Pruning sprouts is similar to pruning branches in the sense that both have swollen areas at the base that should not be wounded. Leaving stubs beyond the swollen area is undesired for sprouts or branches. Branches have branch collars and sprouts also have a swollen area at the base, however it is not a branch collar. The swollen areas of both sprouts and branches are made up of tissues that contain trunk or parent stem tissues. Correct pruning of sprouts on an apple tree (below).
On the left. You can see the tan area where the outer bark (phellem) has been shed. You can see the very small section of green /brown (black arrow) that remains after I pruned. The target is as close to the tan as possible without wounding the trunk (tan) and without leaving a stub. My pruning cut was as close to correct as I could get.
For me, and not the last word, the pruning of sprouts on apple trees is very common. I find it hard to understand how you could use a chain saw to prune such sprouts, on an apple tree, and not wound the parent stem.
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When topping cuts are made on large branches and sprouts form, they are
epicormic (upon the trunk) and not attached as branches are. They form on the outer edge of
the stem and are weakly attached verses branches which have branch collars.
Picture below.
This picture is a hollow top from a topping cut. The picture is from Italy. You can see that as the sprouts grow bigger and bigger and grow to be a high risk of hazard for failure. These type of treatments need to stop.