The hand has been regarded as one of the most crucial organs for daily activities; thus, hand injuries are very common in the clinic. With the development of industrialization and with the presence of frequent accidents such as traffic accidents, hand injuries are currently increasing daily in society. Such injuries often result in the loss and necrosis of skin and soft tissue to different extents and are often accompanied by tendon exposure, nerve injury and bone defects. Hand reconstruction is challenging due to the unique functions and appearance of the hand; above all, skin reconstruction in order to restore the function of the hand is always difficult in the clinic .
Due to the unique functions and appearance of the hand, to restore the glabrous skin of the radial digits is critical. An ideal tissue replacement should be antifriction, glabrous and with similar texture and plump subcutaneous tissue. It has been repoted that kinds of flaps have been successfully applied in clinic: digital artery island flap, free fibula side flap, thenar flap, for example. But, these flaps have some limitations, such as, skin grafting for donor area, postoperative scar, long operation time, last but not least, the flaps couldnot be designed too large, they are more suitable for single digit with smaller defect area.
Since abdominal flaps were first reported by McGregor and Jackson et al in 1972, they have gradually become ideal workhorse flaps for skin and soft tissue replacement in the hand. Abdominal flaps have many advantages, such as their consistent vessel anatomy, flexible design, harvesting simplicity, rapid postoperative recovery, and limited complications and wound infections . However, in addition to their advantages, these flaps also have limitations as well as disadvantages because if multiple finger injuries occur, the traditional surgical procedure used is often to artificially form syndactylia using an abdominal pedicled flap; this involves a secondary surgery for cutting the vascular pedicle and separating the fingers. Because of the long-term passive position, joint stiffness, discomfort position and unexpected flap avulsion often occur [14,15].
For decades, with the continuous development of microsurgery techniques and tools, supermicrosurgery, a technique involving the dissection and anastomosis of small vessels ranging from 0.3 to 0.8 mm in size, has revolutionized the field of vessel reconstruction, allowing the possibility of perforator flaps with thinner calibers . The concept of a perforator flap was first presented by Koshim and Soeda in 1989, and this flap roughly experienced three substantial processes of development: pedicle flap-free flap-perforator flap[15,16].
The perforator flap is a kind of flap that survives due to the blood supply from perforator vessels with small diameters (approximately 0.5 mm). Unlike other traditional flaps, the perforator flap does not depend on muscle or deep fascia and reduces the morbidity of the donor area to the minimum. Therefore, the use of this flap is an inevitable trend in the field of hand trauma and represents an opportunity for microsurgery to solve complex reconstructive problems. In recent years, various types of perforator flaps have been reported, such as the paraumbilical, anterolateral thigh, lateralthoracic, superficial circumflex iliac and gluteal artery perforator flaps.
In 2004, Koshima et al. first established the concept of the SCIP flap, constituting the dissection of a groin flap based on the superficial circumflex iliac artery (SCIA) . The SCIP flap is pliable, thin and reliable, and is one of the most demanding flaps with long vascular pedicles. This flap has many advantages by not only obtaining an aesthetic effect and functional outcome but also minimizing donor site morbidity with concealment of the scar, reducing the surgical time, and achieving one-stage surgical reconstruction.
The SCIP flap is one of the most advantageous flaps because it enables the reconstruction of multiple lesions with one source vessel. It can be designed with a lobulated appearance in order to repair two or more wounds simultaneously by anastomosing one group of blood vessels.
In recent years, with the development of perforator flaps, many studies have reported that these flaps can be successfully applied in many fields. The SCIP flap was widely used since it was first described in 2004 by Koshima et al, soon afterwards, Lita T and his colleague demonstrated success of the SCIP flap in reconstructive of head and neck defects . It has been reported in many department listed as follows: reconstructions of hand, breast, lower extremity, penis, limbs (Hong JP et al., 2013), urethral reconstruction (Yoo KW et al., 2012), oral maxillofacial reconstruction (Yue He et al., 2016) [18-20] and so on.
The SCIP flap plays an important role in clinical microsurgery due to its remarkable aesthetic and functional merits. However, it also has some limitations, perforator flap surgery is relatively complicated mainly because of the short arterial pedicle, arterial anatomical variability and tiny caliber of the vessels. Due to these difficulties, the performer should be experienced instead of microsurgically novice.
Meanwhile, preoperative imageological examination and anatomical assessment of vascular mapping were important for the successful flap transfer. Diversified anatomical variations of dominant vasculature in the groin area especially SCIA have been reported in previous study [21,22]. So preoperative CDS mapping and CTA combined with three-dimensional volume-rendered reconstruction were performed to identify the location, the whole vessel stream, vascular trunk and side branch of SCIA. Following the tiny branches, the main trunk of the SCIA was detected, and then the projection lines was marked on body surface with gentian violet pen.
The SCIP flap is crucial for hand reconstruction not only in adult patients but also in pediatric patients. Previous relevant studies have mainly focused on adults, and few studies have reported the use of perforator flaps in pediatric patients. To be certain, vascular anastomosis in pediatric patients certainly poses a unique clinical challenge.
Children's fingers are smaller than adults’ fingers, while the vascular caliber of the traditional flap is wider, which makes the anastomotic process more laborious. The SCIP flap, with its small caliber, flexibility, minimal donor site morbidity, and scar concealment, is highly suitable for pediatric patients. This flap can be designed with alobulated appearance to repair two or more wounds in order to avoid the inconsistencies in caliber and the risk of a second-stage operation. To our knowledge, the relevant study of pediatric patients is not common, this study is the first to conduct a free single-pedicle bilobed SCIP flap for multi-digit defect reconstruction in pediatric patients.
Seven pediatric patients who underwent the reconstruction of finger defect with free single-pedicle bilobed SCIP perforator flaps were collected, all flaps survived and with no complications except one child with scar contracture of interphalangeal joint, finger function recovered well after release surgery and postoperative systematic rehabilitation training, the flaps achieved good interphalangeal ranges of motions as well as tactile sense, pain sense and two-point discrimination recovery. The donor area is sutured primarily and with well-concealed scar.
In spite of these advantages, Our study is limited with the small sample size and lack of objective monitoring index. Also the longstanding operation and difficulties in harvesting flap are apparent limitations. Further studies with larger sample should be conducted to consolidate this research and develop more practical variations.