Provisionof Skin Cover
In the combined injury of skin and skeleton, skin damage can vary from minimal up to extensive degloving.
Where skin loss has been minor, but closure by direct suture can only be achieved under tension, a ‘relaxation incision’ is often recommended. The idea is that by making such an incision, tension will be reduced, and skin closure will be easier. The method sounds safe enough in theory, but it is less so in practice.
‘relaxing’ incision really creates a bipedicled flap which moves across to allow closure of the original wound. It is a well-recognised fact that even in optimal circumstances a bipedicled flap transferred in this way is an unsafe procedure and is liable to necrose. Used in a mixed skin and skeletal injury it is even more hazardous, for soft tissue damage and degloving have so often added their quota to the local devitalisation of skin.
The presence of degloving is a virtual contraindication to its use, and even in the absence of degloving the method should be used with the greatest of care. It is likely to be safest and most effective when closure is difficult because of local swelling of the limb from oedema and haemorrhage, rather than because of skin loss. The incision itself should be straight, placed at a considerable distance from the wound, and run in the long axis of the limb.
Undermining of the skin should be avoided.
When skin loss is more extensive, the replacement methods available are free skin graft, skin or fasciocutaneous flap, muscle or myocutaneous flap, and free flap -usually used individually, occasionally in combination.
Despite the alternative reconstructive methods
available today, split skin grafting should be the first choice if the raw surface is suitable.
In determining which surfaces are suitable for grafting, the key role of the periosteum has already been stressed. Excision of avascular tissue, fixation of the fracture, conservation of periosteum, closure of joint by suture of the capsule when possible, or cover with a muscle flap to create a graftable surface -all combine to give a graft the best chance to take.
The split skin graft has the great virtue also of being able on occasion to stabilise a clinical situation at minimal cost to the patient. It gives the surgeon a breathing space, and even if the graft is unsuitable as definitive cover it is possible to replace it at leisure once the patient’s condition has become stable.
Split skin grafting can be used in conjunction with other techniques.
A muscle flap, for example, may be needed to cover the bare bone element of a composite injury, but the graft can still be applied all around the area covered by the muscle as well as providing cover for the muscle itself.
Skin and fasciocutaneous flaps, rotation or
transposed, raised locally, have little if any place in acute injuries of this sort. Although safer when they include the fascia! layer, they have not been assessed objectively in the context of acute skin-bone trauma.
Before contemplating the use of a flap of this type, it would be essential to gauge the damage to the overall vascularity of the skin which it is proposed to use as the flap, particularly when an element of degloving is
involved. In any case the size and shape of the typical defect and the state of the surrounding skin would preclude its use.
The cross-leg flap may have been increased in safety by incorporating the fascial layer, but for the surgeon with little experience in its use (and such experience is becoming rarer as the method is losing popularity in other contexts) it must be regarded as distinctly hazardous. Such flaps have also to be used with particular circumspection, even as elective procedures in older patients, because of peripheral vascular problems in the ageing limb, and problems of joint stiffness.
These considerations would apply with redoubled force in an emergency situation, especially in the lower limb where the problem really arises. In a lower limb injury a cross-leg fasciocutaneous flap can be contemplated only by an experienced operator, in the young patient with unimpaired peripheral circulation and joints capable of tolerating the immobilisation -a combination of limitations likely to restrict its usage to near zero.
Local fasciocutaneous flaps being generally unsuitable for use at the acute stage of a combined skin-bone injury, the question arises whether the skin-fascia combination is capable of recovering sufficiently to be safe to use at a later date, and if so when. It is difficult to believe that degloved skin can recover to total circulatory normality, though it has been reported as being successfully used for subsequent reconstruction, which would suggest that at least a degree of recovery can take place.
The cautious surgeon is unlikely to accept this as a blanket finding. Reasoning from other clinical contexts, such observations as the amount of superficial scarring of the skin, its degree of comparative mobility, and the thickness of the layer of superficial fascia, would all play a part in decision making.
The use of muscle and myocutaneous flaps
raised locally would be confined to defects of the knee and upper half of the anterior tibia.
The medial head of gastrocnerhius is capable of covering the medial aspect of the knee joint and the upper third of the tibia.
Transfer is probably better carried out as a
muscle flap rather than as a myocutaneous flap when the option is present. Even used in late reconstruction the virtues of a muscle flap with grafting of its exposed surface, as compared with grafting of the secondary defect left by the transfer of the corresponding myocutaneous flap, have been recognised.
