💉 Pudenz Cardiac Catheter

The 'Pudenz cardiac catheter' is a specialized component of early cerebrospinal fluid shunt systems, designed for ventriculoatrial shunting in patients with hydrocephalus. It facilitates distal diversion of CSF into the right atrium of the heart.

• Made of silicone or polyurethane
• Radiopaque tip to confirm positioning under fluoroscopy
• Side perforations to facilitate CSF entry and reduce obstruction risk
• Often attached to a Pudenz-type valve system

• Component of VA shunt systems
• Guides CSF flow from subcutaneous tunnel to right atrium
• Typically inserted via the internal jugular vein or subclavian vein
• Tip positioned in the right atrium, verified radiologically

• Developed as part of Pudenz-Heyer valve systems in the 1950s–60s
• Widely used before peritoneal approaches became standard
• Still referenced in cases requiring atrial drainage (e.g., peritoneal absorption failure)

• Arrhythmias (due to intracardiac catheter presence)
• Venous thrombosis or pulmonary embolism
• Shunt nephritis (immune complex deposition in kidneys)
• Catheter migration or fracture
• Requires lifelong cardiac imaging surveillance

• Ventriculoperitoneal (VP) shunts: now first-line due to lower systemic risks
• Ventriculopleural or lumboatrial shunts in select cases

• Pudenz RH, Sheldon CH. (1951). “The surgical treatment of hydrocephalus: an experimental study.” *J Neurosurg*.
• Drake JM. (1995). “Shunt technology: 30 years of progress.” *Child’s Nerv Syst*.
• Rekate HL. (2008). “A contemporary definition and classification of hydrocephalus.” *Semin Pediatr Neurol*.

🧠 Though largely historical, the Pudenz cardiac catheter remains a relevant concept in neurosurgical history and in rare cases requiring ventriculoatrial shunting today.

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In a Retrospective comparative cohort study Massimi et al. addressed children undergoing VAS in the 2020-2022 period at a single Institution. Patients receiving VAS with Pudenz cardiac catheter (distal slit “valves”) were assigned to group A (2020-2021) while those with VAS harboring proximal adjustable valve to group B (2021-2022, Pudenz no more available). The complications leading to shunt malfunction within 2 years from VAS were analyzed.

Twenty-four children belonged to group A (M/F ratio: 2.4; mean age: 42.5 months) and 18 to group B (MF/ratio: 1.8, mean age: 48.1 months). Statistically significant differences were found about: 1) patients needing shunt revision: 7 cases (29%) in group A vs. 11 cases (61%) in group B; 2) number of shunt revisions: 8 in group A vs. 16 in group B; 3) number of children with mechanical complications: 2 (8.3%) in group A vs. 7 (39%) in group B; 4) number of mechanical complications: 2 (group A) vs. 9 (group B). No differences in other complications or placement-to-revision time were detected.

The lack of simple surgical tools (Pudenz catheter) may make VAS more prone to mechanical complications. Prospective and multicenter trials are needed to produce scientific evidence. In the meantime, a multidisciplinary discussion on the European regulation (including Doctors and Manufacturers) is welcome. ¹⁾

The authors investigate the clinical consequences of the withdrawal of the Pudenz cardiac catheter, a simple distal component used in ventriculo-atrial shunts (VAS), due to European regulatory changes. They compare outcomes in children who received VAS with Pudenz catheters (Group A, 2020–2021) versus those who received alternative shunt systems with proximal adjustable valves (Group B, 2021–2022).

✅ Strengths Topical Relevance: The study tackles the unintended clinical consequences of new European medical device regulations (MDR 2017/745), a rarely quantified but highly important topic.

Clinical Significance: The findings are directly tied to patient safety, especially in a vulnerable pediatric population.

Clear Outcomes: The endpoints—shunt revisions and mechanical complications—are objective, measurable, and clinically meaningful.

Comparative Design: Despite being retrospective, the study design facilitates a temporal comparison between pre- and post-regulation cohorts.

⚠️ Limitations Retrospective and Single-Center Design Limits internal validity and generalizability. No control for confounding variables such as surgeon experience, comorbidities, or technique variation.

Small Sample Size Only 42 children (24 in Group A, 18 in Group B) were included. This limits statistical power and may increase the chance of both Type I and Type II errors.

Device Heterogeneity in Group B While Group A exclusively used the Pudenz catheter, the exact specifications of the adjustable valve system in Group B are not detailed. Differences in valve type or distal tubing may independently influence complication rates.

Short Follow-up Window A two-year follow-up may not capture long-term complications such as shunt infection, central venous thrombosis, or late catheter migration.

No Adjustment for Confounders The analysis is unadjusted. Factors like patient comorbidities, ventricle size, venous anatomy, and surgeon-specific practices could confound the observed differences.

🔎 Interpretation of Results The study found significantly higher complication and revision rates in Group B:

Shunt revision rate: 29% vs. 61%

Mechanical complications: 8.3% vs. 39%

These findings suggest that the removal of a simple and effective tool (the Pudenz catheter) may have introduced mechanical vulnerabilities into the VAS procedure. However, the observational nature and limited sample size preclude strong causal inference.

🏛️ Regulatory Implications The study serves as a cautionary example of how well-intentioned regulations may inadvertently disrupt clinical practice without a scientific basis for device removal. It calls for:

Multidisciplinary regulatory dialogue, involving neurosurgeons, manufacturers, and policymakers.

Scientific oversight of device discontinuation decisions.

Bridging clinical evidence and regulatory pathways to prevent similar gaps in care.

📌 Conclusion Massimi et al. present an important early warning about the clinical fallout from rigid regulatory transitions. While the data are preliminary and hypothesis-generating, the findings highlight the critical need for clinical evidence to guide device policy. Until larger prospective studies are done, the neurosurgical community and regulators must collaborate to ensure evidence-based decision-making in pediatric device availability.