Material properties of human infant skull and suture at high rates

Clinicians are often faced with the challenging task of distinguishing between accidental and inflicted pediatric head trauma. There is currently a disparity in the anecdotal case study literature as to what kinds of injuries can occur in children from low height falls. There is also a paucity of material property data for pediatric skull and suture at rates similar to those expected in low height falls. We tested human infant (<1 year old) cranial bone and suture from 23 calveria in three-point bending and tension, respectively, at rates ranging from 1.2-2.8 m/sec. Donor age was found to have the largest influence on the elastic modulus and ultimate stress of cranial bone, with an increase in age increasing both material properties. In adults, cranial bone and suture have similar properties and the adult calveria deforms very little prior to fracture. In contrast, pediatric cranial bone is 35 times stiffer than pediatric cranial suture. In addition, pediatric cranial suture deforms 30 times more before failure than pediatric cranial bone and 243 times more than adult cranial bone. The large strains in the pediatric bone and suture result in a skullcase that can undergo dramatic shape changes before fracture, potentially causing substantial deformation in the brain. The sizeable difference between pediatric bone and suture material properties also underscores the crucial role that sutures play in the unique response of the pediatric head to impact in low height falls. These data provide necessary information to enhance our understanding of mechanisms of head injury in young children.     

Evaluation of Skull Cortical Thickness Changes With Age and Sex From Computed Tomography Scans

Head injuries resulting from motor vehicle crashes (MVC) are extremely common, yet the details of the mechanism of injury remain to be well characterized. Skull deformation is believed to be a contributing factor to some types of traumatic brain injury (TBI). Understanding biomechanical contributors to skull deformation would provide further insight into the mechanism of head injury resulting from blunt trauma. In particular, skull thickness is thought be a very important factor governing deformation of the skull and its propensity for fracture. Previously, age‐ and sex‐based skull cortical thickness changes were difficult to evaluate based on the need for cadaveric skulls. In this cross‐sectional study, skull thickness changes with age and sex have been evaluated at homologous locations using a validated cortical density‐based algorithm to accurately quantify cortical thickness from 123 high‐resolution clinical computed tomography (CT) scans. The flat bones of the skull have a sandwich structure; therefore, skull thickness was evaluated for the inner and outer tables as well the full thickness. General trends indicated an increase in the full skull thickness, mostly attributed to an increase in the thickness of the diploic layer; however, these trends were not found to be statistically significant. There was a significant relationship between cortical thinning and age for both tables of the frontal, occipital, and parietal bones ranging between a 36% and 60% decrease from ages 20 to 100 years in females, whereas males exhibited no significant changes. Understanding how cortical and full skull thickness changes with age from a wide range of subjects can have implications in improving the biofidelity of age‐ and sex‐specific finite element models and therefore aid in the prediction and understanding of TBI from impact and blast injuries. © 2015 American Society for Bone and Mineral Research.     

Bitemporal head crush injuries: clinical and radiological features of a distinctive type of head injury

OBJECT: Most craniocerebral injuries are caused by mechanisms of acceleration and/or deceleration. Traumatic injuries following progressive compression to the head are certainly unusual. The authors reviewed clinical and radiological features in a series of patients who had sustained a special type of cranial crush injury produced by the bilateral application of rather static forces to the temporal region. Their aim was to define the characteristic clinical features in this group of patients and to assess the mechanisms involved in the production of the cranial injuries and those of the associated cerebral and endocrine lesions found in this peculiar type of head injury. METHODS: Clinical records of 11 patients were analyzed with regard to the state of consciousness, cranial nerve involvement, findings on neuroimaging studies, endocrine symptoms, and outcome. Furthermore, an experimental model of bitemporal crush injury was developed by compressing a dried skull with a carpenter's vice. Seven of the 11 patients were 16 years old or younger. All patients presented with a characteristic clinical picture consisting of no loss of consciousness (six patients), epistaxis (nine patients), otorrhagia (11 patients), peripheral paralysis of the sixth and/or seventh cranial nerves (10 patients), hearing loss (five patients), skull base fractures (11 patients), pneumocephalus (11 patients), and diabetes insipidus (seven patients). Ten patients survived the injury and most recovered neurological function. CONCLUSIONS: Static forces applied to the head in a transverse axis produce fractures in the skull base that cross the midline structures without producing significant cerebral damage. Stretching of cranial nerves at the skull base explains the nearly universal finding of paralysis of these structures, whereas an increase in the vertical diameter of the skull accounts for the occurrence of diabetes insipidus in the presence of an intact function of the anterior pituitary lobe. The association of clinical, endocrine, and neuroimaging findings encountered in this peculiar type of head injury supports the idea that this subset of injured patients has a distinctive clinical condition, namely the syndrome of bitemporal crush injury to the head.     

