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Table of Contents
ORIGINAL ARTICLE
Year : 2020  |  Volume : 3  |  Issue : 1  |  Page : 4-10

Mesh salvage following deep surgical site infection


1 Department of Surgery, Oregon Health and Science University, Portland, OR, USA
2 Department of Surgery, Penn State Health Milton S. Hershey Medical Center, Hershey, PA, USA

Date of Submission08-Oct-2019
Date of Acceptance14-Oct-2019
Date of Web Publication17-Feb-2020

Correspondence Address:
Dr. Eric M Pauli
Department of Surgery, Penn State Health Milton S. Hershey Medical Center, 500 University Drive, MC H149, Hershey, PA 17033
USA
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/ijawhs.ijawhs_47_19

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  Abstract 


BACKGROUND: Following herniorrhaphy, deep surgical site infections with mesh involvement (dSSI-MI) traditionally necessitate mesh removal, putting patients at risk for hernia recurrence. There is no consensus about managing infected mesh, as salvage strategies are poorly reported. We describe our outcomes following dSSI-MI at two high-volume hernia centers.
MATERIALS AND METHODS: A retrospective review of hernia repairs complicated by dSSI-MI with subsequent salvage attempt was undertaken. Outcome measures included duration of antibiotic use, recurrent dSSI-MI, need for mesh excision, postoperative complications, and hernia recurrence.
RESULTS: Thirteen patients underwent attempted mesh salvage (female = 8, median age = 64, and median body mass index = 30.6). 62% had an average of 1.5 prior mesh repairs, and 23% had prior surgical site infection. Twelve underwent open ventral or parastomal hernia repairs, while one patient had a prophylactic mesh augmentation. Three cases required concomitant bowel surgery. Eight dSSI-MIs resulted from gastrointestinal tract complications. All patients received antibiotics for median of 17 days. 92% required operative management of dSSI-MI (100% incision and drainage, 66% debridement of soft tissue). Negative-pressure wound therapy (NPWT) was utilized in 92% for an average of 26 days. One patient was successfully managed without an operation. With a median follow-up of 34 months, there were two recurrent hernias, only one requiring repair.
CONCLUSIONS: Despite requiring significant postoperative care (reoperations, prolonged antibiotics, and NPWT), mesh salvage without complete explantation is feasible following dSSI-MI, with a low rate of recurrent hernia formation or long-term infections. Salvage attempts were undertaken primarily in patients with retromuscular macroporous polypropylene, suggesting that repair type and mesh choice influence the decision-making for salvage.

Keywords: Abdominal wall reconstruction, mesh infection, mesh salvage, ventral hernia repair


How to cite this article:
Siegal SR, Morrell DJ, Orenstein SB, Pauli EM. Mesh salvage following deep surgical site infection. Int J Abdom Wall Hernia Surg 2020;3:4-10

How to cite this URL:
Siegal SR, Morrell DJ, Orenstein SB, Pauli EM. Mesh salvage following deep surgical site infection. Int J Abdom Wall Hernia Surg [serial online] 2020 [cited 2023 Jun 4];3:4-10. Available from: http://www.herniasurgeryjournal.org/text.asp?2020/3/1/4/278495




  Introduction Top


Mesh reinforcement is considered standard for the vast majority of ventral hernia repairs (VHRs), as mesh prosthetic use reduces the rates of postoperative hernia recurrence.[1] Unfortunately, the benefits of mesh are somewhat offset by potential risk, notably the 5%–10% incidence of mesh infection.[2]

Deep surgical site infections with mesh involvement (dSSI-MI) traditionally necessitated mesh removal, as high as 90% in some series.[3],[4] Such infections may require prolonged antibiotics, frequent wound care, and place patients at risk for hernia recurrence and complications.[3],[5] This likely leads to longer hospital length of stay and increases healthcare costs.

There is no consensus about mesh salvage strategies, and current literature has a heterogeneous population of patients, mesh types, and mesh implant locations.[6],[7],[8],[9] This manuscript describes pooled outcome data from two high-volume hernia centers utilizing similar herniorrhaphy technique and dSSI-MI salvage strategies.


