Factors associated with complex surgical wounds in breast and abdomen: a case-control observational study

ABSTRACT Objective: to identify factors associated with complex surgical wounds in the breasts and abdomen in outpatients. Method: observational case-control study involving 327 patients, distributed into 160 cases (complex surgical wound) and 167 controls (simple surgical wound). Data were extracted from the medical records and a binary logistic regression model was used for analysis, considering a significance level of 5%. Results: the factors associated with greater chance of occurrence of complex surgical wound were 18 to 59 years of age (p = 0.003), schooling < 8 years (p = 0.049), radiotherapy (p < 0.001), hysterectomy (p = 0.003), glycemia (≤ 99 mg/dL) and arterial hypertension (p = 0.033), while quadrantectomy (p = 0.025) served as a protective factor. Conclusion: radiotherapy was the most significant factor for surgical wound complications. Glycemic alteration was an unexpected result and shows the need for further studies related to this topic.

contrast, the determination of risk factors that affect the healing process of surgical wounds is not yet clear in the literature (13)(14) . Among the main causes of Emergency surgery also increases the chances of surgical wound dehiscence (15) .
In this context, the management of the treatment of surgical wounds should include the identification of possible critical factors for healing so as to provide individualized care. Nursing performance has an important role in monitoring the evolution of the wound healing process in general, however, previous studies (10,(16)(17) have shown flaws and lack of knowledge in clinical practice, impacting the quality of care.
In view of the literary scope, while the biological and epidemiological aspects of chronic wounds, especially venous and arterial ulcers, diabetic foot and pressure injury have been extensively researched (9) , there is a lack of national and international information on complex surgical wounds, including guidelines directed at the prevention and treatment of these wounds.
Thus, in order to advance the knowledge on the theme, the objective of this study was to identify factors associated with complex surgical wounds in breasts and abdomen in outpatients.

Method
This is an observational case-control study  year after the surgical procedure (6) .   (Table 3).

Discussion
Surgical wound complications may lead to longer hospitalization, readmissions, and multiple surgeries (3) , with an estimated cost of $6.5 billion in the United States (15) .

The identification of the risk factors for surgical
wound complication, as well as a better understanding of the changes in the wound healing process induced by causative agents allows improvements in healing process outcomes. It is worth noting that multiple local and systemic risk factors are common and act independently or, concomitantly, potentiating the synergic effect of the deleterious action on the wound healing process (13) .
Among the nine independent variables kept in the multivariate model, four referred to the type of surgical intervention. Similar results were identified in previous studies (19)(20)(21) .  (20) . In another study aimed at identifying postoperative complications in patients submitted to hysterectomy, sepsis due to hematoma of the surgical wound was identified in four patients among 98 submitted to abdominal hysterectomy (22) . The routes for performing procedures involving the uterus and appendages are the vaginal, abdominal and laparoscopic routes, and the abdominal approach is most frequent in some centers (20) .
Laparotomy as a risk factor for development of complex surgical wounds was confirmed in other studies (19,23) . Such studies also identified a highest incidence of surgical wound dehiscence to be related with emergency laparotomy, duration of the surgical procedure of more than two hours, abdominal distension, potential contamination, and surgical site infection, the latter being the most common factor.  (21) .
In turn, patients who underwent a quadrantectomy had a lower chance of developing a complex surgical wound. Breast cancer treatment involves two main types of surgery: conservative breast surgery and mastectomy.
The first one, also called quadrantectomy, tumorectomy, culminating in decreased supply of oxygen and nutrients necessary for the healing of tissues that are damaged in the surgical procedure (26) . Although hypoxia attracts the displacement of neutrophils and macrophages, oxygen is important to the healing process because it favors phagocytosis. It is also essential for the deposition of collagen, acting as a substrate in the hydroxylation of proline and lysine residues (12) . When this process does not occur, the surgical wound may present complications, as evidenced in a study performed with patients undergoing laparotomy (27) . Arterial hypertension was associated with a higher probability of occurrence of surgical site infection with early postoperative dehiscence, as well as hypoproteinemia and malignant diseases (27) . Considering However, the time between the end of the radiotherapy and the surgery seems to influence the appearance of the complications. A study (30) performed with 511 patients submitted to abdominal wall reconstruction, of which 381 did not receive previous radiotherapy and 130 received, found no difference between groups in the rate of surgical wound complication.
Another study carried out with 199 patients submitted to breast reconstruction; 100 patients had previously been irradiated and the remainder had not been irradiated.
The study demonstrated that the irradiated patients had more complications such as surgical wound dehiscence and surgical site infection (31) . In both studies (30)(31) , patients had complied with the three-week period of radiotherapy cessation in the preoperative period.
In the present study, schooling of less than Fasting glycemia of less than 99 mg/dL, found in this study as a risk factor for complex surgical wound, contradicts the literature where hyperglycemia appears as a factor that induces complications of complex wounds (11,33) . However, hyperglycemia is present in within four to five days (34) . Furthermore, diabetes mellitus is responsible for microvascular lesions that affect tissue oxygen levels and nutrient supplies; thus, high glycemic levels also affect leukocyte function, essential in the wound healing pathway (12) .
Another contradiction identified in this study concerns the greater susceptibility of surgical wound complication in people aged between 18 and 59 years. However, this result is not unanimous among researchers (19,23) . Previous study showed that patients over 80 years of age presented a higher risk for wound dehiscence, besides a significantly increased risk of second surgery due to superficial infection or bleeding (35) .
With advancing age, the epidermal layer tends to become thinner and the inflammatory, migratory and proliferation responses slower. These patients are also more prone to multiple chronic conditions and to a greater number of associated risk factors, potentiating deleterious action on wound healing pathways (12)(13) .
From another perspective, the impact of the consequences of complex surgical wounds on younger people tends to be more serious compared to the elderly as a result of the greater probability that people in younger age groups are inserted in the labor market, providing the support for their families. This assertion is supported by a recent study (10)  In addition to the findings of this study, probable underestimation of risk factors should be considered as a result of the fact that the data was extracted from a secondary source (medical records). Also, an interesting study (7) conducted in the rural community of Rwanda,  (10,(16)(17) . It is possible to mention the dissatisfaction of patients with complex surgical wounds with the lack of continuity and quality of nursing care in the management of the complex wound, particularly the lack of information about the care to be provided to the wound in post-discharge moments, conflicting pieces of information provided by different healthcare professionals and failure to comply with the frequency of exchange of dressings at home (10) . conditions, exposure to radiotherapy, instructional level and possible social vulnerability for people at productive age. Furthermore, although the present study did not identify an association between obesity and smoking, previous research has shown that weight reduction (13) and smoking cessation (37) favor the healing process of the wound. In this sense, care must be based on a holistic, patient-centered approach (13) .
One of the limitations of this study is the fact that the data came from a single hospital institution, which is a reference in the care of complex wounds. Due to this, the data should be interpreted with caution. Another possible limitation is associated to the reliability of notes in medical records and retrospective data, with the possibility of information bias. These facts made it impossible to identify the cause of surgical wound complication, whether it was hematoma, infection or dehiscence.
Data from a secondary source may have influenced the outcome related to fasting glycemia of less than 99 mg/dL as a risk factor for complex surgical wound.
However, the weaknesses cited do not lessen the relevance of the study because of its contribution to new knowledge on the theme.
This study aims to contribute to a better understanding of the factors related to surgical wound complications. The results obtained support the nursing care to patients who undergo surgical procedures, especially those involving the abdomen and breasts.
In addition, they will support the creation or revision of specific protocols, aiming to reduce the occurrence of