Amniotic constriction band of the pelvis in a newborn male

Abstract

We present the case of a newborn male with congenital amniotic band syndrome and a constriction band involving the right inguinal crease, scrotum and perineum. He was diagnosed prenatally and referred to our institution after developing a right femoral nerve palsy. Surgical management included excision of the constriction band and Z-plasty closure. We discuss the considerations for safe and cosmetic surgical outcomes in this rare presentation of amniotic band syndrome. A multidisciplinary approach to management is essential during workup and surgical intervention.

1 Introduction

Amniotic band syndrome (ABS) is a congenital condition consisting of in utero entrapment of fetal structures within fibrous amniotic constriction bands. The incidence has been reported between 1 in 1200 and 1 in 15,000 live births. ABS affects limbs or digits in 80 % of cases and there are several theories regarding how constriction bands form. Constriction bands around the thorax, abdomen and pelvis are rare. Based on the classification system proposed by Graham et al., there has been one other case report of pelvic constriction bands presented in the literature. To our knowledge, this is the first case report of a male patient with a pelvic constriction band involving the groin, scrotum and perineum.

2 Case presentation

A male infant was referred to our institution at one month of age for evaluation of amniotic band syndrome with a constricting pelvic band. The constriction band was first identified on prenatal ultrasound at 10 weeks and was monitored until birth via spontaneous vaginal delivery at 38 weeks gestation. Subsequently he was noted to have decreased ability to extend his right leg at the knee. He otherwise had normal bowel and bladder function. On physical examination there was a constriction band encircling his right anterior proximal thigh, right inguinal crease, right hemiscrotum, perineum, left buttock and lower back ( Fig. 1 ). In addition, his right great toe was absent and there was a constriction band on the right second toe. Given his physical exam findings and concern for possible femoral nerve compression, electromyography and MRI were completed. These demonstrated a right femoral neuropathy with denervation and atrophy of the right rectus femoris muscle. A multidisciplinary discussion was held with the surgical teams involved to determine next steps. Indications for surgical excision of the constriction band included right femoral neuropathy and displacement of right testicle in the upper portion of the scrotum as well as to assure function of underlying structures and cosmesis.

At 6-weeks-old he underwent his first surgical procedure including excision and release of constriction bands of the right inguinal crease, femoral nerve evaluation ( Fig. 2 a) and multiple Z-plasty closure. An incision was made over the constriction band extending from the right flank down to the lateral aspect of the right hemiscrotum. The dissection was carried down to the deep muscular fascia and the band was elevated off of the underlying fascia. The right femoral nerve was identified and found to be compressed initially; however, following band release the nerve appeared grossly normal. Next, approximately five Z-plasties were completed along the length of the incision for closure. Scarpa’s fascia was inset with 0-Vicryl. Deep dermis and skin were closed with 4–0 Monocryl. Skin was reinforced with horizontal mattress sutures using 5-0 Vicryl Rapide. He recovered well and continued physical therapy.

He returned to the operating room at 5-months-old for his second stage procedure to address the remaining constriction band and right testicle. He was initially positioned supine, frog leg position. A urethral feeding tube was placed to assist with identification of the urethra during perineal dissection. The dissection was started at the right inguinal crease extending to the scrotum and anterior perineum ( Fig. 2 b). The right testicle and cord were identified and isolated to prevent injury. A rectal exam was performed, and a Hegar dilator was used during the dissection to define the rectal wall as the rectum and anus were not midline and did not follow a typical anatomical course. The deepest aspect of dissection was in close proximity to the rectal wall and bulbar urethra at certain points. A Z-plasty was used to close the anterior side of the dissection, including the scrotum ( Fig. 2 c). The right testicle was palpable in the dependent portion of the right hemiscrotum which was not previously possible due to the constriction band separating the inferior and superior aspects of the scrotum.

Next, the patient was repositioned prone, and the posterior aspect of the constriction band was resected and Z-plasty completed. The flaps were transposed and then inset using 3-0 Vicryl in Scarpa’s fascia, 3-0 Vicryl in deep dermis and 4-0 Monocryl running intracuticular. He was admitted for overnight observation and discharged on post-operative day 1. He recovered without complications. At 9-months-old his incisions were healing well ( Fig. 3 ), the right testicle was palpable in the dependent portion of the right hemiscrotum, and he was pulling to stand and starting to walk.