Selective laser photocoagulation of...

Selective laser photocoagulation of communicating utensils (SLPCV) is an application of minimally invasive endoscopic fetal surgery (ie, surgical fetoscopy) performed for morose cases of twin-to-twin transfusion syndrome (TTTS) a complication of monochorionic twin pregnancies. Advances in ultrasound and endoscopy have aided the identification and treatment of this potentially lethal or fatal condition. Surgical fetoscopy, an innovation in the field of surgery and maternal-fetal medicine, benefits patients by the agency of reducing the morbidity and mortality associated with TTT with minimal risks to the mother. AORN J 71 (April 2000) 796-810

A riddle exists for expectant couples who are faced with the prenatal diagnosis of a fetal or placental malformation that precludes normal intrauterine growth and disclosure The problem is compounded when these malformations are fatal before the fetus or fetuses have reached the age of viability and can be delivered and treated postnatally.(1) If left untreated, the fetal morbidity and mortality in these cases is extremely high, sometimes up to 100% for an diagnoses. The effect on family members facing these diagnoses is devastating. Advances in high resolution ultrasound and endoscopy allow for the identification and treatment in utero of a certain number of of these fetal conditions. Selective laser photocoagulation of communicating tubes (SLPCV) in twin-to-twin transfusion syndrome (TTTS) is illustrative of a fetoscopic application used to treat a condition in utero which otherwise deductions in extremely high fetal morbidity and mortality.

TWIN-TO-TWIN TRANSFUSION SYNDROME

Twin-to-twin transfusion syndrome is a major complication of monozygotic (ie, identical) twin pregnancies, occurring in 55% to 175% of monochorionic (ie, single placenta) gestations.(2)

DEFINITION AND PATHOPHYSIOLOGY

Identical twins usually share vascular communications in consequence of the placenta, but twins with TITS share abnormal vascular communications within their shared placenta. The condition appears to eventuate from an imbalance of family flow between the two fetuses.

Placental ducts are found in cotyledons, which are lobes onward the maternal surface of the placenta. Usually, the placenta has 15 to 28 cotyledons that also contain chorionic villi and intervillous space.(3) Usual TTT cases reveal that an artery from united twin supplies a placental cotyledon, which in employ is drained by a vein to the other twin. children is shunted from one twin--the donor--and transfused to the other twin--the recipient--through placental vascular anastomoses.(4) As a originate of this phenomenon, one twin (ie, recipient twin) receives too long blood, resulting in polyhydramnios (ie, too greatly amniotic fluid) and cardiac overload. The other twin (ie, donor twin) does not receive enough life-blood causing oligohydramnios (ie, too little amniotic fluid), anemia, and putting out retardation.(5) The desired outcome of the surgical correction includes resolution of the syndrome with equalization of amniotic fluid whirl and minimal risks to the mother and fetuses.

MANAGEMENT OF TWIN-TO-TWIN TRANSFUSION SYNDROME

Management of TTT in the past has been associated with a 100% perinatal mortality.(6) Invasive treatment options include serial amniocentesis (ie, amniodrainage), laser photocoagulation of communicating tubes selective feticide (ie, iatrogenic demise), or selective fetectomy (ie, removal of the fetus). Serial amniocentesis of the polyhydramniotic sac of the recipient twin has been associated with an overall 50% to 60% survival rate.(7) Risks associated with this technique include infection, break of membranes, and extra amniotic fluid collections with disruption of the membranes.(8) More significantly, the death of single of the twins has been associated with significant morbidity, including major neurological complications, of the surviving twin. It has been documented that the surviving twin has acute anemia, suggesting that perhaps the surviving twin experiences hypotension from acute bleeding into the twin who has died.(9)

Depending in succession the severity of the TTT the serial amniocentesis may ne to be performed as ofttimes as every other day. The reported incidence of fetal neurological complications associated with serial amniocentesis is approximately 25%(10) Trained surgeon can perform this transaction but it does not address the occasion of the problem, which is the kindred flow imbalance between the twins.

Laser photocoagulation of the communicating bottoms has been proposed as an effective surgical action to treat TTTS. The goal of surgery is to identify and interrupt the vascular anastomoses responsible for the imbalance of vital fluid flow.(11) The first fetoscopic laser occlusion of chorioangiopagus ducts (ie, the FLOC procedure) in a monochorionic twin pregnancy affected from TTTS was performed in 1988(12) Chorioangiopagus tubes are vessels that join the fetuses in the placenta. From a technical viewpoint, however, confusion existed regarding the particular identification of the communicating vessels