I've actually spoken to a few patients with upper lip paresthesia actually. My sample size isn't huge but it seems to be correlated by surgeon so I think it comes down to technique. Numbers are all over the board for nerve sensation recovery. The most cited number I see is 10% will have permanent nerve loss. From my interviews, I'd put that number much higher, between 50% - 90% depending on how you define "not fully recovered" and the type of procedure done (my sample is biased by the riskier procedures). 2% sounds like about the right number for those who are bothered by it but there's nearly always some amount of loss. And it's not just jaw surgery, all surgery is associated with some amount of paresthesia but I'd rather lose it on, say, a calf then on my lips. Some say it's a function of age, others say age just affects recovery time. A few facts are clear to me, regardless of technique: IAN is going to be stretched in a BSSO, IAN will stretch again in SG, nerves feeding maxilla are going to be cut in a LeFort, and nerves are more likely to devitalize in segmental LeForts. Even if the nerves themselves fully recover, sensation will be altered and the brain has to relearn how to feel. There are exercises that can be performed during this process to increase the chances that your brain adapts well but, strangely, none of the surgeons I've met seem to know or care about it.
