[7] In 1961, Themen went to complete his studies at St Mary's Hospital Medical School, Paddington, where he qualified in 1964; specialising in orthopaedic medicine, he eventually became a consultant.

[7] Themen has said: "I had pretty much decided that I could continue to practise medicine and play saxophone, and Alexis, being heavily into blues as well as taking in jazz influences like Charles Mingus, furthered my knowledge of music quite a lot.

Themen has also played and toured with visiting US musicians, including Charlie Rouse, Nat Adderley, Red Rodney, George Coleman, and Al Haig.

[5][7] He was featured in a profile on composer Graham Collier in the 1985 Channel 4 documentary Hoarded Dreams [9] In 1995, Themen formed a quartet with pianist John Critchinson.

Themen recalled that his musical career had begun with the clarinet which, due to a missing page in the instruction manual, he had originally played with the mouthpiece upside-down.