Perineal Wound Post APR



Fig. 17.1
Small perineal defect after proctectomy



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Fig. 17.2
Large perineal defect after ischioanal APR


The risk of contamination of the wound by perianal or ischioanal abscesses and/or fistulae from infections or a perforated cancer is also an important factor to consider before planning the procedure. If the abscess or fistula is caused by a perforated cancer the whole affected area must be removed en bloc with the cancer to prevent seeding of cancer cells into the wound. If the abscess or fistula is not related to cancer there is still a risk of bacterial contamination of the wound with subsequent wound healing problems.

The experience of the surgical team is clearly an important factor in the management of the defect after APR. Small defects can easily be handled by colorectal surgeons but with more advanced reconstructions, including musculocutaneous flaps, the competence of a plastic surgeon may be required.



Type of Reconstruction


A variety of surgical alternatives to primary closure have been used in order to reconstruct the pelvic floor and to reduce the wound healing problems after APR. These procedures include different rotational musculocutaneous flaps, reconstruction with biological mesh, and omental pedicle flaps (omentoplasty).


Simple Closure


As mentioned above, a simple closure of the perineal wound after an APR is associated with a high risk of major wound complications. The rate may be 40% or even higher, especially in patients who have received neoadjuvant radio- or radio-chemotherapy and where the levator muscle has been more or less entirely removed. In addition, closure of skin and fat alone provides a weak pelvic floor and the patient may develop a perineal hernia as a late complication after an APR. However, simple closure may be considered in patients where an inter-sphincteric APR has been performed and the perineal defect is small; for example in mid- and upper rectal tumors, as an alternative to Hartmann’s procedure if incontinence precludes a sphincter saving procedure with a low anastomosis or in benign disease, such as Crohn’s disease, where removal of the anal canal is necessary. However, in many cases a primary simple closure is insufficient and some type of flap is often used in this situation. Indications for the use of musculocutaneous flaps include coverage of large perineal defects, vaginal reconstruction, and secondary repair of non-healing wounds.


The Rectus Abdominis Musculocutaneous Flap (Figs. 17.3 and 17.4)


Shukla et al. first published on the use of the rectus abdominis muscle flap for reconstruction of perineal wounds in three patients in 1984 [6]. Tobin and coworkers later reported on its use for vaginal and pelvic floor reconstruction and since then several series in the medical literature have demonstrated good results with relatively low morbidity associated with the use of these flaps [710].

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Fig. 17.3
VRAM flap


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Fig. 17.4
Reconstruction of the pelvic floor and perineum with VRAM flap

The rectus abdominis myocutaneous (RAM) flap may be harvested as a transverse rectus abdominis muscle flap (TRAM) or as a vertical rectus abdominis muscle flap (VRAM), depending on its variable skin paddle orientation. There are no comparative studies on the relative merits of either orientation but the VRAM flap has been used most often for reconstruction of large perineal wounds.

One of the largest series examining the VRAM flap for perineal reconstruction was published by Buchel et al. This was a retrospective review of 73 patients and reported that primary healing occurred in 85% of patients and that 95% obtained a healed perineal wound within 30 days [11]. Another study compared 19 patients with anorectal cancer treated with external beam pelvic radiation followed by APR and RAM flap reconstruction of the perineum with a control group of 59 patients treated with similar radiation doses that subsequently underwent an APR without a RAM flap during the same time period. Perineal wound complications occurred in 16% of the RAM flap patients and in 44% of the control patients, which suggests that perineal closure with a flap significantly decreases the incidence of perineal wound complications in patients undergoing external beam pelvic radiation and APR [12].

Although the RAM flap is probably the most frequently used tissue transfer to promote perineal wound healing and decrease the risk of complications, there are some concerns to be mentioned. The dissection of this flap is technically demanding and great care must be taken not to injure the inferior epigastric artery as the circulation may otherwise be compromised. The RAM flap is denervated, not contractile and thus prone to loss of volume with time. Also, donor site morbidity, such as abdominal wall weakness and an increased risk of incisional hernia, has to be considered.


The Gluteus Maximus Flap


This flap has mainly been used for pressure wound surgery but has recently been used also for reconstruction after APR for rectal cancer [13, 14]. A unilateral gluteus maximus flap is usually sufficient after ELAPE (Fig. 17.5) but with more extensive excisions, resulting in substantial loss of tissue, bilateral flaps may be necessary (Figs. 17.6 and 17.7). Most papers reporting on outcomes after gluteus maximus flap reconstruction include small numbers of patients and there is no randomized controlled comparison between the RAM and gluteus maxumus flaps. In a report by Anderin et al. 65 patients were studied after ELAPE and a one-sided musculocutaneous gluteus flap for low or locally recurrent rectal cancer. Fifty-nine had received neoadjuvant radio- or radio-chemotherapy. Twenty-seven (41.5%) patients had one or more perineal wound complications. A minor wound infection occurred in 15, while 12 had either a more severe infection with dehiscence or a pelvic abscess. The reconstruction was completely healed in 91% of the patients at 1 year [13].

