Limited Clinical Relevance of Vertebral Artery Injury in Blunt Trauma.

BACKGROUND: Blunt cerebrovascular injury (BCVI), although rare, is more common than previously thought and carries a substantial stroke and mortality risk. The purpose of our study was to evaluate the differences between blunt carotid artery (CA) and vertebral artery (VA) injuries, assess the stroke and death rates related to these injuries, and identify the relationship of Injury Severity Score (ISS) with stroke and mortality in BCVI. METHODS: Using a retrospective review of the trauma registry at a level I trauma center, we identified patients with BCVI. The study period began in January 2003 and ended in July 2014. Demographics, injuries reported, investigative studies performed, and outcomes data were obtained and analyzed. Radiographic images of both blunt CA and VA injuries were reviewed and graded by an independent radiologist, according to the current classification of blunt CA injuries. RESULTS: BCVI involving 114 vessels was identified in 103 patients. This population consisted of 65 males and 38 females with an average age of 45 years (15-92, range). The average ISS was 22 (4-75, range). Cervical spine fracture occurred in 80% of VA injuries (64 total patients). Injuries involved the CA in 33, the VA in 59, and both in 11. The CA group had a higher incidence of traumatic brain injury (61% vs. 46%), ISS (27 vs. 18), and stroke (24% vs. 3%), compared to the VA group. Mortality in the CA group was 30% compared to 3% in the VA group. Patients with high ISS (≥25) had increased stroke rates compared to those with lower (<25) ISS (19% vs. 6.7%). All mortalities occurred with ISS >25. Logistic regression revealed that vessel injured, ISS, and Glasgow Coma Scale (GCS) were significant risk factors for mortality. Multivariate analysis demonstrated carotid injury, and lowest GCS were independently associated with mortality. CONCLUSIONS: In this comparison of CA and VA injuries in BCVI, VA injuries were more common and more frequently found with cervical spine fractures than CA injuries. However, VA injuries had a lower incidence of CVA and mortality. A high ISS was associated with stroke and mortality while carotid injury and lowest GCS were independently associated with increased mortality.

Acute Cerebellar Stroke in a Military Active-Duty Pilot.

BACKGROUND: Cryptogenic stroke leading to cerebellar infarction is a rare but serious cause of acute nausea and vomiting. This has the potential of devastating consequences if this occurs in aviators during flight. We present a case of cryptogenic stroke causing incapacitating nausea and vomiting in a U.S. Air Force pilot.CASE REPORT: A 36-yr-old active-duty U.S. Air Force male pilot developed acute onset severe vertigo, nausea, and vomiting during initial descent. Initial computed tomography imaging was normal and his initial assessment yielded a diagnosis of benign paroxysmal positional vertigo. MRI-Brain at 1 mo revealed a small right inferomedial cerebellar infarct. Echocardiography revealed a patent foramen ovale and bilateral atrial enlargement. He made a full neurological recovery and was eventually returned to active flight status with Flying Class IIC waiver.DISCUSSION: Cryptogenic stroke caused by patent foramen ovale (PFO) is uncommon. However, this is increased in patients younger than 50 yr of age. This can lead to an acute incapacitation with varying degrees of dysfunction. There is controversial discussion of treatment options for secondary stroke prevention with PFO. However, there is no significant literature on primary prevention in these patients. A small subset of patients benefit from closure of PFO and most patients benefit from antiplatelet therapy after a stroke occurs. There may also be a significant subset of patients with PFO that may benefit from antiplatelet therapy as a primary prevention of stroke.Lytle ME, Martin BR. Acute cerebellar stroke in a military active-duty pilot. Aerosp Med Hum Perform. 2021; 92(11): 919-923.

A Case of Posterior Nutcracker Syndrome Revealed in the Aerospace Environment.

BACKGROUND: Nutcracker syndrome is caused by a rare anatomic variant where the left renal vein is trapped between the aorta and the superior mesenteric artery. Posterior nutcracker syndrome is an even rarer entity, characterized by the retro-aortic positioning of the renal vein, causing compression between the aorta and spinal vertebrae. Symptoms include microscopic or frank hematuria, flank pain, varicocele, pelvic congestion syndrome, and abdominal pain. A search of the literature did not reveal prior cases of nutcracker syndrome that became symptomatic and diagnosed secondary to the unique stressors of high gravitational force (G force) in the aviation environment.CASE REPORT: A 25-yr-old man training as an F-16 flight test engineer presented with left scrotal/testicular pain, varicocele, and intermittent gross hematuria. After an extensive workup, he was diagnosed with posterior nutcracker syndrome and underwent a left varicocele ligation with spermatic cord denervation. He was eventually able to be returned to flying duties with limitation to non-high performance aircraft.DISCUSSION: This case is particularly unique as its diagnosis was dependent on exposure to high G force conditions that may have otherwise remained asymptomatic without this environmental stressor. Education on the diagnosis of nutcracker syndrome as a differential in the setting of hematuria and pain is an important lesson learned. This case also illustrates the necessity of considering the effects of the stressful environment of high G force on even overall healthy individuals. Fortunately, due to the collaboration of medical-surgical expertise and familiarity with the requirements for operational readiness, this patient was able to resume his aviation career, albeit in a different capacity compatible with his condition.Chung CY, Lytle ME, Clemente Fuentes RW. A case of posterior nutcracker syndrome revealed in the aerospace environment. Aerosp Med Hum Perform. 2021; 92(1):5456.