Presentation on theme: "SURGICAL DISORDERS OF MEDIASTINUM AND DIAPHRAGM"— Presentation transcript:
1SURGICAL DISORDERS OF MEDIASTINUM AND DIAPHRAGM Sina Ercan MDProfessor of Thoracic Surgery
2Anatomy of the Mediastinum Mediastinum is the central space within the thoracic cavity bounded by:Sternum anteriorlyLungs and parietal pleura laterallyThe vertebral column posteriorlyThe thoracic inlet superiorlyThe diaphragm inferiorlyThoracic inlet is composed of 1. ribs, claviculas, suprasternal nodgeand T1 vertebrae. The mediastinal structures are seperated from the thoracic cavity by parietal pleura.
6Compartments of mediastinum Anterior mediastinum: the area posterior to the sternum and anterior to the heart and great vesselsThymus, substernal thyroidglands, parathyroid,lymph nodes,connective tissue
7Middle mediastinum: the area between the posterior border of the anterior mediastinum and a line placed along the posterior aspect of the trachea and the heartHeart, pericardium, aortic arc,brachiocephalic vessels, vena cava ,main pulmonary vessels, trachea,main bronchi, phrenic and upperparts of the vagus nerve,lymph nodes
8Posterior Mediastinum: The area between the posterior aspect of middle mediastinum and the vertebrae Esophagus, azygos and hemiazygos veins, thoracic duct, descending aorta, autonomic ganglia, symphathetic chain,lower portions of the vagus nerve,lymph nodes and connective tissueIt is important to know which tissues are present in different compartments of the mediastinum in order to differentiate the origin of a disorder.
9Mediastinal Pathologies Non neoplastic diseasesMediastinitisPneumomediastinumCongenital pathologiesCystsHerniasAcquired lesionsBenignMalignant
10Mediastinal Pathologic Lesions In adults 65% of the mediastinal lesions are anteriorIn children 52% of the mediastinal lesions are posterior40-50% of the mediastinal lesions are malignant in children compared to 25% malignancies in adults
11Anterior mediastinal disorders Thymic disordersThymoma, Thymic carcinomaThymic carcinoidThymolipomaThymic cystThymic hyperplasiaThyroid disordersIntrathoracic goiterGerm cell tumorsTeratomaSeminomaOthersLymphomaHodgkin’s diseaseNon-Hodgkin’sParathyroid adenomaMesenchymal tumorsThe origin of the most frequent lesions in adults are Thymic, Thyroid disorders and Teratomas but lymphomas should always be in the differential diagnosis.
12Thymoma Most common adult 10 mediastinal neoplasm Usually >40 y/o 40-70% have symptoms related to parathymic syndromesMyasthenia Gravis,HypogammaglobulinemiaPure red cell aplasiaNonthymic malignanciesUsually discovered incidentaly on plain chest radiography as rounded , well circumscribed anterior mediastinal enlargement.
13Thymomas represent neoplastic proliferation of thymic epithelial cells mixed with mature lymphocytes CT demonstrates a homogenious soft tissue massCT guided needle biopsy, mediastinoscopy, mediastinotomy or VATS for diagnosis
15Thymic Carcinoma: Thymic carcinoid: Thymolipoma: Malignant histologic featuresPulmonary, regional lymph node or pleural metastasis can be presentThymic carcinoid:a rare agressive neoplasm that originates from thymic neuroendocrine cellsThymolipoma:a rare benign tumor composed of mature adipose and thymic tissue
16CT image of a Thymolipoma (Exhibits fat and thymic soft tissue)
17Thymic cysts: May be congenital or acquired in association with inflammation or malignancy Thymic hyperplasia: May be a rebound phenomenon after lymphoma or germ cell tumor treatment or seen in MG
18Mediastinal Lymphoma 10-20% of all mediastinal neoplasms in adults May be 1o in anterior or middle mediastinum or part of systemic malignancy20-30% of patients are asymptomaticSymptoms of local invasion or systemic symptoms (fever, weight loss, pruritis)
19Hodgkin’s disease: Bimodal age peak (20-30 years; >50 years) Majority of patients have asymmetric, bilateral mediastinal LAP
20Non-Hodgkin’s Lymphoma: Usually in older patients Usually systemic upon presentation and spreads unpredictablyDiffuse Large B-cell LymphomaLymphoblastic Lymphoma
21Mediastinal Germ-Cell Tumors Teratomas:Account 60-70% of casesConsist of tissue that may derive from more than one of the germ cell layersMostly benign, radiologically spheric, lobulated, well circumscribed and may contain calcificationSeminomas:Affect men in 3rd and 4th decades40-50% of mediastinal malignant germ cell tumors
22Teratoma (well formed teeth within the mass is diagnostic)
25Benign mediastinal lymphadenopathy InfectiousTuberculosis: Usually unilateral and asymmetric, may have calcificationFungal infectionsHistoplasmosiscoccidioidomycosisNon infectiousSarcoidosis: Usually bilateral, symmetricSilicosis: nodal calsification with eggshell configuration
28CystsBronchogenic cyst: Originate from abnormal budding of ventral foregutCommonly in subcarinal and paratracheal regions 15% in pulmonary paranchymeLined by respiratory epithelium and may contain serous fluid, mucus, milk of calcium, blood or purulent materialRadiologic imaging a well cicumscribed spheric mediastinal mass with fluid density on CT
30Diaphragmatic hernias: Enterogenous cysts:Esophageal dublication and neurenteric cystsLocated in the middle or posterior mediastinumPericardial Cysts:In the cardiophrenic angles (R>L)Fibrous walls and contain clear fluidDiaphragmatic hernias:Hiatal herniaMorgagni herniaBochdalek herniaMorgagni hernia is seen as a right cardiophrenic angle mass. Bochdaleck hernia is located in the posterior mediastinum
