Young children cannot articulate their sensations, so parents should be asked to give a detailed history. Particular attention should be paid to symptoms of irritability, pain, fevers, fatigue, shortness of breath, stridor, anorexia, exercise intolerance, nausea, vomiting, and bowel movement changes.

Duplication cysts of the mediastinum often become infected and induce fever and cough. Fever and diarrhea can be symptoms of neuroblastoma and often prompt an infectious work-up. Weight loss despite adequate feeding can be an insidious sign of widespread pathology.

Compression of cardiovascular or respiratory structures is a very serious symptom of a mediastinal mass. Compression of the superior vena cava may result in superior vena cava syndrome with significant venous distention of veins superior to the heart. The most common symptoms are dyspnea and fullness of the face. Other symptoms include cough, arm swelling, dysphagia, chest pain, stridor, headache, vision changes, and hoarseness [4].

Patients may also present with heart failure due to compression of one of the great vessels of the heart. Rarely patients will present with paraneoplastic syndromes like opsoclonus-myoclonus syndrome from a neuroblastoma.

Routine labs including complete blood count, electrolytes, creatinine, liver function tests, and coagulation studies are standard laboratory work-up.

Lactate dehydrogenase may be elevated in lymphoma. Alpha-fetoprotein and beta-human chorionic gonadotropin may be elevated in nonseminomatous germ cell tumor s. Neuroblastoma may have elevated catecholamine breakdown products, specifically urinary vanillylmandelic acid (VMA) and homovanillic acid (HVA).

A chest x-ray is obtained as a first diagnostic test. An MRI may be helpful to diagnose some lesions, particularly neurogenic tumors. A CT scan is diagnostic for many lesions, and its delineation of structures and anatomic planes is superior for operative planning of lesion resection (Fig. 18.1).

When a pediatric mediastinal mass is discovered, a treatment plan should be put into place to diagnose the lesion and treat appropriately. Prenatal diagnosis of a suspicious mediastinal mass should prompt a plan for resection within the first year of life before symptoms develop [6]. Mediastinal masses diagnosed after birth should be treated, especially if symptomatic. Surgery is the primary treatment for all mediastinal masses except for lymphoma, which is treated with chemotherapy, and therefore tissue diagnosis is important to determine appropriate treatment [7]. Some masses may be unresectable at time of diagnosis due to invasion of non-resectable structures and should be biopsied first if possible to make a diagnosis to direct neoadjuvant chemotherapy or radiation.

Large, symptomatic masses should be biopsied under local anesthesia due to the significant risk of cardiovascular collapse under general anesthesia and positive pressure ventilation. Duplication cysts warrant excision as they are often symptomatic from mass effect on surrounding structures, can become infected, and have a potential for malignant transformation [8].

Evaluation of the anatomy is critical prior to surgery. Cross-sectional imaging will allow you to assess the extent of disease and determine resectability. Unresectable tumors will invade into the great vessels, pericardium, lung, or spinal cord. Foregut duplication cysts will share a wall with its tissue of origin.

It is important to have a clear anesthetic plan when preparing for surgery. Having an anesthesiologist experienced with pediatrics and minimally invasive thoracic surgery is recommended. Acceptable perioperative antibiotics include appropriately dosed cefazolin, ampicillin-sulbactam, vancomycin, or clindamycin [18].

General anesthesia is poorly tolerated in children with large mediastinal masses because their airways are more collapsible than those of adults. These factors, combined with decreased muscle tone and the supine position, increase the intrathoracic pressure and can occlude airways or prevent return of blood flow to the heart [19].

It is recommended to have a discussion with the anesthesiologist about the anesthetic plan prior to entering the operating room. Single lung ventilation may be used but is not always necessary. A double lumen tube can be used in children that are 8 years old or large enough for a 6.0 cuffed endotracheal tube, but smaller patients may require either single bronchus intubation or the use of a bronchial blocker. It is recommended that either of these techniques be done under direct visualization and placement confirmed with fiber optic bronchoscope. Insufflation of the thorax with 5–8 mmHg of CO2 is usually well tolerated and is often sufficient to deflate the lung. If insufflation is used, the anesthesiologist should be vigilant about monitoring for tension pneumothorax physiology and be prepared to alert the surgical team to desufflate immediately [20].

The room should be set up to easily transfer the patient to the operating table. Anesthesia is located at the head of the bed. The surgeon stands on the side of the patient opposite the pathology. The assistant stands above or opposite the surgeon. The surgical technologist is positioned near the foot of the bed on the side of the surgeon. It is ideal to have multiple video displays in line with the pathology facing the surgeon and the assistant.

Correct positioning of the patient is critical to the success of the operation. Gravity should be used to optimize exposure. The patient is positioned laterally with the lesion being as perpendicular to gravity as possible. Anterior masses are best approached with the patient in lateral decubitus and rolling the patient to be partially supine. Likewise, exposure to posterior masses benefits from the patient being tilted toward the prone position. Inferior masses benefit from Trendelenburg positioning, while superior masses benefit from reverse Trendelenburg. Towel or gel rolls are helpful in supporting smaller patients, while a beanbag should be considered for larger patients. Ensure that the arms are placed on arm boards and are not under stretch. The break in the surgical bed should be placed at the space between the inferior border of the lateral rib cage and the iliac crest to facilitate opening the rib spaces. A towel roll beneath the small child or neonate may be an adequate alternative to a break in the bed. When the patient is positioned, ensure that there is adequate clearance to manipulate instruments from the desired trocar positions.

Standard laparoscopic instruments of appropriate size are sufficient for resection or biopsy of most mediastinal masses. Devices such as monopolar cautery via hook or scissors, a sealing device, or ultrasonic energy device are helpful to work with and can be chosen based on surgeon preference. In smaller kids, 3-mm trocars, instruments, and cameras may be used. There is a 3-mm sealing device that is available and that is helpful in the neonatal population. If a stapling device will be used, it is possible to use a 5-mm stapler, but otherwise consider which 5-mm port may be upsized to a 12-mm port to allow this if necessary. The smaller children have small rib spaces, and posterior rib spaces may be too small to comfortably place a 12-mm trocar. Also consider how you will remove the surgical specimen. Removing the specimen through a 5-mm incision is sometimes possible when the trocar has been removed.

Steps for placing trocars will use the same technique for each type of procedure but location of trocars will vary based on location of the mass. Local anesthesia is injected at the site of trocar placement by first feeling the rib inferior to the location with the needle then moving superiorly and injecting the inter-rib space. A small incision is made and the thorax can be entered with an open technique using a curved clamp or with a Veress needle. Insufflation to a pressure of 5 mmHg is tolerated well and assists with lung deflation. If using a Veress needle, dilatable expandable trocars are deployed after insufflation otherwise a regular trocar is placed. Insertion of a 3- or 5-mm 30-degree scope to view the location of the surgical target will help guide subsequent trocar placement. Two additional 3- or 5-mm ports should be placed under direct vision in a position that will allow triangulation. Trocars should be placed at least the distance of a closed fist away from one another, one trocar on the right and left of the camera. When placed under direct visualization, trocars can be placed in the posterior axillary line as high as the scapula allows and as low as the ninth or tenth intercostal space. Additional ports can be placed as needed, or 3-mm instruments can be placed through a stab incision without use of a trocar.