Compound elevated skull fracture mimicking a frontotemporoorbitozygomatic craniotomy flap

Rajeev Sharma, Praveen Saligouda, Dhananjaya I Bhat, Bhagavatula Indira Devi 
 Department of Neurosurgery, National Institute of Mental Health and Neurosciences (NIMHANS), Bangalore, Karnataka, India

Correspondence Address:
Bhagavatula Indira Devi
Department of Neurosurgery, National Institute of Mental Health and Neurosciences (NIMHANS), Bangalore, Karnataka
India

Full Text

Sir,

Elevated skull fracture is defined as fracture in which a fractured bone segment is elevated above the level of the intact skull. [1] We report a very rare and interesting case of traumatic bone flap avulsion, which resembled a surgical craniotomy flap in size and shape.

A 25-year-old male, who had hit a roadside electric pole while driving a bike under the influence of alcohol presented to emergency department in an unconscious state. He was hemodynamically stable and there was no polytrauma. He was not opening eyes to pain, not obeying but localising, making incomprehensible sounds, pupils were equal and reacting, and there were no focal deficits. There was a large left frontotemporal degloving scalp injury with elevated underlying bone fracture segment adhered to the avulsed scalp flap [Figure 1]a. Dural tears were seen in the exposed dura, through which cerebrospinal fluid (CSF) was leaking and pulsating brain matter could be seen. Computed tomography (CT) head [Figure 1]b-d showed a left frontotemporoorbitozygomatic elevated skull fracture (single piece) involving lateral and superior orbital roof and left frontal sinus and small contusions in the underlying brain. He underwent wound debridement, thorough wound wash, repair of two dural tears using temporalis fascia graft, exteriorisation of frontal sinus using pericranial graft, reduction and fixation of elevated fracture segment, and two layered scalp wound closure after keeping sub-galeal suction wound drain. Fractured calvarial segment resembled a frontotemporoorbitozygomaticotomy bone flap in size and shape. Holes were drilled at margins of bone flap and bone flap was fixed to adjacent bone and soft tissues using silk threads. Postoperative recovery was uneventful [Figure 2]. Scalp wound was healthy at one month follow up.{Figure 1}{Figure 2}

Fractured calvarial segment can be elevated due to the following mechanisms: (1) injury caused by a sharp heavy object which elevates the skull fracture by lateral pull of weapon; (2) elevation of free fragment while retrieving the weapon; and (3) tangential force applied to the calvarium associated with rotation of head. [2],[3] Application of tangential force seems to be the mechanism of elevation of bone flap in our patient. Because much of the force is dissipated tangential to the cortical surface and away from it, the degree of scalp and bone injury may be relatively large compared to that of the underlying brain. [4] Extent of injury to brain and its coverings actually depends on the depth of weapon penetration and intensity of impact. CT head plain with bone windows is the investigation of choice because it demonstrates brain and bone injury as well as associated cerebral oedema and hematomas (extra/subdural or intraparenchymal) very well. [3],[5] The surgical principles of management is identical to those of compound depressed fractures with the elevated bone fragments being replaced into position after evacuation of hematoma, thorough wash, and proper closure of the dura. [1],[2],[5],[6] The large bone segment can either be removed or repositioned depending on degree of contamination and quality of debridement. [3],[6] If appropriately managed in time, these injuries have a favourable prognosis as in our case. On reviewing the literature, we came across three case reports of calvarial avulsion injury mimicking craniotomy flap. [6],[7],[8] However, ours is the first patient in the literature in whom avulsed bone flap resembled frontotemporoorbitozygomaticotomy bone flap in size and shape.

 Acknowledgement

References