With a continuing epidemiologic trend upward, obesity currently affects approximately 2.1 billion people worldwide.1 , 2 Consequently, obesity management is becoming a main focus for health care providers. In combination with dietary and lifestyle changes, medications and surgical interventions can be used to enable long-term weight loss. However, few drugs are actually effective for facilitating lasting weight loss. In contrast, bariatric surgery is associated with the most significant impact on obesity, resulting also in the reduction of associated comorbidities and even mortality.3 , 4 Therefore, bariatric surgery has grown significantly in popularity within the past decade.3 , 5
Regardless of extensive weight loss, bariatric patients often suffer from a negative body image. The excess skin leads to stigmatization and potentially causes functional disabilities that need to be addressed by means of body contouring surgery.6–8 Multiple studies demonstrate that body contouring surgery including lower and upper body lift, abdominoplasty, breast reduction, mastopexy, brachioplasty, and thigh lift must be seen as the final completion of bariatric surgery and represents a significant step for patients to reach their goals regarding health and well-being.9 , 10 This leads to an upward trajectory in the incidence of body contouring surgery, with 45,000 procedures performed annually in the United States alone.11–13 Concomitant with the increasing incidence of body contouring surgery is the continuous development and optimization of operative techniques.14–17 However, numbers of complications occurring are still high. Therefore, the understanding of factors potentially influencing outcomes is of utmost importance.
Surgical-site infection and associated dehiscence make up 60 percent of the complications that occur in body contouring surgery.17 , 18 This often results in the need for rehospitalization, prolonged medical care, and operative revision.19 To lower the complication rate of these elective procedures, assessment and evaluation of predisposing risk factors and their prevention should be a major goal of modern body contouring surgery. Current literature shows that, besides elevated body mass index, additional predisposing factors may affect the frequency of complications in body contouring surgery. The amount of excised tissue and delayed drain removal significantly increase the number of wound dehiscences and infections.18 , 20 , 21 In addition, hypertension, high patient age, and comorbidities such as diabetes and smoking have been identified to represent predisposing factors for postsurgery complications.18 , 22 Although there is some evidence from other clinical specialties that there might be a seasonal impact on surgical-site infection rates,23–29 this has never been investigated regarding body contouring surgery. Body contouring surgery usually causes large wound areas that require prolonged therapy with compression garments. Furthermore, body contouring surgery procedures are nonemergency operations and thereby can be scheduled flexibly. The sum of these characteristics prompted investigation into whether there is significant increase of postoperative infection during the summer season. This retrospective cohort study on more than 600 patients over a period of 6 years on how seasonal factors influence the incidence of post–body contouring surgery infections at the surgical site will inform patient information, procedure plans, and postsurgical care. This will consequently result in optimized outcomes in the postbariatric patient population.
PATIENTS AND METHODS
All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and national research committee and with the 1964 Declaration of Helsinki and its later amendments or comparable ethical standards (Ethics Commission of Upper Austria study number K-94-15). Patients were assessed regarding demographics, surgical data, and outcomes. Patient data were obtained by chart review, and seasonal data were collected from the Center for Meteorology and Geodynamics in Austria. Data were collected in a password-secured database and rendered anonymous. The database was stored on the server of the Section of Plastic Surgery/Med Campus III, Kepler University Hospital, Linz, Austria, to ensure anonymity of data evaluation and a safe handling of patient-related information. Collected surgical data were compared to seasonal data to discover a potential seasonal influence.
In this retrospective cohort study, we included 602 patients who underwent body contouring surgery at our institution between 2009 and 2015. Performed procedures included lower and upper body lift, abdominoplasty, breast reduction, mastopexy, brachioplasty, and thigh lift (Table 1). The diagnosis of surgical-site infection was made clinically following the Centers for Disease Control and Prevention guidelines—as part of the regular postoperative wound inspection—in case of signs of fatigue, fever, local or spread inflammation, pus, odor, or secretion of the wound.30
To verify our hypothesis, the Fisher’s exact test was used. The potential causal coherence of surgical-site infections and season was calculated by a multiple logistic regression analysis. We defined the tested variables in age younger than 50 years or 50 years or older, body mass index less than 30 kg/m2 or greater than or equal to 30 kg/m2, smoking, duration of surgery less than or equal to 1.5 hours or greater than 1.5 hours, hospitalization less than or equal to 4 days or greater than 4 days, sex (male or female), and season as stated above. Analysis of the anonymized data record took place on the department internal server by use of the programs IBM SPSS Version 22.0 (IBM Corp., Armonk, N.Y.) and Microsoft Excel (Microsoft Corp., Redmond, Wash.).
