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Surgical drainage of lactational breast abscess with ultrasound‐guided Encor vacuum‐assisted breast biopsy system

Abstract Lactational breast abscess is a serious complication of mastitis and commonly diagnosed in breast‐feeding women. The traditional drainage of breast abscess was often performed with incisive technique which may result in prolonged healing time, regular dressings, dressing pain, interfering with breastfeeding and unsatisfactory cosmetic outcome. As minimal invasive alternatives to incisive drainage, needle aspiration or percutaneous catheter placement cannot completely replace incisive drainage for the inability to treat large, multiloculated or chronic abscess. Vacuum‐assisted breast biopsy system (VABB) has been successfully applied in the treatment of benign breast diseases with satisfactory cosmetic outcomes. Among VABB devices, EnCor system has some distinctive features that make it an appropriate candidate for the treatment of lactational breast abscesses. In this study, for the first time, we investigated the feasibility, efficacy, and cosmetic results of surgical drainage of lactational breast abscess with US‐guided Encor VABB system. Our data suggests this procedure could serve as a promising alternative for women with lactational breast abscess who require incisive intervention with high cure rate, relatively short healing time, low recurrence rate, few complications, satisfactory cosmetics outcome and without interfering with breastfeeding.

Recently, it has been reported that ultrasound-guided (USguided) percutaneous catheter placement or needle aspiration could be considered as alternative approaches to incisive drainage. [7][8][9][10] Although, it is demonstrated that these minimal invasive procedures can be effective and safe in the treatment of breast abscess of small diameter (<3 cm) or monolocular, these methods still have several potential disadvantages mainly including: lower cure rate and higher recurrent risk compared with incisive drainage, repeat aspirations, difficulty in treating multiloculated or long-standing abscesses.
Therefore, incisive drainage is often inevitable and recommended for the following situations 3 : (a) treatment failure of needle aspiration or catheter drainage; (b) large abscess with a minimum diameter of 5 or more centimeters; (c) multiloculated abscesses; (d) longstanding abscesses.
As a minimally invasive procedure of breast, vacuum-assisted breast biopsy system (VABB) provides more accurate diagnosis and has been successfully applied in the excision of benign breast lesions. [11][12][13][14] Patients show much interest in this procedure for its satisfactory cosmetic outcomes. Compared with percutaneous catheter placement or needle aspiration, VABB system has the following advantages for the treatment of breast abscesses: (a) the viscous pus can be easily aspirated with vacuum suction, which is difficult for needle aspiration; (b) the septa among abscesses can be easily broken with the ultra-sharp cutting tip and the rotating cutter, which is difficult for percutaneous catheter placement, and thus guaranteeing thorough drainage just as incisive drainage; (c) a tissue sample of the lesion area can be obtained concurrently with drainage, which makes the pathologic diagnosis possible and enabling differential diagnosis of inflammatory breast cancer 15 or concurrent breast cancer. 10 In this study, we investigated the feasibility, efficacy, and cosmetic results of surgical drainage of lactational breast abscess with US-guided Encor VABB system. To our knowledge, our data demonstrate, for the first time, that Encor system can be applied in the treatment of breast abscesses with high cure rate, relatively short healing time, low recurrence rate, few complications, satisfactory cosmetics outcome, and without interfering with breastfeeding.

| Patients
From January 2017 to May 2018, a total of 36 female patients in the first people's hospital of Zunyi were included. The diagnosis of breast abscess was made based on the status of breastfeeding, symptoms (breast or nipple pain, malaise), clinical signs (redness, swelling and tenderness in the affected breast; fever), blood test, breast ultrasound, F I G U R E 1 Surgical drainage of breast abscess with different incisions. A, Radial incision: The radial incision was often used in the incisive drainage of breast abscess, which is always associated with prolonged healing time, regular dressings, dressing pain as well as unsatisfactory cosmetic outcome. B, Periareolar incision: The periareolar incision was used in some breast abscess located in the central area with better cosmetic outcome compared with radial incision. However, as is interfering with breastfeeding and emptying breast, some patients may experience relapse of disease because of milk stasis. C, Needle Aspiration: Sometime the pus is too viscous to aspirate by needle that repeat aspirations are often required. For large (>3 cm) or multiloculated abscesses, the effect of needle aspiration is also limited. D, Inframammary fold incision: Breast abscesses can be efficiently drained with inframammary incision using ultrasound-guided Encor vacuum-assisted breast biopsy system. Such incision is far away from nipple without interfering with breastfeeding, minimizing the risk of disease recurrence. Moreover, this minimal invasive incision is hardly visible or even totally invisible as hidden from the natural breast ptosis and US-guided aspirated material. All cases were confirmed with aspiration of pus. Lactational patients with the following conditions were considered to meet the eligibility criteria for surgical drainage of breast abscess with US-guided Encor system: (a) single breast abscess identified on US with a minimum diameter of five or more centimeters; (b) multiple breast abscesses identified on US with a minimum diameter of three or more centimeters; (c) treatment failure with needle aspiration (a maximum of three times without complete resolution). This study was approved by the Ethical Committee of the first people's hospital of Zunyi. Informed consent was obtained in all cases.

