Microcatheter Shaping for Double J Curve Configuration
The most effective method for creating a double J curve in a microcatheter is using 3D-printed patient-specific vessel models combined with heat-based shaping at 50°C for 5 minutes, which provides superior precision, stability, and procedural efficiency compared to traditional manual shaping methods. 1, 2
Primary Shaping Technique: 3D Printing-Assisted Method
The optimal approach involves creating a hollow, translucent 3D-printed model of the patient's specific vascular anatomy using CT angiography data, then immersing both the model and microcatheter in water heated to 50°C for 5 minutes. 2 This technique allows the microcatheter to conform precisely to the patient's actual vessel geometry, including complex double J configurations. 1
Step-by-Step Protocol
Pre-procedural planning: Obtain Digital Imaging and Communication in Medicine (DICOM) data from cerebral angiography and create a 3D-printed acrylic resin or flexible hollow model of the target vessel anatomy. 3, 2
Heat-based shaping process: Place the unshaped microcatheter into the 3D model immersed in water, heat to 50°C, and maintain for 5 minutes to achieve stable shape memory. 2
Sterilization: Sterilize both the shaped microcatheter and the 3D vessel model (using plasma sterilization for the model) before the procedure. 3
Intra-procedural reference: Keep the sterilized 3D model available in the sterile field for real-time comparison and potential reshaping if needed. 3
Alternative Method: Intravascular Placement Shaping
For situations where 3D printing is unavailable, the SL-10 straight microcatheter can be shaped using intravascular placement by inserting it into the parent artery for 5 minutes to acquire the vessel's natural curve. 4, 5 This technique is particularly effective for vertebrobasilar aneurysms where tortuous anatomy makes traditional shaping difficult. 4
Intravascular Shaping Protocol
Initial placement: Insert an unshaped SL-10 straight microcatheter into the parent artery until the tip passes through the aneurysm neck. 5
Dwell time: Leave the microcatheter in contact with the vessel wall for exactly 5 minutes, as shape stabilization occurs at this timepoint. 5
Shape verification: Remove the microcatheter and compare the acquired shape with three-dimensional rotational angiography to confirm anatomical match. 5
Tip refinement: After acquiring the shaft curve, perform additional steam shaping of the microcatheter tip according to the long axis of the target aneurysm. 4
Clinical Outcomes and Efficiency
The 3D printing method demonstrates superior performance with 93.75% technical success, automatic navigation without microguidewire assistance in most cases, and only 19% requiring shape modification. 3, 1 This compares favorably to traditional manual shaping methods, which require more frequent adjustments and longer procedure times. 1
Procedural advantages: The 3D shaping method significantly reduces overall procedure time, decreases the number of coils deployed, and minimizes catheter repositioning due to kickback (only 29% require repositioning). 3, 1
Safety profile: No procedure-related complications, including aneurysm rupture, have been reported with either 3D printing or intravascular shaping methods. 3, 4
Microcatheter Selection Considerations
Contemporary coronary microcatheters with kink-resistant metallic braids are preferred over over-the-wire balloons because they provide superior fluoroscopic visualization with distal tip markers, lower profiles, and better wire-to-lumen ratios. 6 The SL-10 straight microcatheter demonstrates the highest shapability among tested catheters and most readily acquires vessel geometry. 5
Common Pitfalls and How to Avoid Them
Insufficient dwell time: Shape memory stabilizes at 5 minutes for intravascular shaping; shorter durations result in incomplete shape acquisition and potential rebound. 5
Inadequate temperature control: Water temperature must reach exactly 50°C for optimal heat-based shaping; lower temperatures produce unstable shapes. 2
Ignoring patient-specific anatomy: Generic pre-shaped catheters often fail in complex double J configurations; always use patient-specific shaping methods for tortuous anatomy. 4, 1
Premature catheter advancement: When using intravascular shaping, ensure the microcatheter tip passes completely through the aneurysm neck before the 5-minute dwell period begins. 5