Chunjie Li,Xiancheng Wang,Ying Liang,Borong Fang,Xiang Xiong,Wenbo Li,Zhongjie Yi,Xianxi Meng

Department of Burn and Plastic Surgery,The Second Xiangya Hospital of Central South University,Changsha 410011,Hunan,China

Keywords:Botulinum toxin A Liposuction Asia Facial contouring Masseter

ABSTRACT Background: Botulinum toxin type A injection,a noninvasive alternative method for treating masseteric hypertrophy,is inadequate for treating patients with a round lower face.This study aimed to investigate the operative technique and clinical results of liposuction followed by botulinum toxin type A injections in patients with masseteric hypertrophy and excessive subcutaneous fat.Methods: Sixty-five patients (50 women and 15 men) were treated using this technique between May 2014 and January 2019.Their mean age was 26.3 years(range,18-35 years)and the mean follow-up period was 13 months(range,8-18 months).Results:All patients achieved slimmer lower cheeks with improved jaw definitions after the procedure.Among the 65 patients,61 (94%) expressed satisfaction with the results and believed that the procedure produced their desired face shape.No major complications were observed.The effect of this combination treatment remained stable for 12 months after the procedure.Conclusion: The authors believe that liposuction followed by botulinum toxin type A injections is an effective technique for the treatment of masseteric hypertrophy and excessive subcutaneous fat.It is also a relatively simple and safe treatment approach.

1.Introduction

The width of the lower face is determined by the size and width of the mandibular bone,thickness of the masseter,and the subcutaneous fat surrounding it.The esthetic ideals of Asians differ from those of the Western population.For example,Asian women tend to prefer oval or almond-shaped faces and dislike a square jaw,which they consider masculine and rough.1This cultural preference has led to the development of various cosmetic procedures that target each of these three components to create a slimmer and more oval face.

Currently,skeletal contouring of the lower face mainly involves resection of the angle or body of the mandible.In 1983,Onizuka et al.2described the first case of skeletal facial contouring with reduction malarplasty in Asians.In 1994,Baek3was the first to systemically describe reduction mandibuloplasty.It has become a routine surgery for Asian patients to achieve a good facial contour.4However,such surgical procedures are complicated and associated with multiple risks.

Botulinum toxin A (BTX-A) injection is an established alternative to surgical contouring of the lower face.In 1994,Moore and Smyth5simultaneously reported the first successful treatment of masseteric hypertrophy using BTX-A.The effect lasted for 6 months with no significant side effects.This report was followed by several subsequent ones that established the treatment efficacy of BTX-A in reducing the masseter volume and improving facial contour lines with few side effects.6-11However,these encouraging results are shadowed by the nonpermanent nature of this treatment modality,which frequently requires repeated injections.

Facial liposuction is primarily used for facial rejuvenation or the treatment of localized adipogenesis in the cervicofacial region.12,13There are no reports in the literature describing the application of facial liposuction in lower facial remodeling for esthetic purposes in Asian patients.

Therefore,the present clinical trial aimed to verify the efficacy and safety of facial liposuction followed by BTX-A injections in Asian patients with a thicker layer of subcutaneous fat and thick masseter muscles.

2.Patients and methods

2.1.Patient data

This study was conducted with strict adherence to the ethical principles of theDeclaration of Helsinki.A total of 65 patients underwent combined facial liposuction and BTX-A injections for lower facial contouring at our hospital from May 2014 to January 2019.Our cohort consisted of 50 women and 15 men.Their ages ranged from 18 to 35 years (mean,26.3 years).All patients presented with benign masseteric hypertrophy and a prominent round lower face.The patients were examined using inspection and palpation before treatment.A skin squeeze test was used to estimate the number of fatty deposits in the cheek area.None of the patients had a history of pain in the masseter,temporomandibular joint disorders,or bruxism.Patients with the following conditions were excluded from the procedure:pregnancy;lactation;allergy to human albumin;history of neuromuscular disorders such as myasthenia gravis,Lambert-Eaton syndrome,and amyotrophic lateral sclerosis;drug treatments with penicillin,quinine,calciumchannel blockers,or aminoglycosides;or psychiatric symptoms.Informed consent was obtained from all patients.

2.2.Facial liposuction

The tumescent technique was applied to remove the facial adipose deposits.Preoperatively,the topographic markings were made over the face to direct fat aspiration(Fig.1).After intravenous sedation with ketamine and a mild tranquilizer,a tumescent mixture of normal saline and 1% lidocaine with 1:100000 epinephrine in a ratio of 4:1 was injected into the subcutaneous tissue in a radial pattern,fanning across the cheek and down into the submental region.Approximately 80-250 mL of the mixture was injected on each side.Subsequently,a stab incision was made at the lobule-cheek interface and a 1-2 mm pocket was dissected at the incision site.A 2 mm liposuction cannula was introduced through the incision and passed in a radial fashion through the deep subcutaneous plane just above the superficial musculoaponeurotic fascia.After uniform suction of the deep subcutaneous plane,the same technique was repeated at a more superficial layer.Care was taken to ensure that the amount of fat suctioned from both sides was comparable and the two sides looked symmetrical.The volume of aspirate from each side was approximately 20-65 mL.After the procedure,a 4×4 gauze pad was used to roll out any remaining blood from under the flap,the stab incisions were closed directly,and a bulky dressing was applied.