  Materials and Methods Top


A retrospective review of prospectively maintained databases was undertaken at two high-volume hernia centers from 2012 to 2018 to identify patients who underwent attempted mesh salvage following dSSI-MI. Data were collected from Oregon Health & Science University in Portland, Oregon and from Penn State Health Milton S. Hershey Medical Center in Hershey, Pennsylvania.

Patients were included if they were older than 18 years, underwent VHR with mesh for their index operation, had a defect size > 2 cm × 2 cm, and developed a postoperative dSSI-MI. dSSI-MI were defined as suppurative mesh infections with fluid collections surrounding the prosthetic, mesh erosion, or mesh-related enteric fistulas [Figure 1]. The dataset included ventral, incisional, and parastomal hernia repairs as well as prophylactic mesh augmentation (PMA) for hernia prophylaxis. Inguinal and paraesophageal hernia repairs were excluded from the analysis. Superficial infections (cellulitis) and suppurative fluid collections not in contact with the mesh were excluded. Primary outcomes included percent of mesh salvaged, hernia recurrence, and reoperation. Secondary outcomes of interest were postoperative morbidity and mortality. Continuous and ordinal variables were summarized in terms of the medians and standard deviation (SD), while categorical variables were described using frequencies and percentages.
Figure 1: Deep surgical site infections with mesh involvement on computed tomography scan as defined by suppurative infection (red arrows) in contact with prosthetic mesh (yellow arrow)

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  Results Top


During the study period, thirteen patients met inclusion criteria (female = 8, median age = 64, median body mass index = 30.6) [Table 1]. All 13 dSSI-MI patients underwent attempts at mesh salvage, treated conservatively without immediate surgical intervention for mesh removal. Eight patients (62%) had an average of 1.5 prior mesh repairs. Within the study group, 30% of patients were active smokers. Three patients (23%) had prior surgical site infections (SSIs), two of which involved methicillin-resistant Staphylococcus aureus.
Table 1: Patient demographic and prior hernia data

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For the index hernia operation, six patients underwent ventral incisional hernia repair, while four patients underwent parastomal hernia repairs [Table 2]. Two patients had combined ventral incisional and parastomal hernia repairs. One patient underwent PMA after having an open abdomen following trauma (patient #5). A transversus abdominis release was performed in 77% of cases, while the remaining required no myofascial advancement. The average overall hernia area was 280 cm2. Macroporous polypropylene mesh was used in 85% of cases (of these, 82% placed in retromuscular space). Poly-4-hydroxybutyrate mesh was used in the remaining 15% (one in the retromuscular space, another placed as an onlay). Three cases required concomitant bowel surgery (two partial colectomies) and one patient underwent hip fixation and gastrostomy placement due to trauma (patient #5).
Table 2: Patient Hernia Repair Surgical Data

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All patients included in our study developed a dSSI-MI [Table 3]. Median follow-up time from the index operation was 34.2 months (SD: 17 months, range: 1–73.2 months). Eight infections (62%) resulted from gastrointestinal tract complications (4 ostomy-related complications, 1 colonic anastomotic leak with fistula, 1 coloatmospheric fistula, 1 gastrostomy tube leak, and 1 gastric perforation). The remaining five cases of dSSI-MI were due to deep surgical site infections (dSSI), either de novo infections or secondarily infected hematomas or seromas. The majority of patients (92%) did require operative management of dSSI-MI; of which, 100% required incision and drainage of the suppurative infections, while 66% required debridement of soft tissue. Negative-pressure wound therapy (NPWT) was utilized in 11 patients (92%) for an average of 26 days [Figure 2]. Only one patient (patient #9) was successfully managed without an operation and only required percutaneous drainage in addition to antibiotics. All patients received antibiotic therapy targeted to cover the known organisms causing the dSSI-MI. The median antibiotic course was 17 days. However, patient #3 remained on a total 740 days of suppressive antibiotics at the recommendation of infectious disease specialists due to a dSSI-MI in the setting of spinal hardware.
Table 3: Management and complications following deep surgical site infections with mesh involvement