The potential hazard of the presence of muscle damage in assessing its usage in muscle transfer has already been discussed, and its unexpected tolerance of transfer as a flap even when showing signs of injury.
Where the necessary facilities and micro-vascular expertise have been available, free flaps, (fasciocutaneous, muscle and myocutane-ous), have been increasingly used in managing the more severe mixed injuries of skin and bone.
The techniques involved may be demanding, but the results, judged in terms of healing time, time to fracture union and time in hospital, are all better. Muscle, transferred as a flap, appears also to bring with it a degree of vascularity which, used to cover a surface which shows damage, prevents the damage progressing to necrosis, and it seems to retain these virtues even when it is part of a free flap.
In a situation where periosteal stripping and continuing exposure of bare cortical bone is so often followed by sequestration of its outer layer, this is a particularly valuable attribute. The muscle is also able to fill any bony defect which may have resulted from the removal of comminuted bony fragments judged to be avascular, and in this way eliminate dead space.
A free flap frequently used is the latissimus
Its long pedicle and reliable vessels of a good calibre make it among the less technically demanding transfers. The large area of muscle which can be transferred also makes it possible to cope with the more extensive defects successfully so that, even if part of the area of skin loss is graftable, it may still be convenient to cover the entire area with the flap. The rectus abdominis flap has become a popular, and equally suitable, alternative.
Both flaps tend to be used as muscle rather than as myocutaneous flaps, leaving skin cover to be provided by grafting.
For the smaller defect, alternatives are the radial forearm, the lateral upper arm flap and the
scapular flap. The comparative virtues of the three are discussed in Chapter 4.
The vessels at the fracture site chosen for anastomosis will depend on the site of injury and the extent of vascular involvement. They must be examined with extreme care for signs of damage, and interpositional vein grafts may be needed if it proves necessary to reach a healthy vessel wall which can be used for anastomosis. Immediately post-traumatic, reliable criteria of total normality of the vessel wall present a problem.
Seven to 10 days later, signs of damage to vessels are more obvious, with oedema and thickening of the wall.
The state of the other main arteries of the limb may also need to be assessed to ascertain to what extent the artery chosen for anastomosis is sustaining the limb alone or with minimal assistance from the other main arteries.
The findings may preclude the use of end-to-end anastomosis to the flap artery, and even in the absence of damage to other vessels end-to-side anastomosis may be preferable. The information provided by arteriography is, as already stressed (p. 102), only partial and must be matched against the findings at operation.
Fixation of the fracture is the responsibility of the orthopaedic surgeon, but in choosing the method he has also to ensure that his choice does not conflict with the needs of the soft tissue injury. The essence of the method used is that it should provide rigid fixation of the fracture, and the potential alternatives are plaster of Paris, with or without a window, internal fixation using plate and screws, intramedullary nail fixation and external fixation frame.
With plaster of Paris fixation there is no access to the area of skin loss unless a large window is cut. A window of adequate size is likely to affect fixation of the fracture adversely, and on these grounds is undesirable. However, if a window is to be avoided, the skin cover used at the time of primary treatment has to be restricted to split skin grafting at the very most, and it is therefore not an option where skin damage is a significant part of the total injury.
Even without a window, plaster of Paris fixation alone may not be considered capable of providing the rigid fixation regarded as essential when the fracture
Internal fixation using plates and screws may be an effective method in the closed tibial fracture but in the compound fracture with skin loss its role is more open to question.
The site of skin loss nearly always overlies the subcutaneous surface of the tibia, and addition of the incisions and dissection required to expose the bone to insert an anteriorly applied plate extends the area of soft tissue damage to an undesirable degree, in the surface where the tibia is most vulnerable from the point of view of overlying skin necrosis. Application of the plate to the posterior surface is an alternative, but the posterior approach has not become standard practice in this context.
In the comminuted fracture particularly, the
method is unlikely to be the one of choice, and even in the absence of comminution it has the serious disadvantage of adding considerably to the amount of bone exposed and soft tissue dissected.
Intramedullary nail fixation might appear to have adverse factors.
It might well be felt that the exposure of the entire medullary cavity to the surface, which the insertion of such a nail entails, would invite the spread of infection from end to end of the bone. The fact that it is being successfully used, admittedly in conjunction with the provision of well-vascularised flap cover, would indicate that this fear is largely
Viewed in relation to the provision of skin cover it has the considerable virtue that its use does not place any restraints on the method of providing skin cover selected by the plastic surgeon.
