Minimally Invasive Component Separation for the Repair of Large Abdominal Wall Defects

Fig. 14.1

(a) Normal anatomy of the abdominal wall. (b) Section of the external oblique 1–2 cm lateral to the semilunaris line. (c) Dissection of the external oblique muscle from the internal oblique in order to allow the muscle complex formed by the rectus–internal oblique—transversus abdominis to slide towards the abdominal midline

Fig. 14.2

Section of the posterior rectus sheath to allow extra mobilization of the rectus complex

The anterior component separation technique , besides the capability of closure for large abdominal defects without using prosthetic material, reconstructs a functional abdominal wall. This is impossible to achieve in the classical methods of mesh bridging without midline approximation.

Since the original technique of anterior component separation was described, many variations have been made, mostly to avoid the morbidity associated with extensive cutaneous flaps. Even in the open technique perforating vessels must be preserved in order to avoid skin ischemia, significantly lowering the morbidity of the procedure [27, 28].

Open anterior component separation is still an important armament for the abdominal wall surgeon in difficult cases, moreover for those defects that reach the lateral abdominal wall. Nevertheless the significant associated skin related morbidity, even with perforator preservator, must be taken into consideration.

Minimally Invasive Anterior Component Separation Technique

Introduction

When it comes to defining minimally invasive anterior component separation, a wide range of different techniques appears in the literature instead of a single well-defined approach. This concept can be divided into two large subgroups with a fundamental distinguishing characteristic: the use or not of video-assisted equipment to perform fascial dissection. In order to understand the different techniques under the same general name we have summarized the surgical approaches and descriptions based on these two subgroups.

Minimally Invasive Component Separation Technique Without the Use of Video-Assisted Equipment

To avoid the large skin flaps and injury to perforating vessels, smaller incisions can achieve the same final goal on the release of the external oblique fascia. Dumanian et al. use a transverse subcostal incision to gain access to the external oblique fascia and perform the component separation under direct vision and their release takes about 15–20 min [15]. Buttler and Campbell also published their data on approaching the external oblique fascia through a tunnel created from the midline incision, avoiding two additional lateral incisions [29]. In this study, comparison to other methods is difficult, given that no description of operative times for the component separation alone, was reported.

It is necessary to have in mind that all these approaches are in fact less invasive, with lower complication rates than classical open techniques but they do not use video-assisted equipment and therefore need bigger incisions.

Video-Assisted Anterior Component Separation Technique

Many different names are used under the same basic technical principles as endoscopic component separation, video-assisted component separation, and laparoscopic component separation. Laparoscopy derives from the Greek words lapara, which means “the soft parts of the body between the rib margins and hips” or “loin,” and skopeo, which means “to see or view or examine” [30]. By analogy with laparotomy it generally implies the entrance in the abdominal cavity in order to examine or make a procedure inside the abdomen, which actually does not happen in the anterior component separation technique although the same surgical material is used. Endoscopy is derived from the Greek word endon “within” and skopeo “examine” [30]. Usually procedures take place through the endoscope itself with imaging guidance through imaging projection on a screen and actually some minimal invasive component separation are done by this method. Video-assisted surgery is a procedure that is aided by the use of a video camera that captures and projects the image on a screen. It is our opinion that despite the points of truth in every designation, the one that most accurately corresponds to anterior component separation is video-assisted (although it uses laparoscopic material) and will be described later in this chapter.

Comparing Results from Different Anterior Component Separation Techniques

When comparing anterior component separation techniques there appears to be a general consensus regarding the beneficial effects of minimally invasive techniques compared to open anterior component separation, specially regarding post-operative pain and skin complications [31–35]. However, one of the main questions posed is if minimally invasive anterior component separation technique can offer the same rectus advancement as the open technique. Knowing that the release of the external oblique fascia alone does not promote complete advancement, it is mandatory to add the dissection of the external from the internal oblique muscle, moving the external oblique as laterally as possible, usually to the posterior axillary line. Rosen et al. have used a porcine model and demonstrated an average of 86% of the myofascial advancement with video-assisted component separation compared with a formal open release [36]. To our knowledge no similar comparative study exists between different minimally invasive techniques.

Regarding comparison of operative times, rectus complex advancement, complications, and costs between the different minimally invasive procedures studies are definitely needed. One of the problems pointed out in the video-assisted approaches are the costs and extra material involved when compared to the minimally invasive procedures without video-assistance. Rosen et al. reported that the total direct costs associated with video-assisted and open anterior component separation technique were actually similar because other issues are more important to global cost [37]. In fact, these patients usually represent extremes instead of daily realities and many other factors account for global cost and success such as the use of synthetic or biological meshes, post-operative complications, and hospital length of stay.

Pre-operative Care

Treating massive and complex abdominal defects does not start on the day before surgery. It is usually a long curvy path until final reconstruction and many issues should be anticipated with meticulous surgical strategy. A detailed plan with alternative options should be used for successful closure in these challenging situations.

