Traumatic orbital encephalocele in an infant: using the fracture line to our advantage

Abstract

Dear Editor, Traumatic encephalocele secondary to orbital roof fracture, though uncommon, has been reported in the past [3]. These cases warrant early intervention due to progressive proptosis and possible optic nerve compression due to raised intraorbital pressure. Apart from watertight dural closure, restoration of orbital contours is equally important to prevent post operative enophthalmos and transmitted pulsations [5]. Frontal craniotomy with repair of the dural defect and bony reconstruction with mesh is a standard procedure described in literature so far [2]. However, it is not desirable to use mesh in an infant. We describe here a unique method using the fracture line as one of the edges of the craniotomy to minimize bone loss, thereby achieving good cosmetic outcome without compromising the surgical exposure. A 6-month-old child presented with head injury due to a fall from a 20-ft height. Initially the child was unresponsive with GCS 4 and was put on mechanical ventilation. The immediate post-injury CT scan showed left-sided frontal contusion associated with frontobasal fracture extending across the orbital roof longitudinally, reaching just short of the optic canal (Fig. 1A, B). The child gradually improved. However, 3 weeks later, parents noticed progressive proptosis and increasing conjunctival edema of the left eye. Reconstructed CT and MRI showed herniation of brain matter into the left orbit through that fracture line (Fig. 1C-J). He was operated on through a curvilinear incision behind the hair line. Frontoorbital craniotomy was performed using the fracture line of the orbital roof and frontal bone as edges of the craniotomy (monobloc frontoorbital craniotomy). The lateral wall of the orbit was cut using a saw to reach up to the temporal base from where it was connected to the remaining craniotomy. This gave access to both the orbital and intracranial contents without the need to remove additional parts of the orbital roof. The underlying dural defect was completely delineated. Herniated brain parenchyma was resected, and a watertight dural closure was done. The bone flap was replaced in its normal anatomical position. A good cosmetic outcome was achieved. Proptosis reduced and there was no enophthalmos after a follow-up at 2 months (Fig. 1K-Q). However, a long-term follow-up is required, as recurrence is possible. Post-traumatic orbital encephalocele is rare among all the varieties of growing skull fractures. The mechanism of injury may be attributable to the under-developed frontal sinus, which is unable to dissipate the pressure over the orbital rim in patients below the age of 7 years [1]. The brain parenchyma may herniate through the underlying dural defect, resulting in orbital encephalocele. The usual clinical presentations are pulsatile exophthalmos, diplopia, lid swelling, and orbital asymmetry. The optic nerve is at risk due to raised intra-orbital pressure, and thus, immediate intervention is warranted in cases of traumatic orbital encephalocele [1, 4]. In all cases described to date, the herniated brain parenchyma into the orbit was accessed through a frontal craniotomy followed by nibbling of the orbital roof or removal of its fractured fragments [2]. Though the dural repair was very well achieved by this, the bone loss is likely to result in enophthalmos and feelings of transmitted pulsations in the orbit. A mesh repair S. K. Sahoo : P. S. Salunke (*) Department of Neurosurgery, PGIMER, Sector 12, Chandigarh 1600l2, India e-mail: drpravin_salunke@yahoo.co.uk