32Vascular lesions: Constitute approximately 10% of the mediastinal masses May originate from the arterial or venous portions of the systemic or pulmonary circulationThey may mimic neoplasms on chest radiographs
37Symptoms and signs in mediastinal pathologies Benign ones usually asymptomaticChest pain (Traction of the mediastinal structures, bone erosion)CoughDyspnea (Compression of tracheobronchial tree, mediastinal shift)Dysphagia (Compression of esophagus)Hoarseness (Recurrent laryngeal paralysis)Horner syndrome (Compression of the stellate ganglion)Horner Syndrome: Myosis, pitosis, enophtalmia, unilateral anhydrosis
38Superior Vena Cava Syndrome Weakness/Myastenia Gravis SymptomsMental Confusion (Hypercalcemia due to parathyroid adenoma or carcinoma)Neurogenic symptoms (Neurogenic tumors)Diaphragmatic paralysis (Phrenic nerve paralysis)Pleural effusion/Chylothorax (Obstruction of thoracic duct)Arrhytmias (Cardiac compression or involvement of myocardium with tumor)Pericardial tamponade (Lymphoma)Gynecomastia (Germ cell tumors)
39Diagnostic Procedures Physical examination (Signs of Sup. V. Cava or Horner Syndrome)Plain Chest Radiography (PA and Left lateral)
42Non neoplastic Disorders of the Mediastinum PneumomediastinumPneumopericardiumAcute MediastinitisChronic Mediastinitis
43Pneumomediastinum Caused by alveolar overdistention and rupture Air moves through the bronchovascular sheath toward mediastinum. As the pressure rises in mediastinum, air moves to cervical, subcutaneous and retroperitoneal soft tissue places.
44Etiology of pneumomediastinum SpontaneousAcute asthma attackScuba divingMechanic ventilationVomitingTraumaSurgeryTracheostomyBronchoscopic proceduresRespiratory tract infectionsDental infections or proceduresAcute mediastinitisPneumoperitoneumEsophageal perforation
45Substernal chest pain is the most frequent symptom Crepitation; air dissecting under the skinDyspneaDysphagiaDysphoniaHypotension (hemodynamic changes)
46Physical examination reveals palpable subcutaneous emphysema in the neck On auscultation of the chest a clicking sound over the pericardium synchronous with the heartbeat (Hamman’s sign)
47Chest Radiograph: a thin radiolucent strip along the mediastinal fascial plane, left heart border CT
49Treatment: Supportive Supplemental oxygen Management of causes Surgery, chest tube insertion when hemodynamic deterioriation is present or when associated with mechanical ventilation
50Acute Mediastinitis A life threatening condition Etiology Esophageal or tracheobronchial perforationSternotomy for cardiac surgeryDirect extension of infection from lung, spine or pancreasDescending necrotizing mediastinitis (Oropharyngeal infections)Anthrax Mediastinitis
51Esophageal perforation Iatrogenic esophageal perforation is the most common cause of acute mediastinitisCan also be:Postemetic (Boerhaave’s syndrome)TraumaOperative injuryCancer erosionForeign body
55Treatment: Surgical debridement of the necrotic tissue Closure of the perforationDrainageBroad spectrum antibiotics with anaerobic coverageMortality rises when the treatment delay is more than 24 hours
56Poststernotomy mediastinitis: Prolonged preoperative hospitalization, reoperation or reexploration, presence of D. Mellitus, use of internel thoracic artery grafts are the risk factors.Staphlococcus epidermidis and aureus, various gram (-) organisms and candida and atypical mycobacteria are commonly isolatedInsidious presentation with low grade fever, leukocytosis, wound problemsSurgical debridement and prolonged proper antibiotic therapy is the treatment
57Antrax Mediastinitis: Caused by Bacillus anthracis (Gr + )Farm animals are the main reservoirInhaled antrax spores are transported to the mediastinal lymph nodes by alveolar macrophagesA hemorrhagic mediastinitis occursPenicillin and streptomycin is the treatment of choice
58Chronic Mediastinitis Granulomatous mediastinitisTbc, histoplasmosis, nocardia and other fungiDisease of mediastinal lymph nodesCoalescence of caseous mediastinal lymph nodes can result in a single large mass, encapsulation and mediastinal granulomaCompression of trachea, superior V. Cava or esophagus can occurRight paratracheal area is the most common site
59Excision is the treatment of choice (if possible) Specimens for culture and special stains for diagnosis at the time of operation
60Fibrosing Mediastinitis: Dense fibrosis surrounding trachea, hila of the lungs.Compression of the airway, pulmonary arteries or veins may occurEtiology:TuberculosisHistoplasmosis or other fungiSilicosisDrugs (Methisergide)Autoimmune disordersFamilial multifocal fibrosclerosis
61Symptoms are caused by the compression of vital organs Treatment is symptomaticMethisergide should be stopped for the relief of symptomsEND
62Diseases of the Diaphragm Diaphragma is a dome shaped musculotendinous structure that separates thoracic and abdominal cavitiesIt consists of two parts:Right hemidiaphragmLeft hemidiaphragmMiddle portion is made of the central tendon that doesn’t contract, it has two holes onThe caval openingThe esophageal hiatus
65The muscle fibers of the crural part originate from lomber vertebrae The muscle fibers of the costal part originate from the processus xiphoideus and 7-12 ribsThe costal part contraction lowers the diaphragm and increases the rib cageWhen the crural part contracts only the diaphragm moves downward
66Motor inervation comes from cervical motor neurons (C3-5) conducted via N. Frenicus Diaphragm is the major inspiratuar muscle responsible from 70% of normal breathing.
