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Purpose: Surgery is a standard therapy for tympanojugular paragangliomas (TJP). Maintaining the quality of life (QoL) requires functional preservation. The flexible CO2 laser allows contact-free tumor removal. This retrospective study compares the postoperative functional outcomes of TJP surgery with and without the flexible CO2 laser. Methods: Between 2005 and 2019, 51 patients with TJP were surgically treated at a tertiary hospital. Until 2012, 17 patients received conventional surgery. Thereafter, the flexible laser was used in 34 patients. Tumor extend, pre- and postoperative cranial nerve function, and complications were compared between the groups. Results: The cohort consisted of 33 class A and B tumors and 18 class C and D tumors. Preoperative embolization was performed in 17 cases. Class C/D TJP were usually removed via an infratemporal fossa type A approach. Gross total tumor removal was achieved in 14/18 class C/D tumors. 3/51 patients suffered from long-term partial or complete facial palsy. No differences in post-therapeutic cranial nerve function or complications were noted between the conventional and laser group. One recurrence was observed after complete tumor resection. Conclusion: The flexible CO2 laser was shown to be a safe and effective alternative to conventional bipolar cauterization, which is appreciated by the surgeon in these highly vascularized tumors. Both techniques allowed a high tumor control rate and good long-term results also from a functional point of view. [ABSTRACT FROM AUTHOR]

There is still a lack in precise postoperative evaluation of the cochlea because of strong artifacts. This study aimed to improve accuracy of postoperative two-turn (2TL) and cochlear duct length (CDL) measurements by applying flat-panel volume computed tomography (fpVCT), secondary reconstruction (fpVCTSECO) and three-dimensional curved multiplanar reconstruction. First, 10 temporal bone specimens with or without electrode were measured in multi-slice computed tomography (MSCT), fpVCT and fpVCTSECO and compared to high-resolution micro-CT scans. Later, pre- and postoperative scans of 10 patients were analyzed in a clinical setting. Concerning 2TL, no statistically significant difference was observed between implanted fpVCTSECO and nonimplanted micro-CT in 10 temporal bone specimens. In contrast, there was a significant discrepancy for CDL (difference: −0.7 mm, P = 0.004). Nevertheless, there were no clinically unacceptable errors (±1.5 mm). These results could be confirmed in a clinical setting. Using fpVCTSECO, CDL was slightly underestimated postoperatively (difference: −0.5 mm, P = 0.002) but without any clinically unacceptable errors. fpVCTSECO can be successfully applied for a precise measurement of the cochlear lengths pre- and postoperatively. However, users must be aware of a slight systematic underestimation of CDL postoperatively. These results may help to refine electrode selection and frequency mapping. [ABSTRACT FROM AUTHOR]

Purpose: The risk/benefit-ratio of deep brain stimulation (DBS) depends on focusing the electrical field onto the target volume, excluding side-effect eliciting structures. Directional leads limiting radial current diffusion can target stimulation but add a spatial degree of freedom that requires control to align multimodal imaging datasets and for anatomical interpretation of stimulation. Unpredictable postoperative lead rotations have been reported. The extent and timing of rotation from the surgically intended alignment remain uncertain, as does the time point at which directional stimulation can be safely initiated without risking unexpected shifts in stimulation volume. We present a retrospective analysis of clinically indicated, repeated neuroimaging controls postimplantation in patients with directional DBS systems, which allow estimation of the amount and timing of postoperative lead rotation. Methods: Data from 67 patients with directional leads and multiple cranial computer tomographies (CCT) and/or rotation fluoroscopies at different postoperative time points were included. Rotation angles were detected based on CCT artifacts (n = 56) or direct visualization of lead segments on rotation fluoroscopies (n = 52). Cross-validation of both methods was conducted in patients who received both imaging modalities (n = 51). Results: Rotation angles deviated significantly (∼30°) from their intended 0° anterior/posterior orientation. Rotation was firmly established within the first postoperative day, with no additional torque in subsequent scans. The two methods highly correlated (right hemisphere: R2 = 0.94, left hemisphere: R2 = 0.91). Conclusion: Both methods for measuring rotation angles led to comparable results and can be used interchangeably. Directional stimulation settings can safely be initiated after the first postoperative day, without risking subsequent lead rotation-related anatomical shifts. [ABSTRACT FROM AUTHOR]

Cochlear implants (CI) are an established treatment for people with deafness or severe hearing loss. To restore patients' hearing an electrode array (EA) of the CI is inserted into the cochlea to stimulate the auditory nerve. Thereby, the exact positioning and gentle insertion of the EA is crucial for optimal hearing perception outcome. Currently, only microscopic vision is available for entering the cochlea, but the critical intracochlear process during EA insertion is like a "black box" and the surgeon has to rely on haptic feedback. Methods for visualizing the insertion process during surgery are inaccurate or not suitable for routine use due to radiation exposure. To address this problem, we developed a computer-assisted and image-guided cochlear implantation system with an exact real-time visualization of the EA position during the insertion process. The system is based on an electromagnetic tracking system that measures the position and orientation of a sensor integrated into the tip of a EA prototype and visualizes it in presurgical image data. A first experiment with our system showed that a EA prototype could be inserted into a cochlea of a human temporal bone and placed with an accuracy of [Formula: see text]. A maximum insertion angle of 120° was achieved.