Neck structure injuries in Hanging--comparing retrospective and prospective studies

Assessing the knot in a noose position by thyrohyoid and cervical spine fracture patterns in suicidal hangings using machine learning algorithms: A new insight into old dilemmas

Hanging is one of the most common suicide methods worldwide. Neck injuries that occur upon such neck compression - fractures of the thyrohyoid complex and cervical spine, occupy forensic pathologists for a long time. However, research failed to identify particular patterns of these injuries corresponding to the force distribution a ligature applies to the neck: the issue of reconstructing the knot in a noose position persists. So far, machine learning (ML) models were not utilized to classify knot positions and reconstruct this event. We conducted a single-institutional, retrospective study on 1235 autopsy cases of suicidal hanging, developed several ML models, and assessed their classification performance in a stepwise manner to discriminate between: 1. typical ('posterior) and atypical ('anterior' and 'lateral') hangings, 2. anterior and lateral hangings, and 3. left and right lateral hangings. The variable coding was based on the presence/absence of fractures of greater hyoid bone horns (GHH), superior thyroid cartilage horns (STH), and cervical spine. Subject age was considered. The models' parameters were optimized by the Genetic Algorithm. The accuracy of ML models in the first step was very modest (c. 60%) but increased subsequently: Multilayer Perceptron - Artificial Neural Network and k-Nearest Neighbors performed excellently discriminating between left and right lateral hangings (accuracy 91.8% and 90.6%, respectively). The latter is of great importance for clarifying probable hanging fracture biomechanics. Alongside the conventional inferential statistical analysis we performed, our results further indicate the association of the knot position with ipsilateral GHH and contralateral STH fractures in lateral hangings. Moreover, odds for unilateral GHH fracture, simultaneous GHH and STH fractures, and cervical spine fracture were significantly higher in atypical ('anterior' and 'lateral') hangings, compared to typical ('posterior') hangings.

Pathological Findings in Hanging: Is the Traditional Knowledge Correct?

BACKGROUND

In forensic pathology, asphyxia presents a problem as frequently as it is thorny and challenging. Some knowledge in forensic pathology is still considered to be traditionally acquired and is not critically assessed with modern statistical or technical tools. In this study, we seek to examine the injuries that are considered to be typical of cases of hanging (neck lesions, haemorrhages, and pleural and epicardial petechiae).

METHODS

We evaluated whether there was, indeed, a statistically significant association between these injuries and deaths from hanging as compared to non-hanging deaths. We collected 399 cases (32 deaths by hanging and 367 cases of non-hangings), built contingency tables and performed chi-square tests for each variable (lesion) examined; we also analysed this association in various subgroups of the sample (according to sex, age and weight ranges).

RESULTS

Our results did not deviate from the expected outcome based on traditional knowledge, although they do provide a more detailed demonstration and clarification of traditional knowledge regarding this topic.

CONCLUSIONS

These findings provide valuable insights for future discussion, examination and deepening of knowledge that is traditionally accepted but often undersupported in the literature.

A meta-analytic review of the frequency and patterning of laryngohyoid and cervical fractures in cases of suicide by hanging

The frequency and distribution of fractures are commonly utilized to assist in interpreting the manner of death. In cases of alleged suicide by hanging, however, the evidence base for the frequency and patterning of laryngohyoid and cervical vertebrae fractures resulting from such blunt force traumatic events is limited and so fractures cannot be reliably used to assist in interpreting the manner. Using meta-analytic techniques, this study aimed to estimate frequency and distribution of fractures in the context of relevant intrinsic and extrinsic variables. A systematic review of the literature identified 20 studies with relevant data (8523 cases of suicide by hanging). Meta-analyses identified the frequency and distribution of fractures present and how fracture frequency was affected by the subgroups of age, sex, completeness of suspension, ligature knot position and study design. Results indicated that fracture frequency was variable, there was no unique patterning, and high levels of heterogeneity were present in all variable sub-groups. Age was the only subgroup to show differences. Findings suggest that neck fracture frequency is inconsistent and cannot be predicted by the chosen variables. Subsequently, neck fractures in isolation should not be given weight in medico-legal interpretations of a hanging death as suicidal.

[Dissection technique for organs of the neck in hanging]

The aim of this study is to develop a comprehensive dissection technique to examine the deep structures of the neck in hanging, including extraction of the cervical spine and investigation of the removed segment with access to vertebral arteries and spinal cord. Its advantages include the unnecessity of any special instruments usage, the short period of time, which is necessary for performing dissection techniques, as well as the possible detailed examination of the spine, spinal cord and vertebral arteries. The improved dissection technique simplifies the diagnosis of injuries and increases the objectivity of the forensic medical examination in hanging.

