Obesity and Complications in Mammoplasty: A Retrospective Review in an Obese Patient Population

Background:

With trends of obesity increasing, plastic surgeons are resecting larger weights from larger patients. Published literature has demonstrated the association between body mass index (BMI) and resection weight to postsurgical complications; however, these relationships are unclear in a population that is primarily overweight or obese. Our study examines these relationships to assist plastic surgeons in identifying high-risk patients and discussing preoperative measures to decrease the likelihood of surgical complications.

Methods:

We performed a retrospective electronic medical record review of a cohort of 182 bilateral reduction mammoplasty procedures performed at a single institution over a four-year period. Patient data were obtained and correlated with postoperative complications.

Results:

Within our identified patient cohort, 95% were classified as either overweight or obese. Incidence of complications was 51%, with wound dehiscence having the highest incidence of 36.26%. Using a multivariate regression, our analysis found statistical significance between surgical complications and both smoking status and BMI (P = 0.042 and P = 0.025, respectively). Smokers had an increased risk of complications with an odds ratio of 5.165. For every additional 1 kg/m2 increase in BMI, the odds for surgical complication increased by 1.079. In a subanalysis focusing on wound dehiscence, the use of postoperative drains was a protective factor (P = 0.0065).

Conclusions:

Our study population, with a high average BMI and smoking status, demonstrated a statistically significant increase in postsurgical complications. These findings will help counsel obese patients preoperatively on their increased risk of complications.

Takeaways

Question: Are patients with higher BMIs at greater risk for postsurgical complications?

Findings: Postsurgical complications were statistically greater in patients with higher BMIs and patients who were active smokers. Incidence of complications was 51%‚ with wound dehiscence having the highest incidence of 36.26%.

Meaning: With trends of obesity increasing within the United States, plastic surgeons are facing the challenge of resecting larger weights from larger patients. Patients with higher BMIs increase the risk of postsurgical complications. The findings demonstrate that plastic surgeons should be transparent about the increased risk of complications when operating on their patients with larger BMIs. Additionally‚ presurgical counselling can include lowering BMI and quitting smoking to decrease complication risk.

INTRODUCTION

Obesity has grown to be one of the largest public health concerns in the United States, stemming from lifestyle, health-related, and environmental factors leading to an increase in poor eating and sedentary behaviors.¹ Behind cigarette smoking, obesity is the second leading cause of preventable death in the United States.² Rates of obesity have increased by 40% between 1990 and 2015 and are projected to reach near 75% of all Americans by 2030.³ While body mass index (BMI) of Americans has been increasing, resection weights in mammoplasty reduction cases have been increasing in parallel.

In the 1990s, resection weights greater than 700 g per breast were considered large reduction cases; however, the average size of breast reductions has significantly increased with increasing weight, requiring modifications and precautions for plastic surgeons to identify “large reductions” that may have greater surgical risk.⁴ Prior research has demonstrated that mammoplasty operations on patients with higher BMIs are at increased risk for postsurgical complications.^5–7 The most common postsurgical complications after mammoplasty are infection, fat necrosis, seroma, loss of nipple, decreased nipple sensation, and hematoma.⁸ However, there is limited research analyzing a primarily overweight or obese patient population to quantify the association between BMI and rates of postoperative complications after bilateral reduction mammoplasty for treatment of breast hypertrophy. In this study, we examined the postoperative complication rates after bilateral reduction mammoplasty at a single institution with an above-average patient BMI as a function of patient age, BMI, smoking status, and resection weight.

METHODS

We performed a four-year retrospective review of our facility’s electronic medical record system to analyze complication rates after bilateral mammoplasty. A cohort of 182 mammoplasty reductions, performed by two surgeons, was identified and included in our study. The following demographic variables were obtained from patients’ clinical and operative notes: age, BMI at operation, smoking status, total surgical resection weight, clinically-relevant comorbidities, and surgical technique. BMI was recorded numerically and by WHO BMI categories: normal (18.5–24.9), overweight (25–29.9), obesity class I (30–34.9), obesity class II (35–39.9), obesity class III (>40); however, only numeric BMI was used in statistical analysis. The WHO BMI categories are to visually demonstrate proportions of different weight classes within the patient population. Complications postoperatively included the following: infection (diagnosed within 30 days of operation), dehiscence requiring wound care, nipple loss (full and partial), sensation loss to areola, seroma, hematoma, reoperation, and scar revision (including keloid). Early complications were designated as hematoma, full and partial nipple loss, infection, and wound dehiscence. Late complications were designated as sensation loss, hypersensitivity, reoperation, scar revision, keloid, and seroma. A seroma was classified as patient developing a mass filled with clear fluid after the surgical operation that required drainage. A hematoma was classified as a mass of clotted blood within the breast after operation that may or may not have required drainage. Lastly, reoperation was classified as any complication that required the patient to undergo general anesthesia in the operating room for a surgical correction. A multivariate regression model in SPSS (version 28.0.1.0) was conducted to determine increased risk of surgical complications in relation to patient demographics. A multivariable regression model was selected to limit potential confounding variables. Statistical significance was designated at a P value of less than 0.05.

