Fetoscopic Endoluminal Tracheal Occlusion (FETO)

Published: 2021-07-15

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Inside this episode

Kai, the Library's AI content creator, listened to this episode and mapped who's speaking, the chapters, key claims, and cases. Every item links to the exact moment in the recording.

AI-enriched

Who's speaking

Rob Gerardo — host
Dr. Fung Lim — guest

Chapters

0:00Introduction and Context — Host Rob Gerardo introduces the episode on fetal surgery for congenital diaphragmatic hernia and introduces Dr. Fung Lim from Cincinnati Children's Fetal Care Center.
1:18CDH Severity Classification and Imaging — Dr. Lim explains the difficulty of determining diaphragm defect size and describes the spectrum of CDH severity from mild to severe, with severe cases showing liver herniation and bilateral lung compression.
2:41FETO Procedure Technique — Description of the tracheal occlusion procedure timing, anesthesia approach, fetoscopic insertion technique, balloon placement in the trachea, and the mechanism by which tracheal occlusion promotes lung growth.
4:12Balloon Removal and Delivery — Explanation of balloon removal at 34 weeks gestation using either ultrasound-guided puncture or grasper retrieval, followed by monitoring and preference for vaginal delivery at term.
5:13Closing — Host concludes the episode and provides information about podcast platforms and future content.

Key claims

1:29It is difficult to determine with imaging exactly how large the hole in the diaphragm is in CDH — Dr. Fung Lim
1:40Ultrasound is usually the screening tool used to find congenital diaphragmatic hernia in the fetus — Rob Gerardo
1:48MRI provides higher resolution imaging than ultrasound for fetal CDH and can provide information about the pulmonary status of the fetus — Rob Gerardo
2:05In mild diaphragmatic hernia, the left lung starts to shrink in size — Dr. Fung Lim
2:11In moderate diaphragmatic hernia, the left lung gets smaller as the intestines and part of the liver push upwards — Dr. Fung Lim
2:24In the most severe CDH cases, the liver occupies a good portion of the chest, the left lung is very small, and even the right lung is shrinking — Dr. Fung Lim
2:35Fetuses with severe CDH are good candidates for FETO — Rob Gerardo
2:44The tracheal occlusion procedure is commonly performed at gestational age between 27 weeks and 29 weeks and 6 days — Dr. Fung Lim
2:58Local anesthetic with numbing medication is injected into the mother for the FETO procedure — Dr. Fung Lim
3:04An introducer is inserted into the amniotic space to allow placement of a fetoscope — Dr. Fung Lim
3:16The fetoscope is advanced carefully into the fetal trachea once the baby's mouth is located — Dr. Fung Lim
3:27The ideal position for the fetoscope is in the main trachea below the vocal cords but above the carina before the trachea splits into the two main bronchi — Dr. Fung Lim
3:38A balloon is inserted into the airway, inflated to completely occlude the trachea, then detached and left in place — Dr. Fung Lim
3:48Fetal lung tissue constantly creates fluid that normally escapes through the trachea — Rob Gerardo
3:52When the trachea is occluded, fluid continues to build up and pressure builds in the trachea, which helps the lungs develop — Rob Gerardo
4:12The balloon is left in place for a few weeks to accelerate lung growth — Dr. Fung Lim
4:18Balloon removal is typically attempted at about 34 weeks gestation — Rob Gerardo
4:26If the baby is in proper position, the balloon can be punctured under ultrasound guidance — Dr. Fung Lim
4:33The deflated balloon is pushed out of the baby's trachea by lung fluids and poses no risk to the baby's health — Dr. Fung Lim
4:40If the baby's position doesn't allow for needle puncture, a grasper is used to hold the balloon while a needle punctures it, then the deflated balloon is removed using the grasper — Dr. Fung Lim
4:56The mother and fetus are monitored carefully for the remainder of the pregnancy after balloon removal — Dr. Fung Lim
5:02Ideally, the baby is delivered vaginally at term with C-section reserved for the usual obstetrical reasons — Dr. Fung Lim

This episode was analyzed and enriched by Kai, the Library's AI content creator. Every item links to the moment it comes from — click a timestamp to listen in context.

