This study describes a case of traumatic carotid-cavernous fistula poorly treated with balloons and rescued by coils through a PComA approach. A six-year-old boy suffered a left temporal bone puncture wound. Digital subtraction angiography disclosed a left carotid cavernous fistula. Five balloons were implanted into the cavernous sinus and the parent artery was sacrificed unwillingly, but the residual fistula retro-engorged by the ophthalmic artery communicated with the maxillary artery and the post circle through the PComA. We finally occluded the residual fistula through the PComA with coils. Once the parent artery was sacrificed and the distal residual fistula still retro-engorged, another patent communicating artery may be a rescue approach.