The surgeon
如果文章是描述手术过程的，The Surgeon 应该就够了。在一台手术中，实际上只有一个SURGEON， 他就是主刀的其余的人全是助手。The 本身就有了限定或特指的含義。

You may consider adding Primary, major, main or leading etc, but such addition would make the phrase mean differently in English.



main surgeon

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Note added at 3 hrs (2016-01-29 16:06:41 GMT)
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I found the term of operating surgeon. Maybe you can use it but it is not a full match to the Chinese term of 主刀医师;

http://www.thefreedictionary.com/operating surgeon
In a statement to KUNA today, the operating surgeon, Dr.
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In addition, it is unlikely for the operating surgeon to have his or her usual operating team over the weekend which could slow down the surgery," explained lead author Dr.
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Now Catherine specialises in looking after patients undergoing hip and knee replacements at Hexham General Hospital and provides skilled assistance to the operating surgeon.
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6,7,9,10] The use of these agents and techniques is at the discretion of the operating surgeon and anesthesiologist.
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Due to movable and flexible tools, the operating surgeon can work in all parts of the abdominal cavity, even in the most remote and difficult-to-access areas.