Written for:

Fetoscopic Tracheal Occlusion for Severe CDH: Timing, Technique, and Physiologic Rationale

The episode's teaching points arranged as a structured lesson, building from the basics up to the finer points. Written by Kai from the episode transcript and reviewed before publishing.

For trainees · Teaching arc · AI-written, human-reviewed

This discussion walks through the technical and conceptual framework for fetoscopic endoluminal tracheal occlusion (FETO) in severe congenital diaphragmatic hernia, emphasizing the judgment calls that separate competent execution from expert management.

Severity determines candidacy, not defect size

The first non-obvious point: imaging cannot precisely determine the size of the diaphragmatic defect 1:29. What matters is not the anatomic defect but the physiologic consequence. Ultrasound screens for CDH 1:40; MRI provides higher resolution and crucially provides information about fetal pulmonary status 1:48. The severity spectrum moves from mild (left lung shrinkage alone 2:05) to moderate (intestines and partial liver herniation with smaller left lung 2:11) to severe (significant liver herniation, very small left lung, and compressed right lung 2:24). Severe cases—where the liver occupies a good portion of the chest and both lungs are compromised—are the candidates for FETO 2:35. The teaching point is that you are treating lung hypoplasia, not hernia size.

The therapeutic window is narrow and non-negotiable

FETO is performed between 27 weeks and 29 weeks 6 days gestational age 2:44. This is not a range of convenience. Earlier placement risks inadequate lung maturity to respond; later placement leaves insufficient time for the intervention to work before the lungs must function. The balloon is left in place for several weeks to accelerate lung growth 4:12, with removal attempted around 34 weeks gestation 4:18. The math is tight: you need roughly five weeks of occlusion to see benefit, but the balloon must come out before delivery to allow the airway to clear and the lungs to prepare for air breathing. Missing either end of this window compromises the intervention.

Balloon position is anatomically precise

The fetoscope must reach "the main trachea below the vocal cords but above the carina before the trachea splits into the two main bronchi" 3:27. Too high and you risk vocal cord injury or inadequate occlusion; too low and you occlude one bronchus preferentially, creating asymmetric lung development. The balloon is "inflated to completely occlude the trachea" 3:38—partial occlusion is failure. This is not a forgiving procedure; the target zone is millimeters in a moving fetus.

The mechanism is pressure-driven, not structural

Fetal lungs produce fluid that normally exits through the trachea 3:48. Occlude the trachea and fluid accumulates, building pressure that promotes lung development 3:52. The exact mechanism remains unclear, but the clinical observation is that sustained intraluminal pressure promotes alveolar and vascular development. This is not about stretching the lung mechanically; it is about creating a sustained physiologic stimulus. The implication: partial occlusion or early balloon migration negates the benefit.

Balloon removal is technique-dependent

If fetal position allows, the balloon is punctured under ultrasound guidance and expelled by lung fluid without risk 4:33. If position is unfavorable, a grasper holds the balloon during needle puncture, then removes the deflated balloon 4:40. The teaching point: you must have a removal plan before you place the balloon. A balloon that cannot be removed before labor is a disaster—it converts a planned intervention into an emergent airway crisis at delivery.

The goal is term vaginal delivery

Vaginal delivery at term is ideal, with cesarean section reserved for standard obstetrical indications 5:02. FETO is not an indication for operative delivery. The mother and fetus are monitored carefully for the remainder of pregnancy 4:56, but the aim is to normalize the trajectory—to convert a severe CDH with poor prognosis into a moderate CDH that can be managed postnatally. The procedure succeeds when it makes itself unremarkable at delivery.

