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 [11]. After that, revascularization of incompletely severed digits was proven feasible by Kleinert and Kasdan in 1965 [12]. The first successful digital replantation was performed by Komatsu and Tamai in 1968 [13]. The facial replantation started from 1974, when the first successful replantation of the scalp was done by Miller et al. [14]. Later, James was the first to microsurgically replant the upper lip and nose in a 3-year-old girl bitten by a dog [8]. Finally, in 1980, Pennington et al. used vein grafts and the superficial temporal vessels to replant an ear [15].

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 [7]. Various alternatives have been mentioned to relieve venous congestion, such as milking, pin pricking, using medicinal leeches [19-21], an artery-to-vein shunting/ fistula [22-24]. Chemical leeches [4,25] were proposed due to unavailability of medicinal leeches, risk of systemic infection, and difficulties with patients’ acceptance. This allows venous blood to escape into the dressing while an adequate venous microcirculation is being reestablished [26]. Blood loss could be great and blood transfusion might be needed to maintain adequate hemoglobin level. Post-operative care is very important. Venous congestion usually mandates early intervention including drainage, reopening of the drainage channels with a needle, flushing soaking with heparin sodium solution until the collateral circulation establishes. Others include controlling infection, increasing blood volume, dilating vessels and special nursing [27]. The benefit of drugs such as prostaglandin E1 or hyperbaric oxygen therapy is not clear [28].

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 [7].

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 [38]. The entire scalp can survive based on a single artery and a single vein if there is adequate flow [39-42], but two sets of arteries seems to be safer than single set [17,43]. Vein grafts are usually needed. If arterioarterial repair is not possible, arteriovenous anastomosis can be done [44]. Anastomosing a few veins before arterial anastomosis helps to reduce the blood loss from the edges of the avulsed segment [45].

A good venous return would be more important for a successful replantation than the number of vessels anastomosed [37]. To improve venous return, surgeons may use many veins [46,47], leeches [48], or incise the skin to allow venous bleeding [5]. Using a second artery in the scalp for anastomosis to a recipient vein to allow egress of blood was also reported [49]. Hematoma formation under the replanted scalp is one of the commonly reported complications which lead to compromise of the tissue [17,50].

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 [29]. Secondary revision by tissue expansion of the surviving portion of the scalp replant may be the best method of correcting any residual alopecia [30,37,51,52]. All reports showed good return of hair growth in the surviving segments of scalp. Even though the scalp was turned 180 degree for any reasons, the hair growth is also good [53,54].

Nerve repair is not easy in scalp replantation due to avulsion [55]. Only 35% can be repaired in a 20-cases study [16]. The sensory return ranges from protective sensation without nerve repair [34] to 15 mm at two-year follow-up with nerve anastomosis [49]. However, Ueda reported sensory recovery with no nerve anastomosis eight months after surgery mainly from the area along the supraorbital nerve. Temporary sensory disorientation also presented. The cutaneous threshold in the SemmesWeinstein test finally recovered to almost the normal range, possibly due to spontaneous nerve anastomosis by chemotaxis [55].

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 [82] and free gracilis flap transfer in 1976 [83], microsurgical free flaps have been in clinical use for more than three decades and is a routine practice in many hospitals nowadays. The other well-known flap is free latissimus dorsi muscle flap, which can provide large mass of well vascularized tissue [84] to tamponade dead space. Rectus abdominis muscle flap is also popular for defect coverage (Figures 1, 2). Because the muscle flaps are bulky and donor-site morbidity is common, development of muscle-sparing flaps like the fasciocutaneous flaps solved the problem. Here we emphasize the anterolateral thigh flap.

Since its first description by Song et al. in 1984 [85], the anterolateral thigh flap has been gaining popularity among microsurgeons. It is versatile and reliable in head and neck surgery because reconstruction of some of the soft tissue defects requires thin, pliable tissue and may encounter different defects at the same time [86-90] (Figure 3). The anterolateral thigh flap can be thinned using simple and effective procedures [89,91,92]. The distal stump of the pedicle can be used to anastomose vascularized bone or another soft tissue flap, thus creating “mosaic” flaps [93]. Mostly used in facial reconstruction is combining the vascularized fibula bone flap for mandibular reconstruction [94]. When more complex reconstruction is needed, the “chimeric” flaps in a freestyle fashion based on the lateral femoral circumflex axis to include skin flaps, vastus lateralis muscle flap and tensor fasciae latae flap in combination can reconstruct different defects in the same region at the same time [92, 95-99]. Finally, if more than one perforator is available, the skin flap can be separated into smaller skin flaps, each one of them based on one perforator.

