Sternal cleft: Anaesthetic management of a rare congenital anomaly.

Sir,

A sternal cleft is a rare congenital anomaly resulting from the failure of fusion of lateral sternal bars during the 3rd month of intrauterine development.[1] It may be complete or incomplete (bifid type), depending on the degree of fusion of two lateral sternal bars, the latter being more common.[23] Associated anomalies, particularly cardiac anomalies, result in poor outcomes.[45] The surgical procedure is associated with critical changes in haemodynamics and cardiopulmonary mechanics, necessitating invasive monitoring, preparedness for cardiopulmonary bypass and resuscitation (CPR).[6] Here, we report anaesthetic management of a case of sternal cleft repair with a brief review of available literature.

A full-term male baby, weighing 2.6 kg, was delivered by caesarean section. The attending paediatrician noted a longitudinal depression at the sternal region which was more evident during inspiration [Figure 1]. Pulsation of great vessels was easily seen through the defect which was covered by a thin layer of skin. Two parallel and completely separated sternal bars were palpated along the depression. There was no anterior abdominal wall defect, diastasis of recti, fascial haemangioma, atrophic skin or paradoxical movement of the thoracic cage. A provisional diagnosis of isolated sternal cleft was made, and the baby was evaluated for associated anomalies. Chest X-ray revealed normal lung fields with a wide gap between the medial ends of the clavicles [Figure 2]. Echocardiogram and blood investigations were normal. The child was posted for sternal cleft repair on the 3rd postpartum day. In the operating room, standard monitoring was attached. The pulse rate was 130/min, oxygen saturation 97% with oxygen (O2) supplementation by nasal cannula at 3L/min and respiratory rate was 34/min. The child was induced with inhalation of sevoflurane (2 to 8%) in O2 and two peripheral intravenous lines were secured. The injections of fentanyl (5μg) and atracurium (1.5mg) were administered, and trachea was intubated with 3.5mm uncuffed endotracheal tube. The right radial artery was cannulated for invasive blood pressure monitoring. Anaesthesia was maintained with isoflurane in O2 /air (40–60) mixture. The child was put on pressure controlled ventilation, and adequate tidal volume (VT) was achieved with peak inspiratory pressures (PIP) of 18 mmHg. A vertical midline incision from the suprasternal notch to xiphoid process was given by the surgeons, and margins of sternal bars were freshened, followed by closure of the defect. The blood loss was minimal. PIP and haemodynamics were observed for next 10 min before knotting the sutures. PIP of 20 mmHg was required to achieve the same VT with no significant changes in haemodynamics. On the 2nd postoperative day, the trachea was extubated, and the child was discharged home in stable condition on the 7th day.

Figure 1

Obvious midline depression in the child

Figure 2

Wide gap between the medial ends of the clavicles

The reported incidence of sternal cleft varies across the institutes. Acastello et al.[7] noted an incidence of 0.15% of all chest deformities during a 25 years period observation. It is usually diagnosed at birth due to the presence of cosmetic deformity and is generally asymptomatic. Associated cardiac anomalies, defects in the anterior chest wall (ectopia cordis), or the presence of Cantrell's Pentalogy (defects involving the abdominal wall, sternum, diaphragm, pericardium and heart) indicate poor prognosis.[45]

Surgical correction is required to restore bony protection to the vital organs and great blood vessels, to provide normal intra-thoracic pressure-volume relationships and to eliminate paradoxical movement of the thoracic viscera.[123] Surgery is preferred in the new born period as the thoracic cage is more compliant, and the closure of the chest wall can easily accommodate the thoracic viscera without compressing the underlying structures.[6] It presents distinct challenges to the anaesthesiologist due to the potential involvement of multiple organ systems and the risk of direct injury to the vital organs. Associated complex congenital heart disease or poor baseline cardiac functions warrant standby cardiopulmonary bypass.[456] Arterial and central venous pressure monitoring is useful, as is trans-oesophageal echocardiography (TEE). Intraoperative TEE offers real-time information on volume status and cardiac output. The repair may lead to compression on the intra-thoracic organs which may cause haemodynamic instability and decreased lung compliance necessitating invasive monitoring, and close observation of ventilatory parameters. Rapid blood loss, arrhythmias, cardiac dysfunction and pneumothorax are the possible complications.[23] Literature advises test closure for 5–10 min while observing the haemodynamics and cardiopulmonary interactions.[3] To conclude, repair of sternal cleft requires invasive haemodynamic monitoring, close observation of ventilatory parameters and preparedness for CPR. Elective postoperative mechanical ventilation with adequate analgesia helps in early recovery.