Of all retrospectively analyzed patients, there were 39 men (6.5 percent) and 563 women (93.5 percent). The average age of the patients was 40 ± 11.2 years (36.3 ± 9.8 years for men and 40.2 ± 11.3 years for women). The average body mass index was 29.1 ± 2.56 kg/m2 for men and 26.8 ± 0.57 kg/m2 for women, resulting in an average of 27.0 ± 0.58 kg/m2 for the study cohort. After division into a warm (June to August) and a cold group (September to May) according to average degrees Fahrenheit and individual operation date, the cold weather group consisted of 466 patients [438 female (94 percent); 28 male (6 percent)] and the warm weather group consisted of 136 patients [125 female (92 percent); 11 male (8 percent)]. The average temperature of the cold weather group (September to May) was 45.45°F (7.47°C) and the average temperature of the warm weather group (June to August) was 67.622°F (19.79°C). We further evaluated our cohorts for comparability regarding age, smoking, body mass index, and distribution of surgical methods. Cohort variation for these factors lies within a 95 percent confidence interval and can therefore be considered as equally distributed. Considered together with the demographic data, this shows that the seasonal groups are composed similarly and there are no significant differences regarding the distribution of sex or duration of operation and hospitalization. The average operation time (independent of the method) in the cold weather group was 1.90 hours for women and 2.16 hours for men, compared with 2 hours for women and 1.98 hours for men in the warm weather group. The average hospitalization time was 5.77 days for women and 6.79 days for men in the cold weather group, compared with 5.59 days for women and 7.18 days for men in the warm weather group.
Breast reduction represents 32 percent of all body contouring operations, the most frequently performed operation in total and of the female subgroup at our institution. As no men underwent a thigh lift, brachioplasty, or mastopexy, breast reduction takes third place among male patients with 12.8 percent. The majority of men were subjected to abdominoplasties (46.15 percent), followed by body lifts (41 percent). The proportional distributions in the female subgroup differ, as abdominoplasties take second place with 28.8 percent followed by body lifts with 14.6 percent; however cold and warm weather groups show a comparable distribution of surgical procedures overall (Fig. 1).
Of a total of 602 patients, we observed 33 surgical-site infections, representing a rate of 5.48 percent. As presented in Figure 2, average temperatures of the investigated years peak in June to August. Surgical-site infection rates also show their strongest ascent in June to July (Fig. 3). Confirming this correspondence, a statistically significant rise of postoperative surgical-site infections could be detected during the summer season (10.29 percent versus 4.08 percent; p = 0.0071), representing an increase of roughly 150 percent. By using a regression analysis, we could further demonstrate a direct correlation between high temperatures and surgical-site infections. We observed that patients operated on in the summer have a 2.693 times higher risk of suffering from surgical-site infection compared with the cold season (Fig. 4). Confirming study results from other groups, we also detected advanced age (>50 years) to be significantly correlated with enhanced risk of surgical-site infections (OR, 2.293). For other previously described risk factors such as smoking (OR, 1.615), hospitalization time (OR, 1.475), duration of surgery (OR, 1.412), and body mass index (OR, 1.108), we found only a trend in our cohort without reaching significance (Fig. 4). We further evaluated humidity as a factor and found an inverse correlation between humidity and temperature (R = 0.71) and no correlation of increased humidity with surgical-site infection incidence in our geographic region. (See Figure, Supplemental Digital Content 1, which shows the relationship of temperature and humidity. Temperature and humidity show an inverse correlation in our climate zone, http://links.lww.com/PRS/C911.)
