A new grading system for evaluation of technical difficultyof aneurysm treatments. Presentation of the system and a four year experience of its application to ruptured aneurysms.

SUMMARY: We introduced our grading system that enablesus to objectively evaluate the degree of technical difficulty of aneurysm treatment modalities, i.e. neck clipping and coil embolization.The characteristics of our grading system were that the difficulty of each treatment was indicated on a ten point scale obtained by adding the scores for various technical factors. We studied annual change of treatments selected for ruptured aneurysms and the treatment results at our institute. In the earlier half of the study period, neck clipping was more frequently selected despite the fact that the difficulty score of coil embolization was lower than that of neck clipping. However, in the later half, the treatment modality was selected in accordance with the difficulty score in most of the cases. As a result, there was a tendency for the proportion of mRS 0 to increaseand that of mRS 6 to decrease as the years passed. Our grading system may be useful in objectively selecting a more appropriate treatment, and further improve treatment results.