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Figure 2: Negative pressure wound therapy applied to wound in two different cases

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When analyzing the ability to salvage the prosthetic mesh in dSSI-MI, mesh was left completely intact in all but three patients (patient #4, patient #5, and patient #10). Patient #4 had an anastomotic leak of their partial colectomy anastomosis. During the repair of the leak, an approximately 1 cm × 1 cm piece of unincorporated mesh was excised, while the remaining majority of the mesh was well incorporated and did not necessitate excision [Figure 3]. Patient #5 suffered a polytraumatic accident necessitating an open abdomen. During their index operation, macroporous polypropylene mesh was placed as PMA with concomitant hip fixation and gastrostomy tube placement. Postoperatively, the patient developed a gastrostomy leak that contaminated the mesh, forming a dSSI-MI. This was initially managed successfully with endoscopic purse string closure of the defect, T-fastener gastropexy, and midline wound incision and drainage, followed by NPWT and antibiotics. Nearly 2 years later, on follow-up, a small 1.5 cm × 1.5 cm piece of mesh was still unincorporated and was excised in clinic.
Figure 3: Patient #4: (a) Opening of the deep surgical site infections with mesh involvement with underlying colon anastomotic leak, (b) overlying 1 cm × 1 cm piece of unincorporated mesh, (c) granulating wound managed by negative-pressure wound therapy, and (d) final healed wound after mesh salvage

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Patient #10 developed a postoperative coloatmospheric fistula that contaminated the mesh, causing the dSSI-MI [Figure 4]. The infection was managed by operative incision and drainage with pulse lavage washout followed NPWT. On operative exploration, the fistula was explored, and an overlying 2.5 cm × 2.5 cm piece of mesh was excised to evaluate the fistula and clear the contaminated mesh and retromuscular plane. Subsequent abdominal closure consisted of reapproximation of the midline fascia with an otherwise intact retromuscular mesh. NPWT was continued for the subcutaneous wound, and the fistula was managed with local wound care. Total parenteral nutrition was used for the long-term care of the fistula, which later closed spontaneously without the need for bowel resection.
Figure 4: Patient #10: (a) Preoperative hernia, (b) Postoperative exploration revealing exposed mesh overlying a coloatmospheric fistula, (c) granulating wound managed by negative pressure wound therapy, and (d) final healing wound after mesh salvage

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Major morbidities occurred in only four patients (31%). Patient #4 and patient #8 had postoperative hemorrhage that required transfusions. Patient #5 suffered a polytraumatic accident necessitating an open abdomen. Though this was successfully closed with PMA, the patient had ongoing respiratory failure requiring a tracheostomy and further developed pneumonia, septic shock, and a pulmonary embolism.

Patient #11 developed respiratory failure and pneumoperitoneum, with exploratory laparotomy revealing gastric perforation requiring partial gastrectomy and temporary abdominal closure [Figure 5]. However, 6 days later, the posterior fascia was bridged with a biologic mesh, and the previously placed retromuscular macroporous polypropylene mesh was completely salvaged and reapproximated using a polypropylene suture in the midline, followed by anterior fascial closure. Despite this, the patient died of complications unrelated to the dSSI-MI.
Figure 5: Patient #11: (a) Postoperative exploration revealing gastric perforation and (b) underlay biologic mesh covering gastric repair with reapproximation of initial retromuscular macroporous polypropylene mesh at the midline

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Within the follow-up period, only two patients developed recurrent hernias. Patient #8 did not require further operative revision of their hernia due to the asymptomatic presentation. Patient #10 had a recurrence at the site of partial mesh debridement in addition to a chronic-draining sinus tract. The hernia was subsequently repaired with an underlay poly-4-hydroxybutyrate mesh, and the sinus tract was excised [Figure 4].


