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doi: 10.1097/01.ORN.0000433528.41293.9d
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Maternal-fetal surgery: Increasing survival for the smallest of patients

Miesnik, Susan R. MSN, CRNP, RNC-OB; Jones, Tyra MSN, CRNP; Scully, Susan M. BSN, RN, CNOR; Chubb, Meredith BSN, RN

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At the Children's Hospital of Philadelphia, Philadelphia, Pa., Susan R. Miesnik is a perinatal nurse practitioner, Tyra Jones is a women's health nurse practitioner, Susan M. Scully is a general, thoracic, and fetal surgery specialty nurse, and Meredith Chubb is a registered nurse.

The authors have disclosed that they have no financial relationships related to this article.

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Before the routine use of screening ultrasounds in pregnancy, birth defects were typically discovered at the time of birth. Today, prenatal diagnosis of congenital anomalies, via ultrasound and other imaging modalities, has enabled therapeutic interventions, such as fetal surgery, to improve patient outcomes for neonates and children. This article will focus on minimally invasive surgical procedures for single and multiple gestation and open fetal surgery.

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Complications associated with single and multiple gestation

One out of every 33 neonates is born with a birth defect, with monochorionic multiple gestation at an increased risk for certain complications.1 Minimally invasive surgical procedures can be an option for singleton gestation when the fetus has been diagnosed with lower urinary tract obstruction, pleural effusion, congenital cystic adenomatoid malformation, or for the following multiple gestation complications: severe twin-to-twin transfusion syndrome; twin reversed arterial perfusion sequence; severe selective intrauterine growth restriction; and specific discordant malformations. Carefully selected cases may benefit from one of three minimally invasive procedures in an attempt to help the pregnancy result in at least one live birth. Every pregnancy is unique; there's no standard algorithm to follow regarding which procedure is most appropriate. This must be decided through careful deliberation by the fetal team, taking into consideration each case's distinctive characteristics.

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Minimally invasive procedures for single and multiple gestation

Minimally invasive procedures for single and multiple gestation include feto-amniotic shunt placement, selective laser photocoagulation, radio-frequency ablation (RFA) of umbilical cord flow, and bipolar umbilical cord coagulation (BCC). These are performed under procedural sedation using medications that sedate the mother and also cause fetal quiescence (a fetal behavioral state characterized by inactivity).2 A local anesthetic, such as 1% plain lidocaine, is injected into the maternal skin at the entry site to further decrease any possible discomfort. A small skin incision on the maternal abdomen is made with a #11 blade, and a sheath or trocar is used to puncture the uterus to gain access into the uterine cavity. Since the incision is only a few millimeters in length, a topical skin adhesive, steri-strips, and a transparent film dressing are sufficient to protect the site following surgery without hindering postoperative ultrasound studies. Patients are generally discharged later the same day or the following morning with instructions for continued bed rest. An appointment is scheduled to return for a follow-up fetal ultrasound 1 week after the procedure.

  • Feto-amniotic shunts are hollow, double-pigtailed coiled tubes that provide one-way drainage into the amniotic fluid. They are placed to decompress fluid-filled spaces in the fetal thorax, such as congenital cystic adenomatoid malformations (CCAMs) or pleural effusions that may result in severe morbidity, mortality related to pulmonary hypoplasia, or hydrops fetalis (an excessive accumulation of serous fluid in fetal tissues). Shunts are also used for lower urinary tract obstructions to decompress the distended bladder, decrease the risk of pulmonary hypoplasia, and reduce the risk of renal damage. In both cases, shunt placement is used to delay disease progression until after delivery when the neonate can receive definitive care. The shunt trocar, a 10-French sheath, is inserted through the maternal abdomen, uterine wall, amniotic sac, and into the fetal cavity. The shunt is slowly advanced through the trocar into the fluid-filled space. A push rod is used to advance the distal-coiled pigtail portion of the shunt as the trocar is slowly removed from the fetus. Once the trocar is removed, the proximal portion (pigtail) of the shunt is deployed so the distal end remains in the fluid-filled space while the proximal end is placed in the amniotic sac.
  • Selective laser photocoagulation is a procedure that involves using a laser to selectively coagulate communicating vessels on the placenta in an attempt to halt the unequal distribution of blood flow between the two fetuses.3 After the maternal patient is prepared and sedated, a 4 mm access port is placed into the maternal uterus to allow for an operative sheath that contains a fetoscope and laser fiber to be inserted into the amniotic cavity of one twin. The placental cord insertion site is visualized, and all vessels that originate from there are mapped to their endpoint. Any vessel that communicates with a vessel of the co-twin is laser photocoagulated. After all communicating vessels are coagulated, an amnioreduction is performed to reduce some of the excess amniotic fluid.