The external fixation frame also has the virtue of leaving the fracture site unimpeded from the point of view of providing skin cover.
The transfixion pins inserted into the bone at a distance from the fracture provide virtually absolute stability without interfering with the fracture site once the frame has been set up. The absence of interference with the soft tissues, damaged or undamaged, at or around the fracture site, allows the two components of the injury, bone and soft tissue, to be managed with minimal reference one to the other.
Almost the only aspect of the bony fixation which may affect soft tissue management is the site of insertion of the pins. This determines the line of the interconnecting bar, and thought should be given to this aspect to ensure that it does not make the reconstruction which the plastic surgeon wishes to use less easy technically, or even impossible. With this proviso, it leaves the entire range of reconstructive techniques available for use.
The fractures most often associated with skin loss involve the long bones, tibia and, much less frequently, ulna. Before the management of such an injury can usefully be discussed, it is necessary to have an understanding of the principles which underlie its treatment, for the detailed handling of the injury is the expression in practical terms of these principles.
A primary objective in treating such a combined injury is to prevent infection, and this is achieved by fixing the fracture and by providing skin cover to isolate it from the surface.
An X-ray of a fracture gives an incomplete
picture of the total injury in the way that it ignores the soft tissue element.
The severity of this latter element and the form it takes are of major importance when the soft tissues around the fracture site -muscle, fascia and skin -are being assessed for damage and even viability, or as potential sources to provide cover for the bone, fractured or merely bared by the injury.
The injury to muscle can take the form of obvious tearing of muscle fibres, but damage at a less gross level can also occur, resulting in swelling of the muscle belly.
Even so, muscle is unexpectedly resilient in practice, and has been successfully transferred in the form of a flap shortly after the original injury, though its use in this way is not without risk.
The injury to skin takes a different form, seen
most strikingly when part of the injury involves degloving of the skin and superficial fascia.
Degloving as an isolated injury has already been described, but when it is associated with bony trauma it has to be considered also in relation to the extent to which it might be possible to use degloved skin and its underlying layer of fascia as a local flap to cover the surface defect. Before the use of such skin can be considered, there would have to be clear evidence of circulation in the skin area, and even when this criterion has been fulfilled it has not proved a reliable flap source.
The various elements of a mixed skin-bone injury can vary widely in their severity, and the plastic surgeon is liable to have a biased view of the situation. He is likely to see only the injuries at the most severe end of the spectrum, and assume that they are the norm, whereas in fact the less severe injuries are being successfully managed by the orthopaedic surgeon on his own. Nonetheless, if a harmonious and effective relationship is to be built up, the plastic surgeon is best invited to see the patient at the acute stage if the orthopaedic surgeon considers that there is even a remote possibility that he may have to be involved in treatment later.
The greater trochanter is the projection which determines the site of the trochanteric ulcer. Initially, the main cavity of the ulcer is the trochanteric bursa which overlies the projection and, if this alone is involved, permanent closure may be achieved without interfering with the bone.
As the condition progresses the trochanter and neck of femur increasingly project into the cavity, and excision of trochanter and appropri-ate cortex of the shaft is required to let the soft tissues collapse and obliterate the cavity. In the most severe instances a pyoarthrosis of the hip joint may develop and, once present, this complica-tion is virtually impossible to eradicate without amputation of the limb.
The ulcer is so undermined in most cases that
free skin grafting is seldom practicable. Cover by a flap is necessary. When this takes the form of a skin flap a transposed flap is used; its precise situ-
ation and shape will depend on the size and shape of the ulcer, with the proviso always that the secondary defect should be on an area free from subsequent weightbearing.
Added safety can be provided by incorporating the iliotibial tract in the flap, in the form of a tensor fasciae latae myocutaneous flap.
The appropriate type of flap depends on the shape of the ulcer. Frequently suitable is the bilateral flap of buttock skin based on the in-ferior gluteal fold , and this double flap is especially useful in the sacral pressure sore in the non-paraplegic patient. If the shape and extent of the ulcer make this flap unsuitable, alternatives are the transposed or rotation flap using buttock skin, extending on to the lumbar region. Gluteus maximus has been incorporated into these flaps to add to their safety and effective-ness, and more recently flaps have been designed to use the gluteus maximus muscle in a more formal way.
