A biokinetic model for nickel released from cardiovascular devices.

Many alloys used in cardiovascular device applications contain high levels of nickel, which if released in sufficient quantities, can lead to adverse health effects. While nickel release from these devices is typically characterized through the use of in-vitro immersion tests, it is unclear if the rate at which nickel is released from a device during in-vitro testing is representative of the release rate following implantation in the body. To address this uncertainty, we have developed a novel biokinetic model that combines a traditional toxicokinetic compartment model with a physics-based model to estimate nickel release from an implanted device. This model links the rate of in-vitro nickel release from a cardiovascular device to serum nickel concentrations, an easily measured endpoint, to estimate the rate and extent of in-vivo nickel release from an implanted device. The model was initially parameterized using data in the literature on in-vitro nickel release from a nickel-containing alloy (nitinol) and baseline serum nickel levels in humans. The results of this first step were then used to validate specific components of the model. The remaining unknown quantities were fit using serum values reported in patients following implantation with nitinol atrial occluder devices. The model is not only consistent with levels of nickel in serum and urine of patients following treatment with the atrial occluders, but also the optimized parameters in the model were all physiologically plausible. The congruity of the model with available data suggests that it can provide a framework to interpret nickel biomonitoring data and use data from in-vitro nickel immersion tests to estimate in-vivo nickel release from implanted cardiovascular devices.

Quantifying Nipple-Areolar Complex Shape and Location After Transmasculine Top Surgery: A Study of Postoperative Photographs Posted on Social Media and Surgeons' Professional Websites.

Purpose: The transgender community utilizes online platforms to view and share postoperative masculinizing top surgery photographs. However, the quantitative and qualitative nature of these photographs is unknown. We aimed to conduct an analysis of postoperative online photographs for nipple-areolar complex (NAC) shape and location, and compare social media platforms to World Professional Association for Transgender Health (WPATH) surgeons' websites and published cis-male chest proportions. Methods: In a cross-sectional analysis (April to May 2019), social media (Instagram and Reddit) and WPATH surgeon website postoperative top surgery photographs were analyzed. Areola height (AH):areola width (AW), NAC horizontal (inter-nipple distance [IND]:chest width [CW]) and vertical placement (sternal notch to nipple line [SN-NL]:sternal notch to umbilicus [SN-U]), and vertical scar placement (sternal notch to scar line [SN-SL]:SN-U) ratios were assessed on MATLAB. Data were compared to published cis-male proportions. Photograph skin color, soft tissue redundancy, and scar location were also analyzed. Results: We analyzed 304 social media and 192 surgeons' website photographs qualitatively, and 139 social media and 189 surgeons' photographs quantitatively. Means (standard deviation) for postoperative photographs were AH:AW 1.12±0.24, IND:CW 0.68±0.07, SN-NL:SN-U 0.37±0.06. Most ratios significantly differed from published cis-male ratios (p<0.001). Photographs from WPATH surgeons' websites differed from social media platforms in SN-NL:SN-U and SN-SL:SN-U (p<0.001), and in scar location and soft tissue redundancy (p=0.012). Conclusion: Postoperative top surgery photographs on online platforms showed more vertically oval, caudally positioned, and in many cases wider-spaced NACs than cis-male proportions. Our study highlights variability in results of masculinizing top surgery as it relates to an emerging source of information; online photographs.

Automatic summarization of endoscopic skull base surgical videos through object detection and hidden Markov modeling.

Endoscopic endonasal surgery is a medical procedure that utilizes an endoscopic video camera to view and manipulate a surgical site accessed through the nose. Despite these surgeries being video recorded, these videos are seldom reviewed or even saved in patient files due to the size and length of the video file. Editing to a manageable size may necessitate viewing 3 h or more of surgical video and manually splicing together the desired segments. We suggest a novel multi-stage video summarization procedure utilizing deep semantic features, tool detections, and video frame temporal correspondences to create a representative summarization. Summarization by our method resulted in a 98.2% reduction in overall video length while preserving 84% of key medical scenes. Furthermore, resulting summaries contained only 1% of scenes with irrelevant detail such as endoscope lens cleaning, blurry frames, or frames external to the patient. This outperformed leading commercial and open source summarization tools not designed for surgery, which only preserved 57% and 46% of key medical scenes in similar length summaries, and included 36% and 59% of scenes containing irrelevant detail. Experts agreed that on average (Likert Scale = 4) that the overall quality of the video was adequate to share with peers in its current state.

Migration of Broken Dental Needle Through the Internal Jugular Vein in the Parapharyngeal Space.

Accidental broken dental needles during dental blocks have become a rare occurrence but still occur. Although the treatment for such occurrence is controversial, an increasing body of literature demonstrates that migration of such needles is possible. In this case, we report on a 48-year-old male with migration of a broken dental needle from an inferior alveolar block. Over the course of 2 years, we demonstrated radiological documentation of the course of migration with penetration of the internal jugular vein at the jugular foramen which was subsequently successfully retrieved through a transcervical approach without neurovascular injury. This case is unique given the location of migration to the skull base as well as radiologically documented time course. Furthermore, it highlights the need for prompt retrieval of broken dental needles given the high potential of migration and injury to neurovascular structures.

Facial Nerve Branching Patterns Vary With Vascular Anomalies.

OBJECTIVES: At our institution, in vivo facial nerve mapping (FNM) is used during vascular anomaly (VAN) surgeries involving the facial nerve (FN) to create an FN map and prevent injury. During mapping, FN anatomy seemed to vary with VAN type. This study aimed to characterize FN branching patterns compared to published FN anatomy and VAN type. STUDY DESIGN: Retrospective study of surgically relevant facial nerve anatomy. METHODS: VAN patients (n = 67) with FN mapping between 2005 and 2018 were identified. Results included VAN type, FN relationship to VAN, FNM image with branch pattern, and surgical approach. A Fisher exact test compared FN relationships and surgical approach between VAN pathology, and FN branching types to published anatomical studies. MATLAB quantified FN branching with Euclidean distances and angles. Principal component analysis (PCA) and hierarchical cluster analysis (HCA) analyzed quantitative FN patterns amongst VAN types. RESULTS: VANs included were hemangioma, venous malformation, lymphatic malformation, and arteriovenous malformation (n = 17, 13, 25, and 3, respectively). VAN FN patterns differed from described FN anatomy (P < .001). PCA and HCA in MATLAB-quantified FN branching demonstrated no patterns associated with VAN pathology (P = .80 and P = .91, one-way analysis of variance for principle component 1 (PC1) and priniciple component 2 (PC2), respectively). FN branches were usually adherent to hemangioma or venous malformation as compared to coursing through lymphatic malformation (both P = .01, Fisher exact). CONCLUSIONS: FN branching patterns identified through electrical stimulation differ from cadaveric dissection determined FN anatomy. This reflects the high sensitivity of neurophysiologic testing in detecting small distal FN branches. Elongated FN branches traveling through lymphatic malformation may be related to abnormal nerve patterning in these malformations. LEVEL OF EVIDENCE: NA Laryngoscope, 130:2708-2713, 2020.