Can head shape alter in facelift surgery?

It is highly unlikely that facelift surgery would alter one’s head shape.  Most likely the subtle surgical changes in the patient’s skin and soft tissue, such as removing and tightening the excess skin or filling the sunken areas, is giving you an impression of a head shape change.  As long as you consult with a board certified plastic surgeon with expertise in facial rejuvenation, there will be no change in head shape or size.

It's possible to change the physiologic proportions of the facial tissues using augmentation or reduction techniques, but in most cases, it's not necessary.  This is a very individual decision.  The skull and bones themselves are not changed with facelifting surgery.  Be sure to discuss your goals and concerns with your board certified plastic surgeon and consider the pros and the cons. Be certain your surgeon is properly certified.  I've attached a link where you can start your search. 

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So much of this answer would depend upon what you mean by "changed shape "we would need to see the pictures you are referencing to really understand this.  However, a well-executed facelift will often slightly change the shape of once face from a more boxy, bottom heavy face, to the more youthful, attractive, heart-shaped face.Best of luck!

Dr. SubbioBoard-Certified Plastic SurgeonNewtown Square/Philadelphia, PA