DISCUSSION:
IMRI during transsphenoidal resection of pituitary tumors has the
capacity to maximize outcomes in a busy community hospital setting. Our
data shows that gross total resection was achieved and determined during
surgery in the majority of our patients (67% compared to 33%). This
shows that iMRI provides an advantage to help determine gross total
resection of a pituitary mass during a case in real time. This has the
potential to allow for maximal and safe complete removal of tumor bulk
during transsphenoidal resection in addition to limiting overly
aggressive resection in anatomically hazardous locations. The use of
iMRI allowed our team to not only achieve maximum tumor resection, it
also allowed the team to visualize decompression of vital nearby
neurovascular structures that pituitary tumors usually adhere to. For
example, decompression was able to be visualized in and around the
cavernous sinus, carotid arteries, and optic apparatus.
Our study also shows that iMRI can be used typically only one time
during a case. The frequency of iMRI use for our study was only one time
during most cases and this allowed our team to be efficient with
achieving the best results for our patients. IMRI was typically used
once during two key phases of the operation. It was used to identify
intraoperative residual tumor location or to confirm gross total
resection before closing. Using iMRI multiple times during a case is a
rare occurrence. Using iMRI only one time during a case can help to
avoid excessive increase to the usual operative timing for a surgeon and
increases in personnel needed for managing the iMRi.
We also found that there was a significant difference in the evidence of
post-operative tumor residual detected. Our study demonstrates that the
use of iMRI to achieve gross total resection in real time has the
ability to decrease the presence of residual tumor postoperatively in
patients. Our study found that there may be an enough positive
correlation between these two measures as residual tumor was found in
less patients post-operatively (32% compared to 68%). The reason for
residual tumor being seen post-operatively in 32% of our patients may
hinge on the variety of presentations and extent of tumor involvement
especially in unresectable high risk regions. In these cases it is our
impression that iMRI facilitates the decision to cease excessive
manipulation thereby improving safety and possibly decreasing time spent
during surgery in specific cases.