篩骨胞を温存した前頭洞開放に影響する解剖構造についての検討

The procedure for endoscopic frontal sinusotomy via the route anterior to the ethmoid bulla（intact bulla frontal sinusotomy［IBFS］）is safe and of educational importance. IBFS is not possible in all cases; therefore, we examined the factors affecting the success rate of IBFS. We examined 65 sides to investigate whether the following items might affect the success rate of IBFS:（1）variation in the number of anterior ethmoid cells,（2）presence of frontal sinus lesion,（3）variations of the superior attachment of the uncinate process,（4）anteroposterior diameter of the agger nasi cell（ANC）, （5）distance between the agger nasi and the frontal sinus drainage pathway（FSDP）,（6）anteroposterior diameter（AP diameter）of the frontal recess, and（7）other factors（sex, age, pathophysiology of sinusitis, presence of nasal polyps in middle meatus）. The success rate of IBFS was 52%（11/21）in cases with a supra bulla frontal cell（SBFC）and 93%（41 /44）in those without a SBFC（p＝0.0003）. The success rate of IBFS was 73%（36/49）in the presence of lesions in the FSDP and 100%（16/16）in the absence of lesions in the FSDP（p＝0.027）. Other investigated factors had no effect on the IBFS success rate. Thus, the most important factors that affected the success of IBFS were the presence of the SBFC and lesions in the FSDP.