The Japan Neurotrauma Data Bank (JNTDB) Project 2015 study was conducted from April 2015 to March 2017 in 1,345 registered traumatic brain injury patients. Thirty two emergency medical centers took part in the study. Patients with severe head injury were eligible for entry with a Glasgow Coma Scale score of 8 or less at admission. Patients who underwent craniotomy were also included. Data entry form with 175 items were created originally from multi–factorial views. The results show that the patients with severe traumatic brain injury in Japan are aging rapidly. However the outcome of patients had almost unchanged, because of ag­gressive treatments. After this, the data of JNTDB P2015 should be analyzed from various points of view. We have to post about the appropriate ap­proach of treatment for the geriatric traumatic brain injury patients prior to the other developed countries.

Background and purpose: Trend of trepanation as an optional surgical procedure was investigated in cases with severe traumatic brain injury (TBI), by comparing data from Japan Neurotrauma Data Bank (JNTDB) Project 2015 with those from Project 2009.

Materials and Methods: Two–hundred and thirty cases with severe TBI, who were initially treated by trepanation, were involved in this study (M:F = 133:97, Age 67±20 y.o.). In these cases, following parameters were summarized from JNTDB Project 2015 database, to compare with those of 2009; age, gender, cause of trauma, Glasgow Coma Scale (GCS) scores on admission, worst GCS scores, presence of mydriasis, CT findings (intracranial hematoma thickness, width of midline shift, and appearance of ambient cistern), Glasgow Outcome Scale (GOS) scores on discharge. Correlation between preoperative clinical parameters and GOS scores were also examined in cases with acute subdural hematoma (ASDH), in particular.

Results: There was no significant difference in gender, age, cause of TBI, distribution of targeted intracranial hematoma, and GCS scores between Project 2015 and 2009. Mydriasis were presented bilaterally in 66 (29%), unilaterally in 37 (16%), and not in 125 (54%) in Project 2015. Compared to Project 2009, bilateral mydriasis was significantly decreased in Project 2015, as normal pupil reaction was significantly increased. In appearance on CT, ambient cistern appeared normal in 44 (19%), unilaterally compressed in 110 (48%), and disappeared in 76 (33%) in Project 2015. Compared to Project 2009, disappeared ambient cistern was significantly decreased, as normal and unilateral compression was significantly increased in Project 2015. Thickness of midline shift was significantly decreased in Project 2015 than 2009. Intracranial hematoma thickness was significantly larger in Project 2015 than 2009, in contrast. GOS scores were GR in 8 (3%), MD in 31 (14%), SD in 57 (25%), VS in 30 (13%), and D in 103 (45%). Mortality was significantly decreased in Project 2015 than 2009, although favorable outcome (GR+MD) was not significantly different between them. In Project 2015, a combination of GCS score 3 and bilateral mydriasis, or disappearance of ambient cistern on CT could correctly expect mortality in cases with ASDH, as well as Project 2009.

Conclusion: Emergency trepanation is widely used in cases with severe TBI in Japan. Recent decrease in mortality may be brought by avoiding trepanation in cases who presented with a couple or more of brain herniation signs.

Objectives: The purpose of this study was to elucidate the recent trends in temperature management for severe traumatic brain injury (TBI) using the database of the Japan Neurotrauma Data Bank (JNTDB) Project 2015.

Methods: Data from JNTDB Project 2015, in which a total of 1,345 patients registered, were retrospectively reviewed. Patients were classified into three groups: hypothermia (targeted body temperature of < 35°C), inten­sive normothermia (35.5 – 38.0°C), and no temperature management. Clinical characteristics, radiological findings, methods of temperature management and the clinical course of each group were examined.

