Central perforated VRAM flap and neurostimulated levator augmentation for functional and aesthetical reconstruction after abdominoperineal excision in cancer

1. Introduction

Reconstruction of perianal soft tissue and fecal continence is challenging after abdominoperineal excision (APE) in advanced anal or rectal carcinoma, anorectal traumata or radiation damage. Intrapelvine dead space, microbial colonization, poor vascularity of surrounding tissue due to neoadjuvant irradiation and high tension sutures in primary closure, frequently lead to a restricted healing process [1, 2, 3, 4].

Plastic procedures for soft tissue coverage and packing extensive pelvic defects prevent wound breakdown as well as abscess formation and reduce hospitalisation perioperatively [1, 3, 5, 2]. Especially pedicled myocutaneus flaps supply safe coverage, providing bulky, well-vascularized soft tissue to fill dead space.

Beside pedicled myocutaneous M. gracilis flap, myocutaneous biceps femoris flap, the omentum major flap and the myocutaneous M. gluteus inferior rotation flap, the distal pedicled vertical rectus abdominis myocutaneous flap (VRAM) is a reliable and versatile reconstructive alternative [1, 6, 7, 8]. First reported by Mathes and Bostwick 1977 [9], Shukla introduced the indication for perineal reconstruction in 1984 [10]. Since then the VRAM gained importance [9, 10]. Next to large radius of movement of the robust and reliable pedicle, the well-vascularized bulky muscle and low complication rates favor the VRAM to other flaps [6, 11]. Compared to primary wound closure, significantly fewer complications like perianal abscesses or wound healing disorders were seen after reconstruction using VRAM [3, 5, 12, 13, 14, 15, 16].

APE will result in loss of natural defecation via the anorectal system. An abdominal terminating stoma is an easy manageable option but impairs patients body appearance and social behavior [17]. Therefore, a perineal pull-through descendostoma may improve life quality. Unfortunately, APE brings loss of intern and extern anal sphincter and the puborectal loop as well. Preservation of continence is therefore a complex task. The literature has outlined the importance of the puborectal sling in maintaining fecal continence. As part of the levator ani, it determines the anorectal angle and influences essential outlet resistance. Failure results in complete fecal incontinence [17] (Fig. 1). Additionally, preoperative thickness of puborectal sling can predict functional outcome after anterior rectum excision [18].

Functional reconstruction of the levator sling can be achieved by augmentation with an externally neurostimulated, dynamic graciloplasty. The dynamic graciloplasty is a well-known procedure for reconstruction of the anal sphincter in severe fecal incontinence [19, 20]. For reconstruction of the anorectal sling by dynamic graciloplasty, the proximal pedicled gracilis muscle is translocated in the pelvic cavity, wrapped around the neorectum and augmented to the levator ani muscle. A remote controlled contraction is provided by a subcutaneous placed neurostimulator. The generated contraction of the reorientated gracilis sling leads to a reestablished anorectal angle [21].

Achieving perineal coverage and preserving continence using a pedicled VRAM including a pull-through descendostoma and augmenting levator ani sling with a neurostimulated dynamic graciloplasty could have a major impact on quality of life in patients recovering of APE.

Hypothesis: A surgical method combining a VRAM with central pull-through perineostoma and additional electroneuro-stimulated, dynamic graciloplasty is a safe and feasible method for functional and aesthetic perineal and perianal reconstruction.

Aims: How safe is this new method concerning complications, functional continence measures and postoperative quality of life? Is there a difference between simultaneous or a two-stage reconstruction?

2. Methods

Between 2009 and 2019, all medical records of patients who received a perineal soft tissue reconstruction with a VRAM and a pull-through perineostoma after APE were analyzed retrospectively. Additionally, patients who received subsequent dynamic graciloplasty restoring fecal continence were included. Further patient selection was performed according to the following:

Inclusion criteria were: a. perineal defect after abdominoperineal rectum excision; b. age of the patient $>$ 18; and c. complete medical records. Exclusion criteria were: a. dynamic graciloplasty only; b. incomplete records; c. non-compliance; d. any acute or chronic conditions that would limit the ability of the patient to participate in the study; and e. refusal to give informed consent.

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Figure 1.

Puborectal sling as part of the levator ani determining the anorectal sling.

All surgical procedures were performed in collaboration of the Department of General, Visceral, Transplant, Vascular and Pediatric Surgery and the Department of Trauma-, Hand-, Plastic- and Reconstructive Surgery of the University Hospital of Wurzburg. The institutional review board approved the study. All patients gave their informed consent.

