Pre and Postop Questionnaire

I have around 10 sets of people who have completed a questionnaire before and after intervention

For 29 or so people I they have only returned either one of pre or post op scores.

For analysis sake I know I can do something like a paired-test to compare before and after questionnaire scores for the completed set of 10

However, am I able to include the other 29 in the analysis or is there no point reporting back on that?