Complex sentence: During his procedure, he severs the ligaments in his victims' knees so they cannot stand and are forced to crawl, and connects the victims together in a line with their mouths surgically attached to the anus of the victim in front of them.
Split into simpler sentences: During his procedure, he severs the ligaments within his victims' knees to prevent leg extension, forcing his victims to crawl. He then connects his victims together in a straight line with their mouths surgically attached to the anus of the victim in front of them.