In the 20th century a vast number of diagnostic and supportive techniques were developed, particularly in recent decades. Progress in the imaging of internal structures for diagnosis (see radiology) included the invention of computerized axial tomography (the CAT scan), magnetic resonance imaging, and a number of other methods. Computer technology made possible automatic chemical and cellular analyses of blood and other samples. Through the development of long, flexible tubes called endoscopes, surgeons are able both to see and to operate on deep-lying regions of the body with minimal trauma to the patient (see arthroscopic surgery and laparoscopic surgery). Surgeons also learned how to thread catheters through blood vessels into the heart, and they developed techniques such as balloon angioplasty to deal with the problem of arteries obstructed by atherosclerosis.
Advances in the ability to maintain vital body functions before, during, and after surgery were at least as dramatic. Support machinery developed for these purposes included the heart-lung machine, inhalation therapy devices, anesthesia machines, cardiac-monitoring devices, and cardiac defibrillators. The development of blood banks as resources for transfusions was also of major importance.
Surgical capabilities were also greatly widened by the introduction of the techniques of microsurgeryÑthat is, the use of magnifying systems and very precise tools to operate at the microscopic level. Using such methods, surgeons could reattach vessels and nerves of severed limbs, operate on the inner ear, remove tumors of the spinal cord, and other such operations once considered impossible. Through drug advances and other developments, surgeons also became increasingly able to transplant organs (see transplantation, organ) and to replace organs and other body structures with artificial organs.
Among other technologies adapted for surgical use are those of the laser and of ultrasonics. The laser's intense beam of light can be used as a cutting and cauterizing tool in many circumstances, and the focused pulses of sound waves from ultrasonic devices can be employed in diagnostic imaging and for breaking up kidney stones and gallstones.
With such expanding technical possibilities, the era when a surgeon might be expected to practice any type of operation has long since passed. Ten major divisions of modern surgery are recognized in the United States and Canada and, to a large extent, in the rest of the world. Some of these divisions have been in existence since the 19th century, especially in the great hospitals of the major cities of the world. These divisions include gynecology, which deals with the female genital organs and lower urinary tract; obstetrics, which is concerned with pregnancy and childbirth problems (and is now combined with gynecology as a single surgical division); ophthalmology, or the study and treatment of diseases of the eye; orthopedics, which deals with problems related to bones, joints, and related structures; otolaryngology, which treats diseases of the ear, nose, throat, and larynx; and urology, which deals with diseases of the urinary tract.
The other surgical divisions separated from the broad area of surgery in the 20th century. They include general surgery, which treats the digestive tract, abdominal organs, breasts, and endocrine glands, with subdivisions called pediatric surgery (surgery on infants and young children) and hand surgery; thoracic surgery, which deals with the chest wall, lungs, heart, and vessels and organs found in the chest; plastic surgery, which involves surgical repair of injuries or deformities; colon and rectal surgery; and neurological surgery, which deals with the entire nervous system, including the brain and spinal cord. For detailed information on these divisions of surgery, see medicine.
Each surgical division has its own accrediting board for the training of surgeons, and several of the boars have subspecialty fields with additional requirements. The accrediting agencies have mandated different training schedules for each division. A surgeon-to-be first obtains a medical license, following a program previously accepted by the Residency Review Committee for the specialty involved. At the end of training, the appropriate specialty board conducts an examination for certification. The surgeon must then become entitled to use the facilities of a given hospital. Each hospital has a series of committees that review all surgical cases, with an emphasis on cases with less than optimal results. The hospital is in turn regularly reviewed by the Joint Commission on the Accreditation of Hospitals. The quality of hospital-based practice is monitored in this complex, perhaps cumbersome manner to guarantee that a patient needing surgery will receive competent care by an adequately trained staff.