Volumetric assessment of the sella turcica: a re-evaluation

BACKGROUND

The sella turcica volume is widely measured by the Di Chiro-Nelson method. The purpose is to compare the fidelity of a proposed volumetry method vs. the Di Chiro-Nelson method, using computed tomography (CT) images.

MATERIALS AND METHODS

Morphometric examination of 173 CT scans were included, of which 52.6% were female. The mean age was 53.2 ± 17.6 years. Considering the Di Chiro-Nelson method, two measurements were added for each axis in the CT evaluation: length (central, left, and right), width (central, anterior, and posterior), and height (central, left, and right).

RESULTS

The mean measurements were length: central 10.11 ± 1.44, left 7.45 ± 1.67, right 7.53 ± 1.59; width: central 12.27 ± 2.11, anterior 10.99 ± 1.92, posterior 10.10 ± 1.74; height: central 7.68 ± 1.38, left 7.16 ± 1.35, right 7.40 ± 1.41. A statistically significant difference between sexes was found only in the anterior width (p = 0.01). Using the proposed method, the volume was 342.2 ± 88.5 and 378. 6 ± 113.9 mm³, respectively for females and males (p = 0.02) vs. 476.1 ± 132.4 and 523.8 ± 186.0 mm3 (p = 0.05) using the Di Chiro-Nelson's method.

CONCLUSIONS

Women had significantly smaller sella turcica volume than men. This proposed method considers the sella turcica as a not strictly symmetrical structure and indicates reduced variation between the maximum and minimum values, compared to the Di Chiro-Nelson's. Our findings may be useful for reassessment the volume of the sella turcica as the measurements indicate a higher precision.

Morphometry of the aortic arch and its branches. A computed tomography angiography-based study

BACKGROUND

The current study aims to determine the prevalence of variations of the aortic arch using computed tomography angiography (CTA), as well as morphometries and gender correlations.

MATERIALS AND METHODS

A retrospective, transverse, observational and descriptive study of 220 CTA was performed. The branching pattern, most cranial vertebral level of the aortic arch, area of the proximal, middle and distal segments of the arch, area of each branch, and the path of atypical arteries were recorded. Results were analysed and stratified by gender.

RESULTS

The typical aortic arch branching pattern was present in 77.7% without statistical significance between genders. The most common variant was a two-branch pattern with a common trunk and a left subclavian (13.6%), followed by a typical branching pattern with an added left vertebral artery (7.3%). T3 was the most frequent cranial level (32.3%), followed by T2-T3 (26.8%), and T3-T4 (23.2%). The mean areas of the aortic arch were 685.5 ± 183.9, 476.1 ± 124.1, and 445.0 ± 145.1 mm2 for the proximal, middle and distal segments, with statistical difference between men and women in the middle and distal segments. Three paths of atypical arteries were identified: bifurcated vertebral artery (0.5%), aberrant right subclavian artery (0.5%), and left subclavian ostium obstruction (0.5%).

CONCLUSIONS

Mexican population has one of the highest prevalence of variations in the aortic arch branching pattern. The high probability of finding these should be taken into consideration when assessing patients. A standardised classification method would contemplate future un-reported findings, without causing confusion by the different numbers assigned by each author.

Avoiding iatrogenic injuries to the vertebral artery: A morphometric study of the vertebral artery-free dissection area

OBJECTIVE

To determine the area of a safety window that excludes the vertebral artery for the safe access of the occipital condyle screws during occipitocervical fixation.

METHODS

This study included 138 cervical computed tomography angiograms. Six measurements per side were made in each imaging study. These measurements are from the vertebral artery to (A) the mastoid process, (B) the mastoid incisura, (C) the posterior condylar fossa, (D) the occipital condyle in its midline, and (E) the medial border of the condyle. We also measured from the tip of the mastoid process to the lower border of the occipital condyle on its lateral side (F).

RESULTS

A total of 276 areas from 138 individuals were included, of which 51.4 % were men. The mean age was 54.2 ± 18.63 years. The mean variable measurements (mm) for all the population were 21 ± 4, 16 ± 3, 6 ± 2, 3 ± 2, 2 ± 1 and 35 ± 4 for variables A-F, respectively. We found significant differences between sex when we compared measurements A (p = 0.003), C (p = 0.001), D (p = 0.000) and F (p = 0.000). The incidence rate of dominance for the vertebral artery was 18.8 % and 30.4 % for right and left respectively.

CONCLUSION

Women had significantly smaller measures than men. This could indicate a higher risk of iatrogenic injury secondary to a smaller vertebral artery-free area. Results may guide surgeons in the pre-surgical planning aiming to reduce the risk of iatrogenic injuries to the vertebral artery.