Lateral approach to the deep branch of the superficial circumflex iliac artery for harvesting a SCIP flap

Clinical application of digital technology in the reconstruction of soft tissue defects of the lower extremity with free superficial circumflex iliac artery flap

Objective

This paper aims to investigate the feasibility and clinical effectiveness of digital technology in the clinical application of free superficial circumflex iliac artery flap (SCIP) for repairing soft-tissue defects in the lower extremities.

Methods

From January 2020 to December 2021, 16 patients with lower extremity soft tissue defects requiring flap repair were selected, and preoperative 3D digital reconstruction of the abdominal donor area and lower extremity recipient area were performed using digital technology combined with highly selective abdominal computed tomography angiography, and virtual design and flap cutting were performed using the software self-contained tool. During the actual surgery, the intraoperative design and excision of the superficial iliac circumflex artery were guided by the preoperative digital design, and the donor sites of the flap were closed directly.

Results

In all cases, digital models of the donor area of the abdominal SCIP were successfully established, which could clearly showed the distribution, course, and diameter of the main trunk and the perforators and other relevant anatomical information and successfully guided the design and excision of the flap during surgery. All flaps successfully survived after surgery, and both the flap recipient and donor sites healed in one stage. All patients were followed up for 2–12 months on average (mean 8.6 months), and the flaps were not bulky and had a satisfactory appearance, with no significant difference in color compared with the surrounding skin and a little pigmentation around the flap. Only linear scarring was left in the donor areas, and there was no restriction of hip movement.

Conclusion

This study used digital technology combined with a SCIP to repair lower extremity soft-tissue defects. The preoperative three-dimensional reconstruction of the digital model of the flap optimally designed the surgical plan, reduced the surgical risk and difficulty, shortened the surgical time, and had some significance for clinical precision, safety, and personalized design of the abdominal flap.

Do-It-Yourself Preoperative High-Resolution Ultrasound-Guided Flap Design of the Superficial Circumflex Iliac Artery Perforator Flap (SCIP)

The superficial circumflex iliac artery perforator (SCIP) flap is a well-documented, thin, free tissue flap with a minimal donor site morbidity, and has the potential to become the new method for resurfacing moderate-size skin defects. The aim of this study is to describe an easy, reliable, systematic, and standardized approach for preoperative SCIP flap design and perforator characterization, using color-coded duplex sonography (CCDS). A list of customized settings and a straightforward algorithm are presented, which are easily applied by an operator with minimal experience. Specific settings for SCIP flap perforator evaluation were investigated and tested on 12 patients. Deep and superficial superficial circumflex iliac artery (SCIA) branches, along with their corresponding perforators and cutaneous veins, were marked individually with a permanent marker and the anatomy was verified intraoperatively. From this, a simplified procedure for preoperative flap design of the SCIP flap was developed. Branches could be localized and evaluated in all patients. A preoperative structured procedure for ultrasonically guided flap design of the SCIP flap is described. A 100% correlation between the number and emergence points of the branches detected by preoperative CCDS mapping and the intraoperative anatomy was found.

The Superficial Circumflex Iliac Artery Perforator Flap in Lower Extremity Reconstruction

The superficial circumflex iliac artery perforator flap is evolved from the groin flap, which was one of the early free flaps with a good concealed donor site. By further understanding the anatomy of perforators and elevating the flap based on it, this will provide added advantage of being a thin flap, harvesting as a composite flap, and help estimate the limit of skin paddle dimension. Despite these advantages, the relatively short pedicle still remains a challenge where long pedicle flaps are needed. One should select the flaps based on the recipient defect condition along with surgeons' experience, knowledge, and preference.

Definition of perforator flap: what does a "perforator" perforate?

Perforator flap concept plays an important role in reconstructive surgery, because it allows less invasive and more complex reconstruction by preserving major vessels and muscles with intramuscular vessel dissection. Originally "perforator" represents vessel perforating the muscle, then vessel perforating the deep fascia regardless of muscle perforation. With technical progress in reconstructive microsurgery, the previous definition becomes inappropriate for least invasive flaps, only requiring intra-adiposal vessel dissection, such as superficial circumflex iliac artery perforator flap. Based on our experience of various least invasive flap reconstructive surgeries, a new concept for perforator flap has been developed. The new definition of perforator is a vessel perforating an envelope of a targeted tissue to be transferred; the superficial fascia for skin, the periosteum for bone, the perineurium for nerve, and the deep fascia for muscle. According to the new definition, all flaps can be precisely classified based on the corresponding "perforator".

Use of the transverse branch of the superficial circumflex iliac artery as a landmark facilitating identification and dissection of the deep branch of the superficial circumflex iliac artery for free flap pedicle: Anatomical study and clinical applications

BACKGROUND

The deep branch of the superficial circumflex iliac artery (SCIA) should be included when a large superficial circumflex iliac artery perforator (SCIP) flap is necessary, or when anatomical structures perfused by the deep branch are procured. The aim of this study was first to describe the anatomical features of the "transverse branch" of the deep branch of the SCIA in cadavers, and then to assess the efficacy of its use as a landmark for identification and dissection of the deep branch of the SCIA through clinical applications.

METHODS

Twenty groin regions from 10 cadavers were dissected. The course and the takeoff point of the transverse branch were documented. With the transverse branch used as a landmark for pedicle dissection, 27 patients (16 males and 11 females) with an average age of 51.7 years underwent reconstructions that used vascularized structures nourished by the deep branch of the SCIA. Aside from the skin paddle, an iliac bone flap was used in 10 cases, a lateral femoral cutaneous nerve flap in four cases, and a sartorius muscle flap in three cases. The defect locations included the head (seven cases), the foot (six cases), the hand (six cases), the arm (five cases), and the leg (three cases). The causes of reconstruction were tumors in 13 patients, trauma in six patients, infection in four patients, surgical procedures in three patients, and refractory ulcer in one patient.

RESULTS

In all specimens, the transverse branch was found underneath the deep fascia caudal to the anterior superior iliac spine (ASIS). The average distance from the ASIS to the transverse branch was 25.5 ± 13.0 mm (range, 5-50 mm). The average dimension of the flap was 13.1 × 5.9 cm² . All the flaps survived completely after the surgery; lymphorrhea was seen in one patient at the donor site. The average follow-up period was 12.9 months (range, from 2 to 42 months), and all patients had good functional recovery with satisfactory esthetic results.

CONCLUSIONS

The transverse branch was found in all specimens, branching from the deep branch of the SCIA. Successful results were achieved by using it as the landmark for identification and dissection of the deep branch of the SCIA. This method allows safe elevation of a large SCIP flap or a chimeric SCIP flap.