RESULTS

Of the 182 patients included in this study, 173 were classified as overweight or obese (95%), designated as WHO BMI categories overweight, class I, and class II. Thirty-three (18%) of those patients were categorized as morbidly obese, designated as WHO BMI category class III (Figure 1). Thirty-eight (21%) of the patients were current or previous smokers. Demographics and resection weight are presented in Table 1.

Fig. 1.

Patient distribution of weight categorized by WHO BMI categories.

Table 1.

Demographic and Resection Weight Data from 182 Patients Receiving Bilateral Mammoplasty Reduction

	Mean	Range
Age (y)	36.4	17–72
BMI (kg/m1)	34.1	21.3–53.6
Resection weight (g)	736.0	102–2856

The patients had a variety of comorbidities that directly affect postsurgical complications, such as increased risk of infection, wound dehiscence, or seromas and hematomas. The median number of clinically-relevant comorbidities was zero; however, the number of comorbidities ranged from zero to five. Hypertension (26.92%), diabetes (7.69%), and hypothyroidism (6.04%) were the most prevalent comorbidities in the patient population (Table 2).

Table 2.

Prevalence of Different Comorbidities that Affect Postoperative Surgical Outcomes in Mammoplasty

Comorbidity	Proportion
Hypertension	26.92%
Diabetes	7.69%
Hypothyroidism	6.04%
Anemia	4.95%
Hyperlipidemia	3.85%
Sickle cell	1.65%
Previous breast surgery	1.65%
Hypercholesterolemia	1.65%
DVT	1.65%
Thrombocytopenia purpura	1.10%
Hashimoto thyroiditis	1.10%
COPD	1.10%
CHF	1.10%
Cardiac event	1.10%
Sarcoidosis	0.55%
Metabolic syndrome	0.55%
Lymphedema	0.55%
Lupus	0.55%
Hydronephrosis	0.55%
Hepatitis C	0.55%
Breast cancer	0.55%

Multiple breast reduction techniques were utilized in this cohort. An inferior parenchymal pedicle with a wise pattern skin reduction was the most common surgical technique utilized (n = 141, 78%). The remaining procedures were divided by superior medial parenchymal pedicle with a wise pattern skin reduction (n = 19, 10%), superior parenchymal pedicle with a wise pattern skin reduction (n = 19, 10%), free nipple graft (n = 2, 1%), and medial pedicle with a wise pattern reduction (n = 1, 1%). Distribution of surgical techniques by WHO BMI category is shown in Figure 2.

Fig. 2.

Frequency of surgical techniques by WHO BMI categories.

The overall complication rate was 51%. The complication with the highest frequency was dehiscence (n = 66, 36.26%) followed by infection (n = 22, 12.09%) and sensation loss over the areola (n = 9, 4.95%). Early complications accounted for 81% of all complications, whereas late complications were 19%. The frequency of complications is presented in Figure 3.

Fig. 3.

Frequency of postsurgical complications.

All demographic and surgical factors were assessed with a multivariate statistical analysis to determine their impact on surgical complications (Table 3). Age, resection weight, and surgical technique were not statistically significant for increased incidence of complications (P = 0.37, P = 0.07, P = 0.739); however, both smoking status and BMI were statistically significant for increased incidence of complications (P = 0.042, P = 0.023). Patients who smoke had 5.165 greater likelihood of having a postsurgical complication compared with those patients who do not smoke or use tobacco. Higher BMIs increased the risk of having a complication, with an increase of 1.079 in odds for each additional point of BMI increase.

Table 3.

Multivariable Linear Regression Analysis to Test the Independent Relationship between Age, BMI, Smoking Status, Resection Weight, and Surgical Technique to Postsurgical Complications

Variables	β-coefficient	SE of Estimate	95% CI	Odds Ratio	P
Age	–0.010	0.012	0.967–1.013	0.990	0.37
BMI	0.076	0.033	1.011–1.151	1.079	0.023
Smoking status	1.642	0.808	1.061–25.15	5.165	0.042
Resection weight	–0.001	0.000	0.998–1.000	0.999	0.07
Surgical technique	0.494	1.485	0.089–30.087	1.640	0.739

As seen in Figure 3, the most common complication reported was wound dehiscence. A subanalysis using a multivariate statistical analysis was used to determine the impact of demographic and surgical factors on wound dehiscence as a postsurgical complication (Table 4). Age, BMI, and resection weight were statistically significant for wound dehiscence postoperation (P = 0.0299, P = 0.0065, P = 0.0433). Additionally, the use of drains was a protective factor in preventing wound dehiscence postsurgery (P = 0.0065). Smoking status and surgical technique were not statistically significant for wound dehiscence (P = 0.9902, P = 0.9545).

