Survey of intensive care of severely head injured patients in the United Kingdom.

OBJECTIVES--To study practice in intensive care of patients with severe head injury in neurosurgical referral centres in United Kingdom. DESIGN--Structured telephone interview of senior nursing staff in intensive care unit of adult neurosurgical referral centre. SETTING--39 intensive care units in hospitals that accepted acute head injuries for specialist neurosurgical management, identified from Medical Directory and information from professional bodies. MAIN OUTCOME MEASURES--Details of organisation and administration of intensive care and patterns of monitoring and treatment for patients admitted with severe head injury. RESULTS--Patients were managed in specialist neurosurgical intensive care units in 21 of the centres and in general intensive care units in 18. Their intensive care was coordinated by an anaesthetist in 25 units and by a neurosurgeon in 12. Annual case-load varied between units: 20 received > 100 patients, 12 received 50-100, and seven received 25-49. Monitoring and treatment varied considerably between centres. Invasive arterial pressure monitoring was used routinely in 36 units, but central venous pressure monitoring was routinely used in 24 and intracranial pressure was routinely monitored in only 19. Corticosteroids were used to treat intracranial hypertension in 19 units. Seventeen units routinely aimed for arterial carbon dioxide pressure of 3.3-4.0 kPa, and one unit still used severe hyperventilation to a pressure of < 3.3 kPa. CONCLUSION--The intensive care of patients with acute head injuries varied widely between the centres surveyed. Rationalisation of the intensive care of severe head injury with the production of widely accepted guidelines ought to improve the quality of care.     

Evaluation of Hyperventilation in Treatment of Head Injuries

Reduction of the partial pressure of carbon dioxide in the arterial blood by mechanical hyperventilation (Pco₂ 25-30 mm Hg; Po₂ 100-150 mm Hg) may be beneficial in cases of severe head injury. To evaluate its efficacy and establish prognostic guidelines intracranial pressure, radiocirculograms, and cerebrospinal fluid (C.S.F.) lactate levels were studied in 31 patients. In survivors intracranial pressure fell and cerebral blood flow improved with treatment. A C.S.F. lactate greater than 55 mg/100 ml was associated with a poor prognosis. Selection of patients was based on clinical judgement, and adults with signs of extensive brain damage were excluded. The importance of an adequate airway and resuscitation is stressed before a final decision is made. The object of treatment is to improve the quality of survival and the criteria measured may aid in the distinction between patients with a potential for good recovery and those capable only of a vegetative existence. Many associated factors as well as hypocapnia reduce intracranial pressure, and these are discussed. We believe that hyperventilation may improve some head injuries, and further study is indicated.     

Advances in the Understanding and Treatment of Head Injury

The author describes his personal involvement in head injury prevention and management over the past 40 years. He reviews the evolution of knowledge concerning the role of increased intracranial pressure, and considers the importance of cerebral vasoparalysis in the production of signs and symptoms following head injury, and the development of methods of recording intracranial pressure continuously, over hours and days.The development of an experimental compression model has led to a fuller understanding of edema of the brain and has provided a means of studying, by light and electron microscopy, the histological changes that result from edema. More recently, analyses of biochemical changes and disturbed membrane function have opened up a new avenue of potential treatment. Moreover, it is now clear that cerebral vascular dilatation and abrupt pressure increase can be produced in the monkey, in over 50% of cases, by lesions in the dorsomedial nucleus of the hypothalamus. Similar lesions may occur in the human and this suggests other therapeutic approaches. There is, then, a genuine hope of a breakthrough in the management of head injuries.     

Consequences of head size following trauma to the human head.

