TORONTO -- Spencer West may have left the top of Africa's tallest mountain several days ago now, but he's clearly still on a high -- and a mission -- following his epic week-long trek that captured international attention.

Speaking from the airport in Nairobi, West said he still can't quite get his head around the fact that he scaled Kilimanjaro, mostly by walking on his hands.

"I still haven't 100 per cent processed what happened," West told The Canadian Press. "(But) I've finally started to get some of the dirt out of my fingernails."

West, 31, an American citizen who has lived in Toronto for the past four years, had his legs amputated just below the pelvis when he was five because of a genetic defect. Doctors gave a grim prognosis about how he would fare in life.

Now, his story is both motivational and inspirational.

"If I can climb the largest mountain in Africa when I was told I would never walk or be a functioning member of society, then what more can individuals do in their daily lives to start 'redefining possible'," West asked.

The 2-foot-7 West initially gave little thought to an off-hand suggestion from Canadian child-rights activist Craig Kielburger several years ago that he try to scale the mountain in Tanzania.

However, during a visit to Kenya in 2008, a little girl remarked that she didn't know white people could lose their legs.

"That one phrase changed the entire course of my life and helped me recognize how I could use my story to inspire people to overcome obstacles," West said.

When a severe drought hit the region, West decided to try to help. Together with best friends David Johnson and Alex Meers, they came up with the "Redefine Possible" campaign, with the goal of raising $750,000 for a sustainable water project for 18,000 Kenyans.

The trio spent a year preparing to make the trek that about 60 per cent of those who try fail to accomplish.

He had expected to hand-walk about half the time and use his wheelchair the other half, but the rugged terrain forced him to use his blistered hands about 80 per cent of the ascent.

"That started to take a toll on my wrists, and my elbows, and my shoulders," he said.

In a few spots, porters strapped him to their backs and carried him, all the while a documentary crew in tow.

The bleakest moments came on a freezing, windy summit day, when Johnson and Meers were hit with severe altitude sickness.

"I thought I don't know if this is actually going to happen," West said. "It was the first time I actually wished I had legs."

Ultimately, the trio persevered, one agonizing step at a time, finally collapsing under the sign heralding the 5,895-metre summit last Tuesday, seven days after they started.

They took in the vista: glaciers on one side, a sea of clouds on the other, and the long drift of snow they had just traversed.

"It was beautifully overwhelming," West said.

"We hugged and cried a little bit and enjoyed the moment."

Among the myriad thoughts that went through his mind was one that he had achieved something "for anybody who has ever felt like an outcast."

With the two-day descent now behind him, the pain in his aching shoulders has started to ease and the calluses on his hands are beginning to fade.

But West said he still wants to try to reach his $750,000 fund-raising goal and, most of all, he wants the world to know that redefining the possible is possible.

Donations can be made through the website of the group Free the Children.