Central Retinal Artery Occlusion
Central retinal artery occlusion (CRAO) is a medical condition that is characterized by loss of vision on account of the blockage of the central artery of the retina. A clot from the carotid artery or the heart is usually the cause for the sudden flow of blood to the retina. Patients suffering from hypertension or carotid artery disease or diabetes are likely to suffer this condition. Arteriosclerosis is another likely cause for Central retinal artery occlusion. Due to the blockage of the retinal central artery, there is sudden and painless loss of vision. Another less severe condition is when a smaller branch artery to the retina gets blocked. This leads to loss in vision that is not as severe as in the case of CRAO.
If not attended to immediately, central retinal artery occlusion can leave a person permanently blinded. It is essential to restore retinal blood flow. An ophthalmologist may try to reduce the pressure in the eye with glaucoma agents. The embolus is moved from the central retinal artery to a branch artery. A surgical procedure whereby a small amount of fluid is drawn from the eye is carried out sometimes. This can seek to lower the pressure in the eye. Laser treatment is also done to reduce swelling and improve vision in the case of branch vein occlusion. But in most cases, it is not easy to restore normal vision.
Tubal Reconstructive Surgery
Tubal reconstructive surgery is performed to reconstruct the fallopian tubes which are obstructed or tied intentionally. This procedure helps in restoring the normal functioning of the fallopian tubes. Fallopian tubes play an important role in the reproduction process. The matured egg released by the ovary travels through the tube and converges with the sperm to facilitate fertilization. The fertilized egg gets implanted in the uterus to form the embryo. Sometimes the tubes may get blocked due to scar tissue caused by a pelvic infection, endometriosis, or pelvic surgery. When there is an obstruction, the egg cannot reach uterus nor can the sperm meet the egg causing infertility. Tubal reconstruction is a surgical method performed to repair the Fallopian tubes and thereby improving the chances of conception.
Tubal reconstructive surgery is also considered by those women who have undergone sterilization via tubal ligation earlier, but would want to reverse it now for personal reasons. Surgical techniques to reconstruct the fallopian tubes are aimed at achieving patency without harming the tubal anatomy. Hence microsurgical technique is the most preferred choice in conducting the tubal reconstructive surgery.
HSG (hysterosalpingogram) test is performed prior to surgery to evaluate the abnormalities inside the fallopian tubes. HSG Test will reveal the presence of blockage in the fallopian tubes.
Laparoscopic procedure is performed with micro instruments; it is minimally invasive, causes fewer traumas and relatively requires less hospital stay. Not all problems can be corrected using laparoscopy; few cases require an elaborate surgical procedure called laparotomy. Laparotomy is a procedure that involves making a large cut on the abdomen. Through Laparotomy, the surgeon can view the organs clearly, remove the blockage and join the healthy parts of the tubes. This procedure is usually adopted in case of reversal tubal ligation. The choice of the procedure depends upon various factors such as severity of the blockage, location of the obstruction and length of the Fallopian tubes.
There are three types of tubal reconstructive surgical techniques followed by the doctors to repair the Fallopian tubes. The technique chosen depends upon the nature of the problem.
Tubal anastomosis: Tubal anastomosis is a surgical procedure that is normally performed to restore the function of fallopian tubes, which have been blocked by a previous sterilization operation. It is also called tubal ligation reversal or reanastomosis. Typically, sterilization procedure would have closed the mid portion of the tube that lies between the uterus and fimbrial end. Tubal anastomosis technique removes the blocked segment of the tube and joins the two remaining open segments to make it patent.
Tubal implantation: Tubal implantation is a surgical technique that is opted when the blockage is detected at the proximal end (where the Fallopian tube and uterus join). In such cases a new opening will be created in the uterus and a healthy portion of the tube will be inserted into the uterine cavity.
Salpingostomy: Salpingostomy is used in case of distal tubal occlusion, an obstruction near fimbrial end or near ovaries. Salpingostomy involves creating an opening into the Fallopian tube surgically. Salpingostomy is also effective for treatment of hydrosalpinges, a condition where fluid builds up in the tubes leading to an occlusion. Through salpingostomy, excess fluid can be drained and tubes can be cleared to allow normal functioning. Sometimes the problem may occur in the fimbrial region, an end portion of the Fallopian tube that is responsible for sweeping the egg into tube. In such cases fimbria is reconstructed through a surgery called fimbrioplasty.
