Renpeng ZHOU,Xiujun FU,Yimin LIANG,Chen WANG,Yunliang QIAN,Danru WANG

Department of Plastic and Reconstructive Surgery,Shanghai Ninth People’s Hospital,Shanghai Jiao Tong University School of Medicine,Shanghai 200011,China

SUMMARY Abdominal contour deformities pose an aesthetic challenge to patients with massive weight loss.This article reviews the similarities and differences in obesity between the Asian and Western populations.A comprehensive classification system combining the objective description of structural deformities with patients’ discomfort or physical function is required to classify the abdominal contour deformities.The authors also proposed several controversial issues,including the classification of abdominal deformities,surgical techniques,and complications,providing an evidence-based review for selecting the appropriate surgical method for Asian patients to achieve satisfying clinical outcomes and avoid complications.

KEY WORDS Abdominoplasty; Massive weight loss; Asia; Classification; Complications

The prevalence of obesity is increasing in Asian countries,particularly in China and India,owing to the reduction in physical activity and increased energy-dense food consumed during the socio-economic transition[1,2].In 1975,the 0-7 million obese men and 1-7 million obese women in China accounted for 2.1% and 2.5% of the obese population worldwide,respectively.By 2014,the 43.2 million obese men and 46.4 million obese women in China accounted for 16.3% and 12.4% of the obese population worldwide,respectively.From 1975 to 2014,the obesity rank of Chinese men and women moved from 13th to 1st and 10th to 1st,respectively[3].Abdominal obesity not only leads to cosmetic concerns but also increases the risk of diabetes and other metabolic syndromes,which require medical management.However,obese patients who receive surgical intervention,often experience abdominal deformity,resulting in a significant demand for abdominoplasty to correct redundant skin tissues.

In the current study,we aimed to provide a deeper insight into the current research on abdominoplasty by reviewing the similarities and differences in Western and Asian obese populations.Additionally,we discussed several controversial issues,including the classification of abdominal deformity,surgical technique,and complications.

OBESITY MANAGEMENT AND WEIGHT LOSS

Obesity has been reclassified from a risk factor to a disease state,given its strong association with other diseases,including diabetes,cardiovascular diseases,and metabolic syndrome[4].Obesity in the USA is defined as a body mass index (BMI) ＞ 30 kg/m2.However,compared with the Western population,Asian populations have lower BMIs and are more susceptible to metabolic diseases.A previous survey showed that the prevalence of obese adults in the USA is 30%,while that in China is only 4%; however,Asian populations are characterized by higher abdominal adiposity for a given body weight than Western populations[2].Together with economic development and dietary changes,obesity has posed increasing challenges to Asians in recent years.

Obesity drugs,including phentermine[5]and liraglutide[6],are currently used as adjuncts to lifestyle modification.Pharmacotherapy is occasionally a useful adjunct to achieve weight loss; however,if a 5% body weight loss is not achieved at 3 months,bariatric surgery should be considered.

Bariatric surgery is recommended for patients with a BMI ＞ 32.5 kg/m2and with at least one obesityassociated disease,or for patients with a BMI ＞ 28 kg/ m2with severe type II diabetes or metabolic syndrome.Currently,the main bariatric surgeries are laparoscopic sleeve gastrectomy (LSG)[7]and laparoscopic Roux-en-Y gastric bypass (LRYGB).LSG reduces the volume of the stomach by resection of the fundus and greater curvature of the stomach.LSG maintains the anatomical structure of the gastrointestinal tract and improves glucose metabolism.LRYGB[8]mainly reduces the absorption of food and limits the intake to achieve weight loss; in addition,it can improve glucose and other metabolisms.LRYGB has a higher remission rate for type II diabetes and is the primary choice for patients with moderate or severe reflux esophagitis or metabolic syndrome.

ABDOMINAL DEFORMITY AFTER WEIGHT LOSS

A significant proportion of the obese population has benefited from the steady increase in the rate of bariatric surgery.Bariatric surgery not only leads to significant weight loss but also alleviates various metabolic diseases that accompany obesity.However,most patients experience excess skin following weight loss,especially in women or in those with extreme obesity.

Excess skin and subcutaneous tissue are well-known side effects of massive weight loss (defined as more than 50 pounds of weight) following pharmacotherapy or bariatric surgery[9].Patients tend to feel embarrassed by their appearance because of the loose skin and unexpected folds in the upper arms,breast,inner thigh,abdomen,and the mons pubis[10].Consequently,the incidence of body contouring surgery is increasing to improve the appearance and quality of life of these patients.In particular,the desire for abdominoplasty is rapidly increasing as the abdomen is usually the site of the most severe deformity following massive weight loss.The pathophysiological changes mainly present as skin abrasion,rash,and infection.Abdominal deformities are highly variable; the simplest of which is the traditional pannus,while severe deformity can present as multiple rolls of skin.

