Alexis Thomson

“ A successful graft of living tissue is not only capable of regeneration, but it acquires a system of lymph and blood vessels, so that in time it bleeds when cut into, and is permeated by new nerve fibres spreading in from the periphery towards the centre. ”

“ The process of repair in living tissue depends upon an inherent power possessed by vital cells of reacting to the irritation caused by injury or disease. The cells of the damaged tissues, under the influence of this irritation, undergo certain proliferative changes, which are designed to restore the normal structure and configuration of the part. ”

“ The dressing and the after-treatment are the same as in epidermis grafting.
There is a degree of uncertainty about the graft retaining its vitality long enough to permit of its deriving the necessary nourishment from its new surroundings; in a certain number of cases the flap dies and is thrown off as a slough--moist or dry according to the presence or absence of septic infection.
The technique for cutis-grafting must be without a flaw, and the asepsis absolute; there must not only be a complete absence of movement, but there must be no traction on the flap that will endanger its blood supply. ”

“ Any given tissue can be replaced only by tissue of a similar kind, and in a damaged part each element takes its share in the reparative process by producing new material which approximates more or less closely to the normal according to the recuperative capacity of the particular tissue. The normal process of repair may be interfered with by various extraneous agencies, the most important of which are infection by disease-producing micro-organisms, the presence of foreign substances, undue movement of the affected part, and improper applications and dressings. ”

“ In the course of a few days this clot becomes permeated by granulation tissue, the fibroblasts of which are derived from the sheath of the tendon, the surrounding connective tissue, and probably also from the divided ends of the tendon itself. These fibroblasts ultimately develop into typical tendon cells, and the fibres which they form constitute the new tendon fibres. Under aseptic conditions repair is complete in from two to three weeks. In the course of the reparative process the tendon and its sheath may become adherent, which leads to impaired movement and stiffness. ”

“ The epithelium of a mucous membrane is regenerated in the same way as that on a cutaneous surface.
Epithelial cells have the power of living for some time after being separated from their normal surroundings, and of growing again when once more placed in favourable circumstances. On this fact the practice of skin grafting is based (p. 11) .
_Cartilage._--When an articular cartilage is divided by incision or by being implicated in a fracture involving the articular end of a bone, it is repaired by ordinary cicatricial fibrous tissue derived from the proliferating cells of the perichondrium. ”

“ If the ends of a divided striped muscle are at once brought into apposition by stitches, primary union takes place with a minimum of intervening fibrous tissue. The nuclei of the muscle fibres in close proximity to this young cicatricial tissue proliferate, and a few new muscle fibres may be developed, but any gross loss of muscular tissue is replaced by a fibrous cicatrix. It would appear that portions of muscle transplanted from animals to fill up gaps in human muscle are similarly replaced by fibrous tissue. ”

“ Healing is more rapid when the edges are in contact, when there is a minimum amount of blood-clot between them, when the patient is in normal health and the vitality of the tissues has not been impaired. ”

“ It is instructive to associate the period of survival of the different tissues of the body after death, with their capacity of being used for grafting purposes; the higher tissues such as those of the central nervous system and highly specialised glandular tissues like those of the kidney lose their vitality quickly after death and are therefore useless for grafting ”

“ To apply his art intelligently and successfully, it is essential that the surgeon should be conversant not only with the normal anatomy and physiology of the body and with the various pathological conditions to which it is liable, but also with the nature of the process by which repair of injured or diseased tissues is effected. ”

“ Capillary loops grow into the coagulum, and migrated leucocytes from the adjacent blood vessels destroy the red corpuscles, and are in turn disposed of by the developing fibroblasts, which by their growth and proliferation fill up the gap with young connective tissue. It will be evident that this process only differs from healing by primary union in the _amount_ of blood-clot that is present. ”

“ REPAIR IN INDIVIDUAL TISSUES
_Skin and Connective Tissue._--The mode of regeneration of these tissues under aseptic conditions has already been described as the type of ideal repair. In highly vascular parts, such as the face, the reparative process goes on with great rapidity, and even extensive wounds may be firmly united in from three to five days. Where the anastomosis is less free the process is more prolonged. The more highly organised elements of the skin, such as the hair follicles, the sweat and sebaceous glands, are imperfectly reproduced ”

“ Wounds heal slightly more quickly in the young than in the old, although the difference is so small that it can only be demonstrated by the most careful observations.
Certain tissues take longer to heal than others: for example, a fracture of one of the larger long bones takes about six weeks to unite, and divided nerve trunks take much longer--about a year. ”

“ With undermining it is usually easy to bring the edges of the gap in the abdominal wall together, even in children; the skin flap on the dorsum of the hand appears rather thick and prominent--almost like the pad of a boxing-glove--for some time, but the restoration of function in the capacity to flex the fingers is gratifying in the extreme.
[Illustration: FIG. 1.--Ulcer of back of Hand covered by flap of skin raised from anterior abdominal wall. The lateral edges of the flap are divided after the graft has adhered.] ”

“ Wounds of certain parts of the body heal more quickly than others: those of the scalp, face, and neck, for example, heal more quickly than those over the buttock or sacrum, probably because of their greater vascularity. ”

“ By carrying out movements between the constituent parts, the fibrous tissue covering the ends of the bones becomes moulded into shape, its cells take on the characters of cartilage cells, and, forming a matrix, so develop a new cartilage. ”

“ The Blood# lends itself in an ideal manner to transplantation, or, as it has long been called, _transfusion_. Being always a homoplastic transfer, the new blood is not always tolerated by the old, in which case biochemical changes occur, resulting in haemolysis, which corresponds to the disintegration of other unsuccessful homoplastic grafts. ”

“ The cutting is made easier if the skin is well stretched and kept flat and perfectly steady, the operator's left hand exerting traction on the skin behind, the hands of the assistant on the skin in front, one above and the other below the seat of operation. ”