Diathermy is a therapeutic treatment in which heat is produced in body tissues by passing high- frequency electric currents through them. Research Diathermy
Endoscopy is the examination of internal parts of the body using special instruments known as endoscopes. The simplest method of instrumental examination is that employed for the analcanal and rectum. A 'speculum' (proctoscope) which is in fact a simple tube with a handle, is introduced through the analcanal and the surgeon examines the rectal wall through the tube. To facilitate the introduction of the instrument, there is a shaped conical stopper which is known as the 'obturator.' This same principle of a shaped introducer is used on many instruments which have an open tubular end. Sigmoidoscopy is the examination of the upper regions of the rectum and the sigmoid or pelvic colon with a longer tubular speculum. Because the folds of mucousmembrane fall against the end of the instrument and obstruct the view, air inflation is used for the introduction of the sigmoidoscope so that the lumen of the bowel is distended. The surgeon inserts the instrument under direct vision, inspecting the wall of the bowel as far as 25 cm. from the anus.
The oesophagoscope is a similar instrument passed down the oesophagus through the mouth, thus enabling the surgeon to inspect the whole length of the gullet. The inside of the stomach is examined by the gastroscope, using air inflation. Through a very small incision in the abdominal wall the surgeon may introduce another viewing instrument, the peritoneoscope, and with this he may inspect the inside of the peritoneal cavity and obtain infonnation to enable him to reach a decision without open operation. In order to separate the coils of intestine from one another and allow the satisfactory inspection of the viscera, the peritoneal cavity is inflated with air through a separate cannula. Endoscopic instruments, except for the simpler forms of proctoscope, carry their own miniature lamps which draw electric current either from a battery or the mains through a transformer to reduce the voltage. The bladder and urethra are inspected with the cytoscope and urethroscope. The urinary tract is distended with water instead of air for the inspection, but air inflation is sometimes used for the lower part of the urethra. Various forms of speculum are used for the vagina and these are usually illuminated by direct light, although some forms carry a lamp of their own. Operations for the removal of tissue for microscopic examination (biopsy) are performed through some of the tubular instruments, and for this purpose there are special long forceps and diathermy electrodes. Examinations carried out with endoscopic instruments may be made with local or general anaesthesia and in the case of the rectum and colon, without anaesthesia. Research Endoscopy
There are several methods of controlling bleeding during surgical operations. 1. When an incision is made, much of the bleeding comes from the skin edges and from subcutaneous tissue: small towels are often used, clipped to the edges of the wound to protect the cut surface, and prevent the repeated rubbing away of clot which would otherwise occur. These are called variously 'side-towels','skin towels' or 'tetra towels'. The latter term arose as these towels are commonly attached with four- pronged forceps ('tetra forceps'). 2. By pressure. As the surgeon makes his incision, he or his assistant applies a gauze swab to the raw area. Capillary and most venous bleeding stops almost immediately, and does not re-start unless the surface is rubbed. 3. Pressure forceps (arteryforceps) are applied to the cut ends of arteries, as little of the surrounding tissue as possible being included in the jaws of the forceps.
These bleeding points are dealt with at some later stage in the operation in one of four ways. (i) The arteryforceps are simply removed. Bleeding does not recur as the crushed end of the vessel has sealed itself off. (ii) Surgical diathermy current is applied to the pressure forceps, thus coagulating the end of the blood vessel. (iii) A surgical ligature is tied round the tissue included in the forceps which are then removed. (iv) A stitch is inserted and tied round the tissue held in the forceps in order to secure more firmly the end of the cut vessel. 4. The surgical diathermy is used to make the incision through the muscle and deep tissue layers. This technique is used especially in the treatment of cancer and particularly in the removal of vascular structures such as the breast. Small blood vessels are thus sealed as the tissue is divided. 5. The application of gauze soaked in adrenaline solution. This drug constricts the ends of the vessels and is particularly useful in the nose.
Where extensive bleeding may be expected - such as in plastic operations on the face - the operation area is sometimes infiltrated with a saline solution of adrenaline. By the time the effect of the adrenaline has passed off, the divided vessels have become blocked by clots. 6. The application of hot packs. The combination of pressure and heat speeds the clotting process and the retraction of the cut ends of vessels. 7. Thromboplastin released by enzymes from damaged tissue is essential to start the clotting process. There is very little damage in a clean surgical incision and thromboplastin formation can be brought about by the surgeon taking a small piece of muscle, and pulping it by repeated crushing with pressure forceps. This ' muscle graft' is applied to the bleeding area. Purified thrombin is supplied in powder in sterile ampoules ready to mix with sterile water: the solution is then applied with a swab or a spray and is particularly useful under skin grafts where it acts as a kind of glue. Fibrin foam is another preparation used extensively in neurosurgery where even a small amount of bleeding into the brain or nerve, may do irreparable damage. Gelatin 'sponge' supplied in small biscuit-like strips, can be used in bleeding cavities or tied to the surface of a bleeding organ. The sponge acts as an artificial network in which clotting occurs and the substance is itself absorbed.
Oxycel (oxidised cellulose) acts in a similar way and promotes rapid clotting. It is used in such sites as the prostatic cavity and can be tied around the catheter which is left in place at the end of operation. Calciumalginate is a similar preparation and is manufactured from sea-weed. The raw oozing surface is moistened with one solution which is then activated by spraying with a second solution containing calcium. All these artificial coagulants are only of use for 'low pressure' bleeding - that is from capillaries or small veins. Research Surgical Haemostasis
The Probert Encyclopaedia was designed, edited and programed by
Matt and Leela Probert
Abbreviations
Research Diathermy