One of the most common lasers used for this procedure is a diode laser that produces a 940-nm wavelength. The laser beam is invisible, so a green pilot (targeting) light is used as a guide. Specific documentation is required for the laser to ensure laser safety protocols are adhered to. Protocols include having the appropriate laser goggles available for all personnel in the OR, including the patient, keeping the laser on standby at all times when not in use, and keeping a basin of sterile 0.9% sodium chloride on the sterile field for use in the case of fire. The circulating nurse needs to document the type of laser used, mode, wattage, joules, pulses, and time the laser was in use. The circulating nurse must also make sure the laser has been tested and is in proper working order prior to bringing the patient into the OR.

  • RFA of umbilical cord flow is the generation of heat from high-frequency alternating current to ablate blood flow within tissues of the affected fetus for selective fetal reduction in monochorionic pregnancies. RFA is preferred in cases where fetal tissue volumes are small, when the umbilical cord leading to the affected twin is short, or in cases of severe oligohydramnios or anhydramnios. The procedure can be safely performed under local anesthetic without the need for general anesthesia, since RFA doesn't cause maternal discomfort due to maternal nerves or heart muscles not directly being stimulated.

RFA uses four separate dispersive electrode grounding pads, preferably all with the same lot number, and placed on the patient's thighs, two on each thigh as indicated by the manufacturer. Using ultrasound guidance, a small, 17-gauge (1.4 mm diameter) radio-frequency probe is inserted in the abdomen adjacent to where the umbilical cord inserts into the affected fetus. The small diameter of the RFA sheath minimizes the risk of complications.4 When the sheath is in the proper location, the metal wire tines within the radio-frequency probe are deployed revealing an umbrella shape, measuring 2 cm (0.8 in) in diameter. The thermal effects from the radio-frequency generator are focused only within the 2 cm area within the tines of the selected area. The generator is enacted for 2 minutes at a time, progressing in 10-W increments. During this procedure, heat is produced, causing tissue coagulation and necrosis. The circulating nurse records each 2-minute cycle, wattage, and resistance (measured in ohms) as displayed on the generator. After each 2-minute application of specified wattage energy, color-flow Doppler of the umbilical cord and fetal heart rate are assessed. When the color Doppler shows complete absence of blood flow in the umbilical cord, the procedure is finished. The tines of the radio-frequency device are retracted back inside the RFA probe and removed from the maternal abdomen. The dispersive electrode grounding pads are removed, and the patient's skin is assessed for burns or breakdown.

  • BCC for selective feticide in complicated monochorionic twin pregnancies (the fetuses share a single placenta) is a minimally invasive procedure whereby a needle is guided by ultrasound into the umbilical cord to coagulate blood flow, interrupting blood communication between fetuses. This allows the remaining twin to progress without the complication of spontaneous death. BCC is preferred when the affected fetus is in an amniotic sac with significant amounts of amniotic fluid to allow instrument access or when monochorionic/monoamniotic fetuses require total cord transection to prevent complications from cord entanglement.4

Under ultrasound guidance, a 3.0 mm operative port is placed into the uterus, and a 2 mm endoscope is passed through the operative sheath. The endoscope allows the surgeon to determine the optimal site for coagulation on the affected fetus' umbilical cord. The endoscope is then removed, and a 3 mm bipolar coagulation forcep is introduced. The bipolar cautery forcep works by having an active electrode side and a return (or grounding) electrode side allowing energy to flow only between the two tips of the forcep. Ultrasound guidance is used to direct the forceps to the designated areas on the umbilical cord that are to be coagulated.

