Mid Dermis Injections
Live treatments in the “one to one†workshop training session, the injector (MSD) was asked to inject in the mid reticular dermis as she typically would in her clinical practice.
The length of needle penetration was determined in the similar manner as it was for the superficial dermis injection session, ie, with the red nail polish applied to the needle after the needle had been inserted. The angle of penetration was also determined as it has been previously, ie, with the protractor to measure the angle on the photograph. Investigators determined that, even when the experienced injectors used the conventional angles and a non-retrograde injection technique, the gel was injected too deeply, into the hypodermis (subcutis).
Results of their findings are shown in Table 3.
Ultrasound and biopsy findings in the buttock
In an unpublished and still ongoing mid-reticular dermis ultrasound study,13 11 subjects agreed to have needles and HA gels implanted into the buttocks area. Using the mathematical formula provided earlier, investigators determined that injection would be at a depth of ~ 1.1 mm to 1.5 mm. Depths required varied. Using Della Volpe’s data, injection in the buttocks had to be between 1.07 mm and 2.0 mm. As a part of the ongoing unpublished study, investigators also calculated that depth in the mid dermis of the buttock for one patient (GM-5) had to be 1.25 mm to 2.25 mm and had to be 1.06 mm to 1.77 mm in the buttock for another patient (CP-6). For the third patient (IT), we had no prior histological data about depth because we had not performed biopsies. Measurements taken from the data-gathering show that investigators were indeed in the mid reticular dermis with these 3 subjects. Data are shown in Table 4.
Ultrasound only findings in the NLF.
In the NLF-injected patients, only ultrasound measurements are available; facial biopsies were not performed. Using Della Volpe’s data, we determined that our needles were to be placed from 1.01 mm to 1.86 mm in order to be in the mid reticular dermis of the nasolabial area. Investigators concluded that placement was indeed in the mid reticular dermis, even though the skin of the subjects was thinner than that presented by Della Volpe. Measurements from 2 subjects are reported in Table 5.
