A Covered Lateral and Posterior Wall Flap of the Maxillary Sinus Prevents Reocclusion of the Postoperative Maxillary Cyst

Although the number of postoperative maxillary cyst (POMC) cases has declined recently, a few reports of refractory cases have also been reported. The indications for endoscopic sinus surgery (ESS) for POMC removal are broadening and attempts to prevent postoperative recurrence at the cyst opening site have been widely investigated. Here, we have advocated our original pedunculated mucoperiosteal flap (CLAP flap; covered lateral and posterior wall flap of the maxillary sinus), where the bony area exposed intraoperatively is covered, to prevent postoperative recurrence. We have also presented the method for creating the CLAP flap. We classified the POMC as being medial, lateral, or anterior superior type and performed ESS. We introduced the CLAP flap after 2015 for the lateral type and some of the medial types of POMCs. We examined the cyst opening rate using computed tomography, age, sex, cyst position, and a follow-up period in four patients (five sides) who did not undergo flap surgery, but who were managed in our hospital in 2015, and in eight patients (nine sides) who underwent the CLAP flap technique in our hospital. In the group with the CLAP flap, the cyst opening rate was significantly higher (P < 0.05). The CLAP flap was effective for preventing postoperative bony regrowth. It may be one of the options for covering the exposed bone surface as widely as possible.