however的用法,为什么老是放在句中,用两个逗号与前后句隔开,例句如下

however的用法,为什么老是放在句中,用两个逗号与前后句隔开,例句如下
Appendicitis is potentially fatal; consequently,patients with symptoms strongly suggesting appendicitis almost always have their appendix removed.The appropriate surgery is low-risk but performed unnecessarily in about 20 percent of all cases.A newly developed internal scan for appendicitis is highly accurate,producing two misdiagnoses for every 98 correct diagnoses.（Clearly,using this test,doctors can largely avoid unnecessary removals of the appendix without,however,performing any fewer necessary ones than before,）since .
（Clearly,using this test,doctors can largely avoid unnecessary removals of the appendix without,however,performing any fewer necessary ones than before,）since .这一段应该如何翻译,竟然直接从without这里断开了,应该怎么翻译呢?
应该是从半路翻译呢,但是没有,
还是应该从头翻译,但是医生,
还有这里any fewer necessary