The lips are an important aesthetic landmark on the face. Thick and voluminous lips represent beauty and youth in women, and various cosmetic procedures have been performed to achieve this look. Since the 1980s, surgical methods such as the upper lip lift, Austin-type lip lift, and subnasal lip lift have been introduced [1-3]. In 2019, Hwang et al. [4] determined the length of the upper and lower lips and philtrum that provided the attractive and healthy-looking appearance most preferred by Koreans. They defined attractive and healthy-looking lips using four lip-related ratios, and these results have been applied to aesthetic lip plastic surgery in Koreans.

With the central lip lift, patients can achieve changes in upper vermilion thickness and lip height. Additional cosmetic procedures such as botulinum toxin injection, filler injection, or fat grafting can also improve surgical outcomes [5-7]. In a previous study, Lee et al. [8] confirmed that the height of the upper lip increased significantly as the philtrum length was shortened in central lip lift procedures. Based on the research of Hwang et al. [4] this study investigated whether attractive lip ratios could be obtained in Koreans by performing central lip lifts without additional cosmetic procedures. In addition, the change in the position of the philtrum with the central lip lift affects the columellar-labial angle (CLA). Therefore, we also investigated the aesthetic effects of this unintended CLA change.

Of 102 patients, 87 satisfied the inclusion criteria. There were 10 men and 77 women with a mean age of 35.6 years (range, 19–67 years). The mean follow-up was 24.2 months (range, 6.0–31.2 months). The preoperative and postoperative patient distributions are presented in Table 2. The preoperative mean was 0.34 for LTW, 0.76 for ULR, 0.30 for VUL, and 101.59° for CLA. After surgery, the mean respectively changed to 0.39 for LTW, 0.84 for ULR, 0.39 for VUL, and 95.04° for CLA. The changes in all lip-related ratios before and after surgery were statistically significant when compared using the paired t-test (Table 3). Furthermore, all lip-related ratios were close to the attractive values identified by Hwang et al. [4].

“Pouting” lips are considered symbols of beauty and youth. The lips undergo morphological and histological changes with age, including elongation of the upper lip height, a decrease in the visible vermilion, thinning of the epidermis and dermis, and atrophy of the orbicularis oris muscle. These changes result in a total volume loss of the lips [9,10].

In recent years, various upper lip augmentation and lip lift techniques have been introduced to overcome the effects of aging and make the lips more attractive. Permanent injectable fillers and lip implants can achieve great effects through simple procedures, but there are possible side effects, such as infection, foreign body granuloma, and allergic reaction [11,12]. Free fat grafting has been a widely used and effective method without such side effects, but further studies are needed to assess whether it can be maintained long-term [7,13,14]. A mucosal advancement technique increases the vermilion height with the scar hidden but has the potential for numbness around the lips [15]. Since Rozner and Isaacs [16] first performed the lip lift in 1981, several techniques such as the Austin-type, scarless upper lip suspension, and subnasal lip lift have been developed [1-3,17]. The authors’ central lip lift successfully increased the height of the visible upper vermilion while reducing the philtrum length (Fig. 3) [8]. Austin and Weston [2] reported that raising the central part of the upper lip may cause the patient to look sad by making the edge of the lips turn down. This phenomenon is called the “sad appearance deformity.” To prevent this, we extended the incision line to the lateral aspect of the alar so that the lateral aspect of the lips was slightly elevated. The upper vermilion was everted upward by removing the skin and muscle right below the columellar-labial junction in the central lip lift. As the lip everts, the incisor edges of the upper teeth may be exposed.

Several studies have been published on ideal lip proportions. Penna et al. [9] showed that the attractive ratio of the height of the upper vermilion to the length between the lips and nose was 0.28 for males and 0.28 for females. However, Asians tend to have a smaller oral width and retruded chin than Caucasians and the lips of Asians are more prominent [18]. Therefore, healthy-looking and attractive lips may differ according to race. Hwang et al. [4] surveyed 258 Korean women and 72 Korean men to rate four lip ratios for attractive, healthy-looking lips. The preferred lip ratios were LTW, 0.4; ULR, 0.8; and VUL, 0.5. The current study cited Hwang’s research to determine whether the results after central lip lift corresponded to the ideal lip shape from a Korean perspective. After the central lip lift, the LTW, ULR, and VUL significantly increased to 0.39, 0.84, and 0.94, respectively, which were close to the attractive values identified by Hwang et al. (Fig. 4) [4].

The overall average CLA decreased from 101.59° preoperatively to 95.04° postoperatively. The average CLA for the 10 men before surgery was 100.22°, while for the 77 women it was 101.79°. Both average values significantly decreased postoperatively to 91.41º and 96.05°, respectively. In other studies, the ideal CLA value varied, and different patterns for the range of the preferred angle were shown. Powell reported that the ideal CLA was 90° to 120°, and Maran and Lund reported 90° to 105° [19,20]. Armijo et al. [21] reported that the ideal CLA was 93.4° to 98.5° in men and 95.5° to 100.1° in women. The CLA change in our study after the central lip lift was within the ideal ranges (Fig. 5). The central lip lift did not disturb the aesthetic relationship between the nose and lips.

In the authors’ previous study analyzing the results of central lip lifts, complications were relatively minor, with 0.99% of patients requiring revisional treatment due to wound dehiscence and hematoma, and 2.5% requiring revisional surgery due to an asymmetric upper lip [8]. In the current study, no significant complications required revisional treatment. Twelve patients showed minimal wound dehiscence that recovered fully with conservative treatment. Twenty-five patients showed partial exposure of the upper teeth as their upper lip was lifted, which may affect the aesthetic satisfaction of the patients after surgery. The postoperative scars required careful management for aesthetic reasons. Fractional CO2 laser treatments were performed on the visible postoperative scars. Although this study excluded patients who had received intraoperative botulinum toxin injection into the muscle, its effect on scarring reduction has been demonstrated in several studies [5,6,22]. In patients not included in this study, botulinum toxin was injected after central lip lifts to prevent scar enlargement by reducing muscular distortion and minimizing skin tension.

Our study had several limitations. First, there was a difference in the numbers of male and female patients, with only 10 male patients included in the study. Second, the lip-related ratios and CLA were calculated from clinical photographs using Adobe Photoshop 7.0, not from actual patients. Therefore, the measured values might contain errors relative to the actual values. Finally, few previous studies, apart from the research of Hwang et al. [4], could be used as standards for the ideal lip ratio of Koreans.

In this study, we attempted to quantitatively and objectively evaluate the effect of the central lip lift based on the attractive and healthy-looking lip ratio proposed by Hwang et al. [4] The upper vermilion height increased and the philtrum height decreased, approaching the ideal aesthetic ratio with the central lip lift. The CLA did not interfere with the aesthetic relationship between the nose and lips. In conclusion, the central lip lift can be an efficient cosmetic technique to create attractive lips for Koreans.