Takeaways from this story

FETO candidacy depends on lung hypoplasia severity, not hernia size—MRI assessment of pulmonary status drives the decision.
The therapeutic window is 27-29+6 weeks for placement and 34 weeks for removal—missing either endpoint compromises the intervention.
Balloon position must be in the main trachea below vocal cords but above the carina; millimeters matter in a moving fetus.
Sustained tracheal pressure from trapped lung fluid drives lung development—partial occlusion or early migration negates benefit.
Plan balloon removal before placement; a balloon that cannot be removed before labor creates an emergent airway crisis at delivery.

Fetoscopic Tracheal Occlusion for Severe Congenital Diaphragmatic Hernia

The episode's main topic retold as a plain-language walkthrough — what it is, why it matters, and what the speakers concluded. Written by Kai from the episode transcript and reviewed before publishing.

For the care team · Explainer · AI-written, human-reviewed

Why This Exists

Congenital diaphragmatic hernia exists on a severity spectrum, and imaging cannot reliably predict which fetuses will survive 1:29. In mild cases, the left lung shrinks modestly as abdominal contents herniate 2:05. In moderate cases, intestines and part of the liver push upward, further compressing the left lung 2:11. In severe cases — the ones that drive fetal intervention — the liver occupies much of the chest, the left lung is profoundly hypoplastic, and even the contralateral right lung is compressed 2:24. These severe cases are the candidates for fetoscopic endoluminal tracheal occlusion, or FETO 2:35.

The problem is not the diaphragm defect itself, which can be repaired after birth. The problem is that the herniated viscera prevent normal lung development during the critical window of gestation. By the time the baby is born, the lungs may be too small and too poorly vascularized to sustain life, even with optimal postnatal care. FETO attempts to reverse this trajectory in utero.

The Core Problem

Ultrasound typically identifies CDH prenatally, but MRI provides the resolution needed to assess pulmonary status and guide intervention decisions 1:40 1:48. The challenge is that prenatal imaging cannot precisely measure the size of the diaphragm defect 1:29. What matters clinically is not the hole size but the degree of lung compression and the extent of liver herniation. Severe cases — defined by substantial liver herniation and bilateral lung hypoplasia — carry high mortality without intervention.

How the Approach Works

FETO is performed between 27 weeks and 29 weeks 6 days gestation 2:44. The timing is deliberate: early enough to allow meaningful lung growth before delivery, late enough that the fetus can tolerate the procedure and the risks of preterm labor it may trigger.

The mother receives local anesthetic 2:58. Under ultrasound guidance, an introducer is inserted into the amniotic space, through which a fetoscope — a small-caliber camera — is advanced 3:04. The fetoscope is navigated to the fetal mouth and then carefully into the trachea 3:16. The target position is precise: below the vocal cords but above the carina, in the main trachea before it bifurcates into the bronchi 3:27. A balloon is then inserted through the fetoscope, inflated to completely occlude the airway, detached, and left in place 3:38.

The mechanism is counterintuitive. Fetal lungs continuously produce fluid that normally drains through the trachea 3:48. Occluding the trachea traps this fluid, building pressure within the airways 3:52. That pressure — through pathways not fully understood — stimulates lung growth and alveolar development. The balloon remains in place for several weeks 4:12.

At approximately 34 weeks gestation, the balloon must be removed to allow the lungs to drain and mature before delivery 4:18. If fetal positioning permits, the balloon is punctured under ultrasound guidance; lung fluid then expels the deflated balloon into the amniotic space, where it poses no risk 4:26 4:33. If the fetus is malpositioned, a grasper is used to stabilize the balloon during puncture, and the deflated balloon is retrieved fetoscopically 4:40. The pregnancy is then monitored closely until delivery 4:56, ideally vaginal and at term, with cesarean section reserved for standard obstetric indications 5:02.

