Frameless stereotaxy for transsphenoidal surgery

OBJECTIVE: To evaluate the utility of performing transsphenoidal surgery wi th computer-assisted image guidance. METHODS: Thirty-seven patients underwent transsphenoidal surgery in which a frameless stereotactic system was used to confirm the trajectory to the se lla and to locate the anatomic midline. This technique was compared with ou r standard method of using an image intensifier to confirm the approach (n = 43). The numbers of complications associated with the approach, the times required to set up and perform each operation, and the average costs for e ach group were compared. RESULTS: There were no complications attributable to inaccurate localizatio n from the neuronavigational system. Additional setup time was necessary to calibrate and register the system; this represented a mean of 17 minutes i n transsphenoidal procedures performed for the first time (n = 30), whereas reoperations required an average of 22 minutes (n = 7) (P < 0.05). The ope rative times, defined as time from incision to closure, were not statistica lly different (P = 0.38). To reduce assistant variation, a subset of this g roup in which the same assistant was used (n = 18) was analyzed. The additi onal setup time was reduced to a mean of 12 minutes (P < 0.05). The total c ase times were actually reduced in this group (127 versus 133 min), but thi s was not statistically significant (P = 0.75). Fluoroscopy was not require d when frameless stereotaxy was used. The cost savings were partially offse t by the cost of the preoperative computed tomographic study necessary for fiducial registration and the additional cost of setup time in the operatin g room. When all factors were analyzed, an additional cost to the patient o f $318.00 was noted. The image guidance in axial, coronal, and sagittal pla nes provided by frameless stereotaxy was subjectively beneficial; it increa sed our confidence with the approach to the sella and intraoperative locali zation and was particularly helpful in reoperations where standard anatomic landmarks were distorted. CONCLUSION: Frameless stereotaxy is a technology that provides continuous, three-dimensional information for localization and surgical trajectory to t he surgeon and can be applied to transsphenoidal surgery with minimal addit ional cost and time requirements.