Calcium Hydroxylapatite With Integral Lidocaine Provides Improved Pain Control for the Correction of Nasolabial Folds

August 2016 | Volume 15 | Issue 8 | Original Article | 1005 | Copyright © August 2016


Daniel Schachter MD FRCPC,a Vince Bertucci MD FRCPC,b and Nowell Solish MD FRCPCc

aPrivate Practice, Toronto, ON, Canada
bUniversity of Toronto, Toronto, ON, Canada; Private Practice, Woodbridge, ON, Canada
cUniversity of Toronto, Toronto, ON, Canada; Private Practice, Toronto, ON, Canada

Abstract
Calcium hydroxylapatite microspheres in a carrier gel (CaHA; Radiesse®: Merz North America, Inc., Raleigh, NC) is approved by the United States Food and Drug Administration for subdermal implantation for the correction of moderate-to-severe facial wrinkles and folds, such as nasolabial folds (NLFs). Lidocaine is often mixed with injectable dermal fillers to reduce injection pain. A new formulation of CaHA has been developed with the convenience of integral 0.3% lidocaine, CaHA (+).
This multicenter, split-face, double-blind study randomized subjects to receive treatment with CaHA (+) in one NLF and CaHA without lidocaine in the contralateral NLF. The pain level for each NLF was evaluated immediately following the injection using a 10-cm visual analog scale (VAS), and every 15 minutes for 60 minutes plus follow-up visits. Additional endpoints included aesthetic outcomes and subject preference. All subjects (N=102) received treatment.
CaHA (+) treatment resulted in a statistically and clinically significant reduction in pain ratings immediately after injection compared with CaHA. The mean difference in VAS scores for pain was -4.41 (P<0.0001). In 90% of subjects, the VAS scores were ≥2.0 cm lower for the CaHA (+)-treated NLF. A significant reduction in pain ratings throughout the first hour after injection was observed with CaHA (+) compared with CaHA (P<0.0001). Both treatment groups achieved significant aesthetic improvement; however, the pain differential resulted in a subject-reported preference for CaHA (+). CaHA (+) with integral lidocaine significantly reduces pain and is as effective as CaHA.

J Drugs Dermatol. 2016;15(8):1005-1010.

INTRODUCTION

Calcium hydroxylapatite microspheres in a carrier gel (CaHA; Radiesse®: Merz North America, Inc., Raleigh, NC) is approved by the United States Food and Drug Administration (FDA) for subdermal implantation for the correction of moderate to severe facial wrinkles and folds, such as nasolabial folds (NLFs). CaHA provides immediate volume correction and induces collagenesis at the injection site to provide long-lasting treatment results (≥ 1 year) in many patients.1-4 Lidocaine is often combined with injectable dermal fillers to reduce injection-site pain. CaHA mixed with lidocaine has been shown to decrease injection-related pain, and was preferred by patients over control injections with CaHA alone.5
In 2009, the FDA approved a method for mixing CaHA with lidocaine at a concentration of 0.3%; in January 2015, the FDA approved a new formulation of CaHA with the convenience of integral 0.3% lidocaine hydrochloride (CaHA (+); Radiesse® (+); Merz North America, Inc., Raleigh, NC) for the correction of moderate-to-severe facial wrinkles and folds, such as NLFs.6 Whereas a previous in vitro study found that mixing lidocaine somewhat reduced viscosity and elasticity,7 a more recent study has found that CaHA with or without integral lidocaine had similar extrusion forces and rheological profiles, overall CaHA and CaHA (+) demonstrate the highest complex viscosity (η)* and elastic modulus (G’) compared with other hyaluronic acid (HA) fillers.8
Our study assessed pain control and safety of CaHA (+) with integral lidocaine in comparison to CaHA without lidocaine for the correction of NLFs.

METHODS

This was a multicenter, randomized, split-face, double-blind study conducted over 4 weeks. A total of 102 subjects from 3 study sites in Canada were randomized to receive treatment with CaHA without lidocaine in one NLF (control) and CaHA (+) with lidocaine in the contralateral NLF (treatment) during a single treatment session. The order of treatment and the treatment side were randomized, and both subjects and investigators were blinded to the randomization assignment.
Each NLF was injected using a 27-gauge inner-diameter needle into the subdermal plane; either 3/4 inch or 1/2 inch needles could be used at the discretion of the injector. The method of injection was linear threading, which is defined as the retrograde depositing of the dermal filler in a single strand. The volume of
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