Correlation of soft tissue and skeletal injuries in cases of violent death: A retrospective study of autopsy cases for forensic anthropology

In forensic pathology, deaths due to mechanical injuries (blunt, sharp, and gunshot) require an autopsy in order to determine the cause and manner of death through a detailed examination of viscera, soft tissues, and the skeletal system. Sometimes, such as in cases of severe putrefaction, only the skeleton is observable. In such cases, the absence of bony defects does not mean that a trauma-related death should not be considered: yet, how often will a lethal mechanical death produce a defect in the skeletal system? The present study involved a retrospective review of autopsy reports to investigate the frequencies of soft tissue and related skeletal injuries in cases of violent deaths. A total of 200 autopsy reports for cases of four mechanisms of injury including sharp force trauma (n = 50), gunshot (n = 50), blunt force trauma (n = 50), and mechanical asphyxia (n = 50) were examined. Manner of death, localization of bone fractures, and correspondence between external injuries and bone fractures were reported. Frequencies of bone fractures and degree of correspondence with soft tissue injuries for each trauma group were evaluated. The result showed that lethal blunt trauma always caused bone fractures; 94.0% of violent deaths by gunshot involved bones; 48.0% of sharp force soft tissue injuries involved the bone tissue; and hyoid bone fractures were observed in 20.0% of cases of mechanical asphyxia.

Postmortem Magnetic Resonance Imaging and Postmortem Computed Tomography in Ligature and Manual Strangulation

PURPOSE

The aim of this study was to evaluate magnetic resonance imaging (MRI) findings in cases of fatal manual or ligature strangulation. Verification of strangulation by computed tomography (CT), MRI, and at autopsy as well as its detectability in each modality was assessed.

METHODS

We retrospectively analyzed 6 manual and ligature strangulation cases between 2013 and 2019 who all underwent a whole-body CT, head and neck MRI, and an autopsy. Two radiologists examined head and neck imaging data and compared the data to autopsy findings.

RESULTS

Magnetic resonance imaging showed a high efficiency in verifying intramuscular hemorrhages, which were confirmed in autopsy. Moreover, in one case without a visible strangulation mark, soft tissue injuries associated with strangulation were detected. Fractures, especially thyroid cartilage fractures, were successfully diagnosed by CT.

CONCLUSIONS

As MRI showed a successful detection of soft tissue lesions in relation to strangulation, it can serve as an alternative method or provide additional value to an autopsy. Intramuscular hemorrhages are a common finding in manual and ligature strangulation, providing a useful sign of applied pressure on the neck. However, to evaluate fractures, an additional CT or autopsy is recommended.

Evaluation of the potential killing performance of novel percussive and cervical dislocation tools in chicken cadavers

1. Four mechanical poultry killing devices; modified Armadillo (MARM), modified Rabbit Zinger (MZIN), modified pliers (MPLI) and a novel mechanical cervical dislocation (NMCD) gloved device, were assessed for their killing potential in the cadavers of euthanised birds. 2. A 4 × 4 × 4 factorial design (batch × device × bird type + age) was employed. Ten bird cadavers per bird type and age were tested with each of the 4 devices (N = 160 birds). All cadavers were examined post-mortem to establish the anatomical damage caused. 3. NMCD, MARM and MZIN demonstrated killing potential, as well as consistency in their anatomical effects. NMCD had the highest killing potential, with 100% of birds sustaining the required physical trauma to have caused rapid death. 4. The MPLI was inconsistent, and only performed optimally for 27.5% of birds. Severe crushing injury was seen in >50% of MPLI birds, suggesting that birds would die of asphyxia rather than cerebral ischaemia, a major welfare concern. As a result, the MPLI are not recommended as a humane on-farm killing device for chickens. 5. This experiment provides important data on the killing potential of untried novel percussive and mechanical cervical dislocation methods, informing future studies.

Hanging Fatalities in Central Bangkok, Thailand: A 13-Year Retrospective Study

Hanging is violent asphyxial death. The objective of this study is to assess the data of hanging cases. A descriptive-retrospective study was conducted. We studied 244 hanging cases autopsied in Forensic Division, Department of Pathology, Faculty of Medicine Ramathibodi Hospital, Mahidol University, Bangkok, Thailand, between January 2001 and December 2013. The study included 197 men (80.7%) and 47 women (19.2%). Their age ranged from 14 to 93 years. Most of these cases were incomplete hanging (83.6%). Features of hanging victims, such as tongue protrusion; congestion of face; petechial hemorrhage of face, conjunctiva, and internal organs; and neck injuries, significantly correlated with complete hanging. The predominant occupation of hanging victims was in the service industry (63.1%). Suicides usually occurred in private homes or apartments (84.8%). A suicide note was found in 6.1% of cases. The most common ligature material used was nylon rope, found in 61.1% of cases. The most underlying diseases of the victims in hanging cases were tuberculosis and human immunodeficiency virus infection, 9 cases each. Blood ethanol levels of 29 cases (11.8%) were detected to be higher than 150 mg%. Methamphetamine and benzodiazepine were detected in 5.3% and 3.3% of cases, respectively. This study provides comprehensive baseline data of hanging cases in central Bangkok.

