Clinical Application of Free-style Perforator-based Stepladder V-Y Advancement Flap for Repair of Small- to Medium-sized Wound Defects of the Posterior Trunk

Abstract

Background:

Back wounds can be caused by trauma, infection, or tumor resection and are potentially associated with exposure of muscles and dead space. Due to the thick and inelastic nature of the skin on the back, these wounds usually cannot be closed directly, and skin grafts or flap reconstruction are often necessary. This study aimed to investigate the clinical application of a free-style perforator-based stepladder V-Y advancement flap in the repair of small- to medium-sized wound defects in the posterior trunk.

Methods:

Anatomical studies were performed on lateral thoracodorsal cadaver specimens to characterize the location, diameter, and alignment of the perforators of the circumflex scapular artery, dorsal scapular artery, and posterior intercostal artery. Then, from January 2016 to December 2021, these perforating branches were clinically applied to design and perform free-style perforator-based stepladder V-Y advancement flaps for the reconstruction of small- to medium-sized back wounds.

Results:

Twelve patients with skin and soft tissue defects of the back underwent free-style perforator-based stepladder V-Y advancement flaps. The defect area ranged from 5.5 × 5.0 cm to 9.5 × 8.5 cm, and the flap area ranged from 11.0 × 6.0 cm to 21.0 × 10.0 cm. All donor sites were closed with multilayered suturing. The survival rate of the flaps was 100%. One patient developed flap tip necrosis, which was successfully treated with daily dressing changes. All flaps achieved adequate and durable reconstruction with excellent contouring during follow-up, ranging from 8 to 12 months.

Conclusions:

The free-style perforator-based stepladder V-Y advancement flap is a safe and reliable method for repairing small- to medium-sized defects of the posterior trunk. This local flap is a well-vascularized, sensate, and pliable option, and the appearance of the flap is morphologically and functionally sound.

Takeaways

Question: What is the clinical application of a free-style perforator-based stepladder V-Y advancement flap for the repair of small- to medium-sized wound defects in the posterior trunk?

Findings: The free-style perforator-based stepladder V-Y advancement flap is a safe and reliable method for repairing small- to medium-sized defects of the posterior trunk.

Meaning: The free-style perforator-based stepladder V-Y advancement flap is a well-vascularized, sensate, and pliable option, and the appearance of the flap is morphologically and functionally sound.

INTRODUCTION

Wounds of the posterior trunk are most commonly caused by trauma, infection, or tumor resection and are often accompanied by exposure of underlying structures including muscle or bone. The thickness and poor elasticity of the skin of the back frequently result in wounds that cannot be closed primarily. Therefore, repair of dorsal soft tissue defects routinely requires flap reconstruction.^1,2

The pedicled latissimus dorsi muscular flap and trapezius myocutaneous flap are the gold standards for reconstruction of the posterior trunk. Unfortunately, these techniques are complicated and are accompanied by morbid donor sites.^3,4 Conventional latissimus dorsi myocutaneous flaps, propeller perforator flaps, and keystone flaps are often too bulky for smaller defects and result in a skin island in the upper middle back. Further, these traditional flaps are unable to repair more distant wounds due to the limited length of the vascular pedicle.⁵

The drawbacks associated with current approaches encourage the exploration of new techniques for treating posterior trunk defects. We propose a variation of a previously described flap that uses the perforating vessels of the circumflex scapular artery (CSA), the dorsal scapular artery, and the posterior intercostal artery.^4,6 Hayashi and Maruyama⁷ first applied the stepladder V-Y advancement flap for the repair of postero-plantar heel ulcers. To avoid the postoperative incisional scar and secondary scar contracture associated with the usual V-Y approach of this flap, and based on the principle of flap design by Hayashi and Maruyama, we applied the stepladder V-Y advancement flap to small- to medium-sized back wound defects.

