The evening seminar entitled “Basic science of Neurotrauma” in the 32nd annual meeting of the Japan Society of Neurotraumatology was reviewed and discussed future strategy of treatment and prevention of the neurotrauma in this article. Fourteen original papers were presented in the sym­po­sium regarding basic mechanisms and treatment in traumatic brain injury, cerebral ischemia and spinal cord injury. The studies for treatment of the neural injury have been suc­cessfully developing because of the development of several kinds of drug therapy, and the way to manipulate genes that expresses following neuronal injury by means of inhibition of apoptosis cascades with preconditioning paradigm. Furthermore, neural regeneration strategies have been expects to facilitate functional recovery after injury. Preconditioning approach against neural injury also exhibit similar effect to expansion of the secondary injury. Accumulating evidences these neuroprotective and helpful for regenerating injured brain is a new platform to study the neuro-regeneration, potentially protect against expansion of secondary injury from injury, and design strategies for prevent and recover from neurotrauma.

The effect of Diazepam, a benzodiazepine derivative, on post-traumatic neuronal hyperactivity in hippocampal CA1 was studied 7 days after lateral fluid percussion injury (FPI) in rats. In bilateral hippocampal CA1 areas, FPI enhanced excitatory synaptic responses but not presynaptic action potentials. We further evaluated the effect of Diazepam administered 30 and 90 minutes or 4 and 5 hours after FPI. The administration of Diazepam 30 and 90 min after FPI attenuated post-traumatic hyperexcitability. These findings suggest that administration of Diazepam early in the post-traumatic period suppresses FPI-induced hyperexcitability in the hippocampal CA1 neurons of rats.

Epidural hematoma (EDH) is most often caused by trauma. EDH occurs most frequently in young people following high-speed accidents. CT scanning is the diagnostic method of choice.

Craniotomy provides the most definitive form of surgical treatment of EDH. Recent guidelines have recommended evacuation of EDH for lesions greater than 30 ml in volume, and that any patient with an EDH and coma (GCS < 9) or anisocoria undergo evacuation as emergently as possible.

Craniotomy for evacuation of EDH mandates identification and elimination of the source of bleeding, via cauterization of vessels, waxing of bone sources. Dural sinus lacerations must sometimes be repaired, plugged, or tamponaded. Epidural tack-up sutures are placed in the perimeter and the center of the craniotomy, to prevent subsequent reaccumulation of blood in the epidural space. Bone flaps may usually be replaced due to frequent absence of underlying lesions and edema. Fractures may need to be repaired.

Mortality in the surgical subset of EDH patients has been reported around 5%. Functional outcome and mortality are affected by the following clinical findings: age, neurological status, time to evacuation, intracranial pressure elevations, and medical complications. CT findings affecting outcome from EDH include: hematoma volume, degree of midline shift, compressing of isterns, associated intracranial lesions, signs of active bleeding (heterogeneous density), presence of a skull fractures across a meningial artery, vein, or dural sunus.

The new surgical strategy of emergency burr hole (Bh) surgery followed by large decompressive craniectomy (LDC) was pro­posed for the treatment of an acute subdural hematoma (ASDH) of complicated hematoma type in 1994 in Japan. The purpose of this study was to identify patient selection criteria and outcome for adult patients with an ASDH undergoing emergency Bh surgery, and to define the state of the art of this strategy.

We reviewed surgically treated 552 adult patients with an ASDH enrolled in Japan Neurotrauma Data Bank Project 1998 and Project 2004. The mean age of patients was 58 years (range, 16 – 98 years; > 65 years, 41%) and the mean GCS was 6.4 (range, 3 – 15; 3 – 5, 51%). Three surgical procedures were performed: Bh surgery alone (=Bha) in 134 patients, Bh surgery followed by craniotomy or LDC (=Bhc) in 30, and craniotomy or LDC as a primary procedure (=Crt) in 388.

