Fellow Pediatric Anesthesia Chief of Department Dept. of Pediatric Anesthesia BJ Wadia Hospital for Children Mumbai Maharashtra Address for correspondence Dr Sudivya Sharma Flat No. 77 B Wing Mahavir Krupa Building TJ Road Sewri W Mumbai 400 015 Maharashtra E mail drsudivyasharma gmail.com ABSTRACT Constriction band syndrome CBS or amniotic band syndrome is a group of congenital birth defects believed to be caused by entrapment of fetal parts usually a limb or digits in fibrous amniotic bands while in utero. The commonly accepted view is the extrinsic theory that CBS occurs when the inner membrane amnion ruptures without injury to the outer membrane chorion . The chorionic side of the amnion emanates numerous mesoblastic fibrous strings which entrap and catch the fetal parts. On the other hand the intrinsic theory proposed by George Streeter explains the ring constrictions as areas of defectively formed tissue due to defective germ plasma areas and due to the closeness to the amnion caused its connection. CBS not only causes esthetic deformity in the affected limb but may also cause vascular compromise which can lead to lymphedema and or amputation. Concerning the treatment of congenital CBS the use of Z plasty or W plasty after the excision of the constriction band in a one or two stage approach is recommended. Keywords Constriction band syndrome mesoblastic fibrous strings defective germ plasma areas lymphedema amputation Constriction band syndrome CBS or amniotic band syndrome is a group of congenital birth defects believed to be caused by entrapment of fetal parts usually a limb or digits in fibrous amniotic bands while in utero. Other names include amniotic band syndrome also known as Adam Complex Streeter s dysplasia annular groove ring constriction syndrome and pseudoainhum. It has an incidence of one in 1 200 to one in 15 000 live births and affects both sexes at a ratio of 1 1. There is a significant predilection for the upper extremities and an increased frequency in distal limbs and longer digits are significantly more involved than shorter ones.1 6 THEORIES The commonly accepted view is the extrinsic theory that CBS occurs when the inner membrane amnion ruptures without injury to the outer membrane chorion . The chorionic side of the amnion emanates numerous mesoblastic fibrous strings which entrap and catch the fetal parts. This extrinsic theory was proposed by Richard Torpin an obstetrician in 1965.7 In some cases complete natural amputation of a digit s or limb may occur before birth or the digit s or limbs may be necrotic dead and require surgical amputation following birth. There is an intrinsic theory proposed by George Streeter the director of embryology at Carnegie Institute in 1930 which is called Streeter s dysplasia . He explained the ring constrictions as areas of defectively formed tissue due to defective germ plasma areas and due to the closeness to the amnion caused its connection. This theory is supported by evidence of cases in which the infant affected is born with the amnion intact.8 PRESENTATION The variable clinical manifestations of congenital CBS can best be explained as the response of the growing embryologically defined limb to intrauterine deformation or band induced compression and ischemia. In the hand digital amputations are most common in the index middle and ring fingers Figs. 1 and 2 whereas in the foot amputations of the hallux are most often noted. Band indentations are often present at multiple levels. Proximal bands may be associated with neural compression. There are several features that are relatively consistent Syndactyly Distal ring constrictions Deformity of the nails Stunted growth of the small bones in the digits Limb length discrepancy Distal lymphedema Congenital band indentations If a band wraps tightly around a limb the limb can actually be completely amputated. A strong relationship between CBS and clubfoot exists. In 1961 Patterson used a classification that is still widely used today.4 The classifications are as follows Simple ring constrictions Ring constrictions accompanied by deformity of the distal part with or without lymphedema Ring constrictions accompanied by fusion of distal parts ranging from mild to severe acrosyndactyly Intrauterine amputations. MANAGEMENT CBS not only causes esthetic deformity in the affected limb but may also cause vascular compromise which can lead to lymphedema and or amputation. The treatment of CBS is therefore aimed at improvement of function and improvement of cosmetic appearance. Concerning the treatment of congenital CBS most references recommend the use of Z plasty or W plasty after the excision of the constriction band in a one or two stage approach.9 Very rarely if CBS is detected in utero fetal surgery may be performed to save a limb or other deformity. CONCLUSION The future for those suffering from CBS is continually improving because of upcoming in utero surgical procedures. Regardless what theory proves to be evident in causing CBS it is extremely important to seek prenatal medical attention when pregnant. It is likely that genetic predisposing factors are involved as can be inferred by the higher incidence of the syndrome in first degree relatives of the affected individuals. No less important however appear to be acquired yearly factors such as the use of drugs tobacco diabetes known for their action on the vascular system or even iatrogenic factors like the sting from amniocentesis which are an insult to the amniotic membranes. REFERENCES 1. Foulkes GD Reinker K. Congenital constriction band syndrome a seventy year experience. J Pediatr Orthop. 1994 14 2 242 8. 2. Al Qattan MM. Classification of the pattern of intrauterine amputations of the upper limb in constriction ring syndrome. Ann Plast Surg. 2000 44 6 626 32. 3. Garza A Cordero JF Mulinare J. Epidemiology of the early amnion rupture spectrum of defects. Am J Dis Child. 1988 142 5 541 4. 4. Patterson TJ. Congenital ring constrictions. Br J Plast Surg. 1961 14 1 31 5. Kino Y. Clinical and experimental studies of the congenital constriction band syndrome with an emphasis on its etiology. J Bone Joint Surg Am. 1975 57 5 636 43. 6. Flatt AE. The Care of Congenital Hand Anomalies. St Louis CV Mosby Company 1977. 7. Torpin R. Amniochorionic mesoblastic fibrous rings and amniotic bands associated constricting fetal malformations or fetal death. Am J Obstet Gynecol. 1965 91 65 75. 8. Streeter GL. Focal deficiencies in fetal tissues and their relation to intrauterine amputations. Contrib Embryol Carnegie Inst. 1930 22 1 44. 9. Wiedrich TA. Congenital constriction band syndrome. Hand Clin. 1998 14 1 29 38.