Results: Forty patients (3.0%) were categorized into the hypothermia group, 335 patients (24.9%) into the intensive normothermia group and 970 (72.1%) into the no temperature management group. The mean ages of the groups were 42.8 years, 53.5 years and 61.3 years respectively (p<0.0001). Traffic accidents were the most common cause of injury in the hypothermia group compared with the other groups (p=0.0002). In the hypothermia group, the Glasgow Coma Scale sum score tended to be lower (p=0.0565), pupillary abnormality and tachypnea were more frequent (p=0.0225 and p=0.0044 respectively) and systolic blood pres­sure was higher (p=0.002). Intracranial pressure (ICP) was more fre­quent­ly monitored as 95% (p<0.0001) and initial ICP (21.2 mmHg) and maximum ICP (40.2 mmHg) tended to be higher (p=0.0782 and p=0.0929 respectively). Evacuated mass lesions according to the Traumatic Coma Data Bank CT classification was more commonly involved in the hypo­thermia group (p=0.0242). Cooling blankets were most frequently used for temperature management, followed by cooling pads and intravascular cooling systems. The time to reach the maximum ICP was significantly extended in the hypothermia group (p=0.0402). There were no differences in favorable outcome rates between the groups.

Conclusion: Hypothermia treatment was more commonly applied to younger traffic accident victims with evacuated mass lesions under ICP monitoring. This finding corresponded with the results of recent random­ized clinical trials concerning hypothermia for TBI.

Introduction: Protocols for sedative drugs in patients with severe head traumatic brain injury have not been established. The purpose of this study was to investigate sedatives based on target temperature man­age­ment (TTM).

Subjects and Methods: Data from 1345 patients were obtained from the Japan Neurotrauma Data Bank Project 2015, a cohort observational study. Patients with non–active treatment at trauma resuscitation, cardiac arrest, or no medical treatment were excluded, leaving 787 patients in this study. The use of neuro–intensive drugs including sedatives, analgesic and neuromuscular blocking drugs (NMBDs) in adults and children was examined. The patients were divided into three groups: (1) the non–temperature control (NC) group treated with no TTM; (2) the aggressive normothermia therapy (NT) group treated with aggressive normothermia group; and (3) the mild hypothermia therapy (HT) group with mild hypothermia management. We compared the sedatives, analgesia, and NMBDs in the three groups.

Results: For sedatives, propofol (PROP) was often used in 45% in adults. Midazolam (MDZ) and dexmedetomidine (DEX) are more commonly used in pediatric compared with adult patients (p<0.001, 0.04). Two or more sedatives were administered in 15% of adults and 12% pediatric patients. In adults, DEX was often administered in the NT group, and MDZ in the HT group. Analgesics was used in 53% of NT and 73% of HT patients. NMBDs were used for 10% of NT and 40% of HT patients.

Conclusion: Currently, neuro–intensive care such as TTM that is based on the pathological condition has become common, and it is necessary to also show the optimal protocol in for sedative management of severe traumatic brain injuries.

Recent traffic accident statistics have reported a decrease in the number of accidents. As the new project 2015 of the Japan Neurotrauma Data Bank (JNTDB) has been tabulated, the trend of severe head injury associated with recent traffic accidents was examined in comparison with previous projects.

The survey was conducted in the 24 months between 2015 and 2017. We examined severe head injury of Glasgow Coma Scale (GCS) score 8 or less at the age of 6 years or older at the time of injury. The number of target cases is 832 for p1998, 797 for p2004, 753 for p2009, and 924 for p2015. We examined the proportion of traffic trauma cases, the condition of the victim, the age, the drinking condition, the means of transportation, the transportation time, the neurological evaluation, the physiological evalu­ation, the first CT findings, and the outcome at discharge. Furthermore, some examinations are divided into age groups (A group: under 45 years, B group: 45 to 64 years, C group: 65 to 74 years, D group: 75 years or more) and comparison about age group changes was added.