To evaluate the feasibility of this flap, we undertook a 2-part study. First, the anatomical specifications of the perforators of the CSA, dorsal scapular artery, and posterior intercostal artery were established in a cadaveric model. Next, the free-style perforator-based stepladder V-Y advancement flap was clinically applied to patients with small- to medium-sized back wound defects.

METHODS

Anatomical Study

Cadaver sections were acquired from the Department of Anatomy, Guangdong Medical University. Before dissection, red latex was perfused via the axillary artery. After red latex perfusion, the skin was raised, and the subcutaneous tissue was dissected under a microscope. Next, once piercing points of the perforators to the deep fascia were identified, the perforator vessels were tracked and protected, and the extra skin and soft tissue were removed. A plastic and reconstructive surgeon (Z.W.) with 10 years of experience performed microsurgical dissection of the perforator vessels. The CSA, dorsal scapular artery, and posterior intercostal artery were located and isolated. The length, diameter, and location of each artery were recorded, in addition to the number and location of perforator vessels. The vessel diameter and length of the perforators were also collected. Measurements were collected using vernier calipers (accurate to 0.1 mm) and stainless-steel rulers (accurate to 1 mm).

Clinical Study

This study was conducted in accordance with the Declaration of Helsinki, and informed consent was obtained from all patients before treatment. Patients with posterior trunk defects treated by a senior author (W.Z.) were considered for inclusion in this study. Exclusion criteria included patients with diagnoses of diabetes mellitus, peripheral vascular disease, local infection, and cicatrix.

In addition to dimensions of the defect area, intraoperative variables recorded included the number, length, and direction of arterial perforations. Postoperatively, donor site morbidity, minor complications, major complications, and sensory outcomes were reported. Postoperative complications include dehiscence, necrosis, hematoma, bleeding, congestion, scar contracture, and infection.^8,9 Major complications are defined as complications requiring reoperation, whereas minor complications could be treated conservatively.¹⁰ Sensory outcome was evaluated using the sensory function evaluation criteria proposed by the British Medical Research Council (Table 1).

Table 1.

Medical Research Council Scale

S0	No sensation
S1	Deep cutaneous pain in the autonomous zone
S2	Some superficial pain and touch
S2+	Superficial pain and touch plus hyperesthesia
S3	Superficial pain and touch without hyperesthesia; static 2-point discrimination >15 mm
S3+	Same as S3 with good stimulus localization and static 2-point discrimination of 7–15 mm
S4	Same as S3 and static 2-point discrimination of 2–6 mm

S3, S3+, and S4 indicate functional sensory recovery.

Surgical Techniques

After evaluation of the posterior trunk defect, preoperative Doppler ultrasound was used to detect the location and direction of the peripheral arterial perforation of the wound. The artery with the clearest point of penetration of the deep fascia was selected and marked as the flap’s feeding artery.

After satisfactory anesthesia, patients were prepared in either the prone or lateral position. Then, the incision line was marked 1–2 cm away from the edge of the defect. Flap design was based on the anatomy of the perforators and preoperative Doppler ultrasound results, with the larger perforators being selected as the tips of the flaps. The longitudinal length of the flap was designed to be 2.5–3 times the longitudinal length of the defect, divided into 3–4 steps. The 2 arms of the steps formed multiple “V”s. The first level of the stepladder flap was designed to be slightly wider and longer than the defect. The angle of the first V-shaped step was the largest, at 60–120 degrees. Each subsequent step has a reduced angle and area (Fig. 1). The flap design was checked to ensure the possibility of tension-free closure of the donor site by pinching the skin in the orientation of the donor site wound closure.

Fig. 1.

Illustration of the preoperative design.

Next, the incision was made along 1 side of the flap marking deep to the superficial surface of the deep fascia. Lifting the skin toward the tip and carefully dissecting around the 1–2 perforator vessels marked preoperatively by Doppler ultrasound, the incision was furthered to the other side of the flap, and microscopic dissection continued until the entire flap was raised. The flap was advanced to the defect, and the inset was adjusted accordingly to achieve tension-free closure. Finally, the 2 arms of each small V-shaped step were closed with simple interrupted sutures. Two surgical silicone drains were placed below the flap for drainage. Routine postoperative dressing changes were performed once per day, and the patients were instructed to avoid placing pressure on the flap. After 3–5 days, silicone drains were removed in stages, one at a time, after the drains had less than 10 mL of fluid within 24 hours. Stitches were removed intermittently, starting on postoperative day 12, with all stitches removed by postoperative day 14.