2.3.BTX-A injections

Fig.1.The red circles denote the areas of liposuction.

BTX-A was injected bilaterally at 1-2 weeks after liposuction.This method has been described previously.Briefly,the masseter was delineated and marked in preparation for injection.The site of maximum masseter projection was determined during both relaxation and clenching of the lower jaw.Altogether,50 U of BTX-A (Lanzhou Institute of Biological Products,Lanzhou,China) was reconstituted with 1 mL of normal saline and 20 U (0.4 mL) was injected into the site of maximal masseter thickness on each side using a 30-gauge half-inch needle.Fifteen units (0.3 mL) of BTX-A was injected into two lower points equidistant from this site (approximately 1 cm below) with the three injection points forming a triangle(Fig.2).

2.4.Clinical follow-up

Patients returned to the hospital for postoperative evaluation at 1 month and were followed-up for up to 18 months.All patients were asked whether they were satisfied with the treatment results.

3.Results

Fig.2.Three points of BTX-A injections.

The effects of the combination treatment started to become apparent at 3 weeks after the surgical procedure.All patients showed slimmer lower cheeks with improved jaw definitions.Sixty-three out of the 65 patients (97%) expressed satisfaction with the results and believed that the procedure produced their desired face shape.The remaining two patients(4%)believed that their face shape had changed,but the change was less pronounced compared to their expectations.No major complications were observed.One patient developed a seroma on one side of her face after the procedure,which resolved completely without any sequelae after drainage and compression.The follow-up duration for these patients ranged from 1 month to 18 months with an average of 13 months.For all patients,the effect of the combination treatment remained stable for 12 months after the procedure.

3.1.Typical case 1

A 24-year-old woman presented with a square-shaped jaw.On physical examination,her lower face was almost as wide as her upper face.The skin was normal in color and soft to touch.A radiograph of the facial skeleton showed symmetric upper and lower jaws and zygomatic bones.Benign masseteric hypertrophy was diagnosed(Fig.3)and treated with liposuction combined with BTX-A injections.There was little bleeding during the operation,and no complications such as neural damage or hematoma were observed postoperatively.Facial liposuction was performed twice.Altogether,30 mL of adipose tissue was removed on each occasion (total 60 mL).The improvement in the contour was satisfactory for the patient at 12 months after the surgery(Fig.4)and an even more significant result was obtained compared to the patient’s expectations.

3.2.Typical case 2

A 27-year-old woman presented to our hospital with a round face.Physical examination revealed a prominent mandibular angle.The lower face was hemispheric in shape.The skin was normal in color and the texture was firm.Benign masseteric hypertrophy was diagnosed(Fig.5)and treated with liposuction combined with BTX-A injections.Facial liposuction was performed twice.Altogether,25 mL of fatty tissue was removed on each occasion(total 50 mL).There was little bleeding during the operation and the swelling disappeared after 1 week.This patient also underwent chin augmentation with a silicone implant concomitant with the first liposuction.The improvement in the contour was satisfactory,and no recurrence was observed after 10 months(Fig.6).

4.Discussion

In Asian cultures,an oval-shaped or almond-shaped face is desirable.It is a prominent reason for patients to seek lower facial contouring.The standard of beauty emphasizes a smooth and round upper face and a narrower lower face with a pointed chin.A square,round,or pear-shaped lower face is considered undesirable and can result from a prominent zygomatic bone,prominent angle of the mandible,hypertrophic masseter,or excessive fat.In the present study,we reported a technique combining liposuction with BTX-A injections that effectively enhanced the lower facial contour in 65 patients having plump faces or cheeks with benign masseteric hypertrophy.

The use of BTX-A for contouring the lower face offers a simple alternative to surgery.BTX-A,a protein produced by Clostridium botulinum,is an established drug for the treatment of neuromuscular disorders such as strabismus,blepharospasm,hemifacial spasm,and torticollis.14It binds to the presynaptic cholinergic nerve terminals and inhibits the release of acetylcholine into the neuromuscular synapses.The resulting paralysis leads to functional denervated muscle atrophy.Since Moore and Smyth5first reported its use in the treatment of masseteric hypertrophy,several large prospective studies and case series have assessed its efficacy.Most of these were able to achieve a maximum masseter volume reduction of 21.4%-31.0%.6-10Most of the studies reported that this maximum effect occurred at 3 months before the volume was regained gradually unless a second injection was administered.No major complications were observed.Minor side effects included ecchymosis and swelling at the injection site,decreased masticatory force,change in facial expression,sunken cheek,changes in the taste sensation,speech disturbance,muscle pain,prominent zygoma,facial asymmetry,disappearance of facial dimples,mild headache,and dry mouth.7-10,15-17The majority of these side effects resolved within 8 weeks.To minimize the side effects,we should investigate the minimum effective dose of BTX-A,define benign masseteric hypertrophy,and research new safety technologies.Recently,a novel ultrasonography-guided injection technique for BTX-A was reported.By visualizing the masseter,this novel technique suggested that the deep inferior tendon was more effective and could prevent the occurrence of paradoxical masseteric bulging when compared with conventional blind injections.18

