The Clinical Picture
A precise picture of the condition is difficult to draw, for clinical generalisations do not necessarily apply to the individual case and the
condition itself is extremely variable and unpredictable. In the description which follows, the term keloid will be used to cover both conditions.
The tendency to develop keloids appears to diminish with age, but it is not possible in practice to forecast whether any particular patient will develop one.
Nevertheless, any incision in a known ‘keloid former’ is more likely to develop into a keloid than a similar incision in a random patient, and recurrence following simple excision of a keloid is highly probable. Keloids are much more common in the black than in the Asian patient, and more common in the Asian than in the white. The black patient also exhibits the condition in its most active form and the ‘tumours’ can on occasion reach quite grotesque proportions.
In the white patient, on the other hand, even the frank keloid does eventually become less active, and takes on the characteristics and activity rather of a hypertrophic scar.
Certain areas of the body have a particular
tendency to produce keloids ; the presternal area is probably the most prone of all and here oddly enough the shape of the keloid often shows a sex difference -in the male it tends to be irregular in outline, in the female the pull of the breasts commonly gives it a butterfly outline. The deltoid area is another notorious site, most often following BCG innoculation. The earlobe is the third common site, usually after ear piercing.
A scar may become keloid in only part of its length, a feature which shows particularly in the neck where the vertical scar is prone to keloid change while the horizontal scar is rarely affected. If a scar of the neck is excised incorporating Z-plasties it is not uncommon for the horizontal scars to be completely flat and soft, while the vertical limbs of the Zs show keloid or at very least hypertrophic change. In general, scars in lines of election show less tendency to keloid than those which cross them.
The surgeon is occasionally confronted with a large defect which requires reconstruction without delay, which will not accept a free skin graft, and for which, for technical reasons, no flap is suitable, whether skin, fasciocutaneous, muscle or myocutaneous, pedicled or free. The sites most likely to give rise to such a problem are the scalp and the anterior chest wall.
In the scalp area, the form the problem takes is how to provide cover as rapidly as possible for the defect with an extensive area of bare bone on the vault of the skull, and prevent it from progressing to sequestration of the outer table. In the chest wall, the problem concerns the extensive defect, usually from a combination of breast surgery and radiation, which is clearly incapable of granulating.
A possible solution in both situations may
be to cover the defect with a tissue which will produce granulations rapidly and effectively,
and provide a surface which will then accept a free skin graft. The omentum is such a tissue , and it has the additional virtue of being able to fill a dead space with extremely vascular tissue, of particular value when the space is chronically infected, or the result of radiation injury.
In preparing the omentum for transfer,
it is first freed from its avascular attachments to the transverse colon, leaving it attached along the greater curvature of the stomach. It is vascularised from branches of the epiploic vessels which form a series of loops in the direction of its free border.
For transfer as a pedicled flap, it is usually pedicled on the right gastro-epiploic vessels, the larger of the two, though either can be used, the branches to the stomach being divided to allow it to be mobilised. Its looped vascular pattern allows it to be lengthened without losing its vascula-rity, and the calibre of its vessels makes its transfer as a free flap technically straight-forward.
Used as a free flap, omentum can be transferred
to the scalp area, using the superficial temporal vessels for anastomosis.
Used as a pedicled flap, it can be used to cover
the anterior chest wall. It is harvested using a linea alba approach, leaving a gap in its upper end to allow its transfer.
Depending on the degree of adiposity of the
patient the omentum can either be a substantial structure containing a proportion of fat, or apparently insubstantial. Regardless of which form it takes, when spread over the defect and tacked to its margins, it produces granulations with remarkable speed, and accepts a split skin graft readily.
The use of omentum has obvious disadvan-
tages, with the need for a laparotomy, and the postoperative discomfort and degree of immobility of the patient which is inevitable. The amount of tissue the omentum can provide cannot be assessed preoperatively, nor can the effect on it of previous abdominal surgery. It is generally used only when every alternative has been considered and none has been found suitable.
In such a situation its ad-verse features have to be accepted.
When a scar, instead of becoming soft and pale in the usual manner, becomes red and thickened it is described as being either a hypertrophic scar or a keloid. These terms tend to be used rather indiscriminately, probably because it is difficult to define each with certainty.
The hypertrophic scar is raised above the level of the surrounding skin, rather red initially, but does not encroach on the surrounding normal skin, and shows an eventual tendency to regress spontaneously.
The keloid is a much more florid lesion, grossly elevated, tending to spread and involve the surrounding normal skin. Itching of the involved area is common, its severity matching the degree of activity, sometimes with hyperaesthesia and tenderness to touch. The tendency to spontaneous regression is much less in evidence.
These are the extremes and as such easily recognised, but in reality there is a gradation from the completely quiescent scar through the very mildly hypertrophic scar to the most severe of keloids, and the point at which a hypertrophic scar becomes a keloid is a matter of opinion. The gradation rather suggests that the arbitrary division into keloid and hypertrophic scar is artificial and that the conditions are really a single entity of varying severity.