  Discussion Top


There are nearly 350,000 VHRs performed in the United States annually.[10] Over the past few decades, mesh reinforcement of hernia repairs has become the standard of care due to its reduction in hernia recurrence. Despite this, there are inherent complications associated with implantation of prosthetics into the human body. Such complications can include seroma, fistulae, mesh failure as well as mesh infection. Mesh infections have been reported to occur in approximately 0%–3% of laparoscopic repairs and 5%–10% of open repairs.[11] Given the large volume of repairs annually, even this small percentage of infection impacts large numbers of patients with significant burden on both the patient and the health care system.

Several studies have investigated predictors of mesh infection. Immunosuppressive drugs, smoking, uncontrolled diabetes, urgent repairs, and postoperative SSI have been shown to be associated with the development of mesh infections. The need for mesh excision has been linked to polytetrafluoroethylene mesh, onlay mesh position, and intraoperative enterotomy.[8],[12] Traditional management of dSSI-MI has been complete mesh excision. However, complex mesh extirpation operations place patients at risk of surgical morbidity and greatly increase the risk of future hernia recurrence. As such, there is increasing interest in the ability to salvage the mesh prosthetic in the setting of dSSI-MI.

Few groups have published their results with mesh salvage. Greenberg[7] analyzed 356 hernia repairs with composite mesh. In this series, there was a 3% infection rate, defined as fever, wound erythema, abscess, draining sinus, or exposed mesh. Though all patients initially underwent conservative management with antibiotics, incision and drainage, NPWT or debridement, 4 of the 11 infected patients (36%) went on to mesh removal.

Conservative therapy of dSSI-MI is an intuitive first step with the hope to obviate the need for mesh removal. However, patients with dSSI-MI present in a heterogeneous fashion, and a standardized approach to management would be ideal. Trunzo et al.[9] reported a unique standardized approach to managing mesh infections with successful salvage in the two reported cases. Their approach consisted of initial percutaneous aspiration of suppurative fluid for culture analysis followed by appropriate intravenous antibiotic therapy. This was followed by percutaneous drain placement in the fluid collection with subsequent gentamicin irrigation through the drain three times daily. Both patients had resolution of their suppurative infections, thus drains were removed and the mesh was salvaged.

Despite the success in the case reports of Trunzo et al., reported rates of complete mesh salvage remain low – approximately 28%–64%.[8],[12],[13] Herein, we report near-complete success in mesh salvage of dSSI-MI. Thirteen patients from two high-volume hernia centers developed dSSI-MI. As a standardized approach, conservative therapy was the first step in management (initial course of antibiotics). Complete mesh salvage was successful in all but three patients, while one patient's mesh was successfully salvaged with conservative measures alone, not requiring reoperation (patient #9). The remaining 92% of patients did require reoperation, where incision and drainage of the infection was needed in all patients. Of these, 66% required some amount of subcutaneous soft-tissue debridement. All but one of these patients (92%) were then managed with NPWT for an average of 26 days. In the three patients that necessitated partial mesh excision, two of these patients required <1% of mesh area to be excised while only 7% of mesh area was excised in the other.

The results of our series demonstrate complete salvage of mesh prosthesis in 77% of patients with dSSI-MI. In addition, we demonstrate a low hernia recurrence rate, with only one patient requiring repair for recurrence and one patient who did not. There were some notable complications in a few cases, where major morbidities occurred in 31%. Patient #11 had postoperative respiratory failure with prolonged noninvasive ventilation use, which was a major contributing factor to gastric perforation and subsequent abdominal operations that set about a cascade of complications leading to pneumonia, stroke, and eventual withdrawal of care. This patient had multiple comorbidities (coronary disease, ischemic cardiomyopathy with heart failure, chronic obstructive pulmonary disease, and atrial fibrillation). Their morbidity may have been a combination of the above comorbidities and the surgical complications, not necessarily a sole direct result of mesh infection.