RESULTS

Anatomical Study

Five fresh frozen cadavers with 10 total dorsal sections were prepared and dissected. Figure 2 depicts a completely dissected dorsal section. In all 10 specimens, the CSA originated from the subscapular artery approximately 3.0 cm below the axillary artery and was accompanied by 2 veins. The main trunk length of the CSA was 48.7 ± 18.5 mm with a diameter of 3.1 ± 0.5 mm. The dermal branch of the CSA was noted to consistently penetrate from the deep fascia and divide into 3 branches: the ascending branch, transverse branch, and descending branch. The diameter of the ascending branch was 0.8 ± 0.1 mm. It traveled in a spiral pattern inward and upward obliquely, reaching or exceeding the scapular spine and anastomosing with branches of the suprascapular artery, the transverse cervical artery, and thoracoacromial artery to form a rich vascular network. The diameter of the transverse branch was 1.1 ± 0.1 mm. It was accompanied by a large number of perforating vessels. The shape of these perforators was either arterial arched or stepped, and they anastomosed with other vessels in the midline region in a reticulated or arched pattern. Importantly, the perforators also anastomosed with the perforating branches of the dorsal scapular artery. The diameter of the descending branch was 0.9 ± 0.1 mm. This branch traveled obliquely inward and downward, with 3 main perforating branches. Each perforator anastomosed with the other branches and the perforating branch of the thoracodorsal artery at the subscapular angle.

Fig. 2.

Identification of arteries: A–C, dorsal scapular artery; D, medial branch of posterior intercostal artery; E and F, lateral branch of posterior intercostal artery; G–I, CSA; J–L, thoracic dorsal artery.

The dorsal scapular artery was noted to originate from the transverse cervical or subclavian arteries, 5.6 ± 0.9 cm from the median line. It accompanied the dorsal scapular vein and the dorsal scapular nerve and passed underneath the levator scapulae muscle to reach the superior angle of the scapula. It then descended below the rhomboid muscle along the vertebral margin of the scapula to reach the inferior angle. It had a diameter of 1.4 ± 0.5 mm and a length of 12.4 ± 1.8 cm. It anastomosed with the suprascapular artery and the CSA.

The posterior intercostal artery originated from the thoracic aorta and traveled along the intercostal spaces with 1 main dorsal perforator. It was often accompanied by a vein and an intercostal nerve cortical branch. The dorsal perforator consistently appeared 5.0–8.0 cm adjacent to the midline of the back and included both medial and lateral branches (1.0–1.6 mm in diameter). From the 4th to the 11th rib, the perforator was a direct cutaneous artery. Specifically, between the fourth and sixth rib, it anastomosed with the perforator of the CSA and the perforator of the dorsal thoracic artery/musculocutaneous perforator. Then, from the seventh to the ninth rib, the posterior intercostal artery supplied blood to the middle dorsal region.

Clinical Study

From January 2016 to December 2021, 7 women and 5 men underwent free-style perforator-based stepladder V-Y advancement flap repair. The mean patient age was 52 years (range: 34–68 y). Detailed patient information is listed in Table 2.

Table 2.

