Improved staging using intraoperative ultrasound for mediastinal lymphadenectomy in non-small lung cancer surgery

BackgroundExtent of lymph node involvement in patients with non-small cell lung cancer (NSCLC) is the cornerstone of staging and influences both multimodality treatment and final outcome. The aim of this study was to investigate accuracy and characteristics of intraoperative ultrasound guided systematic mediastinal nodal dissection in patients with resected NSCLC.MethodsFrom January 2008 to June 2013, 244 patients undergoing intraoperative surgical staging after radical surgery for NSCLC were included in prospective study. The patients were divided in two groups according to systematic mediastinal nodal dissection: 124 patients in intraoperative ultrasound nodal dissection guided group and 120 in standard nodal dissection group. The lymph nodes were mapped by their number and station and histopathologic evaluation was performed.ResultsOperating time was prolonged for 10 min in patients with ultrasound guided mediastinal nodal dissection, but number and stations of evaluated lymph nodes were significantly higher (p < 0.001) in the same group. Skip nodal metastases were found in 24% of patients without N1 nodal involvement. Twelve (10%) patients were upstaged using US guided mediastinal lymphadenectomy. In US guided group 5-year survival rate was 59% and in the group of standard systematic mediastinal lymphadenectomy 43% (p = 0.001) Standard staging system seemed to be improved in ultrasound guided mediastinal lymphadenectomy patients. Complication rate showed no difference between analyzed groups.ConclusionHigher number and location of analyzed mediastinal nodal stations in patients with resected NSCLC using ultrasound is suggested to be of great oncological significance. Our results indicate that intraoperative ultrasound may have important staging implications.     

Hard-shell cardiotomy reservoir for reinfusion of shed mediastinal blood

We conducted a prospective, randomized, controlled trial comparing homologous blood consumption between groups of patients receiving conventional mediastinal drainage (group 1) or reinfusion of shed mediastinal blood (group 2) using hard-shell cardiotomy reservoir. One hundred consecutive patients who had elective coronary artery or valvular operations were studied. The two groups were comparable with regard to age, sex, weight, preoperative and postoperative hemoglobin levels, and surgical procedure. Group 2 patients had their shed mediastinal blood reinfused for up to 18 hours postoperatively; otherwise, the two groups were treated identically. For groups 1 and 2, average mediastinal blood losses were 705 +/- 522 and 822 +/- 445 mL and homologous blood consumption was 3.83 +/- 2.58 and 3.15 +/- 2.05 U, respectively (neither measure was significantly different). However, if blood losses exceeded 500 mL, there was a statistically significant reduction in homologous blood requirements in group 2 as compared with matched controls in group 1. This difference was most significant in patients with the greatest mediastinal losses.     

达芬奇机器人与电视胸腔镜治疗纵隔神经源性肿瘤的对比研究

目的探讨和比较达芬奇机器人手术(robot-assisted thoracoscopic surgery,RATS)、电视胸腔镜手术(video-assisted thoracoscopic surgery,VATS)治疗纵隔神经源性肿瘤的临床结果。 方法回顾性分析2015年7月至2019年12月期间,解放军总医院微创手术治疗的95例MNT患者临床病理资料,比较RATS、VATS的临床治疗结果。 结果RATS组31例,VATS组64例,均实现R0切除,两组基线资料差异无统计学意义(P>0.05);术中出血量、术后引流量、术后并发症发生率方面,差异无统计学意义(P>0.05)。RATS组手术时间长于VATS组,但术后引流管留置时间、术后住院时间显著低于VATS组,差异有统计学意义(P<0.05)。 结论RATS是治疗MNT安全、可行的手术方式,相比于VATS,患者术后恢复更快。     

Spontaneous regression of anterior mediastinal seminoma with normalization of β-human chorionic gonadotropin levels

