Table 3.

Linear regression models for 3 distances with age under 3 different surgical positions

Distances, cm	Positions
	Head-back position	Middle head position	Maximal flexion of the head
CT, cm	CT = 3.236 + 0.298 × age	CT = 2.443 + 0.256 × age	CT = 1.650 + 0.236 × age
CV, cm	CV = 8.362 + 0.403 × age	CV = 7.647 + 0.377 × age	CV = 6.902 + 0.364 × age
TV, cm	TV = 5.125 + 0.105 × age	TV = 5.291 + 0.111 × age	TV = 5.252 + 0.129 × age
		Position changes
	Middle head position to be Head-back position		Middle head position to be Maximal flexion of the head
CT, cm	CT = 2.290 + 0.277 × age* + 1.099 × Position change*		CT = 2.520 + 0.246 × age*-0.947 × Position change *
CV, cm	CV = 7.550 + 0.390 × age* + 0.909 × Position change *		CV = 7.693 + 0.370 × age*-0.838 × Position change *
TV, cm	TV = 5.312 + 0.108 × age*-0.208 × Position change		TV = 5.226 + 0.120 × age* + 0.90 × Position change

*P-value for regression coefficients < 0.05