Patient Characteristics

	Sex/Age, y	Etiology	Defect Size, cm	Flap Dimensions, cm	Flap Survival	Complications	Follow-up, Mo	Sensory Grade
1	F/61	BCC	6.5 × 5.0	13.0 × 5.5	Complete	None	10	S2
2	M/68	DFSP	7.0 × 6.0	16.0 × 6.5	Complete	None	12	S2
3	M/57	SCC	8.5 × 6.5	16.5 × 7.0	Complete	None	8	S2
4	F/43	MFH	7.0 × 6.5	14.5 × 7.0	Complete	None	10	S3
5	M/45	DFSP	7.5 × 6.0	15.0 × 7.0	Complete	None	10	S3
6	M/44	DFSP	9.5 × 8.5	21.0 × 10.0	Complete	None	8	S2
7	F/36	BCC	8.0 × 7.5	16.0 × 8.0	Complete	None	12	S3
8	F/49	SCC	9.0 × 7.0	18.0 × 8.0	Complete	None	10	S2
9	F/46	DFSP	5.5 × 5.0	11.0 × 6.0	Complete	None	8	S2
10	M/35	BCC	9.0 × 6.0	19.0 × 7.0	Complete	Wound dehiscence	12	S3
11	F/56	MFH	8.5 × 7.5	16.5 × 8.0	Complete	None	10	S2
12	F/34	DFSP	8.0 × 6.0	16.0 × 7.0	Complete	Skin necrosis	10	S3

BCC, basal cell carcinoma; DFSP, dermatofibrosarcoma protuberans; MFH, malignant fibrous histiocytic carcinoma; SCC, squamous cell carcinoma.

The etiology of posterior trunk wound included resection of dermatofibrosarcoma protuberans (41.66%), basal cell carcinoma (25%), squamous cell carcinoma (16.66%), and malignant fibrous histiocytic carcinoma (16.66%). Defect areas ranged from 5.5 × 5.0 cm to 9.5 × 8.5 cm and flap areas ranged from 11.0 × 6.0 cm to 21.0 × 10.0 cm. Based on the shape, size, and blood supply of the defect, a stepped V-shaped flap was designed. The area of the step skin flap near the wound was similar to that of the recipient site, whereas the length and width of the other step skin flaps gradually decreased by about one-third from distal to proximal. To allow for primary closure of the donor area, the length of the skin flap was designed to be 2.5–3 times the length of the recipient area. There were no major complications, and all flaps survived. One patient developed necrosis of the flap tip, which was successfully treated with daily dressing changes. Sensory recovery reached the S2–S3 grade of the British Medical Research Council criteria.¹¹ Follow-up ranged between 8 and 12 months. Scar assessment using the Vancouver Scar Scale resulted in a score of 1.68 ± 0.86. There was no tumor recurrence. All patients (100%) reported satisfaction with the aesthetic outcome, and no patients reported functional limitations at follow-up.

CASE REPORT

Typical Case 1

A 68-year-old man presented to the clinic with a left chest and back mass that had been significantly enlarged with ulceration for 2 months. The preoperative pathological biopsy determined the mass to be dermatofibrosarcoma protuberans. Intraoperative frozen sections sent for rapid pathological examination confirmed negative margins. The shape of the defect was oval. The defect area was measured to be 7.0 × 6.0 cm. A stepladder V-Y advancement flap perfused by the dorsal scapular artery and the posterior intercostal artery perforator was designed to reconstruct the defect (Fig. 3A). The flap area was measured to be 16.0 × 6.5 cm. (Fig. 3B). The long axis of the flap is oriented perpendicular to the position of the long axis of the defect, with the tip facing the left scapula. The upper one-fourth of the donor site was directly approximated with sutures, whereas the lower three-fourths was sutured to the flap (Fig. 3C). The entire flap survived and was followed up for 1 year with no pain and good functional and sensory outcomes (Fig. 3D).

Fig. 3.

A, Flap design. B, Flap excision and dissection. C, Immediate postoperative flap advancement suture. D, Twelve-month postoperative follow-up.

