Axel Boese

Background/Objectives: Establishing access is a hazardous step of laparoscopic surgery, and the widely used Veress needle offers only subjective tactile and auditory cues for peritoneal entry. Proximal vibroacoustic (VA) sensing captures needle–tissue interaction non-invasively and is known to contain a characteristic peritoneal puncture signature, which could help surgeons to precisely identify peritoneal entry. However, the VA signature has been evaluated only by retrospective, video-anchored and manual signal analysis. We investigate whether peritoneal entry can instead be detected automatically. Methods: Cavity entry is framed as a binary classification of VA signal segments, and four model families are benchmarked under a single unified protocol: a one-dimensional convolutional neural network (1D CNN), a multilayer perceptron, a bidirectional long short-term memory network (LSTM), and a support vector machine (SVM) with a radial basis function kernel. All models were trained, selected, and threshold-tuned on a synthetic abdominal phantom (996 segments) and tested once on an independent porcine cadaver dataset (154 cavity, 462 non-cavity signals) so that every test result measures generalisation across a phantom-to-porcine domain shift. Results: The 1D CNN performed the best (accuracy 0.869, AUROC 0.904, macro F1 0.833, cavity recall 0.818), closely followed by the SVM (AUROC 0.900, AUPRC 0.878). Conclusions: These results establish the feasibility of automatically detecting peritoneal entry across a phantom-to-porcine domain shift and extend the descriptive cadaveric characterisation of the puncture signature toward the automated machine learning-based detection of peritoneal entry in laparoscopic access with a Veress needle.

Background/Objectives: Establishing laparoscopic access remains a critical and complication-prone step in minimally invasive surgery. Previous work has shown that proximal vibroacoustic sensing can identify peritoneal puncture events in porcine cadavers. The present pilot study evaluated whether these findings translate to human anatomy under controlled, ex vivo conditions. Methods: A vibroacoustic sensing prototype was proximally attached to a standard Veress needle during 14 insertions into a fresh human body donor (within 48 h post-mortem). An endoscope was introduced laterally to provide visual ground truth of peritoneal entry. Vibroacoustic signals were recorded at the proximal end of the instrument. Time–frequency analyses, transient excitation detection, and statistical comparisons were performed to assess whether (1) peritoneal puncture can be identified in the vibroacoustic signal, (2) signal phases and dynamics correspond to those previously observed in porcine cadavers, and (3) peritoneal punctures can be statistically differentiated from non-peritoneal events. Results: All 14 peritoneal punctures were identifiable in the vibroacoustic signal under the experimental conditions. Characteristic signal phases previously described in porcine tissue, including transient excitation associated with cavity entry, were consistently reproduced with comparable temporal and spectral profiles. Statistical analyses demonstrated group-level differences between peritoneal and non-peritoneal events, and the peritoneal puncture was the highest-energy event of its insertion in 13 of 14 cases (92.9%). Conclusions: Under the controlled ex vivo conditions of this single-donor pilot study, vibroacoustic sensing was feasible for identifying peritoneal puncture in human tissue and reproduced signal dynamics observed in porcine models. To our knowledge, this is the first demonstration of the proximal vibroacoustic sensing concept on a human body donor and the first cross-species replication of the previously reported puncture phase structure, establishing an important translational stepping stone between animal cadaver studies and in vivo investigations. The study demonstrates feasibility rather than clinical reliability: the single-donor design and the retrospective annotation framework limit generalizability. Prospective validation in living patients, across multiple subjects and operators, is required before clinical deployment.

This study evaluates the use of vibroacoustic (VA) sensing to detect material transitions during needle insertions into layered synthetic phantoms. Experiments were conducted using foams with different pore densities and configurations including internal cavities. Time-domain and wavelet analyses showed that denser foams produced more frequent vibrational events, while less dense foams resulted in sparser signals. In setups with elastic membranes and cavities, differences in time-frequency patterns were observed: high-frequency activity appeared after membrane rupture but was absent in cavity insertions. These results support the use of VA sensing to identify mechanical changes during minimally invasive procedures.

