BACKGROUND AND PURPOSE:The flow-diverter stent has been proved a feasible, safe, and efficient technique, particularly for the treatment of large and broad-neck carotid siphon aneurysms. Wide-neck bifurcation aneurysms remain, in some cases, a challenge for neurointerventionalists. We report the outcomes of the treatment of saccular middle cerebral artery bifurcation aneurysms with flow diversion in our institution.

The dorsal scapular artery (DSA) can be either a direct branch of the subclavian artery (SCA), or a branch of the transverse cervical artery (TCA). In mandibular reconstruction, when a free flap is contraindicated a pedicled scapular flap has been described vascularized by the DSA. During the dissection of this flap, there is a risk of lesion of the TCA, which could be fatal to the flap if the DCA is a branch of the TCA. To evaluate the frequency of this anatomic situation, a dissection and radiologic study has been performed. 50 anatomic dissections on fresh cadavers and 93 arteriographies from 47 patients have been studied, to determine what was the DSA origin. In our dissections we found the origin of the DSA was a type I origin in 19 cases (38 %), a type II in 19 cases (38 %) and a type III in 12 cases (24 %). In our radiologic study, the DSA and the TCA had a common origin from the SCA (Type I) in 57/93 cases (61.3 %), the DSA was a direct branch of the SCA and the TCA (type II) in 22/93 cases (23.7 %), the DSA and the TCA had a common origin from the TCT (type III) in 14/93 cases (15 %). The DSA is coming from the TCA in 1/5 cases. A careful dissection of this flap in the subclavian area is necessary in all cases, a preoperative arteriography could be proposed to limit the risk of pedicle injury.

In our experience, covering the PComA by FDS when treating carotid siphon aneurysms appeared safe and the P1/PComA ratio is a good predictor of flow changes in PComA.