The bipolar generator is set between 80 to 100 W, and applications of bipolar energy of 30 to 60 seconds in length are expelled along two or three different sites on the umbilical cord. The circulating nurse should record each application of bipolar energy identifying the amount of energy used and the length of time energy was applied. Intraoperative ultrasound uses color flow Doppler to evaluate the effectiveness of the bipolar energy to end blood flow through the umbilical cord vessels. Once the blood flow has been successfully stopped, the bipolar coagulation forcep and port are removed. If transection of the umbilical cord is required, a 3 mm endoscopic scissor is inserted to cut the cord between two coagulated sections. When a surgical procedure results in the demise of one fetus, that fetus remains in the uterus and is gradually reabsorbed. Occasionally, rather than being completely reabsorbed, the demised fetus will be compressed to a flattened, parchment-like state known as fetus papyraceus. The loss of a twin may be distressing for parents. The psychological issues related to grieving for the lost twin while preparing for the birth of the surviving twin may be profound. The thought of still carrying the retained dead twin and the uncertainty regarding the long-term outcome of the surviving fetus may compound these issues. Social work and bereavement counseling may be indicated for these families.

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Open fetal surgery

Open fetal surgery is an option that can increase survival or long-term prognosis for fetuses with severe anomalies. Open fetal surgery requires the use of general anesthesia, followed by a maternal laparotomy and uterine hysterotomy to remove or repair the fetal anomaly. There are three particular congenital anomalies in which fetal surgery is most commonly performed. They include myelomeningocele, lung masses (CCAMs or bronchopulmonary sequestration [BPS]), and sacrococcygeal teratoma.

  • Myelomeningocele, also known as spina bifida, is one of the most common congenital anomalies of the central nervous system. A myelomeningocele is a failure of the spine to close during fetal development, resulting in herniation of the meninges into a sac on the fetus' back containing cerebrospinal fluid and neural tissue. If left untreated until after birth, it can lead to paralysis, severe hydrocephalus, intellectual disability (previously known as mental retardation), and urinary and bowel incontinence. As a consequence of the success of the National Institutes of Health/National Institute of Child Health and Human Development Management of Myelomeningocele Study, open fetal surgery for this particular anomaly has become a standard of care.5
  • Lung masses (CCAMs or BPS). A CCAM is a benign cystic lung mass usually isolated to one lobe of the lung. It has connections with the bronchopulmonary tree but doesn't function in normal gas exchange. When the CCAM becomes too large, it can cause severe mass effect within the fetal chest resulting in pulmonary hypoplasia, mediastinal shift, compression of the esophagus, compression of the great vessels, and hydrops secondary to cardiac compression. Hydrops fetalis has been shown to be a predictor of fetal death; therefore, open fetal surgery to remove a large CCAM or BPS is indicated when a fetus develops hydrops.6
  • Sacrococcygeal teratoma is the most common tumor found in newborns. It arises from the primitive knot, or Hensen node, of the coccyx and can range from being a primarily external mass, to having internal and external components, or to being entirely intraabdominal. A highly vascularized sacrococcygeal teratoma demonstrates a vascular steal phenomenon into the low resistant vessels within the mass that results in high output cardiac failure, polyhydramnios, placentomegaly, and hydrops fetalis. Open fetal surgery is only indicated for sacrococcygeal teratoma if the fetus develops hydrops or demonstrates other signs of distress, suggesting high likelihood of demise if the intervention isn't performed.6

Open fetal surgery is generally performed prior to 30 to 32 weeks gestation. Deep maternal general anesthesia is required to ensure complete uterine relaxation. The mother is positioned supine with a gel roll placed under her right or left hip to prevent the weight of the pregnant uterus from occluding major maternal vessels. This can cause compromised blood flow to both the mother and fetus. Patient positioning is important to facilitate venous return as well as to promote appropriate fetal position in relation to the placenta and operative site. A low transverse abdominal incision is made, and the uterus is exposed. Intraoperative ultrasound is used to confirm fetal position, location of the placenta, and appropriate placement of the uterine incision. Under ultrasound guidance, holding sutures are placed to secure the fetal membranes to the uterine wall, and the uterine incision (hysterotomy) is made. A specialized stapling device is used to open the uterus that compresses the myometrium to prevent bleeding and secure the fetal membranes into the hysterotomy. This specialized device uses absorbable staples that disappear before delivery and helps prevent membrane separations that can lead to premature rupture of membranes. A catheter is then placed in the uterus that instills a warmed physiologic solution of lactated Ringer solution that keeps the fetus warm and buoyant during the repair. It also keeps the amniotic fluid at a consistent level, thus, preventing compression of the placenta or umbilical cord as well as placental abruption. At this point, the anomaly and operative site of the fetus is exposed. An I.M. injection of fentanyl, atropine, and vecuronium is administered to the fetus as an additional form of anesthesia.7 A peripheral I.V. line is also placed at this time to allow preloading the fetus with blood and/or I.V. volume expansion prior to removal of the vascular tumor. This helps to minimize the cardiovascular consequences of removing the highly vascular mass. During the fetal procedure, a cardiologist performs continuous fetal echocardiogram to monitor the fetal heart rate and cardiac function as well as the cardiovascular status, such as volume and overall fetal well-being. Once the procedure is completed, the uterus is closed in two layers, and an omental flap is tacked down over the uterine incision as another form of protection and to promote healing of the hysterotomy site. The abdomen is closed, and the wound is covered with a transparent film dressing. Postoperatively, the maternal patient is started on a staggered regimen of tocolytic medications to prevent preterm labor and delivery. Initially, pain is managed with a patient-controlled epidural and then with oral opioids. Hospital discharge usually occurs on postoperative day 4 with the patient instructed to remain on strict bed rest for 3 weeks. The patient should return weekly for follow-up ultrasounds and prenatal visits, with delivery via scheduled cesarean section at 37 weeks gestation. Because of the location of the uterine hysterotomy, the patient should be informed that all future pregnancies will need to be delivered by cesarean section prior to active labor to prevent scar dehiscence or rupture.

