The PNB classification for treatment of fingertip injuries: the boundary between conservative treatment and surgical treatment.

The PNB classification, which was advocated by Evans and Bernadis, separates the injuries into their effects on 3 components of the fingertip: pulp, nail, and bone. Because each component is subdivided into 7 or 8 items, this can describe fingertip injuries more precisely. Between 1997 and 2003, we treated 381 fingertip injuries (279 males, 102 females; average age, 41.2 years) in our facilities. A 3-digit number was provided for each of the 381 cases in accordance with the PNB classification. We extracted patients in whom amputated tissues did not exist, and predicted the boundary between conservative treatment and surgical treatment by individually comparing the curative results of the same type of injuries. In conclusion, PNB 355-366 and PNB 455-466 were most suitable for surgical treatment, and the boundaries between surgical treatment and conservative treatment were PNB 386 and 666 and 700. The results, which are the criteria for surgical treatment, are summarized as follows; 1) More than two thirds of the distal phalanx remains. 2)The nail bed defect ranges from one third to half. If the defect is more or less than the criteria, the surgical treatment is less significant. Recognition of the boundary and prevention from unnecessary surgical treatment leads to minimum invasive surgery for fingertip injuries.