Early Repair of Frontoethmoidal Encephaloceles Reverses Abnormal Frontal Bone Development

Objective Congenital frontoethmoidal encephaloceles are rare malformations whose surgical treatment remains challenging. In severe cases, they are associated with a shallow sloping forehead, thought to be secondary to abnormal development of frontal lobes and frontal bone. We report two cases of frontoethmoidal encephalocele repaired prior to the age of 4 months with autologous bone grafting of the cranial base defect, resulting in reversal of forehead sloping and normal frontal lobe and calvarial development, highlighting the importance of early repair.

Case Presentation Case 1 was born at 37 weeks’ gestation with a left nasal mass and respiratory distress requiring intubation. On exam, his head was microcephalic with a shallow sloping forehead. His left naris was enlarged with a 2 × 4 cm soft red membranous sac protruding. CT and MRI showed a nasoethmoidal encephalocele extending through the cribriform plate out the left nares. The skull base defect was 2.0 × 0.9 cm. Case 2 was born at 35 weeks’ gestation, with microcephaly, shallow sloping forehead, orbital hypertelorism, and a 3 × 3 cm skin covered mass protruding from the frontal area between the eyes, including the nasion. MRI and CT revealed a nasofrontal encephalocele protruding through a 1.5 × 2 cm cribriform plate defect. Both infants underwent (case 1 at 4 weeks; case 2 at 4 months) bifrontal craniotomy, excision of encephalocele, duraplasty, and repair of cribriform plate defect using a full-thickness autologous cranial bone graft harvested from the right parietal bone and secured with absorbable plates. The intranasal encephalocele in case 1 was removed endoscopically while the subcutaneous encephalocele in case 2 was excised through an open incision.

Results Forehead sloping was assessed using the fetal profile (FP) line, defined as the line that passes through the anterior border of the mandible and nasion, on pre- and postoperative MRI in the midsagittal plane. A FP line anterior to the forehead was “−,” while a posterior FP line was “+.” The largest distance from the FP line to the forehead was measured. Preoperatively, the FP line was −20.6 mm in case 1 and −9.8 mm in case 2. In both cases, follow-up MRI showed excellent reversal of sloping and normal development of the calvarium. The FP line improved to +7.4 (age of 16 months) in case 1, and +7.6 (age of 11 months) in case 2. The parietal bone donor site ossified completely within 3 months in both cases. Neither child developed hydrocephalus nor endocrinopathies.

Conclusion The described surgical approach for congenital frontoethmoidal encephaloceles is safe and effective. Early repair can promote normal frontal lobe and calvarial development and improve forehead sloping. The FP line is a useful method to measure degree of forehead slope.