BTX-A injection is a simple technique having few side effects and promises a rapid return to daily life.Kim et al.9analyzed 383 patients and observed that patients were more likely to be satisfied with the result if they had a thick masseter,an even facial contour line with few curves,and a relative lack of subcutaneous fat in their faces.Subsequently,they performed liposuction over the chin contour area in three patients who showed little change due to thicker fat tissues.12Liposuction in the cervicofacial region is primarily used for facial rejuvenation.Another use of liposuction is in the treatment of localized adipogenesis.Sun et al.13reported successful application of laser lipolysis followed by liposuction to treat localized adipogenesis in 16 Asian patients.Compared to Caucasians,Asians have greater accumulation of adipose tissue in the malar region.19Facial liposuction can potentially reduce this adipose tissue via aspiration of the subcutaneous fat.There are no reports in the literature describing the use of liposuction in lower facial contouring for solely cosmetic purposes.Wong et al.20reported successful use of combination treatment with BTX-A;phosphatidylcholine/deoxycholate lipolysis;and chin,cheek,and nose hyaluronic acid augmentation to improve facial contour in a 20-year-old Asian woman.The theory behind this approach was based on the fact that BTX-A alone cannot produce slimmer lower faces in patients with excessive subcutaneous fat in the lower jaw region.Our approach was based on the same principle and had advantages including good efficacy,stable results,simple technique,and low morbidity.It is debatable whether liposuction shows better results compared to lipolysis using phosphatidylcholine.Although lipolysis is generally considered less invasive,it can result in localized pain,infiltrative edema,erythema,localized heat,itching,and bruises at the treatment site,which can last from 4 to 14 days.21Recently,Wen et al.22reported that combined application of liposuction and fat grafting can effectively and easily improve the facial contour.

Fig.3.Pretreatment appearance.

Fig.4.Appearance at 12 months after the treatment.

Fig.5.Pretreatment appearance.

Fig.6.Appearance at 10 months after the treatment.

To meet the needs of different patients,BTX-A has also been used for facial contouring in combination with other less invasive operative procedures.Recently,a clinical study combining BTX-A and hyaluronic acid met the expectations of patients seeking cosmetic improvement.1BTX-A injection combined with tridimensional fat grafting to the chin has also exhibited very good therapeutic effect.23In addition to traditional liposuction,radiofrequency-assisted liposuction has garnered considerable interest.Radiofrequency technology has been used for body and facial contouring in patients with excess fat and mild to moderate skin laxity.24It is considered a simple and minimally invasive tool that is more accurate than previous technologies.25In 2020,a clinical study reported that subcutaneous radiofrequency after liposuction was an effective treatment for face and neck skin tightening.Altogether,227 patients received this two-step treatment and 89.1% of the patients showed moderate to excellent results without major complications.26In 2020,a second-generation radiofrequency-assisted liposuction device achieved significant reduction in complication rates both statistically and clinically when compared with a first-generation device.27Electrochemolipolysis is a low-cost alternative that has also shown potential in nonsurgical fat reduction.28Therefore,the choice of facial contouring treatment should depend on the requirements of patients seeking cosmetic improvement.The strategy for each specific operative procedure should be determined based on the specific situation of the patient.Some novel technologies such as the MD code approach29and the“anatomy of beauty”face technique30have been used in facial contouring.Further development of these technologies would be more conducive to formulating individualized treatment plans according to the strengths and weaknesses of patients’ facial anatomy.In the present study,we proved that BTX-A combined with facial liposuction is an effective method for Asian patients with a thicker layer of subcutaneous fat and masseteric hypertrophy.

5.Conclusion

Liposuction combined with intramuscular injection of BTX-A is effective in lower face contouring by removing subcutaneous fatty tissue and reducing the bulkiness of the masseters.Although one patient developed seroma on one side of her side after treatment,it resolved completely with proper management.Treatment success depends on careful preoperative evaluation of facial appearance to distinguish factors related to bone anatomy from a thick masseter and excessive subcutaneous fat in patients who present with square or round lower faces.Further studies are needed to evaluate the selection criteria and longterm effects of this combination treatment.

Ethics declarations

Ethics approval and consent to participate

The need for ethical approval was waived due to the retrospective nature of this study.All participants provided written informed consent before enrolment in the study.

Consent for publication

All patients included in this study provided written informed consent to publish the data presented in this study.

Competing interest

The authors declare that they have no competing interests.

Authors’ contributions

Li C:Writing-Original draft,Data curation.Wang X:Methodology,Supervision.Liang Y:Writing-Reviewing.Fang B:Investigation.Xiong X:Validation.LiW:Software.Yi Z:Writing-Editing.MengX:Conceptualization.

Acknowledgements

This study was supported by the National Natural Science Foundation of China(grant no.81671964,2017/01-2020/12).