Complete sternal cleft - A rare congenital malformation and its repair in a 3-month-old boy: A case report.

Complete midline sternal cleft is a rare congenital anomaly resulting from failed midline ventral fusion of the sternal bars. Very few cases of complete sternal cleft have been described in literature. We present a case of complete sternal cleft in a 3-month-old child. The patient underwent primary closure of the defect using stainless steel wires.

INTRODUCTION

Congenital sternal cleft is a rare developmental anomaly. Only 23 cases have been reported in literature.[1] The first case of sternal cleft was reported in 1743.[2] It may occur as part of a defined syndrome, e.g., Cantrell's pentalogy. Sternal cleft may be partial or complete. Isolated sternal cleft without any associated anomaly is rare. Surgery is indicated to protect the heart and mediastinal structures. Our objective is to present a case of primary surgical repair of complete sternal cleft in a 3-month-old child. Relevant literature review has been discussed.

CASE REPORT

A 3-month-old male child was referred to us with history of repeated respiratory tract infections. On physical examination, the baby had midline chest defect in form of complete absence of sternum. The defect measured 7 cm × 4 cm in maximum vertical and horizontal dimensions. The defect was covered with thin skin. Cardiac pulsations were visible in the defect. A vertical midline raphe extended from umbilicus to lower edge of cleft. The child had a hemangioma over the lower lip and another over the right parotid region. These hemangiomas were present since birth and were gradually increasing in size. The baby had respiratory tract infection. Abdominal examination was normal.

Chest x-ray showed that the body of sternum had not ossified and the medial ends of sternum were far away from midline. The lung fields were clear.

2-D echo was normal.

Computed tomography scan of thorax showed complete sternal agenesis with depression in central part of anterior chest wall. Medial ends of the clavicles were widely separated with small bony fragments articulating with them. There was subpleural and peribronchovascular consolidation in basal segment of right lower lobe.

Ultra sonography (USG) skull and USG abdomen were normal.

The patient was optimized preoperatively and upper respiratory tract infection was brought under control.

The patient underwent operative procedure as follows:

A “U”-shaped mark was made on the chest wall as shown in Figure 1 and skin flap was raised carefully separating it from the pericardium. Sternal bars were dissected free of overlying muscle and underlying pericardium and pleura. Four stay sutures were taken with stainless steel wire hooking the two sternal bars. The sternal bars were approximated by pulling together the untied sutures and patient's vital parameters such as pulse rate, blood pressure, oxygen saturation in both upper and lower limbs, and electrocardiogram were monitored for 10 min. After confirming stable vital parameters the wire suture were tightened, twisted, and buried in the sternal bars. The excess skin flap was excised. Subcutaneous tissue was closed with vicryl 3-0, and skin incision was closed using prolene 4-0 in a subcuticular fashion. Postop period was uneventful and the appearance was satisfactory. The patient is on a 3-monthly follow-up with no complaints [Figure 2]. His lower lip and right parotid hemangiomas are being managed on outpatient basis.

Figure 1

A “U”-shaped flap taken to expose sternal cleft and four stainless steel sutures taken

Figure 2

Follow-up at 3 months

DISCUSSION

The sternum is formed by the medial migration of cells from two bands of lateral plate mesoderm present on either side of the developing chest wall. This process is completed by the 10th week of intrauterine life.[3] A sternal cleft usually results if this fusion does not take place by the 8th week of gestation. A few causes such as methylcobalamin deficiency, alcohol abuse during pregnancy, and a disruption in HOX-B4 gene have been postulated in murine models.[4] Fisher, in 1879, reported an association of cervicofacial hemangiomas with sternal cleft. Recently, the acronym “PHACE” has been proposed to describe the association of posterior fossa malformations, hemangiomas, arterial anomalies, coarctation of the aorta, eye abnormalities, and sternal nonunion.[5] Usually these defects are asymptomatic and have a female preponderance. Rare association with other malformations such as gastroschisis, VACTERL syndrome, Dandy–Walker syndrome, pectus excavatum, and chest-wall hamartoma have also been described.

Maier and Burten[6] achieved the first primary closure of sternal cleft in 1943 in an 11-week-old infant and stressed the importance of early repair in infancy, when the chest is most flexible. Marcello et al. are credited with repairs done at earliest age of 14 and 28 days of life in two patients. In infancy direct approximation of the sternum is achieved after converting a partial cleft to a complete one by removing a sagittal wedge from the lower part of sternum, creating fresh edges and preserving the xiphoid.[78] Even though the condition is frequently diagnosed at birth, patients may present with this condition even in adolescence. The general consensus about the timing of sternal cleft repair is in the neonatal period using autologous tissue as the flexibility of the thorax is maximum at this age leading to minimal compression on the underlying structures.

Sabiston[9] in 1958 devised the use of multiple bilateral sliding chondrotomies. This reduced the internal organ compression in older patients. Several other techniques were subsequently developed such as periosteal flaps, cartilage, and muscle mobilizations. The use of synthetic materials such as Marlex, Teflon, Prolene mesh, meth-acrylate sandwich, and autogenous tissues such as iliac crest and rib grafts covered with pectoralis major myocutaneous flaps has also been reported. The major hazard of complex sternal reconstruction is due to the foreign material causing untoward reaction, recurrent infection, extra weight on the sternum, and the difficulty encountered during re-exploration and approach for cardiac surgery. A technique of “posterior periosteal flap from sternal bars and chondral graft” has been proposed by Jose´-Ribas Milanez de Campos et al.[10] as an option with good aesthetic and long-term functional results. In patients with insufficient sternal bone a fixation system using metallic plates is ideal. This technique was proved to be useful in cases of complicated sternal dehiscence and mediastinitis. One added advantage of this system is its locking and unlocking feature that allows for easy re-exploration.

We conclude that early repair of cleft sternum is feasible and offers good functional and cosmetic results.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.