Coiling Sequences in Two-Stage Minimally Invasive Segmental Artery Coil Embolization

Objectives: Recently, minimally invasive staged segmental artery coil-&plug embolisation (MISACE) has been used in early clinical practice for spinal cord injury prevention prior to open or endovascular aortic aneurysm repair. Optimal sequencing for MISACE occlusion has not been investigated yet.

Methods: Twenty-five juvenile pigs were allocated into four groups. The first group had a two-stage MISACE sequence starting with occlusion of all lumbar segmental arteries in a first stage and the remaining thoracic segmental arteries in a second stage (N = 6). The second group received an alternating approach with occlusion of every second segmental artery in a first and the remainder in a second stage (N = 6). The third MISACE sequence started at the watershed area between thoracic level 12 to lumbar level 2 in a first and the remaining arteries in a second stage (N = 6). A control group of seven animals received complete, open segmental artery occlusion in a single stage. Neurological assessment, regional spinal cord tissue perfusion, and histological examination were performed.

Results: Permanent paraplegia in the MISACE groups was observed in one animal of group 2 (alternating sequence) and one animal from group 3 (watershed sequence). In the control group, 57% experienced permanent paraplegia. Group 1 (lumbar stage 1, remainder stage 2) did not experience permanent paraplegia with no significant tissue damage (p < 0.05 group 1 vs. control). Regional spinal cord tissue perfusion in group 1 recovered within 3 days after stage 2, whereas mean perfusion of the other groups remained significantly lower compared with baseline (all p < 0.05). Animals from group 3 (watershed) did not suffer from any neurological impairment after stage 1 MISACE with recovering regional perfusion after this stage; however, recovery was worse after the second stage.

Conclusion: Minimally invasive staged repair results in less ischemic spinal cord injury and favorable neurological outcomes compared with a one-stage approach. Although an occlusion sequence starting with the lumbar segmental arteries in a first stage seems to be the best two-stage approach with regard to neurological outcome and regional spinal cord perfusion, an alternative approach starting with the watershed area in a first stage and continuing the MISACE procedure in a second, third, or fourth stage may also yield favorable results.