The proportion of traffic injuries among registered cases decreased to 64.7% in p1998, 53.8% in p2004, and 43.2% in p2009, but turned to 44.7% in p2015. The number of traffic injuries per institution decreased to 17.9 for p1998, 11.3 for p2004, 7.4 for p2009, and 6.5 for p2015 for one year. By age group, it turned from p2009 in D group and from p2015 in C group, and while the aging progressed, the decreasing trend tended to converge. The injury situation was the lowest in the four–wheeled vehicle, the accident while riding on a motorcycle at p2015, and the accident while walking increased mainly to the elderly. The drinking situation was slightly reduced in p2015 compared to p2009. The driver’s seat belt use decreased slightly from p2009 to 37.0% in p2015. The helmet wear also decreased to 45.0% in p2015. The possibility of reduc­tion of the case by improvement of the safety device is also considered. Transportation by helicopter and doctor car increased to 17.9% together, and there was an increase in the chances for medical workers to get in touch with the sick persons at an early stage. There was no significant difference between systolic blood pressure and PaO2 and GCS at the hospital arrival, and the ISS temporarily deteriorated at p2009 was alleviated at p2015. CT findings showed that diffuse injury charact­er­istical­ly decreased in group D. The outcome at discharge was not signifi­cantly changed in GR and MD, and the increase in SD and VS and the decrease in D were recognized as significant differences compared to p1998. By age group, good prognosis group (GR + MD) tends to improve outcome in group A. Mortality decreases in the C and D groups, and an increase in the poor prognosis group (SD + VS) is an issue for the future.

Objective: In this study we described the clinical characteristics and prognosis in multiple trauma concomitant with severe traumatic brain injury(sTBI), and also revealed the differences of fibrinolytic activity between each combinations of extra–cranial injuries.

Design and setting: This is a retrospective observational study using data derived from Japan Neurotrauma Data Bank (JNTDB) project 2015 (p2015), a nationwide multi–institutional registry project. JNTDB regis­tered patients with traumatic brain injuries having Glasgow Coma Scale score ≤8 at admission and/or undergoing craniotomy ⁄ trephination.

Patients and methods: Total 1,345 cases were registered with p2015 from 32 institutions in Japan. Of them, this study enrolled those having brain injuries with Abbreviated injury scale (AIS) ≥3 and being transported to hospital within 3 hrs of injury. We excluded those whose D–dimer (DD) ⁄ Fibrinogen (Fib) value were unavailable. We divided these patients into two group. M group defined as sTBI with one or more AIS≥3 injuries in the face, chest, abdomen, and AIS≥4 in the pelvis ⁄ extremities. The others were S group. We described patient’s informa­tion, mechanisms of injury, primary input subjects such as vital signs, DD ⁄ Fib value and prognosis at discharge in each group. And we also described the differences between each pattern of injury combination using M group.

Results: 172 patients enrolled to M group (31.9%). The median DD (µg/ml) ⁄ Fib (mg/dl) value was 59.4 ⁄ 207.5 in M group, 31.7 ⁄ 242.5 in S group. The in–hospital mortality was 34.9% in M group, 33.2% in S group. Among M group, in patients with abdominal injury, average DD value was higher than 70 µg/ml and average Fib value was lower than 200 mg/dl. The most frequent concomitant extra–cranial injury was chest injury alone.

Conclusions: In sTBI cases, with or without extra–cranial severe injuries, DD value was high and hyperfibrinolysis had occurred. Especially with abdominal injury and pelvic injury, DD value was elevated higher that worsened prognosis. We should be aware of these features of multiple trauma concomitant with sTBI and need to make proper treatment strategies.

In some patients with severe head injury, a mild condition on arrival may be deteriorated in the acute phase, leading to a severe status. By analyzing Project 2015 (P2015) in the Japan Neurotrauma Data Bank (JNTDB), we investigated the course and characteristics of patients in whom the condition deteriorated in the acute phase. In this study, we report on the comparison with the previous Project 2009 (P2009).

The subjects were patients with GCS 9 or higher at the time of admission to hospital.

We compared the outcomes of patients with deterioration in the acute phase (deteriorated group) and those with early operation (operated group). The deteriorated group was 263 cases and the operated group was 107 cases. The favorable outcome was 50.2% in the deteriorated group and 70.1% in the operated group, and there was a significant difference between the two groups.