| Surgical procedures
All the surgeries were performed by two skilled surgeons with experience of breast ultrasound by using the 7-gauge Encor VABB system.

| Pharmacologic administration and supportive measures
Empiric oral antibiotics were prescribed for all patients, and sensitive antibiotics are administrated according to the results of bacterial cultures. Ibuprofen was prescribed for patients with intolerable breast pain or sustained fever (≥38.5°C for 24 hours). All patients were educated with breastfeeding and skills and the prevention of mastitis. Breastfeeding from the affected breast were encouraged 24 hours after drainage to prevent milk stasis and relapse of the infection. The importance of adequate rest, sufficient fluids, and proper nutrition were also emphasized.

| Evaluation & follow-up
The blood test and breast ultrasonography were repeated 3 days for postoperative evaluation until complete resolution. Pain of the affected breast was evaluated at the surgery day and the 1-3 days after surgery. The pain score was recorded using Numeric Rating Scale (NRS), 16 which 0 stands for no pain and 10 for worst possible pain. The cosmetics satisfaction was evaluated at 8 weeks after the surgery for all cases through telephone or outpatient visits. Score for cosmetics satisfaction was rated as follows: 0 for no satisfaction, 1 for mild satisfaction, 2 for moderate satisfaction, and 3 for pronounced satisfaction. Continuation of breastfeeding was investigated at 3 days, 4 weeks, and 8 weeks after surgery via telephone or outpatient visits.

| Before surgery
Clinical characteristics of included patients are shown in Table 1.

| Surgery
Surgical drainage of lactational breast abscesses with US-guided

| Follow-up
All patients were followed up via telephone or outpatient visits at 1 week, 4 weeks, and 8 weeks after surgery for evaluation of relapse, wound healing, continuation of breastfeeding as well as cosmetic satisfaction (Figure 3). Disease recurrence in our study was defined as redness and swelling, or breast abscess identified on US in the same quadrant of the affected breast.
None of the patients in our study had disease recurrence within postoperative 2 months. All incisions were healed within 1 week after decannulation, and no case of wound infection occured.
The mean score for cosmetics satisfaction was 3.0 ± 0.2, with 97.5% (35/36) of the patients rated for pronounced satisfaction (3 score) and none rated for dissatisfaction (0 score). One patient aged 22 years who has small breasts and without breast ptosis

| Breast abscess
The incidence of breast abscess, which are mostly estimated from retrospective studies and varies widely, ranges from 0.4% to 11% of all lactating mothers. 1,2,17 Milk stasis is the primary cause of mastitis that can sharply increase the risk of developing breast abscesses. 2,5 The main purpose of treating abscesses is to remove the infected fluid as speedily as possible, reducing the pain and relieve the fever or discomfort, thereby allowing patients to continue breastfeeding without interruption. In addition, optimal management of lactational breast abscess should also include effective milk removal, antibiotics, analgesia, and other supportive measures such as sufficient rest, adequate fluids, and proper nutrition. 1,17 Traditional incisive drainage may be the most effective way to treat breast abscess with the highest cure rate and lowest recurrent rate. 4,6,18 However, such procedure often results in unsatisfactory cosmetic outcome with evident scar, great pain associated with regular wound dressing, interfering with breast feeding and prolonged healing time. Hence, the aim of our study was to explore an alternative procedure to incisive drainage with high cure rate, low recurrent risk, and minimally invasive character.

| Needle aspiration
With the popularization of minimal invasive procedures, percutaneous drainage of breast abscesses using needle aspiration with or without US guidance has been studied as an alternative to incisive drainage.
It has been proved that needle aspiration was effective for abscess smaller than 3 cm with shorter healing time and excellent cosmetic outcomes. 18,19 However, the limitations of needle aspiration for breast abscesses cannot be ignored. For abscesses treated with needle aspiration, the cure rate could be low as 59%, 7 while the risk of recurrence could be high as 50% 19 especially for the treatment of multiloculated abscesses 19 , and repeat aspirations were often required. 9 Therefore, surgical drainage cannot be completely replaced by needle aspiration.

| Catheter placement
US-guided percutaneous catheter placement is considered as a min- abscesses, 20 catheter drainage may fail that purpose in some cases of multiloculated abscesses. Moreover, the details of treating multiloculated breast abscesses were little 21 or even never mentioned in previous studies of catheter drainage. It is also reported that catheter drainage is not a definitive procedure for chronic breast abscesses 10 In addition, the catheter of drainage can be occluded by viscous pus or debris of necrotic tissue. Therefore, incisive drainage is often recommended when the abscesses are multiple or chronic 1,3,22 and we have reason to believe that catheter drainage is not the optimal management of breast abscesses.

