脳動脈瘤破裂くも膜下出血におけるSEP測定の意義について  [in Japanese] Measurement of Somatosensory Evoked Potentials in Aneurysmal Subarachnoid Hemorrhage  [in Japanese]

くも膜下出血(SAH)の急性期には, 出血による激しい頭蓋内圧の変動, 出血後の各種ラジカルによる脳損傷の進展, それに伴う虚血性変化などさまざまな変化が頭蓋内で嵐のように生じている. このように複雑な病態の管理においては, 脳の生理学的モニターは不可欠と考えられるが, そのひとつに体性感覚誘発電位(somato-sensory evoked potential, SEP)がある. SEPは, ベッドサイドでできる簡便な検査で, 頭部外傷から神経変性疾患にいたる多種多彩な神経疾患の病態評価に用いられている. 著者らも, 頭部外傷や脳内出血で, 脳機能のモニターとして活用し, その有用性を報告している. ここでは, 急性期SAHにおける, SSEP(short latency somato-sensory evoked potential)測定の臨床的意義について報告する. 対象, 方法 対象は, 脳動脈瘤破裂によるSAH例で, SSEPを施行しえた102例である. 入院時の重症度は, WFNS分類で, GI;30例, GII;21例, GIII;18例, GIV;13例, GV;20例である.

We evaluated the role of short-latency somatosensory evoked potentials (SSEP) in aneurysmal subarachnoid hemorrhage (SAH). In this retrospective study, we investigated 102 patients recording SSEP within 24 hours of SAH, including 30 patients in Grade I, 21 in Grade II, 18 in Grade III, 13 in Grade IV and 20 in Grade V on W.F.N.S. Scale. SSEP patterns in patients with SAH were ranked from I to V according to the central conduction time (CCT), the time between the Nl4 peak (recorded at C-2) and the N20 peak (recorded at the cortex) in response to median nerve stimulation on either affected or unaffected side. Outcome was determined according to Glasgow outcome scale. The prognostic value of SSEP was statistically confirmed (p value = 0.007). In particular the pessimistic prognosis was accurately predicted by poor SSEP grade, although optimistic prognoses could not necessarily be predicted by a good SSEP grade. Successive recording of SSEP showed that the CCT in the patients with symptomatic delayed vasospasm tended to prolong even in the early period as well as the CCT prolonged with developing delayed vasospasm. SSEP was a useful clinical indicator of aneurysmal SAH.