Melero Sancho et al  reported the data of 7 patients, hospitalised between 1986 and 1997, affected by DNM, due to oropharyngeal infections (57% odontogenic infections, 43% peritonsillar abscess). Every patient was treated by bilateral cervicotomy, debridement and excision of necrotic tissue and a mediastinal drainage (4 transparietal drainage, one via sternotomy, one via thoracotomy, one via mediastinotomy). The authors concluded that DNM, early diagnosed by clinical and radiological signs, required an ample cervicotomy with mediastinal drainage, generally associated with thoracotomy. This surgical approach could significantly reduce the mortality rate.
Marty-Ane’ et al , reported a 10 years’ experience about DNM, consistingin 12 patients. The primary oropharyngeal infection was a peritonsillar abscess in 7 patients and an odontogenic abscess in 5 patients. The treatment proposed was bilateral cervicotomy in every patients, followed by a thoracotomic debridement and drainage in 11 cases and mediastinotomy and mediastinal drainage in one case. Author finally stated that, in patients with very limited disease to the upper mediastinum, transcervical mediastinal drainage alone, was justified. For all the rest of patient with clinical or radiological signs of mediastinal infections or sepsis, drainage through a major thoracic approach, was required.
Freeman et al  reported the experience of 10 patients, in whom, descending necrotizing mediastinitis was identified. After radiological diagnosis by X-ray and CT scan, 5 patients was treated by transcervical drainage procedures, 3 by transthoracic drainage procedures. Three patients required abdominal exploration and 4 underwent tracheostomy. This paper clearly shows that, computed tomographic imaging for diagnosis and following serial transcervical and transthoracic operative drainages, are recognized such as correct algorithm in treatment of DNM.
Makeieff et al , analysed pre and postoperative outcomes of 17 patients, hospitalised in a single centre. DNM was due to pharyngitis (6 cases), peritonsillar abscess (3 cases), dental abscess (6 cases), foreign body infection (1 case), and laryngitis (1 case). Mean clinical manifestations duration before diagnosis, was 6 days. Only three cases performed the cervicotomy followed by the cervical and mediastinal drainage. In 14 other cases, a thoracotomic approach, with pleural and mediastinal cavity cleaning and debridement, was performed. Authors concluded that, correct surgical choice (usually thoracotomic approach with debridement and mediastinal and pleural drainage), corroborated to correct medical management in an intensive care unit, may significantly reduce the mortality rate to less than 20%. Similar data have been reported by Papalia et al.  and Mihos et al. .
Inoue et al  showed his series of patients, affected by DNM in the period between 1996 and 2004. Peritonsillar (77%) and odontogenic (23%) abscess were the originating incectious foci. Authors classified DNM in localized (infection localized to the upper mediastinum above the level of the carina) and extensive (infection extending to the lower mediastinum beyond the level of the carina). All patients underwent to surgical mediastinal drainage. In patients affected by extended DNM, simple mediastinal drainage was corroborated by a more aggressive approach and transthoracic drainage by right VATS or right thoracotomy. Authors suggested possibility of mediastinal surgical drainage alone, in limited DNM, and necessity of thoracoscopic or thoracotomic approach in extended DNM.
Iwata et al  analysed the data of 10 patients, treated in Inohana hospital. The causes of DNM were primary peritonsillar or parapharyngeal abscess (5 patients), odontogenic abscess (3 patients), one post-tracheostomy cervical abscess. One patient rested without primary diagnosis of infection spread. In this report, for the first time, authors based the treatment on extension-severity’s classification of Endo, in order to definy limited or extended DNM. Nine patients presented an extended disease, with signs of infection until to posterior lower mediastinum. Surgical treatment consisted in cervical drainage, debridement and excision of necrotic tissue in the mediastinum and pleural decortication, via thoracotomy. Post-operative antibiotics irrigation with saline were performed in all cases, until negativizing of pleural liquid culture. 8 patients were discharged without post-operative complications and the mortality rate was 20%. Authors, thus recommended this combined surgical and medical treatment, regardless of extended or limited DNM.
Misthos et al  evaluated 27 patients, affected by DNM and treated between 1985 and 2002. All patients presented previous cervical phlegmon. According to Endo classification , patients were distributed into two groups, receveing different treatment. Specifically, patients with infection involving mediastinal tissue, until tracheal carena (group I classification Endo), underwent the combined transthoracic mediastinal and cervical drainage. Patients with extended DNM (group II classification Endo) underwent the debridement of any necrotic or infectious mediastinal tissue and the wide opening of mediastinal pleura, via lateral thoracotomy (the same side as the pleural effusion). In addition, they underwent the cervical drainage, via anterior cervical incision for performing debridement and excision of necrotic neck’s tissue. The authors suggestion was that early combined thoracic and cervical approach could represent the treatment of choice for DNM.
Chen et al  showed Taiwan’s experience (18 patients) in management of DNM. Odontogenic abscess (2 cases), peritonsillar or retropharyngfeal abscess (9 cases), presence of foreign bodies (3 cases) and acute epiglottis (3 cases) represented the primary infection focus. Surgical treatment for limited disease (11 patients) consisted in anterior cervicotomy with opening, draining and debridement of necrotic neck’s tissue. A subsequent mediastinal drainage was posed via mediastinoscopy, VATS or subxiphoid access. Extended disease (7 patients) was treated by debridement of the mediastinum and pleura, excision and decortication of necrotic tissue and adequate placement of silicone drains or chest tubes. Chen concluded that simple mediastinal drainage was justified, only in the limited disease. For extended disease, an additional subxiphoid approach is suggested for anterior mediastinal involvement, while video-assissted mediastinal drainage is suggested for posterior mediastinum and pleural space.