Tubal reconstructive surgery success rates
The degree of success from surgery will depend upon the extent of tubal damage. Surgery works very well, if the adhesions are small and thin. However with dense adhesions the chances of pregnancy become remote. Age is an important factor that is taken into consideration before proceeding with surgery. Women below 35 years of age have fair chances of becoming pregnant within an year of tubal surgery.
Those who fail to conceive through tubal reconstructive surgery, or, are not right candidates for a surgery are advised to chose an alternative method called IVF or other assisted reproductive techniques.
Risks associated with tubal surgery
The biggest risk associated with tubal surgery is the possibility of developing ectopic pregnancy (tubal pregnancy). Tubal pregnancy is a serious issue and may prove fatal to the mother and hence should be removed as early as possible. Other risks include infection, bleeding, trauma to adjoining organs and also the risk associated with anaesthesia.
Fetal surgery refers to the surgical treatment of the developing baby in the womb to rectify congenital defects. Surgery of the fetus is performed to fix the prenatally diagnosed anomalies. However fetal surgery is a complicated procedure and comes with lot of risks to both mother and the baby. Yet, doctors recommend fetal surgery, if the risks associated with continuing the pregnancy, without surgical intervention, outweighs the risks that come with fetal surgery. Certain abnormalities, if left to progress in the womb, may turn fatal and infant may die soon after the birth. However fetal intervention is initiated only after taking the safety of the mother into consideration. The common risks that are associated with fetal surgery are premature delivery, infection of the uterus, leaking of amniotic fluid through the membrane, potential infertility and the risk of anesthesia.
There are various techniques followed to diagnose fetal anomalies. The diagnostic method can be non invasive such as ultrasound, fetal echocardiography, MRI, Radiography, Measuring MSAFP (maternal serum alpha-fetoprotein) and Measuring maternal serum beta-human chorionic gonadotropin (HCG) or invasive procedure such as amniocentesis, Chorionic villus sampling and Percutaneous umbilical blood sampling (PUBS) are used to detect the birth defects.
Types of Fetal Surgery
Depending on the incision level, fetal surgery is classified into three types.
Open Fetal Surgery
Open fetal surgery is almost similar to cesarean section and involves a total opening of the uterus. In this type of surgery, a long incision is made in the mother's abdomen and then on the uterus to reach the fetes. Once the surgical correction is performed on the fetus to treat the birth defect, the uterus and abdominal is closed back leaving the fetus intact. Open fetal surgery is performed under general anesthesia. Surgery is performed using special instruments containing staples to prevent bleeding from uterus. During the operation, warm saline water is infused to maintain the position of placenta and umbilical cord and surgeon will keep a vigil on the pulse and heart rate of the baby with the help of the oximeter. After the surgery, the mother is hospitalized for close to a week to facilitate close monitoring. One should remember that, with open fetal surgery, mother will forgo the option of vaginal delivery for the present and future deliveries. She can deliver the baby only through C-section. She may be given some medication to avoid pre term labor. Open fetal surgery is followed for the conditions like chest mass, neck mass, spinbifida, myelomeningocele and Sacrococcygeal teratoma (SCT) (a tumor at the base of the child's tail bone).
There is one more variation to the open fetal surgery called the EXIT (Ex Utero Intrapartum Treatment) Procedure. EXIT surgery is performed at the end of the full term and just before the delivery. In this method the baby is partially delivered by bringing out only a part of the fetes from uterus and keeping rest of the fetes attached to placenta and umbilical cord to allow blood circulation. Once the defect is rectified, the baby is delivered fully. Exit procedure is essentially followed to correct the airway blockage in the baby.
