Intraoperative MRI And Neuronavigation For Transsphenoidal Endoscopic Surgery Of Large Pituitary Adenomas

Objective To investigate the impact of intraoperative Magnetic Resonance Imaging(iMRI) and neuronavigation for the transsphenoidal endoscopic surgery of largepituitary adenomas with diameter equal or greater than3cm. The indications,workflow, and complications of this technique are also discussed and analized.Methods From February2009to February2014,110cases of large pituitaryadenomas were enrolled in this study. Among them,96cases were intended to havegross total resection, while14cases were intended to have subtotal resection.High-field-strength (1.5T) iMRI and neuronavigation assisted endoscopictranssphenoidal resection were applied. Both clinical and imaging data, includingclinical manifestations, endocrine changes, peri-and intra-operative imaging data,time of procedure, postoperative complications, and follow-up information wereprospectively collected and analyzed. Results With iMRI, the first intra-operativescan revealed, that in the group with pre-operative intention of total resection,45cases (46.9%,45/96cases) had gross total resection.30cases（31.3%,30/96cases）had further resection after iMRI scan and finally got gross total resection, whichincreased the gross total resection rate from46.9%to78.1%in the end. With iMRIand neuronavigation, the total resection rate in this group increased by31.2%(p <0.01). Finally, there were21cases (21.9%,21/96cases) with tumor reminents in thisgroup. For those cases who were intended to have only subtotal resection,14caseshad subtotal resection. So, in the whole cohort, only35patients (31.8%,35/110cases)had tumor reminents. There are17patients (15.5%) developed intra-operativecerebrospinal fluid leakage, which were repaired instantly. Intraoperative MRI scanextended the operation for62±21minutes. Headache was reliefed in73cases(91.3%,73/80cases, p <0.01). Visual disturbances improved in77cases (85.6%,77/90, p <0.01). There were only2patients (1.8%) suffered from aggrevated visual impairment post-operatively. One patient died from subarachnoid saddle areahemorrhage20days after surgery. Transient diabetes insipidus were found in43patients (39.1%), while long-term (longer than3months) diabetes insipidus happenedin5cases (4.5%). New-onset of postoperative hypopituitarism were found in21cases (19.1%). Procedure related nasal and paranasal sinus complications occurredin40cases (36.4%). Two patiens (1.8%) had post-operative intracranial infection.Follow-up period ranged from3to60months. The recurrence rate was13.6%(15/110cases). Conclusion With iMRI and neuronavigation, the extent of resectionof pituitary tumors can be evalueated and controlled intra-operatively, which hassignificantly improved the gross total resection rate for large pituitary adenomas.Multimodal neuronavigation and iMRI are helpful to improve the safety ofendoscopic transsphenoidal surgery. However, iMRI did extend time of procedure.Hence, it still needs further exploration to verify if this technique may induce higherpotential risks of infection and anesthesia-related complications.