Use of Target Tetra with an understanding of its novel structure

Abstract

Background: Coil embolization for cerebral aneurysms is an important technique and is not likely to be replaced in the foreseeable future. Recently, the Target Tetra detachable coil (TTDC) has become available, thereby raising expectations for a safer embolization in small aneurysms. Based on our experience, we report the behavioral characteristics and effective utilization of TTDCs.

Methods: We analyzed 28 patients who underwent surgery using the TTDC for intracranial aneurysms between December 2023 and November 2024.

Results: Five cases were treated using the TTDC only. In four of five cases, the aneurysm height was <3 mm. In terms of complications, intraprocedural rupture occurred in two cases and thrombosis in two. None of the patients presented with delayed hemorrhage during the follow-up period.

Conclusion: The TTDC coils cluster at the tip of the microcatheter. Thus, effective embolization can be achieved by filling from the deeper available space. Based on the behavioral characteristics of TTDCs, it is not only beneficial as a finishing coil but also plays a role in filling. We believe that TTDCs may be a useful option for embolizing small aneurysms, including ruptured ones that were previously challenging to treat, and cases in which microcatheter stability are compromised.

Keywords: Cerebral aneurysm; Coil embolization; Target Tetra detachable coil.

Figure 1:

In the case of a ruptured anterior communicating artery aneurysm, the height, width, and neck size of the aneurysm were 2.7, 2.8, and 2.7 mm, respectively. (a) Angiography before embolization. (b) Attempted frame formation using Target Ultra 2.5 mm × 4 cm. Safe frame formation was not possible due to protrusion into the parent artery. (c) A 2.5 mm × 3.5 cm Target Tetra detachable coil (TTDC) was placed through the aneurysmal neck. (d) A 2.0 mm × 2.5 cm TTDC was implanted as the second coil. The aneurysm neck was packed tight. However, the aneurysm tip had a space (arrow). (e) Angiography after completing embolization. The aneurysm, including its tip, had disappeared.

Figure 2:

In the case of an unruptured internal carotid artery-paraclinoid medial-type aneurysm, the height, width, and neck size of the aneurysm were 3.0, 4.5, and 3.0 mm, respectively. (a) Angiography before embolization. The balloon catheter was seated on the aneurysm neck. (b) The frame was formed with the first coil. The arrow was a microcatheter tip. (c-f) The Target Tetra detachable coil (TTDC) was implanted deep inside the aneurysm. Each arrow was a gradual kicking back microcatheter tip. The TTDC sizes were 3 mm × 4.5 cm (c), 3 mm × 4.5 cm (d), 2.5 mm × 4.5 cm (e), and 2 mm × 2.5 cm (f). (g) Angiography after completing embolization. The aneurysm had disappeared.

Figure 3:

In the case of a ruptured vertebral artery-posterior inferior cerebellar artery aneurysm, the height, width, and neck size of the aneurysm were 3.7, 4.7, and 2.8 mm, respectively. (a) Angiography before embolization. (b) The first coil was implanted with Target 360 Ultra 4 mm × 8 cm. (c) The microcatheter tip perforated the aneurysm during the second coil, with a 3.5 mm × 6 cm Target Tetra detachable coil (TTDC). (d and e) A 2.5 mm × 6 cm TTDC was implanted from the outside of the aneurysm to the inside. However, bleeding was observed (arrow). (f and g) The last coil, which is a 2 mm × 2.5 cm TTDC, stopped the bleeding.