Driver impaled on post

A wooden post pierced Pereki Kaihau's shoulder after he fell asleep at the wheel and lost control of his car. Photo / Westpac Rescue Helicopter

A driver has made a "miracle" recovery after being impaled on a 3m fencepost that smashed through his windscreen after he fell asleep at the wheel.

Pereki Kaihau was airlifted to Middlemore Hospital in a critical condition with the post sticking out about 30cm either side of his lower left shoulder.

The wood pierced the window of his Honda Civic after he crashed into a paddock on Glenbrook Rd, South Auckland, missing his heart by "a whisker".

But the stevedore was discharged from hospital within a week - with his surgeon amazed by his good fortune.

The 20-year-old was driving from Manukau to Waiuku for league training when he nodded off about 2.30pm on March 3.

"I wasn't tired but I must have just closed my eyes for a second," he said.

"When I woke up the car was on its side and I was sliding. The car kept going and I just spun."

The wood went through the window, Kaihau's shoulder and his seat as the vehicle slid 50m across the paddock and down a bank. "When the car stopped I tried to move and couldn't," said Kaihau.

"I looked down at my shoulder and saw the piece of wood was in it. I realised it was right through me. I was pretty scared ... I thought I was going to die."

Motorists stopped to help and alerted emergency services.

One held the post steady while a passing doctor put a tourniquet on the shoulder.

Firefighters cut the roof from Kaihau's car so ambulance staff could administer morphine.

Pukekohe senior fire station officer Graeme Wilson said Kaihau was "very very lucky".

He arrived to see a half moon-shaped wooden post about 15cm wide and 5cm thick jutting from the shattered windscreen.

The post had gone about 1m into Kaihau's shoulder but firefighters trimmed it so he could be taken to hospital.

Wilson said the process was complicated because there were nails in the wood. "He was an excellent patient, he never made a noise. He could talk but he never moaned."

Wilson said it was "unbelievable" that Kaihau could swing his legs and get out of the car - but the problems didn't end there.

"We couldn't put him lying on a stretcher. We had to sit him up and reverse him into the helicopter because of the way the piece of wood was sticking out of him," he said.

"It smashed his collarbone. It just couldn't have gone anywhere else and come out the other side. It missed his heart by a whisker. The end looked like a broken-off piece and the pointed end must have made it go through him so quick."

Kaihau said he was in pain all the way to hospital, where he had 5 1/2 hours' surgery.

Surgeon Adam Dalgleish said he was amazed his patient did not lose his arm and suffered no damage to nerves and major arteries in his neck.

"I examined him before the surgery and was amazed that he could move his hand and had normal sensitivity and could feel tingling," he said.

After an operation to remove "foreign material" from his shoulder, Kaihau had plastic surgery to fix his broken bones and seal the wound.

He suffered a dislocated shoulder joint and a fractured shoulder blade.

"The whole shoulder was detached from the chest," said Dalgleish. "We needed to stabilise it back to his chest. He's not out of the woods yet - he will need more surgery to stabilise it long-term," he said.

Kaihau spent about five days in bed but began walking and physiotherapy on Tuesday. He was discharged on Thursday - the day after his family burned the wood because it was tapu (forbidden).

"My uncle wanted to carve it but I thought it was bad and wanted them to get rid of it," Kaihau said.