Complex sentence: The line carrying the drug may be threaded under the skin to emerge at the front of the patient, a process called tunneling, and is recommended with long term use so as to reduce the chance of any infection at the exit site reaching the epidural space.
Split into simpler sentences: The line carrying the drug may be threaded under the skin to emerge at the front of the patient, a process called tunneling. This is recommended with long term use so as to reduce the chance of any infection at the exit site reaching the epidural space.