What Remains Uncertain

This discussion does not address patient selection criteria beyond "severe CDH," nor does it quantify what degree of liver herniation or lung hypoplasia qualifies. It does not cover the risks of the procedure — preterm premature rupture of membranes, preterm labor, or the consequences if the balloon cannot be removed. It does not discuss outcomes: survival rates, need for ECMO, long-term pulmonary function, or how FETO compares to expectant management in randomized trials. The mechanism by which tracheal occlusion promotes lung growth is acknowledged but not explained.

When to Involve This Team

The discussion does not specify referral criteria or timing. In practice, any fetus with CDH diagnosed on prenatal ultrasound warrants MRI and evaluation at a fetal care center capable of both FETO and high-level neonatal CDH management. Severe cases — those with significant liver herniation and profound bilateral lung hypoplasia on MRI — should be referred early enough to allow intervention in the 27-29 week window if the family and team decide to proceed. This is not a procedure performed in community hospitals; it requires a multidisciplinary fetal surgery program with fetoscopic capability, maternal-fetal medicine expertise, and a neonatal intensive care unit experienced in CDH.

Takeaways from this story

FETO targets severe CDH with liver herniation and bilateral lung hypoplasia, performed at 27-29+6 weeks gestation.
Tracheal occlusion traps fetal lung fluid, building pressure that stimulates lung growth over several weeks.
Balloon removal at 34 weeks is critical and done either by ultrasound-guided puncture or fetoscopic retrieval.
Prenatal imaging cannot measure diaphragm defect size; MRI assesses lung compression and liver herniation instead.

FETO for Severe CDH: From Observational Management to Timed Intervention

How thinking and practice on this topic have changed over time, as told in this episode. Written by Kai from the episode transcript and reviewed before publishing.

For specialists · How the thinking changed · AI-written, human-reviewed

The Era of Expectant Management

Severe left-sided congenital diaphragmatic hernia with extensive liver herniation once meant watching and waiting 2:24. The defect was identified on prenatal imaging — ultrasound for screening, MRI for higher-resolution assessment of pulmonary status 1:40 1:48 — but the size of the diaphragmatic hole itself remained difficult to quantify with any imaging modality 1:29. Clinicians tracked the progressive compression: first the left lung shrinking as intestines herniated, then in moderate cases part of the liver pushing upward, and finally in the most severe presentations the liver occupying much of the chest with both lungs compromised 2:05 2:11 2:24. The fetus was delivered at term when possible, and the surgical team managed what they found at birth. This approach was not nihilism — it reflected the technical limits of intervening safely in utero and uncertainty about whether any prenatal manipulation would improve outcomes enough to justify the risks.

What Changed

The driver was accumulated evidence that tracheal occlusion could accelerate lung growth in the most severe cases. The mechanism rested on fetal lung physiology: lung tissue constantly produces fluid that normally drains through the trachea, but occluding the airway traps that fluid, building pressure that appears to promote pulmonary development 3:48 3:52. Fetoscopic technique made it possible to place and later remove a balloon in the fetal trachea without open hysterotomy. The procedure became standardized: insertion at 27 to 29 weeks and 6 days, balloon left in place for several weeks, removal at approximately 34 weeks 2:44 4:12 4:18. The timing window reflects a balance — early enough to drive meaningful lung growth, late enough to minimize prematurity risk if complications force early delivery, and removal timed to allow lung fluid dynamics to normalize before term.

Current Practice

Fetuses with severe CDH — liver occupying substantial chest volume, left lung very small, right lung beginning to shrink — are now considered good candidates for FETO 2:24 2:35. The procedure is performed under local anesthesia to the mother 2:58. An introducer is placed into the amniotic space under ultrasound guidance, a fetoscope is advanced through the fetal mouth into the trachea, and the balloon is positioned in the main trachea below the vocal cords but above the carina 3:04 3:16 3:27. The balloon is inflated to completely occlude the airway, then detached and left in place 3:38.