INDICATIONS AND TIMING OF ABDOMINOPLASTY

To improve the abdominal contour following bariatric surgery,patients are advised to wait at least 6-12 months until their weight loss has stabilized.Patients should be aged ＞ 16 years before undergoing abdominoplasty.Moreover,the BMI of patients before bariatric surgery should be ＞ 40 kg/m2or ＞ 35 kg/m2and accompanied by metabolic syndrome.Following bariatric surgery,the patients’ BMI is generally ＜ 28 kg/m2at the point when their weight has stabilized[11].

CLASSIFICATION OF ABDOMINAL CONTOUR DEFORMITY

The surgical demand for abdominal deformity makes it necessary to classify abdominal contour deformity.Various classification systems have been proposed that address the deformities of the abdomen[12-14]; however,all these classifications focus on the abdominal contour deformity instead of addressing the deformity postbariatric weight loss.Song et al.[15]proposed a 4-point grading scale,the Pittsburgh rating scale,to rate the abdominal contour deformity after weight loss as follows:0 indicates normal; 1 indicates redundant skin with rhytids or moderate adiposity without overhang; 2 indicates overhanging pannus; and 3 indicates multiple rolls or epigastric fullness.However,Beek et al.[16]believed that the Pittsburgh rating scale is subjective and is insufficient in the abdominal region where the deformity is complex.They applied the Pittsburgh rating scale to photographs of 25 patients and showed them to 13 medical observers.They found that the intraclass correlation of the abdomen was 0.452,which is lower than the threshold value of 0.6 for good validity.Although the 5-group classification developed by Bozola[17]did not mention the abdominal deformity post-bariatric weight loss,the classification is more specific based on the measurable characteristics and tissue layers.Considering the redundant pannus in the anterior abdomen in relation to the fixed anatomic structure,Iglesias et al.[18]proposed an anthropometric classification of the abdominal deformity after massive weight loss.This classification system provides a relative objective measurement using fixed anatomic marks.The objective description of the anatomical deformity is the first step; however,this abdominal deformity is dependent not only on the excess skin and subcutaneous tissues but also on the patients’ complaints and experiences.In addition,Gurunluoglu et al.[19]described a classification that includes functional problems,given the common complaint of redundant skin tissue interfering with activities of daily living.A comprehensive classification system that combines the objective description of structural deformity with patients’ discomfort or physical function is still needed.

SURGICAL INTERVENTION

The aim of surgical intervention is to improve the body contour by removing excess skin and subcutaneous tissue.Various surgical procedures[17,18,20-25],including liposuction,mini-abdominoplasty,umbilical float,traditional abdominoplasty,fleur-de-lis abdominoplasty,and belt lipectomy,have been proposed to reshape the contour.

LIPOSUCTION,ABDOMINOPLASTY,AND LIPOABDOMINOPLASTY

Liposuction[26]is a safe and quick option post-bariatric surgery in patients with a small amount of excess skin.The main advantage of liposuction is the ability to preserve the connective tissue and microvascular network.Liposuction decreases the fat deposited in the abdominal tissue folds but is not ideal for most patients with massive weight loss,as most of them exhibit moderate or severe excess skin and fat tissues.Matarasso[27]divides the abdomen into four liposuction areas that are defined as safe,limited,cautions,and unrestricted areas.The central flap in the cautions area has a relatively high risk of ischemic necrosis as the blood supply is the terminal branch of the superior and inferior epigastric arteries.

Although several surgical methods of abdominoplasty exist,the main and constant principle is to reshape the abdominal wall by removal of excess skin and fat,as well as plication of the rectus abdominis fascia[28].Traditional undermining in abdominoplasty carries a risk of complications,including seroma,hematoma,and necrosis,owing to the damage of abdominal perforating vessels and lymphatic vessels.These complications are often observed in patients with massive weight loss who have considerable amounts of excessive skin and fat and require incisions to be made below the inguinal ligament.