The name is fortunately of subsidiary importance, for the treatment of both conditions is similar. Virtually nothing is known of the cause.
In treating the port wine stain type of haemangioma, the use of cover by cosmetics, and surgical removal, have been the unavoidable mainstays despite their manifest inadequacy, but the development of laser technology has now added a third therapeutic possibility. Two main types of laser are currently used, argon and tuneable dye lasers.
Both instruments work on the principle
that energy emitted by the laser is absorbed by the oxyhaemoglobin in erythrocytes within the ectatic vessels of the haemangioma. Diffusion of this energy damages the endothelial cells of the vessels and they undergo fibrosis. Circulation through the vessels ceases, and the port wine appearance is lost. With both types of laser, the end result of treatment is largely the same, but they reach it in different ways.
The argon laser emits blue-green light, with
most of the energy at 488 and 514 nm. Using a
1 mm laser beam spot, the dermis is penetrated to a depth of 0.75-1 mm. The energy of each pulse, though it is applied in very short pulses of 200 µs, tends to be dissipated beyond the blood vessels into surrounding tissues, giving rise on occasion to a degree of scarring. Focal alopecia can also occur.
The area of staining is treated in such a way as to produce a confluent patch, but up to 2 months have to be allowed so that the tissues can recover before treatment of a skin area adjacent to a previously treated site can be carried out.
The tuneable dye laser uses a rhodamine dye source, and emits light at 585 nm. Oxyhaemoglobin has an absorption peak at
577 nm, and the nearness of the two gives it the advantage over the argon laser of increased specificity, and penetration of the dermis to a greater depth, 1-1.5mm. As a result, the risk of scarring is low. In contrast to the argon laser, non-contiguous areas are treated with a 5 mm laser spot. This initially produces a purpuric patch of skin, which reverts to a normal skin colour within a fortnight.
Successive treatments are aimed at intervening residual areas of staining.
Regardless of which laser is used, multiple treatments are required at intervals of roughly
2 months to allow the tissues to recover. The comparative merits of the two types of laser are difficult to quantify.
Clinical experience suggests that the argon laser produces better results in dark port wine stains, while the tuneable dye laser is more effective in treating paler lesions, particularly in children.
In the older patient, the haemangioma tends to extend superficially, and in depth.
Superficial extension has the effect of creating increasing irregularity of its surface; extension deeply usually brings the lesion beyond the limit of penetration, and as a result it does not respond well to laser therapy.
‘Amateur’ tattoos, produced with Indian ink, have been found to respond well to treatment using the Q-switched ruby laser. Some, though not invariable, success has also been achieved
in treatment of traumatic tattooing. With 3 J at
694 nm delivered in a 30 ms pulse, with a spot size of 5 mm, the effect is confined to the carbon pigment, which is converted to colourless oxides. Carried out under local anaesthesia, the vasoconstriction of added adrenaline has the effect of minimising any interaction between the blood and the laser beam. Improvement has also been found to occur in dark professional tattoos.
The carbon component is removed, but unexpectedly significant fading of the red and green pigment has also occurred. This is felt to be the result of enhanced phagocytic activity, induced as part of the effect on the carbon component of the tattoo.
Laser technology is a rapidly expanding and
developing field in medical physics.
Protagonists claim considerable improvement in problem areas such as removal of hair (following flap transfer) and resolution of hypertrophic scars. These treatments remain to be proved in clinical practice and have not, as yet, been adopted widely.
Liposuction is a technique which permits ‘blind’ removal of subcutaneous fat through a small skin incision. Its most frequent clinical role is a cosmetic one, in the removal of unwanted subcutaneous fat as an element in ‘body sculp-turing’, but it also has a small place in routine plastic surgical practice, in removing large lipomas and defatting unduly bulky skin flaps to make them conform to the surrounding contour after completion of their transfer.
It allows a large area to be defatted through a small skin incision, reducing scarring and simplifying postoperative care. Depending on whether the procedure is being carried out under local or general anaesthesia, the fat to be aspir-ated is infiltrated with a local anaesthetic agent or saline, containing adrenaline in low concen-tration. This facilitates aspiration and helps in achieving haemostasis.
A small skin incision is made, and the suction cannula is inserted into the subcutaneous layer in the area to be aspirated and attached to a high-pressure suction pump. It is then moved to and fro like a piston, directed radially from the site of insertion through an arc. The cannula is blunt ended, and in its to and fro movements it disrupts the fat, which is sucked out into the suction pump reservoir, the blood vessels traversing the area largely escaping damage.
It is important that the suction should not be applied, either superficially as far as the deep surface of the dermis which results in a lumpy skin surface, or deeply as far as the deep fascia! layer which creates an area of adhesion of the skin. With suction completed, a pressure dressing is applied to the site. Local bruising can be considerable, but infective complications are infrequent.
