Amniotic Band Syndrome

Key Points:

  • Combination of highly variable internal and external defects and malformations, associated with constriction rings
  • Heterogeneous etiology without specific heritability pattern
  • Surgical release and reconstruction are the mainstays of treatment
  • Goals of treatment are to avoid limb ischemia and subsequent long-term sequelae, and maximize patient function

Description:

Although known under many different names, amniotic band syndrome (ABS) or constriction band syndrome includes a broad grouping of congenital anomalies associated with constriction rings and amputations of limbs and digits along with central abnormalities that do not occur along known lines of embryonic development (Koskimies, 2015).  in 1832 (Goldfarb, 2009). The pathogenesis is largely believed to be heterogeneous with varied clinical presentation and familial heritability is rarely reported. The most common peripheral abnormalities are amputations of limbs or digits, constriction rings, and acrosyndactyly (Goldfarb, 2009).

Epidemiology:

Although one study found the prevalence to be as high as 8.3 per 10,000 births when miscarriages, stillbirths, and newborns were all included, other studies of just stillbirths or stillbirths and newborns have found the prevalence to be much lower, ranging from 0.55-0.9 per 10,000 (Cignini, 2012; Kawamura, 2009; Koskimies, 2015). 

Clinical Findings:

Limb or digit amputations, constriction rings, and acrosyndactyly are the most common abnormalities in amniotic band syndrome (Goldfarb, 2009). Scoliosis, clubfeet, leg length discrepancies, craniofacial abnormalities, body-wall defects, and other visceral abnormalities are also seen but are less common. The clinical manifestations are typically grouped into classic and non-classic categories. Classic findings are disruptions or deformations including amputations, constriction rings, amputation defects, and clubfoot. Non-classic defects are from malformation and include cleft lip or palate, body wall defects, and imperforate anus (Goldfarb, 2009; Kawamura, 2009). Distal limb deformities include syndactyly, acrosyndactyly, phalangeal hypoplasia, and amputation. 

The Patterson classification system is often used to describe clinical manifestations of amniotic band syndrome. Category 1 includes simple constriction rings. Category 2 involves rings with associated deformity of the distal part that may or may not include lymphedema. Category 3 involves the rings with acrosyndactyly and is further broken up into three types based on extent of web formation between fingers. Category 4 includes patients with intrauterine amputation due to the extent of the constriction (Kawamura, 2009).

Imaging Studies:

The mainstay of imaging evaluation is the prenatal ultrasound, and this is the basis of diagnosis as well. On ultrasound, defects can be seen as large structural abnormalities or constriction bands may interfere with a fetus’ typical movements.  ABS is usually diagnosed at the end of the first trimester or beginning of second trimester. If fetal surgery is being considered or ultrasound findings are not definitive, magnetic resonance imaging may be used to further evaluate the bands and any secondary deformities (Barros, 2013). 

Etiology:

There are three main theories behind the formation and development of ABS. No single theory can fully explain all the clinical findings; therefore, the current thought is that multiple factors likely play a role (Goldfarb, 2009). The intrinsic theory, described by Streeter in 1930, states a germline pathology is the basis for ABS, potentially explaining why central defects such as craniofacial abnormalities, body wall defects, and internal organ abnormalities are seen (Streeter, 1930). However, this explanation does not as easily apply to peripheral constrictions. The extrinsic theory, proposed by Torpin in 1965, states rupture of the amniotic sac leads to formation of amniochorionic mesodermal bands, which may become wrapped around various fetal parts resulting in constriction bands. The gestational age at which the amniotic sac rupture occurs determines the overall extent of the band deformities (Torpin, 1956). The amniotic bands are fibrous and may include fibroblasts and squamous cells.  The do not contain elastic tissue, and upon encircling part of the fetus can result in a ligature effect (Kim, 2007; Goldfarb, 2009). Finally, the vascular theory, offered by Van Allen in 1981, argues that vascular disruption caused by a traumatic event (e.g. amniotic rupture, direct trauma, teratogen exposure, etc.) can explain the constellation of both internal and external defects seen in these patients (Van Allen, 1981).

Outside of these general theories, several factors have been found to correlate with increased risk for ABS. These factors include acute illness, medication drug use (particularly misoprostol), tobacco use, illicit drugs, maternal diabetes, and iatrogenic damage to the amniotic membrane (Cignini, 2012). 

