Image guidance in trans-sphenoidal surgery for giant pituitary adenomas: Luxury or necessity?

Abstract

Background

In spite of availability of image guidance (neuronavigation) at major centers around the world, most trans-sphenoidal surgeries for pituitary adenomas continue to be done under fluoroscopic control. On the other hand, the high mortality and morbidity for giant pituitary adenomas is mainly due to inadequate tumor removal.

Aims and Objectives

The objective of this study was to study to utility of image guidance in trans-sphenoidal surgeries for optimizing tumor removal in giant pituitary adenomas.

Materials and Methods

This was a prospective study carried out over a two years (January 2009-December 2010) in the Department of Neurosurgery, All India Institute of Medical Sciences. Patients with giant pituitary adenomas who underwent trans-sphenoidal surgery by the author were included. All surgeries were done under image-guidance only and no fluoroscopy was employed. Trajectory was defined using the image guidance and bone work done accordingly to optimize tumor removal. All patients had a contrast CT of the head done within 48 h of surgery to see for residual tumor.

Observations and Results

Sixteen patients with pituitary adenomas were operated using only image-guidance in the study period. Twelve patients had virgin tumors and four patients had recurrent/residual tumors. In four patients, noncontrast MR images were used in for image guidance and contrast CT images were used in the rest. The mean set up time for image-guidance was 11 min (range 7–15 min). The mean “overall accuracy of registration” was 1.6 mm (range 1.4–2.1 mm). The mean operating time was 72 min (range 52–96 min). In all cases, midline and the relation of the carotid artery to the sella could be confirmed using the image-guidance. There were no intraoperative complications. Postoperative scans showed residual tumor in nine patients. The residual tumor was <10% in four patients, <25% in four patients and >25% in one patient (with a fibrous recurrent/residual tumor).

Conclusions

Image guidance markedly improves the visualization of sellar floor and its relation to the carotid arteries, thereby improving the safety and quality of the surgical procedure, besides being free of limitations of fluoroscopy. More importantly the trajectory can be defined for optimizing tumor removal in such patients. Image-guidance can easily replace flouroscopy for trans-sphenoidal surgeries and when available should be the first choice when operating pituitary tumors trans-sphenoidally.

Key words

Giant pituitary adenoma - image guidance - neuronavigation - trans-sphenoidal

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