Two Nacogdoches County men are recovering from delicate surgeries in Tyler. They were driving all terrain vehicles that hit head on. Christopher Christian, 21, was on a four wheeler. His 17 year old cousin Adam Stripling was on a three wheeler. Niether vehicle had lights when they collided on darkened County Road 711, off FM 225. The accident happened around 10:00 Thursday night. Christian's mother says her son underwent a two hour brain surgery Friday morning. Doctors say the next three to four days are critical to his recovery. She says Stripling had reconstructive surgery and is expected to recover despite severe injuries.