Applied anatomy of the anterior cranial fossa: what can fracture patterns tell us?

Traumatic Brain Injury: A Comprehensive Review of Biomechanics and Molecular Pathophysiology

Traumatic brain injury (TBI) is a critical public health concern with profound consequences for affected individuals. This comprehensive literature review delves into TBI intricacies, encompassing primary injury biomechanics and the molecular pathophysiology of the secondary injury cascade. Primary TBI involves a complex interplay of forces, including impact loading, blast overpressure, and impulsive loading, leading to diverse injury patterns. These forces can be categorized into inertial (e.g., rotational acceleration causing focal and diffuse injuries) and contact forces (primarily causing focal injuries like skull fractures). Understanding their interactions is crucial for effective injury management. The secondary injury cascade in TBI comprises multifaceted molecular and cellular responses, including altered ion concentrations, dysfunctional neurotransmitter networks, oxidative stress, and cellular energy disturbances. These disruptions impair synaptic function, neurotransmission, and neuroplasticity, resulting in cognitive and behavioral deficits. Moreover, neuroinflammatory responses play a pivotal role in exacerbating damage. As we endeavor to bridge the knowledge gap between biomechanics and molecular pathophysiology, further research is imperative to unravel the nuanced interplay between mechanical forces and their consequences at the molecular and cellular levels, ultimately guiding the development of targeted therapeutic strategies to mitigate the debilitating effects of TBI. In this study, we aim to provide a concise review of the bridge between biomechanical processes causing primary injury and the ensuing molecular pathophysiology of secondary injury, while detailing the subsequent clinical course for this patient population. This knowledge is crucial for advancing our understanding of TBI and developing effective interventions to improve outcomes for those affected.

Mathematical analysis of fracture configuration in predicting outcome in complex anterior skull base trauma

Craniofacial trauma involving the anterior skull base produces a heterogenous injury with variance in fracture pattern, complexity and outcome. Variance is influenced by the biomechanical properties of the craniofacial construct and by the magnitude and vector of the impacting energy. Fractal dimension and other metrics applied to individual fracture patterns allows quantification of fracture complexity and severity, which can be used to correlate with neurological outcome. Frontobasal fractures from 81 patients admitted to two UK major trauma centres were analysed. Patients were divided into two groups: those with anteriorly-based vectors of impact and those with laterally-based vectors. Osseous disruption was quantified by: fractal dimension, fracture length, number of termini, and number of nodes, and then compared with neurological outcome using first recorded Glasgow Coma Score (GCS), and requirement for intubation. As fracture length increased, fractures from anterior impacts became more complex and reticulated compared with lateral impacts; fractal dimension also increased more rapidly for anterior impacts. Longer fracture length in both groups was associated with a significantly lower GCS, and increased requirement for intubation (p < 0.001 and p < 0.001 respectively). Fracture propagation and severity of head injury was different in anterior-directed trauma compared to lateral-directed trauma. Consequently, we suggest that the central region of the anterior skull base acts to primarily absorb impact force thereby behaving as a protective ' crumple zone ' . In severe mechanisms the protective mechanism is exceeded and the fracture length tended to that of the lateral group worsening prognosis.

Anterior Cranial Base Reconstruction in Complex Craniomaxillofacial Trauma: An Algorithmic Approach and Single-Surgeon's Experience

Management of traumatic skull base fractures and associated complications pose a unique reconstructive challenge. The goals of skull base reconstruction include structural support for the brain and orbit, separation of the central nervous system from the aerodigestive tract, volume to decrease dead space, and restoration of the three-dimensional appearance of the face and cranium with bone and soft tissues. An open bicoronal approach is the most commonly used technique for craniofacial disassembly of the bifrontal region, with evacuation of intracranial hemorrhage and dural repair performed prior to reconstruction. Depending on the defect size and underlying patient and operative factors, reconstruction may involve bony reconstruction using autografts, allografts, or prosthetics in addition to soft tissue reconstruction using vascularized local or distant tissues. The vast majority of traumatic anterior cranial fossa (ACF) injuries resulting in smaller defects of the cranial base itself can be successfully reconstructed using local pedicled pericranial or galeal flaps. Compared with historical nonvascularized ACF reconstructive options, vascularized reconstruction using pericranial and/or galeal flaps has decreased the rate of cerebrospinal fluid (CSF) leak from 25 to 6.5%. We review the existing literature on this uncommon entity and present our case series of n  = 6 patients undergoing traumatic reconstruction of the ACF at an urban Level 1 trauma center from 2016 to 2018. There were no postoperative CSF leaks, mucoceles, episodes of meningitis, or deaths during the study follow-up period. In conclusion, use of pericranial, galeal, and free flaps, as indicated, can provide reliable and durable reconstruction of a wide variety of injuries.