Introduction

The incidence of hernias following laparotomy ranges between 9 and 50% in high-risk population patients. There also is an increased number of complex incisional hernias (IH) most of them featuring large defects (usually over 10 cm width) or loss of domain, which can lead to a profound alteration of the anatomy and function of the abdominal wall [1]. Once the linea alba has been broken, the resulting scar tissue is weaker, leading to hernia formation in specific circumstances. In recent years, the concept of abdominal wall reconstruction has been a hot topic in the field of hernia surgery. The goal of this reconstruction is a mesh-reinforced primary fascial closure, with reconstruction of the midline (linea alba) under minimal tension, resulting in minimal complications. Thus, the procedure provides the patient with both a sound and cosmetic result.

Sometimes, due to excessive tension or severe postoperative complications generated by the forced repair (intra-abdominal hypertension, abdominal compartment syndrome, or respiratory failure), large defects or loss of domain hernias cannot be closed without disconnecting some of the components of the lateral abdominal wall. These techniques take advantage of the layered anatomy of the abdominal wall, and, based on which layers are released, they can be categorized as anterior or posterior component separation.

We set out to analyze whether mesh-reinforced anterior component separation (MACS) should remain in the therapeutic arsenal and to exemplify instances in our cases when this procedure may be recommended.

Patients and Methods

Patients

We reviewed all the files of the patients with complex incisional hernias (defects larger than 10 cm width, infected abdominal wall meshes, open septic abdomen, extended infections of the abdominal wall) and ACS with and without mesh reinforcement admitted in both departments of surgery during January 2012 and December 2020 after institutional board approval. Demographic variables including patient’s age and gender were collected. Medical co-morbidities such as body mass index (BMI), chronic obstructive pulmonary disease (COPD), diabetes, smoking and alcohol habits, and ASA score were also reported. All admitted patients were investigated with standard abdominal ultrasound and native or contrast-enhanced abdomino-pelvic CT scan for size and location of the defect, muscular status, presence or absence of mesh, and infected mesh. The authors, both senior surgeons experienced in open and laparoscopic abdominal wall reconstruction, performed all the procedures.

Surgical Technique

Patients were admitted to hospital the night before surgery and received an osmotic bowel preparation and the prophylaxis of deep vein thrombosis with low molecular weight heparins according to the anesthesiologist preference. The exact size and position of the defect relative to the anatomic midline and level of the umbilicus were noted. The surgeon also had to carefully analyze the quality, position, vascularity, and mobility of the skin and muscle structures on both sides of the defect. The procedure began by elevating the skin flaps of the underlying abdominal musculature in a lateral direction towards the anterior axillary line. Next, the linea semilunaris was noted, along with the insertion of the external oblique aponeurosis (EOA). A vertically oriented incision located 2 cm laterally to Spigelian line and in the costal part of the external oblique aponeurosis, of 1 cm length, was made to identify and expand the plane beneath the EOA but superficial to the internal oblique fascia [2].

One must be careful not to dissect too deep into this layer to avoid injuring the internal oblique fascia or muscle. A deep dissection here may damage the segmental innervation of the rectus abdominis muscle or injure the Spigelian fascia, thus predisposing the patient to a Spigelian hernia. Generally, the planes are quite distinct. Once the plane is identified, the incision of the external oblique aponeurosis is extended cranially and caudally in its entire length. The dissection proceeds in this relatively avascular intermuscular plane and is continued in a lateral direction beyond the area of skin undermining to at least the level of the midaxillary line. At this point, the mobility of the innervated rectus abdominis-internal oblique abdominis-transversus abdominis muscle complex is determined.

If additional mobility of these structures on either side of the midline is desired, then the dissection in the intermuscular plane can be continued to the posterior axillary line [3]. In our experience, each ipsilateral complex can be advanced towards the midline by 4 cm in the upper abdomen, 8 cm at the waist, and 3 cm in the lower abdomen. In the rare instances in which additional advancement is needed, the rectus muscle can be elevated off of the posterior rectus sheath in its entirety. Two centimeters of additional advancement can be obtained at each level by using this maneuver, and a mesh can reinforce the reconstruction, much like in a Rives-Stoppa repair [3]. The muscles are joined together in the midline with an interrupted or continuous closure using a strong non-absorbable suture (our preference is 0 polypropylene) (Fig. 1).

