A Technique To Avoid a Dog-ear Deformity On the Buttock Using a “Pigeon Head” Modification of the Rotation Flap

Chronic sacral ulcers, which develop as pressure ulcers and radiation ulcers, are a well-known clinical problem and usually require surgical treatment with gluteal fasciocutaneous (FC) flaps for closure.^1,2 Recently, the superiority of gluteal perforator-based flaps in the reconstruction of sacral pressure sores has been recognized. Gluteal FC rotation flaps can still be used, especially for older patients who cannot tolerate lengthy surgeries. A distressing problem with gluteal FC rotation flaps is that a large dog-ear (Burow’s triangle) may develop on the buttock (Figure 1). The authors present a new method of avoiding a dog-ear deformity while achieving adequate repair of pressure ulcers on the buttock by using a “pigeon head” modification of the rotation flap.

Materials and Methods

Seven patients were treated using modified rotation flaps in the authors’ facility between 2004 and 2005—6 had a sacral pressure ulcer and 1 had a sacral radiation ulcer. Ages ranged from 59 to 82 years (mean age, 69 years). The size of the soft tissue defects requiring coverage following debridement ranged from 5 cm x 4 cm to 14 cm x 10 cm.
Standard surgical techniques were performed leading up to the flap elevation and included thorough cleansing and debridement of all necrotic tissues, and removal of sacral bony prominence.
The gluteal FC flap was designed to be large enough to cover the sacral defect by swinging in a wide arc. A small triangular flap was also added to the base of the arc (Figure 2A). The length of the triangular flap base was roughly 20% of the gluteal FC flap. The elevated flap is a modified bilobed flap—the small lobe resembles a bird’s beak, and the entire design resembles a pigeon’s head. The gluteal FC flap is elevated above the gluteal muscle layer and includes the small triangular flap. After the FC flap is transposed to cover the skin defect, the point of the donor site of the small triangular flap (A–A’) are pulled to meet each other and sutured—consequently, the gluteal FC flap donor site is decreased in size. The triangular flap is small enough that it can usually be transposed and sutured without removal (Figure 2B).
The patients are permitted to lie on an extra-soft, urethane foam mattress devised to fractionate pressure against the body for 2 weeks. Afterward, normal pressure on the flap from a bed or wheelchair was permitted.

Results

The pigeon head modification of the rotation flap successfully covered all 7 sacral ulcers—6 were sacral pressure ulcers and 1 was a sacral radiation ulcer. The average follow-up time was 15 months. No flap complications were observed. Immediately after surgery in all cases, Burow’s triangles were unobtrusive.

Discussion

The sacral region is the most frequent site of pressure ulcers in patients who are bedridden, and local flaps from the gluteal region are usually preferred.^2,3 The gluteus maximus muscle has been used in the treatment of sacral pressure ulcers³ however, the muscle itself is not suitable tissue for covering pressure-bearing areas. Recently, the flap most often used to cover this location is the gluteal fasciocutaneous flap, which has been used both as a perforator flap and as a rotation flap.² In particular, the use of a gluteal perforator-based flap has become a standard technique for repairing sacral pressure ulcers because this flap does not sacrifice any gluteus maximus muscle and results in no functional loss.^4,5 Since the perforators are located at various sites, they require careful dissection. Twisted perforators can sometimes cause disturbance of flap circulation, which can result in flap necrosis. For this reason, the gluteus maximus FC rotation flap, which is now considered an alternative flap, can be used because it has a short elevation time, reliable circulation, and allows for a similarly designed second flap if the ulcer should relapse. However, the flap often develops a large dog-ear on the buttock upon donor site closure, which the patient and family might find unappealing.
A rotation flap generally enables primary ulcer closure by distributing tension over wide, linear areas (Figure 3A).⁶ However, the tension against the flap sometimes disturbs flap circulation, which may cause flap necrosis (Figure 3B). To reduce tension against the flap, the outer arc of the flap donor site is pulled and sutured, which produces a distressing dog-ear deformity (Figure 3C). A pigeon head modification of the gluteal FC rotation flap consists of a general gluteal FC flap, and a small triangular flap that is located at the end of the outer arc of the flap donor site. With standard gluteal FC flaps, this triangular area of skin should be removed to repair the dog-ear deformity (Figure 4A). This modified flap was designed to include the triangular area of skin to avoid the dog-ear deformity and use it as a part of the rotation flap (Figure 4B). A diagram indicating the pigeon head modification shows that the flap margin was free from tension and laid flat without any dog-ear deformity. The only skin deformity that remained was located on the base of the rotation flap, where it was usually located near the greater trochanter (Figure 4C, 2B). This area was shaped protruded naturally so that the dog-ear was unobtrusive. This flap can also be adapted to cover relatively small defects. Figure 5 shows a case of sacral pressure ulcer measuring 5.0 x 3.0 cm that was resurfaced in the same manner with a good cosmetic result. (Figures 5A, 5B).

Conclusion

This simple technique can be performed quickly, has minimal associated morbidity, and yields a good outcome.