Lipoabdominoplasty was developed to decrease the complication rate and postoperative morbidity[29].Lipoabdominoplasty is not a simple combination of abdominoplasty and liposuction,and Saldanha[29]first used this term in 2001 to standardize the technique with selective undermining,i.e.,approximately 30% of the traditional undermining.Therefore,lipoabdoinoplasty preserves the abdominal blood supply and lymphatic vessels to reduce the complication rate.Swanson[30]conducted a prospective outcome study on 360 patients treated with liposuction,abdominoplasty,and lipoabdominoplasty,and the data indicated that liposuction patients had less pain and recovery time than abdominoplasty and lipoabdominoplasty patients.Although abdominoplasty and lipoabdominoplasty are associated with a longer recovery time and greater pain,the rating was significantly higher than that of liposuction alone; indeed,approximately 51% of patients reported that the amount of liposuction was below their expectation.Compared with traditional abdominoplasty,the combination of liposuction and abdominoplasty is controversial because the additional practice might increase vascular damage.Xia et al.[29]conducted a systematic review and meta-analysis on the safety of lipoabdominoplasty versus abdominoplasty,and their data indicated that lipoabdominoplasty reduces the complication rate in seroma and hematoma.Furthermore,Vieira[31]compared the outcomes of 1,553 patients who underwent abdominoplasty and 9,638 patients who underwent liposuction in combination with abdominoplasty and demonstrated that the overall complication rate of patients in the latter group was significantly lower than that in the former group.The higher complication rate in traditional abdominoplasty alone was due to the damage of perforating vessels in the abdominal wall with large areas of the flap dissection procedure.

FAT LAYERS IN LIPOABDOMINOPLASTY:SUPERFICIAL,DEEP,OR BOTH

The surgical approach to fat removal in the abdominal region remains controversial because scholars have their own understanding of lipoabdominoplasty.The superficial fat layer is between the skin and the fascia of Scarpa,while the deep fat layer is between the fascia of Scarpa and the deep fascia covering the muscles.During their procedures,Saldanha et al.[32-34]preserved the superficial fat below the umbilicus to preserve the abundant terminal branches and lymphatic vessels,decreasing the complication rate,while completely removing the superficial and deep fat above the umbilicus for better repositioning of the umbilicus.They also observed that this technique improved the abdominal contour by avoiding the flat aspect characteristic.Later,Riberiro[35]adopted several modifications aimed at improving the harmony of abdominal profiles.In contrast to the superficial liposuction of the lower abdomen in the original type,Riberiro et al.[35]conducted both superficial and deep liposuction of the upper abdomen and a deep liposuction of the lower abdomen.Their group also performed liposuction of the pubis area to facilitate a harmonious surface between the pubic area and lower abdomen.Swanson[36]argued that the original technique proposed by Saldanha[32-34]would create an uneven surface because of the difference in the upper and lower abdomen in terms of the depth of liposuction of the fat.In the same year,Kim JK et al.[37]introduced a deep-plane lipoabdominoplasty via liposuction of the superficial and deep fat layers of the entire abdomen; they performed this aggressive liposuction in 143 patients,and the overall complication rate was 15.3%.Kim YH et al.[38]conducted a review analysis of superficial liposuction complications in 2,398 cases and reported that superficial liposuction carries a relatively high risk of complications.The main principle of lipoabdominoplasty is preservation of the vascular lymphatic structure in the abdominal wall,to comprehensive data on the abdominal layer,Frank[39]investigate the influence of age,sex,and BMI on the thickness of the abdominal fat layer.The results indicated that BMI positively correlated with the total abdominal wall fat thickness.Furthermore,an increase in BMI correlated positively with a greater increase in the thickness of the deep layer than in that of the superficial layer.In addition,an increase in age was associated with a decrease in the thickness of the superficial layer but an increase in the thickness of the deep layer.These results provide further evidence for deep layer liposuction and aid in the planning of lipoabdominoplasty.

FASCIA OF SCARPA:TO PRESERVE OR REMOVE?

The fascia of Scarpa is a continuous fascial layer that separates the superficial and deep fat in the abdominal wall.Ferreira et al.[40]conducted a macroscopic and microscopic study of abdominal fat and revealed that the thickness of the fat is mainly attributable to the superficial fat layer rather than the deep fat layer.The removal of the superficial fat layer is dominant,while preserving the fascia of Scarpa and the deep fat may have a minor contribution to the abdominal profile.Ferreira[41-42]also conducted a randomized controlled trial (RCT)and prospective study to evaluate the effect of fascia of Scarpa preservation on esthetic results and complications.This RCT provided evidence that the preservation of the fascia of Scarpa has major clinical effects,including a decrease in drain output,earlier removal of suction drains,and a reduced seroma rate.Swanson[36]argued that the preservation of the fascia of Scarpa increases the thickness of the abdominal flap and that preservation may also have a negative effect on the quality of the wound closure.Ribeiro[35]also favors removal of the fascia of Scarpa in the inferior abdomen.In addition,fascia preservation leads to the combination of the fascia of Scarpa with superior tissues,resulting in a bulging contour.To investigate whether the preservation of the fascia of Scarpa preserves the lymphatic vessels,Tourani et al.[43]performed a cadaveric study on abdominal lymphatic vessels in which patent blue V was injected to reveal that the preservation of the fascia does not preserve the lower abdominal lymphatic vessels.In contrast to these findings,Xiao et al.[44]conducted a systematic review of 630 patients to evaluate the efficacy and safety of fascia of Scarpa preservation and suggested that the preservation has a promising effect on reducing the seroma and time for drain output and hospital stay.Additionally,they demonstrated that the preservation has no effect on hematomas,infections,or suture rupture.In a review of 597 abdominoplasty cases,the fascia of Scarpa[45]was shown to be useful in progressive tension sutures to reduce the complication rate.In addition,Ferreira[40]also demonstrated that in obese patients,the thickness of the superficial compartment is constant and the increase in thickness is caused by changes in the deep fat compartment.Further research on the structure of the superficial and deep fat and the fascia of Scarpa in patients with massive weight loss is needed.