Fig. 1
figure 1

Bilateral full anterior component separation

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The skin flaps are then also advanced to the midline and approximated in a layered closure. Four suction drains are used routinely, and these are positioned in the plane between the oblique muscles and beneath the skin flaps on each side of the midline. They are brought out through separate stab incisions in the pubic area, lateral abdomen, or both. They are maintained until the drainage decreases to less than 30 cc per 24 h, which is usually at an average of 7 days.

When the peritoneal sac develops much further towards the lateral, for its release, the subcutaneous dissection reaches the vicinity of the linea semilunaris, or even exceeds it (Fig. 2, 3).

Fig.2
figure 2

Peritoneal sac developed further to the sides

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Fig.3
figure 3

Peritoneal sac developed mainly to the left side

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As an exception, if the length of the parietal defect is limited (supraumbilical, mesogastric, infraumbilical), the incision may be reduced, if it largely exceeds the defect [4]. If recreating the linea alba is possible after the unilateral practice of the EOA incision, contralateral anterior component release is not necessary (Fig. 4) [5]. The prosthesis is fixed in the onlay position and must cover the area of the component separation. To do this, the prosthesis is attached to the lateral edge of the EOA (Fig. 5).

Fig. 4
figure 4

Unilateral limited incision of external oblique fascia (on the right side)

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Fig. 5
figure 5

Unilateral limited incision of external oblique fascia (on the left side – mesh in place)

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Results

During the reference interval, the ACS procedure was used in 66 consecutive patients (41 men) with a mean age of 68.7 ± 8.5 years. All patients presented unique or associated comorbidities; obesity with a BMI over 32 kg/m2 was reported in 58 patients, diabetes in 38 patients, and COPD in 18 patients. Our indications included:

  1. 1.

    recurrent incisional hernias with chronic infected mesh removal after incisional hernia repair in 28 patients. The onset of mesh infection was over 3 months after primary repair (mean time-lapse 19.8 months, range 3 months–25 years);

  2. 2.

    open septic abdomen treated with negative-pressure wound therapy in 8 patients, open septic abdomen treated with Bogota bag in 10 patients. The main causes for open abdomen were anastomotic fistulas after colorectal surgery in 9 patients, after gastro-intestinal surgery in 3 patients, advanced primary peritonitis in 4 patients, and necrotic pancreatitis in the rest;

  3. 3.

    abdominal primary or secondary tumor resection in 2 patients; and

  4. 4.

    abdominal wall resection for multiple septic granulomas in 13 patients.

Of these, 29 patients (47%) presented postoperative complications. They were represented by skin necrosis in 13 patients, hematoma in 15 patients, and a burst abdomen in 1 patient. The mean hospital stay was 16.7 days (9–56 days); all wounds healed between 48 and 72 days (57.4 days). Recurrence was recorded in 18 patients (29%), all within the first year after the procedure. Of them, seven recurrences were noted in patients with postoperative hematoma, 1 after the burst abdomen, and the rest of them in patients without postoperative complications but with associated co-morbidities (5 in patients with BMI larger than 30 kg/m2, 3 in diabetic patients, and 2 in COPD patients). All recurrences were clinically and CT scan documented. All recurrent defects were located in the midline and were probably a healing or technical defect. There was no defect recorded lateral to Spiegel line. Only two of this patients were re-operated; defects smaller than 6 cm were primary closed and the suture was reinforced with a large sheet of light monofilament polypropylene 30 × 30 cm secured with cyanoacrylate blue.

  1. 5.

    large incisional hernias with clean condition. We used MACS in five patient cases in which an extended subcutaneous supra-aponeurotic space was developed after sac dissection. In three patients, we practiced bilateral complete anterior component separation, and for the other 2 cases, unilateral limited anterior component separation. Patients were discharged after an average of 12.6 days (between 7 and 16 days). There were 2 patients with wound complications, represented by seroma, wound limited breakdown, and consecutive superficial infection. Wound healing was obtained after 58 and 94 days, respectively. Recurrence was seen in none of the five patients during postoperative follow-up sessions after at least one year.

