This article is to review the role of microsurgery in facial trauma reconstruction. Microsurgery was developed since 1960s and had been applied on facial trauma from 1970s to treat amputated scalp, nose, ear and lip. Microsurgical replantation of scalp and small parts of face restores function and achieves aesthetic results, but small size of vessels and venous drainage problems are most technical challenging. In this article, we reviewed many talented authors’ work to solve those problems in facial tissue replantation. If defects are huge, we need microsurgical free flaps for reconstruction. The current workhorse is anterolateral thigh flap and we reviewed the versatility and new concepts of the flap. Development of perforator flaps was another milestone of flap reconstruction because of better cosmetic result and lower donor site morbidity. We reviewed the concepts, history and application of perforator flaps. Finally, facial replantation developed in recent 5 years to treat extremely large facial defects which cannot be reconstructed with microsurgical flaps and traditional flaps alone. The task is complex and needs a large team to support the whole procedure. We also reviewed the facial allotransplantation, which is the ultimate application of microsurgery in facial trauma reconstruction.
Trauma, tumor, cancer ablation and burn all result in facial tissue loss and deformity. The traditional reconstructive ladder-direct closure, skin grafts, local flaps, distant flaps, free flaps—still applies to reconstruction of the face as in any area of the human body [
Amputation of scalp, ear, nose or lip is not common. The results of using the composite graft technique to replant these parts are not predictable and complete failure is very common [2,3]. Because there is nothing superior to the original tissue with satisfactory functional and aesthetic results, microsurgical replantation of the amputated scalp and small facial parts (ear, nose and lip) should always be attempted first [4,5]. When suitable donor and recipient vessels are available, replantation of any severed tissue may be successful. However, replantation of these body parts remains technically challenging because the arteries and veins encountered are extremely small and lack of suitable veins for drainage is common [6,7]. All efforts should be made to repair these injuries microsurgically, because it currently offers the best reconstructive solution and yields a more reliable outcome [4, 5,8-10].
The first successful replantation started from an arm amputation four decades ago [
Decreasing warm ischemia time, aggressive debridement and good vascularization of the tissue by microvascular anastomosis are the fundamental principles to gain favorable results. Artery repair requires 10-O to 11-O Nylon and delicate microsurgical technique. Vein grafts are usually needed to bridge artery or vein defects due to avulsion, vessel stump loss after debridement and for tensionless closure [16-18]. An absence of venous outflow in small part replantation often results in complete failure [
Scalping injuries are rare. One-stage successful replantation of a partial or total avulsed scalp by microvascular anastomosis offers a superior result to any other types of reconstruction and provides substantial economic, social, and psychological benefits [29,30]. Every effort should be made to save the avulsed scalp, even in severely damaged and juvenile cases [31,32]. The success rate was 90 percent [33,34] and skillful and experienced surgeon had more favorable outcome [
The commonly used arteries are temporal artery and occipital artery. The temporal artery has reasonable size and thus is used primarily [34,35]. Occipital artery is an option [36,37] but the anatomic position is not as convenient as superficial temporal artery due to possible coexisting cervical spine injury [
A good venous return would be more important for a successful replantation than the number of vessels anastomosed [
Despite the 90 - 95 percent success rate, partial loss of the tissue is fairly common about 30 percent of the replanted tissue [17,18,37,49]. Additional revision of replanted tissue is frequently needed [
Nerve repair is not easy in scalp replantation due to avulsion [
The ear, nose, and lip protrude outward from the face, thus making them readily injured by trauma. These injuries occur due to animal bites (dogs [
The primary arterial supply to the ear is from branches of superficial temporal artery at about the level of the tragus. Superficial temporal artery and posterior auricular artery can be used for ear replantation [
Arterial anastomosis in the amputated lip is by the labial artery [56,60,66]. In nasal replantation, labial artery, the left nasal branch of the facial artery and the right nasal branch of the left supratrochlear artery [
Like scalp replantation, the real problem with small part replantation is the venous drainage. The veins on the posterior ear surface are extremely small and are few in number. Transillumination to the amputated ear might show veins in young children ear replantation [
It is important to know adjunctive reconstructive techniques in order to salvage amputated cartilage when vascular repair is impossible or fail or partial necrosis occurs. The ear cartilage can be salvaged by wrapping it in the temporoparietal fascia [5,80]. The nasolabial flap was used to provide coverage of nasal alae when partial loss of the replant occurred after microvascular replantation [
The success rate is difficult to estimate due to relatively few reports. The largest reported series from 12 institutions contains only 13 patients who required lip replantation [
A 30-year follow-up of the first ear replantation by Pennington et al. showed long-term superior aesthetic quality and durability result. The degree of minor aesthetic change in shape depends on the extent of original injury, and proportion of the amount of tissue loss. Generally, cartilage atrophy didn’t occur and the stability was not affected if there is little cartilage loss but the size and shape might be changed due to conchal distortion and scar contracture. Sensory recovery is complete within 3 years and canal stenosis is preventable with a silicone stent for 3 months [
The patient after lip replantation regained sensation and motor function even though no motor nerve and sensory nerve were repaired. Electromyography showed almost normal vermilion muscle motility and static twopoint discrimination was 6 mm in two cases of lower lip replantation with 7 to 8 months of follow-up [4,59]. Another case could even purse his lips and regained sensation and the use of orbicularis oris and mentalis muscle [
Trauma and cancer ablation result in huge facial defects and microsurgical free flaps are the current trend of reconstruction. Since the first description of free groin flap transfer in 1973 [
Since its first description by Song et al. in 1984 [
The maximum dimensions of the flap that can be harvested are still debated. According to Koshima et al., the skin paddle could be up to 35 cm in length and 25 cm in width based on a single dominant perforator [
scending branch sends perforators through the septum (septocutaneous) between vastus lateralis and rectus femoris or through the vastus lateralis muscle (musculocutaneous) to supply the flap. The musculocutaneous perforators are the most common type and are responsible for blood supply in more than 86% of the cases and the septocutaneous perforators are responsible in about 12% of cases [88,101,102].
