Case presentation

Our patient is a 6 days old male baby, first in birth order and product of a non consanguineous marriage .The patient was born with congenitally abnormal right hand. On thorough examination, the patient has bilateral talipes equinovarus in addition to abnormal right hand. In the right hand, the thumb is normal, the index finger has amputated distal phalanx, the middle and the ring finger each has amputated distal phalanx and each bears a constriction ring at the level of middle phalanx and the little finger has amputated middle and distal phalanx. The patient has been attached to outpatients department for follow-up of hand defect .The worried parents were counseled and reassured that the disease has no proven familial link and that the abnormality in their first child does not increase the possibility of constriction/auto amputations in future offspring.

Figure 1

Figure 1: Constriction rings right hand (dorsal view)

Figure 2

Figure 2: Constriction ring Right hand (palmar view)

Discussion

Constriction ring syndrome is a rare congenital anomaly ₁₂ Incidence of this condition is around 0.01% .₃ Male and female patients in equal ratio and belonging to all ethnic groups are involved .₁₃Clinical presentations are varied from simple constriction rings to in-utero amputation or gangrene requiring amputation after birth. The part distal to the constriction may be normal or may be edematous (congenital lymph edema). Additional musculoskeletal disorders that may be present include talipes equinovarus, syndactyly, acrosyndactyly, hypoplastic nails, hypoplastic fingers, pseudoarthrosis of underlying bones, and absence of bones, peripheral nerve defects, cleft lip, cleft palate, umbilical hernia, microphthalmia, hydrocephalus, microphthalmia, thoracochisis and gastroschisis.₄

It is believed to occur due to partial rupture of amniotic sac. Only amnion is ruptured leaving chorion intact. The fibrous bands of the ruptured amnion float in the amniotic fluid which encircle and trap some part of fetus(extrinsic theory) leading to congenital abnormalities.₃ There are however some supporters of intrinsic theory who defend that the constriction ring represents a defect of the embryological development resulting from abnormal differentiation of the germinative plasma.₁₅

The constriction band can be superficial or deep. Superficial bands usually do not cause neurovascular damage or distal lymphedema and the medical attention is usually sought for cosmetic reasons. Deep bands , on the other hand, can result in neurovascular damage of variable intensity, requiring at times , urgent surgical intervention due to intensification of the progressive distal edema and vascular compromise.₄₆₇₈ Peripheral nerve suffer from from lesion (axontomesis, nerotmesis) at the level of constriction band and the nervous tissue ,proximal and distal to the band have been shown in literature to have normal at the microscopic level.₉ Early diagnosis of the congenital band is possible using ultrasound after the first trimester of pregnancy.₁₀

Treatment in the patients when surgical intervention is required includes Z-plasty, W-plasty or excision of the band with flap rotation of subcutaneous fat and closure of skin. The procedure can be carried out in a single stage ₁₁ as per some workers or as per other school of thought, half of the band is excised in first stage and rest in the second stage after an interval of six to twelve weeks.₅