Steerable sheath: a precise and controlled vascular intervention tool

In modern medicine, minimally invasive surgery and interventional therapy have become important means of diagnosis and treatment of many diseases. In order to improve the accuracy and safety of surgery, medical equipment is also constantly innovating. Among them, the steerable sheath, as a new type of interventional tool, is gradually changing the operation mode of traditional surgery due to its unique design and excellent performance.

What is a steerable sheath?
A steerable sheath is a medical device with adjustable distal bend. Its core feature is that the angle of the sheath end can be adjusted in vitro, so that it can point to a precise position in the patient's body to adapt to different anatomical structures. This design allows doctors to more flexibly guide other instruments into the target area during surgery without relying on complex guidewires or multiple attempts.

Compared with traditional sheaths, the biggest advantage of steerable sheaths is their adjustability and controllability. It is usually composed of multiple layers of materials, including an outer braided structure, a middle reinforcing rib, and an inner layer of low friction coefficient materials (such as PTFE) to ensure good anti-kinking, pushing performance and tissue compatibility during operation.

What is the difference between a sheath and a catheter?
Before discussing the steerable sheath, it is necessary to understand the difference between it and the catheter in order to better understand its positioning and function in medical treatment.

Sheath is mainly used to establish and maintain a channel so that other instruments (such as guidewires, catheters, biopsy needles, etc.) can enter the body smoothly. Sheaths are usually thicker than catheters, have a certain hardness and stability, and can protect the blood vessel wall or cavity from damage. In interventional surgery, sheaths are often used to guide the catheter into the target site and help the catheter withdraw after the operation is completed to avoid additional damage to the tissue.

Catheters are mainly used to transport liquids, gases or drugs, such as contrast agents, blood, drugs or nutrient solutions. Catheters are usually slender, soft and easy to bend, suitable for occasions requiring delicate operations, such as cardiac catheters, infusion catheters, etc.

Therefore, the sheath is the "shell" or "channel" of the catheter, and the catheter is the "working tool" that enters the body through the sheath. The emergence of steerable sheaths is precisely to provide more stable and precise guidance support during catheter operation.

How does a steerable sheath work?
The working principle of a steerable sheath is based on the design of traction wire and reinforcement ribs. Its core structure includes:

Traction wire: located inside the sheath, controlled by the sliding device on the handle, the bending direction and angle of the end of the sheath can be adjusted.

Reinforcement rib: set inside the sheath to locate the bending direction of the tube body, so that the sheath can adaptively adjust the bending to conform to the complex vascular system of the human body.

Braided structure: enhances the torsion control ability of the sheath to prevent kinking during operation, while improving its torsion resistance and pushing performance.

Round tip: reduces damage to tissues and is suitable for operations on sensitive parts such as blood vessels and nerves.

PTFE inner layer: reduces the friction coefficient, allowing other instruments (such as guide wires and catheters) to pass easily and improve the smoothness of operation.

In actual operation, the doctor can control the traction wire through the handle to bend the end of the sheath to the desired angle, thereby guiding the catheter into the target area. This design not only improves the accuracy of the operation, but also reduces the dependence on X-rays and reduces the risk of surgery.

Due to its high precision and good maneuverability, steerable sheaths have been widely used in many medical fields, including:

Neurointervention: used for cerebral angiography, stent implantation, aneurysm embolization and other surgeries.

Cardiac intervention: used for coronary angioplasty, heart valve replacement and other surgeries.

Vascular intervention: used for peripheral angioplasty, thrombus removal, filter implantation and other surgeries.

Tumor intervention: used for tumor embolization, chemotherapy drug infusion and other surgeries.

In these surgeries, steerable sheaths can help doctors locate and operate more accurately, reduce operation time, improve success rate, and reduce the incidence of complications.

As an innovative medical device, steerable sheaths are gradually changing the operation mode of traditional interventional surgery. It not only improves the accuracy and safety of the operation, but also provides doctors with a more flexible and controllable operating environment. With the continuous advancement of technology, steerable sheaths are expected to play an important role in more fields and bring better medical services to patients.