Multidisciplinary management of a traumatic posterior meningeal artery pseudoaneurysm: A case report and review of the literature

BackgroundMeningeal arterial injuries represent <1% of all blunt traumatic brain injuries (TBIs). Middle meningeal artery (MMA) lesions comprise the majority. However, there is little clinical data on posterior meningeal artery (PMA) injuries.Case reportA 69-year-old man was brought to our trauma center after sustaining a fall inside a warehouse. He was GCS (Glasgow Coma Scale) 3 on arrival. Non-contrast CT (computed tomography) brain showed subarachnoid hemorrhage with diffuse cerebral edema and a basilar skull fracture. The patient subsequently underwent emergency ventriculostomy. Immediately after the procedure, further imaging with CTA (computed tomography angiography) head identified a hyperintense posterior cranial fossa lesion, prompting cerebral angiography with identification and embolization of a traumatic PMA pseudoaneurysm. The patient improved and was discharged to a long-term acute care facility. At 3 months post-discharge, the patient was eating, talking with family, and working aggressively with physical therapy.DiscussionThis case represents a functional neurologic outcome from a rare subset of TBI. Early CTA head imaging is not supported by limited literature, but allowed for expedient identification and definitive management of this PMA pseudoaneurysm. In the critical care setting, hyperosmolar therapy, CSF (cerebrospinal fluid) drainage, prompt enteral nutritional support, and early tracheostomy all represent evolving evidence-based strategies to optimize care for severe TBI.ConclusionsThe initial evaluation and management of severe TBI can be nuanced. Future research may refine indications for CTA head to the diagnostic evaluation of patients with both severe TBI and skull fractures.     

Contrecoup fractures of the anterior cranial fossae as a consequence of blunt force caused by a fall

Summary Contrecoup fractures of the base of the skull are regarded as rare in the clinical literature.In our material (n=171 falls on the same level and on or from stairs), the overall frequency of contrecoup fractures of the anterior cranial fossa in fatal cranio-cerebral trauma due to falls was 12%, as compared to 24% with occipital point of impact of the head.The relationships between the impact site on the head, form of fracture at the point of impact with involvement of the skull cap and/or the base of the skull, coup and contrecoup injuries of the brain, localization of contrecoup fractures in the anterior cranial fossa and the occurrence of monocle and spectacle haematomas display a major variability.Fractures occur in the form of simple fractures and as impression fractures (fracture fragments or fracture boundaries displaced to the inside).Clinical diagnosis is difficult because of the concealed position of the anterior skull base.Contrecoup fractures become of forensic medical significance when symptoms of a frontobasal injury occur for the first time after trauma which has occured some time in the past and when the question arises as to the causal connection with the original trauma.In investigation of living persons, it may be difficult to decide whether haemorrhages in the region of the orbit and its vicinity result from a direct blunt force or derive from fractures of the base of the skull, especially contrecoup fractures.     

Plasma levels of procalcitonin and neopterin in multiple trauma patients with or without brain injury

Clinical and experimental evidence suggests that traumatic brain injury (TBI) leads to a systemic immune response. To examine whether TBI causes a release of procalcitonin (PCT) or neopterin (NT) into the circulation, we compared plasmatic mediator levels among multiple injured patients with or without TBI. In total, 98 trauma patients (24 with TBI only, 39 with extracranial injuries excluding TBI, and 35 with combined injuries) and 35 healthy volunteers were studied. Blood was sampled at 15 predefined time points within 132 h after injury and analysed for NT and PCT. Multivariate statistical comparisons were adjusted for different severity of head, thorax, abdomen and extremity injuries, as quantified by the Abbreviated Injury Scale (AIS). PCT was normal 3 h after trauma, but 24 h after extracranial injuries a massive release (median 3 ng/mL) was observed. Significant positive associations between injury severity and posttraumatic PCT levels were found for abdominal and extremity, but not for cranial or thoracic injuries. Only modest changes of marginal statistical significance were detected for NT. The maximum increase per AIS point was 9% (95% confidence intervals [CI]: 3-16%). The effect of TBI on NT release was significant only at 108 h posttrauma with a 5% (95% CI: 1-10%) increase per AIS point. TBI induces a release of PCT and NT into the plasma, but this effect seems to be smaller for intra- than for extracranial injuries, probably due to more extensive surgery for abdominal and extremity injuries.     