Open fetal surgery involves multiple specialties, requiring the collaboration of a dedicated, multidisciplinary fetal team for optimal maternal and fetal outcomes. Team members may include a maternal-fetal surgeon, neurosurgeon (for myelomeningocele closure), one or two maternal-fetal medicine specialists, an ultrasonographer, obstetric advanced practice nurse, anesthesia attending and fellow, pediatric cardiologist, scrub person (nurse or surgical technologist), and two specialty-trained perioperative nurses. One perioperative nurse is designated the primary circulating nurse, with the other nurse functioning in either role depending on need. However, the second nurse always scrubs in toward the end of the case to count with the primary circulator due to the fact that closure of the uterus can progress quickly, and the scrub person needs his or her full attention at the field.

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Perioperative considerations

As with any surgery, there are particular nursing considerations and responsibilities that must be addressed during the perioperative period. Pregnancy is a hypercoagulable state due to increased maternal circulating blood volume, which can put patients at a greater risk than the general population for developing deep vein thrombosis (DVT). Compression boots must be placed on both lower extremities prior to the start of all fetal surgical procedures to prevent DVTs from occurring. An ultrasound is used prior to all cases to determine optimal maternal positioning based on fetal lie and placental location, as well as to help with maternal hysterotomy planning. In addition, attention to strict sterile technique is essential to prevent intrauterine infection, which can lead to maternal sepsis and fetal demise.

One of the most effective mechanisms the fetal surgical team can use to ensure informed consent and promote safe care for the complex maternal-fetal dyad is to conduct a preoperative team meeting the day before the surgery to discuss any concerns there may be for the upcoming surgery. The patient and family are invited to join the team meeting, review the procedure, ask any additional questions, and sign the surgical consent.

Appropriate team handoffs throughout the entire perioperative visit are essential for the safe care of maternal-fetal patients. Prior to entering the OR, a handoff between the patient's direct care nurse and the circulating nurse includes the patient's medical record number (MRN), age, weight, diagnosis, allergies, relevant past medical and surgical history, verification of surgical consent, medications, immediate concerns, peripheral access, and a two-nurse identification check. Upon entering the OR, a sign-in occurs between the circulating nurse and the anesthesia provider that includes verification of patient's name, date of birth, medical record number, allergies, procedure, American Society of Anesthesiologists (ASA) physical status, hypothermia risk, DVT prophylaxis, airway issues, and preoperative antibiotics given within 1 hour of surgical incision. Just prior to skin incision, there is a time-out for safety. Given the complexity of the procedure, a surgeon-led time-out is indicated. The team members introduce themselves, and the topics covered during the time-out should include patient's name, procedure, allergies, patient's position, procedure length, where the incision should be made, antibiotics administered, blood products available if necessary, essential imaging needed during the procedure, confirmation that all necessary personnel are present, necessary equipment available, and sterile counts of sponges, sharps, instruments, fire risks, appropriate prosthesis and/or implants available, and any questions or concerns the team may have prior to starting the procedure. Finally, there is a sign-out at the end of the procedure between the surgeon and circulating nurse that includes name of procedure performed; wound class grade; specimens sent (as appropriate); correct counts of sponges, sharps, instruments; and any equipment problems encountered during the procedure.

