Use of intraoperative intracavitary (direct-contact) ultrasound for resection control in transsphenoidal surgery for pituitary tumors: evaluation of a microsurgical series

Intraoperative Ultrasonography in Pituitary Surgery Revisited: An Institutional Experience and Systematic Review on Applications and Considerations

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.

METHODS

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 2 studies reported remission rates for both groups, and meta-analysis for these studies showed significant superiority of intraoperative ultrasonography (Random effect, odds ratio 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.

Side-Firing Intraoperative Ultrasonograhy for Resection of Giant Pituitary Adenomas

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 magnetic resonance imaging can solve this problem, but it may be costly and time consuming. However, intraoperative ultrasonography (IOUS) allows for quick, real-time feedback and may be particularly useful 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 an 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 cerebrospinal fluid leak and maximize 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 and arterial branches is achieved when resecting tumors with significant parasellar and suprasellar extension.

CONCLUSIONS

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 in which intraoperative magnetic resonance imaging is not available.

Endoscopic ultrasound imaging with high flow mode for endonasal transsphenoidal pituitary surgery

Intraoperative ultrasound during transsphenoidal surgery (TSS) for pituitary tumors has been reported. In reports of endonasal ultrasound (US), Doppler US vessel images were informative and effective in endoscopic TSS. We performed endoscopic US imaging with high flow mode, which is a novel technology, to visualize small vessels during endonasal endoscopic TSS. Six patients (five with pituitary adenomas and one with Rathoke's cleft cyst) underwent endoscopic US-assisted TSS. A small endoscopic US probe (Olympus, BF-UC260FW; diameter, 6.9 mm) was inserted transsphenoidally to the sellar floor and into the sella turcica, and endoscopic US monitoring was performed. By rotating the endoscopic US probe, the internal carotid artery, anterior cerebral artery, middle cerebral artery, various small vessels, optic nerve, and residual tumor were clearly visualized on the endoscopic US images. Real-time animated vessel images around the tumor could be generated when needed during TSS. The tumors were removed without leakage of cerebrospinal fluid in the six patients, and their visual acuity was restored. Endoscopic US with high flow mode can visualize not only main cerebral arteries but also intracranial small vessels on B-mode US images. Pituitary tumors were clearly recognized and removed safely and precisely by monitoring the cerebral artery and its small branches as landmarks.

Integrated multi-modality image-guided navigation for neurosurgery: open-source software platform using state-of-the-art clinical hardware

PURPOSE

Image-guided surgery (IGS) is an integral part of modern neuro-oncology surgery. Navigated ultrasound provides the surgeon with reconstructed views of ultrasound data, but no commercial system presently permits its integration with other essential non-imaging-based intraoperative monitoring modalities such as intraoperative neuromonitoring. Such a system would be particularly useful in skull base neurosurgery.

METHODS

We established functional and technical requirements of an integrated multi-modality IGS system tailored for skull base surgery with the ability to incorporate: (1) preoperative MRI data and associated 3D volume reconstructions, (2) real-time intraoperative neurophysiological data and (3) live reconstructed 3D ultrasound. We created an open-source software platform to integrate with readily available commercial hardware. We tested the accuracy of the system's ultrasound navigation and reconstruction using a polyvinyl alcohol phantom model and simulated the use of the complete navigation system in a clinical operating room using a patient-specific phantom model.

RESULTS

Experimental validation of the system's navigated ultrasound component demonstrated accuracy of [Formula: see text] and a frame rate of 25 frames per second. Clinical simulation confirmed that system assembly was straightforward, could be achieved in a clinically acceptable time of [Formula: see text] and performed with a clinically acceptable level of accuracy.

CONCLUSION

We present an integrated open-source research platform for multi-modality IGS. The present prototype system was tailored for neurosurgery and met all minimum design requirements focused on skull base surgery. Future work aims to optimise the system further by addressing the remaining target requirements.

Creative and Innovative Methods and Techniques for the Challenges in the Management of Adult Craniopharyngioma

Craniopharyngioma remains a major challenge in daily clinical practice. The pathobiology of the tumor is still elusive, and there are no consensus or treatment guidelines on the optimal management strategy for this relatively rare tumor. However, recent technical and scientific advances, including genomic and radiomic profiling, innovation in surgical approaches, more precise radiotherapy protocols, targeted therapy, and restoration of lost functions all have the potential to significantly improve the outcome of patients with craniopharyngioma in the near future. Although many of these innovative tools in the new armamentarium of the clinician are still in their infancy, they could reduce craniopharyngioma-related morbidity and mortality and improve the patients' quality of life. In this article, we discuss these creative and innovative approaches that may offer solutions to the obstacles faced in treating craniopharyngioma and future possibilities in improving the care of these patients.

Current Limitations of Intraoperative Ultrasound in Brain Tumor Surgery

While benefits of intraoperative ultrasound (IOUS) have been frequently described, data on IOUS limitations are relatively sparse. Suboptimal ultrasound imaging of some pathologies, various types of ultrasound artifacts, challenging patient positioning during some IOUS-guided surgeries, and absence of an optimal IOUS probe depicting the entire sellar region during transsphenoidal pituitary surgery are some of the most important pitfalls. This review aims to summarize prominent limitations of current IOUS systems, and to present possibilities to reduce them by using ultrasound technology suitable for a specific procedure and by proper scanning techniques. In addition, future trends of IOUS imaging optimization are described in this article.