IntroductionAlthough spontaneous regression (SR) of anterior mediastinal seminoma is very rare with normalization of β-human chorionic gonadotropin (β-hCG) level, video-assisted thoracic surgery (VATS) is the most effective solution for definite diagnosis of indeterminate anterior mediastinal masses.Diagnosis, therapeutic interventions, and outcomesA rare case of an asymptomatic 37-year-old man with an anterior mediastinal mass that was detected on a routine chest X-ray is presented. Computed tomography (CT) showed a large anterior mediastinal tumor with superior vena cava invasion and SR before VATS for definitive diagnosis. On pathology, the definitive diagnosis was seminoma. Microscopic examination showed abundant apoptotic cells within the tumor. Chemotherapy (bleomycin 30 mg/day, etoposide 200 mg/day, cisplatin 40 mg/day) was given to this patient, and the tumor showed high sensitivity.ConclusionAnterior mediastinal seminoma showing SR induced by spontaneous apoptosis of tumor cells may have good sensitivity to chemotherapy, and a good clinical outcome may be achieved in these patients. This case also highlights that VATS is the most effective solution for definite diagnosis of indeterminate anterior mediastinal masses.     

Prostate cancer incidence and survival in immigrants to Sweden

Purpose

The large international variation in the incidence of prostate cancer (PC) is well known but the underlying reasons are not understood. We want to compare PC incidence and survival among immigrants to Sweden in order to explain the international differences.

Methods

Cancer data were obtained from the Swedish Cancer Registry. Standardized incidence ratios (SIRs) were calculated for PC in first-degree immigrants by country of birth. The immigrants were classified into four groups by SIR and area of origin. Survival in PC was assessed by hazard ratio (HR) in the four groups. In some analyses, clinical stage of PC was assessed by the tumor, node, and metastasis classification.

Results

The SIR was 0.47 (95 % confidence interval 0.43–0.51) for immigrants with the lowest risk, constituting men from Turkey, Middle East, Asia, and Chile. The HR was 0.60 (0.45–0.81) for these men and it was 0.49 if they had stayed 20+ years in Sweden. The SIR in screening detected PC, T1c, was 0.55. Among these men, screening detected PC constituted 34.5 % of all PC, compared to 29.0 % among Swedes (p = 0.10).

Conclusions

The results showed that the non-European immigrants, of mainly Middle East, Asian, and Chilean origin, with the lowest risk of PC, also had the most favorable survival in PC. As the available clinical features of PC at diagnosis or the distribution of known risk factors could not explain the differences, a likely biological mechanism through a favorable androgenic hormonal host environment is suggested as an explanation of the observed effects.     

Easier node dissection after chemoradiotherapy for lung cancer with collagen insertion at mediastinoscopy

Objective: Induction chemoradiotherapy followed by anatomical resection is a current therapeutic strategy for non-small-cell lung cancer with mediastinal node involvement. Dense peritracheal fibrosis and sclerosis after chemoradiotherapy cause difficult mediastinal node dissection. We evaluated a novel technique to make the mediastinal node dissection easier after induction therapy. Methods: At the end of mediastinoscopic node biopsy for staging of lung cancer, cotton-type collagen was inserted anterior and lateral to the trachea in patients with pathologically confirmed mediastinal node involve-ment (n=45). The induction therapy consisted of concurrent use of platinum-based chemotherapy and hyperfractionated radiotherapy. After the chemoradiotherapy all patients underwent a pulmonary resection with complete mediastinal node dissection 7–12 weeks after the collagen insertion. Surgical findings of the mediastinum and the time for node dissection were compared with those without collagen insertion at mediastinoscopy after chemoradiotherapy (n=5). Results: All five patients without collagen insertion showed sclerotic and fibrotic change of mediastinal nodes with severe adhesion to the trachea. In 42 of 45 patients with collagen insertion (93.3%) the collagen remained unabsorbed and separated the mediastinal nodes from the trachea. Mediastinal node dissection was easily accomplished by removing mediastinal tissues lateral and anterior to the collagen. The rate of mediastinal node separation was significantly higher with collagen insertion than without (p< 0.0001). The times for node dissection in patients with and without collagen insertion showed no significant difference. Conclusion: Cotton-type collagen insertion at staging mediastinoscopy for lung cancer separates the mediastinal nodes from the trachea and makes the node dissection easier after induction chemoradiotherapy.     

Mediastinoscopy vs. anterior mediastinotomy in the diagnosis of mediastinal lymphoma: a randomized trial.

