Narrative review of descending necrotizing mediastinitis, focusing on the etiology, classification-guided surgical management, treatments, and prognosis.

Background and Objective: Descending necrotizing mediastinitis (DNM) is a rare, life-threatening infection characterized by the rapid spread of deep neck infection (DNI) along the continuous fascial planes into the mediastinum. Although diagnostic and therapeutic advances have improved patient outcomes, the prognosis remains unsatisfactory in advanced cases or in the absence of timely and appropriate treatment, mainly due to delayed diagnoses and difficulty in selecting an appropriate surgical approach. This review summarizes the current knowledge on the pathophysiology, anatomical classification, and surgical treatment of DNM, with particular emphasis on a recently proposed classification for surgical planning. Methods: A literature search was conducted using PubMed/MEDLINE for the period from January 1999 to June 2025 with the term "descending necrotizing mediastinitis". Full texts were retrieved through the Oita University Library. No restrictions were placed on article type. Eligible studies were English-language reports (written in English at least in abstract) addressing the etiology, pathophysiology, anatomical classification, surgical approach and treatment, or outcome of DNM. Conference proceedings and animal experimental studies were excluded. For quantitative tabulations, only articles reporting ≥4 patients were included, and less than 4 patients case-reports were excluded from the quantitative summaries. Key Content and Findings: Over time, disease classification has become more common, and the proportion of Type I disease has been increasing, reflecting improvements in the early diagnosis. Mortality rates have improved from 24.7% in the 2000s to 17.8% in the 2010s and to 14.1% in the 2020s, in our descriptive rates derived from registry cohorts. Type II disease extending below the carina, is associated with worse outcomes than Type I disease. In particular, Type IIC disease descending through the retrovisceral space, is often unsuitable for traditional anterior approaches and requires a posterior mediastinal approach via video-assisted thoracic surgery (VATS). Optimal outcomes depend on a multidisciplinary treatment strategy that includes early airway management, broad-spectrum antimicrobial therapy, and precise targeted surgical drainage. Conclusions: Improved treatment outcomes for DNM require a rapid diagnosis, accurate anatomical assessment, and prompt, case-appropriate surgical intervention. Recognizing the correct classification enables the selection of the most suitable drainage approach and is expected to further improve the prognosis.