Louis-Martin Boucher

Background/Objectives: Poiseuille’s law describes the influence of radius, length, viscosity, and pressure on the flow of Newtonian fluids. Although bone cement is a non-Newtonian, shear-thinning, and polymerizing material that does not comply with this law in any predictive or quantitative sense, its qualitative principles may offer a didactic framework for understanding factors that affect injectability during cementoplasty. The objective of this Technical Note is to provide an educational and conceptual interpretation of Poiseuille’s law as it relates to trocar selection, cement behavior, and procedural planning. Methods: This work presents theoretical calculations based on the r⁴/L component of Poiseuille’s equation, using manufacturer-specified internal radii for commonly used trocars. Relative flow rates were computed as r⁴/L ratios normalized to a 13-gauge, 15 cm trocar. Conceptual viscosity profiles illustrate qualitative differences among cements over time. A representative, fully anonymized clinical example is provided to illustrate the integration of these conceptual principles into practice. No experimental measurements were performed. Results: Theoretical calculations show that trocar radius has the strongest influence on theoretical flow, with an exponential effect (r⁴), whereas increasing trocar length proportionally reduces flow. Conceptual viscosity curves demonstrate the rapid rise in viscosity during polymerization and highlight the importance of timing and cement selection. The clinical example illustrates how trocar choice, access planning, and cement viscosity are adapted to lesion morphology and cortical integrity. Conclusions: Poiseuille’s law cannot model or predict bone cement behavior and has no procedural or clinical validity in cementoplasty. Its use in this Technical Note is strictly educational, providing a qualitative framework to illustrate general relationships between equipment characteristics, viscosity evolution, and resistance during injection, without offering clinical guidance or implying any impact on procedural planning, safety, or outcomes.

We describe the case of a moderately long chronic superior mesenteric vein (SMV) occlusion following Whipple procedure. Anticoagulation therapy and traditional recanalization techniques through retrograde approach, collateral inferior mesenteric venous vasculature, and recanalization upstream of the SMV occlusion via direct transabdominal puncture failed. Sharp recanalization downstream of the occlusion via retrograde approach, using the stiff end of a glidewire sharpened with a blade, with guidance from the tip of a catheter placed upstream of the occlusion as a target was successful. Our rendezvous technique, combined with use of orthogonal views, allowed for increased precision and decreased risk of catastrophic extravasation.

Introduction: Benign prostatic hyperplasia is a prevalent disease that could be responsible of severe intractable hematuria requiring invasive surgical management. Case presentation: We report three high-risk cases presented with intractable hematuria of prostatic origin with high medical co-morbidities treated safely and effectively by prostatic artery embolization with favorable outcomes. Conclusions: In non-surgical, anticoagulated patients, prostatic artery embolization represents a safe and effective intervention for the treatment of intractable hematuria related to benign prostatic hyperplasia.

Supplementary Table 1 shows the clinical characteristics of the patients from whom patient-derived xenografts were generated and evaluated in the preclinical trial

Supplementary Figure 2 shows the results of a pilot monotherapy trial to evaluate regimen-related toxicity