| Vacuum-assisted breast biopsy
Vacuum-assisted breast biopsy system was developed in 1995 by

| Encor
Several VABB systems are currently available on the market, including EnCor, Mammotome, Finesse, Vacora, and ATEC. Among these devices, EnCor system has some distinctive features that make it an appropriate candidate for the treatment of lactational breast abscesses. It can get all the samples out continuously with probe of variable size and proper vacuum level, thus enabling a significant less duration than Mammotome and Vacora devices. 13,29 Moreover, the vacuum canister in EnCor system provides an extra storage (~1000 mL) for drainage liquid or pus other than the tissue collection chamber, which is of uniqueness among these VABB devices.
Therefore, the EnCor system was chosen to perform the surgical drainage with VABB in our study.

| Inframammary fold incision
The inframammary fold incision is widely used in breast surgery for cosmetic reasons [30][31][32] Incision at this area is often hardly visible or even totally invisible as hidden from the natural breast ptosis.
Moreover, the inframammary incision is also far away from the nipple, minimizing the risk of interfering with breastfeeding. In addition, with the assistance of the extra long VABB probe, abscesses from any area of the affected breast can be easily drained through the inframammary access, while traditional incision that near the abscess cavity may cause serious cosmetic problems. The length of traditional incision for abscess drainage is often no less than 2 cm in order to put a finger in. In our procedure, the access is much less invasive that just measuring just 5 mm long, thus enabling shorter healing time and decreasing the distress of regular dressings.

| Complications
The most common complications after the VABB surgery including postoperative pain, hemorrhaging and hematomas, the incidence of which is mostly associated with the volume of excised tissue 33 However, there are no data regarding the incidence of VABB associated complications in the treatment of breast abscesses. In our study, no patient underwent the condition of hemorrhaging and hematomas, and the postoperative pain is mild and tolerable for the majority of patients. This could be partly explained with the little volume of excised breast tissue. In addition, 5-10 minutes manual compression to the breast was reported adequate for hemostasis, and the majority of hematomas seem not to necessitate further intervention. 33,34 Thus, surgical drainage of breast abscess with US-guided VABB system could be considered as a safe procedure with little postoperative complications, but further data are still required to draw conclusion.

| Milk-fistula
In our study, two patients suffered from sustained massive milk drainage, and they both chose to discontinue breast feeding by using bromocriptine with satisfactory outcomes. Based on the distribution of milk ducts, central lesions seem to be at higher risk for developing milk fistula compared to peripheral lesions. 35 Unfortunately, for VABB drainage or incisive drainage, the incidence and data related to the recovery time of milk fistula are extremely rare. 35,36 This can be partly explained by the fact that only a few patients would choose to continue lactation as milk leakage sharply decreases their life quality. Eric M. Schackmuth reported 37 that a fistula can dry up spontaneously while lactation continues, but this result is not certain and closure can take several weeks.
The only reliable means of stopping a milk leak is to suppress lactation.

| Irrigation
Wound irrigation can remove surface microorganisms and tissue debris which may impede the healing process, and was considered as the most effective method of wound cleansing. 38

| Antibiotics
The optimal duration of antibiotic use is not well studied, but the usual courses are 10 to 14 days. 1,43 However, some evidence-based data suggested that "short may be better". 44 Brad 44 reported that the duration of antibiotic therapy should be customized according to patient's response, and longer courses does not ensure better cure rate. An intervention review conducted by the Cochrane Collaboration 45 showed that breast emptying suggested more rapid symptom relief compared with antibiotics. Therefore, we discontinued antibiotics 48 hours after symptoms resolution.

| Nonpuerperal breast abscess
Breast abscess could also be consequences of nonlactational diseases. The causes of nonpuerperal breast abscess are mostly involved with periductal mastitis and granulomatous lobular mastitis. [46][47][48] Technically, it is absolutely feasible to perform such a surgery on patients with nonlactational breast abscess. However, simple drainage of such abscesses may often result in relapse. 8,49 Drainage of abscess, extended resection, 50 administration of antibiotics 49 as well as steroid 51 are often required for the treatment of nonpuerperal breast abscess. Considering the optimal management of nonpuerperal mastitis is still under controversy, patients with nonpuerperal breast abscess were not enrolled in our study.

| LI M ITATI O N
It is undeniable that this study has a few limitations. First, it is a consecutive cases study rather than randomized comparative trial (RCT), which may lead to a potential selection bias. Second, the number of patients in our study is too small that a definite conclusion cannot be drawn. Therefore, we suggest that our results should be confirmed in larger series and in the form of RCT to ensure reproducibility.

| CON CLUS ION
In conclusion, our data demonstrate that surgical drainage of breast abscess with US-guided Encor VABB system is a feasible and safe procedure with excellent cosmetic outcomes. It could serve as a promising alternative for women with lactational breast abscess who require surgical intervention.