It’s all semantics, what a clinic may like to call something to either impress or reduce the impact of the subject.
A top up is akin to having a drink, drunk some of it, and someone asking how you are. You turn and say I could have a top up. Even though you have a drink left. Or, more ironically having drunk it all saying I could do with a top up. So, under that scenario a top up could be a sip gone and replenished to it all gone and a new order made.
I prefer the use of the phrase a touch up. As that is what a few grafts would be, a touch up. If a painter missing a second coat in a small corner, it’s a touch up. If they miss an entire wall or 50% it needs to be repaired/redone.
In hair transplant terms I would say the use of the phrase top up is sometimes used to minimise the sound of the issue. As there is no definitive number to the phrase. It implies though it is a small number, an inconsequential number and event. Nothing to make an issue of. A top up though is not used in my opinion to infer every one has a second procedure at some point in time. That is a second procedure, planned for due to progressive hair loss or a hair loss pattern that could be treated in one procedure. It’s not a top up of the first, it is a second procedure. It should not be referred to as a top up as it gives a very different reference to why it is being performed. Many have second procedures to treat a wider hair loss zone. Few have top ups to treat the pre existing area already treated. I’ve had hair transplant top ups after I went through bad surgeries. It´s not a phrase I would suggest tells the story for almost all situations. If a number had to be applied, I would say 10% of the surgery size would be fair. That then keeps in line with the use of the phrase and the minimal work.
A repair does not have to mean scar repairs, dealing with pitting, plugs or ridging. It can simply mean repairing a previous surgery that did not perform the level of growth expected. Poor growth or yield may not look unsightly or course any significant problem. Withstanding the loss of hair from the finite donor. But a repair of the previous transplant is required to make good the look, technically what was expected and therefore meet the expectations of the individual. This can simply be adding more hair. But, it is a repair, more hair is needed than expected to achieve the initial result. The donor is further depleted, which was not expected. Hopefully not to the point it makes a significant difference to future hair restoration.
If there was an underlying condition such as LPP that was not evident prior to surgery, then these cases are categorised differently.