Abstract

Surgical reconstructive techniques continue to evolve as dermatosurgeons combine clinical expertise, technical skill, and innovation. In some cases, such innovation can result in better outcomes in terms of tension management, vascular supply preservation, and esthetic appearance.

The double-opposing rotation advancement flap, also known as the Ying-Yang flap due to its yin-yang mode of action, is often applied in the scalp region, where it provides excellent results with minimal complications. However, data supporting its application in less conventional anatomical sites remains limited.

We present two independent cases involving primary defects resulting from skin tumor excisions, successfully reconstructed with the Ying-Yang flap in atypical locations: the medial foot ankle and preauricular regions. Tension-free closure was achieved in both cases, and follow-up at two months demonstrated great wound healing.

While surgical excision remains the gold standard for treating skin cancer, these cases highlight the double-opposing rotation advancement flap as a versatile and effective reconstructive option beyond its standard indications.

atypical site, double-opposing rotation flap, foot ankle, reconstructive surgery, skin cancer, preauricular region, Ying-Yang flap

A tissue movement procedure, known as a flap, is a surgical technique used in reconstructive surgery when simpler primary closure methods are insufficient.^[1] Using a flap allows for 1) redistribution of tension vectors, generated by the defect, 2) improved aesthetic outcomes through better matching of skin color, texture, and thickness at the recipient site, while also 3) preserving similar blood supply and utilizing the tissue laxity of the surrounding area.^[2]

Different classifications exist; however, the most clinically practical may be the one based on the flap’s primary movement - categorizing flaps by basic tissue motion into transposition, advancement, rotation, and interpolation types.^[1]

Rotation flaps are often preferred when primary wound defect closure is not feasible or desirable due to esthetic considerations or the risk of tissue distortion.^[2] They are particularly useful when tension needs to be redirected around a free margin.^[2]

Each flap has specific indications based on its anatomical location^[2], but flaps that are not traditionally used for certain areas can, in some cases, be successfully applied to less conventional sites.^[3]

We present two independently and successfully treated patients, both utilizing the Ying-Yang flap technique for defect closure in atypical sites—the right medial foot ankle and the left preauricular regions. These cases highlight the adaptability and effectiveness of the Ying-Yang flap across varied anatomical regions. Importantly, they underscore the necessity for a personalized, patient-specific approach in reconstructive surgery. To achieve the best functional and aesthetic results, dermatosurgeons must frequently rely on both technical expertise and thoughtful innovation.

The management of skin cancer is increasingly recognized as a multistep process, beginning with complete tumor resection, often followed by the selection of an appropriate reconstructive technique.^[4] This decision is largely determined by the size and location of the tumor, with the goal of preserving tissue function while achieving an esthetically pleasing outcome, especially in cosmetically and functionally sensitive areas.^[4]

Flaps can be versatile in nature, meaning that a flap not typically used for a certain anatomical location can still be effectively applied to less common sites, often providing the same results.^[5] Apart from the size and location of the tumor, other factors often determine the choice of reconstructive technique, such as the presence of exposed structures, patient-specific characteristics, and comorbidities.‌^[5] A case of a patient with giant basal cell carcinoma on the back was presented by colleagues, where the resulting primary defect was extensive and managed using a reconstructive technique not typically employed in that region.^[5] This demonstrates that well-established surgical methods can sometimes be successfully adapted to unconventional locations.^[5] Moreover, opting for less invasive procedures may reduce postoperative complications and shorten recovery time.^[5]

A classic approach of tissue rearrangement is the rotation flap, which involves mobilizing adjacent tissue to redirect tension vectors and recruit tissue from areas of laxity—particularly useful for closing defects not suitable for primary closure.^[6]

Tension-related issues require a more precise flap design that can adequately redistribute tension across multiple vectors, thereby minimizing potential wound complications and optimizing healing outcomes.^[7] An interesting variant addressing such concerns is the double opposing rotation-advancement flap—the Ying-Yang flap—which can provide tension-free closure and adequate defect coverage.^[7]

The bilateral rotation advancement (Ying-Yang) flap is a commonly used technique for managing scalp defects requiring proper tissue coverage.^[8] This flap is carefully designed and sufficiently large to close the primary defect while preserving the surrounding skin without distortion. ^[8] The initial step involves outlining two opposing rotational flaps, in a Yin-Yang manner, each approximately twice the length of the primary wound diameter.^[9] The curvilinear incision begins at the supero- or inferolateral margin of the defect, with the rotational arc optimized by designing the flap at a slightly greater height.^[10] The procedure continues with flap elevation, careful dissection, and undermining down to the hypodermis to preserve vascular supply.^[9] The pedicles consist of subcutaneous tissue, ensuring adequate perfusion.^[9] Tension-free adaptation is achieved, with the tension vectors more evenly distributed along the suture line.^[8-10] Finally, the secondary wound defect is closed using different suture techniques.^[8,9]