The objective of the present study was to evaluate whether variation of human head size results in different outcome regarding intracranial responses following a direct impact. Finite Element models representing different head sizes and with various element mesh densities were created. Frontal impacts towards padded surfaces as well as inertial loads were analyzed. The variation in intracranial stresses and intracranial pressures for different sizes of the geometry and for various element meshes were investigated. A significant correlation was found between experiment and simulation with regard to intracranial pressure characteristics. The maximal effective stresses in the brain increased more than a fourfold, from 3.6kPa for the smallest head size to 16.3kPa for the largest head size using the same acceleration impulse. When simulating a frontal impact towards a padding, the head injury criterion (HIC) value varies from the highest level of 2433 at a head mass of 2.34kg to the lowest level of 1376 at a head mass of 5.98kg, contradicting the increase in maximal intracranial stresses with head size. The conclusion is that the size dependence of the intracranial stresses associated with injury, is not predicted by the HIC. It is suggested that variations in head size should be considered when developing new head injury criteria.     

Avoidable factors contributing to death after head injury.

We reviewed 116 patients, known to have talked before dying after head injury, to discover factors which had contributed to death but which might have been avoided. All the patients were admitted to a neurosurgical unit and had a neuropathological post-mortem examination. One or more avoidable factors were identified in 86 patients (74%); an avoidable factor was judged certainly to have contributed to death in 63 patients (54%). The most common avoidable factor was delay in the treatment of an intracranial haematoma; others included poorly controlled epilepsy, meningitis, hypoxia, and hypotension. Changes in the management of patients with head injuries which reduce the incidence of avoidable factors should decrease mortality from this condition.     

An anatomically detailed and personalizable head injury model: Significance of brain and white matter tract morphological variability on strain

Finite element head (FE) models are important numerical tools to study head injuries and develop protection systems. The generation of anatomically accurate and subject-specific head models with conforming hexahedral meshes remains a significant challenge. The focus of this study is to present two developmental works: first, an anatomically detailed FE head model with conforming hexahedral meshes that has smooth interfaces between the brain and the cerebrospinal fluid, embedded with white matter (WM) fiber tracts; second, a morphing approach for subject-specific head model generation via a new hierarchical image registration pipeline integrating Demons and Dramms deformable registration algorithms. The performance of the head model is evaluated by comparing model predictions with experimental data of brain–skull relative motion, brain strain, and intracranial pressure. To demonstrate the applicability of the head model and the pipeline, six subject-specific head models of largely varying intracranial volume and shape are generated, incorporated with subject-specific WM fiber tracts. DICE similarity coefficients for cranial, brain mask, local brain regions, and lateral ventricles are calculated to evaluate personalization accuracy, demonstrating the efficiency of the pipeline in generating detailed subject-specific head models achieving satisfactory element quality without further mesh repairing. The six head models are then subjected to the same concussive loading to study the sensitivity of brain strain to inter-subject variability of the brain and WM fiber morphology. The simulation results show significant differences in maximum principal strain and axonal strain in local brain regions (one-way ANOVA test, p < 0.001), as well as their locations also vary among the subjects, demonstrating the need to further investigate the significance of subject-specific models. The techniques developed in this study may contribute to better evaluation of individual brain injury and the development of individualized head protection systems in the future. This study also contains general aspects the research community may find useful: on the use of experimental brain strain close to or at injury level for head model validation; the hierarchical image registration pipeline can be used to morph other head models, such as smoothed-voxel models.

     

Computerised tomography of acute traumatic intracranial haematoma: reliability of neurosurgeons' interpretations.

Two neurosurgeons concerned with the emergency management of patients with head injury correctly diagnosed the presence or absence of an acute intracranial haematoma in 97 scans that were presented to them without knowledge of the patients'' clinical details. There were no false-positives or false-negatives, although identification of the type of haematoma was not always possible. The impact of the EMI scan on patient management demands new approaches to the care of head injuries.     

Avoidable factors contributing to death of children with head injury.

