Radioanatomic study of the skull base and septum in Asians: implications for using the nasoseptal flap for anterior skull-base reconstruction.

BACKGROUND: The objective of this work was to assess the feasibility of using the nasoseptal flap (NSF) for covering the anterior skull-base defect in Asians, and to compare the results in whites.

METHODS: A retrospective radioanatomic analysis was conducted in 100 Korean adult patients. Septal and skull-base dimensions were measured and the feasibility of the NSF in reconstructing a full anterior skull-base defect was evaluated. Scans of 49 white patients were analyzed for a comparative study.

RESULTS: Among various septal dimensions, the length of the septum was significantly different in Koreans when compared to whites. Skull-base dimensions such as anterior skull-base length and width at the level of the anterior ethmoidal artery were different between the 2 ethnic groups. Individual differences between the anterior width of the hypothetical NSF and the anterior margin of the skull-base defect (2.8 ± 3.1 vs 6.4 ± 4.8) and the difference between the hypothetical NSF length and the length of the flap needed for full coverage of the defect were significantly smaller in Korean patients (7.2 ± 3.8 vs 13.1 ± 5.6), leading to a statistically higher chance of flap insufficiency. The insufficiency was more often found in female patients.

CONCLUSION: The risk of NSF insufficiency for covering the anterior skull-base defect in Koreans is higher relative to whites, and is accentuated in female patients. Efforts to increase the size of the NSF as well as efforts to avoid intraoperative shrinkage of the NSF should be considered to compensate for the relatively small NSF in Asians.