The interventional procedure is a new treatment modality that treats specific disease via percutaneous, minimally invasive manipulation using various devices such as a guidewire, catheter, balloon, and stent under the various imaging modalities such as ultrasound, fluoroscopy (X-ray radiography), computed tomography and magnetic resonance image. It does not need a large surgical incision. Its advantages include reduced bleeding due to a minimal skin incision, rapid patient recovery, and few possible complications because of local rather than general anesthesia. It is classified as nonvascular and vascular procedures (Fig.1)[1].

The vascular interventional procedure is used for treatment of arterial and venous diseases and cancers. The technique involves access to the target organ by percutaneous insertion of a catheter of 1-7 mm diameter through blood vessels under ultrasound or fluoroscopic guidance. The vascular interventional procedure can be applied to liver tumors, arterial bleeding, various vascular occlusion or stenosis, uterine fibroid embolization, and its scope of application is currently expanding.

Fine medical device manufacturing made possible by the development of precision machining technology has led to several advances in medical devices for interventional procedures. Introducer catheter or sheath, catheter, and guide wire are the basic devices of the technique, which have the purpose of injecting contrast agent to a desired blood vessel for diagnostic angiography. Devices for treatment include catheter for radiofrequency ablation, stent, and balloon catheter and are modified such that an electrode is attached to the catheter tip, the stent is mounted on the inside, or a balloon is attached to the middle part, respectively (Fig.2)(Table 1) [2].

After puncturing the vessel under an ultrasound guidance or by palpating the artery, an introducer catheter is inserted and fixed to protect the blood vessel from trauma. After the guide wire and catheter are inserted as shown in the Figure 3, catheter and guide wire are navigated to select the target vessel. The direction of the guide wire is determined by the rotation along the angulation of the blood vessels. Subsequently, the catheter (usually 5 French=1mm in out-diameter) is inserted or rotated along the guide wire, and the process is repeated until reaching the target vessels. In order to reach a smaller vessel, a catheter with a 3-French smaller diameter (microcatheter) and a microguide wire are inserted inside of the main 5-French catheter, and the direction is determined by the insertion and rotation of the guide wire for microcatheter as with the catheter; and the microcatheter is then inserted along the guide wire. Finally, angiography is performed or the therapeutic drug is delivered by injecting the contrast agent or drug through the catheter or the microcatheter after removing the guide wire [34].

1. Mechanism and control system: The vascular intervention robot usually adopts a master-slave robot system to keep the operators away from the radiation. It also needs systems to control the guide wire and catheter separately. The systems which can use both the 5 F catheter and the 3 French microcatheter simultaneously are now under development.

2. Image integration and navigation: Conventional vascular intervention is performed under 2-dimensionl angiographic imaging. Operators have to reconstruct 3-dimensional images according to subjective anatomy-based experience. For safer and more accurate procedure, integrated display of the intervention device and 3-dimensional vascular image are mandatory.

3. Haptic force-feedback: To assure the safety of remote operating systems of the procedure, it is important to have haptic force-feedback transmitted to the operator's hand on real time. So far, haptic technology is not adapted in current commercialized systems.

The vascular interventional procedure robotic system has progressed from developmental to commercialization stage. However, it is not actively applied to clinical procedures, and the number of products under research is also limited.

The vascular interventional procedure robotic system approved by the US Food and Drug Administration (FDA), Hansen's Magellan Robotic Catheter System has been developed and commercialized [11]. Despite its limitations, this system is already applied in clinical procedures. A recent report indicates its successful use in the Endovascular Aneurysm Repair (EVAR) procedure [12], with only 5 minutes in setup time and 3 minutes in selection of the left renal artery. In addition, this system was reportedly used for the treatment of venous disease in collaboration with Da Vinci robotic surgery that is applied worldwide [13]. The End-effector Magellan system is configured with introducer catheter of maximum 9 French diameter and catheter assembly of maximum 6.1 French diameter, with no significant difference in the catheter used for the actual manual interventional procedure. The catheter can bend 180 degrees and is very advantageous in the vessel selection. However, the coverage is very limited since it is > 1 mm, a 3F sized catheter is required in a variety of vascular interventions, in particular hepatic artery intervention. In addition, there are high limitations of use in the surgical field, due to development as a fully automated system and disadvantage of high cost.

We are developing a vascular interventional robotic system which uses the conventional 5-French catheter system that is currently used in the angiography room. The advantage is the possibility of direct application to the field without the need to replace the existing procedure equipment. The final system should be an affordable, reduced sized, semi-automatic system in which only the procedure with high radiation exposure is automatically implemented and the rest is processed manually (Fig.5).

Master-slave vascular intervention robot is a new emerging field in the era of vascular intervention. This approach can drastically reduce radiation exposure by replacing human effort by a robotic system for high radiation exposure procedures. The movement and the trajectory of the robot can be memorized and quantified on the computer so that the procedure can be repeated fast and safely. Further studies to upgrade the current systems and to prove the clinical benefits over the conventional intervention are required.