Dr pramod sarwaDr jayanth kumar

History of fetal surgery1965-first intrauterine transfusion…. A.W.Liley

1974-fetoscopy …. Hobbin

1981-fetoscopic transfusion…… Rodeck

1982-first open fetal surgery for obstructive uropathy by Dr. Michael Harrison (father of open fetal surgery), University of California, San Francisco

What is fetal surgeryIt is application of established surgical

techniques to the unborn baby -During gestation - At the time of delivery

Fetal surgery -prerequisitesLesion diagnosed accurately severity is assessed correctly defined natural history

Associated anomalies are excluded

Maternal risk is acceptably low

Neonatal outcome would be better than with surgery performed after delivery

fetal surgerycontraindicated

Chromosomal and genetic disordersOther associated life threatening abnormalities

Timing Usually performed between 24-29 weeks

gestation

Requires combined expertise ofObstetricianAnaesthesiologistNeonatologistPediatric surgeon

Indications

obstructive uropathy Congenital diaphragmatic

hernia Cardiac anomalies- complete heart block,

AS, PS Neural tube defects Thoracic space occupying

lesions Giant neck masses Tracheal atresia-stenosis Congenital adenomatoid

malformation (CCAM)

1. Anatomic lesions that interfere with development:

2. Anomalies associated with twins

• TTS- twin-twin transfusion

syndrome• TRAP- twin reverse arterial

perfusion

3. Anomalies of placenta, cord or membranes

• Amniotic band• Chorioangioma

Types of fetal surgeryOpen surgeryFETENDO-Fetal endoscopic surgery or

fetoscopy or minimally access fetal surgery (MAFS)

FIGS-Fetal image guided surgeryEXIT-Ex-utero intrapartum treatment

procedure

Open surgeryMost definitive and most invasivePerformed – middle of pregnancyMother anaesthetised by GAUterus opened similar to LSCSIntraoperative sonography – locate the placentaIncision taken close to the area of interestFetal part is exteriorizedSurgical repair of fetus done

Indication for open fetal surgeryDefect Treatment

CCAM (Congenital cystic adenomatoid malformation of lung)

Lobectomy

SCT (Sacro-coccygeal teratoma) Resection

MMC (Meningomyelocele) Repair

CDH Temporary tracheal occlusion

Obstructive hydronephrosis Vesicostomy, ureterostomy

FETENDO-fetal endoscopic surgery or MAFSFetoscopic access to the fetusDuring or after the 18th week of pregnancy Useful for treating placental problemsTechnically difficultMaintains fetal positionUnder LA with infiltration of both skin and

peritoneum+/-sedationUnder epidural, spinal or CSE anaesthesiaHigh risk for urgent C-section: CSE preferredSedation required for maternal anxiolysis

FetendoAdvantagesLess invasiveAvoids maternal hysterotomyLess risk of amniotic fluid leakLess blood lossLess preterm labour and uterine ruptureDisadvantagesUterus irrigated with NS – absorbed to peritoneum

through fallopian tubes – pulmonary oedema as mother also receives tocolytics. This can be treated with diuretics

Defect TreatmentE.g. CDH( Congenital diaphragmatic hernia)

Balloon occlusion of trachea

TTTS (Twin-twin transfusion syndrome)

Laser coagulation of vessels

Acardiac twins in TRAP sequence (twin reverse arterial perfusion)

Cord ligation

ABS-Amniotic band syndrome Division of amniotic bands BOO-Bladder outlet obstruction Vesicoamniotic shunt

FIGS - fetal image guided surgeryCombination of endoscopic and sonographic

methodUltrasound image guided procedureDone under RA or LA

AdvantagesLeast invasiveLeast risk of amniotic fluid leak of preterm labour

Both diagnostic and therapeutic usesDiagnostic Therapeutic

-Chorion villus sampling-Amniocentesis-Cordocentesis-Fetal skin biopsy

-RFA of anomalous twins-Cord cauterization in twins-Vesical/pleural shunts/catheter-Balloon dilatation of aortic stenosis

Ex-utero intrapartum treatment (EXIT) procedure OOPS-operation on placental supportIntervention occurring at the time of deliveryUsed in cases where baby’s airway requires

surgical interventionProvide the baby with patent airway that can

provide oxygen to the lungs after separation of placenta

Starts as a routine LSCS but under GA with maximum volatile agent(>2 MAC)

Head of the baby is delivered, but placenta is in situ

Baby gets oxygen from placenta via umbilical cord

Surgeon removes the occlusive device

Bronchoscopy of fetal airway

Endotracheal intubation done

If unsuccessful, then tracheostomy tube below the level of airway blockage is placed

Oxygen delivery to lungs confirmed

Umbilical cord is clampedBaby delivered

Defect Treatment

CHAOS – Congenital high airway obstruction syndrome

Tracheostomy

CDH (Congenital diaphragmatic hernia)

Removal of tracheal balloon

Giant cervical neck masses Resection

CCAM (Congenital cystic adenomatoid malformation)

Resection

Considerations during EXIT procedureUterus needs to stay relaxed to permit

placental perfusionUterus needs to contract at end to limit

bleedingNeeds hemostatic hysterotomyMay permit upto 2 hours of ongoing placental

perfusion

Challenges before the field of fetal surgeryEthical dilemmaMaternal riskFetal riskMaternal anaesthesiaFetal anaesthesiaPost surgical tocolysis

Anaesthesia -basic considerations

Pre operative evaluation and preparationRelief of anxietyAvoidance of fetal asphyxiaAdequate analgesiaUterine relaxationPrevention of preterm labourMaternal safetyAvoidance of teratogenic agentsFetal anaesthesia and monitoring

