Neurologists/neuro-surgeons

In the USA or Canada:

http://www.cavalierhealth.org/neurologists.htm

In the USA and International:

http://vetspecialists.com/

Or: http://find.vetspecialists.com/

In the UK:

http://www.vetindex.co.uk/vetindex/neuro_ref.htm

Orthopedic specialists/surgeons

In the USA:

https://online.acvs.org/acvsssa/rflssareferral.query_page?P_VENDOR_TY=VETS

In the UK:

http://findavet.rcvs.org.uk/find-a-vet/advanced-search/

Holistic vets (acupuncture, herbs, homeopathy, etc):

In the USA and International:

http://www.ahvma.org/find-a-holistic-veterinarian/http://www.ahvma.org/find-a-holistic-veterinarian/

American Academy of Veterinary Acupuncture: https://www.aava.org/

Chi Institute and China National Society of TCVM Certified Veterinary Acupuncturist (CVA):

http://www.tcvm.com/Resources/FindaTCVMPractitioner.aspx

Association of British Veterinary Acupuncturists:

http://www.abva.co.uk/find-a-vet/

Physical Therapists

In the USA and International:

http://www.caninerehabinstitute.com/Find_A_Therapist.html

*Some specialists require a referral from a general vet. Universities and teaching hospitals in your area might also have specialists available, please check with them too.