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A novel technique combining laparoscopic and endovascular approaches using image fusion guidance for anterior embolization of type II endoleak

Type II endoleak (T2E) leading to aneurysm sac enlargement is one of the challenging complications associated with endovascular aneurysm repair. Recent guidelines recommend embolization of T2E associated with aneurysmal sac enlargement. Various percutaneous and endovascular techniques have been reported for embolization of T2E. We report a novel technique for T2E embolization combining laparoscopic and endovascular approaches using preoperative image fusion. We believe our technique provides a more direct access to the lumbar feeding vessels that is typically challenging with transarterial or translumbar embolization techniques.

Type II endoleak (T2E) leading to aneurysm sac enlargement is one of the challenging complications associated with endovascular aneurysm repair. Recent guidelines recommend embolization of T2E associated with aneurysmal sac enlargement. Various percutaneous and endovascular techniques have been reported for embolization of T2E. We report a novel technique for T2E embolization combining laparoscopic and endovascular approaches using preoperative image fusion. We believe our technique provides a more direct access to the lumbar feeding vessels that is typically challenging with transarterial or translumbar embolization techniques. (J Vasc Surg Cases and Innovative Techniques 2017;3:7-10.) Type II endoleak (T2E) is the most common endoleak complication associated with endovascular aneurysm repair (EVAR). 1 The prevalence of T2E has been reported to be between 10% and 25%. 2,3 Recent guidelines suggest intervention when T2E is associated with aneurysmal sac growth. 4 Various percutaneous and endovascular treatment strategies have been described for the management of T2E. 5 T2E especially from lumbar artery feeders can be difficult to embolize by conventional translumbar or transarterial approaches, mainly because of their location and trajectory, posing challenges with imaging, positioning of the patient, and access. Transcaval access and perigraft access from the distal landing zone into the aneurysm sac ("transealing") have also been reported. [6][7][8] Recently, laparoscopic clipping or ligation of inferior mesenteric and lumbar artery feeders has also been used for the management of T2E. [9][10][11] The purpose of this study is to report a novel technique of laparoscopically directed anterior embolization (LDAE) using preoperative image fusion guidance for management of T2E.

CASES
We report two cases of T2E from lumbar arteries treated with LDAE using preoperative computed tomography (CT) angiography-fluoroscopy image fusion. Both patients consented to the publication of this article.

Patient 1
A 97-year-old man with chronic kidney disease (CKD; baseline creatinine concentration of 3 mg/dL) was found to have a 9.3-cm aneurysm sac and a T2E 3 years after EVAR. The posterior orientation of the lumbar feeding vessels and the patient's CKD rendered a prolonged transarterial or translumbar attempt undesirable. This along with an increase in aneurysm size of 0.5 cm in 1 year prompted us to intervene. LDAE provided the most direct access to the target vessels (Fig 1).

Patient 2
An 87-year-old woman presented 2 years after EVAR with a T2E from lumbar arteries. Increase in aneurysm size of 0.7 cm in 1 year and failed translumbar and transarterial embolization attempts led us to use LDAE, providing direct access to target the posteriorly located feeding lumbar (Fig 2).

DISCUSSION
Recent guidelines recommend treatment of T2E with aneurysmal sac enlargement. 4 Baum et al and Aziz et al showed failure rates of 80% and 72% after conventional transarterial and translumbar embolization, questioning the long-term efficacy of these techniques. 5,12 Posterior endoleaks are difficult to embolize using the translumbar approach because of the challenge of cannulating the lumbar vessels while maintaining sac access, often requiring a 180-degree catheter turn after translumbar access. Whereas the right-sided translumbar approach might be technically feasible for leftsided lumbar feeders, there is an added risk of inferior vena cava injury. Another consideration with translumbar embolization is the prone position, which might not be tolerated by some patients. Laparoscopic clipping of inferior mesenteric and lumbar arteries as a durable treatment option has been reported. 1,9,10 On the other hand, this approach carries additional risk of injury to nearby structures during dissection around the aneurysm sac. 1 Both our patients tolerated the LDAE and were subsequently discharged home. Repeated imaging 3 to 5 months after embolization did not show any evidence of endoleak, and both patients did not have any laparoscopy-related complications.
LDAE is a novel technique in which preoperative 3D image fusion has been used for better anterior access to the feeding vessels, especially lumbar artery feeders. It also provides us with a trajectory to avoid hitting the endograft but at the same time allows us an easy angle with which to work. In one of the cases, we crossed in between the two limbs of the endograft. Both of our patients were older than 85 years and tolerated the procedure well. Although this technique is still in its infancy, we think it provides a better and a more direct anterior approach with minimal laparoscopic dissection around the sac. This procedure can be considered in elderly patients and obese patients to avoid prone positioning, in patients with CKD, and in those for whom other embolization techniques have failed. The objective of this manuscript is to illustrate LDAE as an alternative option, and it is not our first line of therapy currently. One obvious limitation of LDAE is that it requires familiarity with laparoscopic techniques and 3D image fusion. Carbon dioxide insufflation during LDAE can potentially affect the accuracy of image fusion; however, in these two cases, the inflation pressures were kept low during 3D acquisition and image guidance. In addition, carbon dioxide insufflation during LDAE was performed mainly during the initial sac access step to deflect the intervening bowel and related structures and did not considerably affect the position of target vessels on switching to embolization.
CONCLUSIONS LDAE provides a more direct anterior approach to lumbar vessel feeders that is typically not achieved with translumbar or transarterial approaches. Irrespective of T2E access, such laparoscopic techniques under preoperative CT and MR image fusion guidance could potentially provide a novel platform for combining the advantages of laparoscopy with minimally invasive endovascular procedures.