We selected 95 patients with mediastinal adenopathy and no signs of goiter, myasthenia gravis or mediastinal involvement by other disease. All patients underwent, for screening purposes, transthoracic fine needle aspiration biopsy based on chest x-ray and CT findings. Patients were then subdivided into 4 groups. One group of 22 patients with prevalent anterior mass localization underwent anterior mediastinotomy. One group of 19 patients with prevalent middle mediastinal mass localization underwent cervical mediastinoscopy. Two other groups of 27 patients each with both anterior and middle mediastinum localization randomly underwent anterior mediastinotomy or mediastinoscopy. Fifty-one Hodgkin's and 44 non-Hodgkin's lymphomas were diagnosed in total. In 11 cases (11.57%), median sternotomy (2) or thoracotomy (9) were necessary for establishing the final diagnosis. The overall diagnostic accuracy was 80.43% for cervical mediastinoscopy and 95.91% for anterior mediastinotomy. The statistical analysis performed on all patients showed a significant difference (chi 2 = 5.56, P less than 0.025, df = 1) between the two procedures.     

Easier node dissection after chemoradiotherapy for lung cancer with collagen insertion at mediastinoscopy

Objective: Induction chemoradiotherapy followed by anatomical resection is a current therapeutic strategy for non-small-cell lung cancer with mediastinal node involvement. Dense peritracheal fibrosis and sclerosis after chemoradiotherapy cause difficult mediastinal node dissection. We evaluated a novel technique to make the mediastinal node dissection easier after induction therapy. Methods: At the end of mediastinoscopic node biopsy for staging of lung cancer, cotton-type collagen was inserted anterior and lateral to the trachea in patients with pathologically confirmed mediastinal node involve-ment (n=45). The induction therapy consisted of concurrent use of platinum-based chemotherapy and hyperfractionated radiotherapy. After the chemoradiotherapy all patients underwent a pulmonary resection with complete mediastinal node dissection 7–12 weeks after the collagen insertion. Surgical findings of the mediastinum and the time for node dissection were compared with those without collagen insertion at mediastinoscopy after chemoradiotherapy (n=5). Results: All five patients without collagen insertion showed sclerotic and fibrotic change of mediastinal nodes with severe adhesion to the trachea. In 42 of 45 patients with collagen insertion (93.3%) the collagen remained unabsorbed and separated the mediastinal nodes from the trachea. Mediastinal node dissection was easily accomplished by removing mediastinal tissues lateral and anterior to the collagen. The rate of mediastinal node separation was significantly higher with collagen insertion than without (p< 0.0001). The times for node dissection in patients with and without collagen insertion showed no significant difference. Conclusion: Cotton-type collagen insertion at staging mediastinoscopy for lung cancer separates the mediastinal nodes from the trachea and makes the node dissection easier after induction chemoradiotherapy.     

Psychosocial indicators and distress in immigrants living in Italian reception centres

Despite the high rate of migration to Italy, there are still no comprehensive studies of psychosocial distress in the different groups of immigrants. The objective of the present study was to investigate the psychosocial status of immigrants living in Bologna (Italy). We conducted a cross‐sectional survey of 396 immigrants (313 males and 83 females) from Africa, Asia and eastern Europe (Senegalese, Moroccans, Tunisians, Pakistanis, Kosovars and Roma) using questionnaires administered by trained anthropologists. Except for Tunisians, the psychological distress and discomfort of the immigrant groups are low, and the perception of their quality of life and well‐being is good. In the groups that have spent more time in Italy, the percentage of subjects wishing to return to their native country is generally higher. Immigrants living in Bologna exhibit a good psychosocial state and seem to have positively interacted with their new environment. Copyright © 2008 John Wiley & Sons, Ltd.     

Computed tomographic image comparison between mediastinal and lung windows provides possible prognostic information in patients with small peripheral lung adenocarcinoma

