Velopharyngeal insufficiency (VPI) is a known complication of transoral surgery, with a reported incidence of 8.1%. The main factor related to VPI is the split of the soft palate. However, dead space resulting from transoral decompression may play a pivotal role in the pathogenesis of the dysfunction. In our experience, functionally significant dead space is almost constantly present after transoral decompression. This is probably due to malformation in children and postoperative scarring, thus configuring a nosological entity that we could define as "syndrome of the nasopharyngeal dead space." Palatal prosthesis and pharyngoplasty have been proposed, though these surgical procedures are technically tricky and with possible complications, such as OSA symptoms, snoring, and nasopharyngeal stenosis. We proposed an effortless and minimally invasive procedure to treat this condition based on lipofilling the nasopharynx posterior wall endoscopically. To test the procedure's functional result, the submucosa of the nasopharynx posterior wall was initially filled with resorbable material, namely fibrin glue and autologous blood. The result was optimal but regressed after one month. Then, we repeated the procedure by lipofilling with autologous abdominal fat, resulting in a more stable anatomical and functional outcome at six months follow-up. The patient had a prompt significant improvement of his complaints (rhinolalia and oronasal regurgitation) and a correct projection of the nasopharynx posterior wall, with correct closure during phonation and absence of oronasal reflux. The "syndrome of the nasopharyngeal dead space" should be correctly identified after transoral surgery. It can be effectively treated with lipofilling of the posterior nasopharyngeal wall, a simple and minimally invasive procedure.