SURGERY. The treatment of malformations and diseases by manual operation; secondarily, a medical practitioner's consulting room or office. Progress in the surgical art in the past century has in some measure run parallel with the advances made in all branches of science. The full development of methods for produc ing anaesthesia (q.v.) was the base upon which the progress and elaboration of surgery could be worked out. Study and improve ment in anaesthetic methods have continued to the present time and the results have brought within the sphere of operation con ditions which were previously beyond surgical aid.
Lister's discovery that a preventible bacterial infection was the cause of suppuration formed the next stage and upon it the development of modern surgery has been founded. By the em ployment of antiseptic and aseptic methods (q.v.) in the prepara tion of instruments, dressings and the patient's skin, it is now taken for granted that every operation will be carried out without the introduction of micro-organisms into the wound from without.
Advances in regard to these two controlling factors, anaesthesia and asepsis, during the past ten years have merely been develop ments of detail. Certain new substances have been employed as anaesthetics, both general and local, and minor improvements in apparatus and methods of administration have been introduced. As a theoretical basis for surgery the maintenance of asepsis in all procedures has been long accepted, and no material alterations have been brought forward. It must, however, be appreciated that asepsis is a relative term in regard to wounds of the body; micro-organisms in some numbers may be already present in the tissues, or are introduced despite every precaution. A more com plete appreciation of this fact has emphasised the importance of avoiding any treatment of the body tissues which will lower their natural resistance to such mild infection as may be present.
as that of carpentry; surgical judgment is only developed by long clinical experience and by the ability to learn from failure. In every major surgical operation the variable human factor is pres ent. It may affect the issue of medical and surgical procedures both on psychological and physical grounds, and an apprecia tion of these possibilities and an acceptance of the limitations of the individual's resistance must always be in the mind of the sur geon when planning an operation. The physical condition of the patient in respect of the function of all essential organs can be assessed with some accuracy by modern methods. His psychologi cal reaction is much less certain. In cases of operation for infec tive conditions the response to them of his natural defensive mechanism remains a factor of uncertainty. A good deal is known about the reaction of the body to bacterial infections (see IMMUNITY), but the problem of the artificial immunisation of the patient against them is still in its infancy. A consideration of these several problems on physiological lines has tended of late to divide operations for acute conditions into two or more stages.
It is perhaps in place here to mention pulmonary embolism. (see THROMBOSIS and EmBousm), a rare but serious complica tion of operations. It may follow a week or so after a simple surgical procedure which appears to have run a normal course. The condition is produced by the impaction of a clot of blood in one of the lung arteries. The clot originates in a vein in the opera tion area. The size of the clot and the corresponding area of the lung deprived of blood determine the severity of the symptoms.