With the success of salvaging synthetic and biosynthetic mesh in the study, the authors would like to highlight the following. The predominant etiology of mesh infection was gastrointestinal contamination. Thus, control of the source of the infection is paramount. With this, salvage was achievable with relatively short courses of antibiotic therapy and no long-term use of suppressive antibiotics related to dSSI-MI. To achieve this goal, it is necessary to have long-term follow-up of these patients, as there remains a risk of delayed infection in the years to follow. Nonetheless, infection of synthetic mesh can be managed without mesh explantation, and the harm of leaving synthetic mesh in an infected field may be less worrisome than previously believed. This point may argue that the subsequent management of rare dSSI-MIs in synthetic mesh may outweigh the overall cost of biologic prosthetics. Similarly, the notion that only biologic prosthetics have a place in infected fields may not be an absolute requirement.

Successful mesh salvage in this series is related to several factors. First, the retromuscular space has robust vasculature, which allows for favorable tissue incorporation of the mesh. This well-perfused abdominal wall space may also have better access to immune and tissue-repairing cells in the setting of active infection, thus potentially being more likely to better fight infection. It is possible that these factors contribute to the reduced wound infection and recurrence rates after Rives–Stoppa repairs.[14] In addition, the predominant use of macroporous, reduced density monofilament polypropylene mesh in this study was also advantageous. Studies have demonstrated favorable changes at the mesh–tissue interface, with reduced foreign body response and granulomatous bridging when utilizing macroporous polypropylene, which appears to aid in mesh integration as well as tolerate subsequent suppurative infection.[15],[16],[17] The authors caution that these results may not be applicable to other types of mesh placed in other abdominal wall planes.

There are inherent limitations of this study. First, the study population is a small group, only 13 patients, for which strong evidence may be hard to extrapolate. Consistent with many other papers, dSSI-MIs are less common than superficial SSIs; thus, it is challenging to generate large population sizes. The authors attempted to produce a large cohort study by pooling data from multiple high-volume hernia centers to accommodate this fact. Another limitation of our study is the heterogeneity of the group. To best allow for a large cohort, we included multiple types of hernia repair (parastomal and incisional) as well as PMA. There was varied use of component separation in the population as well, and there was also variation in preoperative patient characteristics. Last, the etiology of each patient's dSSI-MI was variable and could have led to various degrees of risk for failure of mesh salvage, as well as postoperative morbidities. Despite this variability, the authors were able to achieve great success in near-complete mesh salvage in all patients with a low rate of hernia recurrence and a significant long-term follow-up (median = 73 months).


  Conclusion Top


Mesh salvage without total mesh excision is achievable in patients who develop dSSI-MI. In our series, mesh salvage had a low rate of hernia recurrence and a low rate of recurrent infection with long-term follow-up, although it required meticulous postoperative management with debridement, antibiotics, and NPWT. Given the predominance of retromuscular repairs with macroporous polypropylene mesh, repair type and mesh choice may influence the ability for salvage. Caution is emphasized when attempting salvage of mesh following this treatment algorithm.

Financial support and sponsorship

This study was funded by institutional support from Oregon Health & Science University and Penn State Hershey Medical Center. Neither entity had a role in study design, data collection, analysis, or writing of the paper.

Conflicts of interest

Steve R Siegal: No disclosures.

David J Morrell: No disclosures.

Sean B Orenstein: Consulting and Honorarium from BD-Bard, Allergan-LifeCell, Intuitive, Cooper Surgical.

Eric M Pauli: Research and Honorarium from Cook Biotech, BD-Bard; Consultant for Boston Scientific Corporation, Actuated Medical; Royalties from UpToDate.