The mean time from the initial CT to the worst CT in minor cases of the deteriorated group was 6.1 hours for the favorable outcome group and 12.6 hours for the poor outcome group, with a significant difference between the two groups. In this study, the outcome of the minor cases in deteriorated group was worse than the result previous P2009. This result may be related to the extension in time from the initial CT to the worst CT.

We compared factors between the deteriorated group and the operated group. The significant difference between the two groups was the proportion of pedestrians in traffic accidents, Talk and Deteriorate (T&D), and CT findings with subarachnoid hemor­rhage. The factors that were significantly different in this study are the same as in the previous P2009 analysis. Therefore, it is considered to be an important factor as deteriorated factors.

Background: In Japan, the number of geriatric traumatic brain injury (TBI) cases is increasing because of aging in the Japanese population. Decision–making in the treatment of elderly patients involves various aspects. This study aimed to determine the strong predictors for non–aggressive (non–A) treatment at initial visit in cases of severe TBI.

Method: This is a multicenter, prospective observational study. Of the 1,345 cases registered in the Japan Neurotrauma Data Bank (JNTDB) Project 2015, we analyzed the cases of 1,034 patients (mean age, 58 ± 25 years), and excluded cases with missing laboratory data. A decision tree was developed to identify the combination of factors with the highest statistical power to predict the decision–making. The following eight factors were selected: age, body tem­perature, respiratory rate, oxygen saturation, Glasgow coma scale score, pupil findings, patency of the basal cisterns on head computed tomography (CT) scan, and D–dimer levels. Logistic regression analyses were performed to identify the factors associated with the decision for non–A treatment.

Results: Of the 1,034 patients, aggressive (A) treatment was selected in 887 patients (85.8%), and non–A treatment in 147 patients (14.2%). The decision for non–A treatment was strongly related to three factors: age at the time of injury (A; 57±25 years, non–A; 69±21 years), pupil dilatation (A; n=152 [17%], non–A; n=72 [49%]), and absence of basal cisterns on head CT scan (A; n=181 [20%], non–A; n=75 [51%]) (P<0.01). The cut–off value of patients’ age relative to the univariate analysis was 76 years. The receiver operating characteristic curve value of this factor was 0.83.

Conclusions: Among the cases registered in JNTDB2015, patient’s age was the strong predicting factor for decision–making for non–A treatment. This finding strongly reflects the characteristics of an aging society.

Purpose: The number of cases of severe head injury caused by traffic accident due to 4 wheel vehicle in Japan is decreasing. But there are still many cases. We report about severe head injury caused by traffic accident in the Japan Neurotrauma Data Bank 2015 (JNTDB2015).

Subjects and Methods: The 428 cases of the traffic accident caused by 4 wheel vehicle in the JNTDB2015 were examined. Those were divided into 4 groups: pedestrian (P), bicycle (B), motorcycle (M), 4 wheel vehicle (V). We analyze patient’s characteristics: age, sex, Glasgow Coma Scale (GCS) at the arrival, Injury Severity Score (ISS) and CT classification at the first time, safety device: helmet, seat belt and air bag and outcomes at 6 months after traffic accident.

Results: The registered cases were 184 (P), 95 (B), 106 (M) and 43 (V). The median age were 69 (P), 62 (B), 40.5 (M) and 36 (V). Pedestrian group was older than any other groups. And bicycle group was older than M and V. The median ISS were 29 (P), 25 (B), 25.5 (M) and 35 (V). The median ISS of B was lower than P and V. CT classification (diffuse injury (DI) / focal brain injury (FBI)) were 84/100 P, 39/56 B, 60/46 M and 33/10 V. 4 wheel vehicle group included more DI than any other groups. The rate of wearing helmet was 3.94% (B), 72.7% (M). The rate of fastening seatbelt was 78.6% at driver’s seat, 80.0% at passenger seat, and 16.7% at back seat. Outcome of pedestrian at 6 months after traffic accident was worse than M and V.

