Fetal Surgery for Sacrococcygeal Teratoma Technique

Updated: Aug 16, 2017
  • Author: Eveline Shue, MD; Chief Editor: Hanmin Lee, MD  more...
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Technique

Approach Considerations

Fetal surgery for sacrococcygeal teratoma (SCT) remains challenging; it should be considered only in select fetuses with impending hydrops and performed only in experienced centers. [34, 35] The purpose of fetal intervention is to debulk the tumor, with the understanding that formal oncologic resection would be performed postnatally. [36] The key to successful fetal intervention is to identify fetuses before the onset of hydrops, as well as to identify fetuses who may best be served by early delivery rather than fetal intervention.

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Open Fetal Surgery

Fetal exposure for SCT resection is similar to what has been reported for other open fetal surgeries. [12]

The uterus is exposed through a Pfannenstiel incision. If the placenta is located posteriorly, the superior and anterior skin and subcutaneous tissue flaps are created, and a midline fascial incision is then created to expose the uterus (see the image below).

Gravid uterus is exposed through Pfannenstiel inci Gravid uterus is exposed through Pfannenstiel incision. Media file courtesy of Dr Douglas Miniati and Dr Payam Saadai, Division of Pediatric Surgery, University of California, San Francisco, School of Medicine.

An anterior hysterotomy is performed while the uterus remains in the abdomen. However, if the placenta is located anteriorly, the rectus muscles will have to be divided in order to prevent uterine vascular compromise as the uterus is lifted out of the abdomen to perform a posterior hysterotomy.

A large ring retractor is used to maintain exposure. [12]

Intraoperative sterile ultrasonography is used to delineate the position of the fetus and the placenta (see the image below), and continuous echocardiography is used to monitor fetal well-being throughout the operative procedure.

Intraoperative ultrasonography is used to mark ext Intraoperative ultrasonography is used to mark extent of placenta and position of fetus prior to hysterotomy. Media file courtesy of Dr Douglas Miniati and Dr Payam Saadai, Division of Pediatric Surgery, University of California, San Francisco, School of Medicine.

If the pregnancy is complicated by polyhydramnios and placentomegaly, the true edge of the placenta is not always appreciated with ultrasonography, and the hysterotomy should be planned even farther away from this edge.

Stay sutures are placed on the uterus, and a small hysterotomy is made, which is then extended with a stapler designed especially to be used on the uterus (see the image below). [37] This hemostatic stapler is used to secure the membranes to the uterine wall to prevent separation of membranes. The fetus is positioned so that the tumor is exposed through the hysterotomy.

Specially designed uterine stapler provides hemost Specially designed uterine stapler provides hemostasis and prevents separation of membranes during hysterotomy. Media file courtesy of Dr Douglas Miniati and Dr Payam Saadai, Division of Pediatric Surgery, University of California, San Francisco, School of Medicine.

A ”fetal cocktail,” which consists of a paralytic agent (either pancuronium or rocuronium) and fentanyl, is administered to the fetus with an intramuscular injection. A pulse oximeter is placed on the fetus to monitor fetal well-being (see the first image below). Intravenous (IV) access is obtained for administration of fluids, blood, or medication (see the second image below). Use of this strategy of fetal monitoring during open fetal surgery allows administration of fluids in response to changes in preload during the resection and may improve fetal survival. [38]

Pulse oximeter is placed on foot of fetus to ensur Pulse oximeter is placed on foot of fetus to ensure fetal well-being. Media file courtesy of Dr Douglas Miniati and Dr Payam Saadai, Division of Pediatric Surgery, University of California, San Francisco, School of Medicine.
Intravenous access is established in saphenous vei Intravenous access is established in saphenous vein of fetus before debulking of sacrococcygeal teratoma. Media file courtesy of Dr Douglas Miniati and Dr Payam Saadai, Division of Pediatric Surgery, University of California, San Francisco, School of Medicine.

The fetus is kept buoyant and warm in the uterus with continuous infusion of warmed lactated Ringer solution (LRS) into the uterus.

After the SCT is resected, a two-layer uterine closure is performed. However, before the uterus is completely closed, LRS is instilled into the uterus until ultrasonography shows that normal amniotic fluid volume has been restored.

An omental flap can be secured over the hysterotomy, and the fascia, subcutaneous tissue, and skin are closed.

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Ex-Utero Intrapartum Treatment Procedure

In some cases, early delivery of the fetus without SCT resection has led to adverse events between delivery and neonatal resection (eg, tumor hemorrhage and fetal exsanguination). In cases where delivery and tumor resection may lead to hemodynamic instability, the ex-utero intrapartum treatment (EXIT) procedure may be considered. EXIT to resection of fetal SCT may be considered for a fetus of 27-32 weeks’ gestation with a large vascular type I or II tumor requiring early delivery but in the absence of maternal contraindications. [22]

The EXIT procedure, originally developed to establish an airway in a fetus with airway compromise while the fetus was still connected to placental circulation for oxygenation, has been adapted to resuscitate fetuses with other anomalies who may experience instability during birth. [39] For fetuses with SCT, the EXIT procedure allows tumor debulking to interrupt the vascular steal phenomenon, which minimizes preoperative manipulation and trauma to the tumor. [22] The infant can be stabilized before definitive oncologic resection.

