AUGUSTIN BETZ Born 1950 (age 69) Source: https://www.betzinstitute.com/en/about-us.html#augustin-betz

JEAN MARC GUICHET: Born 1961 (age 58) Source: http://leg-limb-stature-lengthening-taller-height-increase-cosmetic.eu/encyclopedie/index-esp.php?page=autor

DROR PALEY: Born 1956 (age 63) Source: https://en.wikipedia.org/wiki/Dror_Paley

ROBERT ROZBRUCH: Born 1965 (age 54) Source: http://www.limblengthening.com/wp-content/uploads/2017/05/SR_Rozbruch_CV4.19.17.docx.pdf

CRAIG ROBBINS: Estimate: 52  (estimated from year of education) Source: http://www.limblengtheningdoc.org/files/Craig_Robbins_CV_6_13_14.pdf

KEVIN DEBIPARSHAD: Age 37 Source: https://www.healthgrades.com/physician/dr-kevin-debiparshad-y9pdhsz

MANGAL PARIHAR: Estimate: 57 (estimated from year of education) Source: http://mangal.tripod.com/resume.html

FRANZ BIRKHOLTZ Estimate: 44 (estimated from year of education) Source: http://www.walkamile.co.za/dr-franz-f-birkholtz-and-phillip-de-lange.php

GUIDO KOHNE Born 1972 (age 47) Source: https://www.gesellschaft-fuer-fusschirurgie.de/ueber-uns/vorstand/dr-med-guido-koehne.html

DIMITRIOS GIOTIKAS Estimate: 43 (estimated from year of education) Source: https://uk.linkedin.com/in/dimitrios-giotikas-md-phd-32353774

LEONID SOLOMIN Born 1963 (age 56) Source: http://ortho-suv.org/index.php?option=com_content&view=article&id=110&Itemid=74&lang=en

AMAR SARIN: Estimate: 55 (estimated from year of education) Source: https://www.drsarin.in/profile.html

Unknown:

SHADAB MAHBOUBIAN
DONGHOON LEE
ALEX MONEGAL

Age may not reflect a surgeon's ability or skills. In some cases it may not fully reflect years of experience also because of varied career paths. Overall someone extremely old may not fully healthy and someone extremely young may not have had enough experience. Anyway this was just for curiosity.