Figure - available from: Frontiers in Oncology
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Side-firing intraoperative ultrasound in endoscopic endonasal pituitary surgery. (A) Schematic image depicting the scanning window of the side-firing ultrasound transducer. A digital ultrasound probe model is superimposed onto a T1 post-gadolinium MRI. (B) Intraoperative ultrasound image from the same patient showing intraoperative imaging of the surrounding parasellar anatomy. During image acquisition, the probe tip was abutted to the inferior surface of the diaphragma sellae, as demonstrated in Figure 1A. (C) Side-firing IOUS image showing pituitary adenoma tissue and the location of the cavernous segment of the Internal Carotid artery (cavernous ICA). The IOUS probe is directed laterally within the sella turcica. This image demonstrates the ability to identify critical structures and their relationship to the tumor tissue. (D) IOUS can be used to obtain tumor size data intraoperatively. The yellow symbols (+) in the above image indicate the location of the measurement, with the results displayed in the bottom left corner.
Source publication
Introduction
Multiple intraoperative navigation and imaging modalities are currently available as an adjunct to endoscopic transsphenoidal resection of pituitary adenomas, including intraoperative CT and MRI, fluorescence guidance, and neuronavigation. However, these imaging techniques have several limitations, including intraoperative tissue shift...
Citations
... Alternatively, intraoperative ultrasound (IOUS) presents a fast, costeffective, and recently widely available option. IOUS provides real-time visualization of nearby anatomy, allowing the surgeon to estimate the extent of resection and the location of critical structures with greater confidence (7,8). Both end-firing and side-firing ultrasound probes are available for the endoscopic endonasal approach, but side-firing ultrasound may be favorable for the purpose of navigating the surrounding anatomy of the paraclival region. ...
... End-firing probes are limited mainly to depth assessment, while side-firing probes enhance understanding of anatomy adjacent to the probe tip and potentially beyond the endoscopic field of view (9). Side-firing IOUS is a safe and effective adjunct to endoscopic endonasal surgery that can reduce operative time and increase the surgeon's confidence in the extent of resection (8). We previously published the results of a case-control study demonstrating the utility of side-firing IOUS in the resection of large and giant pituitary adenomas (8). ...
... Side-firing IOUS is a safe and effective adjunct to endoscopic endonasal surgery that can reduce operative time and increase the surgeon's confidence in the extent of resection (8). We previously published the results of a case-control study demonstrating the utility of side-firing IOUS in the resection of large and giant pituitary adenomas (8). In this report, we describe the first use of a minimally invasive side-firing IOUS probe in the resection of a large complex clival chordoma. ...
Clival chordomas are locally invasive midline skull base tumors arising from remnants of the primitive notochord. Intracranial vasculature and cranial nerve involvement of tumors in the paraclival region necessitates image guidance that provides accurate real-time feedback during resection. Several intraoperative image guidance modalities have been introduced as adjuncts to endoscopic endonasal surgery, including stereotactic neuronavigation, intraoperative ultrasound, intraoperative MRI, and intraoperative CT. Gross total resection of chordomas is associated with a lower recurrence rate; therefore, intraoperative imaging may improve long-term outcomes by enhancing the extent of resection. However, among these options, effectiveness and accessibility vary between institutions. We previously published the first use of an end-firing probe in the resection of a clival chordoma. End-firing probes provide a single field of view, primarily limited to depth estimation. In this case report, we discuss the benefits of employing a novel minimally invasive side-firing ultrasound probe as a cost-effective and time-efficient option to navigate the anatomy of the paraclival region and guide endoscopic endonasal resection of a large complex clival chordoma.
Objective:
The primary objective of this systematic review is to evaluate the effectiveness of intraoperative ultrasound (IOUS) in improving outcomes in patients undergoing pituitary surgery.
Method:
A systematic review was performed by searching MEDLINE (PubMed), Web of Science, Scopus, and Embase electronic bibliographic databases from conception to 2022.
Results:
The included studies yielded a total of 660 patients, with 488 patients undergoing IOUS. Outcome were available for 341 patients treated with IOUS and 157 patients who were treated without the IOUS application, and the remission rates following surgery were 76% and 59%, respectively. Only two studies reported remission rates for both groups, and meta-analysis for these studies showed significant superiority of intraoperative ultrasonography (Random effect, OR 4.99, P<0.01). Regarding extent of resection, IOUS resulted in 71% gross total resection, while absence of IOUS yielded a gross total resection rate of 44%. Among studies with available follow-up on IOUS, the recurrence rate was 3%. Pituitary dysfunction (34%), cerebrospinal fluid leak (31%), and central nervous system infection (8%) were the most common complications in the IOUS group. The mean follow-up was 19.97 months in studies reporting follow-up time.
Conclusions:
The application of the IOUS is both safe and effective and could improve the outcome of pituitary surgeries. IOUS can assist surgeons in the identification of pituitary tumors and their surrounding anatomy and can help minimize the risk of complications associated with this complex surgical procedure.
Background:
Suprasellar extension, cavernous sinus invasion, and involvement of intracranial vascular structures and cranial nerves are among the challenges faced by surgeons operating on giant pituitary macroadenomas. Intraoperative tissue shifts may render neuronavigation techniques inaccurate. Intraoperative MRI can solve this problem, but it may be costly and time consuming. However, intraoperative ultrasound (IOUS) allows for quick, real-time feedback and may be of particular utility when facing giant, invasive adenomas. Here, we present the first study examining technique for IOUS-guided resection specifically focusing on giant pituitary adenomas.
Objective:
To describe the use of a side-firing ultrasound probe in the resection of giant pituitary macroadenomas METHODS: We describe operative technique using a side-firing ultrasound probe (Fujifilm/Hitachi) to identify the diaphragma sellae, confirm optic chiasm decompression, identify vascular structures related to tumor invasion, and maximize extent of resection in giant pituitary macroadenomas RESULTS: Side-firing IOUS allows for identification of the diaphragma sellae to help prevent intraoperative CSF leak while maximizing extent of resection. Side-firing IOUS also aids in confirmation of decompression of the optic chiasm via identification of a patent chiasmatic cistern. Furthermore, direct identification of the cavernous and supraclinoid internal carotid arteries (ICAs) and arterial branches is achieved when resecting tumors with significant parasellar and suprasellar extension.
Conclusion:
We describe an operative technique in which side-firing IOUS may assist in maximizing extent of resection and protecting vital structures during surgery for giant pituitary adenomas. Use of this technology may be particularly valuable in settings where intraoperative MRI is not available.
