Lung Lesions (Newborn - CPAM etc)

Pediatric Surgery
Dr. Steven Rothenberg discusses Newborn Lung Lesions with Dr Todd Ponsky.
Edited by Ian C. Glenn, MD & Nicholas E. Bruns, MD

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Prenatal evaluation

  • Patients with prenatal diagnosis of cystic lung lesions are referred for prenatal evaluation and counseling.
  • Serial prenatal US is the best way to monitor development of prenatal lung lesions. They are performed every few weeks.
  • Fetal MRI is of little benefit for cystic lung lesions as they do not typically alter the management and provide little additional information over the ultrasound. Thus, fetal MRI is not typically recommended.
  • Fetal imaging features
    • Size, or change in size, of cystic lung lesions
    • Compression of normal lung and mediastinal shift
    • Fetal hydrops
    • There is regression in 6-40% of lesions, including complete resolution.

 

Fetal intervention

  • Fetal intervention, as a whole, is extremely rare.
  • Children’s Hospital of Philadelphia, who has the largest series, only performs open fetal surgery once every few years.
  • Fetal thoracentesis has been used to decompress the cysts or a thoraco-amniotic shunt may be placed.
  • The primary indication is hydrop fetalis.

Steroids

  • Large cysts with mediastinal shift are a common indication for prenatal steroid administration.
  • If early deliver is anticipated (as opposed to a routine, spontaneous vaginal delivery), steroids may also be indicated for lung maturation.

Cyst volume ratio (CVR)

  • Measured at some centers to quantify the cyst volume:head ratio. If this value is greater than 2, this has a very poor prognosis and these cases are more prone to requiring fetal intervention.

Spectrum of Congenital Pulmonary Adenomatoid Malformation (CPAM)

  • CPAM truly is a spectrum and the nomenclature likely will change again.
  • The simplest lesions are bronchogenic cysts, which may arise from the trachea or bronchus. They typically have a common wall and may be in the pulmonary parenchyma.
  • Pulmonary sequestration are typically supplied by a systemic artery, commonly directly from the aorta.
    • Intralobar – Located within the pulmonary parenchyma and shares a common pleura with the involved lobe.
    • Extralobar – Distinct from the pulmonary parenchyma and typically has its own, independent pleural lining.

CPAM or cystic lung lesions

  • Classified by size (type 1 – macro, type 2 – medium, type 3 – solid, worse prognosis, type 4 – tiny)
  • These are all considered a spectrum. However, if they are supplied by a systemic vessel they are considered pulmonary sequestration.

Routine neonatal care

  • All patients should get CXR to rule out large cystic component.
  • If CXR only shows mild disease (or no disease), mother and baby are routinely discharged from the hospital.
  • Pt then gets a CT at 4-6 weeks of life. This is important because even if the fetal US was showing regression of the lesion and CXR was negative, this needs to be definitively proven on CT.  Of note, intervention would not be undertaken until at least 4-6 weeks of age.
  • MRI is not routinely used for diagnosis or surgical planning.
  • US is also not a good modality for the postnatal period.
  • 20-40% of CPAM spectrum lesions will develop a serious infection. There is also a risk of malignancy which may be greater than 1%.

Decision to operate

  • Dr. Rothenberg and Dr. Alan Flake (from CHOP) tend to operate early, typically by 3 months of age. If patients have respiratory distress, they may require earlier surgery.
    • Operating early helps to minimize the risk of infection and/or inflammation, both of which may be subclinical until the time of surgery.
    • Surgery is technically easier in younger/smaller patients (e.g. smaller vessels).
    • The remaining lung following resection has better opportunity to undergo compensatory growth following surgery.

Too small for thoracoscopic surgery?

  • In actuality, intrathoracic space does not tend to be a problem, even in very small/young patients. Additionally, the surgeries are easier due to smaller vessels.
  • They key is proper port placement and setup for the case.