When using complex abdominal reconstructive techniques in the open abdomen it is important to make sure all the intra-abdominal problems are resolved. The use of CT or other appropriate imaging is helpful and adequate. In these critically ill patients it is very important to assure they are in the recovery phase of their illness, with fluid control for an optimized negative fluid balance, good nutritional status, and exclusion of any major infection. Although surgical aggression promotes another catabolic phase before the final recovery phase, the closure of the open abdomen ends a vicious cycle of pro-inflammation. With this in mind, the patient should be at his best physiological status before reconstructive surgery.

Nutritional status is essential for the post-operative recovery and should never be underestimated before any kind of major abdominal reconstruction. Special consideration should be addressed towards the high output intestinal fistula. The intestinal rehabilitation previous to surgery is often a challenging difficult step for the patient, the family, and the physician. Dealing with high output enterocutaneous fistulae is an extra burden for a physically and mentally exhausted patient. Even when no nutritional parameters are altered except for weight lost over 10%, their physiological reserve is at the limit. These individuals may not be able to recover well after surgery, increasing the probability of infection, anastomosis breakdown, poor wound healing, and should be managed in an experienced unit [38].

Determining the size of the defect is a critical step for meticulous detailed surgery preparation and future success. Our measurement is estimated in two ways: (a) transverse and longitudinal measurements when the patient is lying down in the supine position. These parameters allow the calculation of the area of the hernia equivalent to that of an ellipse; (b) measurement of the defect with a CT scan in every patient prior to surgery. It is our experience that CT measurement is usually smaller comparatively to directly measuring the patient either pre or intra-operatively. However, CT scan measurements are more objective limiting any surgeon bias [15]. Another important aspect of ordering a CT scan before every reconstruction is the evaluation of the abdominal wall muscles status given that true successful anterior component separation technique relies on the integrity of these muscles. Therefore CT imaging and 3D CT reconstructions may be helpful to fully access the complexity of the abdomen and properly plan surgery and are used by the authors in any major reconstruction [39] (see Fig. 14.3).

Fig. 14.3

CT 3D reconstruction as a tool for pre-operative surgical technique programming

When dealing with planned ventral hernia s with previous skin graft , it is best to allow enough time before reconstruction, usually 9–12 months [38, 40], in order to lower the risk of bowel injury during adhesiolysis (see Fig. 14.4). Closure of patient skin without any grafts can be approached earlier.

Fig. 14.4

Skin pinch of the mature graft

Assessing healthy skin status is essential for a good outcome and independent from the reconstruction of the abdominal wall. It is crucial to anticipate lack of skin coverage and adequate surgical technique either through skin expanders or flaps.

Whenever possible, consideration must be taken to include the management of bowel and abdominal reconstruction in a single step or a two-step approach with bowel reconstruction before the definitive repair of the abdominal wall in order to avoid a contaminated procedure that may increase post-operative morbidity. This, however, has its risk, as patient will undergo two major operations. The authors experience, just as reported by others, that “one-stage” procedures are viable and, with the exception of superficial skin infections, do not increase morbidity [19, 20, 41].

Risk factors should be accessed and specially those known in the literature to predict post-operative complications like obesity, smoking, chronic pulmonary lung disease, immunosuppression, and diabetes [42]. The authors promote respiratory optimization/rehabilitation that prepares patients for a faster and uneventful post-op recovery.

Contamination also plays a role in pre-operative planning. Potential contamination may be expected with a previous wound infection, either superficial or deep, presence of a stoma or violation of the gastrointestinal tract. The presence or potential for contamination play a role in choosing the adequate mesh, at times in favor of a biologic, but there is still no consensus for the choice between a synthetic, biosynthetic, or biologic mesh [38, 43, 44].

During the anesthetic procedure it is extremely important to reduce intra-operative fluids to strictly the necessary amount. Goal-directed fluid policy has proven to be useful in reducing bowel edema and post-operative complications in a number of surgical areas [45]. We think this concept can also be safely applied when dealing with abdominal closure of massive defects. Good muscle relaxation is mandatory during the procedure in order to avoid excessive tension and technical difficulties. Thoracic epidural analgesia should be the standard of care as recent studies show a positive effect in lowering the intra-abdominal pressure. This type of specific analgesia leads to abdominal muscle relaxation lowering the risk of pulmonary associated complications. It is also associated with less post-operative complications in AWR [46].

Antibiotics are given 30 min prior to the beginning of surgery (except for vancomycin which is given 2 h before) and the choice depends on the type and degree of contamination of the wound and previous results of microbiologic cultures.

Finally, the surgery should be reviewed with the patient in order to discuss real patient expectations regarding cosmetic issues, because, eventhough almost always improved, they are definitely not the main goal of the surgery.