Conclusion: We reported about clinical feature and outcome of severe head injury caused by traffic accident due to 4 wheel vehicle. There are still many cases of severe head injury caused by traffic accident. The continuation of the investigation is necessary.

Purpose: Head injury is a major cause of death among children. To clarify ways of decreasing preventable deaths, data from Japan Neurotrauma Data Bank (JNTDB) Project 2015 were analyzed and compared with data from Project 2009.

Subjects and Methods: Project 2009 covered patients with severe head injury and a Glasgow Coma Scale (GCS) score ≤8, patients with talk and deteriorate, and patients who underwent surgery for traumatic intracranial lesions in 2015–2017 In total, 91 patients ≤15 years of age were included. We analyzed age, cause of injury, duration of transfer, time of patient transfer, GCS score, papillary abnormality, body temperature, serum glucose, Injury Severity Score (ISS), skull fracture, computed tomography (CT) findings (as classified by Traumatic Coma Data Bank criteria), main lesion of focal brain injury on CT, other lesions on CT, treatment, and outcome at discharge.

Results: Factors associated with poor outcome of pediatric severe head injury were GCS at admission ≤8, Body temperature at admission <37℃, patient with intraventricular hemorrhage (IVH) on CT, patient with traumatic subarachnoid hemorrhage (SAH) on CT and blood data of D–dimer at admission.

Conclusion: We analyzed 91 patients with pediatric severe head injury. To understand the characteristics of pediatric severe head injury in Japan, further studies are needed.

This study documents the epidemiology of severe head injury in Japan based on the projects conducted by Japan Neurotrauma Data Bank Committee. Four projects, named as Project 1998, 2004, 2009, and 2015, were completed so far to compare the age distribution of patients, cause of head injury, pathophysiology, and outcome among projects. In Project 2015, 1) the average age of patients was getting older over the projects, 2) the peak occurrence of severe head injury shifted to older than 80 years, 3) the rate of elderly pedestrian injury increased in traffic accidents, 4) falling on the ground increased as a cause of injury, 5) mortality rate increased with age, as well as prior projects. In conclusion, these epidemiological data will help us to prevent severe head injury in the future.

Objective: Recently, with the development of computing equipment, analysis methods for big data have changed from conventional methods, and machine learning such as deep learning is attracting attention. We performed factor analysis related to survival based on the data of Japan Neurotrauma Data Bank Project 2015 (JNTDB P2015).

Methods: Of 1345 cases registered in the JNTDB P2015, 534 cases which full data collected were enrolled in this study. The factors using analysis were revealed short time in patients arrived at hospital. Analysis were performed with logistic regression, decision tree, and random forest.

Results: Logistic regression, decision tree and random forest analysis: accuracy rate were 92.6%, 78.7% and 88.6%, precision rate were 91.4%, 84.7%, and 92.0%, recall rate were 93.6%, 75.6%, and 86.1%. Each analysis receiver operation characteristic (ROC) curve and area under the curve (AUC) were 0.94, 0.89 and 0.98. Almost predicts value were same with each analysis, but in decision tree analysis the ICP monitoring was an important feature.

Conclusion: Using the data of JNTDB P2015, we examined prognostic factors by machine learning in addition to the logistic regression analysis used conventionally. We extracted feature quantities that could not be extracted by conventional analysis, and extracted factors that determine the prognosis with complex factors. Among them, ICP monitoring was an important feature of decision tree.

In the present study, bicycle accidents among the cases registered in Project 2015 (P2015) of the Japan Neurotrauma Data Bank were analyzed. From among 1,346 cases of severe head injuries registered in P2015, 123 related to bicycle accidents were extracted. Age, Glasgow Coma Scale (GCS) score at admission, type of injury, Injury Severity Score (ISS), Glasgow Outcome Scale score (GOS) at discharge, and helmet use were analyzed. An outcome analysis was performed for each item. As a result, the age distribution between younger and older cases showed a bimodal pattern.