 
  References Top

1.
Kokotovic D, Bisgaard T, Helgstrand F. Long-term recurrence and complications associated with elective incisional hernia repair. JAMA 2016;316:1575-82.  Back to cited text no. 1
    
2.
Sanchez VM, Abi-Haidar YE, Itani KM. Mesh infection in ventral incisional hernia repair: Incidence, contributing factors, and treatment. Surg Infect (Larchmt) 2011;12:205-10.  Back to cited text no. 2
    
3.
Cobb WS, Carbonell AM, Kalbaugh CL, Jones Y, Lokey JS. Infection risk of open placement of intraperitoneal composite mesh. Am Surg 2009;75:762-7.  Back to cited text no. 3
    
4.
Paton BL, Novitsky YW, Zerey M, Sing RF, Kercher KW, Heniford BT. Management of infections of polytetrafluoroethylene-based mesh. Surg Infect (Larchmt) 2007;8:337-41.  Back to cited text no. 4
    
5.
Juvany M, Hoyuela C, Trias M, Carvajal F, Ardid J, Martrat A. Impact of surgical site infections on elective incisional hernia surgery: A prospective study. Surg Infect (Larchmt) 2018;19:339-44.   Back to cited text no. 5
    
6.
Birolini C, de Miranda JS, Utiyama EM, Rasslan S. A retrospective review and observations over a 16-year clinical experience on the surgical treatment of chronic mesh infection. What about replacing a synthetic mesh on the infected surgical field? Hernia 2015;19:239-46.  Back to cited text no. 6
    
7.
Greenberg JJ. Can infected composite mesh be salvaged? Hernia 2010;14:589-92.  Back to cited text no. 7
    
8.
Kao AM, Arnold MR, Augenstein VA, Heniford BT. Prevention and treatment strategies for mesh infection in abdominal wall reconstruction. Plast Reconstr Surg 2018;142:149S-55S.  Back to cited text no. 8
    
9.
Trunzo JA, Ponsky JL, Jin J, Williams CP, Rosen MJ. A novel approach for salvaging infected prosthetic mesh after ventral hernia repair. Hernia 2009;13:545-9.  Back to cited text no. 9
    
10.
Ferzoco S, Clara ES, Tang SW, Hu J, Tan WB, Shabbir A, et al. Mesh & prosthesis. Hernia 2015;19 Suppl 1:S147-56.  Back to cited text no. 10
    
11.
Petersen S, Henke G, Freitag M, Faulhaber A, Ludwig K. Deep prosthesis infection in incisional hernia repair: Predictive factors and clinical outcome. Eur J Surg 2001;167:453-7.  Back to cited text no. 11
    
12.
Bueno-Lledó J, Torregrosa-Gallud A, Sala-Hernandez A, Carbonell-Tatay F, Pastor PG, Diana SB, et al. Predictors of mesh infection and explantation after abdominal wall hernia repair. Am J Surg 2017;213:50-7.  Back to cited text no. 12
    
13.
Stremitzer S, Bachleitner-Hofmann T, Gradl B, Gruenbeck M, Bachleitner-Hofmann B, Mittlboeck M, et al. Mesh graft infection following abdominal hernia repair: Risk factor evaluation and strategies of mesh graft preservation. A retrospective analysis of 476 operations. World J Surg 2010;34:1702-9.  Back to cited text no. 13
    
14.
Iqbal CW, Pham TH, Joseph A, Mai J, Thompson GB, Sarr MG. Long-term outcome of 254 complex incisional hernia repairs using the modified Rives-Stoppa technique. World J Surg 2007;31:2398-404.  Back to cited text no. 14
    
15.
Carbonell AM, Criss CN, Cobb WS, Novitsky YW, Rosen MJ. Outcomes of synthetic mesh in contaminated ventral hernia repairs. J Am Coll Surg 2013;217:991-8.  Back to cited text no. 15
    
16.
Klinge U, Binnebösel M, Mertens PR. Are collagens the culprits in the development of incisional and inguinal hernia disease? Hernia 2006;10:472-7.  Back to cited text no. 16
    
17.
Orenstein SB, Saberski ER, Kreutzer DL, Novitsky YW. Comparative analysis of histopathologic effects of synthetic meshes based on material, weight, and pore size in mice. J Surg Res 2012;176:423-9.  Back to cited text no. 17
    


    Figures

  [Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5]
 
 
    Tables

  [Table 1], [Table 2], [Table 3]


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