Fetal assessmentDetailed USG to rule out other malformationsFetal echocardiographyFetal MRI3D and 4D examinationDetail examination of affected organ systemAmniocentesisLocalisation of placenta and umbilical cordVolume of amniotic fluid

Pre-operative preparationConsent for caesarean deliveryMaternal blood cross matchedAvailability of O-negative, CMV-negative,

irradiated, cross matched blood against the maternal antibodies

Adequate aspiration prophylaxisIndomethacin rectal suppository for

postoperative tocolysisEpidural catheter-postoperative pain controlOperating room temp

Avoidance of fetal asphyxiaAvoidance of maternal hypoxiaAvoidance of maternal hypercapneaQuick treatment of maternal hypotension

Fluid bolusesVasopressorsDecreasing anaesthetic concentration

Adequate analgesiaLocal anaesthesia-0.5 ml 1% lidocaine-

infiltration of both skin and peritoneum

Field block

CSE

Prevention and treatment of preterm labourTocolytic agent

indomethacin (rectal)magnesium sulfateterbutaline (subcutaneous) nitroglycerine

Halogenated agents-halothane, isoflurane, sevoflurane

Vascular stasis during hysterotomy-special stapling device

Postoperative pain control-epidural catheter

Maternal sedation and local anaesthesiaIndicated in percutaneous needle aspirations

or catheter insertionsDrug of choice-BZD(diazepam, midazolam),

narcotics(fentanyl, remifentanil) for maternal anxiety

Disadvantages:increased hypoxiaunprotected airway; aspiration riskpresence of foetal movements

Close monitoring for 3-4 hrs required

Regional anaesthesiaIndicated in MAFS(Minimal access fetal surgery)Lumbar epidural, spinal or CSE anaesthesiaAdvantages:

excellent analgesia and good muscle relaxationavoids GAkeeps mother awake and alert

minimal effects on fetal hemodynamics, uteroplacental blood flow and uterine activity

Disadvantages:Hypotensionlack of fetal anaesthesia, difficulty manipulating

uterus and cord while the fetus may be moving

General anaesthesiaAspiration prophylaxis-sodium citrate, ranitidine,

metoclopramidePrevention of supine hypotensive syndrome-left

lateral tiltShort acting amnestic-thiopentoneShort acting muscle relaxant-succinylcholine for RSIMaintenance - 100% O2 with low levels of

inhalational(isoflurane) or 50% O2 and 50% N2O with low inhalational + vecuronium + fentanyl

Maternal and fetal monitoring

Uterus opened similar to LSCSFetal part is exteriorizedSpecial stapling deviceSurgical repair of fetus doneWarmed Ringer Lactate along with

antibiotics infused to replace amniotic fluid

At the time of closure, i.v. MgSO4 6 gm over 20 minutes

During extubation, coughing or straining avoided to maintain integrity of uterine closure

General anaesthesia• Advantages:

• Profound uterine relaxation• Allowing uterine manipulation with an

immobile anaesthetised fetus

• Disadvantages: • Fetal cardiac depression• Decreased uteroplacental blood flow

Maternal monitoringPulse oximeterECGHR BP monitoringCapnographyTemperature

Fetal monitoring Blood gas, pH, pO2Blood glucoseElectrolytesFetal Hb from cord bloodElectronic measurements of foetal

heart rate, blood pressure and umbilical blood flow

Foetal heart rate cardiotachometer-FHR, temperature

Foetal ECGFoetal echocardiography

Fetal anaesthetic considerationsFetal organ systems are immatureFetal cardiac output is sensitive to HR

changesFetus has high vagal tone and thus response

to stress with precipitous bradycardiaFetal circulatory blood volume is low, hence

little intra-operative bleeding can cause hypovolemia, so trigger for transfusion is low

During prolonged surgery, fetus need to be transfused O-negative blood

Fetal painNot possible to assess fetal pain directlyAssessed indirectly by ability of fetus to mount

a stress response to noxious stimulus-increased fetal cortisol, beta-endorphins and central sparing hemodynamic changes

Fetal administration of narcotic inhibits cortisol and beta-endorphin release but does not inhibit central sparing hemodynamic changes

Fetal stress to pain starts in 8 weeks gestation age and may cause preterm labour

Advantages of fetal surgeryIn utero environment supports rapid post-

operative healingRapid healing, fostered by fetal growth factorInfections are combated by passage of

maternal immune factorsUmbilical circulation meets nutritional and

respiratory needs without outside assistanceMedical agents given directly to fetus have

greater efficacy at reduced doses

Postsurgical tocolysisHigh risk of preterm labourPre-operative: rectal indomethacinMgSO4 is tocolytic of choice and maintained

for 2-3 days-3 gm/hr infusionAdequate maternal analgesia as maternal pain

can cause preterm labour and fetal distressEpidural analgesia (PCEA) for 24-48 hrs is

recommended to prevent uterine contractility

New researchesRemifentanil produces improved fetal immobilization

with good maternal sedation and only minimal effects on maternal respiration (Anesth Analg, 2005)

Continuous fentanyl infusion with midazolam provides acceptable maternal analgesia and sedation during fetoscopy(Masui, 2008)

In fetoscopic interventions under GA, cardiopulmonary functions remain stable. However, a moderate increase in extravascular lung water(EVLW) and pulmonary vascular permeability indicates an increased risk for maternal pulmonary oedema(Br J Anaesth, 2013)

Future possibilities Stem cells or DNA to treat sickle cell anaemia or other

genetic conditionsMore potent tocolytics to control preterm labourImproved techniques of fetoscopic visualisation