Keystone-design perforator island flaps for the management of complicated epidermoid cysts on the back.

Complicated epidermoid cysts (ECs) occur commonly on the back, but few reports have described their management. We present our experience in managing patients with ECs on the back using a keystone-design perforator island flap (KDPIF) reconstruction, thereby focusing on reduction and redistribution of wound tension. Altogether, 15 patients (average age, 48.067 ± 14.868 years) underwent KDPIF reconstructions after complete excision of complicated ECs on the back. We retrospectively reviewed the medical records and clinical photographs of all patients. Final scar appearance was evaluated using the Patient and Observer Scar Assessment Scale (POSAS). All patients had ruptured ECs, while 6 patients also had cellulitis of the surrounding tissues. All defects, after complete excision of ECs and debridement of surrounding unhealthy tissues, were successfully covered with KDPIF. The mean 'tension-change' at the defect and donor sites was -4.73 ± 0.21 N and -4.88 ± 0.25 N, respectively (p < 0.001). The mean 'rate of tension-change' at the defect and donor sites was -69.48 ± 1.7% and -71.16 ± 1.33%, respectively (p < 0.001). All flaps survived with no postoperative complications. The mean observer scar assessment scale (OSAS) summary score and patient scar assessment scale (PSAS) total score were 14.467 ± 5.069 and 15.6 ± 6.512, respectively. Overall, we suggest that KDPIF reconstruction is a good surgical modality for the management of complicated ECs on the back.