OBJECTIVE--To assess the incidence of potentially avoidable complications contributing to death of children with head injuries. DESIGN--Retrospective review of children who died with head injuries from 1979 to 1986 from data of the Office of Population Censuses and Surveys, Hospital Activity Analyses, case notes, coroners'' records, and necropsy reports. SETTING--District general hospitals and two regional neurosurgical centres in Northern region. RESULTS--255 Children died from head injury in the region, the mortality being 5.3 per 100,000 children per year. Head injury was the single most important cause of death in children aged greater than 1 year, accounting for 15% of deaths in children aged 1-15 years and a quarter for those aged 5-15 years. 121 Potentially avoidable factors possibly or probably contributing to death occurred in 81 children (32%). Half the children (125) died before admission, 27 of whom (22%) had potentially avoidable factors possibly or probably contributing to death, and 130 died after admission, 54 of whom (42%) had 93 such factors, which included failure of diagnosis or delayed recognition of intracranial haemorrhage or associated injury, inadequate management of the airways, and poor management of the transfer between hospitals. IMPLICATIONS--Regions should revise urgently their guidelines for optimal management and indications for neurosurgical referral to include children with severe head injuries and audit their systems of care for all patients with head injuries.     

The Routine Use of Echoencephalography in the Diagnosis of Intracranial Masses

Ultrasonic echoes can be detected from interfaces within the body. This principle has been applied to the examination of the cranial contents by the procedure of echoencephalography. The presence of a unilateral intracranial mass was correctly predicted by this technique in 30 out of 33 cases. The method of examination is simple, harmless, painless and rapid. Its general adoption as an aid in diagnosis of intracranial lesions, particularly in acute head injuries, is recommended.     

A Novel Rat Model to Study the Role of Intracranial Pressure Modulation on Optic Neuropathies

Reduced intracranial pressure is considered a risk factor for glaucomatous optic neuropathies. All current data supporting intracranial pressure as a glaucoma risk factor comes from retrospective and prospective studies. Unfortunately, there are no relevant animal models for investigating this link experimentally. Here we report a novel rat model that can be used to study the role of intracranial pressure modulation on optic neuropathies. Stainless steel cannulae were inserted into the cisterna magna or the lateral ventricle of Sprague-Dawley and Brown Norway rats. The cannula was attached to a pressure transducer connected to a computer that recorded intracranial pressure in real-time. Intracranial pressure was modulated manually by adjusting the height of a column filled with artificial cerebrospinal fluid in relation to the animal’s head. After data collection the morphological appearance of the brain tissue was analyzed. Based on ease of surgery and ability to retain the cannula, Brown Norway rats with the cannula implanted in the lateral ventricle were selected for further studies. Baseline intracranial pressure for rats was 5.5±1.5 cm water (n=5). Lowering of the artificial cerebrospinal fluid column by 2 cm and 4 cm below head level reduced ICP to 3.7±1.0 cm water (n=5) and 1.5±0.6 cm water (n=4), a reduction of 33.0% and 72.7% below baseline. Raising the cerebrospinal fluid column by 4 cm increased ICP to 7.5±1.4 cm water (n=2) corresponding to a 38.3% increase in intracranial pressure. Histological studies confirmed correct cannula placement and indicated minimal invasive damage to brain tissues. Our data suggests that the intraventricular cannula model is a unique and viable model that can be used to study the effect of altered intracranial pressure on glaucomatous optic neuropathies.     

A new method for the early diagnosis of brain edema/brain swelling. An experimental study in rabbits

The aim of the present work is to develop a non-destructive, non-invasive technique for the early diagnosis of an oncoming brain edema based on the variation of vibration characteristics of the head system (i.e. eigenfrequency spectrum and modal damping). Besides the theoretical model that supports the basic principle, the proposed technique has been verified experimentally in animal tests. The advantage of such an approach is that the relative information is available well in advance an increase of intracranial pressure is detected. The uncontrolled intracranial hypertension is associated with increased mortality or vegetative state in head trauma. Traumatic lesions located on temporal lobe render particularly impeding the transtendorial herniation. From the medical point of view, intracranial pressure (ICP) monitoring represents an effective way for early consideration of neurological decompensation in various neurosurgical conditions particularly in the head-injured setting. However, the use of ICP monitoring is not an effective way of brain edema detection, since ICP increase very often causes irreversible problems to the patient's brain. Therefore, the determination of an earlier, less invasive and more sensitive indicator of the oncoming intracranial hypertension and of the impeding neurological deterioration is of profound importance.