The seasonal impact on surgical-site infections and their most important pathogens has been studied extensively by other specialties,23–29 but with inconclusive results. Banco et al. discovered in 2002 a seasonal increase of surgical complications apart from temperature-related investigations. The authors linked their results to the arrival of new medical students. The effect of the influx of students on postoperative spinal wound infections during the summer season was designated as “academic year” or “July effect.”24 Reassessing the postulated direct correlation between the arrival of new students and the spinal infection rate, Durkin et al. demonstrated in 2015 an increase of postoperative spine infections in the absence of trainees. This study disproved the “July effect,”23 strengthening again theories correlating surgical-site infections to increased temperatures.
Meanwhile, several other studies investigated the seasonal variation of colonization rate or nonsurgical infections with common pathogens such as Staphylococcus aureus, Pseudomonas aeruginosa, and Klebsiella pneumoniae.31–34 Although those studies differ in the kind of investigated pathogen and infection (bloodstream infection, urinary tract infection, or dialysis-associated peritonitis), they all concordantly note higher infection rates in the summer season.23 , 24 , 31 , 35–37 Summarizing all relevant studies from 1980 to 2012, Leekha et al. performed a systematic review on the seasonal variations of S. aureus, confirming an association of warm weather months with skin and soft-tissue infections caused by S. aureus.38 , 39
These historic and recent studies about a possible seasonal impact on bacterial colonization and negative effects on postoperative outcomes confirm the observations we made with body contouring operations. Corroborating recent studies,28 , 29 our findings show a significant increase of postoperative surgical-site infections in the summer season (June to August). We further evaluated humidity as a factor and found an inverse correlation between humidity and temperature (R = 0.71) (see Figure, Supplemental Digital Content 1, http://links.lww.com/PRS/C911). In central Europe, high humidity is associated with low temperatures, and the other way around. In tropical and subtropical areas, high temperatures are typically associated with high humidity levels.40 Because of this stark contrast, it is difficult to extrapolate our findings to areas without four seasons, such as tropical or subtropical climate zones. Further research should be performed to evaluate our findings for these regions.
Based on the detailed data of patients operated on and treated postoperatively at our department, we have been able to avoid some difficulties that recent large multicenter studies encountered because of working with register databases. Although Gruskay et al. report a significant increase in the absolute number of infections, they estimated a limitation of their findings because of a too-large sample size easily showing small and therefore potentially irrelevant differences.28 In contrast, our results demonstrate a significant increase of 150 percent for surgical-site infections in the warm season in a distinct smaller population of 602 patients. Detecting such a massive difference in a rather small patient cohort underlines the relevance of our findings.
Several studies tried to identify the cause of seasonal variations of surgical-site infections and it seems there are many different interacting factors. Fostered bacterial colonization of skin and soft tissue because of increased mean temperature and humidity is consistently regarded as a main influence.35 , 41 , 42 In addition, Hens et al.43 pointed out the increase in skin-to-skin contact over the summer season as a potential underlying mechanism of increased wound infection (WI) rates. This might directly increase bacterial colonization and is one of the easiest means of bacterial transmission. Apart from advantaging factors for bacterial colonization during the summer time, other causes, such as the increased prevalence of possible portals of entry for bacteria as sores and ulcers, have been identified as more prevalent risks during the summer.44
The average surgical-site infection rate of our population was 5.48 percent, which is similar to the common incidence of postoperative surgical-site infections in a body contouring surgery population.45 Some studies determine the body mass index to be the strongest predictor for the occurrence of a complication,19 , 46 and every body mass index point over 25 has been related to a three-fold increase of the risk for complications.46 Therefore, a preoperative body mass index of 27 kg/m2 is a strong contraindication for body contouring surgery. Because of a lack of official guidelines, however, body mass index cutoffs vary from 27 to 32 kg/m2.47 Our data fail to confirm the general point of view by relating body mass index, time of hospitalization, and surgery to a higher rate of postoperative surgical-site infection, underlining the difficulties of identifying factors significantly impacting the incidence of adverse events following body contouring surgery. We conclude that either the impact of body mass index on surgical-site infection is somewhat overrated, or the average body mass index of 27 kg/m2 in our study cohort is low enough to prevent most weight-related complications. Our findings suggest smoking, duration of hospitalization, and surgery to have a stronger risk correlation with postoperative surgical-site infection than body mass index; however, this could not be proven to be statistically significant either. As it was shown that season has the strongest impact on postoperative surgical-site infection and leads to a 2.693-fold risk elevation, we highly recommend inclusion of seasonality in the planning of body contouring operations. Furthermore, age is a potentially underestimated risk factor because patients older than 50 years are exposed to an approximately two times higher risk for the major complication of a postsurgical surgical-site infection.