Removal at 34 weeks uses one of two approaches depending on fetal position. If the fetus is favorably positioned, the balloon is punctured under ultrasound guidance; lung fluids push the deflated balloon out of the trachea without further intervention 4:26 4:33. If positioning prevents needle access, a grasper is inserted fetoscopically to hold the balloon during puncture, then the deflated balloon is withdrawn with the grasper 4:40. After removal, the pregnancy is monitored closely with the goal of vaginal delivery at term, cesarean section reserved for standard obstetric indications 4:56 5:02.

What Remains Unsettled

The discussion does not address several questions that practicing specialists face. The degree of benefit in moderate CDH — where the left lung is compressed but the right lung remains relatively spared — is not discussed, nor is the threshold that separates a moderate case from a severe one in practical terms. The complication profile of FETO is not detailed here: rates of preterm premature rupture of membranes, preterm delivery, and the rare but serious risk of balloon migration or failure to retrieve the balloon are absent from this account. The long-term pulmonary outcomes — whether FETO-treated infants have different rates of chronic lung disease, pulmonary hypertension, or need for ECMO compared to expectantly managed severe CDH — are not addressed. Finally, the imaging difficulty noted at the outset 1:29 means that case selection still involves judgment calls about severity, and the discussion does not describe how centers handle borderline cases or what happens when prenatal severity assessment proves inaccurate at delivery.

Takeaways from this story

FETO is performed at 27-29+6 weeks, balloon removed at 34 weeks — timing balances lung growth benefit against prematurity risk
Balloon placement targets main trachea below vocal cords, above carina; complete occlusion traps lung fluid to drive growth
Removal technique depends on fetal position: ultrasound-guided puncture if accessible, fetoscopic grasper retrieval if not
Severe CDH candidates show liver occupying substantial chest volume with bilateral lung compression on prenatal imaging

Topic overview

A pediatric surgery podcast episode explaining fetoscopic endoluminal tracheal occlusion (FETO) for severe congenital diaphragmatic hernia. Dr. Fung Lim, surgical director of the Fetal Care Center at Cincinnati Children's, describes the procedure performed at 27-29+6 weeks gestation, in which a balloon is placed in the fetal trachea to occlude it and promote lung growth through fluid accumulation. The balloon remains in place for several weeks before removal at approximately 34 weeks, with the goal of improving pulmonary outcomes in fetuses with severe CDH where the liver occupies significant chest space and both lungs are compressed.

Key takeaways

FETO is performed at 27-29+6 weeks gestation for severe CDH with significant liver herniation and bilateral lung hypoplasia.
Tracheal occlusion causes fluid accumulation that accelerates fetal lung growth through increased intraluminal pressure.
The balloon remains in place for several weeks and is removed around 34 weeks gestation via ultrasound-guided puncture or fetoscopic retrieval.
Severe CDH is characterized by liver herniation into chest, marked left lung hypoplasia, and contralateral right lung compression on prenatal imaging.
Ideal balloon placement is in the main trachea below vocal cords but above the carina to achieve complete tracheal occlusion.

Keywords

congenital diaphragmatic hernia CDH fetoscopic endoluminal tracheal occlusion FETO ultrasound MRI tracheal occlusion C-section vaginal delivery local anesthetic Cincinnati Children's Hospital Medical Center Children's Mercy at Kansas City

Hashtags

#FetalSurgery #CongenitalDiaphragmaticHernia #PrenatalIntervention #PediatricSurgery

Transcript

Click "Show Transcript" to view the full text (5106 characters)

