a professional photographer. Then, the red nail polish and the measuring tape described earlier were used (Figure 2AB).
In the second live procedure, PM observed colleagues’ injection during 2 workshops (Figure 3ABC) took close-up photographs, with the colleagues’ oral consent. In the one-to-one workshop, the red nail polish and measuring tape were used (Figure 3AB). Only close up photographs were taken (Figure 3C).
Depths of Injection in the Dermis
Superficial reticular dermis injections
In one investigator’s private practice setting (PM), NLF of 2 patients were injected by the same injector, with a superficial technique called the “blanching technique.â€16 The needle penetrating angles were measured, the inserted needle section was measured, and the depth of injection (sin (angle) x inserted needle length = depth of penetration) was calculated. Investigators determined that, using the blanching technique, injection into the superficial reticular dermis could be achieved.
Results of the determinations in the live injections in the private practice setting are shown in Table 2 (part 1).
Two other live injection activities focused on determination of depth of injection. In the first activity, a one-on-one workshop between 2 of the authors (PM, MSD), 3 subjects were injected in the nasolabial folds, using a BD® 30G half-inch needle. The injector (MSD) typically inserted her needle into what she perceived to be the superficial reticular dermis. Two of the 3 patients were injected on one side in the “superficial†reticular dermis of the NLF. For those 2 subjects, the other side was injected in the “mid†reticular dermis. The 3rd patient was injected only in the “mid†reticular dermis, but with 2 different penetration angles.
Angle of implantation, length of needle inserted, and depth of injection were all reported. Angle of implantation was
determined with the protractor; length of needle part was determined by use of the red nail polish described earlier; and depth of injection was determined by use of the mathematical formula also shown earlier in the paper. With an angle greater than 10° and/or a penetration needle length too long, even the experienced injector appears to be in the deep dermis, not in the superficial reticular dermis.
Results are shown in Table 2 (part 2).
In the second activity, 3 physicians from a group of 12 were randomly selected to attempt to inject precisely into the superficial reticular dermis of 4 patient volunteers (Figure 3C). Measurements showed that, even when colleagues know that they are being closely observed, they are unable to inject in the superficial reticular dermis. Results are shown in Table 2, part 3.