Smoking could be statistically determined to be a negative influence and is seen as a predictor for a higher complication rate based on its negative impact on the general state of health and wound vascularity.48 Although some studies found differences in the distribution of complications related to sex,49 it has yet to be proven that there is a risk increase of complications in general. Also, variables such as duration of surgery, combination of procedures, and comorbidities, which are generally accepted as independent risk factors, could not be significantly related to a higher number of complications in our cohort. Somewhat contrasting with our results, Parvizi et al.18 performed a multiple regression analysis to identify possible risk factors and their impact on postoperative surgical-site infection in body contouring surgery. Although body mass index and weight loss were significantly (p = 0.02 and p = 0.05) related to wound healing disorders, only the increasing time of drain removal could be proven to significantly predict surgical-site infections. However, these findings were derived from a much smaller study population, and seasonality was not assessed.
A limitation of our study includes its monocentric study design. Thus, our data and results could potentially be biased by specific factors such as the local medical staff and department environment. Another significant limitation that makes universal result extrapolation difficult is certainly the specific meteorologic conditions every surgeon has to face worldwide.
This study has identified season as the strongest independent risk factor for surgical-site infections after body contouring surgery in a cohort of more than 600 patients, representing the first demonstration of a seasonal variation in postoperative surgical-site infections following body contouring surgery. Body contouring surgery operations are elective procedures, making profound preoperative risk assessment even more important, which further strengthens the significance of our study. In addition, our findings suggest that the guidelines concerning body mass index for this patient cohort might be slightly overrated, and that more important risk factors such as seasonality and age should be emphasized. The understanding of seasonal variety in surgical-site infection is important for creating infection-prevention strategies and must be taken into account during preoperative patient information and surgical planning. Considering the prolonged and complicated healing process and the rising morbidity and costs in case of a postoperative surgical-site infection, we suggest further investigations regarding underlying causes and risks to improve body contouring surgery outcomes.
1. Ng M, Fleming T, Robinson M, et al. Global, regional, and national prevalence of overweight and obesity in children and adults during 1980-2013: A systematic analysis for the Global Burden of Disease Study 2013. Lancet 2014;384:766–781.
2. Smith KB, Smith MS. Obesity statistics. Prim Care 2016;43:121–135, ix.
3. Shukla AP, Buniak WI, Aronne LJ. Treatment of obesity in 2015. J Cardiopulm Rehabil Prev. 2015;35:81–92.
4. Angrisani L, Santonicola A, Iovino P, Formisano G, Buchwald H, Scopinaro N. Bariatric surgery worldwide 2013. Obes Surg. 2015;25:1822–1832.
5. Hsu CC, Almulaifi A, Chen JC, et al. Effect of bariatric surgery vs medical treatment on type 2 diabetes in patients with body mass index lower than 35: Five-year outcomes. JAMA Surg. 2015;150:1117–1124.
6. Sarwer DB, Thompson JK, Mitchell JE, Rubin JP. Psychological considerations of the bariatric surgery patient undergoing body contouring surgery. Plast Reconstr Surg. 2008;121:423e–434e.
7. Choban PS, Jackson B, Poplawski S, Bistolarides P. Bariatric surgery for morbid obesity: Why, who, when, how, where, and then what? Cleve Clin J Med. 2002;69:897–903.
