Introduction: Intraoperative ultrasonography (IOUS) for pituitary tumors was pioneered by Oldfield, who showed greater detection and remission rates in cases of Cushing's disease (1). In addition to detection and resection of microadenomas, IOUS has proved beneficial in identifying macroadenomas, pituitary cysts, and craniopharyngiomas as well as normal sellar and parasellar structures(2). Here, the authors describe the use of a novel sterile, disposable, 2.86 mm diameter side-firing 6.6 to 13.0 Mhz ultrasound probe for the use in transsphenoidal pituitary surgery.

Methods: Patients with pituitary region lesions were retrospectively reviewed over a 3 year period. 84 cases were identified, 16 of which were performed with IOUS. Data was analyzed for complications (CSF leaks, postoperative pituitary dysfunction, and blood loss), length of hospital stay, extent of resection and associated costs related to the surgery and postoperative course.

Results: The group of patients in which IOUS was used had a greater rate of tumor gross total resection (75% vs. 49%), shorter operative times (77 vs. 148 min), a decreased hospital length of stay (3.1 vs 4.2 days), lower intraoperative CSF leak rates (25% vs. 50%), less operative blood loss (159 vs. 304 cc), no vascular injuries (0% vs. 1.5%) and a lower rate of postoperative pituitary dysfunction (19% vs. 26%). This translates to a savings of approximately $2,700 even after the costs of the UST-5311-TIP ultrasound transducer is factored in.

Conclusions: There is a demand for cost-effective, reliable and widely available intraoperative imaging during pituitary surgery. IOUS fits this profile and has a long history of use in pituitary surgery with favorable outcomes reported here and elsewhwere (3)(4)(5). The use of IOUS in pituitary surgery may result in increased extent of resection, decreased OR time, blood loss, hospital length of stay, CSF leaks, pituitary dysfunction, vascular injury and resulting associated costs.

Patient Care: Appropriate and effective use of interoperative ultrasound in transsellar surgery can result in improved patient outcomes and lower overall hospital cost compared to cases in which it is not utilized.

Learning Objectives: By the conclusion of this session, participants should be able to 1)describe the importance and applications of interoperative ultrasound use 2) discuss the benefits of IOUS, and 3) Identify appropriate clinical scenarios for IOUS and discuss interpretation of IOUS findings.

References: 1. Watson JC, Shawker TH, Nieman LK, DeVroom HL, Doppman JL, Oldfield EH: Localization of pituitary adenomas by using intraoperative ultrasound in patients with Cushing's disease and no demonstrable pituitary tumor on magnetic resonance imaging. J Neurosurg 89:927-932, 1998 2.Doppman JL, Ram Z, Shawker TH, Oldfield EH: Intraoperative US of the pituitary gland. Work in progress. Radiology 192:111-115, 1994 3.Marcus HJ, Vercauteren T, Ourselin S, Dorward NL: Intraoperative Ultrasound in Patients Undergoing Transsphenoidal Surgery for Pituitary Adenoma: Systematic Review [corrected]. World Neurosurg 106:680-685, 2017 4.Solheim O, Selbekk T, Lovstakken L, Tangen GA, Solberg OV, Johansen TF, et al: Intrasellar ultrasound in transsphenoidal surgery: a novel technique. Neurosurgery 66:173-185; discussion 185-176, 2010 5.Arita K, Kurisu K, Tominaga A, Kawamoto H, Iida K, Mizoue T, et al: Trans-sellar color Doppler ultrasonography during transsphenoidal surgery. Neurosurgery 42:81-85; discussion 86, 1998