Indications & Considerations
When to Consider Microsurgery
When conventional options are not available
Surgical problems should be solved by the simplest and most dependable and expedient approach possible. Local tissue should be used before distant tissues, skin grafts before flaps, and reliable local flaps before transplants. With the improvement of microsurgical techniques, tissue survival has increased from 80% in the 70s to 95% in the early 80s. Survival of 98% to 100% is not unusual for certain transplants in the last few years. One can now use different criteria to formulate a reconstructive plan. The more complex or difficult procedures may be best in the long run from a functional and appearance standpoint, and will certainly reduce hospital stay, morbidity, and disability. The restoration of form and function is the ultimate goal of any reconstructive procedure, and the use of microsurgical transplantation and replantation has made this goal more obtainable. It is no longer necessary to create massive donor defects to provide critical coverage for vital structures.
When a tissue transplant can offer better coverage than a conventional flap
Expandable tissue can be brought in from a distance, revascularized to local vessels in the recipient area and augment the total and distant circulation. These transplants improve the area rather than surviving like parasites, as do conventional flaps. The extremely flexible and well vascularized muscle, covered with a skin graft and neurotized with motor or sensory nerves, can be used to fill dead space, cure osteomyelitis, and provide functional cover of "unlimited" size and shape.
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When to Consider Replantation
Individualization has become our overriding philosophy in replantation surgery. Some generally agreed upon indications and contraindications have been proposed by many, but this is a double-edged sword. The replantation opportunity appears only once for each severed part, and the decision to discard an amputated part must be individualized and not made to fit a rigid set of rules. A list of generally accepted indications and contraindications for upper extremity replantation appears below:
Indications
1. The thumb
2. All amputations in children
3. Multiple digits
4. The palm, wrist, and distal forearm levels
Contraindications
1. Concomitant life-threatening injury
2. Multiple segmental injuries in the amputated part
3. Extremely severe crush or avulsion
4. Extreme contamination, as in some farm injuries
5. Prior surgery or injury to the extremity that precludes replantation
6. Precluding systemic illness
7. Extremely prolonged warm ischemia
a) More than six hours for amputation levels proximal to the mid-forearm
b) More than 16 hours for more distal levels
It should be noted that the phrase "single digit amputation" does not appear on the above list of contraindications. A digit that has been completely amputated in a hand that has other significant non-amputation injuries may be a very important digit to replant, even though it is a single digit amputation. A single digit amputation distal to the insertion of the flexor digitorum superficialis tendon may afford a very gratifying replantation.
There is a considerable likelihood that the amputated digit replanted successfully will become a more useful finger in the hand.
An even more accepted contraindication to replantation in the past has been the ring avulsion injury. Although many indeed are not replanted, we continue to individualize our approach to these situations.
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What Types of Patients are Microsurgery Patients?
In our experience, 72% of all patients receiving microsurgical procedures received them for correction or closure of traumatic defects, 44% non-work related and 28% work related. Ninety-two percent of these have had previous surgery, so the microsurgical transplant or replant was a salvaging procedure.
Age and Gender
Transplants and replants are being performed on patients from age 1 to 86, with a two to one ratio of males to females. Survival rate does not seem to be related to age, sex, recipient site, or donor site.
Associated Conditions
Diabetics often appear with extremely difficult wound problems, which have responded without unusual complications. Recipient vessels in these individuals fortunately have skip areas that have provided windows for repair.
Previous pulmonary or cardiac disease is not necessarily a contraindication to microsurgery. In over 750 transplants and twice as many replants, we have encountered only one intraoperative coronary. The lack of systemic complication is largely because of the excellent anesthetic management during these long, complex operations and the support from our medical colleagues.
Anyone who is fit for surgery is a candidate for microsurgical transplant or replant.
Case example
An 86-year-old woman with severe cardiac problems received a gracilis transplant to her leg to close a malignant ulcer in lieu of an amputation.
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Donor Tissue & Site
The choice of the donor tissue is dictated by the size, location, and character of the recipient defect. With 33 donor areas available to choose from, this decision may seem challenging. The volume of the tissue needed rapidly narrows the field.
The donor defect deformity and disability must be considered. It does not make sense to borrow from Peter to pay Paul if you bankrupt Peter in the process. As reconstructive surgeons, we strive to preserve form while restoring function.
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Character of Wound
The type of wound is the next most important consideration. In general, infected wounds, acute or chronic, need the best vascular cover. Accordingly, muscles should be used because they are capable of covering irregular surfaces, obliterating dead space, and bringing antibiotics, white cells, and other factors important to wound healing.
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Postoperative Management
Although results continue to improve, no case can safely be called a success until 2 weeks postoperatively. The transplant or replant must be protected from trauma, dependency, cold, and tobacco and other drugs. The patients must be carefully counseled so that they realize their responsibilities. If a problem is suspected, it has probably already happened. One should therefore reoperate early if suspicion exists, because over 50% of initially failed replants and flaps can be salvaged.
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