OBJECTIVES: The purpose of this study was to determine whether the ratio of the area of the mediastinal computed tomographic image to that of the lung computed tomographic image can be a prognostic factor of small peripheral lung adenocarcinoma. METHODS: We studied the computed tomographic images of 143 patients with primary peripheral lung adenocarcinoma of 30 mm or less in maximum diameter. Two groups were categorized according to the tumor's ratio of the area of the mediastinal computed tomographic image to that of the lung computed tomographic image (tumor's area in the mediastinal computed tomographic image/tumor's area in lung computed tomographic image x 100%), both faint density-type (<50%) and solid-type images (>/=50%). Clinical factors and prognoses of the 2 groups were analyzed. RESULTS: There were 58 patients with the solid-type tumor image and 85 patients with the faint density-type tumor image. The number of patients with tumor size of less than 20 mm in the faint density-type tumor group (n = 30) was significantly higher than that in the solid-type tumor group (n = 8, P =.008). The 5-year survival of patients with faint density-type tumors was 74.1%, whereas that in patients with solid-type tumors was 54.2% (P =.013). Furthermore, the survival curve of patients with the solid-type computed tomographic image combined with ground-glass opacity was similar to that of patients with the faint density-type image. Multivariate analysis revealed the prognostic influence of the ratio of the area of the mediastinal computed tomographic image to that of the lung computed tomographic image on survival (P =.029, relative risk = 0.48) and showed to be of second highest influence after the N factor. CONCLUSIONS: It is suggested that the ratio of the area of the mediastinal computed tomographic image to that of the lung computed tomographic image can be a prognostic factor in patients with small peripheral lung adenocarcinoma.     

Video-assisted mediastinal lymph node dissection assessed in an experimental setting

Background: Feasibility, completeness, and morbidity of videoscopic-assisted mediastinal lymph node dissection (VATS MLND) were compared to the standard surgical technique in an experimental study. Methods: Right upper MLND—together with upper lobectomy in half of the cases—was performed in ten large white pigs. Six animals were operated using VATS (group 1), four using conventional open techniques (group 2). After 1 week, the animals were sacrificed and the mediastinum was assessed for remaining lymph nodes. Results: All animals survived without intra- or post-operative complications. There was no significant difference in the operation time between the two groups (3.2±0.8 vs 3.2±0.2 h). The number of mediastinal lymph nodes harvested was 9.5±2.7 in group 1 and 11.5±0.5 in group 2 (n.s.). The post-mortem assessment of the mediastinum showed in two animals of group 1 and in two animals of group 2 that one lymph node was left behind. In addition, in one animal of group 1 four small retrotracheal lymph nodes were found. Conclusions: VATS MLND can be accomplished without morbidity and is as radical as that achieved with conventional surgery in the paratracheal and peribronchial areas in this experimental setting. However, retrotracheal lymph node dissection might not be as complete as achieved by conventional surgery.     

FDG/PET and spiral CT image fusion for medistinal lymph node assessment of non-small cell lung cancer patients

BACKGROUND: To assess the potential usefulness of 18F-FDG/PET and spiral-CT images concurrent assessment and coregistration in staging mediastinal lymph node involvement in patients with non small cell lung cancer. METHODS: 28 patients waiting to undergo surgical treatment underwent spiral-CT and PET examinations on the same day. The results of the two studies were interpreted separately, together (CT&PET) and following their fusion in a single image (CT+PET). Results of spiral-CT, PET, CT&PET and CT+PET were assessed with respect to the histological diagnosis. RESULTS: A correct assessment of mediastinal lymph nodes was achieved by spiral-CT in 21 of the 28 patients, in 22 of the 28 patients by PET, in 24 patients by CT&PET and in 25 patients by CT+PET. CONCLUSIONS: CT+PET is more accurate than spiral-CT and PET alone in staging mediastinal lymph node involvement in lung cancer patients, with possible implications for their prognosis and therapy.     

Prediction values for the ventilatory capacity in male West Pakistani workers in the United Kingdom

The ventilatory functions (forced vital capacity, forced expiratory volume in one second, and peak expiratory flow rate) of West Pakistani immigrants working near Manchester were measured. There were 198 `normal' healthy adult workers aged 25 to 60 years and 129 workers aged 16 to 24 years. The subjects were considered `normal' if they did not admit to persistent cough and phlegm. The regression equations on age and height for the two groups are presented together with the corresponding nomograms for the adult group.     

