Commentary and Review by:
Julia Ann Drose, BA, RDMS, RDCS
OBGYN.net Ultrasound Advisory Board Member
Title: Limb amputation in amniotic band syndrome: serial ultrasonographic and Doppler observations.
Reference: Ultrasound Obstet Gynecol 1997; 10:312-315
Authors: OP Tadmor, GA Kreisberg, R Achiron, S Porat and S Yagel
Institution: Department of Obstetrics and Gynecology, Misgav Ladach General Hospital, PO box 90, Jerusalem 91000,27, Hizkiyahu hamelech St., Jerusalem 93190, Israel.
Study Design: Case ReportAbstract:
A case report describing the serial ultrasound documentation of natural limb amputation in a fetus with amniotic band syndrome. The fetus first presented at 21 weeks gestation with bilateral lower limb edema. A constriction ring was seen around both legs. Color Doppler documented arterial flow in both legs beneath the constriction rings. Subsequent sonograms at 24 and 28 weeks gestation showed decreased flow in the left leg and an absence of flow in the right leg. The gradual bending, breaking and resorption of the tibia and fibula of the right leg was serially documented. Birth at 38 weeks gestation revealed a male infant with amputation of the right leg below the knee and partial amputation of the left leg below the knee. Pathological examination of the placenta and amnion was normal.
Title: In utero lysis of amniotic bands.
Reference: Ultrasound Obstet Gynecol 1997; 10:316-320
Authors: RA Quintero, WJ Morales, J Phillips, CS Kalter and JL Angel
Institution: Florida Institute for Fetal Diagnosis and Therapy, St. Joseph's Women's Hospital, 13601 Bruce B. Downs Boulevard, Suite 160, Tampa, Florida
Study Design: Case ReportAbstract:
Two cases of prenatal surgical intervention to treat constricting amniotic bands are reported. The first case describes a fetus with amniotic bands attached to the face and left arm. Endoscopic scissors under ultrasound guidance were used to snip the band constricting the left arm. A follow up ultrasound, 6 days later showed resolution of skin edema. Previously seen ulnar deviation and abnormal flexion of the hand appeared to improve on subsequent ultrasound exams. Microphthalmia of the right eye , thought to be a result of attachment of the band to the face at 22 weeks, was also seen on follow up exam. Delivery at 39 weeks revealed only minimal scarring posteriorly on the left arm. The hand had evidence of radial paresis and mild hypoplasia. Facial defects included right microphthalmia, a small defect in the lower left eyelid and a remnant of tissue in the inner portion of the orbit. The second case utilized an endoscope with a contact YAG-laser fiber, to release a constricting band around the left ankle of a 23 week gestation fetus. The laser was able to release approximately 85% of the band. Complete release could not be accomplished without risking injury to the ankle. Follow up ultrasound revealed resolution of ankle edema and normal growth. The patient delivered spontaneously at 34.5 weeks following premature rupture of membranes. The baby underwent successful repair of the amniotic band with Z-plasties.
Title: Opinion: Amniotic bands.Ref: Ultrasound Obstet Gynecol 1997; 10:307-308
Author: MI Evans
Institution: Division of Reproductive Genetics, Wayne State University, Hutzel Hospital, Detroit, Michigan
Title: Opinion: Do amniotic bands amputate fetal organs?
Ref: Ultrasound Obstet Gynecol 1997; 10:309-311
Authors: M Bronshtein, EZ Zimmer
Institution: Department of Obstetrics and Gynecology, Rambam Medical Center, Haifa, Israel.Commentary:
This series of case reports and opinions present an interesting review of the etiology and sequlae of amniotic bands.
Tadmore and colleagues provide a unique opportunity to follow the natural history of in-utero limb amputations secondary to a constricting ring. The serial ultrasound findings of severe leg edema, cessation of blood flow to the extremity and subsequent autoamputation of the limb, chronicles the progressive and dramatic nature of this syndrome. The authors attribute the constriction ring to amniotic band syndrome, as opposed to a teratogenic or genetic insult, because of the asymmetry of the amputation. However, they also state that pathological examination of the placenta and amnion was normal. The companion paper by Quintero and associates offers the first report of in-utero surgery performed to release these constricting bands. This paper provides another example of the successful combination of ultrasound and endoscopic imaging to provide in-utero fetal therapy. In utero surgery was attempted in the first case at 22 weeks gestation. Following endoscopic localization of the constriction of the left upper extremity, a second trocar was inserted to allow the use of scissors under endoscopic guidance. However, bleeding from the uterine wall necessitated its removal. Ultimately, ultrasound guidance was used to guide the scissors to the constricting band and snip it.
A second surgical port was also attempted in the second case, but once again bleeding ensued, requiring it to be withdrawn. Ultrasound guidance of the scissors also proved ineffective secondary to angulation problems. Ultimately, a YAG-laser fiber was used which weakened the band, but was not utilized to completely release the band for fear of injury to the limb. This patient underwent successful repair of the band with Z-plasties following delivery. Together, these papers offer the reader both sides of the spectrum. Conservative observation of a case, as presented by Dr. Tadmore, which resulted in limb amputation, versus in-utero therapy provided by Dr. Quintero, preserving the fetal limbs. Also of interest are the two opinions included in this journal. Both opinions, the first offered by Dr. M.I. Evans, and the second by M. Bronshtein and E.Z. Zimmer, praise both papers as being landmark to the field of high-risk obstetrics. However, they once again raise the controversy that continues to surround the pathophysiology of limb constrictions associated with amniotic bands. In 1965, Torbin and colleagues presented the theory that amniotic band syndrome was the result of rupture of the amniotic membrane and its detachment from the chorion. They concluded that the exposed outer surface of the amnion produced mesodermic fibrous strings that attached and entangled fetal organs, leading to constriction and amputation anomalies. In Dr. Evans opinion, the case reported by Tadmore and colleagues would support this hypothesis. Bronshtein and Zimmer however, disagree with Torbin's theory. They agree that constriction rings may lead to limb amputation. They disagree, however, that these rings are formed by ruptured amnion. Their opinion supports that presented by Streeter in 1930, that constriction rings are the result of embryonic and/or teratogenic factors. They provided several interesting questions to support their position. Specifically:
- Why do amniotic bands attach or encircle a fetal organ, rather than coiling themselves along it?
- Why do amputations always occur transversely?
- What causes the amnion to stick to the fetal organ, and tighten itself around it, instead of stretching and tearing?
- How does an amniotic band cause anomalies such as encephalocele, cleft lip, microphthalmia or club foot?
In conclusion, the two papers and two opinions provided in this issue of Ultrasound in Obstetrics and Gynecology, provide an in depth look at the etiology, progression and in-utero therapy of constricting bands. They provoke the reader to revisit and perhaps rethink long held theories regarding this abnormality.