Virtual autopsy to assess sacral anatomy: Conditions for a minimal invasive approach to the spinal canal through the hiatus sacralis

Post-mortem Imaging of Brain/Spine Injuries: The Importance of a Comprehensive Forensic Approach

In forensic investigations, the limitations of the traditional purely autoptic approach can be overcome through post-mortem imaging (virtopsy). Virtospy has several applications to the investigation of brain and spinal injuries, whose analysis can be of forensic interest, especially in cases of suspected malpractice. In this scoping review, we briefly describe the main applications of the two most common post-mortem radiological techniques (computed tomography (CT) and magnetic resonance imaging (MRI)) to the forensic investigation of brain and spinal injuries in cases of medical malpractice or traumatic (accidental/homicidal/suicidal) deaths. Although CT represents the traditional approach to post-mortem imaging, MRI is proving to be a valuable tool to investigate brain and spinal injuries and lesions. These post-mortem radiological techniques can also be used to guide the surgeons in simulated surgical procedures on corpses in the context of training programs, thus helping operators to improve technical and non-technical skills and to reduce the risk of avoidable errors.

Imaging anatomy of the vertebral canal for trans-sacral hiatus puncture of the lumbar cistern

A standard lumbar puncture may be impossible for many anatomic or technical reasons. Previous accounts of caudal epidural anesthesia and other procedures via the sacral hiatus prompted us to test if image-guided percutaneous trans-sacral hiatus access to the lumbosacral subarachnoid cistern would be anatomically feasible. To study vertebral canal morphometry and curvature, we analyzed midsagittal computed tomography-myelogram images of 40 normal subjects and digitally measured sacral curvatures between S1 to S5 and S2 to S4 using two methods whereby a lower angle signifies a straighter sacrum. We measured midsagittal vertebral canal area, hiatus width, dural sac termination levels, and distance from sacral hiatus to the dural sac tip (needle distance). Subjects were F:M = 25:15, with a mean age of 44.9 years. The two S1-S5 full sacral curvature mean angles were 57.3° and 60.4°. Almost all sacral hiatuses were at S4, and dural sac terminations were at S1-S2. The mean S2-S4 sacral curvature was 25.1°, and the mean needle distance was 57.7 mm. Using two-way analysis of variance, there were significant sex differences for needle distances (p = .001), and full and limited sacral curvatures (p = .02, and p = .046, respectively). There were no significant linear regression correlations between age and sacral curvature, needle distance, canal area, or hiatus width. Therefore, despite a frequently prominent full sacral curvature, the combination of S1-S2 dural sac termination plus a relatively straight trajectory of the lower vertebral canal between S2 and S4 support the theoretical feasibility of percutaneous trans-sacral hiatus and vertebral canal access to the lumbosacral cistern using a standard spinal needle.