Preoperative preparation

  • Many patients do not require pre-op preparation.
  • Neonates are still approached thoracoscopically.
  • Type/cross and CBC are the only required lab work.
  • Patients arrive the morning of surgery

Anesthesia

  • Single-lung ventilation is preferable. This is accomplished via main stem intubation. Most patients, particularly those who are breathing comfortably on room air prior to surgery, will tolerate single-lung ventilation in the OR.
  • Bronchial blockers are not recommended to aid in mainstem bronchus intubation.
  • If single-lung ventilation is not tolerated, then a small amount of CO2 insufflation in the hemithorax is used to collapse the lung (creating a mild tension pneumothorax).
  • Pitfalls
    • Over-ventilation
    • High peak ventilator pressures (respiratory rate should be increased, not pressure)
  • Oxygen desaturation and hypercarbia should be expected for a few minutes following initiation of single-lung ventilation and/or insufflation of the hemithorax. This will resolve.

Patient positioning

  • Lateral decubitus position. Move the patient to the edge/side of the table. Surgeon and assistant face the anterior chest.
  • Towel rolls or beanbag are used to aid in positioning

Trocar placement

  • Depends on which lobe is being resected
  • Scope port should be positioned over where the surgeon anticipates the major fissure is located. It should be in the mid-axillary line, anterior to the tip of the scapula. This allows the surgeon to work "front to back”.
  • For a lower lobe this would be in the 5thor 6th intercostal space.
  • Working ports are in the anterior axillary line.
  • For the left chest, the left-hand port is under the camera port (5th or 6th intercostal space) and the right-hand port is just above the diaphragm. The reverse of this setup is used for the right chest.
  • A 4th port is used almost never.

Instrument selection

  • Low-profile, 3-mm reusable ports with valves
  • A 4-mm 30 degree "short” scope (20 cm length)
  • 3-mm instruments are used (18-20 cm length)
  • A 5-mm port may be used in the lower port position for use of a clip applier, stapler, vessel sealer, etc.

Vascular control

  • Vessel sealing (with the JustRight 3mm vessel sealer): Make 2 separate seals on the vessel as far apart as possible (at least 4-5 mm). Then cut between the two seals.
  • Dissect vessels in a fashion that creates enough space to provide for adequate sealing. When the vessel is cut, it should be only partially cut (just enough to see the lumen) such that if there is bleeding it is easier to control.
  • You only lose control once you’ve completely divided the vessel.”
  • Vessel clips are not used routinely as they can fall off or be knocked off.
  • A device which seals and cuts at the same time should be avoided, as bleeding can be very difficult to control. If the JustRight device is not available, a LigaSure, which allows for sealing without cutting, should be implemented.

Left lower lobe technique

  • Right lateral decubitus position
  • Right main stem intubation
  • Camera port in 6th intercostal space in the midaxillary line
  • Left-hand port in 5th or 6thintercostal space in the anterior axillary line
  • Right-hand port in 8th or 9thinterspace just above the diaphragm
  • Operative Steps
    • Take down inferior pulmonary ligament to the level of the inferior pulmonary vein. This provides opportunity to test the energy source (in a relatively avascular structure). Additionally, if there were a systemic vessel supplying a pulmonary sequestration, it would be located here.
    • The inferior pulmonary vein is exposed such that in the even of bleeding, it may be easily ligated.
    • Attention is directed to the major fissure. The ease of the operation is affected by the level of development of the major fissure.
    • If the major fissure is incompletely developed, the development is "completed” with the vessel sealer. This is performed in a controlled, methodical fashion akin to finger fracture in open liver lobectomy surgery. Moving in an anterior-to-posterior fashion the major fissure is developed until the pulmonary artery is exposed.
    • Once the trunk the pulmonary artery is identified, any dissection anterior to that structure will be "safe”. The pulmonary artery is thus unroofed.
    • The left pulmonary artery typically has a main trunk which divides into 4 branches.
    • Superior segmental branch is dissected, sealed, and divided. This provides more access to the main trunk, which supplies the basal segments.
    • The bronchus is posterior to the artery and can be used to guide dissection.
    • If there is adequate length, the basal trunk may be divided (with vessel sealer or 5-mm stapler). Otherwise, the basal segment branches may be individually exposed and divided. If the stapler is used, there should be enough proximal vessel exposed to apply a clamp in the event of stapler malfunction.
    • The superior segmental bronchus is isolated and divided with clips or a 5-mm stapler. Of note, posterior to the bronchus is the inferior pulmonary vein. In patients over 10 kg, a 12-mm stapler will likely be required to divide the bronchus.
    • The inferior pulmonary vein is exposed after the bronchus has been divided. The bifurcation should be identified. The inferior branch is typically smaller and divided first, with the vessel sealer. The base of the trunk is held with an atraumatic grasper (providing proximal control) and a stapler is then used to divide the trunk.