Blunt versus penetrating violent traumatic brain injury: frequency and factors associated with secondary conditions and complications

OBJECTIVE: To compare types and frequency of medical complications and comorbidities associated with violence-related penetrating traumatic brain injury (TBI) as compared to violence-related blunt TBI. METHOD: Data were collected prospectively at four medical centers participating in the TBI Model Systems (TBIMS) of Care project. A total of 317 individuals met the inclusion criteria for the TBIMS (i.e., showed evidence of a TBI, were age 16 or older, presented to the TBIMS emergency department within 24 hours of injury, and received acute and rehabilitation services within the model system). MAIN OUTCOME MEASURES: Frequency of medical complications and comorbid diseases. RESULTS: Patients with penetrating injuries suffered significantly higher rates of respiratory failure (P =.004), pneumonitis/pneumonia, (P =.002), skull fracture (P =.001), cerebrospinal fluid leak (P =.0005), and hypotonia (P =.001) than did patients with blunt injuries. Prediction of complications and comorbidities via multiple regression revealed that a penetrating violent injury and the severity of injury were independent predictors of a higher rate of medical complications, whereas age and gender did not account for unique variance in the equation. CONCLUSIONS: Penetrating injuries are associated with higher rates of certain medical complications, especially to the pulmonary and central nervous systems. Acute care physicians and physiatrists must be prepared to treat these complications more often in patients with penetrating injuries.     

An investigation of cranial motion through a review of biomechanically based skull deformation literature

ObjectivesThere is ongoing debate over the existence of cranial motion resulting from manual manipulation during Cranial Osteopathy (CO). The purpose of this study was to review and summarize the literature regarding cranial mobility and human cranial stiffness in order to evaluate the validity of cranial movement in humans due to manual manipulation.MethodsIn Part I, the literature was reviewed to determine the existence and extent of cranial motion in animals and humans. In Part II, the literature was reviewed to determine the stiffness of the human cranium. In Part III, a biomechanical analysis was performed to determine the amount of force necessary to cause cranial deflections reported in the studies identified in Part I, using published skull stiffness values reported in the studies identified in Part II.ResultsSkull deflection across the cranial sutures of animals ranged from 0 μm to 910 μm. Cranial vault deflection in living humans was reported to range from 0.78 μm to 3.72 μm. Reported human skull stiffness values ranged from 390 N/mm to 6430 N/mm depending on the region of the skull and the method of loading. Based on the range of skull stiffness values, it was determined that an applied force between 0.44 N and 23.2 N would be required to cause 0.78 μm of deflection, and between 2.09 N and 111 N would be required to cause 3.72 μm of deflection.ConclusionExternally applied forces and increases in intracranial pressure can result in measurable cranial motion across the cranial sutures in adolescent and adult mammalian animal species, and measurable changes in cranial vault diameter in post-mortem and living adult humans. However, the amount of cranial motion may vary by subject, the region of the head to which forces are applied, and the method of force application. Given that the forces required to generate reported cranial deflections in living humans are within the range of forces likely to be used during CO, it is reasonable that small amounts of cranial deflection can occur as a result of the forces applied to the skull during CO.     

Significance of shock in head-injured patients with skull fracture

The clinical differences between patients with skull base and convexity fractures were retrospectively investigated in 324 patients, of whom 110 had suffered head injury resulting in skull fracture. These 110 patients were divided into the skull base and convexity groups. There were no significant differences between the groups with respect to sex, age, Glasgow Coma Scales, injury severity scores, pupil abnormalities, and outcomes. Automobile collisions were the most common causes in the skull base group, and falls in the convexity group. Traumatic Coma Data Bank diffuse 1 type injuries were more frequent in the skull base group and evacuated masses were more frequent in the convexity group. Multiple injuries, shock on admission, lower hemoglobin concentrations, and increased transfusion requirements were evident in the skull base group. Controlling for shock, the outcomes in the skull base group were favorable. Convexity fractures were usually associated with isolated severe head injuries and require brain protection therapy. Skull base fractures were caused by a significant force distributed over a large area of the body with a tendency to induce shock, and require a multidisciplinary approach to treatment.     

