When There Is Necrosis Of A Bilobed Transposition Skin Flap

In a case study involving post-op necrosis in a 59-year-old patient with a chronic wound, these authors emphasize a sound understanding of proper surgical techniques with rotational flaps as well as the vascularity in the area to help prevent complications.

Rotational flaps are useful in repairing defects secondary to chronic wounds, diabetic ulcers, malignant lesions and callosities. The bilobed flap can effectively transfer tension across a larger angle of rotation and thus distributes the load more evenly. With this in mind, let us take a closer look at the use of a bilobed transposition flap to help heal a wound plagued by chronic recurrence for five decades.

A 59-year-old female with no significant past medical history sustained a chronic anterior left lower extremity wound after a motor vehicle accident when she was nine years old. Over the last 50 years, she had continous episodes of recurrence and reopening of the wound. In 2018, the patient had a split-thickness skin graft but the graft failed as she had recurrence of the wound six months later. She initially presented to the wound clinic in September of 2018 with a 1.9 cm x 1.5 cm wound that extended down to the level of subcutaneous tissue. The patient was applying collagenase (Santyl, Smith and Nephew) ointment to the wound with a dry dressing. After weekly wound clinic visits for nine months with continued wound recurrence, we decided to utilize a transpositional flap to fill the deficit. 

Upon taking the patient to the operating room, we palpated the surrounding skin and soft tissue to evaluate for elasticity, and determine the most optimal donor site. It is important to evaluate the donor site for tissue mobility and elasticity to avoid tension of the flap after relocation. We decided to proceed with a bilobed transpositional flap. We first excised the wound to create a circular defect measuring 2 cm x 2 cm. The ulcer extended to bone, which prompted a bone biopsy sample for a pathology exam. We then outlined a bilobed flap with a skin marker at the lateral aspect of the defect with the medial lobe being 75 percent of the defect width and the lateral lobe being 50 percent of the width of the defect. We left a pedicle to the flap in place to allow for continued vascularity. We proceeded to dissect the flap full thickness with the attached subcutaneous layer and rotated it toward the defect using atraumatic forceps. Simple sutures with 4-0 prolene secured the flap. The surgical dressing consisted of non-adherent gauze and a dry sterile dressing.

At the first postoperative visit, we noted necrosis to a small portion of the bilobed flap, which prompted a referral for hyperbaric oxygen therapy (HBOT). The patient had HBOT four times a week along with regular wound clinic appointments. In the wound center, we debrided and excised the necrotic portion of the flap. Dressing applications consisted of silver alginate and dry dressings. The previous bone biopsy was negative for osteomyelitis. After two months of HBOT, the patient’s wound ultimately healed four months after the initial surgery with the bilobed transposition flap.

Keys To AddressIng Flap Necrosis

It is important to understand the surgical techniques in utilizing rotational flaps as well as knowing the vascularity. The bilobed flap is both a rotational and transpositional flap. One of the most common complications of both transpositional and rotational flaps is flap necrosis. In this case, the patient presented with partial necrosis to the bilobed flap two weeks after the procedure. Tissue necrosis can cause hypoxia, which can subsequently lead to infection.

Hyperbaric oxygen therapy is an adjuvant treatment in which patients breathe 100 percent oxygen in an enclosed hyperbaric chamber. This allows for increased oxygenation to the areas of necrosis, which in turn controls infection, reduces inflammation and promotes angiogenesis. In this case involving a nonviable portion of a rotational skin flap, we found that HBOT was successful in a 4-month postoperative follow up. 

In Conclusion

After reviewing the surgical technique for the aforementioned patient, we found that the most important things to keep in mind when doing a skin flap are recognition of locations of angiosomes, atraumatic technique and careful measurement of the defect with the overlying flap. Flap necrosis is common but one can treat this with a combination of proper wound care and HBOT. 

Dr. Pokala is a second-year podiatry resident at Providence Park Hospital in Southfield, Mich.

Dr. Belken is board-certified by the American Board of Podiatric Medicine and is in practice in Livonia, Mich.

1. Zgonis T. Surgical Reconstruction of the Diabetic Foot and Ankle. Philadelphia:Wolters Kluwer;2018.

2. Starkman SJ, Williams CT, Sherris DA. Flap basics I. Facial Plast Surg Clin North Am. 2017;25(3):313–321. 

3. Semadi IN. The role of VEGF and TNF-Alpha on epithelialization of diabetic foot ulcers after hyperbaric oxygen therapy. Open Access Macedonian J Med Sci. 2019;7(19). Available at: https://www.id-press.eu/mjms/article/view/oamjms.2019.297 . Published August 20, 2019. Accessed February 24, 2019.