Hey there, listeners. This is Rob Gerardo, research resident at Cincinnati Children's Hospital Medical Center. Whether you're watching us on YouTube, listening to us on Apple Podcasts, Stitcher, Spotify, SoundCloud, the best way to listen is on the Stay Current Pediatric Surgery app. It's brought to you by Cincinnati Children's Hospital Medical Center, Children's Mercy at Kansas City, and the Journal of Pediatric Surgery. It's in the Apple App Store, it's in the Google Play Store. Download it today, but until then, Enjoy the episode. Do you guys remember a few years back when there's that meme going around the internet? Everyone was freaking out that they did surgery on a grape? Well, I had that same feeling of amazement when I found out that we can do surgery on a fetus, like an intrauterine fetus. To learn more about that, we're gonna hear from Doctor Fung Lim. He's the surgical director of the Fetal Care Center at Cincinnati Children's Hospital Medical Center. And we're gonna do a few of these episodes, but for this first one, we're gonna talk about how they treat congenital diaphragmatic hernia, intrauterine. Here's Doctor Lim. This animation shows a prenatal intervention of a congenital diaphragmatic hernia or CDH using phytoscopic endoluminal tracheal occlusion or fetal. One thing to note is that it's difficult to determine with imaging exactly how large the hole in the diaphragm is. When he says imaging, he means ultrasound and MRI. Now, ultrasound is usually the screening tool that we can use to find congenital diaphragmatic hernia in the fetus. But if you want the higher resolution imaging, you have to get the MRI. From that, you can get a lot of information about the pulmonary status of the fetus. What you are seeing here is a fetus who has no defect in the diaphragm and the anatomy is normal. In a mild diaphragmatic hernia as shown here, the left lung starts to shrink in size. Moving up the scale of severity, next we see a fetus with moderate diaphragmatic hernia. The left lung is getting smaller as the intestines and part of the liver push upwards. In the most severe cases, as shown here, the liver is occupying a good portion of the chest. The left lung is very small and even the right lung is shrinking. Now, fetuses with this severity of CDH are good candidates for feto. So, Doctor Lim, when is this procedure performed? The tracheal occlusion procedure is commonly performed at the gestation age of between 27 weeks and 29 weeks and 6 days. Anesthesia is induced by ultrasound guidance. A local anesthetic with numbing medication is injected into the mother. We then insert an introducer into the amniotic space. This allows us to place a feedoscope or a small camera through the introducer into the amniotic space. Once we locate the baby's mouth, we advance the fetoscope carefully into the fetal trachea or the windpipe, ensuring the scope is in good position. The ideal position is in the main trachea below the vocal cords, but above the carina before the trachea splits into the two main bronchi. We then insert a balloon into the airway. The balloon is inflated to completely occlude the trachea before it is detached and left in place. Because think about it, the fetal lung tissue is constantly creating this fluid. That escapes through the trachea normally, but if we occlude the trachea, then that fluid will continue to build up, the pressure will build up in that trachea, and for some reason, that seems to help the lungs develop. We confirm the proper position of the balloon before the feetoscope is removed. How long is the balloon left in place? The balloon is left in place for a few weeks to accelerate lung growth. Usually at about 34 weeks gestation, then we're gonna try and get rid of this balloon, and there are two ways to do that. If the baby is in proper position, we can puncture the balloon under ultrasound guidance as shown here. The deflated balloon is pushed out of the baby's trachea by the lung fluids and poses no risk to the baby's health. And if the baby's position doesn't allow for a needle puncture, we use a grasper to hold onto the balloon while a needle punctures the balloon. The deflated balloon is then removed from a baby's airway using the grasper. The mother and fetus are then monitored carefully for the remainder of the pregnancy. Ideally, the baby is delivered vaginally a term with a C-section reserved for the usual obstetrical reasons. So there you have it, one of many fetal procedures that we can do with advances in technology these days. So, did you hate this? Did you love it? Either way, leave us a comment, no matter where you are, whether you're on YouTube, Apple Podcasts, Stitcher, Spotify, SoundCloud, or the stay current pediatric surgery app. Download it today. It's in the Apple App Store, it's in the Google Play Store. If you're on YouTube, like and subscribe to our channel. We got a lot more video podcasts like this, and we got some great content cooking for you in the future. So, until next time, I'm Rod from Cincinnati Children's, and remember, knowledge should be free.

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