Rotation flaps are highly versatile in nature, providing excellent defect coverage and effective redistribution of tension vectors, while also being relatively time-efficient procedures, typically completed in under an hour.^[10] Skin grafts or free tissue transfer cannot be employed in the same manner as rotational flaps, as they often fail to match the surrounding skin’s color, texture, and thickness as effectively.^[10] This can lead to suboptimal esthetic outcomes and potential patient dissatisfaction with the final result. ^[10] The majority of the patients (74.7%) can be discharged either immediately or a within a few hours postoperatively. ^[10] Reported postoperative complication rates are low (9.4%), with approximately 3.6% of cases requiring additional surgical interventions due to wound healing issues and/or necrosis.^[10]

The Ying-Yang reconstructive technique is primarily reserved for scalp reconstruction.^[9,10] However, when properly performed, it can serve as a highly effective option for tension-related defect closures in less conventional anatomical sites.^[11] For example, a patient underwent surgery for an open, chronic wound on the right elbow.^[11] Following surgical exploration and debridement of devitalized tissue, a tension-free closure was successfully achieved using two opposing rotational (Ying-Yang) fasciocutaneous flaps.^[11] Tension was tested by elbow flexion, which revealed no tension on the incision site.^[11] A complete closure and healing of the wound was achieved^[11], making this technique an excellent choice for reconstruction in such areas. These cases often involve prolonged healing, with full cosmetic recovery taking up to a year.^[11] In comparison, our first case presented a similar challenge. The patient initially expressed concern due to the extended healing process, with persistent erythema and swelling noted at the site. She was monitored monthly, and by the second-month follow-up—after complete suture removal—the defect had begun to integrate well with the surrounding skin.

A V-Y advancement flap can also be applied to defects of the posterior heel and ankle region, with generally favorable outcomes and minimal complications reported.^[12] However, superficial tip necrosis of the flap should be considered when selecting the appropriate technique.^[12] Another option for use in less conventional sites is the bilobed flap, a versatile local transposition flap that distributes tension over a wider surface area compared to a conventional rotational flap.^[13] Nevertheless, due to its crescentic design, there is a risk of developing a pincushion deformity from subdermal tissue contraction.^[13]

Case reports or articles describing the use of the Ying-Yang flap in the preauricular zone are scarce. Belmahi et al.^[14] reported a case involving a preauricular cutaneous defect managed following a Mustardé cheek rotation flap. In this article, nine patients underwent excision of basal cell carcinomas.^[14] While the Mustardé flap was designed, the skin’s undermining was limited to the lower border of the mandible, effectively creating a geometrical base for the design of an opposing temporoparietal rotation flap.^[14] Although the Mustardé flap is an excellent reconstructive option, its limited undermining in certain areas may necessitate the use of a secondary flap.^[14] In our second patient, a double opposing Ying-Yang flap was successfully utilized in the left preauricular area. Although this is not a typical site for application of this flap, it provided similar vascular supply, effective defect coverage, and efficient redistribution of tension vectors—once again highlighting the versatile nature of the flap.

Other reconstructive options can be effectively applied when managing soft-tissue defects.^[15] Tissue expansion is considered a suitable alternative for managing large defects where local tissue is insufficient for flap formation. ^[15] When combined with other reconstructive techniques, this approach can provide adequate coverage while minimizing scar formation and donor-site morbidity.^[15] Another effective technique, either alone or in combination with other methods, is the Z-plasty, which is particularly valuable for correcting scar deformities, such as those following burns.^[16]

The formation of pathological scars following surgical interventions, injuries or burns remains a challenge for every reconstructive surgeon.^[17] Reducing the scar size and its pigmentation, pain or pruritus can be difficult.^[17] In such cases, hypertrophic scars and keloids may be effectively managed with high-intensity focused ultrasound thermotherapy.^[17]

The small sample size of two cases clearly does not constitute a large-scale study, and the short follow-up period of two months is insufficient to assess long-term outcomes. However, despite these limitations, both patients reported highly satisfactory results. Moreover, postoperative complications were minimal or absent.

The concept of an “optimal flap” remains a topic of ongoing debate, as not every flap is universally suitable for all anatomical location - each case requires individualized consideration based on defect characteristics and patient factors.^[7]

Larger-scale studies are needed to evaluate specific techniques more fully. However, even small case reports can provide valuable insights that aid in selecting the most appropriate reconstructive approach.

While not a novel approach in the reconstruction of skin cancer defects, this technique remains a safe, reliable, efficient, and time-saving option—particularly in managing scalp defects^[9,10], though its application may extend to other anatomical sites. We present two independent case reports demonstrating that a classical flap design can be successfully employed in less conventional anatomical sites, despite not being commonly used outside standard locations. Every dermatosurgeon should aim to approach each case with clinical expertise, following established indications and contraindications, yet remain open to modifying and adapting techniques when appropriate. With careful planning and anatomical consideration, innovation within safe boundaries can lead to excellent reconstructive outcomes.

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The authors have declared that no competing interests exist.

• The authors declared that no clinical trials were used in the present study.
• The authors declared that no experiments on humans or human tissues were performed for the present study.
• Written informed consent was obtained from the patients for the publication of this case report and any accompanying images.
• The authors declared that no experiments on animals were performed for the present study.
• The authors declared that no commercially available immortalised human and animal cell lines were used in the present study.

The authors declare that no AI was used to generate the article text or clinical images.

No funding was received.

All authors contributed equally to the creation of the manuscript.

The data that support the findings of this study are available from the corresponding author upon reasonable request.

Not applicable.