Objective: Subtemporal anterior petrosectomy is a complex neurosurgical procedure demanding
the identification and preservation of critical anatomical structures. This technical
note introduces microscopic real-time near-infrared indocyanine (NIR-ICG) fluorescence
and white light overlay modality to this approach, enhancing the intraoperative real-time
and flow-dependent visualization of critical vascular structures. We aimed to test
its feasibility and accordance with anatomical landmarks for planning posteromedial
(Kawase) rhomboid drilling.
Methods: We describe our experience integrating NIR indocyanine and white light overlay technology
for subtemporal anterior petrosectomy. This simple adjunct technique involves using
a novel robotic microscope (ZEISS KINEVO 900) and the built-in FLOW800 and INFRARED800
functions with fluorescence capabilities to provide simultaneous ocular overlay of
NIR indocyanine and conventional white light images. Intraoperative video frames and
significant images were collected; technical nuances, surgical time, operator feedback,
and outcomes were discussed.
Results: The integration of real-time NIR indocyanine and white light overlay visualization
during subtemporal anterior petrosectomy was a valuable adjunct in enhancing the surgeon's
ability to identify or confirm the location of the carotid canal and its segments,
superior petrosal sinus, greater superficial petrosal nerve, Gasserian ganglion and
trigeminal branches with improved precision and safety. This technique might reduce
the risk of iatrogenic vascular injury, help define boundaries of the drilling window,
improve surgical exposure, and guarantee additional procedural safety with no extra
surgical time given the real-time digital overlay of NIR imaging onto white light
ocular output.
Conclusion: The application of microscopic real-time NIR indocyanine and white light overlay
visualization represents a well-established technique. However, although identifying
and preserving critical neurovascular structures is essential, its implementation
during subtemporal anterior petrosectomy and other skull base procedures requiring
extensive drilling has been poorly investigated. This approach offers the surgeon
a comprehensive and real-time view of the overall surgical field and petrous ICA,
thereby contributing to safer and more successful surgical planning of posteromedial
rhomboid aperture beyond static anatomical landmarks. Further investigation is required
to suggest a widespread adoption of this simple technique to improve patients’ safety
and outcomes in complex neurosurgical procedures.