Each muscle, together with a triangle of the overlying buttock skin, is detached from its sacral insertion and mobilised, preserving the inferior gluteal nerve and the gluteal vessels, and advanced to meet its fellow in the midline to reconstruct the postexcisional defect of the sacral ulcer, providing skin cover along with an underlying pad of muscle.
In using the glutei in this way there are several considerations which need to be taken into account, and which are not immediately appar-ent.
One concerns the fact that gluteus maximus is not an expendable muscle, and if the transfer will result in denervation it can only be used in the paraplegic patient. The advancement myocu-taneous flap as described should retain the nerve supply and can thus be used in the non-para-plegic. The entire area is also extremely vascular, and dissection involving gluteus maximus, indeed dissection generally in this area, both in the paraplegic and non-paraplegic patient, involves considerable blood loss.
Several techniques have been developed which do not fit readily into a neat classification, either because they are not strictly surgical, though they are used in a surgical context, or have been taken from other surgical disciplines because they offered a partial or complete solution to problems whose management by conventional plastic surgical methods was unsatisfactory.
TISSUE EXPANSIONIn this technique, a silastic ‘bag’, not unlike an uninflated balloon, is placed under the skin and superficial fascia, and inflated at intervals by the injection of saline under pressure. The saline is not injected directly into the ‘bag’, but into a small non-expansile reservoir placed at a distance from it, and connected to it by a fine bore tube.
In this technique, a silastic ‘bag’, not unlike an uninflated balloon, is placed under the skin and superficial fascia, and inflated at intervals by the injection of saline under pressure. The saline is not injected directly into the ‘bag’, but into a small non-expansile reservoir placed at a distance from it, and connected to it by a fine bore tube.
The effect of the inflation is to produce an increasing bulge of the overlying tissue, and in so doing stretch the skin. In this way the skin is ‘expanded’, increased in area, and made available for reconstruction. Expansion is exploited clinically in two ways.
In one, as used in postmastectomy breast recon-struction, the expanded skin and the underlying cavity are both utilised: the cavity for permanent insertion of a silicone implant to recreate the breast mound, the expanded skin to provide an envelope for the implant. . The other way in which the principle is used is in the creation of an area of skin availability which, sited alongside a defect, allows it to be closed directly.
The expanded area may be created beforehand, so that, when the defect is created, the expanded skin is already available to close it. Alternatively, it may be used to replace a skin graft, previously applied to cover the defect.
The skin adjoining a defect is generally re-cognised to give the best result in reconstructing it, because they have similar characteristics, and this is a major virtue of the method, one which shows most strikingly when it is used to extend hair-bearing scalp in replacing an area of alopecia. Various shapes of expanders are used -round, oval and crescentic -with different sizes, depending on the amount of expansion desired.
A skin incision is made, just long enough to allow the expander to be inserted without bending, and the pocket to accommodate it is dissected, generally at the deep level of the superficial fascia. A pocket is also made for the reservoir at a distance from the expander. 121 The reservoir is sometimes positioned externally, making injection easier as well as painless, though it probably increases the risk of infection reaching the expander.
A small volume of saline is injected immediately to smooth out the envelope of the expander, the incisions are closed, and the wounds left for 1-2 weeks to heal. Expansion is then begun, and repeated usually at weekly intervals. Whitening of the skin, indicative of local ischaemia, or a complaint of pain by the patient, are signs that expansion has gone far enough for the time being.
Over the period of the expansion, a degree of capsule formation usually builds up and, depending on its severity, it is left, scored or excised. The technique has its strong advocates, but overall it has not achieved the popularity which seemed likely when it was first introduced. Adverse factors concern the time taken to achieve adequate expansion, 6-12 weeks, and the increasingly bizarre appearance of the patient as expansion proceeds.
Even when circumstances are ideal, the complication rate is considerable, mainly the result of infection, haematoma or extrusion, and the nature of the technique means that any complication requires removal of the expander and spells failure of the method. The other substantial problem is that of designing the expansion, which involves three dimensions, to provide cover for a defect which, the breast and scalp apart, is usually two-dimensional. The most effective applications of the method have been where the surface is convex with a bony base, as in the scalp and forehead, and in breast reconstruction.