2.1 Surgical technique

After abdominoperineal excision transpelvine transposition of a pedicled myocutaneous VRAM to cover the perineal defect was performed (Fig. 2). Surgical technique for harvesting the inferior pedicled myocutaneous VRAM has been described in great detail in previous publications [2, 9, 10]. After elevating the flap from its origin, the procedure was modified by meticulously dissecting the muscular pedicle like a perforator flap to create an opening to pass the descending colon centrally through the VRAM. The dissection started with the pedicle (A. epigastrica inf.) entering the muscle following the pedicle aiming to the skin. Signs of macroscopic bleeding and direct visualization of the vascular pedicle confirmed viability of the flap intraoperatively. After the dissection of the pedicle and determination of the position of the neostoma, an opening through muscle to skin under protection of the perforators was performed (Fig. 3).

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Figure 2.

Sagital view of the transposed pedicled VRAM to cover the perineal defect.

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Figure 3.

Sagital view of pull-through descending colon to form the artificial perineostoma.

Then, the pedicled flap was pulled through the pelvic cavity and rotated 180 ∘ to use the muscle to seal the cavity and cover the perineal defect.

Afterwards, the pull through of the descending colon war performed and placed in the artificial opening to form the perineostoma. To protect the perineostoma during healing time a protective ileostoma was applied. Easy-flow drainages were placed at flap site, and one redon drainage was used at the donor site.

To reconstruct fecal continence a graciloplasty to augment the levator ani sling was performed. Therefore, the gracilis muscle was raised pedicled proximally and pulled through the foramen obturatorium. The gracilis muscle sling was placed in a u-shaped fashion on the levator ani sling and fixed to the os pubis (Fig. 4). To reconstruct the anorectal angle the gracilis muscle was neurostimulated by a stimulation device (Model 4350-45, Medtronic, Minneapolis, MN, USA) placed subcutaneously at the lower abdomen and connected to the muscle close to its pubic insertion.

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Figure 4.

Axial view of the graciloplasty to form and augment the levator ani sling for restoration of the anorectal angle.

3. Results

The retrospective analysis of all medical records during 2009–2019 resulted in a total of 14 patients that were included in the study. The median age was 57 years, ranging from 47 to 70 years. The cohort consisted of 6 female and 8 male patients. All of these patients suffered of anal ( n = 4) or rectal carcinoma ( n = 10) of different stages and received neoadjuvant chemoradiation. All patients received an APE and a perineal reconstruction with a pedicled VRAM and pull-through perineostoma simultaneously (Fig. 5). Of these 14 patients, 4 were treated by the before mentioned procedure only without a graciloplasty. In two of these patients the levator could be preserved, the other two refused gracilopasty after the first step. The other 10 patients received an APE, the VRAM reconstruction including the perineostoma and a neurostimulated graciloplasty. Three of the 10 patients received the neurostimulated graciloplasty simultaneously in a single-stage procedure. 7 of the 10 patients received the APE and the VRAM concurrently, followed by the neurostimulated graciloplasty in a second step (3–11 month later, in median 8 month later). All patients were resected R0. Primary wound closure was achieved at all sites and cases.

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Figure 5.

Perineal VRAM reconstruction including perineostoma 2 weeks postoperatively.

The average total procedure time was 471minutes (ranging 403–509 min) in the single – stage group and 306 minutes (ranging 212–452 min) for first step and 159 minutes (ranging 123–186) for second step in the two-stage group.

Protection of the perineostoma during initial healing period was achieved by a deviating stoma.

Early complications such as wound breakdown during the first 14 days appeared in 3 cases at perineal VRAM reconstruction and in 2 cases at abdominal donor site. The abdominal wound breakdowns required additional surgical intervention. Early postoperative infection occurred at donor site after graciloplasty in 3 patients that were treated with antibiotics. One VRAM suffered from clinical signs of venous stasis initially which was solved with leeches. Furthermore, partial necrosis of the VRAM occurred in 3 cases as well as 1 complete flap necrosis. The complete flap necrosis required additional surgical intervention with removal of the necrotic flap and wound closure by a local rotation flap. The partial flap necrosis were treated by secondary healing. In one case, necrosis of the perineostoma occurred and was treated by surgical revision (Table 1).

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Figure 6.

Intrapelvine pedicled VRAM with perineostoma 3 month postoperatively.

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Figure 7.

Intrapelvine gracilis sling augmenting the levator ani 3 month postoperatively.

Another patient exhibited an infection of the neurostimulator that was treated by surgical revision. One patient sustained a thrombosis of the donor site leg which was treated successfully by anticoagulation therapy.

Postoperative patients stayed in hospital after APE, VRAM and perineostomy for 27 days on average (ranging 13–51 days). Patients who received a single-stage procedure including the graciloplasty were hospitalized postoperatively for 22 days on average (ranging 13–36 days). Patients with a two-stage procedure stayed 28 days on average (raging 18–51 days) after the first session and 11 days (ranging 8–11) after second session.

