Growing Skull Fracture (GSF) is a late complication of head trauma. It is commonly seen in children less than 3 years of age [1,2]. It can be seen in adults too but extremely rare [3,4]. Fractures of skull which are asymptomatic at the time of trauma may lead to GSF over time which may remain undetected for few weeks to years. Delay in diagnosis and treatment can lead to devastating complications. Early identification of symptoms and prompt management are critical to achieving a good outcome. Vascular injuries associated with skull fractures can be fatal. Traumatic pseudoaneurysm of internal carotid artery presenting with epistaxis is potentially life threatening. Delayed presentation and failure to recognize underlying pathology are associated to increased morbidity and mortality. Epistaxis may be recurrent and at times massive [5,6]. Endovascular therapy is ideal choice with options of parent artery occlusion or preserving the artery depending upon adequacy of cross circulation. This case is unique in a way that GSF is due to protruding traumatic pseudoaneurysm as against neuronal tissues or cerebrospinal fluid in typical case of GSF. Mechanism underlying this entity, its diagnosis and treatment options are discussed. We followed CARE guidelines while reporting this case .
49 years old villager presented to emergency medical department of our tertiary care hospital in one late evening with massive epistaxis. He had a fall on the head in his farm one year back from which he had recovered completely. No CT scan was done at that time. By the time he reached our hospital he had lost one liter of blood. On inquiring he gave history of recurrent epistaxis since one month. He had undergone CT angiography at other hospital in the city which showed pseuoaneurysm of cavernous segment of right Internal Carotid Artery (ICA). He already had nasal packing. On clinical evaluation his blood pressure was 110/70 and continuously dropping. His hemoglobin had dropped to 6 gm%. He was conscious and oriented in time place and person. We immediately took him for DSA which confirmed pseuoaneurysm of cavernous segment of ICA projecting medially into sphenoid sinus. Balloon Test Occlusion (BTO) test was done under local anesthesia. He withstood the BTO. This was followed by endovascular coil embolization along with sacrificing the artery. Option of preserving artery was not considered as it would have required to start him on anteplatelet agents which could have been detrimental considering massive epistaxis with deteriorating blood pressure. Fortunately he tolerated the balloon test occlusion. Procedure went off without any complications. His Blood pressure started stabilizing with transfusion of two units of whole blood and intravenous volume expanders. Post procedure CT scan showed coil mass projecting into the right sphenoid sinus. We reviewed his CT angiogram which showed pseuoaneurysm of the cavernous segment of ICA projecting through well defined defect in lateral bony wall of sphenoid sinus (Figure 1 A-H).
Sphenoid sinuses are paired pneumatic spaces lined with mucosa, located within the body of the sphenoid bone. Their morphology is highly variable. They are separated by septum which is rarely placed in the midline. It is characterized by an oblique course resulting in to asymmetrical spaces. In case of strongly aerated sinuses, the structures located in the nearest vicinity of the sinus may be separated only by very thin bony lamina. Additionally it may contain bony dehiscence . The lumen of the cavernous sinus is traversed by the siphon of the internal carotid artery and the Abducens nerve (VI cranial nerve).While within the lateral wall of the sinus there are Oculomotor , Trochlear nerve, Ophthalmic nerve (first division of the trigeminal nerve), Maxillary nerve (second division of the trigeminal nerve). The medial and lateral walls of the cavernous sinus consists of dense collagen fibers forming the endosteal and the meningeal layers .
Pseudoaneurysms are formed due to tear across all layers of arterial wall resulting into perivascular hematoma. Recanalization of this hematoma communicating with the arterial lumen turns into the pseudoaneurysm. It is lined by only organized hematoma or surrounding soft tissues. Hence it is more prone to re-rupture and growth than true aneurysms.
The expanding force of the growing brain tissues and pulsations of cerebrospinal fluid are traditionally implicated as principle causative factors for GSF. Weakness of surrounding tissue can act as path of least resistance . Posttraumatic pseudo-meningocele or encephalocele should also be included in the spectrum of GSF . We believe this patient had fracture of right lateral wall of sphenoid sinus due to fall on head. He did not undergo CT scan immediately after the fall and was managed conservatively. The injury to the cavernous segment of ICA had lead to formation of pseudoaneurysm overlying the fracture. Over the six months this pseudoaneurysm must have been growing resulting into expanded the margins of fracture. The bony defect was large with smooth and splayed out margins. Continuous pulsations of the pseudoaneurysm through defect in dural layer overlying the fractured bony margins must have lead to GSF (Figure 1 A-D).
GSF of roof (cribriform plate) of ethmoid sinus, orbital roof and mastoid cavity with protrusion of adjacent brain tissues or CSF space has been reported [11-13]. Even GSF overlying superior sagittal sinus has been reported . But growing fracture due to pulsations of traumatic pseudoaneurysm has not been reported yet. We believe this is first reported case of the GSF due to pseudoaneurysm. Since a growing fracture of skull vault are easily noticeable but skull base growing fractures are difficult to identify from the outside. It is very important to follow-up changes in the fracture line from the acute stage of injury. CT scan with high resolution bone windowing is primary investigation of choice. When skull base fracture particularly through sphenoid , petrous and temporal bones are seen then CT Angiography (CTA) should be done. DSA is gold standard for confirming or ruling out vascular injuries. Advantage of DSA is endovascular treatment can be offered in the same setting. Angiography negative cases of skull base fractures are closely followed clinically for any delayed vascular complications like bleeding from natural orifices of the head and face.
Endovascular treatment is ideal in vascular injuries of skull. If adequate cross flow is seen and patient withstood Balloon Test Occlusion (BTO), it is followed by parent artery occlusion. Detachable coils or vascular plugs or rarely balloons or combination of these devices are used for the same. Adequacy of cross flow was decided during BTO. Both clinical and angiographic evaluations were carried out. Clinically patient should not show any focal or global neurological deficit. Angiographically there should be synchronous phlebogram with delay of not more than 2 seconds . We prefer coils and or vascular plugs or combination of these two for parent artery occlusion (Figure 1 E-H). If patient did not withstand BTO then vessel preserving approach is considered with covered stents or endovascular flow diverter stents.
This case highlights importance of CT angiography whenever skull base fractures are seen following head injury.GSF due to traumatic pseudoaneurysm is rare but possible. This is first reported case to our knowledge. Head injuries with skull base fracture needs to be followed up for possible sequel of vascular injury over next several months. Endovascular treatment with BTO followed by parent artery occlusion is ideal and durable treatment option in this case.
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