The present work aims at experimental verification of both eigenfrequency shifting and modal damping increase of the spectral response of the head system of rabbits, wherever a mass increase in the content of cranial shell appears. The conducted analysis concludes that the eigenfrequency spectrum and its modal damping characteristics are sufficiently sensitive parameters in order to characterize mass increase in the cranial shell.

Therefore the combination of both the above parameters could be used with confidence for the early diagnosis of brain edema.     

A Study on the Finite Element Model for Head Injury in Facial Collision Accident

In order to predict and evaluate injury mechanism and biomechanical response of the facial impact on head injury in a crash accident. With the combined modern medical imaging technologies, namely computed tomography (CT) and magnetic resonance imaging (MRI), both geometric and finite element (FE) models for human head-neck with detailed cranio-facial structure were developed. The cadaveric head impact tests were conducted to validate the headneck finite element model. The intracranial pressure, skull dynamic response and skull-brain relative displacement of the whole head-neck model were compared with experimental data. Nine typical cases of facial traffic accidents were simulated, with the individual stress wave propagation paths to the intracranial contents through the facial and cranial skeleton being discussed thoroughly. Intracranial pressure, von Mises stress and shear stress distribution were achieved. It is proved that facial structure dissipates a large amount of impact energy to protect the brain in its most natural way. The propagation path and distribution of stress wave in the skull and brain determine the mechanism of brain impact injury, which provides a theoretic basis for the diagnosis, treatment and protection of craniocerebral injury caused by facial impact.     

重型颅脑损伤后颅内高压的治疗研究进展

重型颅脑损伤后颅内压增高预示着不良的神经功能预后和极高的死亡率,一直是临床治疗中的研究热点,可采取高渗性脱水,亚低温疗法,巴比妥昏迷治疗及外科手术干预等治疗措施控制颅内压。由于亚低温治疗会增加患者发生肺炎的风险,巴比妥类药物副作用较大,现均已少用。近来研究发现,监测颅内压、脑灌注压、脑组织氧分压并指导临床治疗,可降低死亡率与改善预后。也有研究发现去骨瓣减压术治疗顽固性颅内高压与神经功能预后较差有关。目前关于颅内高压治疗的最佳方案仍存在争议,未来还需根据患者病情,为其制定规范化与个体化的治疗方案,预防继发性颅脑损伤,降低颅内压。本文就近年来重型颅脑损伤后颅内高压的治疗进展进行阐述。     

Head injuries in childhood: a 2-year survey.

A retrospective study was conducted of the 880 children with head injuries consecutively admitted to the Children''s Hospital of Eastern Ontario in Ottawa from July 1976 to June 1978. It confirmed a boy:girl ratio of about 2:1, with a peak of 3.5:1 around 7 years of age. The largest number of head injuries was in children under 1 year of age. Injuries were most common in summer and spring, and most were caused by falls. The most common place for head injuries was in the home, but the single most common cause of injuries was bicycle accidents, which were responsible for 12% of all the head injuries. Skull fractures were found in 30% of all the patients. Of the 34 patients with severe head injuries 8 (24%) died, 9 (26%) had a moderate residual disability and 17 (50%) made a good recovery. There were no other deaths, so the mortality for the entire group of 880 patients was 0.9%.     

Radioimmunoassay of serum creatine kinase BB as index of brain damage after head injury.

Brain-type creatine kinase isoenzymes (CK-BB) was measured by radioimmunoassay in the serum of 54 patients with head injuries. CK-BB was not detectable in 476 out of 1006 controls, the remaining 530 normal samples containing a mean of 1.5 +/- SD0.75 microgram/l. The mean CK-BB concentrations in patients with mild, moderate, and fatal head injuries were all significantly higher than the control value (p < 0.01 in each instance). Patients with serious head injury had serum concentrations many times the normal value, in two cases within 30 minutes after impact. Fatally injured patients continued to have high serum concentrations several days after injury. In less serious cases values approached normal within two or three days. Every patient with evidence of cerebral laceration, bruising, or swelling had a serum CK-BB concentration above normal. Raised concentrations were found in 14 out of 22 patients with concussion only. The serum CK-BB concentration appears to be a sensitive index of brain damage and may prove useful in the management and follow-up of head-injured patients.     