The flap, designed astride the intermuscular septum, is raised under tourniquet. Its breadth is limited to 6cm because of the need to close the secondary defect directly; its average length is 10 cm. As a first step, the line joining the lateral epicondyle and the deltoid insertion, representing the line of the intermuscular septum, is marked out on the skin.
Behind this line the flap contains no structures of note, and this makes it convenient to raise this seg-ment first, and establish the plane between the investing layer of fascia and triceps at the outset, dissecting forward until the lateral intermuscular septum is reached. The muscle fibres can then be separated from the septum over its full depth and over the length of the flap, exposing the vessels and the nerves in the septum.
The skin incision is extended proximally to just behind the posterior border of deltoid, and this allows the vessels and nerves to be dissected out proximally, separated from the radial nerve, and traced back into the spiral groove. In carry-ing out this dissection triceps and deltoid are separated, and any fibres of triceps attached to the septum which are obscuring the groove are divided.
With the vascular pedicle defined, the flap anterior to the septum can be freed from brachialis and brachioradialis, and its elevation completed. Throughout the dissection numerous small branches of the perfusing vessels supply-ing the surrounding muscles have to be divided.
When the transfer is as an osteofasciocutan-
eous flap, a strip of muscle is left attached to each side of the septum.
These strips, carried down to the bone over the length to be raised, provide protection for the vessels in the septum which are perfusing the two elements of the composite transfer, skin and bone. As a prelimin-ary to this part of the dissection the radial nerve should be retracted out of the way. A 1 cm broad, and up to 10 cm long, strip of the humeral shaft can be raised without compromising the strength of the bone. Clinical usage
The skin element is thin and the underlying layer of fat is generally thin, the combination making for a flexible flap. The scar which represents the sec-ondary defect, though in a site which may regularly be exposed, is not unduly obtrusive. The small-ness of the diameters of its perfusing vessels is its major drawback, the trend generally being towards flaps with larger perfusing vessel diameters.
The perforating system of the ulnar forearm flap passes from the ulnar vessels to the investing layer of fascia in the septum between flexor carpi ulnaris and flexor digitorum superficialis. The flap is generally sited towards the ulnar side of the forearm, but in other respects the techniques involved in its transfer are similar to those of the radial forearm flap in its fasciocutan-eous form.
The two flaps have a largely similar range of potential usage, but the radial form is more often used in clinical practice.
LATERALUPPER ARM FLAP
This fasciocutaneous flap is raised on the lateral aspect of the upper arm, just above the lateral epicondyle of the humerus, using as its vascular basis the posterior branch of the radial collateral artery and its venae comitantes. It can also be transferred as an osteofasciocutaneous flap by including a segment of the underlying humeral shaft. The parent vessel of the perfusion system is the profunda brachii artery.
This vessel runs alongside the radial nerve, deep to triceps, in the spiral groove, and reaches the lateral intermus-cular septum between triceps and the insertion of deltoid. There it divides into two branches, anterior and posterior. The anterior branch, small and not always present, accompanies the radial nerve as it passes distally in the groove between brachialis and brachioradialis.
The posterior branch, with an external diameter of 1.5-2 mm, is consistently present, with associated venae comitantes, running distally in the intermuscular septum between triceps and the brachialis-brachioradialis muscle group. In the intermuscular septum it gives off branches which reach the investing layer of deep fascia and the overlying skin.
Additional multiple small vessels pass from it into the surrounding muscles, and also reach the humeral periosteum to which the intermuscular septum is attached. The lower lateral cutaneous nerve of the arm supplies sensation to the skin area and is aviable for suture in the recipient area if a sensate flap is desired. Division of the nerve, and of the posterior cutaneous nerve of the fore-arm which arises in common with it, leaves an anaesthetic area distal to the flap site.
Cilantro has many health benefits. The leaves of this plant are delicate and lacy in appearance. It is an aromatic herb with wide range of uses. It is an aromatic herb when added to dishes, adds fantastic flavour, and it originates from Mediterranean countries. Cilantro is also known as coriander leaves, and has a pungent smell. It is widely used in Mexican, Indian and Thai dishes.
Health benefits of cilantro – Cilantro leaves are very low in calories and does not contain cholesterol. They contain antioxidants, fiber, vitamins and can lower LDL Cholesterol. The leaves and stem of cilantro are citrus in nature and has cleansing properties within the human body. When cilantro becomes part of diet, it can remove heavy metals from the body.