The success of this surgery requires on careful planning, attention to details of details and early involvement of other specialties as anesthesiology and the Intensive Care specialist when necessary in the whole process.

Surgical Technique

Clear pre-operative landmarks are drawn on the abdominal wall. This allows everyone on the team to perceive the anatomic landmarks and major defects, facilitating understanding and communication (see Fig. 14.5).

Fig. 14.5

Abdominal wall anatomical landmarks and defect (Fig. 18.6 from previous edition)

Step 1

Start with a 1–2 cm incision under the tip of the 11th rib, usually on the anterior axillary line. Continue dissection of the anatomical planes until the external oblique fascia is identified (see Fig. 14.6). Open the muscle fascia and make a blunt dissection of the underlying plane, between the external and internal oblique, in order to make Step 2 easier (see Fig. 14.7).

Fig. 14.6

Opening of the external oblique muscle fascia through a 1–2 cm incision on the tip of the 11th rib

Fig. 14.7

Blunt dissection of the underlying plane of the external oblique, making insertion of the trocar balloon easier

Step 2

Insert the trocar balloon (Spacemaker™ Plus Dissector System—Covidien, Dublin, Ireland) (see Fig. 14.8). After creating an avascular plane with blunt dissection between the muscles with the trocar balloon, connect it to the CO₂ insufflator aiming for an 8–12 mmHg pressure (see Fig. 14.9). Introduce a 10 mm 30° camera after removing the balloon (see Fig. 14.10).

Fig. 14.8

Insertion of the trocar balloon for blunt dissection of the avascular plane between the external and internal oblique muscles

Fig. 14.9

Connection of the CO₂ insufflator

Fig. 14.10

Insertion of a 10 mm 30° camera and introduction of a working 5 mm trocar in the posterior axillary line as it’s a difficult working angle

Step 3

Introduce a 5 mm trocar at the level of the posterior axillary line, in order to have a good dissection angle (see Fig. 14.10).

Make sure to identify the area above, the line of the fascia of the external oblique, 1 cm lateral to the semilunaris line, and cut the external oblique fascia all the way to the inguinal ligament (see illustrative Fig. 14.11). It is extremely important not to cut the semilunaris line or else a very complex defect will result.

Fig. 14.11

Trocar placement view and image projected on the screen. Section of the external oblique fascia lateral to the semilunaris line

Step 4

Introduce another 10 mm trocar in the right iliac fossa in order to extend the component separation 5–6 cm above the costal margin. Here it is important to use a cautious haemostatic dissection, as the muscular fibers tend to bleed.

Step 5

It is important along the process to make sure the external oblique is well dissected from the internal oblique in order to achieve the best rectus advancement.

Step 6

Sealed suction drains are placed through the most caudal trocar incision at the end of the surgery.

If a totally laparoscopic procedure is planned the surgery will proceed laparoscopic, midline closure is achieved in a shoelace manner, and a double layer mesh in an IPOM fashion is applied.

In massive defects laparoscopy is almost always technically challenging and not feasible. So, after video-assisted component separation the authors open the midline, and takedown any adhesions present which is many times a lengthy and meticulous job. Afterwards make the dissection of the posterior rectus sheath, close it with running suture long term absorbable monofilament 2/0 and preferably apply a retrorectus mesh and close anteriorly the linea alba. Sometimes it is not possible to totally close the posterior sheath but its mobilization allows us an extra few cm to achieve the necessary mobilization of the muscle complex formed by the rectus-internal oblique-transversus to slide over the midline and achieve closure (see Fig. 14.12a, b). When midline closure is not feasible then an IPOM procedure is made, with transfascial mesh fixation in the cardinal points and closure of fascia over mesh in order to diminish the bridging defect as much as possible. This can be challenging to achieve after a video-assisted component separation that lack the large skin flaps of open procedures. We use a “clock,” transabdominal technique, to secure the mesh with 12 corresponding “hour” sutures. The sutures are secured to the mesh and then passed through the abdominal wall with a suture passer. Some authors find it useful to introduce the laparoscope intra-abdominally at the end of the surgery and secure the rest of the mesh with tackers [47]. This may diminish the risk of bowel entrapment and difficulty in mesh incorporation which leads to increasing associated complications but it is not technically feasible for biologic meshes.

Fig. 14.12

(a) Dissection of the posterior rectus sheath. As it was impossible to close the sheath in the midline, a biological mesh was placed intraperitoneally and fixed with transabdominal sutures. Inferior partial closure of the posterior sheath was performed, with a running suture over the mesh. (b) Anterior rectus sheath closure with a running suture over a closed-suction drain

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Tags: Surgery of Complex Abdominal Wall Defects

Aug 19, 2017 | Posted by admin in ABDOMINAL MEDICINE | Comments Off

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Minimally Invasive Component Separation for the Repair of Large Abdominal Wall Defects