Lanisnik et al  analysed descending necrotizing mediastinitis following to necrotizing fasciitis of the head and neck. In 17 of 34 original patients with necrotizing fasciitis, it was diagnosed DNM. Here too, authors adapted surgical treatment to topographic localization of infectious focus. For DNM limited to upper mediastinum, until tracheal carena, (group I) it was performed a transcervical incision with mediastinum drainage and the chest tube positioning. For the diseases extended to lower anterior mediastinum (IIA), cervical drainage was completed by a transcervical mediastinum drainage; for disease extended to lower anterior and posterior mediastinum, it was performed a lateral thoracotomy in addition to cervical and mediastinal drainage. Finally authors remarked importance of early and accurate diagnosis for a correct therapeutic choice.
Thirteen patients were included in the report of Sokouti et al . 10 cases had Mediastinal infection derived by odontogenic abscess and 3 cases had peritonsillar and retropharyngeal abscess. 8 patients underwent cervical drainage and thoracotomy, and 5 patients were treated by cervical drainage and mediastinotomy. Here too, authors underlined the importance of an early diagnosis.
Karkas et al  reported an experience of 17 patients with DNM. In ten patients, DNM was located above the carina and could be accessed by a cervical approach. In seven patients, DNM was below the carina. Particularly, patients with an anterior involvement were treated by sternotomy; those with posterior involvement were operated via postero-lateral thoracotomy. Authors finally drafted a therapeutic algorithm for the postoperative management of DNM.
A large series of DNM patients is reported by Deu-Martin . 43 patients with a clinical and radiological diagnosis of DNM, deriving from head and neck infections, were enrolled. Surgical treatment was determined according to topographic classification of Endo. Authors analysed risk factors associated to DNM. Using bivariate and multivariate analysis, it emerged that age >66 years, associate comorbidities and diagnostic period (antecedent to 2000) represented the risk factors for post-surgical death. Finally they focused on early diagnosis and on necessity of multidisciplinary treatment.
Hsu et al  compared simple transcervical drainage alone for group 1 (limited disease) to integrated treatment (cervical and thoracic) for group 2 (extended disease). No difference in terms of post operative complications or death was observed but authors concluded that an aggressive, transcervical mediastinal drainage, associated to thoracic debridement is fundamental for a good outcome.
Ridder et al.  described another large series of patients. Author analysed 45 cases of DNM and he compared his results with those resulting from a meta-analysis of 26 studies. The primary infection foci were pharyngeal infection, primary neck infection, odontogenic infection, ingested foreign bodies, iatrogenic pharyngeal perforation and iatrogenic catheter infection. All patients received cervicotomy for treating original infectious focus and trans-cervical drainage of the mediastinum. In only 7 patients a transthoracic approach to drain pleural cavity was performed (5 posterolateral thoracotomy, 1 subxiphoid approach and 1 sternotomy). Ridder concluded affirming that the formal thoracotomy should be reserved for cases extending below the plane of the tracheal bifurcation, according to Endo classification.
Wakahara et al  reported their experience, evaluating 11 patients with DNM. In all cases, regardless to severity of disease, patients were treated by an aggressive approach: cervical drainage by cervicotomy and subsequent lateral mini-thoracotomy or thoracoscopy (if possible), with toilette, debridement and decortication of infectious and necrotic tissue. Mortality rate was 0%. Authors finally recommended this approach in management of DNM.
Kocher et al  analysed surgical therapy and outcomes in DNM “Endo type II”. All 16 patients affected by DNM, were treated by an aggressive approach, 8 via sternotomy, 8 via clamshell. In addition, authors analysed risk factors in their population and they concluded that diagnostic-therapeutic delay (>15h from beginning of symptoms) represented a very important aspect to consider in the correct management. D’Cunha et al  proposed a cervical debridement for 8 patients admitted at Minneapolis Hospital. Guan et colleagues  examined two surgical treatments for DNM, involving anterior mediastinum (cervical drainage+ trans-cervical or transthoracic mediastinum drainage versus cervical drainage + bilateral thoracoscopy via sub-xiphoid access). 15 patients were enrolled and authors concluded that in these cases treatment by trans-cervical mediastinal drainages were possible. If mediastinitis spreads to the side of the trachea, an appropriate therapy is represented by open thoracotomy. If the entire anterior mediastinum is involved (over the trachea), cleaning and debridement should be performed with a thoracoscope via the subxiphoid incision.
Dajer-Fadel et al  reported the largest series in the literature on DNM. 60 patients were enrolled in this study during a 7-years period. All the patients underwent the drainage of three mediastinum compartment (upper, lower anterior and posterior) via postero-lateral thoracotomy, in order to debride and decorticate necrotic tissue of one or both pleural cavity and mediastinum. Authors analysed risk factors for mortality and they concluded that age and diabetes were the most important risk factors, but, not for last, the socioeconomic level.
The only prospective study included in our review is the report of Palma et al . Authors prospectively examined all patients with DNM admitted to the Intensive Care Unit. 34 patients were admitted and they were treated by trans-cervical drainage in DNM type I (14 cases, 42 %); patients affected by DNM type IIA (ten cases, 29 %), was treated by the anterior mediastinum irrigation through sub-xiphoid and cervical incisions, with additional percutaneous thoracic drainage when necessary; thoracotomy with radical mediastinal surgical debridement, excision of necrotic tissue and decortication was performed for patients affected by DNM type IIB (ten cases, 29 %). In addition, they founded an important correlation (p=0,03) between time to Intensive care unit admission after head and neck infection and pathological score (SAPS II score). Authors finally underlined the importance of an early assistance, aggressive surgery, and adequate antibiotic therapy for reducing mortality rate in DNM.
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