A 35 year old Caucasian primigravid woman had a medical history of multiple sclerosis, hypothyroidism and a gynaecological history of fibroidectomy. Premature rupture of amniotic membranes occurred at 33 weeks of gestation. During labour, one week later, prolonged fetal decelerations were noted and a fetal scalp blood pH was 7.09. Delivery was effected by means of ventouse extraction.
The male infant weighing 1925 g was born in poor condition with the cord round his neck. Bag and mask resuscitation was begun. Apgar scores were 6 at one minute, 9 at five minutes and ten at 10 minutes. Intramuscular vitamin K (1 mg) was administered. Within 24 hours the baby was noted to have a large cephal-haematoma over the frontal region and anterior fontanelle. Haemoglobin remained stable but jaundice developed and responded to phototherapy.
The baby was transferred to our institution on day four. From two to eight weeks the frontal prominence gradually increased in size and became transilluminable (Fig. 1). Regular ultrasound examinations of the head were performed and on day 20 an area of cystic change in the frontal region was noted. Magnetic resonance imaging confirmed the presence of the large cephalhaematoma and an extra-axial cystic lesion in the frontal region consistent with porencephalic change (Fig. 2). In addition, an extra-cranial leptomeningeal cyst was found overlying the anterior fontanelle deep to the cephalhaematoma. Colour Doppler delineation of the blood flow within the extracranial membrane confirmed communication with the intra-cranial component.
Surgical exploration was undertaken at eight weeks of age via a bicoronal incision. The cephalhaematoma had been replaced by a straw-coloured fluid, presumably transudative across the semipermeable arachnoid lining (Figs. 3 and 4). The expanded pericranial capsule of the collection was used to repair the dural defect in layers (Fig. 5). Post-operatively the baby made an uneventful recovery with no evidence of recurrence after three months.
Following the editorial by Chalmers and Chalmers1 in 1989 ventouse vacuum extraction has gained increased popularity as the first line method of operative vaginal delivery. The main rational for this is a significant reduction in maternal morbidity. There are significant advantages of vacuum extraction over forceps in terms of avoiding caesarean section, minimising maternal anaesthetic requirements and reducing maternal trauma2.
Objective evidence for and against vacuum extraction in terms of neonatal outcome is less clear. Silicone vacuum extractor cups appear to be safer than the metal cups in reducing the incidence of significant scalp trauma3. Nevertheless, vacuum extraction is more likely than forceps to result in cephalhaematoma, retinal haemorrhage and low five minute Apgar scores2. The obstetric community remains concerned about the possibility of more serious craniofacial trauma resulting from ventouse extraction2,4,5.
In this case vacuum extraction was used to assist in delivering a preterm infant in a primigravid woman. From the position of the cephalhaematoma it would appear that the cup was placed directly over the anterior fontanelle. As has previously described, it is likely that the negative pressure induced by the ventouse and traction resulted in a dural tear at the anterior fontanelle6–10. We postulate that the lining of the resultant leptomeningocoele acted as a semi-permeable membrane for transudation of cerebrospinal fluid into the resolving cephalhaematoma thus precluding a diminution in size.
Routine ultrasound scanning gave the first indication that the cephalhaematoma in this case was associated with a leptomeningocoele. Magnetic resonance imaging was valuable in delineating the anatomy. Ultimately, as previously described, colour Doppler ultrasound confirmed the diagnosis by delineating influence of blood flow between the cyst membrane and intracranial meninges7.
The leptomeningocoele was successfully managed by surgical intervention in a specialised craniofacial environment. Repair of the hernial defect was facilitated by use of the expanded pericranium which formed a capsule around the haematoma.