Robert B. Cameron, MD
Central Message.
Classifying descending necrotizing mediastinitis into Types I and II informs prognosis, but further subtyping Type II infections may only define disease stage and possibly quality measures.
See Article page 633.
Descending necrotizing mediastinitis (DNM) is a relatively uncommon but potentially fatal disease. Infections often beginning in the head/neck area quickly and aggressively spread along known anatomic planes into defined mediastinal compartments. Based on a mere 4-patient experience, Endo and colleagues1 divided DNM into 2 main categories: Type I (anterosuperior mediastinum cephalad to the carina) and Type II (lower mediastinum). They further subdivided the lower mediastinal infections into Type IIA (anterior lower) and Type IIB (anterior and posterior lower). With such limited numbers, the only appropriate conclusion was that DNM classification might standardize required drainage procedures, although admittedly computed tomography scans exclusively determined drainage targets.
Sugio and colleagues2 collated an impressive number of DNM cases (n = 225) over a 5-year period from 131 participating institutions with both cervical and thoracic expertise as part of a jointly sponsored Japanese study (JBES1703/JACS1806). Extensive cataloging of microbiology results and both initial and reoperative surgical approaches are presented in detail. Analysis of the copious data at times becomes overly complex, such as correlating the anterior pre-/paratracheal and the posterior prevertebral anatomic planes of cervical-mediastinal infection spread. Further, the mortality analysis notes a 30-day mortality of 3.6% (8 patients) and a 90-day mortality of 5.3% (12 patients), which are both outstanding. But surprisingly, later only 7 (of all 28) deaths during the entire 3- to 5-year follow-up period are attributed directly to DNM. Using a logistic regression model, the authors clearly show that Type II (vs Type I) infections were associated with a greater 90-day mortality (odds ratio, 4.63; P = .034); age also adversely influenced survival. With this large dataset, an additional DNM class type not previously specifically reported was recognized in 43 patients (34.4%) with superior and only posterior lower mediastinal involvement termed Type IIC. This simple extension of the prior classification system (not a truly new system as the article title implies) curiously revealed that these Type IIC infections were more amenable to transcervical drainage, thus requiring fewer thoracotomies than other Type II infections. Additional interesting information regarding the Type II subtypes then stops. For instance, Sugio and colleagues'2 Table E6 shows no 90-day mortality differences between any Type II infections. Frustratingly, the 30- and 90-day mortality numbers are grouped simply into Type I and II (1 out of 2 and 7 out of 10, respectively) without detailed subtype distribution differences. This raises a fundamental question: Is there any utility to the subdivision of Type II patients? Perhaps only Type I and II DNM types should exist, merging/grouping subtypes with similar outcomes—following a rationale similar to that used for TNM stage groupings in lung cancer. Perhaps, the only clear potential use for Type II subgroups is to provide a DNM stage-based guideline and quality measure for identifying and measuring appropriate computed tomography-confirmed surgical drainage targets and procedures (Table 1). In this instance, I favor designating Type I and Types IIA (anterior), IIP (posterior), and IIAP (anterior and posterior) as intuitive. With their extensive dataset, perhaps the authors will extend their analysis to the next level and address some of these additional areas.
Table 1.
Sample surgical quality measures based on descending necrotizing mediastinitis class/stage
| Class/stage | Procedures |
||||
|---|---|---|---|---|---|
| Gold standard | Acceptable alternate | Acceptable alternate | Acceptable alternate | Borderline/suboptimal | |
| Class/stage I | Cervicotomy (Bilateral) | Cervicotomy (Unilateral) | None | None | Percutaneous image-guided drainage |
| Class/stage II | |||||
| IIA | Cervicotomy (bilateral) with Subxiphoid debridement/drainage | Cervicotomy (unilateral) with Subxiphoid debridement/drainage | Cervicotomy (uni- or bilateral) with Bilateral thoracoscopic drainage | Cervicotomy (uni- or bilateral) with Bilateral thoracotomy with drainage | Cervicotomy alone |
| IIB Alternate: IIA/P | Cervicotomy (uni- or bilateral) with bilateral thoracotomy and drainage | Cervicotomy (uni- or bilateral) with bilateral thoracoscopic drainage | Cervicotomy (uni- or bilateral) with unilateral thoracotomy and drainage | Cervicotomy (uni- or bilateral) with unilateral thoracoscopic drainage | Cervicotomy (uni- or bilateral) with simple uni- or bilateral tube thoracostomy |
| IIC Alternate: IIP | Cervicotomy (uni- or bilateral) with bilateral thoracotomy and drainage | Cervicotomy (uni- or bilateral) with bilateral thoracoscopic drainage | Cervicotomy (uni- or bilateral) with unilateral thoracotomy and drainage | Cervicotomy (uni- or bilateral) with unilateral thoracoscopic drainage | Cervicotomy (uni- or bilateral) with simple uni- or bilateral tube thoracostomy and other lower mediastinal drain(s) |
Footnotes
Disclosures: The author reported no conflicts of interest.
The Journal policy requires editors and reviewers to disclose conflicts of interest and to decline handling or reviewing manuscripts for which they may have a conflict of interest. The editors and reviewers of this article have no conflicts of interest.
References
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- 2.Sugio K., Okamoto T., Maniwa Y., Toh Y., Okada M., Yamashita T., et al. Descending necrotizing mediastinitis and the proposal of a new classification. J Thorac Cardiovasc Surg Open. 2021;8:633–647. doi: 10.1016/j.xjon.2021.08.001. [DOI] [PMC free article] [PubMed] [Google Scholar]