An osteological revisitation of autopsies: comparing anthropological findings on exhumed skeletons to their respective autopsy reports in seven cases

Forensic anthropologists and pathologists are more and more requested to answer questions on bone trauma. However limitations still exist concerning the proper interpretation of bone fractures and bone lesions in general. Access to known skeletal populations which derive from cadavers (victims of violent deaths) who underwent autopsy and whose autopsy reports are available are obvious sources of information on what happens to bone trauma when subjected to taphonomic variables, such as burial, decomposition, postmortem chemical and mechanical insults; such skeletal collections are still however quite rare. This study presents the results of the comparative analysis between the autopsy findings on seven cadavers (six of which victims of blunt, sharp or gunshot wounds) and those of the anthropological assessment performed 20 years later on the exhumed dry bones (part of the Milano skeletal collection). The investigation allowed us to verify how perimortem sharp, blunt and gunshot lesions appear after a long inhumation period, whether they are still recognizable, and how many lesions are no longer detectable or were not detectable at all compared to the autopsy report. It also underlines the importance of creating skeletal collections with known information on cause of death and trauma.

Traumatic rupture of deep neck structures in hanging: two case reports

Injuries to the neck structures are various in case of hanging. Soft tissue lesions generally consist in sternocleidomastoid and subhyoid muscle hemorrhages. Traumatic ruptures of deep neck structures are rare. We report 2 cases of partial and complete ruptures of sternocleidomastoid muscles after suicidal hanging. Both were typical and complete hanging. In 1 case, muscle laceration was associated with common carotid rupture on the same side. Hemorrhage at the rupture site was only found at the microscopic level. Such injuries may result from the ligature's compression and depend on duration of suspension. Heavy body weight, rigid rope material, and fall after a jump may promote their occurrence.

Injury after non-judicial hanging

Hanging is an important and increasingly common method of suicide in developed countries. Little is known about the true human pathophysiological changes and injury patterns associated with hanging and near hanging. Cervical spine injury is commonly reported; however, there is a paucity of large data sets concerning this injury. This review article focuses on the incidence of cervical spine and associated neck injuries and their role in morbidity and mortality following non-judicial hanging. A total of 26 heterogeneous studies were identified examining injury after hanging or near hanging. In total, there were 2795 patients; 1530 (54.7%) with true hanging and 1265 (45.3%) with near hanging. Cervical spine injury was reported in a total of 58 (2.08%) patients. Injuries to the airway and vessels of the neck seem rare. This is somewhat lower than the current accepted incidence for cervical spine injury after hanging or blunt force trauma. The overall incidence of cervical spine injury after hanging is low. Spinal immobilisation should probably be instituted depending on the mechanism of the hanging. However, a patient presenting with signs of life to an emergency department is unlikely to have a severe cervical spine injury.

Fracture of the cricoid as a potential pointer to homicide. A 6-year retrospective study of neck structures fractures in hanging victims

The distinction of a suicidal hanging from a simulated hanging following a homicidal strangulation is highly challenging. The present study evaluates the fracture of the cricoid cartilage as a potential pointer toward homicide. Despite the numerous studies on neck structures fractures in hanging, this is the first study to concentrate on the cricoid cartilage. Neck structures fractures in all cases of suicidal hanging over a 6-year period were retrospectively reviewed (231 cases) and a comparison with homicidal hangings (4 cases) and homicidal no-hanging strangulations cases (52 cases) was performed. Overall, neck structures fractures were found in 23.4% of suicidal cases (54 cases). The cricoid cartilage was intact in all suicidal hangings. The general incidence of fractures in homicidal no-hanging strangulation was 65.4% (34 cases),with an incidence of fracture of the cricoid cartilage of 20.6%. By compiling studies from the literature, only one cricoid cartilage over 2700 suidical hanging cases was found, whereas an incidence of 5 to 20% is found for homicidal strangulation. It is therefore proposed that the presence of a fracture of the cricoid in an apparent suicidal hanging should be considered highly suspicious.