Do not divide the trunk near the pericardium. If the device fails, the vessel will retract into the pericardium, and the patient will have massive hemorrhage. Enough space needs to be present on the proximal trunk to obtain proximal control.

Right lower lobe is the exact opposite as the left lower lobe ("just switch hands and flip sides”)

  • Pearl: As the pulmonary artery to the lower lobe is isolated, the branches to the middle lobe will be immediately superior to that. Do not be confused by which artery is which.

Left upper lobe

  • All of the ports are moved up one rib space compared with operating on the left lower lobe. Thus, the camera should be inserted in the 5th intercostal space, The left-hand port in the 4thor 5th intercostal space and the right-hand port in the 7thor 8th space. The same principles apply to the right upper lobe.
  • Operative Steps
    • The lung is retracted with the left hand grasping the apex of the lung and retracting inferiorly to expose the pulmonary artery.
    • The scope should be angled appropriately to provide a good view of the main pulmonary artery.
    • The artery supplying the apex and anterior segment is identified. Dissection is carried out to the level of bifurcation prior to sealing and division of the vessel.
    • Lung is retracted posteriorly to expose the superior pulmonary vein. These branches are sealed and divided as they enter the upper lobe. Care should again be taken to do this distal from the pericardium.
    • Work is continued inferiorly to find the pulmonary vein to the lingula, which is divided.
    • Attention is turned to the fissure. If it is incomplete, the fissure is completed (as previously discussed).
    • The lingular artery is next encountered, and divided.
    • The left upper lobe bronchus is identified and divided, either proximally or distally, at the first bifurcation, in larger children.

Right middle lobe

  • Operative Steps
    • Completion of the minor fissure is carried out toward the major fissure. Additionally, locating the middle pulmonary vein can help to elucidate the anatomy.
    • The major fissure may also require completion.
    • The pulmonary artery will be encountered at the posterior aspect of the middle lobe and bifurcates into upper and lower branches, which are divided.
    • The bronchus will be identified next.

Lobectomy technical pearls

  • Be methodical
  • Form a good mental image of the anatomy
  • Minimize "flipping the lung back-and-forth”
  • In a lung with large cysts (and thus limited space), use the sealing device to pop and decompress the cysts.

Extralobar sequestration

  • There may be multiple vessels (as many as 6) and they can have significant variation in size.
  • The vessel is exposed and clipped.
  • There should be enough length on the vessel to apply clips proximally and distally, and to allow for equipment failures.
  • Chest tube is not routinely placed.
  • It is not a good idea to use a vessel sealer and clips on the same vessel.

Alternatives to resection of pulmonary sequestration

  • Concern for infection risk
  • Unknown malignancy risk
  • Embolization is performed in some parts of the world, but there is comparable or less morbidity in performing thoracoscopic resection.

Segmental resection as alternative to lobectomy

  • There is a role for segmental resection, particularly in patients who would otherwise require a pneumonectomy.
  • Lingula and superior segments of the lower lobes are the easiest areas to perform segmental resection.
  • Overall, segmentectomy is not widely recommended and is still under evaluation.

Lobectomy post-operative course

  • Chest tube is always placed and left in at least overnight.
  • If there is no air leak or significant drainage, the chest tube is removed the morning of post-operative day #1 and a chest x-ray is performed 2 hours after removal.
  • Discharge on POD#1 if the family lives locally.
  • Average length of stay is 2.5 days.

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