Lipomas with little or no fibrous tissue are readily treated by this technique, but those with a more extensive fibrous stroma are difficult to remove, and may require formal excision. The flaps which benefit from debulking tend to be from the groin or hypogastrium, and although it is suggested that fat does not reaccumulate after removal, flaps from those sites are notorious for redeveloping subcutaneous fat if the patient puts on weight. When this occurs, the procedure may have to be repeated.
On occasion when planning reconstruction it is clear from the outset that the intended free flap lacks the pedicle length to reach adequate, healthy receptor vessels. This deficiency may not be apparent until the pro-cedure is underway.
Whether no alternative reconstruction is possible or whether past the point of no return, this shortfall, due to an inher-ently or unexpectedly short flap pedicle or due to fibrosis of receptor vessels resulting from trauma or irradiation, can be overcome by use of vein grafts. Sections of superficial vein from the limbs -basilic or cephalic in the arm, short or long saphenous in the leg -can be harvested and inserted between receptor and flap vessels as a vascular conduit to restore a circulation.
Care is required to select a vessel of suitable calibre to provide a reasonable match for the vessels to which the graft is to be anastomosed. Harvest of the vein graft should be atraumatic, with careful bipolar coagulation or ligation of side branches. The length and axial orientation need to be accurate when it is inserted into the defect. Most importantly the direction must be adjusted to take account of the valves in the vein graft.
Consequently, the graft must be reversed before insertion into the arterial side of the circulation, and be orientated nor-mally for bridging the venous deficit. Con-siderable dilatation of vein grafts bridging arterial defects is the norm. This creates a tendency to turbulent flow and, because there are four rather than two anastomoses, the vascular com-plication rate due to thrombosis tends to be high-er than usual.
The technique of microvascular suture is unaltered and each anastomosis can be end-to-end or end-to-side as local circumstances dictate.
The sequence in which the sutures are placed may vary, but the same technique is used for each individual suture. For end-to-end anastomosis, a suture is inserted at each end of the opening. The back wall is then sutured, followed by the front wall. For end-to-side anastomosis, the triangulation technique classically described by Carrel is stan-dard.
The technique involves the insertion of three key sutures at equal distances around the circumference of the line of the anastomosis, the intervening gaps being filled in with additional sutures. The first two of the key sutures are inserted 120° apart, and the additional sutures inserted between.
The vessels are turned over, and the third key suture is placed in the middle of the back wall equidistant from the first two. The intervening gaps are then closed. The distance between indi-vidual sutures should be such that the vessel ends are completely apposed leaving no holes between, through which blood can escape. The sequence in which the vessels are anasto- mosed is to some extent a matter of personal preference, and is often dictated by the circumstances in the individual case.
If one ves-sel lies deep to the other, the deeper anastomosis should be completed first. In carrying out vessel anastomoses, a problem which the surgeon faces is what to do with the needle while the instrumental tying of each suture is being carried out. It is essential that it should be kept visible in the field, ready to be picked up when the ends of the completed knot are cut. A solution is to insert its tip into the gauze swab usually in the field , present to soak up excess irrigation fluid. When both anastomoses, arterial and venous, are completed the circulation is restored by removing the microclamps, starting with the clamp distal to the venous anastomosis, working back against the direction of flow, and finishing with the clamp proximal to the arterial anasto-mosis.
The clamp distal to any anastomosis in the direction of flow should always be removedfirst, other» wise the build-up of pressure is liable to result in leakage of blood from the anastomosis, and thrombosis may result. When the clamps are opened, and blood passes across the anastomosis there may be a little bleeding from between sutures, but this subsides quickly. An obvious source of leakage calls for additional sutures.
It may take a few moments for the flap to become pink, and the first sign of circulation is often filling of the vein. At first, flow may be sluggish, but it usually picks up quickly. A bounding, pulsatile artery, a pink flap, and a full vein are signs of a healthy, satisfactory circulation. If this is not rapidly forthcoming, the cause must be sought.
Arterial spasm can be corrected by topical application of a dilating agent such as local anaesthetic or papaverine, but if this fails it is better to take down or resect the anastomosis and refashion it. Expectant management merely postpones the inevitable. The same applies to venous problems.
Test for patency
If doubt exists, patency can be tested by occlud-ing the vessel distal to the anastomosis with two microforceps placed side by side. Blood is milked distally by the distal forceps leaving an empty portion of vessel.
The proximal forceps are opened and, if the empty portion fills, it means that the anastomosis is patent. With the anastomoses complete and function-ing, the vessels usually take up a ‘natural posi-tion’ in which they curve or loop gently, but the surgeon must also see that there is no kinking or compression. The final step in the procedure is the insertion of a drain under the flap.
If suction drainage is being used it should be applied at a distance from the site of the anastomosis, prefer-ably fixed in position by using a transfixing suture through drain and skin.