67Contraction of the diaphragm has the following effects that promote air movement into the lungs It decreases intrapleural pressureIt raises and inflates the rib cageIt expands the rib cage by generating positive intraabdominal pressure
68Diaphragmatic paralysis: Can be bilateral or involve only one side (unilateral)In this setting the accessory muscles of the respiration assume some or all the work of breathing
70Patients with bilateral diaphragmatic paralysis typically present with dyspnea. It is associated with tachypnea and rapid shallow breathingParadoxal motion of the anterior abdominal wall during inspiration can be detectedHypoxemia is common due to atelectasis and V/Q mismatch which worsens with sleepDisease progression is associated with progresive hypercapnia
71Chest radiograph reveals elevated hemidiaphragms, small lung volumes, atelectasis In pulmonary function test 50% decrease in VC in supine position is thypical (should be up to 10% in normal individuals). PI-max is loweredElectromyography may show either neuropathic or myopathic patternThe gold standart is the measurement of transdiaphragmatic pressure
72Unilateral diaphragmatic paralysis is more common Often discovered incidentally on a chest radiograph and diagnosis can be made only by radiology (fluoroscopic sniff test)Patients who do not have underlying lung disease are usually asymphtomaticIn fluoroscopic sniff test paradox elevation of the paralysed hemidiaphragm is positive >90% of the patients
73Diaphragmatic Fatique Can be seen in several conditions that effect motor neurons, neuromusculer junction or muscle cells
77Eventration of the diaphragm can be congenital or acquired Many patients are asymptomatic, especially when the eventration is localizedCan be seen incidentally on chest x ray and The diagnosis is confirmed by fluoroscopy or ultrasonography.In infants the management depends on the extent of the respiratory distress, often no need to treatmentIn infants surgical pilicatiomn can be performed
78Diaphragmatic Hernia Hiatal Hernias: Traumatic rupture Result when an abdominal structure usually the stomach extends through the diaphragmatic esophageal hiatus into the thorax. Manifests as a retrocardiac mass in the middle mediastinumTraumatic ruptureSeen in 1-4% of blunt chest or abdominal trauma usually on the left posterolateral region
80Congenital Hernias:These are due to the failure of the normal fusion of the diaphragmatic components during embryologic developmentMorgagni hernias: herniation of omentum and other abdominal contents into the thorax manifest as a right cardiophrenic angle massBochdaleks hernias: May protrude into the posterior mediastinumDiagnosis can be established in diaphragmatic hernias by gastrointestinal barium study or CT. Treatment is surgical in symptomatic cases.
83Diaphragmatic infections Subdiaphragmatic abscess: Can be seen due to perforation or abdominal surgery. Local pain, fever, tachicardia, leucocytosis are common. Ipsilateral hemidiaphragm is elevated on chest radiology. Pleural efusion, pulmonary infiltration or atelectasis can also be present. Surgical drainage with appropiate antibiotics is the treatmentParasitic infections: Amebiasis, trichinella spiralis
84Diaphragmatic neoplasms Metastatic: Breast, ovarian and gastric cancer metastasis are the most common type. Lung cancer and mesothelioma are also seenPrimary benign neoplasms:FibromaAngiofibromaneurofibroma,NeurilemmomaHemangioperistoma
85Primary malign neoplasms: FibrosarcomaMyosarcomaFibrangioendotheliomaSarcomaNeurofibrosarcomaHemangioendotheliomaHemangioperistomaLeiomyosarcomaMalign snoviomaThey are all mesenchimal tumors. Fibrosarcoma is the most common type