Management of Minor Head Injuries: Admission Criteria, Radiological Evaluation and Treatment of Complications

Summary The clincal course of patients admitted following minor head injuries (Glasgow Coma Score [GCS] 13–15) has been studied less extensively than in severely head injured patients. Admission criteria, methods and indications for radiological evaluation are controversial. To study this further, a retrospective review of 633 patients admitted following such injuries to King Khalid University Hospital between 1986 and 1993 was undertaken. Their ages ranged from one month to 80 years (average 17 years). The mechanisms of injury were mainly falls in 339 (53.5%) cases and road traffic accidents in 234 (37%). None of the cases resulted from a non-accidental injury. Radiological evaluation was by skull radiography in 616 (97.3%) cases followed by CT scan in 131 (20.7%). These studies revealed a skull fracture in 78 (12.7%) cases. Six of these 78 patients with skull fracture required a neurosurgical procedure during the first week post injury. These represented 0.97% of the cases who had skull radiographs. A base of skull fracture was an ominous sign, since 3 of the 5 cases with such fractures required ventilation of which one resulted in the only mortality of this series, the fourth developed meningitis. Of the cases studied, 3 (0.5%) developed growing skull fractures all had the initial injury during their first year of life. Other complications were as follows: 25 (3.9%) early post-traumatic seizures, 10 (1.6%) chronic subdural haematomas, 9 (1.4%) extradural haematomas, 2 (0.3%) post-traumatic hydrocephalus and one (0.2%) cerebral abscess. We conclude that patients who have an abnormal GCS, a neurological deficit, post-traumatic seizure, signs or suspicion of basal or depressed skull fracture should be admitted for observation because of the risk of deterioration. Patients with a history of loss of consciousness or amnesia without any of the previous may be discharged to be observed at home by a competent observer, otherwise, will need admission for observation. Radiological evaluation once indicated must be by CT scan. There is no benefit from immediate skull radiography in the initial evaluation of minor head injuries. The indications for CT are an abnormal GCS, presence of neurological deficit, signs of basilar or depressed fracture and persistent or progressive headache or vomiting. Infants with minor injuries should be followed up at least once after two to three months for possible growing fractures.     

Do Concomitant Cranium and Axis Injuries Predict Worse Outcome? A Trauma Database Quantitative Analysis

We performed a trauma database analysis to identify the effect of concomitant cranial injuries on outcome in patients with fractures of the axis. We identified patients with axis fractures over a 14-year period. A binary outcome measure was used. Univariate and multiple logistic regression analysis were performed. There were 259 cases with axis fractures. Closed head injury was noted in 57% and skull base trauma in 14%. Death occurred in 17 cases (6%). Seventy-two percent had good outcome. Presence of abnormal computed tomography head findings, skull base fractures, and visceral injury was significantly associated with poor outcome. Skull base injury in association with fractures of the axis is a significant independent predictor of worse outcomes, irrespective of the severity of the head injury. We propose that presence of concomitant cranial and upper vertebral injuries require careful evaluation in view of the associated poor prognosis.     

Blast-induced biomechanical loading of the rat: an experimental and anatomically accurate computational blast injury model

Abstract Blast waves generated by improvised explosive devices (IEDs) cause traumatic brain injury (TBI) in soldiers and civilians. In vivo animal models that use shock tubes are extensively used in laboratories to simulate field conditions, to identify mechanisms of injury, and to develop injury thresholds. In this article, we place rats in different locations along the length of the shock tube (i.e., inside, outside, and near the exit), to examine the role of animal placement location (APL) in the biomechanical load experienced by the animal. We found that the biomechanical load on the brain and internal organs in the thoracic cavity (lungs and heart) varied significantly depending on the APL. When the specimen is positioned outside, organs in the thoracic cavity experience a higher pressure for a longer duration, in contrast to APL inside the shock tube. This in turn will possibly alter the injury type, severity, and lethality. We found that the optimal APL is where the Friedlander waveform is first formed inside the shock tube. Once the optimal APL was determined, the effect of the incident blast intensity on the surface and intracranial pressure was measured and analyzed. Noticeably, surface and intracranial pressure increases linearly with the incident peak overpressures, though surface pressures are significantly higher than the other two. Further, we developed and validated an anatomically accurate finite element model of the rat head. With this model, we determined that the main pathway of pressure transmission to the brain was through the skull and not through the snout; however, the snout plays a secondary role in diffracting the incoming blast wave towards the skull.     