非小细胞肺癌淋巴结清扫方式临床研究

目的 比较非小细胞肺癌不同纵隔淋巴结清扫方式间的差异,为规范化开展肺癌淋巴结清扫临床研究提供依据.方法 在202例Ⅰa-Ⅲa期肺癌中进行前瞻性临床对照试验,比较常规清扫(RMLD)和全纵隔骨骼化清扫(SCLD)两种术式,分析手术经过和术后病理分期情况.结果 RMLD 107例,SCLD 95例.两组术前一般情况、临床分期及肺切除方式无明显差异,SCLD组平均扫除淋巴结组数显著高于RMLD组(8.9组对6.2组,P＜0.001),术后总体并发症(14.7%对14.0%,P=0.884)和病死率(2.1%对1.9%,P=0.904)无差异,但SCLD组分别有3例(3.2%)右侧乳糜胸和左侧喉返神经损伤发生.术后病理证实两组组织学类型及分期无明显差异,RNLD和SCLD组pN2分别占27.1%和24.2%(P=0.888),跳跃性纵隔转移率(RMLD 9.3%对SCLD 7.4%,P=0.613)以及纵隔多组转移率(RMLD 15.0%对SCLD 16.8%,P=0.714)亦无明显差异.分析纵隔各组淋巴结转移率发现上叶肺癌下纵隔转移率＜5%,而中、下叶肺癌上、下纵隔转移率均＞10%;cT1病例以及低度恶性肿瘤无一发生纵隔转移.结论 对非小细胞肺癌行常规纵隔清扫可达到与全纵隔骨骼化清扫同样的分期效果,后者手术风险并不高于常规清扫,但应避免右侧乳糜胸和左侧喉返神经损伤的发生;上叶肺癌仅需扫除上纵隔淋巴结而无需常规清扫下纵隔;早早期肺癌以及低度恶性肿瘤没有必要进行常规纵隔清扫.     

Classification for predicting mediastinal lymph node metastases in patients with T1 or T2 lung cancer

The aim of this study is to classify patients into risk groups for mediastinal lymph node metastases. Three hundred and thirty-seven patients underwent lung resection for lung cancer. The nodal status was pN0 in 181 patients, pN1 in 62 and pN2 in 94. The presence of the involvement of one mediastinal compartment (superior or inferior) or two mediastinal compartments (superior and inferior) was considered to be the main end point. One mediastinal compartment was involved in 65 patients and two mediastinal compartments in 29 patients. Two variables (visceral pleural invasion and the primary tumor location) were retained in the model. The regression tree analysis categorized patients into 3 risk groups for the involvement of two mediastinal compartments. The low-risk group included 118 patients with a tumor located in the left side and no visceral pleural invasion. The intermediate-risk group included 160 patients with a tumor located in the right side and no visceral pleural invasion. The high-risk group included 59 patients with visceral pleural invasion and a tumor located in the right side or left lower lobe. A practical, easy-to-use risk grouping system is proposed to aid the decision making and to simplify mediastinal lymphadenectomy procedure.     

Cavernous hemangioma of the superior mediastinum; report of a case

A 44-year-old female was admitted with an abnormal left mediastinal shadow on chest roentgenography. Computed tomography (CT) revealed a mass lesion in the left superior mediastinum, which was not enhanced with contrast medium. Magnetic resonance imaging demonstrated equal signal intensity to that of the muscle on T1 weighted images, and higher signal intensity on T2 weighted images. As a cystic mediastinal tumor was suspected preoperatively, thoracoscopic excision was performed. The tumor was diagnosed as a cavernous hemangioma by pathology. A preoperative diagnosis is difficult because of a variable feature of image study. When the diagnosis of the cystic tumor of mediastinum is made, the diagnosis of mediastinal hemangioma should be kept in mind.     

Coexistence of sarcoidosis and thymic carcinoid

We report a case of coexistence of sarcoidosis and thymic carcinoid. A 57-year-old man was pointed out the anterior mediastinal tumor when his generator of pacemaker was exchanged. The tumor was diagnosed as atypical carcinoid by percutaneous needle biopsy. Chest computed tomography (CT) revealed the mediastinal and right hilar lymphadenopathy. Preoperative transbronchial aspiration cytology revealed no malignancy and extirpation of the anterior mediastinal tumor was carried out together with left diagraphmatic nerve and pericardium. The histopathological examination of the pretracheal lymph node was sarcoidosis. Postoperative radiation was performed because the thymic carcinoid invaded the pericardium. The right hilar lymph node was enlarged after the radiation. Five months later, follow-up chest CT showed reduction of the right lymph node. He has been alive without recurrence of the thymic carcinoid for 3 years. Simultaneous occurrence of sarcoidosis and thymic carcinoid is extremely rare. Assessment of mediastinal lymph node is difficult either preoperatively and postoperatively. Histological confirmation of the lymph node and careful follow-up are necessary.     

