Clinical significance of MRI-aided measurements in the transsphenoidal approach in Chinese adults

To determine the optimal direction for approaching sellar tumors, we developed an anatomical model of the most common approach, the transsphenoidal approach, in Chinese adults by analyzing MRI-aided measurements. Craniocerebral MRI of 75 Chinese adults with pituitary tumors and 238 healthy Chinese adults were obtained to analyse the angle between the direction of the transsphenoidal approach and the reference line linking the glabella and the external occipital tubercle, the approach depth, and the distance between the internal carotid arteries (ICA) at the cavernous sinuses segment. The mean angle (± standard deviation [SD]) between the direction of the transsphenoidal approach and the reference line in patients with sellar tumors was 40.51 ± 2.98°, similar to the angle in the healthy control group (41.18 ± 3.35°) (p > 0.05). The mean depth (± SD) calculated via the transsphenoidal approach in the sellar tumor group was 86.01 ± 4.99 mm, which was similar to the control group (85.34 ± 4.96 mm) (p > 0.05). However, the mean distance (± SD) between the bilateral ICA at the cavernous sinuses in the patients with sellar tumors was 22.68 ± 5.03 mm, greater than in the control group (15.89 ± 3.11 mm) (p < 0.01). Thus, during sellar tumor resection via the transsphenoidal approach, the patient’s head should be first positioned to allow the line linking the glabella and the external occipital tubercle to be perpendicular to the horizontal plane, and then inclined backwards at an angle of about 40°. The floor of the sella, at a depth of about 85 mm, can then be reached vertically by introducing a speculum via a single nostril. The operative field should be limited to about 1 cm from the midline. By adopting this method, the optimal angle and depth of the transsphenoidal approach can be determined without complicated equipment. Moreover, this technique is simple and accurate enough to maintain the correct approach, locate the lesion, and reduce the incidence of serious postoperative complications, including bleeding caused by rupture of the ICA.