Introduction

High-energy trauma often leads to complicated wounds with three-dimensional deficits in the extremities involving superficial soft tissue defects and dead spaces of varying location, which are challenging to precisely and efficiently repair simultaneously [1,2,3]. The challenge of this type of reconstruction requires not only coverage of surface soft-tissue defects but also appropriate obliteration of dead space in a single procedure.

Numerous reconstructive strategies have been described for repairing complex three-dimensional soft tissue in the literature [4, 5]. Free latissimus dorsi muscle flaps have been widely accepted as a reliable option for reconstruct complicated defects with three-dimensionally inset multi-component tissue transfer. Nonetheless, reconstruction of this wound with a musculocutaneous flap always is more challenging for the reconstructive surgeon because of its restriction in the range of motion of muscle components. Moreover, those approaches are hindered by higher donor-site morbidity and poor contouring [6,7,8,9].

Recently, several studies have demonstrated that chimeric perforator flaps are one of the most valuable strategy for reconstructing complicated wounds with three-dimensional deficits, which can be attributed to their greater spatial freedom, more flexible design, the economy of donor incision, and superior aesthetic outcomes.[1, 10,11,12,13]. The latissimus dorsi (LD) muscle-chimeric thoracodorsal artery perforator (TDAP) flap has been introduced as a reliable strategy for repairing complicated wound [14]. However, harvesting chimeric perforator flaps with conventional design often lack the versatility to offer adequate tissue volume and allow precise tissue positioning to optimally cover the wound. Notably, when reconstructing complicated wounds with three-dimensional tissue deficits, customized chimeric perforator flap designs are necessitated for precisely coverage of superficial soft tissue defects and effective obliteration of dead space to facilitate wound healing. Moreover, the traditional designing of a LD muscle-chimeric TDAP flap typically requires time-consuming intramuscular dissection, leading to longer operative time and higher donor-site morbidity. To address this, three different types of LD muscle-chimeric TDAP flaps were designed to minimize donor-site morbidity and shorten the operative time. Thus, our report focused on the various designs for customized reconstruction of complex three-dimensional defects to minimize donor-site morbidity and shorten the operation time, which has rarely been addressed in previous studies. To the best of our knowledge, the use of individually designed chimeric perforator flaps to reconstruct complex three-dimensional soft tissue defects has not been studied in the context of free TDAP flaps.

The purpose of this study was to present our experience on a novel design of the TDAP chimeric flap and its various designs for the customized reconstruction of complex three-dimensional defects in the extremities.

Patients and methods

Between January 2012 and June 2020, seventeen patients who suffered with complicated wound with three-dimensional tissue deficits were performed extremity reconstruction using a LD-muscle chimeric TDAP flap. Patient ages ranged from 2 to 39 years (mean age 20.24 years; 7 females, 10 males). Of these patients, five patients suffered from chronic osteomyelitis, two were injured by a crushing incident, three underwent tumor resection surgeries, and the remaining seven patients were injured in road traffic accidents. The complex soft-tissue defects were classified into three types according to the location of dead space. When the dead space was located at the center of the wound, it was classified as type I; when the dead space was located at the edge of the wound, it was classified as type II, while Type III was classified as a wound with extensive surface soft-tissue defect and dead space. Additionally, the type III category was further classified into two subtypes based on the location of dead space. When the dead space was located at the center of the wound, it was classified as type IIIA; when the dead space was at the edge of the wound, it was classified as type IIIB. Patient details are presented in Table 1. The study conformed to the ethical guidelines of the Hospital Ethical Committee of the ** scar-related issues at the donor site [35]. Our previous study also demonstrated that the transverse design of the scapular artery perforator flap presented a more aesthetic appearance. Moreover, the transverse design causes less lateral movement of breast mounds and nipples during donor-site closure. Considering the donor site's cosmetic appearance improvement, the recent practice showed that using a transverse designed flap was more effective than using a non-transverse one. Also, for female patients, the scar can be readily concealed with a brassiere.

The limitations of this study include the small number of cases as well as its retrospective character. And other limitations include the absence of a direct comparison group and a standardized assessment tool for the objective assessment of the result following reconstructive surgery. Thus, further studies, such as prospective case–control or randomized studies, are needed in future study.

Conclusions

To summarize, the TDA chimeric perforator flap is a reliable option for the reconstruction of complex three-dimensional defects of the extremities. This flexible approach provides various designs for customized coverage of complex three-dimensional defects with limited donor site morbidity. Moreover, the flexible shape of this flap permits alteration to match the shape of the recipient site. In addition, we introduced a novel classification system of chimeric perforator flaps for reconstructive surgeons and trainees to gain a better understanding of chimeric flaps design and allow safe, effective, and aesthetically superior reconstruction of complex three-dimensional defects.