The EXIT procedure is performed with the mother under general anesthesia [40] to maximize uterine relaxation and uteroplacental blood flow. The hysterotomy, fetal monitoring, and IV access are performed as described for open fetal surgery.

After debulking of the tumor, the fetus is intubated and given surfactant before the umbilical cord is clamped. The hysterotomy, fascial, and skin closure are performed in the same fashion as the open fetal SCT resection.

Roybal et al [22] reported one survivor using this technique, with neurologic complications due to tumor invasion into the spinal canal. Surgeons at the University of California, San Francisco (UCSF), have treated two fetuses with EXIT to SCT resection, with a survival of 50% [23] ; one patient died of necrotizing enterocolitis and sepsis.

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Radiofrequency Ablation

Several centers have described salvage of hydropic fetuses with SCT with open fetal resection. However, preterm labor remains the Achilles heel of fetal surgery. To circumvent preterm labor and to decrease maternal morbidity associated with fetal intervention for SCT, minimally invasive techniques, such as radiofrequency ablation (RFA), have been described. [41]

This technique uses ultrasound guidance to target the vessels feeding the SCT to reduce tumor vascularity. An eight-prong LeVeen radiofrequency probe is deployed through a 15-gauge needle into an umbrellalike configuration to a diameter of 20-35 mm. [41] It delivers energy in a spherical volume to cause tissue and tumor necrosis.

RFA for SCT remains controversial. The potential risks of this procedure include gas embolization due to microbubbles, hyperkalemia caused by tissue necrosis, perineal damage, and hemorrhage.

In a report of four fetuses with SCT, RFA successfully reduced tumor vascularity in all cases. [41] However, intrauterine fetal demise due to hemorrhage into the tumor occurred in one case, and another fetus underwent termination after postoperative MRI showed fetal brain damage. The two remaining fetuses survived but had evidence of perineal damage at birth.

Lam et al reported using RFA to treat SCT in an 18-week-old fetus, but the fetus died 2 days postoperatively. [42] Ibrahim et al reported a fetus born with sciatic nerve injury and malformation of the acetabulum and femoral head after RFA for SCT. [43] A study from Korea [15] reported six cases of fetal SCT treated with RFA; five of the six patients survived, and one patient had left-leg palsy and fecal and urinary incontinence.

In summary, although RFA has been used as salvage therapy in fetuses who would have otherwise died, many of these patients were born with complications. The keys to successful treatment with RFA may be (1) limiting the extent of coagulation in any single attempt to prevent massive hemorrhage or perineal necrosis and (2) performing a series of limited ablations. [42, 41] RFA as a treatment modality for fetal SCT remains limited and problematic, and more studies are necessary to determine whether and how this technique should be used.

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Laser Ablation

Laser ablation for SCT was first described in 1996 at 20 weeks’ gestation. [44] The pregnancy was complicated by polyhydramnios but not by placentomegaly or hydrops. Two unsuccessful attempts were made at 20 weeks’ and 26 weeks’ gestation to ablate the main vessels feeding the SCT, but the infant survived.

In this technique, local anesthesia is infiltrated into the skin and subcutaneous tissues. [17] Cordocentesis is performed to deliver fetal anesthesia with fentanyl (15 µg/kg) and pancuronium (2 mg/kg). [17] This can also be delivered intramuscularly to the fetus. Under ultrasound guidance, a 1.9-mm 60° fetoscope is introduced into the amniotic cavity percutaneously through a sheath, and a 0.4-mm neodymium-doped yttrium-aluminum-garnet (Nd:YAG) laser fiber is used to coagulate the vessels. [44]

In a retrospective study of 12 patients undergoing fetal intervention for SCT, four patients underwent laser ablation, but only one patient survived. [16] In a case report, a 24-week-old hydropic fetus underwent percutaneous laser ablation for SCT but died 2 days after fetal intervention. [17] In another study, a 22-week-old fetus underwent percutaneous laser ablation of tumor vessels and survived.

An additional retrospective multicenter study identified five fetuses that underwent minimally invasive fetal intervetion for hydrops or cardiac insufficiency as a result of SCT. [33] Four of these five fetuses underwent laser ablation, and three of them were targeted vascular ablations. Survival for the fetuses that underwent fetal intervention was 40%, but many patients required multiple procedures because of the recurrence of hydrops, cardiac insufficiency, or both. 

Laser ablation for SCT, like RFA for SCT, represents the movement in fetal surgery toward minimally invasive techniques. However, the outcomes vary, and current experience is too limited to determine whether laser ablation will be effective in reducing mortality in fetuses with SCT.

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Postoperative Care

After the operative procedure, 6 g of magnesium sulfate is given IV as a loading dose, and a continuous infusion is maintained for tocolysis. An epidural infusion also prevents uterine irritability, and indomethacin rectal suppositories are given every 6 hours for tocolysis. Approximately 18-24 hours after the procedure, the mother is transitioned from a magnesium drip to oral nifedipine for tocolysis. A single dose of maternal betamethasone is given in anticipation of preterm delivery. [14]

Postoperatively, the fetus undergoes daily echocardiography and ultrasonography to assess for ductal constriction, fetal movement, amniotic separation, and volume of amniotic fluid.

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