Multivisceral pelvic exenteration often represents the only option for sustainable treatment of patients with primary or recurrent advanced pelvic malignancy 12. Musculocutaneous flaps are commonly used to fill the resulting intra-abdominal void created by the exenteration and to reconstruct the pelvic floor and perineum. VRAM flaps weaken the abdominal wall, which can be reinforced using mesh 34. Due to potential contamination of the surgical field, there has been considerable controversy regarding implantation of foreign material, primarily, in the abdominal wall 5.

The aim of the present study was to ascertain whether primary reconstruction of the abdominal wall with mesh after pelvic exenteration and harvesting of VRAM flaps is associated with increased risk of complications. An additional objective was to determine whether patient demographics or treatment procedures could identify specific indications for use of abdominal wall reinforcement in this setting.

We conducted an observational retrospective cohort study of all patients at our hospital who underwent extended perineal resection for pelvic malignancy and received a VRAM flap for perineal reconstruction. Prior to the surgery, the patients were given radiotherapy (50–60 Gy) in the lower pelvis and perineum and concomitant chemotherapy. Surgery was planned five weeks later and was performed on average 41 days ( range 38-46 d ) after neoadjuvant treatment. A total of 58 patients were operated between January 2004 and January 2014. No reinforcement of the flap donor site was done during the period 2004–2009 (32 patients), whereas from 2009 to 2014 the abdominal wall was reinforced using synthetic mesh (26 patients).

All in- and out-patient medical records were systematically reviewed, and data on the two

groups (i.e., those with and those without mesh reinforcement) were analyzed. Clinical data on patient demographic characteristics, comorbidity status, and tumor histology are shown in Table 1. There were fewer female patients in the group without mesh reinforcement. The patients with mesh were significantly younger, and one fourth of them were receiving immunosuppressive therapy other than the oncological chemotherapy. There were no differences in BMI or comorbidity between the two groups. Tumors were either adenocarcinomas of the rectum or anal squamous cell carcinomas.

Continuous data are presented as median (range). Intergroup comparison was carried out using Fisher’s exact probability test and Levene’s test for equality of variances. Statistical significance was set at a level of 5%. Statistical analyses were conducted using SPSS software (SPSS Inc., Chicago, IL, USA).

Table 2 lists the types of surgical procedure used for tumor removal and the preoperative treatment given. The majority of patients had received radiation at the recipient site. There were no significant differences between the patients with and those without abdominal wall reinforcement in terms of the defects created after the various oncological procedures. There were more patients with sacral resection in the groupwithout mesh reinforcement, whereas there were more vaginal resections in the group with reinforcement.

Procedures performed without mesh reinforcement led to significantly greater blood loss. However, there was no difference in the duration of the surgical procedures between the two groups, but significantly more patients underwent a two-session procedure in the mesh group (31 versus 6%). Differences between the groups with regard to the number of days of hospital stay were not statistically significant (Table 3).

Table 4 shows early and late morbidity after VRAM flap and abdominal wall reconstruction. The procedures were associated with considerable morbidity, although there was no statistically significant difference in overall complication rate between the two groups.

Patient demographics were not associated with the frequency of complications neither at the donor nor the recipient site. (Levene´s test). Larger numbers of patients with mesh reinforcement required ICU care.

Morbidity at the recipient site is outlined in Table 5. Wound infection/dehiscence at this site was the most common early complication. Total flap necrosis necessitating re-operation occurred in two patients in the group without mesh and in five patients in the group with mesh. Late complications observed at follow-up included delayed wound healing and discrepancy in flap size. There was no statistically significant difference in recipient-site morbidity between the two groups.

Donor-site complications were wound infection with or without dehiscence (early), and hernia or bulge (late), as shown in Table 6. One patient without mesh reinforcement was returned to the operating room due to wound infection, and another was re-operated for an incarcerated hernia at the stoma. One patient with mesh required secondary suture of the abdominal incision. The bulge rate was significantly higher in patients without mesh. No mesh had to be removed due to any complication.

We studied patients with tumors of the rectum and anus to investigate the use of pedicled VRAM flaps for reconstruction of pelvic floor defects and implantation of non-absorbable mesh for reinforcement of the abdominal wall. The data we obtained show that harvest of rectus abdominis muscle was not associated with undue major morbidity at either the donor or the recipient site. The use of synthetic mesh in the primary closure of the abdominal wall after colorectal procedures did not increase the incidence of wound infection and in

stead led to fewer hernias and better body contour in the long run. However, our results did not identify a specific group of patients that would probably benefit from simultaneous perineal and abdominal wall reconstruction.