8. Aly AS, Cram AE, Heddens C. Truncal body contouring surgery in the massive weight loss patient. Clin Plast Surg. 2004;31:611–624, vii.
9. de Zwaan M, Georgiadou E, Stroh CE, et al. Body image and quality of life in patients with and without body contouring surgery following bariatric surgery: A comparison of pre- and post-surgery groups. Front Psychol. 2014;5:1310.
10. Ellison JM, Steffen KJ, Sarwer DB. Body contouring after bariatric surgery. Eur Eat Disord Rev. 2015;23:479–487.
11. Wenger R, Constantinescu MA, Kitzinger HB, Frey DM. Expectations from body contouring surgery and body-image satisfaction in post-bariatric patients. J Obes Weight Loss Med. 2015;1:005.
12. Buchwald H, Oien DM. Metabolic/bariatric surgery worldwide 2011. Obes Surg. 2013;23:427–436.
13. Buchwald H, Avidor Y, Braunwald E, et al. Bariatric surgery: A systematic review and meta-analysis. JAMA 2004;292:1724–1737.
14. Schmidt M, Duscher D, Huemer GM. Reply: Concomitant liposuction reduces complications of vertical medial thigh lift in massive weight loss patients. Plast Reconstr Surg. 2017;139:1020e–1021e.
15. Pollhammer MS, Duscher D, Schmidt M, et al. Double-loop dermal suture: A technique for high-tension wound closure. Aesthet Surg J. 2016;36:NP165–NP167.
16. Schmidt M, Pollhammer MS, Januszyk M, Duscher D, Huemer GM. Concomitant liposuction reduces complications of vertical medial thigh lift in massive weight loss patients. Plast Reconstr Surg. 2016;137:1748–1757.
17. Duscher D, Pollhammer MS, Wenny R, Shamiyeh A, Schmidt M, Huemer GM. Barbed sutures in body-contouring: Outcome analysis of 695 procedures in 623 patients and technical advances. Aesthetic Plast Surg. 2016;40:815–821.
18. Parvizi D, Friedl H, Wurzer P, et al. A multiple regression analysis of postoperative complications after body-contouring surgery: A retrospective analysis of 205 patients. Regression analysis of complications. Obes Surg. 2015;25:1482–1490.
19. Kitzinger HB, Cakl T, Wenger R, Hacker S, Aszmann OC, Karle B. Prospective study on complications following a lower body lift after massive weight loss. J Plast Reconstr Aesthet Surg. 2013;66:231–238.
20. Platt AJ, Mohan D, Baguley P. The effect of body mass index and wound irrigation on outcome after bilateral breast reduction. Ann Plast Surg. 2003;51:552–555.
21. Drinkwater CJ, Neil MJ. Optimal timing of wound drain removal following total joint arthroplasty. J Arthroplasty 1995;10:185–189.
22. Neaman KC, Hansen JE. Analysis of complications from abdominoplasty: A review of 206 cases at a university hospital. Ann Plast Surg. 2007;58:292–298.
23. Durkin MJ, Dicks KV, Baker AW, et al. Postoperative infection in spine surgery: Does the month matter? J Neurosurg Spine 2015;23:128–134.
24. Banco SP, Vaccaro AR, Blam O, et al. Spine infections: Variations in incidence during the academic year. Spine (Phila Pa 1976) 2002;27:962–965.
25. Anderson JE. Seasonality of symptomatic bacterial urinary infections in women. J Epidemiol Community Health 1983;37:286–290.
26. Schwab F, Gastmeier P, Meyer E. The warmer the weather, the more gram-negative bacteria: Impact of temperature on clinical isolates in intensive care units. PLoS One 2014;9:e91105.
27. Thornton GF, Fekety FR, Cluff LE. Studies of the epidemiology of staphylococcal infection. N Engl J Med. 1964;271:1333–1337.
28. Gruskay J, Smith J, Kepler CK, et al. The seasonality of postoperative infection in spine surgery: Clinical article. J Neurosurg Spine 2013;18:57–62.
