Applied anatomy for pituitary adenoma resection

Pituitary adenomas are common intracranial tumors, with a rising incidence in China. Excision is a mainstay therapy for this disease, and is often carried out via transfrontal, transsphenoidal or transpterional approaches. However, few studies have systematically addressed the regional anatomy involved in these microsurgical procedures. The present study attempted to establish some key anatomic measurements relevant to pituitary adenoma resection based on cadaver and computer tomography (CT) image studies.

Head specimens from 30 randomly selected formalin-fixed adult cadavers were used for anatomical analysis. Measurements were made on the base of the skull following removal of brain structures above the pituitary gland, and on the mid-sagittal plane of the cranium. Parameters were designed by considering the 3 above-mentioned common microsurgical approaches, and obtained on each head using a sliding caliper. Multi-level CT images from 30 individuals were also used for distance measurements between landmark structures that are relevant to these surgeries. All data were subjected to statistical analysis using the SPSS 11.5 software.

There was statistically significant difference (P < 0.05) of distance measured on cadavers relative to CT images in 3 sets of measurements related to the transfrontal surgical approach, i.e., distances from the midpoint of superciliary arch superior border to the cranial entrance of internal carotid arteries (ICAs), the opposite side entrance of ICA and to the genu of ICA. While regional anatomical analyses were carried out according to the transpterional approach, statistically significant difference was also found in 3 sets of distance measurements between cadaver and CT image data, with regard to the distances between the pterion and some landmark structures around the pituitary.

The present study provides key anatomical and CT image measurements involving the 3 conventionally used surgical approaches for pituitary tumor resection. The data implicate that while CT scan results can provide valuable guidelines for operations, cautions and adjustments are needed during surgery for sufficient tumor excision and protection of key blood vessels and nerves in the vicinity of the pituitary gland and around the surgical pathway.