Serious head injury in sport.

Of 1900 head injuries serious enough to be admitted to the neurosurgical unit in Glasgow over a five year period, 52 (2.7%) were due to "sport." Golf, horse-riding, and Association football were the sports most commonly linked with serious head injury. Golfing injuries were all compound depressed fractures, and all these patients made a good recovery; horse-riding produced more severe injuries, three of the eight patients being left with residual disability. Much attention has been directed to preventing repeated minor head injury in boxing, but this study emphasises the need for preventing both the primary head injury and secondary complications associated with other sports.     

Management of traumatic intracranial haematoma.

Deciding which head-injured patients should be transferred to a neurosurgical unit can be difficult. Traditional criteria emphasise the development of deteriorating responsiveness but lead to delayed diagnosis and to avoidable mortality and morbidity. To discover if a more liberal admission policy improved results a study was conducted analysing data collected prospectively from 683 patients who had a traumatic intracranial haematoma evacuated in the Glasgow neurosurgical unit between 1974 and 1980. In the first four years, before the change in policy, mortality was 38% but decreased to 29% afterwards. This reflected a reduction in the proportion of patients who talked after injury but who deteriorated into coma before operation--that is, 31% before the change in policy, 16% afterwards. If the potential benefits of CT scanning in the management of head injuries are to be realised patients must be scanned sooner than in the past. This will usually mean that more patients should go to a neurosurgical unit and that simple criteria for transfer should be established.     

A clinical study of the EMI scanner: implications for provision of neuroradiological services.

The records of the first 571 patients to be examined with an EMI brain scanner were assessed. The patients were divided into diagnostic categories according to their clinical presentation. The intracranial investigations that would have been performed had the scanner not been available were compared with the investigations that were actually performed. As expected, the number of contrast investigations fell, but the reduction surpassed expectation. If the full clinical impact of the scanner is to be realised the patient''s illness must be defined in detail and strict attention paid to radiographic detail. By reducing the number of special contrast investigations use of the scanner enables existing contrast facilities to serve a wider population; and use of the brain scanner in district general hospitals would improve the service to patients, especially those with head injuries.     

Intracranial pressure and intracranial volume in children with craniosynostosis.

Intracranial volume and intracranial pressure have been measured in 66 children with craniosynostosis, 48 boys and 18 girls. The premature fusion of skull sutures is assumed to restrict skull growth and predispose to elevated intracranial pressure. Thirteen children (20 percent) had raised intracranial pressure and demonstrated a significant restriction of skull growth. In this series, volume measurement alone, however, did not serve as a reliable predictor that the intracranial pressure was raised.     

Risk of Maltreatment-Related Injury: A Cross-Sectional Study of Children under Five Years Old Admitted to Hospital with a Head or Neck Injury or Fracture

Objectives

To determine the predictive value and sensitivity of demographic features and injuries (indicators) for maltreatment-related codes in hospital discharge records of children admitted with a head or neck injury or fracture.

Methods

Study design: Population-based, cross sectional study. Setting: NHS hospitals in England. Subjects: Children under five years old admitted acutely to hospital with head or neck injury or fracture. Data source: Hospital Episodes Statistics, 1997 to 2009. Main outcome measure: Maltreatment-related injury admissions, defined by ICD10 codes, were used to calculate for each indicator (demographic feature and/or type of injury): i) the predictive value (proportion of injury admissions that were maltreatment-related); ii) sensitivity (proportion of all maltreatment-related injury admissions with the indicator).

Results

Of 260,294 childhood admissions for fracture or head or neck injury, 3.2% (8,337) were maltreatment-related. With increasing age of the child, the predictive value for maltreatment-related injury declined but sensitivity increased. Half of the maltreatment-related admissions occurred in children older than one year, and 63% occurred in children with head injuries without fractures or intracranial injury.

Conclusions

Highly predictive injuries accounted for very few maltreatment-related admissions. Protocols that focus on high-risk injuries may miss the majority of maltreated children.