Typical Case 2

A 44-year-old male patient presented to the clinic with a right thoracic and dorsal mass that had been present for 10 years, removed at an outside hospital 20 days prior. The preoperative pathological biopsy determined the mass to be dermatofibrosarcoma protuberans. Excision of the dorsal mass was performed under general anesthesia, and frozen sections sent for rapid pathological examination confirmed negative margins. The shape of the defect was round. The defect area was measured to be 9.5 ×8.5 cm. A stepladder V-Y advancement flap perfused by the dorsal scapular artery and the posterior intercostal artery perforator was designed to reconstruct the defect (Fig. 4A). The flap area was measured to be 21.0 × 10.0 cm (Fig. 4B). The long axis of the flap was oriented at 45 degrees to the direction of the long axis of the defect, with the tip facing the right side of the abdomen (Fig. 4C). The upper one-fourth of the donor site was directly approximated with sutures, whereas the lower three-fourths was sutured to the flap (Fig. 4D). The entire flap survived, and 1-year follow-up demonstrated no pain, good functional and sensory recovery, and excellent aesthetics (Fig. 4D).

Fig. 4.

A, Flap design. B, Flap excision and dissection. C, Flap stripping. D, Immediate postoperative flap advancement suture. E, Eight-month postoperative follow-up.

DISCUSSION

For a number of reasons, the survival rate of flaps on the back is low, and the results are often not ideal.¹² The dependent position of the back makes postoperative recovery challenging. Further, with little soft tissue elasticity and the presence of a muscular septum, flap design can be difficult.

The latissimus dorsi myocutaneous flap, trapezius flap, propeller perforator flap, and keystone flap are routinely used to repair defects of the posterior trunk.¹³ Unfortunately, all options have flaws. Although the latissimus dorsi myocutaneous flap has a width of more than 10–12 cm, direct 1-stage closure of the donor area is difficult, and skin grafting is required.¹⁴ Further, due to the high mobility of the back, it is not easy for the skin grafts to survive, and it is possible to develop problems such as scar contracture, skin ulcers, and hyperpigmentation.¹⁵ To overcome these shortcomings, Zhang et al¹⁶ reported that the "kiss" combination perforator flap could be applied to obtain a large area of latissimus dorsi myocutaneous flap while allowing direct closure of the donor area. Unfortunately, this resulted in longer surgical times.¹⁶ The trapezius flap also provides coverage to large areas, but similarly necessitates skin grafting to close the donor site and can lead to the loss of the function of the trapezius muscle, with varying degrees of shoulder and arm dysfunction.¹⁷

Although current coverage options for posterior trunk defects have abundant blood flow, the recipient site is often congested, and there is a high rate of donor site morbidity, intraoperative blood loss, and loss of function of the involved muscles after surgery.^5,18 This 2-part study demonstrated that the free-standing through-branching base trapezoidal V-Y advancement flap is a safe and reliable method of repairing posterior trunk defects without muscle sacrifice. This flap has good functional sensation, long advancement distance, and good mobility.^19–21

According to Saint-Cyr,²² a perforator preferentially perfuses the flap tissue of its same arterial origin, which in turn perfuses the neighboring area by means of a nondirect connection. We found that the perforators of the CSA, dorsal scapular artery, and posterior intercostal artery maintain consistent anatomic position, large caliber, and long vessel pedicles. Research by Ogawa et al²³ suggests that there is a vascular anastomosis between the dorsal branch of the posterior intercostal artery and the perforating branch from the CSA and the dorsal thoracic artery. Further research demonstrates that the CSA has a large blood supply area and anastomoses with the dorsal thoracic artery, the posterior intercostal artery, and the transverse cervical artery. The intrinsic blood-supplying area of the CSA is about 94 cm², and the power-supplying area is about 308 cm², which confirms the possibility of using a flap based on the perforator branch of the CSA for the repair of larger wounds on the back.²⁴ In addition, an anatomical study by Minabe and Harii²⁵ found that the caliber of the dorsal branch of the posterior intercostal artery at the point of emanation was about 1.5 mm, whereas the caliber of the perforating vessels was 0.5–1.0 mm. Dabernig et al²⁶ demonstrated that the CSA presents as a constant perforator of approximately 1.5 cm around the bifurcation of the transverse and descending branches. The constant appearance of these arterial perforations in the dorsal anatomy further proves the reliability and safety of a free-style perforator-based stepladder V-Y advancement flap using the dorsal artery as a base.