Bitemporal compression injury caused by static loading mechanism. Report of two cases

The authors report two cases of bitemporal compression injury caused by a static loading mechanism. These head injuries resulted from gradual bitemporal compression of the head. Plain skull films showed multiple skull fractures, and carotid angiography revealed internal carotid artery obstruction at the base of the skull. Neurological examination disclosed a slight disturbance of consciousness, hemiparesis, multiple cranial nerve injuries, and Horner's syndrome. In comparison with impact head injury, the energy from this type of trauma tends to be transmitted to the foramina and hiati of the middle cranial fossa and results in multiple injuries to the cranial nerves, sympathetic nerves, and blood vessels.     

Collet-Sicard syndrome resulting from closed head injury: case report

A 67-year-old man developed paralysis of the right ninth, tenth, eleventh, and twelfth cranial nerves (Collet-Sicard syndrome) after sustaining a closed head injury. Plain x-ray films of the skull revealed two linear fractures of the occipital bone (one of them probably traversing through the right occipital condyle) and a prominent soft-tissue shadow in the region of the nasopharynx, suggestive of a skull base fracture. The patient was managed conservatively. This is the only case of unilateral multiple caudal cranial nerve palsies (IX through XII), seen by us over a 20-year period, from among more than 5,000 moderate to significant head injuries.     

Head injuries in skiers: an analysis of injury severity and outcome

To examine the incidence, injury severity, and outcomes of persons hospitalized as a result of ski-related head trauma, a cross-sectional survey was carried out from the Colorado traumatic brain injury database. This database is an ongoing population-based statewise surveillance system, compiled by the Department of Public Health and Environment. Participants were Colorado residents who sustained a head injury while skiing at Colorado ski resorts and hospitalized over three full ski seasons (1994-1997). Injury severity measures included GCS, ISS, AIS, and presence/absence of intracranial lesion, skull fracture and amnesia. Outcome measures included GOS and hospital length of stay. Mean injury severity scores were as follows: GCS 14.51 (SD=0.99), AIS 2.98 (0.99) and ISS 13.17 (6.71). Twenty-four per cent sustained skull fracture, 39% had intracranial lesions, and 79% demonstrated amnesia. Mean length of stay was 4.31 days (10.58). Head injury incidence was 0.77 per 100 000 ski visits (agespecific range=0.17-1.91). Males were more likely to have a skull fracture and evidence of intracranial lesion. Finally, children and older adults were at increased risk of ski-related head trauma, suggesting head injury prevention programmes geared toward these age groups should be emphasized.     

Factors influencing posttraumatic seizures in children

The ideal treatment of children with head trauma would include prevention of posttraumatic seizures. Ninety-two of 937 children with head injuries (9.8%) experienced posttraumatic seizures. In 94.5% of these patients (87 of 92), seizures developed within the first 24 hours after injury. Three children convulsed between 24 hours and 7 days, but only 2 children developed seizures after the 1st week. Factors found to influence the likelihood of seizures included severe head injury (GCS, 3 to 8), diffuse cerebral edema, and acute subdural hematoma (P less than 0.001). Seizures occurred in 35% of severely head-injured children compared to 5.1% with minor head injury (P less than 0.001). A less significant correlation (P less than 0.1) was noted between seizures and open, depressed skull fractures. We found no significant correlation between seizure occurrence and numerous other factors including age, sex, fracture location and type (other than open, depressed fractures), parenchymal injuries, fixed neurological deficits, and cranial operation. Based on our observations, we recommend the prophylactic use of anticonvulsants in children at higher risk for posttraumatic seizures: those with diffuse cerebral edema, acute subdural hematoma, open, depressed skull fracture with parenchymal damage, or severe head injury (GCS less than or equal to 8).     

钛合金板置入在颅骨缺损修复中的应用

目的:探讨钛合金板置入在颅骨缺损修复中的应用。方法:对12例颅骨缺损的患者先进行三维CT检查,设计个性化的钛合金板置入以修复颅骨缺损。结果:本组患者均愈合良好,无感染、钛板外露及头皮血运障碍,避免了再次手术。结论:应用钛合金板修复颅骨缺损,具有良好的生物学力度,抗击性强,并发症少,生物相容性好等优点,可获得较好的治疗效果。     

Management of head injury. The skull and meninges.

Injuries to the skull and meninges frequently occur concomitantly with head trauma. Controversies over the operative versus nonoperative management of depressed skull fractures, frontal sinus fractures, cerebrospinal fluid leaks, and cranial nerve injuries are discussed in this article.