In ancient days, cilantro was used in perfumes. It was also used to remove the smell of raw meat. Besides these, cilantro leaves have disease fighting properties. When Cilantro leaves are used in dishes, the amount of salt can be reduced. This simply means that it can reduce the sodium intake.
Cilantro is also a rich in minerals like Potassium, Calcium, Manganese iron and magnesium. The potassium in it helps regulate heart rate and blood pressure. Manganese is used as a cofactor for the antioxidant enzyme, Superoxide Dismutase. Iron is essential for red blood cell production in the body. Therefore, it helps to prevent anaemia.
Besides minerals, Cilantro is also rich in many Vitamins. The Vitamins include Vitamin A, B complex and Vitamin C and Vitamin K. Vitamin C is a powerful antioxidant. Vitamin K helps to improve the bone structure. In patients with Alzheimer’s disease, it helps to reduce the amount of neuronal damage.
Heavy metals like mercury that can reach our body through various foods can be damaging to our body. Cilantro is one of the few herbs that can help eliminate heavy metals from the body.
This herb is also prevents kidney stone formation as it is a natural diuretic. When taken internally, Cilantro juice can reduce the amount of lipid peroxides in the body. Perhaps, that is one reason why Cilantro is an essential ingredient for body detox.
As an herb, this miracle leaf improves digestion in the body. It helps to keep the blood alkaline. Marinating alkalinity of the blood is important as our blood is slightly alkaline in nature. Cilantro also reduces eye disorders and macular degeneration.
The leaves of Cilantro help to improve digestion and detoxify liver. It is widely believed that the use of Cilantro in food reduces flatulence. Eating Cilantro improves the peristaltic movement through oesophagus.
Cilantro can be added to salads, stir fries and soups. Its seeds are typically dried and powdered and used in many dishes across the world. Make Cilantro part of your healthy diet and gain the numerous health benefits.
This flap, raised on the flexor aspect of the fore-arm, is perfused from the radial vessels. Their perforating branches supply the plexus of the investing layer of deep fascia, from which the blood is distributed to the overlying skin. The flap can be designed as a fasciocutaneous flap to transfer soft tissue alone, or in combination with a vascularised length of radial bone as an osteo-fasciocutaneous flap, and also transferring the fascia alone.
In the proximal part of the forearm, the radial vessels lie between the muscle bellies of brachioradialis and flexor carpi radialis, and their perforating branches reach the investing layer of fascia by passing along the intermuscu-lar septum between the two muscles. The tendons of the two muscles separate distal-ly, and the vessels become more superficial, lying on flexor pollicis longus and pronator quadratus.
The effect is to make the septum a less well-defined structure, but the concept of perforating branches from the vessels reaching the fascial layer remains valid.
In the part of the forearm between the sites of insertion of pronator teres and brachio-radialis the intermuscular septum, with its content of branches of the radial vessels, continues laterally over flexor pollicis longus towards the lateral surface of the radius.
There the bone, over a length of approxim-ately 10 cm, has a ‘bare’ area covered only by periosteum, with which the septum merges, its content of branches of the radial vessels forming a plexus on its surface, and supplying the underlying bone. Branches of the radial vessels also supply both the flexor pollicis longus and pronator quadratus muscles in addition to the flexor aspect of the radius from which they take origin, adjoining the ‘bare’ area.
The vessels passing superficially from the
radial artery to reach the investing layer of fascia provide the perfusion source for the fascio-cutaneous element of the flap; the vessels which continue laterally and deeply provide the vascular basis for the transfer of the segment of radius.
The fasciocutaneous element is generally constructed as an island and experience has shown that, provided there is an adequate breadth of the investing layer of tile deep fascia connecting the island to the intermuscular septum with its content of perforators and hence to tile radial vessels, it need not directly overlie the line of the vessels.
The geometry of the transfer largely governs its site. A distal site allows a long proximal vascular pedicle, useful when the transfer is as a free flap; a proximal site allows a long distal pedicle, valuable when a pedicled transfer to the hand is planned. When the transfer is pedicled, the radial vessels pro-vide the sole perfusion source; when a free flap is used, an additional superficial vein is gener-ally retained, available for anastomosis should the need arise.