The line between the anterior superior iliac spine and the lateral border of the patella represents the axis of the flap and corresponds roughly with the intermuscular septum between the rectus femoris and vastus lateralis muscles. The main perforators for the anterolateral thigh flap are identified with the Doppler. They are usually located within an area of 5 cm around the midpoint of the axis of the flap [
The medial approach makes incision medial to the axis line, usually at the line between the inguinal femoral pulse to the uppermost point of patella. The dissection is done from medial to lateral and perforators are identified and looped. The shape hand size of the flap doesn’t need to be determined at this time. When all dissections are finished, the flap can then be designed according to the size, shape and three dimensional relationship of defect, especially when chimeric flaps are needed.
The lateral approach mandates the lateral margin of the flap to be determined first after Doppler study [
Dissection under loupe magnification (2.5× to 4.5×) is mandatory. Including more than one perforator initially provides a backup if one perforator is damaged during dissection. Dissection of the perforator(s) to the main pedicle is performed using the “deroofing” technique by cutting the muscles along the length of their fibers to liberate the perforators under stretching of the muscle fibers with instruments [104-106]. The numerous tiny branches that the perforators give to the muscle have to be ligated as far from the perforator as possible by using clips. If an unusually large branch were met while dissecting a perforator, it should not be ligated immediately because it may come from the next nearest perforator with a long intramuscular route. Patience is needed in perforator dissection [
Irrigating the perforator with 2% Xylocaine helps to prevent vasospasm and dryness. The perforator should not be stretched and pulsation transmitted throughout the length of the perforator should be observed to ensure that the perforator is perfusing the flap. Including more than one perforators and include a small muscle cuff or fascia at the point of entrance of the perforator to the flap help to define the original orientation of vessels and avoid twisting of the pedicle. Also, a fine suture that connects a branch stump of the main pedicle and the flap may prevent torsion and twisting of the pedicle. This suture should be removed after inset of the flap [
The concept that donor site can be closed directly when the width of the flap is less than 8 cm had been applied for a long time. If the flap width is more than 8 cm, the donor site should be closed with a skin graft to avoid compartment syndrome or skin necrosis [
The anterolateral thigh flap has many advantages over other free flaps including 1) long vascular pedicle; 2) large and pliable skin paddle with good color and texture matching [
The disadvantages of the anterolateral thigh flap include 1) anatomic variations; 2) hair growth in some male patient and influence on appearance and in intraoral reconstruction; 3) variable thickness of the flap. The Asian population has most reported series with average thickness 7 mm thick [100,113], which is about half of those in the Western population [
1) Explore the transverse branch of LCFA in the proximal lateral thigh to harvest a tensor fascia lata perforator flap.
2) Proceed dissection medial to the incision to elevate an anteromedial thigh (AMT) flap as a free-style free flap.
3) Elevate a free muscle flap based on the LCFA system with the coverage of skin graft.
4) Abandon the dissection and seek for another donor site. By following the proposed alternative choices, the reconstruction could be completed with a higher success rate.
Due to refinements in surgical technique and instrumenttation, the free flap survival rate at present is more than 95% in most centers. The microsurgeons are nowadays more interested in improving the aesthetic and functional results and reducing donor-site morbidity.
The concept of perforator flaps originated from the anatomic study of Taylor and Palmer [
Free-style perforator flaps harvested in a free-style manner, based only on the preoperative survey of Doppler signals, can be raised from any anatomic region [
The microsurgeons need to have superior microsurgical skills and be familiar with perforator flaps and intramuscular perforator dissection before attempting a free-style perforator flap; therefore, it is not an operation for the beginner. Moreover, surgeons need to be experienced in using the Doppler device. For example, in areas where large underlying vessels are present, the signal of the main vessel will obscure the signal of the smaller perforators [
Despite the advanced development of free ALT flaps and perforator flaps, there are still situations that can’t be solved by flaps alone. Rifle suicide gun-shot wounds [
Face transplantation has been shown thus far to be a viable option in some patients suffering severe facial deficits which are not amenable to current reconstructive techniques [
Before operation, patient selection is important. The Cleveland clinic used the parameters of Functional status, Aesthetic deficit, Comorbidities, Exposed tissue, Surgical history to develop a FACES score to objectively stratify face transplant candidates for their facial deficit during multiple steps throughout the screening process [
Gordon et al. reviewed all seven cases of facial transplant from 2005 to 2009 [
Ethic issues of facial transplantation are still being debated [
Facial transplantation reconstruct the function and the aesthetics at the same time, thus changed the traditional reconstruction ladder. However, to popularize facial transplantation still needs much more effort to organize institutions, a lot of medical and paramedical team works, organ procurement, surgical simulation and mock surgery techniques, which have been described above.
Application of microsurgery in facial trauma reconstruction started from replantation of amputated parts, progressed to free flaps, perforator flaps then finally facial allotransplantation in recent three decades. Surgeons in managing facial trauma should keep all these methods in mind to achieve better cosmetic and functional results. Replantation first, free flaps depending on the defect, and facial transplantation when extensive defect make the reconstruction ladder of managing complicated facial trauma using the microsurgery. Knowing the limits of these methods might stimulate more innovation and refinement. More and more facial transplantation are being performed worldwide. We expect to see it becoming as popular as free flap surgery.