Estimate the rotation of central axis of a 3D curve

I have N points in [x,y,z] and this kind of takes a spiral shape. Is it possible to find the central axis of such a spiral. This is not a regular helix.

My aim is to find the maximum distance of the curve from the central axis. I was trying to solve this by finding the central axis and from this estimate the rotation of this axis from the Z axis. Then rotate the 3D curve to have its central axis as the Z axis, from here I can find project and find the maximum radius from the center.

If there is any other easy way, please let me know.

Thank you.

[Image Analyst]

My first guess would be to use Principle Components Analysis. I'd think one of the PCs should run down the main axis and the two others would be perpendicular to that. Do you have data you can supply?

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Yes, I am attaching the mat file here. Its size is [Nx3] where the columns correspond to x, y and z positions of the 3D curve.