Regarding long-term complications, 4 patients suffered from perineostoma stenosis. In one case, a stenosis was solved by resection of the necrotic VRAM partially including the perineostoma and secondary coverage by M. gluteus inf. flap in combination with reinsertion of the perineostoma 4 month postoperatively. Two other cases were treated successfully by endoscopic dilatation. The fourth patient showed a progression of his rectal cancer and needed an extensive resection with a terminal colostoma. One patient suffered of a prolapse of the perineostoma, which was treated by resection and new insertion.

Comparing early complications of the single and two-stage group, early complications appeared mostly in the two-stage group after first step procedure (APE + VRAM) (Table 1).

At 3 months follow up computer tomography showed the VRAM and gracilis-sling at the requested position analogue to the physiological puborectalis muscle (Figs 6 and 7). The dynamic pelvicography shows a restored anorectal angle during stimulator activity (Fig. 8).

Functional results of 7 patients were available as depicted in Table 2. Measurement of constipation by CCCS showed low scores postoperatively. Measurement of incontinence by CCIS and FISI showed mean scores of 12.3 ( ± 1.8) and 36.3 ( ± 4.9) points, respectively, implying acceptable postoperative function. The mean time interval without loss of stool (T continence) was 46.6 ( ± 29.1) hours. Two patients took antidiarrheal medication if needed.

Assessment of quality of life by EQ-D5 questionnaire and Fecal Incontinence Quality of Life (FIQL) were available in 6 patients. Results are depicted in Table 3. General quality of life and subjective status of health assessed in all patients were good after perineal reconstruction and dynamic graciloplasty. Comparison of quality of life related to fecal incontinence was restricted by absence of preoperative data but good by tendency.

All but one patient stated they would undergo VRAM plus dynamic graciloplasty again and prefer a single stage procedure.

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Figure 8.

Pelvicography 3 months postoperatively.

The VRAM plays a significant part in the reconstruction of extensive perineal or perianal defects as well as covering defects up to the sacral region, the vagina [11, 22, 23]. Modifications such as central implementation of a perineostoma as well as combining a functional restoration of fecal continence through dynamic graciloplasty provid the opportunity to mirror a natural and healthy situation. Despite dissection of the pedicle and formation of the neostoma under direct visualization, central dissection of the flap inherits the risk of compromising perfusion. Our data show minor perianal complications such as wound break down, wound infections or partial flap necrosis in 43% of tumor patients. None of these patients needed further surgical intervention. This matches rates for minor complications reported in Spasojevic et al. with rates around 10.5–42.9% [15]. One complete flap loss parallels literature with a rate of 7.1% [3, 15, 24]. The modification does not seem to increase complication rate. This approach results in a more natural and aesthetic appearance for the patient. If the surgeon has the appropriate microsurgical experience, dissection through the rectus abdominis muscle does not risk flap perfusion.

Two patients (14.3%) presented with abdominal wound break down needing surgical revision. No increased complications at area of abdominal elevation were seen compared to isolated laparotomy during the abdominoperineal resection, which is in concordance with literature [3, 5, 12].

Overall complication rates are comparable to oncologic cohorts with neoadjuvant chemoradiation and expectable restricted soft tissue conditions. Wound healing disorders, revision surgery, longer hospitalization and lower life quality is known to be predictive in irradiated patients [4, 25, 26].

Our data show little difference between simultaneous and two-stage approach regarding complication rates. Additionally, we support the idea of a single stage approach, as we could not see severe drawbacks in this group. Overall time of surgery in single stage group (ARE + VRAM + graciloplasty) extended time of first stage (APE + VRAM) by 165 min but spared a second procedure with all risks and expenditure. Nevertheless, overall time of hospitalization was reduced considerably.

Besides the possibility of tumor recurrence, postoperative rate of fecal insufficiency causes most stress in patients. Functional surveys 3 months postoperatively after neuro-stimulated graciloplasty showed the requested anorectal angle and restricted fecal passage in pelvicography. Additionally, disease specific quality of life surveys shows satisfying urgency control and continence episodes up to 72 hours in most patients. However, interpretations are restricted by the absence of preoperative incontinence and associated data. Generic quality of life is preserved. All but one patient would undergo the procedure again. All patients would prefer the single stage approach.

A weak point of the study is limited amount of patients and the fact that the groups were not matched. Therefore, the impact on validity is restricted as no statistical measurement could be performed. The results are retrospective and not blinded. There is the possibility of a bias in patient selection.

Our study shows an additional opportunity to reconstruct continence after loss of sphincter function and consecutive fecal insufficiency requiring two highly specialized teams as collaborating partners (visceral and plastic surgery) to achieve optimal results.