Table 4.

Multivariable Linear Regression Analysis to Test the Independent Relationship between Age, BMI, Smoking Status, Resection Weight, Surgical Technique, and Use of Drains to Postsurgical Wound Dehiscence

Variables	β-coefficient	SE of Estimate	95% CI	P
Age	–0.006	0.0025	–0.0106 to –0.0005	0.0299
BMI	0.019	0.0072	0.0056 to 0.03405	0.0065
Smoking status	–0.002	0.1405	–0.2789 to 0.2755	0.9902
Resection weight	–0.0002	0.00009	–0.0004 to –0.000006	0.0433
Surgical technique	0.0028	0.0491	–0.0941 to –0.0996	0.9545
Drains	–0.2215	0.0805	–0.3803 to –0.0626	0.0065

DISCUSSION

Controlling for various demographic and lifestyle characteristics, complications are higher in patients who have larger BMIs and are current or former tobacco users. This is consistent with the previously published literature from other facilities.^8,9 This increased risk is important to understand in the community our institution serves, as the patient population has higher than average rates for both smoking and BMI.^7,10

Wound healing and dehiscence were the most common complications to occur in our patient cohort, which is representative of what has been previously published in similar literature.^5,11 The pathophysiology of obesity is consistent with increased incidence of dehiscence due to vascular insufficiency, oxidative stress, alteration in immune mediators, and nutritional deficiencies.^12,13 More severe complications (such as hematomas and seromas) remained rare, with rates comparable to the reported incidences of other facilities.¹⁴ This rarity of seromas, even with high levels of obesity, is important to plastic surgeons, as increases in BMI often lead to higher volume of breast tissue resection, meaning a larger surface area of dissection. Current published literature is divided on whether resection weight is correlated with a higher incidence of surgical complications.^15–18 Our study demonstrated that larger volumes of resection were not associated with a higher risk of complications, indicating that other clinical or physiological factors associated with obesity are influencing higher rates of surgical complications. Our results allow plastic surgeons to operate without worry that a larger resection weight alone will increase the risk of a postsurgical complication. Additionally, it is important to assure plastic surgeons that specific surgical techniques are not correlated with increased risk of complication, a finding that has been supported by other published studies.^8,19

In the subanalysis focusing on wound dehiscence, our results challenge the current literature. Firstly, our study determined that drain usage was a protective factor, which challenges previous literature and clinical recommendation that have shown no difference between wound dehiscence and drain usage.^20,21 In our facility, some surgeons consistently use drains, whereas others are selective about drain use, basing their decision to use a drain on resection volume and nipple elevation. One possible explanation for the reduction in dehiscence with drain use could be a reduction in postoperative edema early after surgery. In addition to drains, resection weight, BMI, and age were associated with rates of wound dehiscence. These results align with other studies that have documented the association between obesity and resection weight with wound dehiscence.^6,22,23 Obese patients often require larger reductions, which may require greater dissection, potentially larger dead space, and more postoperative edema. Increased operative times for larger reductions could also increase inflammatory response and increased postoperative swelling. Some or all of these factors may lead some surgeons to use drains in the hopes of reducing postoperative edema and possible wound dehiscence. We frequently use drains for all reductions over 1000 g and selectively for those between 500 and 1000 g. For those less than 500 g, we often do not leave drains.

Lastly, our study challenged that smoking increases rates of wound dehiscence, which has been reported in multiple publications.^24–27 With our patient population having higher rates of current smokers compared with the national average, these results may demonstrate the possibility of conducting a needed breast reduction operation while the patient is actively or has just recently stopped smoking.

Unlike many other studies, we utilized a multivariate analysis to understand demographic and surgical relationships independently and simultaneously, decreasing the likelihood of a confounding effect. Clearly identifying the association between BMI and surgical complications allows plastic surgeons to understand which patients are at high risk, and proactively work with those patients to lower the risk of complications by decreasing weight or stopping the use of tobacco before conducting a mammoplasty. Currently, our facility recommends to patients that they have a BMI less than 40 and have not smoked for a minimum of 3 months before pursuing an elective mammoplasty. However, based on these study findings, our surgeons are willing to make case-by-case exceptions for operating on individuals with higher BMIs and with a more current smoking history.

CONCLUSIONS

As obesity rates in America continue to climb, plastic surgeons will be asked to resect larger volumes of breast tissue on larger patients. Previous studies have produced conflicting results on the independent association between BMI and resection weights and the development of postoperative complications. Our study, with one of the highest mean BMIs reported for a patient cohort (34.1), demonstrated a statistically significant increase in risk of complications for increasing BMI. We did not, however, find a significant increase in risk of complications based on resection weight. We believe that these findings will help counsel obese patients preoperatively on their increased risk of complications, and reassure plastic surgeons undertaking large volume reductions to achieve a desired breast size.