Radial/Snuffbox Access for Neuroendovascular Procedures

In summary, the radial or snuffbox approach for neuroendovascular procedures has evolved from its origins in interventional cardiology in the early 1990s to its current application in neurointervention.

1. Transradial access in cardiology: The radial approach was first popularized in the field of interventional cardiology in the early 1990s. Dr. Lucien Campeau performed the first coronary angiography using the radial artery in 1989, and Dr. Ferdinand Kiemeneij performed the first transradial coronary angioplasty in 1992. The radial artery’s superficial location and fewer complications, such as bleeding and vascular injury, made it an attractive alternative to the traditional femoral artery approach.
2. Adaptation to neurointervention: As the radial approach gained acceptance in cardiology, it began to be explored as an option for neuroendovascular procedures. In the early 2010s, several case series and reports were published demonstrating the feasibility and safety of the radial approach for diagnostic cerebral angiography and endovascular treatments, including coiling of intracranial aneurysms and carotid artery stenting.
3. Snuffbox approach: The anatomical snuffbox, located in the wrist’s dorsal aspect, is another potential access point for the radial artery. This approach was first reported for coronary angiography and interventions in the late 2010s. Subsequently, its use in neuroendovascular procedures has been described in case reports and small series, showing promising results in terms of safety and efficacy.
4. Growing evidence and adoption: Over the past decade, the radial and snuffbox approaches have gained increasing attention in the field of neurointervention. Numerous studies have demonstrated the advantages of these approaches, including reduced access site complications, faster ambulation, and increased patient comfort. As a result, more neurointerventionalists are incorporating the radial and snuffbox approaches into their practice.

The radial approach has gained popularity in neuroendovascular procedures due to several advantages compared to the traditional femoral access. Some of the key benefits of using the radial artery in the wrist as an access point for these procedures include:

1. Lower risk of access site complications: The radial approach is associated with a lower risk of bleeding, hematoma, and pseudoaneurysm formation at the access site compared to the femoral approach. This is primarily due to the radial artery’s superficial location, making it easier to achieve hemostasis after the procedure.
2. Enhanced patient comfort: Patients undergoing neuroendovascular procedures via the radial approach can often sit up and ambulate more quickly after the procedure than those with femoral access. This can lead to improved patient comfort and satisfaction, as well as potentially shorter recovery times and hospital stays.
3. Reduced risk of retroperitoneal hematoma: The radial approach eliminates the risk of retroperitoneal hematoma, a rare but potentially serious complication associated with femoral access.
4. Suitable for patients with challenging femoral access: In some patients, femoral access may be difficult or contraindicated due to factors such as obesity, severe peripheral arterial disease, or previous groin surgery. In these cases, the radial approach can offer an alternative access route for neuroendovascular procedures.
5. Lower infection risk: The risk of infection at the puncture site is generally lower with the radial approach than with femoral access, partly because the wrist is less prone to contamination than the groin area.
6. Reduced radiation exposure to the operator: Some studies have suggested that the radial approach may result in less radiation exposure to the interventionalist during the procedure, as the operator’s hands are farther from the X-ray source compared to the femoral approach.

Despite these advantages, the radial approach may have some limitations, including a longer learning curve for the operator, potential radial artery spasm, and challenges in navigating tortuous or small radial arteries. It is essential to consider individual patient factors and the operator’s experience when choosing the most appropriate access route for neuroendovascular procedures.

The rate of conversion from radial to femoral access during neuroendovascular procedures can vary depending on the specific patient population, the experience of the interventionalist, and the complexity of the procedure. In the literature, the reported conversion rates range from around 5% to 15%. It is important to note that these rates may vary depending on the factors mentioned above.

Conversion from radial to femoral access may be necessary due to various reasons, including radial artery spasm, small or tortuous radial arteries, difficulty navigating through the subclavian and brachiocephalic arteries, or inability to select the target vessels with the available radial catheters and devices.

As the experience and expertise with the transradial approach for neuroendovascular procedures continue to grow, the conversion rates may decrease. Moreover, the development of new devices and techniques specifically designed for radial access may further improve the success rates and reduce the need for conversion to femoral access.

While the transradial approach for neuroendovascular procedures is generally considered safe, there are potential risks and complications associated with it. The exact percentages of these risks can vary among patient populations, the experience of the interventionalist, and the specific procedure being performed. Here are some common risks associated with the transradial approach and their approximate incidence rates based on the available literature:

1. Radial artery spasm: This is one of the most common complications, occurring in about 5-15% of cases. It can cause discomfort to the patient and may necessitate conversion to femoral access.
2. Access site hematoma: Hematoma formation at the puncture site is generally less frequent with the radial approach compared to femoral access, with an incidence rate of around 1-5%.
3. Radial artery occlusion: This complication, characterized by the complete blockage of the radial artery, occurs in about 1-5% of cases. It is often asymptomatic and may resolve spontaneously, but in some cases, it can lead to ischemic complications.
4. Difficulty with catheterization or device navigation: In some cases (approximately 5-15%), the interventionalist may encounter challenges navigating the catheter or device through the radial artery and the aortic arch, requiring conversion to femoral access.
5. Pseudoaneurysm or arteriovenous fistula: These complications are relatively rare with the radial approach, with incidence rates of less than 1%.
6. Local nerve injury: Although uncommon, nerve injury can occur in less than 1% of cases, potentially causing temporary or permanent sensory or motor dysfunction.
7. Ischemic complications: The risk of hand ischemia is rare (<1%) but can occur if there is inadequate collateral circulation between the radial and ulnar arteries.