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Success is a team effort

The complexity of fetal surgical procedures requires a highly specialized, dedicated team that can work together efficiently, effectively, and safely. In addition, this multidisciplinary team must develop strategies to maintain their expertise, especially if their annual case volume is low. The team must also be available for their patients—24 hours a day/7 days a week—when emergency procedures or postoperative complications arise.

It's important that the development of a specialized team of nurses begins with a small, dedicated group of professionals who work together for a certain number of procedures to establish competency, ensure confidence, and maintain skill levels and trust within the team. All members of the team should routinely rotate through cases to ensure each professional maintains his or her experience and competency with these extremely complex, high-risk and low-frequency procedures (see Perioperative nursing education).

As fetal therapy programs are established across the country, perioperative nurses will continue to be afforded opportunities for involvement in this fascinating and rapidly expanding field of maternal-fetal surgery. Nurses must be knowledgeable about all aspects of the developmental embryology and physiologic consequences of the fetal diagnoses, why they are amenable to intervention, and the specific surgical procedures that are used for treatment.

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Perioperative nursing education8,9

Fetal surgery is a high-risk, low-volume procedure that requires specialized skill and precise communication among the multi-disciplinary team. Advances in technology allow healthcare simulation to be used to model an actual perioperative setting while enabling the learning and practicing of essential skills in a risk-free environment. Simulation provides a critical training component for this specialized team.

Prior to simulation of any fetal surgery scenario, didactic education is provided for the perioperative team. It includes a review of theory, pathophysiology, and surgical process. Team members from all disciplines who are involved in fetal surgery (nursing, surgery, anesthesia, cardiology, and obstetrics/gynecology) participate in each simulation. Simulation scenarios are developed based on the educational needs of the team, whether to introduce a new procedure, practice a new skill, or refine the team's response to an emergent situation. Simulations are crafted to be as realistic as possible. This led to the development of a “baby” with a myelomeningocele contained in a foam “uterus” nestled conveniently inside a pregnancy simulation model. Time is provided after the simulation for the entire team to debrief and discuss the events. Providing realistic simulations allows the perioperative team to reinforce teamwork and effective communication, develop problem-solving skills, and practice high-stress scenarios in the safety of a controlled environment. Providing an opportunity for the perioperative nursing team to familiarize themselves with the various equipment and instruments that will be used in an actual complex surgical procedure allows them to become comfortable with set-up, safety factors, and surgical flow. Between annual simulations, nurses on the fetal perioperative team are assigned to scrub or circulate for fetal surgery cases on a rotating basis. This ensures that all fetal surgery nurses have sufficient opportunity to maintain and refine their skill sets.

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REFERENCES


2. Gregory CL, Wright J, Schwarz J, Rakowski L. A review of fetal thoracoamniotic & vesicoamniotic shunt procedures. J Obstet Gynecol Neonatal Nurs. 2012; 41:(3):426–433.

3. Farrell J, Howell LJ. An overview of surgical techniques, research trials, and future directions of fetal therapy. J Obstet Gynecol Neonatal Nurs. 2012; 41:(3):419–425.

4. Bebbington MW, Danzer E, Moldenhauer J, Khalek N, Johnson MP. Radiofrequency ablation vs bipolar umbilical cord coagulation in the management of complicated monochorionic pregnancies. Ultrasound Obstet Gynecol. 2012; 40:(3):319–324.

5. Adzick NS, Thom EA, Spong CY, et al. A randomized trial of prenatal versus postnatal repair of myelomeningocele. N Engl J Med. 2011; 364:(11):993–1004.

6. Adzick NS. Open fetal surgery for life-threatening fetal anomalies. Semin Fetal Neonatal Med. 2010; 15:(1):1–8.

7. Myers LB, Cohen D, Galinkin J, Gaiser R, Kurth CD. Anaesthesia for fetal surgery. Ped Anesth. 2002; :12:(7):569–578.

8. Rauen CA. Simulation as a teaching strategy for nursing education and orientation in cardiac surgery. Crit Care Nurse. 2004; :24:(3):46–51.

9. Scully SM, Mallon M, Kerr JC, Ludzia-DeAngelis A. Fetal myelomeningocele repair: a new standard of care. AORN J. 2012; 96:(2): 175–195.

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