Swelling

Figure 5

In all, 65% of patients reported no visible swelling, while 35% of patients reported mild to moderate swelling (Figure 5). No patients reported severe swelling, which again indicates that swelling following microcannula treatment will be unlikely to affect social events.

Tenderness at insertion site

A total of 58% of patients reported no pain or discomfort at the microcannula entry point owing to the lidocaine/adrenaline bolus injection (Figure 6) and 30% reported a pain rating between 1 and 3. Only 12% of patients rated the pain at the entry point post procedure between 4 and 10. This indicates that for the majority of patients (88%), very little to no pain will be experienced when injecting the local anaesthetic at the entry point. However, it also indicates the variability of pain tolerance (or perceived discomfort) for a fairly large number of the general population (12%).

Tenderness of the treated area(s)

This analysis specifically looked at the degree of pain or discomfort that patients experienced at the treated area(s) during the microcannula procedure. In all, 62% of patients felt no pain or discomfort during the procedure and 21% of patients reported a discomfort level that ranged between 1 and 3 (Figure 7). Fifteen percent of patients rated the discomfort level between 4 and 6. This indicates that for a majority of patients (85%), the use of the microcannula is a comfortable procedure. The degree of pain that the patient experiences would be dependent on two main factors. The first is the technique used during cannula treatment, as the more aggressive the injector is the greater the degree of discomfort that will be felt. Figure 6Additionally, if the cannula does not glide easily through the fatty layer, the more pain or discomfort a patient will experience, and forcing the cannula in the wrong plane of tissue will also increase patient discomfort. The second factor is the type of filler used, as fillers with no lidocaine tend to burn as the material is deposited and will increase the discomfort level of patients. All patients enrolled in the study were treated with either the Juvéderm® ULTRA® range or Juvéderm VOLUMA® (Allergan, Irvine, CA), which contains lidocaine.

Patient satisfaction

Figure 7

All patients were asked whether the filler treatment met their expectations, and 98% of patients reported ‘yes’ (Figure 8). All patients were then asked to rate the degree of satisfaction starting at 0% and ending at 100%; 63% of patients were between 90% and 100% satisfied; 87% of patients were between 80% and 100% satisfied; and 93% of patients were between 70% and 100% satisfied with their end result (Figure 9).
The author also asked in the online questionnaire, ‘Did the use of the microcannula change your view on future filler treatments?’ and ‘Would you recommend this treatment to your friends?’

In all, 97% of patients responded that the use of the microcannula had changed their view on future filler treatments, and that 95% of treated patients would recommend the microcannula to their friends (Figure 10).

Discussion

Figure 8

A literature review surprisingly reveals very few medical studies that examine the side-effect profile of microcannula versus hypodermic needle. The study objective of Fulton et al1 was to compare the injection of dermal fillers with microcannulae versus hypodermic needles with regard to ease of use, amount of filler required to achieve desired aesthetic outcome, perceived pain by patient, adverse events such as bleeding and bruising, and to demonstrate the advantages of single-port injection technique with the blunt-tip microcannula. Ninety-five patients aged 30–76 years with a desire to augment facial, décolleté, and hand features were enrolled in the study. Anaesthesia was used with a topical anaesthesia peel‑off mask of lidocaine/tetracaine. The volume of hyaluronic acid injected was variable, depending on the depth and the extent of the defect. There were no significant differences in the Global Aesthetic Improvement Scale (GAIS) score between the microcannula and the hypodermic needle.

Figure 9

The Visual Analog Scale for pain assessment produced a different picture; pain was described as 3 (mild) for injections with the microcannula and this increased to 6 (moderate) for injections with the hypodermic needle. Mild erythema was observed by the authors of this study following use of the microcannula. Unfortunately, the authors did not quantify the degree or extent of bruising and ecchymosis (for both microcannula and hypodermic needle), except to state that bruising was more marked following the use of the hypodermic needle.

Needle versus cannula

Figure 10

Teresa A. Cattin’s publication, ‘A single injection technique for midface rejuvenation’2, describes the approach and technique used for microcannula enhancement of the midface, specifically the cheek and nasolabial fold. A total of 60 patients were treated over an 18-month period and no significant adverse effects were reported. Complications were limited to a small needle mark at the entry point, which resolved spontaneously. Cheek redness was also reported, but tended to subside within 15–20 minutes of treatment completion. Slight swelling at the entry point on the zygomatic arch was also noted by the author. Further observations include an observed reduction in bruising and swelling when compared with multiple deeper injections.

Similarly, Niamtu’s publication, ‘Filler injection with micro-cannula instead of needles’3, explains the blunt cannula’s main advantage is an atraumatic procedure with less oedema and bruising. No comparison is made in the publication of the potential side-effects and their degree, or quantifying their extent when comparing hypodermic needles to cannulae.

Conclusion

Following from the above analysis of the literature review and the study results, one can state that on the whole, visible side-effects can be described as ranging between minor to moderate and can be easily hidden with make-up. Furthermore, using a microcannula is a fairly comfortable experience for the majority of treated patients and patient satisfaction of the end results remains high.

The author believes this is a very interesting study as the results not only quantify the degree and extent of potential side-effects, but also reveals a patient’s perspective on the side-effect profile of dermal filler treatments in multiple anatomical areas using microcannulae. Typically, when side-effects are assessed by physicians, we base our opinions on the degree and extent of complications we have encountered in our clinical practice. What we, as physicians, think is a minor side-effect (e.g. bruising, erythema, or swelling) may in the patient’s mind be severe or socially unacceptable. This study gives us a clearer picture of how our patients may view side-effects when we perform dermal filler treatments with a microcannula.