Short Notes in Plastic Surgery

September 30, 2011

Treatment of Wounds – Repair and Reconstruction (Part 2)

Filed under: Chapter 15 — mthatte @ 4:18 am

1. Notwithstanding what has been said in the last paragraph of part 1 of this chapter there will be situations where a flap can save a life. example,
a. When a part of the brain bulges through a defect in the skull and is oedematous and does not have any skin or meningeal cover, the situation can lead to a serious infection followed by a fatal outcome. An oedematous brain is best not covered by anything rigid (bone or a metal mesh) and the situation demands a flap cover preferably from the adjacent scalp if available or by a free flap.
b. An exposed lung or heart with injuries to ribs with loss of skin and paradoxical respiration needs a flap cover after the ribs are stabilized. This restores the pleural space and averts further dire complications. A latissimus dorsi flap from the same side is a convenient option.

An example of a lateral chest wall defect including loss of bone treated with a local latissimus dorsi flap. This case is not traumatic in origin but the photographs are included because an identical post-traumatic situation will need a similar cover.

Photographs courtesy: Parag Sahasrabudhe from Pune.
c. After repair of major vessels for e.g. the carotids following gunshot wounds where the repair is done by direct suturing, vein grafts or a prosthetic graft but where the skin is shattered, contaminated and devitalized, a flap will help heal the vascular repair, restore circulation and reduce the overall chances of a blowout. A delto-pectoral flap can be a good choice for this site.
2. There will be situations where major post-surgical complications will threaten life or a repaired part. Here flaps can be of great help. examples,
a. A sternal dehiscence after a sternotomy for cardiac surgery can threaten life or mar the result of surgery. The condition of the patient permitting, a quick re-fixation of the sternum with resuturing of skin is the first option. But should the skin be suspect, its excision followed by a pectoralis major musculocutaneous flap based on a branch of the axillary artery away from the zone of sternal separation can avoid a catastrophe.

A. Infected sternal dehisons following open heart surgery. B. Debrided tissue including ends of ribs and cartilage. C. Indigenous VAC appliance has been applied. D. Pectoralis major flap can be seen moving in to the wound. Notice near the shoulder its attachment has been cut from the humerus yet preserving its blood supply which enters it about its middle. E. For the lower part of the defect the omentum has been brought up from the abdomen. F. The infected wound is now fully treated with vascularised tissue. G. Final result several weeks later. Skin has been sutured primarily.

Photographs courtesy: Parag Sahasrabudhe from Pune.

b. A repair of a major artery with a vein graft or a prosthetic graft as a planned procedure (for e.g. in the groin, thigh, popliteal fossa, neck or the axilla) can undergo an early or late complication because of infection and the skin might give way, become oedematous and unreliable. A local flap based on vessel or vessels arising proximal to the site of repair can secure the wound and give some chance for the vascular repair to succeed and save a limb. In the groin when the femoral artery is involved, a flap based on the deep inferior epigastric artery, a branch of the external iliac will be a good choice. As one goes lower down in the inferior extremity such flaps might become more difficult to find and release incisions on either side of the wound up to and into the fascia may allow a satisfactory closure of the wound.
c. When a major implant in the joint gets exposed post operatively, it’s only chance, if any, for any long term trouble free retention is if a flap is used to cover it quickly. Almost always, secondary suturing of such a wound will not help. Here too a local flap can be useful. For example, a gastrocnemius muscle flap for an exposed implant in the knee joint.
Comment: The plastic surgeon should be aware that most of the patients in this group may be on anti-coagulants.
3. With the advent of free flaps in patients who are stable and there is time to deliberate and time a flap, the choices have grown manifold. The old dictum that a local flap when feasible should be preferred over a distant flap (free or otherwise) now really holds true only in the area of the face and the scalp, because the nature of the facial skin with or without hair cannot be matched by any distant flap and in the scalp hair is of paramount importance. In both instances therefore the best use must be made of the available skin and this is where tissue expanders are most frequently used.
Comment: This is also the genesis of a full face transplant.
4. For other reasons for e.g. in reconstruction of the breast, the use of a latissimus dorsi flap or a lower abdominal flap based on the rectus muscle have been abandoned to a great extent because of scarring and the need to bolster the abdominal wall with a mesh where the rectus is used. Both flaps mentioned above are adjacent if not strictly local flaps. Instead the bulk of the lower abdomen together with the overlying skin based on major perforators of the inferior epigastric system are harvested as a free flap to reconstruct the breast.
5. Generally any local flap in the extremity means additional scarring in visible parts. Local flaps based on perforators are ingenious but patients might demand a free flap (could be based on a perforator) from a generally hidden part of the body.
6. In an athlete a local gastrocnemius flap for a tibial cover may not be fair to his future rehabilitation and his request for a distant free flap from a non-functioning area would then be legitimate.
Comment:
Microvascular free flaps are now being done routinely across specialities and the time may not be far when robots will be used for microvascular repair, such repairs might be done by technicians and lastly if a coronary vessel can be dilated and its patency maintained by a stent, surely such an innovation may be feasible in free flaps.
7. The introduction of free flaps has meant that more reliable, one stage sensate flaps can now be performed. While theoretically they should be better, at least from the point of view of protective sensations (if not finer sensory modalities), the jury is still out on what is the best treatment for e.g. in a denuded heel, the commonest site for which a sensate flap is used. Ideally the medial plantar flap (based on a branch of the posterior tibial artery and containing the medial plantar nerve) from the concavity of the middle third of the foot should be transposed to resurface the heel when such skin is available and when most of the soft tissue over the heel is missing and bone is exposed. But this might not always be possible. The choice is then between a staged cross leg flap, carrying the sural nerve, a free musculocutaneous flap, a free muscle flap covered with a skin graft or even a skin graft alone when a thin layer of viable soft tissue over the bone is nursed with careful dressing till granulation tissue appears. Long follow-ups with all the above methods have shown some success. The one common feature associated with all these flaps is hypertrophic cornification at the junction of the flap and the normal skin. This occurs very rarely with a medial plantar flap which remains the first choice if available. This cornified tissue needs to be carefully excised from time to time.
Comment: In the past a cross-finger flap was the commonest procedure performed for loss of skin and soft tissue in the fingers. They are not sensate flaps. Yet they almost never show any ulceration even in manual workers.
8. The choice particularly of a free flap certainly depends upon to a great extent on what flap the surgeon is most familiar with. Most surgeons will develop expertise with three or four types of flaps. Bulk is always an issue. Sometimes it is needed to fill a space or a cavity in the bone and at other times a bulky flap is avoided to prevent an ugly lump. On the subject of healing of infected cavities, though there have been papers on comparison of random pattern flaps and free muscle flaps in animals, showing the superiority of free muscle flaps; no human trials are available because they are not possible. In any event random flaps are now rarely done and it seems unlikely that a fasciocutaneous flap will have a dramatically lower blood flow than a muscle flap. Traditional anecdotal wisdom for whatever it is worth seems reluctant to divide flaps as superior or inferior in its healing power. A flap that succeeds fully is always a good flap and only good can come out of it.

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