直径≤3cm的周围型非小细胞肺癌纵隔淋巴结转移规律的初步研究

目的探讨直径≤3cm的周围型非小细胞肺癌(non-small cell lung cancer,NSCLC)纵隔淋巴结转移的情况,分析早期周围型NSCLC纵隔淋巴结转移的规律。方法 2000年1月1日～2008年12月31日治疗直径≤3cm的周围型NSCLC161例,男89例,女72例,年龄(63.4±10.7)岁,行肺叶切除或肺局限性切除加系统性纵隔淋巴结清扫术,分析其临床特征、病理特点及纵隔淋巴结转移规律。结果全组手术顺利,无死亡及严重并发症发生。肺叶切除153例,肺楔形切除7例,肺段切除1例。全组共清扫淋巴结2456枚,平均每例4.5±1.6组、13.1±7.3枚。术后病理:腺癌99例,鳞癌30例,肺泡细胞癌19例,其他类型肺癌13例。术后TNM分期:ⅠA期50例,ⅠB期62例,ⅡA期6例,ⅡB期10例,ⅢA期33例。N1组淋巴结转移率为23.6%(38/161),N2组转移率为20.5%(33/161),其中隆突下淋巴结转移率为8.1%(13/161),跳跃式纵隔转移率为6.8%(11/161),全组未发现下纵隔淋巴结转移。肺泡细胞癌及直径≤2cm的鳞癌、直径≤1cm的腺癌均无pN2转移。上肺癌发生pN2转移时上纵隔100%(19/19)受累,其中21.1%(4/19)同时伴有隆突下淋巴结转移;下肺癌则除主要转移至隆突下外(64.3%,9/14),还常直接单独转移至上纵隔(35.7%,5/14)。转移的纵隔淋巴结左肺癌主要分布在第5、6、7组,右肺癌主要分布在第3、4、7组。结论对于直径≤3cm的周围型NSCLC,肿瘤直径越大,其纵隔淋巴结转移率越高,肺泡细胞癌、直径≤2cm的鳞癌和≤1cm的腺癌其纵隔淋巴结转移率相对较低;上肺癌主要转移在上纵隔,下肺癌则隆突下及上纵隔均可转移;第5、6、7组淋巴结是左肺癌主要转移的位置,第3、4、7组是右肺癌主要转移的位置,术中应重点清扫。     

Early recognition of surgically correctable causes of excessive mediastinal bleeding after coronary artery bypass graft surgery

In an attempt to establish criteria to enable recognition of patients with surgically correctable causes of excessive mediastinal bleeding, 250 patients undergoing coronary artery bypass graft surgery were reviewed. Ten (4 percent) required reexploration for excessive postoperative mediastinal bleeding and were compared with 95 consecutive control patients. There were no statistically significant differences in preoperative coagulation studies, use of aspirin or warfarin, number of vessels bypassed or bypass time. Mean mediastinal blood loss was statistically greater (p <0.001) in the reexploration group for the first 8 hours of the postoperative period than in the control group. Mean heterologous blood transfusion was 8.4 units in the reexploration group compared with 1.3 units in the control group.Based on analysis of the differences in mediastinal bleeding rates in the control and reexploration groups, we conclude that after coronary artery bypass graft surgery postoperative mediastinal bleeding of greater than 300 ml in the 1st hour, greater than 250 ml in the 2nd hour, and greater than 150 ml/hour thereafter suggests the presence of a surgically correctable lesion.     

Mediastinal infection following open heart surgery

31 cases of mediastinal infection occurred in 7164 patients who had undergone open heart surgery under CPB were reviewed in the period of 1981-1989. The over-all incidence was 0.43%. Analysis of the clinical material showed that mediastinal infection was mostly associated with the following predisposing factors: (1) prolonged CPB time; (2) rethoracotomy; (3) open cardiac massage; (4) tracheostomy; (5) combined severe circulatory or/and respiratory complications. 28 patients were treated by mediastinal debridement and 27 of them were irrigated with 0.5% betadine or/and antibiotic solutions. Debridement was done a second time in 5 patients with smooth recovery. There were 15 deaths (48.4%), of which 4 were caused by rupture of cardiac or aortic incisions, 5 by multisystemic complications and 6 by severe infection. The mortality was significantly higher in the cases with combined circulatory or/and respiratory complications (72.2%) than in the cases of simple mediastinal infection (15.4%).