頭部外傷データバンクにおける急性硬膜下血腫526例の検討―局所性およびびまん性脳損傷としての病態生理

Acute Subdural Hematoma Associated with Diffuse Brain Injury: Analysis of 526 Cases in Japan Neurotrauma Data Bank

Ⅰ．はじめに

　急性硬膜下血腫（ASDH）の死亡率は，診断技術，医療機器の進歩，救急体制の発達にもかかわらず，過去40年間50～60％と高率であることは周知の事実である^5,6,9-11)．ASDHは，局所性脳損傷（focal brain injury：FBI）としての血腫と脳実質損傷に伴う脳腫脹の2つが存在するため，その病態は複雑である．

　日本神経外傷学会は，1997年に「頭部外傷データバンク検討委員会」を発足させ，1998年より頭部外傷データバンク（Japan Neurotrauma Data Bank：JNTDB）として，わが国で全国規模の臨床的多施設共同研究を開始した．JNTDBでは，従来と異なり，重症頭部外傷の病態をFBI単独例，DBI（diffuse brain injury）単独例, FBIとDBIの合併例に分類してる^3,7,8)．本研究では，JNTDB 1,002例におけるASDH症例をFBI単独例およびDBI合併例に分類し，その病態を分析することを目的とした．

　OBJECTIVE　Traumatic acute subdural hematomas (ASDH) in Japan Neurotrauma Data Bank were categorized into focal brain injury (FBI) group and diffuse brain injury (DBI) group, and were analyzed to clarify the pathophysiological and therapeutic aspects of these injuries.

　METHODS　Data in Japan Neurotrauma Data Bank were reviewed for 1,002 severely head-injured patients treated at hospitals between 1998 and 2001; 526 of these patients had ASDH. ASDH in this data bank were categorized into FBI group and DBI group on the findings of CT scan. The clinical variables in these injuries were evaluated.

　RESULTS　Of 526 patients with ASDH, 246 (46.8%) were categorized into FBI group, 280 (53.2%) were DBI group. The patients with DBI group were younger, injured in traffic accident, lower Glasgow Coma Scale (GCS), higher Injury Severity Score, poorer outcome, compared to those with FBI group. The patients in DBI group, who underwent decompressive craniectomy and craniotomy, had a significantly better outcome than those who underwent hematoma evacuation via burr hole. There were no relationship between the time from injury to operation and outcome in the patients with DBI group, whereas patients with early surgery in FBI group showed significantly poorer outcome. Hypothermia and the placement of intracranial pressure monitor improved outcome only in patients of DBI group.

　CONCLUSION　It seems that the pathophysiological and therapeutic aspects of ASDH associated with DBI might differ from that with FBI alone.