Outcomes of the keystone perforator island flap for oncologic reconstruction of the back

Background: Coverage of posterior trunk defects after tumor resection can be challenging due to the intricate anatomy. The keystone perforator island flap (KPIF) provides coverage of the defect without the need for distant flap coverage or microsurgery, matches the recipient's skin color and contour, and requires a short operative time. Methods: A retrospective review of all oncological back reconstructions with KPIF was performed at our institution. The patient comorbidities and surgical outcomes were collected. Results: A total of 17 patients underwent 20 KPIF (15 single and 2 double) for back reconstruction. Surgical indications were sarcoma (n = 12) and melanoma (n = 5). The mean age at surgery was 47.3 years (SD 23.3). The flaps were located in the upper back (n = 8), paraspinal (n = 4), middle back (n = 6), and lower back (n = 2). The average wound size after sarcoma and melanoma excision were 231.6 ± 297.4 and 156.7 ± 269.7 cm², respectively. Four patients required an additional planned skin graft and one patient underwent a simultaneous myocutaneous latissimus dorsi flap. The mean operative time, including tumor resection, was 256 min (SD 118). The median length-of-hospital stay was 3 days (Q1–3: 1–6.5) and the median follow-up time was 35.3 months (Q1–3: 13.3–53.1). All flaps survived with minor surgical complications which included hematoma (n = 1), surgical site infection requiring debridement (n = 1), superficial wound dehiscence (n = 1), cellulitis (n = 1), and seroma (n = 1). The reconstructions were successful in 100% of patients. Conclusions: The KPIF is a reliable and safe option for reconstruction of oncological back defects with minimal perioperative complications. This flap option avoids the use of free flaps and myocutaneous flaps for moderate-sized back defects.