Background/Objectives: Differentiating benign, premalignant, and early malignant vocal fold lesions is challenging. Perpendicular vascular changes (PVCs) per the European Laryngological Society (ELS) are key malignancy indicators. Enhanced contact endoscopy with narrow-band imaging (NBI-CE) visualizes intrapapillary capillary loops (IPCLs) at high magnification, independent of gross morphology. However, defining malignancy as any PVC increases sensitivity but lowers specificity—particularly in papillomas—whereas limiting malignancy to narrow-angle PVC improves specificity but risks false negatives and reduced reproducibility. Methods: We intraoperatively evaluated 146 histology-proven vocal fold lesions using NBI-CE. Six raters (three experienced otolaryngologists, three PhD students) classified vascular patterns. Two approaches were tested: (1) malignancy = narrow-angle PVC; (2) malignancy = any PVC. Outcomes were accuracy, sensitivity, specificity, and interrater agreement. Results: Approach (1) had higher specificity but lower sensitivity than (2) (~85% vs. ~70% specificity; ~50% vs. ~80% sensitivity). Accuracy did not differ significantly. Experienced raters showed higher interrater agreement and a more favorable sensitivity–specificity balance. Common errors were false positives in papillomas and false negatives in dysplasia/early carcinoma. Conclusions: PVC assessment with NBI-CE is feasible and informative. Choosing between “any PVC” and “narrow-angle only” entails a sensitivity–specificity trade-off and depends on lesion type and experience. Refined ELS descriptors and automated analysis may improve reproducibility and accuracy.

Background: Digital subtraction angiography lacks the ability to visualise intimal surface changes. Angioscopy, in contrast, enables direct imaging of the endoluminal surface, revealing luminal alterations, as established in cardiovascular imaging. Its application in the internal carotid artery (ICA) could allow assessment of pathological changes and the visualization of implant structures such as stents or flow diverters, including their apposition to the vessel wall. This study evaluates the feasibility of using a thin fibre-optic endoscope for angioscopy in the ICA anatomy. Methods: Five 3D DSA image sets of the ICA with varying anatomies were selected. Tube-based vessel models were fabricated to replicate the corresponding vascular segments, incorporating a measurement scale and, optionally, a stent or a flow diverter. The advancement of a fibre-optic endoscope and the related influence on vessel deformation were assessed in each model. Spatial and colour resolution were evaluated by applying coloured markings to the inner tube surface to simulate vessel wall discolouration. The visibility of structural details, including flow diverter meshes and stent struts, was assessed based on image contrast and sharpness within the angioscope’s defined field of view. Results: The endoscope was successfully advanced to the distal end in all models. Increased vascular curvature required greater mechanical force for navigation and positioning, leading to observable straightening of the vessel model. In all cases, endoscopic imaging produced clear visualizations of vessel wall markings and implant structures. Stent struts and flow diverter meshes were distinguishable, as were discolorations simulating pathological changes. Conclusion: Angioscopy of the ICA is technically feasible and enables endoluminal visualization, including implant structures. Feasibility was strongly dependent on vessel curvature and required substantial increases in delivery force in highly tortuous anatomies.

Background/Objectives: Differentiating benign, premalignant, and early malignant vocal fold lesions is challenging. Perpendicular vascular changes (PVC) per the European Lar-yngological Society (ELS) are key malignancy indicators. Enhanced contact endoscopy with narrow-band imaging (NBI-CE) visualizes intrapapillary capillary loops (IPCLs) at high magnification, independent of gross morphology. However, defining malignancy as any PVC increases sensitivity but lowers specificity—particularly in papillo-mas—whereas limiting malignancy to narrow-angle PVC improves specificity but risks false negatives and reduced reproducibility. Methods: We intraoperatively evaluated 146 histology-proven vocal-fold lesions using NBI-CE. Six raters (three experienced otolaryn-gologists, three PhD students) classified vascular patterns. Two approaches were tested: (1) malignancy = narrow-angle PVC; (2) malignancy = any PVC. Outcomes were accuracy, sensitivity, specificity, and interrater agreement. Results: Approach (1) had higher speci-ficity but lower sensitivity than (2) (~85% vs ~70% specificity; ~50% vs ~80% sensitivity). Accuracy did not differ significantly. Experienced raters showed higher interrater agree-ment and a more favorable sensitivity–specificity balance. Common errors were false pos-itives in papillomas and false negatives in dysplasia/early carcinoma. Conclusions: PVC assessment with NBI-CE is feasible and informative. Choosing between “any PVC” and “narrow-angle only” entails a sensitivity–specificity trade-off and depends on lesion type and experience. Refined ELS descriptors and automated analysis may improve reproduc-ibility and accuracy.