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Fig. 17.5
Unilateral gluteus maximus musculocutaneous flap


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Fig. 17.6
Extensive resection of pelvic floor and perineum in a patient with perforated rectal cancer and complex ischioanal fistulae


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Fig. 17.7
Bilateral gluteus maximus musculocutaneous flaps

Advantages of the gluteus maximus flap include that it is well vascularized and innervated and does not shrink with time and that it does not cause donor site morbidity in the abdominal wall, which is especially attractive after minimally invasive surgery. The disadvantage of this flap is that is does not fill the pelvic cavity to the same degree as the RAM flap and that a combination of vaginal wall reconstruction makes the procedure more complicated.


The Gracilis Musculocutaneous Flap


Utilizing the gracilis myocutaneous flap to repair persistent perineal sinuses was described in 1975 by Bartholdson et al. [15]. This flap has mainly been used in patients with delayed healing or persistent sinuses after previous APR with primary closure, or as a primary reconstruction in patients with recurrent rectal cancer after radio-chemotherapy. Shibata and colleagues investigated perineal wound healing in patients who all received neoadjuvant radiotherapy and subsequently had an APR for recurrent rectal cancer. Sixteen patients underwent either unilateral or bilateral gracilis muscle flap closure, while 24 patients had a primary perineal closure alone. The results dramatically favored the gracilis flap closure; only 12% of the patients closed with gracilis flaps had major complications compared to 46% of the patients who underwent primary closure. In 63% of the patients closed with gracilis flaps the perineum healed without incident, but only 33% of the patients with primary closure had an uneventful recovery [16]. The drawbacks of the gracilis flap include its relatively small muscle bulk and skin fragility but despite these limitations, its role in preventing postoperative and post-irradiation perineal complications is well established [17].


Pelvic Floor Reconstruction with Biological Mesh


The different musculocutaneous flap solutions to reconstruct the pelvic floor are valuable in order to reduce complications but many colorectal surgeons have been hesitant to use flaps routinely due to the more extensive procedure, the prolongation of operation time and often limited access to plastic surgeons. Instead of reconstructing the pelvic floor by flaps it has been suggested to apply a biological mesh in the pelvic defect. This method is quick, easy to perform, and not dependent on the availability of plastic surgeons (Fig. 17.8). In addition, it seems feasible with a reasonable complication rate. In one report the use of a biological mesh also significantly reduced the risk of perineal hernia [18]. However, the number of reports is still limited and substantial, long term results from biological mesh reconstruction of the pelvic floor are lacking.

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Fig. 17.8
Reconstruction of pelvic floor with biological mesh


Omentoplasty


Bowel obstruction, due to entrapment of the small bowel in the pelvic cavity, is not infrequent after an APR. An omentoplasty filling out the pelvic cavity may reduce this cause of postoperative small bowel obstruction. Therefore, and if the patient has a large omentum, it is feasible to mobilize it from the transverse colon and from the greater curvature of the stomach and to prepare an omentoplasty which can fill out the empty pelvic cavity. Mobilization of the omentum and its placement in the pelvic cavity to prevent injury to the small bowel during postoperative pelvic irradiation is well known [19, 20]. Killeen and colleagues published a systematic review on the use of omental pedicle flaps following proctectomy. They collected data from 14 studies totaling 891 patients with a median follow-up of 13.5 months. Mean rate of primary healing with omentoplasty was 67 versus 50% with no omentoplasty. Mean time to healing in the former group was 24 versus 79 days in the latter group. The authors concluded that: “Omental mobilization and buttressing of primary perineal repair reduced perineal wound morbidity” [21].


Is There an Optimal Way to Reconstruct the Pelvic Floor and Perineum After an APR?


Butt and colleagues preformed a systematic review of ELAPE including 27 series and 963 patients. They compared the results of biomesh closures (149 patients) with musculocutaneous flap closures (201 patients) and 578 patients with primary closure. Minor and major wound complications and perineal hernias were compared. The results are shown in Table 17.1. The authors found no significant differences regarding minor or major wound complications or perineal hernias in relation to biomesh, muscle flaps, or primary closure and concluded that: “Despite several techniques currently employed for perineal construction, it remains unclear as to which is optimal” [22]. This systematic review does not include randomized controlled trials and it is highly likely that the size and nature of the defect might have affected the choice of the closure technique and resultant complication rates.


Table 17.1
Wound complications in relation to type of pelvic floor reconstruction after ELAPE
























 
Wound complication

Minor (%)

Major (%)

Perineal Hernia (%)

Biomesh

27.5

13.4

3

Muscle flap

29.4

19.4

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Oct 18, 2017 | Posted by in GASTROENTEROLOGY | Comments Off on Perineal Wound Post APR
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