COMPLICATIONS

Although abdominoplasty is a relatively safe procedure,the intraoperative and postoperative complications pose challenges for surgeons[46].Common complications include seroma,infection,hypertrophic scarring,and flap necrosis.Compared with patients with non-massive weight loss,the overall complication rates are significantly higher in patients with massive weight loss[47].

SEROMA

Seroma formation is a major postoperative complication due to the substantial accumulation of serous fluid under the abdominal skin flap.Louri et al.[48]reviewed abdominoplasty complications and reported a seroma rate of 18.6%.Other authors[49]argued that a hematoma was the most frequent complication,followed by infection and cutaneous necrosis.Moreover,Botero et al.[50]conducted a cohort study on the complications of body contouring procedures following massive weight loss and found that the most frequent complication was suture dehiscence,followed by seroma.Vidal et al.[46]reviewed 91 articles relevant to abdominoplasty complications and stated that a seroma is the most frequent complication following surgery.A recent evidence-based review[51]also found that a seroma remains the most common post-abdominoplasty complication,with an incidence of 10% to 15%.In addition,Marsh et al.[53]reported that adjuvant liposuction also increases the risk of seroma; however,the incidence can be reduced by preserving the fascia of Scarpa attached to the rectus abdominis and obliquus abdominis[41].The concept of fascia of Scarpa preservation during abdominoplasty was suggested by Le Louarn.Ferreira et al.[41]performed an RCT to evaluate the effect of fascia of Scarpa preservation in patients with abdominoplasty.Compared with conventional abdominoplasty,fascia of Scarpa preservation significantly reduces the seroma rate and drain output[44].When a seroma occurs,multiple percutaneous aspirations can resolve the seroma.

HYPERTROPHIC SCAR

An ideal scar following abdominoplasty should be hardly visible.Traditional abdominoplasty inevitably results in a long horizontal scar,while the fleu-de-lis method has an additional vertical scar as it is used to reduce the vertical and horizontal skin laxity in patients with massive weight loss.To improve scar outcome,Patronella[52]placed the incision 6 cm above the vulvar commissure,2 cm above the inguinal crease,and ascended at -20°-30°to a point 8 cm below the anterior-superior iliac spine.Hypertrophic scarring is an important challenge following abdominoplasty,especially in Asian patients,who have a relatively high tendency to form hypertrophic scars compared with Western patients.To relieve tension from the flap,progressive tension sutures[45]can decrease the risk of hypertrophic scarring by affixing the flap to the deep fascia.Moreover,silicone gel is a common treatment for hypertrophic scars in the early phase,while hypertrophic scarring can be cured using chemotherapy or surgical procedures.

INFECTION

Infection at the operation site generally presents as typical manifestations of erythema,swelling,pain,and elevated local temperature.In severe cases,systemic symptoms may occur,especially in patients with immunosuppression or diabetes.Dutot et al.[49]conducted a retrospective review of 1,128 abdominoplasty cases and showed that obesity was significantly associated with an increased incidence of infections.Smoking and abdominal skin flap necrosis are also associated with a high risk of infection[46].Indeed,it is well known that smoking impairs wound healing and flap survival.Antibiotic treatment should be based on drug sensitivity tests or the empirical use of broad-spectrum antibiotics.

FLAP NECROSIS

The survival of the abdominal flap is a primary concern of surgery,and obesity increases the probability of flap necrosis.The tension burden on the flap and insufficient blood perfusion lead to flap necrosis.Epidermal necrosis is a minor complication that can be restored via reepithelization[48],while subcutaneous tissue necrosis takes several weeks depending on the size and depth of the necrotic area.Progressive tension sutures can reduce the risk of flap necrosis by transferring the tension to a superficial fascial system and reducing the tension on the flap.The incidence can also be reduced by selectively preserving the perforator during flap dissection and avoiding over-pressure bandage.

FUNDING

This work was supported by grants from National Natural Science Foundation of China (81671923) and National Natural Science Foundation of China (81971839).

ETHICS DECLARATIONS

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Competing Interests

The authors declare that they have no competing interests.The authors state that the views expressed in the submitted article are their own and not the official position of the institution or funder.