Case 24 Answers

by Dr.Chua
 

This 4-month-old boy was seen by the ENT team of the Sarawak General Hospital, Kuching during a camp trip to a border village near Indonesia. The swelling has been present since birth and has a flatulent feel. The swelling showed transillumination. Examination of the eye appears normal except for a slight restriction of right adduction.

Figure 1. A large cystic swelling arising from the right medial canthus causing distortion

of the right medial canthus and right nostril.

Figure 2. Transillumination of the swelling shown with a torchlight.

The CT scan and bony reconstruction are as shown below.

Figure 3. CT bony reconstruction showing a defect in the floor at the right side of the anterior

cranial fossa at the junction of the frontal, ethmoid, lacrimal, maxillary and nasal bone.

Figure 4. CT scan shows herniation of part of the frontal lobe and CSF through the defect

into a subcutaneous pouch There is right subdural collection at the fronto-temporal-parietal

region. There is a smal midline shift.

a. What is the diagnosis?

Meningoenceophalocele.

 

Meningoenceophalocele is a form of anterior cranial fossa encephaloceles which refers to congenital herniations of intracerebral contents from the anterior cranial fossa through a defect in the facial skeleton^1-2.
 

There are different types of encephalocele depending on the contents:

• meningocele = meninges alone

• meningoencephalocele = meninges and brain

• hydroencephalomeningocele =  meningoencephalocele + ventricle
   

Encephaloceles can also be described according to its location. This boy has a naso-orbital frontoethmoidal because the herniations of the intracranial contents are through a defect in the skull at the junction of the frontal and ethmoidal bones and through the medial wall of the orbit.

b. How can the medial canthus be reconstructed after the neurosurgeon and ENT surgeons have replaced the brain and close the defects?

 

Following closure of the skeletal framework, the medial canthal ligaments are isolated taking to protect the lacrimal apparatus (this can be cannulated when necessary to avoid accidental damage during the operation). The ligaments are transfixed using 30-guage wire and canthopexies are performed at the same level as the opposite eye ideally by joining the wires across the midline. The excess skin is excised vertically and the wound closed along the side of the nose³.

References:

1. Suwanwela C, Suwanwela N. A morphological classification of sincipital encephalomeningoceles. J Neurosurg 1972;36:201–211.

2. David DJ, Sheffield L, Simpson D, White J. Fronto-ethmoidal meningo-encephaloceles: morphology and treatment. Br J Plast Surg 1984;37:271–284.

3. Surgery of the Eyelid, Orbit, and Lacrimal System : Volume 1 - 3 (American Academy of Ophthalmology Monograph Series) (Paperback).