In this day and age the most common type of surgery would probably be plastic surgery.
Dental
The most common form of facial surgery is to do with jaw correction surgery.
According to HowStuffWorks, liposuction is the most common cosmetic surgery as of 2005.
Poor hemostasis during surgery
Arthroscopy is the most common surgical alternative to knee revision surgery.
Cataract surgery is still the most common type of eye surgery and is also one of the most unnecessary. LASIK is currently number two and is becoming more common.
The most common type of plastic surgery on the jaw is corrective jaw surgery. This type of surgery is done to improve appearance, and the ability to chew better. This surgery is called Orthognathic surgery.
The most common complication of male to female surgery is narrowing of the new vagina. This can be corrected by dilation or using a portion of colon to form a vagina.
breast cancer surgery
Poetry
autobiography
All surgery carry risks regardless of the age/gender/condition of the patient. The most common risks of all surgery is infection and bleeding.