A U.S. Army Specialist’s vehicle was flipped by a 150-pound improvised explosive device in Southern Baghdad while on patrol. He suffered a severe polytraumatic injury, including a left temporal skull fracture, a subdural hematoma with >5 mm shift, an epidural hematoma, an L5 vertebral fracture, open fractures in three limbs, and fractures to all major facial structures. He was rapidly evacuated out of combat for emergent medical and surgical resuscitation and care, including a craniectomy within the first 12 hrs to relieve intracranial pressure.
Over the next 3 mos, he underwent 11 major operative procedures. His intracranial pressures were noted to be continually high in the range of 20–30 mm Hg. Posttraumatic hydrocephalus (PTH) was treated by placement of a ventriculoperitoneal shunt in his left third ventricle. The shunt rapidly resolved the enlargement of his proximal ventricular system. Despite this effect, the patient was noted to have a persistently enlarged fourth ventricle.
Five months after injury, he was transferred to the Emerging Consciousness program at the Richmond Veterans Administration Polytrauma Rehabilitation Center. On admission, he continued to display inconsistent levels of arousal and awareness of his environment. After re-establishment of physiologic sleep–wake cycles and with pharmacologic neurostimulation, the patient would track visually and communicate with sign language 1–2 hrs/day. In the brief moments of clarity, he was oriented to person, place, and year. Volitional movements were noted only in his right upper limb.
A head computed tomographic scan revealed unchanged size of the known fourth ventricular enlargement. In consultation with a neuroradiologist, a magnetic resonance imaging of the patient’s head and spinal cord was obtained. The scan revealed a robust syrinx propagated through the central canal of his spinal cord, extending from the base of his fourth ventricle to the level of T12 (Figs. 1 and 2). Also noted was ongoing, marked dilation of the fourth ventricle and slight inferior cerebellar tonsillar herniation through the foramen magnum. In consultation with a neurosurgeon, it was concluded that the likely etiology was blockage of the Sylvian aqueduct. This in turn led to isolated, increased fourth ventricular pressure and retrograde syrinx formation.
PTH is a known complication of traumatic brain injury.1,2 Definitive treatment for PTH is through placement of a third ventricular shunt,1,2 which was successfully done in this case. As PTH results from impaired cerebrospinal fluid resorption, the fourth ventricle typically drains appropriately through the shunt. In this case, there exists presence of both communicating hydrocephalus (impaired cerebrospinal fluid resorption) and a noncommunicating hydrocephalus (blockage of the Sylvian Aqueduct). There have been scattered published case studies regarding syrinx formation from increased intracranial pressure.3,4 The patients in the previously published reports were all successfully treated with third ventricular shunting. This case represents an exceedingly rare variant of PTH. It is perhaps the only reported case of a syringomyelia developing from isolated posterior fossa hydrocephalus in the setting of a successfully shunted third ventricle.
1. Bergsneider M: Management of hydrocephalus with programmable valves after traumatic brain injury and subarachnoid hemorrhage. Curr Opin Neurol
2. Katz RT, Brander V, Sahgal V: Updates on the diagnosis and management of posttraumatic hydrocephalus. Am J Phys Med Rehabil
3. Mohanty A, Suman R, Shankar SR, et al: Endoscopic third ventriculostomy in the management of Chiari I malformation and syringomyelia associated with hydrocephalus. Clin Neurol Neurosurg
© 2008 Lippincott Williams & Wilkins, Inc.
4. Raja AI, Adada B: Immediate resolution of tonsillar herniation and severe cervicothoracic syringomyelia after third ventriculostomy for hydrocephalus caused by a brainstem tumor. Case report. J Neurosurg