In addition, 64 cases of acute subdural hematoma and 25 cases of epidural hematoma were identified. Regarding outcomes based on the GCS classification, the good outcome group (G) included the good recovery and moderate disability groups, and the poor outcome group (P) included the severe disability, vegetative state, and dead groups.

In comparison, the outcome was 42 cases in the G group and 81 cases in the P group. In the P group, the ratios of acute subdural and epidural hematomas among all cases were 48/64 (75.0%) and 9/25 (36.0%), respectively. In addition, 24 cases involved young people <19 years of age. Among these cases, 17 (70.8%) were in the G group and seven (29.2%) were in the P group. On the other hand, 99 cases involved adults (20–99 years old) and 47 involved older adults (≥70 years old). Among the patients ≥70 years of age, eight (17.0%) were in the G group and 39 (83.0%) were in the P group. Many of the traffic accidents involved four–wheel vehicles. Only two cases had clearly been wearing a helmet. The poor outcomes seen among those aged ≥70 years may be related to the effects of trauma and the presence or absence of antiplatelet medication before injury. However, it is difficult to clarify the usefulness of helmets because very few cases were wearing one. Therefore, additional case series need to be analyzed in the future.

Objective: We investigated recent situation of targeted temperature management (TTM) and assessed usefulness of TTM of severe TBI from the data of the Project 2015 (P2015) in the Japan Neurotrauma Data Bank.

Methods: This is a cohort observational study of a nationwide prospective registry between April 2015 and March 2017. Among registered patients, those with a Glasgow Coma Scale (GCS) score of 9 or more and a GCS score of 3 with bilateral nonreactive pupils, and those with only epidural hematoma in CT scan, and not underwent radical treatment were excluded. First, the implementation rate of TTM in P2015 was compared to that of P2009. Second, the patients were divided into the two groups: the TTM group and the control group not underwent TTM. Using propen­sity score matching, the unfavorable outcome and mortality of the TTM group were compared to the control group.

Results: Of 1,345 registered patients, 552 adult severe TBI patients were included. The implementation rate of hypothermia in P2015 was significantly lower than that in P2009 (3% vs. 13%); however, the implementation rate of normothermia in P2015 was higher than that in P2009 (34% vs. 29%). In the propensity score matching analysis, 100 patients of the TTM group were matched to 100 patients of the control group, and there was no significant difference of unfavorable outcome (57% vs. 63%, p=0.39) and mortality (34% vs. 39%, p=0.46) between the TTM group and the control group. In the subgroup analyses, the TTM group demonstrated a significant reduction of unfavorable out­come compared with the control group in patients with surgical removal for intracranial hematomas (65.5% vs. 83.6%, p=0.03).

Conclusion: Among severe TBI patients with surgical removal of for intracranial hematomas, TTM improved neurological outcome at 6 months. TTM including intensive normothermia is consid­ered as a treatment option in neurointensive care for severe TBI.

Background: Seizures are recognized as an important complication of traumatic brain injury (TBI). However, post–traumatic seizures and –epilepsy, –convulsions are complicated in their terms. We analyzed present situation of post–traumatic seizures from the data of the Project 2015 in the Japan Neurotrauma Data Bank (JNTDB2015).

Patients and methods: 1,344 patients were included in this study. Seizure was observed in 139 patients (10.3%). Seizure happened within 24 hours after the trauma in 51 patients (3.8%), within a week in 52 patients (3.9%).

Results: A risk factor of post–traumatic seizures is the presence of evacuated mass lesion on CT image (p<0.05) in this study. Antiepileptic drugs (AED) are used in 363 patients (27%). AEDs were used in 128 patients (96%) of patients with seizures, and were used in 236 patients (19.5%) of patients without seizures. No relationship was observed between the outcome of patients and the pres­ence of post–traumatic seizures.

