Safe, Algorithmic Prostatic Artery Embolization: Collateral Protection and Non-Target Avoidance Including the Pena-Collateral Spear Technique

Learning Objectives: (1) Map penile–perineal collateral pathways relevant to non-target risk in prostatic artery embolization (PAE). (2) Apply a stepwise algorithm for selective catheterization, protection, and embolic delivery that minimizes reflux and non-target flow. (3) Describe indications, setup, and execution of the Pena-Collateral Spear technique within the algorithm, and recognize digital subtraction angiography (DSA) and cone-beam CT (CBCT) pitfalls.

Background: BPH affects up to 50% of men over age 60 and can cause lower urinary tract symptoms, recurrent infections, and impaired quality of life. Standard treatment includes medical therapy and surgical resection, but surgery carries risks of bleeding, sexual dysfunction, and prolonged recovery. PAE has emerged as a minimally invasive alternative; however, variable pelvic anatomy and penile–perineal collaterals increase the risk of non-target embolization.

Clinical Findings/Procedure Details: Preprocedure evaluation includes symptom scoring, prostate sizing, and collateral mapping with cross-sectional imaging, complemented by diagnostic DSA and CBCT for refined anatomy. Radial or femoral access with a 5–6F guide and high-trackability microcatheters is used, and anti-reflux strategies are considered in high-risk cases. The workflow involves systematic identification of prostatic artery origins and collateral pathways to pudendal, penile, rectal, and vesical branches. A DSA/CBCT checkpoint ensures distal microcatheter position beyond hazardous takeoffs before embolization, enabling either superselective targeting or temporary protection. The Pena-Collateral Spear technique provides focused protection for penile/perineal collaterals through image-guided needle occlusion at the midline collateral adjacent to the anterior prostate, with confirmation of flow arrest on DSA/CBCT prior to embolic delivery. Embolization is performed in slow, staged fashion with repeat imaging when uncertainty exists. Post-embolization angiography confirms prostate devascularization and absence of non-target filling, with predefined stop criteria addressing reflux, vasospasm, or misdirected flow.

Conclusion and/or Teaching Points: A collateral-first workflow with CBCT checkpoints enhances safety and reproducibility in PAE. Incorporating the Pena-Collateral Spear technique neutralizes hazardous penile and perineal collaterals. Systematic checkpoints and predefined stop criteria reduce non-target events and support broader adoption of PAE across variable pelvic anatomies.