Treatment:

Treatment options are almost all surgical in nature, ranging from limb-sparing release of bands to cosmetic repair. Typically, if a band is superficial it is simply observed unless it impedes venous or lymphatic drainage and becomes symptomatic. Deep bands carry an increased risk of vascular disruption and potential limb-threatening constriction. These are treated surgically with circumferential Z-plasty or W-plasty (Kawamura, 2009). Surgical reconstruction may also be pursued for patients with syndactyly, acrosyndactyly, or digital hypoplasia in order to improve function. Severe bands can be treated as soon as a few days after birth, while others can be addressed on an elective basis if ischemia of the limb is not a concern. Many surgeons prefer to do a two-stage band release technique to help preserve distal vascular flow with a 6-12 week interval. For acrosyndactyly, surgery is recommended at six months to one year of age to allow for the best longitudinal growth possible (Kawamura, 2009). Following surgical treatment or in patients with limb defects, prosthesis fitting and intense physical therapy are vital to provide the child with the most function possible (Barros, 2013). 

Complications:

Most severe complications result from untreated, severe constrictions that result in limb ischemia, necrosis, and eventual osteomyelitis necessitating a more significant amputation. With surgical treatment, there can be disruption of the vascular and lymphatic flow to the distal segment, which is why many surgeons prefer to treat these in a staged manner as described above (Kawamura, 2009). Along with the deformities, many patients with this condition unfortunately are miscarried, or are born preterm or at low birth weight (Barros, 2013). However, depending on the extent of the disease, many patients are able to live full lives and achieve great success. One such patient, Shaquem Griffin, played football as a linebacker for University of South Florida and not only received an invite to the NFL scouting combine but also was named the 2016 American Athletic Conference Defensive Player of the year. He accomplished all of this with only one hand as his left hand was amputated at the age of 4 years from ABS complications (Goodbread, 2018).

References:

  1. Barros M, Gorgal G, Machado AP, Ramalho C, Matias A, Montenegro N. Revisiting Amniotic Band Sequence: A Wide Spectrum of Manifestations. Fetal Diagn Ther. 2014; 35: 51-6. 
  2. Cignini P, Giorlandino C, Padula F, Dugo N, Cafa EV, Spata A. Epidemiology and risk factors of amniotic band syndrome, or ADAM sequence. J Prenatal Med. 2012 Oct; 6(4): 59-63. 
  3. Goldfarb CA, Sathienkijkanchai A, and Robin NH. Amniotic Constriction Band: A Multidisciplinary Assessment of Etiology and Clinical Presentation. J Bone Joint Surg Am. 2009; 91(Suppl 4): 68-75. 
  4. Goodbread, C. One-handed LB Shaquem Griffin on verge of making NFL history. NFL.com. 2018. http://www.nfl.com/news/story/0ap3000000909332/article/ onehanded-lb-shaquem-griffin-on-verge-of-making-nfl-history. Published January 2018. Accessed February 2018. 
  5. Kawamura K, Chung KC. Constriction Band Syndrome. Hand Clin. 2009 May; 25(2): 257-64.
  6. Kim JB, Berry MG, Watson JS. Abdominal constriction band: A rare location for amniotic band syndrome. J Plast Reconstr Aesthet Surg.  2007; 60(11): 1241-3. 
  7. Koskimies E, Syvänen J, Nietosvaara Y, Mäkitie O, and Pakkasjärvi N. Congenital constriction band syndrome with limb defects. J Pediatr Orthop. 2015 Jan; 35(1): 100-3. 
  8. Streeter G. Focal deficiencies in fetal tissues and their relation to intrauterine amputations. Contrib Embryol Carnegie Inst. 1930; 22: 1-46.
  9. Torpin R. Amniochorionic mesoblastic fibrous strings and amniotic bands: associated constricting fetal malformations or fetal death. Am J Obstet Gynecol. 1965 Jan 1; 91: 65-75. 
  10. Van Allen, MI. Fetal vascular disruptions: mechanisms and some resulting birth defects. Pediatr Ann. 1981; 10: 219-33. 

Top Contributors:

David Knowles MD
Karen Bovid MD