“Minor surgery is surgery that happens to someone else” is an old medical joke. “Surgery is only minor if it happens to someone else” was mentioned as an “old joke” in 1981. It’s not known who originated the joke.
 
“A minor (car) accident is one that happens to someone else” is a similar saying that has been cited in print since at least the 1950s. “A recession is when your neighbor loses his job; a depression is when you lose your job” is a similarly themed expression.
 
   
Google Books
Transactions - National Safety Congress
Volume 1
Chicago, IL: National Safety Council
1956
Pg. 162:
“A good definition is that a minor accident is one that happens to someone else. To the man that has it, any accident is a major accident.”
 
9 February 1981, The Plain Dealer (Cleveland, OH), “2 knees are important to Tribe” by Terry Pluto, pg. 1-C, cols. 3-4:
“No matter what kind of injury, it is serious if it has to do with a knee,” Kuiper said. “It is like the old joke about minor surgery. Surgery is only minor if it happens to someone else.”
(Duane Kuiper of the Cleveland Indians.—ed.)
 
Google Books
Funny Business:
The Craft of Comedy Writing
By Sol Saks
Los Angeles, CA: Lone Eagle Pub. Co.
1991
Pg. 90:
(“Minor surgery,” someone — I’d bet it wasn’t a doctor — once said, “is surgery that happens to someone else.”)
 
Google Books
Living Longer and Other Sobering Possibilities
By Thomas James Mullen
Richmond, IN: Friends United Press
1996
Pg. 3:
Minor surgery is what is done to someone else. Major surgery is what happens to you.
 
Google Books
A Patient’s Guide to Knee and Hip Replacement:
Everything You Need to Know
By Irwin Silber
New York, NY: Fireside
1999
Pg. 109:
Many years ago I had “minor surgery” for a hernia that was performed with spinal anesthesia. That’s when I learned that “minor surgery” is defined as surgery that happens to someone else.
     
25 March 2001, Ashtabula (OH) Star Beacon, “Time for Wright to prove himself” by Terry Puto, pg. B3, col. 2:
But you know how surgery is—it’s only minor if it happens to someone else.
 
Google News Archive
30 April 2002, The Free Lance-Star (Fredericksburg, VA), “A painful lesson about pain” by Rob Hedelt, pg. C1, col. 1:
A day or two before the procedure, a good friend reminded me that the only minor surgery is one that happens to someone else.
 
Twitter
Dominic Hernandez
‏@stillsuperdom
I love when my doctor told me i’m gonna need “minor surgery”.. its always “minor surgery” if its happening to someone else
8:45 PM - 10 Oct 2012
 
Twitter
Tony Rapu
‏@drtonyrapu
”...Minor surgery is when they do the operation on someone else, not you”- Bill Walton. #DoctorsStrike pic.twitter.com/3vqhGx6315
10:09 AM - 4 Jul 2014
 
Providence (RI) Journal
Paul Ruggieri: Patients deserve a choice of surgeons
July 08, 2014 01:00 AM
(...)
As the old saying goes, minor surgery is what it’s called when it happens to somebody else. Patients deserve a choice. And a health insurance system that is explicitly cost designed to shovel patients toward potentially less experienced doctors is simply perverse.
Paul Ruggieri, M.D., of Providence, is a practicing general surgeon in Fall River and the author of the forthcoming book “The Cost of Cutting: A Surgeon Reveals the Truth Behind a Multibillion-Dollar Industry.”