Discussion and conclusion: We analyzed post–traumatic seizures using JNTDB 2015. Post–traumatic seizure was ob­served in 10% patients. However, AEDs were rarely used despite of the recommendation by guideline. Furthermore, electroencephalogram examination rate was very low. As the prevention and treatment of seizures are important issues in the management of severe head trauma, we should plan the prospective multicenter studies for the standardization of the treatment strategy in our society. In addition, it will be necessary to review the evaluation items for the future databank projects.

Many patients are unable to recover completely their social function follow­ing head trauma caused by traffic accidents. Prediction on occur­rence of higher brain dys­function is important for those who will be able to return home after head trauma. In this study we tried to reproduce injury condition in cases with traumatic higher brain dysfunction caused by traffic accidents and discussed the relationship between the mecha­nical impact to brain and higher brain dysfunction. We reproduced 6 cases using combination of multi­body analysis and finite element (FE) head modeling. As a result, the strain on the frontal lobe caused by an injury condition was suggested to contribute to the onset of attention disturbance during the chronic phase of treatment. This method has the possibility to predict the onset and severity of traumatic higher brain dys­function.

Background: Severe traumatic brain injury is the most common cause of traumatic death. The average age of the population of Japan is increasing and according to the Japan Neurotrauma Data Bank, the number of older patients with severe traumatic brain injuries is also increasing.

Materials and Methods: Awaji Island is home to approximately 130,000 individuals who are, on average, older than residents of other regions in Japan, with approximately 35% of the population considered elderly. Hyogo Prefectural Awaji Medical Center, a major hospital on Awaji Island, treats almost all patients with severe traumatic brain injury on the island. We retrospectively examined the ages, mechanisms of injury, blood test results, surgical procedures, hospitalization complications, and prognoses in 72 patients with severe traumatic brain injuries who were treated at our hospital from 2014 to 2018.

Results: Compared with those in the Japan Neurotrauma Data Bank cohort, the ratios of age to fall injuries were significantly higher in our cohort (p=0.029, p=0.014). The age distribution of our cohort featured a single peak in the eighth decade of life. During multivariate analysis of factors related to favorable prognosis, low D–dimer and age were significant prognostic factors (p=0.033, p=0.045). In elderly people older than 75 years, the prognoses were mostly poor; however, a good prognosis was observed in six cases (16.7%). Prompt treatment was administered in these cases and relatively minor injuries were observed. Seven elderly individuals (19.4％) fell on the job or were involved in a motor vehicle accident; these individuals exhibited a poor prognosis.

Conclusion: Our study revealed a higher number of elderly individuals with severe traumatic brain injuries compared to that in a recent study. As with the previous study, elderly patients in our study exhibited a poor prognosis. However, since some elderly patients had a good prognosis, immediate treatment was considered particularly important and potentially life–saving. Additionally, elderly individuals with severe head injuries were more likely to have sustained falls to the ground, and falls on the job and injuries while driving were also observed. Since severe injuries generally relate to poor prognosis, preventative medical and administrative measures should be the focus.

Reversible lesions of the splenium of the corpus callosum have been reported in patients with a variety of diseases and conditions. However, the distinct etiology of the lesion remains uncertain. Herein, we report a case of reversible lesion of the splenium of the corpus callosum presenting with prolonged disturbance of consciousness following traumatic brain injury.

A 20–year–old man who was hit with a blunt instrument was admitted. The GCS was 6 upon admis­sion. Head CT showed a depressed left parietal bone fracture with a brain contusion and a traumatic brain hemorrhage in right cerebellar hemisphere. The disturbance of consciousness was persistent. Seven days later, brain MRI showed high signal intensity on diffusion–weighted image in the splenium of the corpus callosum, whereas the apparent diffusion coefficient value was decreased in the same lesion. Three weeks after the initial brain MRI, follow–up brain MRI showed complete resolution of the previously–observed restricted diffusion lesion in the splenium of the corpus callosum. One month after onset, the level of consciousness was improved to GCS 14.

Reversible lesion of the splenium of the corpus callosum can occur following traumatic brain injury and lead to prolonged disturbance of consciousness.