can hair transplant be done on a scar produced by a craniotomy surgery on head?

Hair transplants and Scalp Micropigmentation (or both) can be used to treat craniotomy scar.Hair transplant will just add hairs but you may need more than one surgery as transplanted hair may not completely cover the scar.Neograft, ARTAS, and FUE has nothing to do with results. They are just methods (instruments)  in harvesting the grafts.  Don't be fooled by technology.Scalp MicroPigmentation can help disguise the scar by decreasing the contrast between hair and scalp.A combination of SMP and hair transplant may provide optimal results.

Yes, most scars on the scalp are amenable to hair transplantation.  In fact, a good part of my practice is putting hairs into scars from prior strip method procedures from hair transplantation. However, some scars won't accept a graft.  Thus the combination is to punch out to shrink areas that aren't good for grafting, and to put hairs where you can.  You will need to see someone with experience to get an optimal result.  I recommend a Board Certified plastic surgeon who understands "tissues" and NeoGraft technology for transplantation.  Very good question.

For your best answer, you should consider a face to face consultation with a surgeon that is familiar not only with hair restoration procedures like Neograft/FUE but also scar revision procedures.  It is impossible to say if you would be better served by having the scar cut out and revised in hopes of improving or disguising it or if there is enough good circulation in the scar to support the growth of transplanted follicles.  Rather than guess or assume, a consultation is your best bet.  Good luck