Discussion

The closure of the abdominal wall defects using anterior components separation (ACS) was first reported by Albanese in the 50 s, but Ramirez et al. re-described and popularized it in 1990 [6, 7]. This technique is unique in that the functional transfer of the abdominal musculature provides stable and dynamic support to the abdominal wall, without the need for musculofascial flaps.

For 3 decades, ACS was the corner stone of abdominal wall reconstruction in patients with large incisional hernias. Mesh reinforcement, as on lay or underlay, was an important adjunct for improving outcomes due to its low recurrence rate. Many surgeons were reluctant to use it due to the logical sequelae of large myofascial and subcutaneous flap elevation. Some common complications are possible and these include seroma, hematoma, infection, skin edge necrosis, wound breakdown, and hernia recurrence [5, 8].

Although it has entered clinical use only in a few surgical services, in complex ventral hernia repairs, subcutaneous perfusion mapping with indocyanine green angiography in infrared light offers high sensitivity and facilitates the identification of ischemic tissues, thereby reducing the incidence of delayed wound healing and the risk of surgical site infection. This technique has the potential to reduce costs and improve patients’ quality of life by reducing the likelihood of wound complications and reoperation [9].

The complications resulting from ACS can be reduced using minimally invasive ACS, such as perforator sparing or endoscopic techniques [10, 11]. However, it should be noted that, in these procedures, the prosthesis will be placed in the sublay or underlay position, which increases the duration, complexity, and costs of the operation. Furthermore, in these technical variants, the prosthesis will not protect the weak area resulting from the EOA incision, increasing the risk of a lateral bulge or lateral abdominal wall hernia.

With regard to posterior component separation (PCS) and PCS-TAR, we believe it offers superior results to those otherwise obtained using MACS [5]. Most recent innovations have been achieved through the use of the minimally invasive approaches of endoscopic TAR (eTEP TAR) and robot-assisted TAR (rTAR) [8].

The information found in the literature related to incisional hernia is often contradictory. On the one hand, the onlay procedure retains its purpose and role [12, 13]; on the other hand, it is stated that MACS should be no longer performed because it has a high complication rate [14, 15]. Moreover, there are authors who view MACS and PCS-TAR as having comparable outcomes in complex abdominal wall reconstruction of midline ventral incisional hernias [10, 16].

To date, no comparative clinical or animal studies on the efficacy of various component techniques have been published. This is not surprising given that most surgeons prefer one technique over the other and the likelihood of a well-designed prospective randomized trial remains low [17, 18].

A challenging issue, for both patient and surgeon, is the recurrence after ACS without mesh because abdominal wall reconstruction is difficult to perform even for patients with small defects. Posterior component separation via TAR being it open or endoscopic is prohibitive in the first six months because of the important abdominal wall destabilization. After this period, the procedure can be considered with an in-lay mesh reinforcement but remains reserved only for specialized centers or dedicated surgeons with abdominal wall surgery expertize. On-lay mesh reinforcement could be a valid option in patients with small defects but the re-recurrence rate is not yet estimated.

For large midline hernia defects, if the release of the hernia sac requires extensive subcutaneous dissection, we consider the incision of the EOA to be a useful and acceptable option to close the midline. The morbidity of the operation does not derive from the EOA incision, but from the subcutaneous dissection, which has already been completed. If the dissection performed can allow for the installation of a sufficiently large mesh to reinforce the abdominal wall, we can proceed to practice MACS. In such situations, PSC-TAR or other technical procedures can be utilized to close the linea alba, although the morbidity following wide subcutaneous dissection will be added to that of wide retromuscular dissection.

MACS is not a complicated procedure compared to other component separations. For surgeons who frequently use onlay mesh placement, with the addition of EOA release, the proportion of cases in which it will be possible to close the medial defect will be higher than after the use of the classic relaxation incisions made in the anterior sheath of the rectus abdominis muscle.

We strongly believe that any hernia surgeon should be well versed in several techniques so they can offer the best technical option to patients with large incisional hernias.

Conclusion

Anterior component separation is still a valid option for reconstruction of the septic abdominal wall despite its high rate of wound complications. If a wide subcutaneous dissection is required, MACS remains a valid alternative in abdominal wall reconstruction in certain cases, but it is an exception due to the benefits of newly introduced posterior component separation via TAR.