Insertion of intra-oral electrodes for cranial nerve monitoring using a Crowe-Davis retractor

[Advances in Intraoperative Neurophysiological Monitoring Techniques in Transnasal Endoscopic Skull Base Surgery]

Transnasal endoscopic skull base surgery has been increasing in volume in recent years and its indications are constantly expanding. The potential occurrence of intraoperative and postoperative neurovascular complications deserves special attention from neurosurgeons. Multimodal intraoperative neurophysiological monitoring technology allows neurosurgeons to monitor cerebral perfusion and the functional status of the associated cranial nerves in real time, thereby enabling surgeons to make prompt adjustments in surgical procedures and strategies and reduce the risks of postoperative neurological complications in patients. Based on available literature, we reviewed how appropriate monitoring strategies were optimized for different key components of transnasal endoscopic skull base procedures, intending to provide reference for clinicians.

The Feasibility of Anterior Occipital Condyle Screw for the Reconstruction of Craniovertebral Junction: A Digital Anatomical and Cadaveric Study of a Novel Technique

Background

Anterior occipital condyle screw (AOCS) could be a feasible alternative technique for occipitocervical fusion for reconstruction of craniovertebral junction. This study aimed to analyze the feasibility of AOCS.

Methods

The craniovertebral junction computed tomography (CT) scans of 40 adults were enrolled and imported into Mimics software. Then, the three-dimensional reconstruction digital model of craniovertebral junction was established to determine entry point, insertion angle, and screw’s trajectory. After AOCS insertion into ten human cadaver spine specimens, CT scans were performed to verify the location between screws and important structures.

Results

The optimal entry point was located caudally and medial to the ventral of occipital condyle. The optimal trajectory was in inclination angle (5.9°±3.4°) in the sagittal plane and divergence angle (26.7°±6.0°) in the axial plane with the screw length around 21.6±1.2mm. None of the screws invaded the hypoglossal canal and vertebral artery in any of the specimens.

Conclusion

AOCS fixation is a feasible, novel technique for anterior craniovertebral junction reconstruction, and it could be an effective alternative operation for anterior reconstruction with titanium mesh cage.