To compare swelling, pain and bruising after injection of a dermal filler with a blunt micro cannula versus a traditional sharp needle
A prospective study was designed and performed on 11 patients with no previous history of filler injection. A 1.5cc syringe of calcium hydroxyapatite based filler was injected to the right and left Nasal Labial Fold (NLF). Random selection of right and left sides was determined with a coin toss and only the injector was aware of which technique- traditional needle or blunt microcannula was utilized for filler placement.
All eligible patients signed an informed consent and photo release form to participate in the study. Photos were taken prior to injection, 15 minutes post-injection and also at post procedure day 1, 5, 7, and 14.
Topical anesthetic cream was applied and left on for 10 minutes on each NLF prior to injection. Each syringe was mixed with .26cc of 1% Lidocaine. The distal part of the NLF on both sides was iced and then a 22 gauge needle was used to create an access point on both sides in order to maintain consistency. A 27 gauge 1.5 inch cannula and a 27 gauge 1.5 inch hypodermic needle was then used to place the filler material in a retrograde, linear, threading fashion.
Following the treatment, swelling, pain and bruising were assessed at the following time points: 10 minutes post-injection, day 1, day 5, day 7 and day 14. The patient and a blinded observer at each time point completed a questionnaire assessing the parameters and assigning a numerical score.
Every patient complied with all requirements, and no patient dropped out of the study. The data was tabulated and then analyzed.
On the day of injection, no subject reported any bruising to either side (0 out of 10). The average pain scale on the side that was injected with the cannula was a 2 out of 10 and the side that the needle was used averaged 3 out of 10. Swelling was more severe in 7 out of 11 patients on the needle side.
On post-injection day 1, 4 out of the 11 subjects reported more swelling on the side the cannula was used and 7 out of 11 subjects reported more swelling on the side that the needle was used. On day 1, only 5 out of 11 subjects bruised. 4 of them bruised on the side that was injected with the needle, and 1 on the side with the microcannula. Pain was 1 out of 10 on both sides.
By day 5, only 3 subjects reported bruising and they were all on the side that the needle was used. Swelling was reported to 4 out 11 injected with the needle and 1 out of 11 on the microcannula side. Pain was 1 out of 10 on both sides.
On day 7, there were no reports of bruising (0 out of 11) and only 2 reports of swelling, again on the side that was injected with the needle. 1 patient reported more swelling on the cannula side. Pain was 0 out of 10 on both sides.
By day 14, there were no reports of pain, bruising, or swelling to either side injected. Subjects reported to favor the results on the side that the cannula was used from day 1 thru day 14. By day 14 both sides injected were favorable to the subjects.
The blinded observer reported that there was more bruising (4 out 0f 11) to the side that was injected with the needle on day 1, 5, and 7. Swelling was noted to be more severe (7 out of 11) immediately, day 1, 5, and 7 on the needle side. They also reported that 8 out of 11 subjects had a more favorable result on the side that was injected with the cannula from initial injection day but by day 14, both sides were favorable, with no discernible difference.
Blunt microcannula use in this study initially showed more rapid patient recovery, but by day 14 there was no discernible difference in swelling, pain and bruising.
Patients are interested in minimal down time after injectable filler procedures. This can be better accomplished with blunt microcannula usage as opposed to traditional methods using sharp needles.
The use of blunt microcannulas reduces the risks of intravenous and/or arterial embolisms, enhancing patient safety.
By decreasing risks associated with filler injections as well as providing a more comfortable patient experience, we feel that the microcannula should be strongly considered as an option in this setting. A cost analysis assessment and further evaluation with a greater number of patients in the future is warranted.