29. Durkin MJ, Dicks KV, Baker AW, et al. Seasonal variation of common surgical site infections: Does season matter? Infect Control Hosp Epidemiol. 2015;36:1011–1016.
30. Berríos-Torres SI, Umscheid CA, Bratzler DW, et al; Healthcare Infection Control Practices Advisory Committee. Centers for Disease Control and Prevention guideline for the prevention of surgical site infection, 2017. JAMA Surg. 2017;152:784–791.
31. Ramos GP, Rocha JL, Tuon FF. Seasonal humidity may influence Pseudomonas aeruginosa
hospital-acquired infection rates. Int J Infect Dis. 2013;17:e757–e761.
32. Cho Y, Badve SV, Hawley CM, et al. Seasonal variation in peritoneal dialysis-associated peritonitis: A multi-centre registry study. Nephrol Dial Transplant. 2012;27:2028–2036.
33. Falagas ME, Peppas G, Matthaiou DK, Karageorgopoulos DE, Karalis N, Theocharis G. Effect of meteorological variables on the incidence of lower urinary tract infections. Eur J Clin Microbiol Infect Dis. 2009;28:709–712.
34. Anderson DJ, Richet H, Chen LF, et al. Seasonal variation in Klebsiella pneumoniae
bloodstream infection on 4 continents. J Infect Dis. 2008;197:752–756.
35. Leekha S, Diekema DJ, Perencevich EN. Seasonality of staphylococcal infections. Clin Microbiol Infect. 2012;18:927–933.
36. Perencevich EN, McGregor JC, Shardell M, et al. Summer peaks in the incidences of gram-negative bacterial infection among hospitalized patients. Infect Control Hosp Epidemiol. 2008;29:1124–1131.
37. Richet H. Seasonality in gram-negative and healthcare-associated infections. Clin Microbiol Infect. 2012;18:934–940.
38. Leekha S, Diekema DJ, Perencevich EN. Seasonality of staphylococcal infections. Clin Microbiol Infect. 2012;18:927–933.
39. Grice EA, Segre JA. The skin microbiome. Nat Rev Microbiol. 2011;9:244–253.
40. Sun D-Z, Oort AH. Humidity–temperature relationships in the tropical troposphere. J Climate 1995;8:1974–1987.
41. McBride ME, Duncan WC, Knox JM. The environment and the microbial ecology of human skin. Appl Environ Microbiol. 1977;33:603–608.
42. Dauwe PB, Pulikkottil BJ, Scheuer JF, Stuzin JM, Rohrich RJ. Infection in face-lift surgery: An evidence-based approach to infection prevention. Plast Reconstr Surg. 2015;135:58e–66e.
43. Hens N, Ayele GM, Goeyvaerts N, et al. Estimating the impact of school closure on social mixing behaviour and the transmission of close contact infections in eight European countries. BMC Infect Dis. 2009;9:187.
44. Skull SA, Krause V, Coombs G, Pearman JW, Roberts LA. Investigation of a cluster of Staphylococcus aureus
invasive infection in the top end of the Northern Territory. Aust N Z J Med. 1999;29:66–72.
45. Cruse PJ, Foord R. A five-year prospective study of 23,649 surgical wounds. Arch Surg. 1973;107:206–210.
46. Arthurs ZM, Cuadrado D, Sohn V, et al. Post-bariatric panniculectomy: Pre-panniculectomy body mass index impacts the complication profile. Am J Surg. 2007;193:567–570; discussion 570.
47. de Kerviler S, Hüsler R, Banic A, Constantinescu MA. Body contouring surgery following bariatric surgery and dietetically induced massive weight reduction: A risk analysis. Obes Surg. 2009;19:553–559.
48. Payne CE, Southern SJ. Urinary point-of-care test for smoking in the pre-operative assessment of patients undergoing elective plastic surgery. J Plast Reconstr Aesthet Surg. 2006;59:1156–1161.
49. Chong T, Coon D, Toy J, Purnell C, Michaels J, Rubin JP. Body contouring in the male weight loss population: Assessing gender as a factor in outcomes. Plast Reconstr Surg. 2012;130:325e–330e.