Progressive midbrain clefts after head trauma and decompressive surgery: a report of two patients.

This report describes two patients with acute-onset ptosis, oculomotor dysfunction, ataxia and drowsiness, referable to the midbrain tegmentum. Both patients had previously suffered severe closed head injuries requiring craniotomy for cerebral decompression. Serial brain scans in both cases revealed a newly developing cleft in the midbrain, with features suggestive of abnormal cerebrospinal fluid (CSF) flow across the aqueduct. A trial of acetazolamide was initiated to reduce CSF production, followed by a third ventriculostomy for CSF diversion in one patient, which resulted in arrested disease progression and partial recovery. There are only two previous reports in the literature of midbrain clefts that developed as remote sequelae of head trauma. We postulate that altered CSF flow dynamics in the aqueduct, possibly related to changes in brain compliance, may be contributory. Early recognition and treatment may prevent irreversible structural injury and possible death.

Clinical Usefulness of Transcranial Doppler as a Screening Tool for Early Cerebral Hypoxic Episodes in Patients with Moderate and Severe Traumatic Brain Injury.

BACKGROUND: Brain tissue oxygenation (PbtO2) in traumatic brain injury (TBI) is known to be dependent on cerebral blood flow (CBF) which remains difficult to assess during the very early phase of TBI management. This study evaluates if blood flow velocity measurement with 2D color-coded transcranial Doppler (TCD) can predict cerebral hypoxic episodes in moderate-to-severe TBI measured with a PbtO2 probe. METHODS: This is a prospective observational study of serial TCD measurements to assess blood flow velocity and its association with PbtO2. Measurements were done bilaterally on the middle cerebral artery (MCA) early after the insertion of PbtO2 monitoring, daily for 5 days and during dynamic challenge tests. Physiological parameters affecting PbtO2 and Doppler velocities were collected simultaneously (PaO2, PaCO2, hemoglobin [Hb] level, intracranial pressure, and cerebral perfusion pressure [CPP]). RESULTS: We enrolled 17 consecutive patients with a total of 85 TCD studies. Using 2D color-coded TCD, signal acquisition was successful in 96% of the cases. Twenty-nine (34%) TCD measures were performed during an episode of cerebral hypoxia (PbtO2 ≤ 20 mmHg). For early episodes of cerebral hypoxia (occurring ≤ 24 h from trauma), all Vmean < 40 cm/s were associated with an ipsilateral PbtO2 ≤ 20 mmHg (positive predictive value 100%). However, when considering all readings over the course of the study, however, we found no correlation between PbtO2 and MCA's mean blood flow velocity (Vmean). Vmean is also positively correlated with PaCO2, whereas PbtO2 is also correlated with PaO2, CPP, and Hb level. CONCLUSIONS: Early TCD measurements compatible with low CBF (mean velocity < 40 cm/s) detect brain tissue hypoxia early after TBI (≤ 24 h) and could potentially be used as a screening tool before invasive monitoring insertion to help minimize time-sensitive secondary injury. Various factors influence the relationship between Vmean and PbtO2, affecting interpretation of their interaction after 24 h.

Successful Revascularization of Aortic Arch in a 39-Year-Old Blunt Trauma Patient with Acute Diffuse Axonal Injury without the Use of Systemic Anticoagulation.

Blunt traumatic aortic injury is the second leading cause of death in trauma patients aged 4-34 years. Of the patients who are able to receive treatment, mortality rates as high as 40% have been reported. Endovascular repair options have allowed for more expeditious repairs with reduced iatrogenic trauma; however, when the injury involves the ascending aorta or arch, current endografts lack fenestrations needed for cerebral blood flow. Traditionally, on pump, cardiopulmonary bypass with systemic anticoagulation has been used to repair these injuries. In this paper, we describe a unique case of repairing a large traumatic aortic arch pseudoaneurysm in the setting of which systemic anticoagulation is contraindicated. The patient is a 39-year-old otherwise healthy Hispanic male who presented to Ryder Trauma Center in Miami, Florida, following a motor vehicle collision and found to have multiple intracranial hemorrhages and a large aortic pseudoaneurysm of the distal ascending aorta. In lieu of standard cardiopulmonary bypass, a hybrid approach was utilized. Cranial blood flow was maintained using a temporary extra-anatomical left femoral to bilateral carotid bypass during endovascular coverage of the aortic arch. Aortic arch revascularization was then achieved by means of in situ laser fenestration of the innominate artery followed by a right-to-left carotid-carotid-subclavian bypass. This case demonstrates the viability of a hybrid vascular repair of a complex aortic disruption without the use of systemic anticoagulation in the setting of contraindicated or unknown risk of systemic anticoagulation. Further research is warranted on whether emergent traumatic cases with contraindications to anticoagulation can be performed in a similar fashion to safely reduce the morbidity and mortality associated with aortic disruptions.