Extracranial vertebral artery injury — evolution of a pathological illusion?

Traumatic basal subarachnoid hemorrhage caused by minor blunt trauma to the head or neck can lead to rapid collapse and death. The vertebral arteries are the vessels most commonly involved in such cases, but it is very difficult to find the bleeding focus in the vertebral arteries in routine autopsy because of the location of these vessels. Using the posterior neck dissection method, which is relatively easy and avoids artificial damage to the intracranial portion of the vertebral arteries, authors have identified tear sites in the intracranial artery in four out of five consecutive traumatic basal subarachnoid hemorrhage cases. In this report we show that this new method is useful for cases of traumatic basal subarachnoid hemorrhage.

Traumatic basal subarachnoid haemorrhage (TBSH) following trauma to the head, face or neck is well-established as a cause of death; however it remains a heavily disputed topic as the site of vascular injury is difficult to identify. Whilst many regions within the vasculature of the head and neck have been proposed as more susceptible to rupture, the vertebral artery remains the focal point of many investigations. We present a retrospective case review of TBSH in our forensic centre at Forensic and Scientific Services in Brisbane, Australia, from 2003 to 2011. Thirteen cases of TBSH were found, one case excluded due to vasculopathy. All decedents were male, the majority of which were involved in an altercation receiving blows to the head, face, or neck and were unconscious at the scene. All victims were under the influence of alcohol, drugs, or a combination thereof. External examination revealed injuries to the head, face, and neck in all cases. Various combinations of further examination techniques were used during the post-mortem examination including brain and/or cervical spine retention, CT imaging, and angiography. Vascular injury was identified in eight of the twelve cases, all of which occurred intracranially, with seven involving the vertebral artery. Histology was most reliable in identifying the rupture site and angiography failed to reveal a rupture site. The added benefits of histology over angiography are the ability to identify the microscopic architecture of the tear and to diagnose vasculopathy that may have rendered the individual more susceptible to TBSH.

Traumatic basal subarachnoid hemorrhage (TBSAH) is infrequent but of forensic neuropathological importance because of its high mortality and complex causal mechanisms. The source of the hemorrhage is most frequently identified in the vertebro-basilar arteries but often cannot be identified in these arteries. We present a case of TBSAH possibly originating from hemorrhagic cerebellar contusions due to fist blows to the neck. A 35-year-old woman, who was punched on the right side of the neck, became unconscious about 20 min later and died. Autopsy demonstrated a massive subarachnoid hemorrhage at the base of the brain, with blood clots attached to the right lower surface of the cerebellum. No tear was detected in the vertebro-basilar vessels, but there were hemorrhagic cerebellar contusions beneath the blood clots as a possible source of TBSAH. The site of impact to the neck suggested the cerebellar contusions to be a coup injury due to hard blows.

The most common cause of basal cerebral subarachnoid hemorrhage (SAH) is rupture of a cerebral artery aneurysm, but most reported series of SAH include cases where no aneurysm could be found. This would have no forensic relevance if all basal SAH would result from spontaneous ruptures of pathological blood vessels, but the situation is more complex because traumatic ruptures of otherwise normal cerebral arteries may be the only intracranial result of an injury. From the gross appearance, these two types of basal SAH cannot be distinguished. In victims with external injuries and in cases with doubtful circumstances, the detection and (histological) classification of the bleeding point(s) is necessary to distinguish between a spontaneous and traumatic origin of the rupture. We recommend post-mortem radiological examination of the cerebral arteries after instillation of a contrast medium. This method probably allows detection of even small bleeding points in the most inaccessible locations (not present in our actual series), and the radiological appearance of the bleeding points can also be helpful in the identification of the type of arterial alteration.

One of the most difficult tasks in forensic medicine is deciding the cause of death in an unclear or debatable case. Most decision-making difficulties arise when there is a definite or potential causal interaction between: disease, injury, and circumstantial events. Sometimes these interactions are trivial, but in many instances the causal interaction is undeniably important, potentially important, or of uncertain relevance. In some cases, the cause of death may be unascertainable despite best efforts, and the pathologist must resist attempts at a presumptive, but objectively un-substantiated diagnosis. In general, there are three major categories that lead to difficulties: (i) co-existence of a pre-existing condition and a fatal injury; (ii) competing potential causes of death; (iii) historical events may be causally relevant to death by injury. In this review, these categories are discussed in detail and illustrated with relevant examples.