The V-Y advancement flap, a commonly used flap transfer method, is widely used in reconstructive surgery. However, the traditional V-Y advancement flap requires a longitudinal incision with aesthetically obvious and functionally limiting scarring.^27,28 This longitudinal incision can be reshaped into a “z” to mitigate these disadvantages. In this study, the flap was advanced using the “z” trapezoidal approach to minimize functional limitations, and the edges of the flap tissue were fixed with interrupted locking sutures, which made the incision easy to close and prevented scar contracture. In fact, because the stepped incisions disperse tension, the stitches can often be removed earlier than expected. Further, this shape, which creates 4 groups of interlocking triangular flaps, minimizes the force of flap recession toward the donor area.

The dorsal free-style perforator-based stepladder V-Y advancement flap has the following advantages:

1. The consistent vascular anatomy of the flap perforators, with relatively large vascular calibers and long vascular pedicles, anastomoses with the vascular perforators of the neighboring sites and can form a large vascular network associated with a large area of the flap. This allows for the flap to be designed horizontally, obliquely, or vertically.

2. This flap has abundant blood supply, and intraoperatively, it can be peeled along the perforating vessels to the source vessels to increase flap mobility, resulting in a farther advancement distance than that of the traditional V-Y flap.

3. The edges of this flap are fixed by locking interrupted suture, thereby dispersing skin tension and avoiding the formation of a restrictive linear proliferative scar. This minimizes scar contracture.

4. This flap has a long advancement distance and good mobility. This minimizes damage to the muscle and retains the accompanying cutaneous nerve when separating the vascular pedicle. This facilitates recovery of motor and sensory function postoperatively.

5. The flap is taken from nearby skin with similar skin color and texture, allowing for an aesthetically pleasing outcome.

Surgeons should be aware of the following recommendations:

1. Preoperatively, use portable ultrasound Doppler to detect the point of vascular penetration, define the location of the perforator, and design the flap with this perforator at its center.

2. Intraoperatively, microsurgical techniques should be applied to peel off the perforator vessels. The fibrous tissues around the perforating vessels should be carefully removed to increase the mobility of the flap while avoiding damage to the vessels.

3. Dissection should be gentle and meticulous to minimize damage to the flap and prevent the flap from avulsing off the deep fascia.

4. Thorough hemostasis and appropriate drain placement on the deep surface of the flap should be emphasized to prevent hematoma formation.

5. Avoid placing sutures too close together and too tightly to maintain perfusion of the flap, and always observe the flap’s blood flow during the operation.

CONCLUSIONS

The perforator-based stepladder V-Y advancement flap is a reliable and safe option for the repair of small- to medium-sized defects of the posterior trunk. Anatomical studies demonstrated consistent anatomy of the perforators of the CSA, dorsal scapular artery, and posterior intercostal artery. The stepped design of this flap disperses skin tension and avoids the formation of scar contractures. It is a well-vascularized, sensate, and pliable option, and the appearance of the flap is morphologically and functionally sound.

DISCLOSURES

The authors have no financial interest to declare in relation to the content of this article. This study was supported by the National Stem Cell Clinical Research Record Project (award ID: MR-44-21-015762), the Clinical Research Project of Affiliated Hospital of Guangdong Medical University (award ID: LCYJ2017A001), the Zhanjiang Science and Technology Development Special Fund Competitive Allocation Project (award ID: 2021A05081), and the Guangdong Provincial Medical Science and Technology Research Fund Project (award ID: A2024320).

PATIENT CONSENT

All the patients provided written consent for the publication of identifiable photographs.

ACKNOWLEDGMENT

The authors are deeply indebted to the fellows at the Department of Plastic and Reconstructive Surgery of the Affiliated Hospital of Guangdong Medical University and the fellows at the Department of Human Anatomy of Guangdong Medical University.