Fetoscopic surgery is minimally invasive and unlike open fetal surgery, fetes remains inside the uterus while operating. Surgeon uses special instruments such as laser and makes a small incision with the help of the fetoscope to correct the birth defects. Fetoscopic surgery has shown high success rate in conditions such as Twin-Twin Transfusion Syndrome (TTTS), Twin Reversed Arterial Perfusion (TRAP), Amniotic band syndrome, and Tracheal occlusion for CDH. Fetoscopic surgery does not pose a risk of pre term labor and also eliminates most of the risks associated with open fetal surgery. This is essentially why fetoscopic surgery is the preferred choice, yet one should note that few complicated birth defects can be corrected only through open fetal surgery.
Fetal image guided surgery
Fetal image guided surgery is the least invasive of all wherein surgery is performed with the guidance of images of fetus produced on the external screen by ultrasound. Very thin instruments are inserted through a small opening in the abdomen and the correction is made without any endoscopic view and the whole procedure is guided by the sonogram images.
Various congenital conditions treated through fetal intervention
Congenital diaphragmatic hernia (CDH): Congenital diaphragmatic hernia (CDH) refers to the opening in the diaphragm through which the contents of the abdomen enter the chest cavity leaving no space for the lungs to develop properly. This is a serious condition and may lead to respiratory failure after birth. This condition, depending upon its severity, is treated through fetal intervention.
Spina bifida: Spina bifida refers to a condition wherein spinal column of the baby does not close properly around the spinal cord and the nerves start to protrude through the opening. Spina bifida can range from mild to severe form, and the severe cases lead to serious neurological problems after the birth. Only the severe form of spina bifida like Meningocele and Myelomeningocele call for fetal intervention through open fetal surgery.
Neck masses: Neck masses are the tumors of the neck that may obstruct the airway and esophagus of the child and also increase the level of amniotic fluid surrounding the baby. Typically, tumors of any kind are treated after birth. In rare cases they grow very large and may even cause heart failure. In such cases fetal intervention becomes necessary to remove the tumors.
Lung lesions: Lung lesions refer to the abnormal growth of lung tissue and these lesions can be cystic (fluid filled) or solid. There are various types of lung lesions and treatment depends upon their size and location. During pregnancy, continuous monitoring is necessary to keep vigil on the size of the lesion. Most often lung lesions shrink and make way for normal development. Lesions of smaller and moderate size are best treated after delivery. But if the size of the lung tumor is abnormally huge and poses a risk of hydrops (excess accumulation of fluid in the fetus) fetal intervention is initiated. Cystic lesions are normally removed through needle aspiration under the constant guidance of ultrasound images, but solid lesions require more elaborate procedure such as EXIT.
Congenital heart diseases: Not all congenital heart defects call for fetal intervention. Sometimes the septum (wall separating the right and left side of the heart) of the heart develops a hole while in the womb. However septum defects are typically treated after the birth of the child and rarely require fetal surgery. But if the heart develops severe obstructive cardiac disorders such as aortic stenosis, pulmonary stenosis and coarctation of the aorta,a fetal image-guided procedure may be necessary to open or enlarge the narrowed valve. This procedure involves placing a balloon catheter by inserting it through the uterus and into the fetal’s heart.
Amniotic Band Syndrome: This is a condition where fetus is entrapped in fibrous amniotic bands in the womb, restricting blood flow to the affected portion of the fetes. It normally affects legs, arms, toes and fingers. In utero surgery may be performed to rectify the condition if there is risk of amputation of the limb after the birth.
Twin-to-twin transfusion syndrome (TTTS): TTTS is a condition that occurs in identical twins wherein unbalanced exchange of blood takes place between the twins. One receives higher amount of blood whereas the other receives less amount. The fetus with less blood supply may become anemic and the one with excess blood supply may suffer heart failure due to excess fluid. Fetal surgery through laser fetal intervention is the preferred option to correct the condition. This procedure involves inserting a laser along with small telescope into the uterus and separating the blood vessels on the placenta that are connected to both twins.
Congenital high airway obstruction syndrome (CHAOS): Congenital high airway obstruction syndrome (CHAOS) refers to the blocking of fetal airway resulting in enlarged lungs, windpipe and bronchial tube. A complete or near to complete blockage may lead to a heart failure. Though congenital high airway obstruction syndrome (CHAOS) is treated after birth, in severe cases where fetes is at high risk such as hydrops, fetal surgery is performed.
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Bibliography / Reference
Collection of Pages - Last revised Date: September 25, 2020