Patients with a GCS score of 3 – 5 and those showing dilated fixed pupil(s) or systemic shock on admission were more frequently underwent emergency Bh surgery than did those not revealing them. The proportion of the Bhc to the Bh (=% Bhc/Bh) was lowest in patients over the age of 65 years com­pared to other younger age groups (p=0.021). The % Bhc/Bh in each GCS group (GCS 3 – 5, 6 – 8, 9 – 15) was 17%, 27%, and 0% respectively (not significant). The mortality and the percent of favorable outcome related to type of operation in subgroups with a GCS score of 3 – 5 were as follows: Bha = 89% / 1% ; Bhc = 45% / 5%; Crt = 54% / 14%. Of 115 cases with favorable outcome 10 cases were underwent Bh surgery (Bha = 8, Bhc = 2). Clinical characteristics of them were a younger age (mean = 33.2 years; unfavorable, 60.0, p<0.001), a higher GCS score (mean = 6.6; unfavorable, 4.6, p=0.002) and low incidence of dilated fixed pupil(s) (40%; unfavorable, 75%, p=0.026).

Emergency Bh surgery is undoubtedly effective for patients with an ASDH of simple hematoma type. The new strategy has provided little improvement in outcome of patients with an ASDH of complicated hematoma type. Nevertheless, with appropriate modifications, this strategy will improve outcome after severe ASDH.

Purpose: In delayed cranioplasty using autogenous bone graft after external cranial decompression, postoperative infection, bone absorption and lysis are problematic. Various methods to preserve autogenous bone grafts have been reported, but no consensus has been reached. In our institution, cranioplasty was conventionally conducted using autogenous bone graft which were boiled and autoclaved after being preserved in ethanol (conventional method). However, we experienced a number of cases in which infection occurred as complications. Therefore, we have been conducting cranioplasty using autogenous bone grafts preserved at –80˚C (deep-freeze method) since 2005. In this report, we compared both methods from the viewpoints of the occurrence of infection and bone absorption.

Subjects and Methods: The subjects were 56 patients who underwent external cranial decompression at our hospital between January 1997 and June 2008. In the conventional method, autogenous bone grafts were preserved in 77% ethanol (4˚C), boiled for 20 – 60 minutes, and autoclaved before cranioplasty was conducted. In the deep-freeze method, autogenous bone grafts were preserved at –80˚C, and thawed naturally before cranioplasty was conducted. The conventional and deep-freeze methods were used in 45 and 11 cases, respectively.

Results: With the conventional method, infectious complications occurred in 11 cases (22.4%), and the removal of infected bone was necessary. There were cases in which marked bone absorption was observed. With the deep-freeze method, no infectious complications were observed. Up to the present, bone absorption has not been observed (observation period: 8 – 38 months).

Conclusion: It was suggested that cryopreservation at –80˚C is a favorable preservation method for autogenous bone grafts after external cranial decompression, in terms of the prevention of infection and bone absorption. However, the number of subjects was small and most of them have been observed for a short period; thereafter, further investigation is required.

Objectives: Baseball has one of the highest impact injury rates of any sport. Therefore, this study aimed to characterize the clinical features of head injuries resulting from being hit by a baseball.

Methods: The study included 12 patients hospitalized in our institute between January 2003 and July 2009. Eleven patients were boys (15 – 17 years old) who were members of high school baseball clubs and 1 patient was a 16 year-old girl who was hit by a baseball while playing another sport on the same field.

Results: Impact sites were temporal and temporooccipital regions in 5 cases, frontal to frontotemporal regions in 3 cases, occipital regions in 3 cases, and the face in 1 case. The most common fracture site was the frontal bone region (n=3). Intracranial injuries were detected on computed tomographic (CT) scans in 8 cases, including cerebral contusions in 7 cases, epidural hematomas in 2 cases, subdural hematomas in 4 cases, traumatic subarachnoid hemorrhage in 1 case, and pneumocephalus in 2 cases. In 4 of 7 patients with cerebral contusions, the impact site was in the temporal region. Among these 4 cases, 3 did not have skull fractures, suggesting that the mechanism of intracranial injuries was cavitation by inbending and outbending of the skull. On CT scans, most cases showed contusional changes accompanied by epi- or subdural hematomas as coup injuries. Only 3 cases showed transient neurological deficits on admission. No case required surgery. Although the majority of patients followed neurologically satisfactory courses, 1 suffered persistent seizures and another refused to attend school for 1 year after the accident due to depression.

Conclusions: Clinical features of impact injuries resulting from being hit by a baseball sometimes include brain parenchymal contusions and/or hemorrhage with or without skull fractures. Baseball officials should develop strategies for reducing both the rate of accidents and the impact shock in order to protect young and growing brains. Further systemic epidemiologic investigations of baseball-related injuries in Japanese high schools are required.