Odontogenic Retropharyngeal Space Abscesses: Incidence and Distinctive Features From a Multi-Institutional Cohort of 145 Patients.

Odontogenic retropharyngeal abscess is an extremely rare but life-threatening infection. The authors aimed to investigate their incidence and characteristics by collecting data in the multicenter. This study included 145 patients who had mandibular odontogenic-origin deep neck abscesses at 5 hospitals in Japan. First, to them, the ratio of patients who had retropharyngeal spaces abscesses was investigated. Next, their characteristics were analyzed by comparing with those who had parapharyngeal or pterygomandibular space abscesses, which did not extend to the retropharyngeal space. Of all patients, 4 (2.8%) were included in the retropharyngeal group (R group) and 35 (24.1%) were involved in the parapharyngeal or pterygomandibular group (PP group). Although all patients in the R group had both parapharyngeal and pterygomandibular space abscesses, only 22.9% (8/35) of the PP group had them both, a significant difference ( P =0.006). All patients in the R group required tracheostomy, whereas none in the PP group required tracheotomy ( P <0.001). Despite the rarity of odontogenic retropharyngeal space abscesses, our study is the first to characterize their features through comparative analysis within a larger cohort. The presence of retropharyngeal space abscesses may be an important indicator of respiratory-threatening spread of infection and the need for tracheotomy.