Sorry you’re having this difficulty. You’re not the only one to have reported this – we hear about it sometimes from a chemo experience too. When the imagery is used at such a critical, vulnerable time, the negative associations can become very embedded and intense.
You might want to try to use some of mine with different music in the background – that might be enough of a change to avoid kicking loose the associations with that old surgery. The PTS imagery, for instance, uses very different music, as does the Panic Attack imagery (different from either). And Steve Kohn has also scored the imagery for sleep using different music from either of those; and there’s completely different scoring for the imagery to help with weight loss and smoking cessation.
If a change in the music doesn’t do it, and the association of my voice with that earlier trauma is too strong, you might want to try a different narrator altogether – there are some very powerful, calming, effective audio programs by many gifted practitioners, so you don’t have to feel you’re stuck with me – perhaps if you tell me which chronic health issues you’re looking for help with, I can advise you accordingly.