That branch of medicine involved in the treatment of injuries, deformities or individual diseases by operation or manipulation. It incorporates: general surgery; specialised techniques such as CRYOSURGERY, MICROSURGERY, MINIMALLY INVASIVE SURGERY (MIS), or minimal access (keyhole) surgery, and stereotactic surgery (see STEREOTAXIS); and surgery associated with the main specialties, especially cardiothoracic surgery, gastroenterology, GYNAECOLOGY, NEUROLOGY, OBSTETRICS, ONCOLOGY, OPHTHALMOLOGY, ORTHOPAEDICS, TRANSPLANTATION surgery, RECONSTRUCTIVE (PLASTIC) SURGERY, and UROLOGY. Remotely controlled surgery using televisual and robotic techniques is also being developed.

Surgery is carried out in specially designed operating theatres. Many patients are now treated as day patients, often under local anaesthesia, being admitted in the morning and discharged later in the day.

More complex surgery, such as transplantation and neurosurgery, usually necessitates patients being nursed post-operatively in high-dependency units (see INTENSIVE THERAPY UNIT (ITU)) before being transferred to ordinary recovery wards. Successful surgery requires close co-operation between surgeons, physicians and radiologists as well as anaesthetists (see ANAESTHESIA), whose sophisticated techniques enable surgeons to undertake long and complex operations that were unthinkable 30 years ago. Surgical treatment of cancers is usually done in collaboration with oncologists. Successful surgery is also dependent on the skills of supporting staff comprising nurses and operating-theatre technicians and the availability of up-to-date facilities and equipment.

A separate meaning is that of the clinic or consulting rooms of a general practitioner.