VRAM flaps have been used in association with removal of advanced pelvic tumors involving wide perineal resection 89. The resulting large pelvic and perineal defects create wounds in irradiated, poorly vascularized tissue that are prone to infection and delayed healing 3101112. As shown in earlier investigations 91314, a VRAM flap introduces well-vascularized tissue that fills the pelvic defect, providing structural support for internal organs and interposing healthy skin in the perineal wound. Maricevich et al. 15 demonstrated that VRAM flaps represent a reliable option for reconstruction of the large-volume defects that arise after sacrectomies. In the series evaluated by those authors, skin dehiscence was 25% at the recipient site and 5.4% at the donor site, whereas wound infection was 9.6% and 8.1%, respectively. Preoperative chemotherapy and radiotherapy did not affect early morbidity. Sunesen et al. 13 observed no major perineal wound complications and no major wound infections when using VRAM flaps after pelvic salvage surgery. Nevertheless, in contemporary studies of large cohorts 1016, VRAM flaps were found to be associated with 11% major perineal wound dehiscence requiring secondary sutures or vacuum dressings. Also, in yet another study 17, it was demonstrated that wound healing was adversely affected by overweight, diabetes, and malignancy, but not by previous irradiation of the recipient site.

The above-mentioned findings are corroborated by our results showing a high frequency of wound infection at the recipient site in the early post-operative period and also delayed perineal healing. We observed major morbidity requiring re-operation in 12% of all cases. Early complications were apparently associated with flap ischemia or necrosis, indicating that irradiation was not a significant contributing factor. We did not find any correlations between complications and BMI, comorbidity, or smoking, possibly due to the small numbers of patients in the studied cohort.

The risk of morbidity at the donor site has been a drawback of the use of VRAM flaps. Improper healing and loss of muscle tissue can potentially cause abdominal wall incompetence or hernia, and several studies have noted fascia wall dehiscence and herniation ranging from 9% to 17% 681318. However, another investigation revealed no increase in complications related to the VRAM flap donor site 3.

In the present study, we observed a considerable number of wound infections at the VRAM flap donor site in patients without abdominal wall reconstruction, although the majority of those infections were minor and did not require re-intervention. This group also had longer operation time and increased peri-operative bleeding, which might account for a higher risk of contamination. Patients who underwent reconstruction with mesh received an extra dose of antibiotics prior to mesh implantation, and treatment was continued with a broader spectrum prophylactic regimen several days peri-operatively, which might have affected the bacterial flora at the site of the wound. A significantly higher number of patients with mesh reinforcement had undergone two-session procedures, but no adverse effects on wound healing were apparent in this group compared to the early morbidity noted in the group without reconstruction. Herniation and bulging accounted for almost half of the late complications in the patients without abdominal wall reconstruction, which is higher than the level reported by other investigators 1017. No late morbidity due to incarceration was observed, and the abdominal brace that was provided was not used continuously by many of the patients.

Primary reinforcement of the abdominal wall with prosthetic mesh was introduced to circumvent abdominal wall deficiency during the later part of the present study period. In colorectal surgery, primary closure of the abdominal incision using non-absorbable mesh is still controversial due to potential contamination of the surgical field and an associated increase in the risk of infection 319. To our knowledge this is the first report comparing specifically the use of synthetic mesh for primary abdominal wall reinforcement after harvesting of the rectus muscle in pelvic cancer procedures. Although mesh reinforcement did not prolong operating time, significantly more patients with implanted mesh had two-session procedures and had to remain intubated in the ICU overnight. Furthermore, three patients with mesh were kept in the ICU for hemodynamic stabilization. Also, hospital stay was longer in patients with mesh than in those without such reinforcement, although this difference was not statistically significant.The patients were fully mobilized and could sit uninhibited before discharge which resulted in rather long hospital stay periods. Our data suggest that non-absorbable mesh can be applied without increasing wound infection or dehiscence. Even though the patients with mesh had undergone neoadjuvant chemoradiotherapy, and 27% of them were receiving systemic immunosuppressive therapy, there was no apparent abscess formation, and it was not necessary to explant any of the meshes. Long-term outcomes included significantly better body contour, as indicated by the absence of wall deficiency.

In a recent review of materials used for abdominal wall reinforcement, Lee et al. 20 noted that a wound infection rate of 6.4% and a hernia rate of 3.2% were associated with synthetic non-absorbable prosthetics in clean-contaminated cases, which confirms the present results.

We did not find any correlation between the rate of complications and comorbid conditions in our patients.

The present study had several limitations, one of which was the retrospective design with a relatively small number of patients. Also, there is an inherent bias in the outcomes, because the two groups of patients underwent surgery at different times with variable oncological procedures. Furthermore, the patients were not randomly assigned to receiving a VRAM flap or having abdominal wall reinforcement, and we did not evaluate outcomes with regard to restriction of abdominal wall strength.

In conclusion, primary implantation of synthetic mesh appeared to be safe even in the current potentially contaminated field. Nevertheless, it should be noted that implantation of mesh led to operative procedures extending over two days for one third of the current patients, and the patients without abdominal wall reinforcement did not use an abdominal brace. Accordingly, further studies should be performed that include evaluation of abdominal wall functionality and measurement of quality of life in order to identify patients that can clearly benefit from abdominal wall reinforcement after harvesting of VRAM flaps.

The authors wish to thank Mr Lars Wallgren, MSc, Lecturer, Dept of Statistics, Lund University, Lund, Sweden, for his contribution in the statistical analysis and Ms Monica Keidser ,Dept of Clinical Science, Lund university, Lund, Sweden for excellent secretarial assistance.