass in cardiac surgery. Oxygen can be insufflated into the nose by nasal cannulae to assist in respiration. Cannulae normally come with a trocar inside. The cannulae branch out and connect with other cells, greatly extending their range. Cannulae are hollow flexible tubes of varying bore, usually 16-22 gauge thick.