Transsphenoidal Extent of Resection Study

The treatment of choice for most patients with symptomatic nonfunctioning pituitary adenomas
is transsphenoidal surgery to improve vision by decompression of the optic chiasm, to prevent
the development of endocrine dysfunction, and to treat neurological symptoms such as headache
or cranial neuropathies caused by the tumor. The most widely accepted surgical technique is
microscopic transsphenoidal surgery, in which an operating microscope is used by the surgeon
to provide surgical visualization and a nasal speculum is used to maintain the operative
corridor. [1-4] Recently, fully endoscopic transsphenoidal surgery, in which surgical
visualization is achieved using an endoscope, has been adopted by many pituitary surgeons
because the technique offers superior panoramic and angled visualization of the surgical
target and may permit greater tumor resection. [5-10] There is a vigorous debate in the
neurosurgical community about the relative merits of the microscopic and endoscopic
techniques. Proponents of the endoscopic technique argue that the superior visualization
permits more aggressive tumor resection and better preservation of the normal pituitary
gland. Proponents of the microscopic technique argue that it permits shorter operative times,
results in similar surgical outcomes, and has a lower complication rate.

Despite the adoption of fully endoscopic surgery by many surgeons, no prospective studies
have compared the extent of tumor resection (EOR) between microscopic and endoscopic
approaches. Numerous retrospective studies have established the efficacy of each approach,
but only a few studies present comparative data.[11-13] Recently, McLaughlin et al. noted
that the addition of endoscopy to microscopic pituitary surgery enhances tumor removal,
particularly in patients with tumors greater than 20 mm in diameter. [14] This study raises
the intriguing possibility that certain subgroups of patients (e.g. patients with larger
tumors) may benefit from endoscopic surgery. In patients with smaller tumors with no
cavernous sinus invasion, others have shown that the techniques achieve similar EOR. [15]
That endoscopy may permit more complete tumor resections is a testable hypothesis.

Inclusion Criteria:

- Patients with suspected nonfunctioning pituitary macroadenomas (≥ 1 cm) with planned
transsphenoidal surgery

- Adults (age 18-80 years)

- Medically stable for surgery

- Reasonable expectation that patient will complete study and be available for follow-up
assessments

Exclusion Criteria:

- Prisoners

- Pregnant women

- Patients with suspected functioning pituitary adenoma

- Unable to obtain MRI of the pituitary (e.g., pacemaker, anaphylaxis to gadolinium, low
GFR)

- Pituitary apoplexy