The flap is raised under tourniquet. Its out-line, and the line of the radial vessels and a suitably sized superficial vein, generally the cephalic, are drawn out on the skin prior to exsanguination of the arm and inflation of the tourniquet. Fasciocutaneous flap
The plane of elevation lies between the investing layer of fascia and the muscles, and the key to the dissection lies in identifying the inter-muscular septum between brachioradialis and flexor carpi radialis. With these muscles and their tendons identified the septum is approached first from one side and then from the other, retracting the related structures to expose the radial vessels.
The vessels are mobilised along with the flap and the intermuscular septum, dividing the multiple small branches to the surrounding muscles. Care should be taken to avoid damage to the terminal branch of the radial nerve which is a close lateral relation of the radial artery in the middle third of the forearm.
Additional skin incisions are made, proxi-mally or distally as required, to allow further mobilisation of the vessels in creating the pedi-cle, and dissection free of the superficial vein. On the arterial side, the proximal limit is the origin of the anterior interosseous artery, which should be retained as a perfusion source for the distal forearm and hand; on the venous side, the proxi-mal limit is the antecubital venous plexus. Osteo(asciocutaneous flap
The skin island is raised as already described as far as the mobilisation of flexor carpi radialis and brachioradialis from the intermuscular septum. Retraction of the flap medially, and brachioradi-alis laterally, exposes flexor pollicis longus and pronator quadratus, and the vessels entering them.
An arbitrary line is drawn over the two muscles in the long axis of the radius between the insertions of pronator teres and brachioradi-alis, a length of approximately 10 cm, the line
along which the muscles and the underlying bone will be sectioned. Medial to this line the vessels entering the muscles are divided as the flap is mobilised, but the vessels entering the muscles lateral to the line and reaching the ‘bare’ area are carefully preserved.
The line is selected so that the radial shaft
is divided in a ratio of one-third lateral and two-thirds medial, the lateral element pro-viding the bony component of the composite transfer. Along the line, the muscles are incised down to the underlying bone and the bone is sectioned using a power saw with a fine blade. The segment of bone has also taken the form of a wedge, cut from the flexor surface of the bone or its lateral surface.
All three forms of resection appear to result in a vascularised segment, as long as the muscles, and the periosteum covering the bare area, are maintained.
Removal of a rectangle of bone leaves a point
of weakness at each end of the site of the resec-tion, and this can be reduced if an additional tri-angle of bone is removed so that the sharp edge at each extremity of the defect is rounded off.
Even so, a protective plaster of Paris is advisable for 4-6 weeks postoperatively while the radius remodels.
1. Fascia/ flap
Vascularised transfer of the investing layer of deep fascia on its own has also been carried out in the form of a segment separated from the overlying superficial fascia and skin. It provides
a vascularised sheet to reconstruct defects of the hand which has the virtues of thinness, and an ability to drape over an irregular surface, able to convert the defect into one capable of accepting a free skin graft.
Management of the secondary defect
The skin defect is split skin grafted. The defect almost invariably includes a considerable area of the visceral paratenon covering the tendon of flexor carpi radialis, and concentration on the raising of the flap is liable to divert the attention of the surgeon from the defect, allowing the paratenon to dry out. It must be kept constantly moist.
Adequate graft take and satisfactory hand function are of para-mount importance, and are achieved best by immobilisation in plaster of Paris. The hand should be immobilised in the position of func-tion with the wrist fully extended. This should be maintained for 14-21 days to ensure firm attachment of the graft before movements are allowed.
Fortunately, even if the graft fails, and an area of bare tendon is exposed, a final deficit in hand function is not inevitable.
With a conservative regime of patience and bland dressings, making sure that a full range of finger and wrist move-ments is maintained throughout, the exposed
tendon will be found to granulate slowly and heal spontaneously.
3. Clinical usage
Among free flaps, the radial forearm has an excellent safety record. It is technically easy to raise, and its popularity has added to this the virtue of familiarity. The skin which it provides is thin and pliable, capable of moulding to an irregular surface. Used as a fasciocutaneous flap, its only adverse factor of significance concerns the secondary defect, its appearance, and the potential for graft failure.
Now that the reason for graft failure is understood and can be coun-tered by maintaining an immobilised wrist until the graft is firmly attached, this is no longer an adverse factor. Used as a composite with bone, the perfusion sources spread along its length allow it to be osteotomised if necessary and, used to reconstruct mandible, this is an advant-age. The cross-sectional area available, however, is not great and it cannot withstand major stress.
As a consequence, it is not suitable for sub-sequent insertion of osseo-integrated implants.