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 [100]. The axial vessel supplying the anterolateral thigh (ALT) flap is the lateral circumflex femoral artery (LCFA). Its de-

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 concept of perforator flaps originated from the anatomic study of Taylor and Palmer [120]. The study described mean of 276 cutaneous perforators of 0.5 mm diameter or greater in the whole body. They connect to each other by a system of ‘“choke vessels” to form a continuous network in supra-fascia tissue level to the skin [120]. Later on, Taylor et al. demonstrated using a Doppler device to plan a skin flap around any of these perforators [121]. Wei et al. clarified the definition of perforators as those cutaneous vessels that penetrate the muscle and then pierce the fascia to reach the skin [122]. Since then, flap surgery has entered a new era, and numerous perforator flaps have been described [123, 124].

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 [125] and transposed locally to cover defects in adjacent anatomic regions with single-Free-Style Local Perforator Flap (FSLPF), multi-FSLPF and peninsular-FSLPF [126], or free-style free perforator flaps [127]. Free-style local perforator flaps may provide better aesthetic results than non-perforator based flaps for the coverage of a defect because the skin around the flaps has similar texture, thickness, color and least donor-site morbidity [125], especially in facial reconstruction. The length of the pedicle and the size of the vessel diameter could be large enough to obviate the supramicrosurgery techniques [125, 128]. Backup vessels and backup flaps are prepared if possible when there is no suitable vessel or damage of the pedicle [128].

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 [129]. Other limitations of the technique are 1) possible unpredictable course of perforators [128]; 2) possible small and short perforators that are difficult to harvest or inset; and 3) more conservative intraoperative flap thinning compared with that of conventional flaps; 4) not appropriate for complex defects which require chimeric flaps [128]; 5) inaccurate and insufficient Doppler investigation in lower back-gluteal region and immature infant vascular system [126].

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 [130], neurofibromotosis [131], animal bites, cancer ablation and burn injury may result in extensive facial deformity (loss of at least 25% of facial surface or important facial units such as nose and lips) [132] and complex naso-orbital-maxillary defect. Free tissue transfer and numerous autologous flaps can obliterate dead space but cannot match the delicate details of a completely amputated nose and a functional upper lip. Ultimately, the outcome of simulating mimetic musculature influencing “one’s unique appearance” is disappointing [130,133].

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 [134]. In order to achieve the “replacing like with like” principle, many centers in France, China, United States, and Spain had performed facial transplanttation to solve the problem [130,135-140]. From November 2005 to April 2010, 11 facial transplants had been performed worldwide [141]. In the first three cases, only soft tissue was transferred. The fourth case (also the first case in United States) included maxilla and palate for near-total facial transplantation [142]. The promising subspecialty of composite tissue allotransplantation, particularly maxillofacial allotransplantation, may soon become a clinical standard [133,143].

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 [134]. The surgical aspect of facial transplantation involves complex vascular anatomic study, mock surgery and surgical techniques [140,142]. The post-operative immunosuppression with antithymocyte globulin, tacrolimus, and mycophenolate mofetil [130], methylprednisolone [139] parallels the kidney transplantation [144]. Cytomegalovirus and pneumocystis prophylaxis [139] are necessary when indicated. Acute rejection is common and oral mucosa has earlier predictor of acute rejection episodes than the skin because of being more antigenic [144]. Biopsy of mucosa is easy and scarless. The risks of mandatory lifelong immunosuppression should be deliberated by each institution’s multidisciplinary face transplant team [134].

Gordon et al. reviewed all seven cases of facial transplant from 2005 to 2009 [134]. Overall long-term function of facial alloflaps has been reported to be satisfactory. Sensory recovery ranges between 3 and 6 months, and acceptable motor recovery ranges between 9 and 12 months. A cost analysis done by the Cleveland clinic for the first Unites States face transplant showed similar considerable cost to multiple conventional reconstructions. However, it is priceless to alleviate psychological and physiological suffering, better functional recovery and fulfill the long-lasting hope for social reintegration [145].

Ethic issues of facial transplantation are still being debated [146] but recent reports showed good psycho-societal outcome, quality of life and subject benefits against subject risks [147]. The benefits had been maximized and harms minimized through subject selection, team expertise, and preparation [134,148].

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.