Endoscopic Component Separation for Ventral Hernia Repair



Fig. 7.1
Abdominal wall musculature. The abdominal wall comprises four major muscle groups: rectus abdominis, external oblique, internal oblique, and transversus abdominis muscles





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Fig. 7.2
Cross-sectional view of the abdominal anatomy. The arcuate line plays an important role as it demarcates the lower limit of the posterior layer of the rectus sheath and is also where the inferior epigastric vessels perforate the rectus abdominis



Abdominal Wall Vasculature


The vasculature of the abdominal wall is made up of a complex collateral system (Fig. 7.3). The inferior deep epigastric artery branches from the external iliac artery and is the dominant vascular supply to the anterior abdominal wall. It ascends superficially to the transversalis fascia and crosses the lateral border of the rectus muscle at the arcuate line where it enters the posterior rectus sheath. It then branches extensively and develops a collateral system with the superior deep epigastric artery, which is a terminal branch of the internal thoracic artery. The inferior deep epigastric vessels are bounded only by loose areolar tissue below the arcuate line and are susceptible to avulsion and hematoma during hernia surgery [33]. The musculocutaneous perforating vessels of the inferior deep epigastric artery reach and supply deeper tissue as well as the integument of the anterior abdominal wall. These perforators are particularly relevant in reconstructive surgery as an important supply for abdominal tissue flaps used [29]. The number, location, and course of these perforators are highly variable. The venous supply of the anterior abdominal wall tends to be more variable than arterial pathways, but veins typically follow the course of arteries. Above the umbilicus, veins tend to drain to the subclavian vessels, and below the umbilicus, they drain to the external iliac vessels. Veins may be dilated in patients with chronic liver disease, portal hypertension, and renovascular disease. Special consideration and careful preoperative planning must be engaged to avoid complications in these patients [31].



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Fig. 7.3
The vasculature of the abdominal wall is made up of a complex collateral system


Abdominal Wall Innervation


Knowledge of the innervation of the abdominal wall is paramount as denervation of these muscles can compromise their function and place the patient at increased risk of incisional hernia and complications secondary to herniosis. The thoracoabdominal nerves (T7–T11), subcostal nerves (T12), ilioinguinal nerves (L1), and iliohypogastric nerves (L1) all travel between the internal oblique and transversus abdominis muscles (Fig. 7.4). Careful attention must be given to the dissection around these structures during both open and endoscopic component separation approaches to hernia repair in order to protect the viability of the innervation, and therefore the function of the muscles involved in the integrity of the abdominal wall. Avoidance of the space between the internal oblique muscles and the transversus abdominis muscle will help to minimize denervating injuries to the abdominal wall during abdominal wall surgery.



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Fig. 7.4
Anterior abdominal wall innervation. The thoracoabdominal nerves (T7–T11), subcostal nerves (T12), ilioinguinal nerves (L1), and iliohypogastric nerves (L1) all travel between the internal oblique and transversus abdominis muscles



Impact of Abdominal Wall Hernia on Abdominal Wall Mechanics


Jean Rives , one of the first surgeons to acknowledge the complex pathophysiology hernias, noted that the abdominal wall loses synergy with the diaphragm with resultant protrusion of the viscera with respirations. This subsequently leads to the development of lumbar lordosis as a compensatory mechanism for patients to maintain their center of gravity and later results in lower back pain. The lack of counterbalance to the back muscles causes the lateral abdominal wall muscles to retract and fibrose, thus worsening the protrusion of the abdominal contents [36, 38]. Dermatologic changes such as ischemic ulcers of skin are frequently late-stage events in the disease process of herniosis, especially when they occur in combination with other comorbid conditions such as decompensated cirrhosis, smoking, or uncontrolled diabetes mellitus [2, 4, 17, 31].


Open Hernia Repairs and Components Separation Techniques



Primary Hernia Repair


The incidence of incisional hernia after midline laparotomies ranges from 10 to 20 %, while the recurrence rate following hernia repair with primary suture closure techniques varies from 25 to 52 % [47]. In one study of abdominal closure rates with mesh after trauma laparotomy and damage control, the hernia development rate at 4 years was 67 % for the total, 13 % for patients with delayed fascial closure, and 80 % for patients requiring other closure techniques. Vacuum-assisted closure seems to reduce the incidence in other trials.

The increased incidence in recurrence relative to the incidence of initial incisional hernia formation suggests that factors beyond technique impact hernia formation. Approaches to hernia repair aim to reattach tendons of the lateral abdominal muscles in an effort to reconstruct the abdominal [6, 36]. Relaxing incisions such as the Gibson or Clotteau–Premont may facilitate a tension-free repair, although patient outcomes were disappointing [37, 43]. Stoppa popularized a technique for hernia repair in which an unsutured Dacron patch was placed between the peritoneum and the muscular layers due to his belief that relaxing incisions induce unnecessary parietal damage and increase the likelihood of hernia recurrence despite attempts to reduce tension (Fig. 7.5) [7, 44]. The procedure initially described by Stoppa remains a commonly utilized technique for ventral hernia repair and is often considered the gold standard for hernia repair. Contemporary studies clearly demonstrate improvements in recurrence rates with the utilization of prosthetic mesh during incisional hernia repair [16]. However, due to risk of infection , previous mesh infections, or contaminated spaces such as chronic wounds of fistulas, not all patients are candidates for synthetic mesh placement [22, 32, 33, 45]. An additional drawback of a mesh hernia repair may be the loss of abdominal wall function, particularly when utilized to bridge hernia defects. Bridging mesh has been found to reduce overall abdominal wall torque relative to a suture-based primary closure of the abdominal wall musculature [11], although the clinical relevance of these findings remains unproven.



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Fig. 7.5
Retro-rectus hernia repair. The retro-rectus hernia repair or Rives–Stoppa repair involves dissection of the posterior rectus sheath from the rectus abdominis muscles. The posterior sheath is dissected from the rectus abdominis muscles in an avascular plane (a). The posterior rectus sheath and peritoneum are closed (b). In the event the peritoneum is unable to be closed, an absorbable mesh is sutured as an inlay to the posterior sheath (c). Mesh is placed in the retro-rectus space sutured circumferentially (d), resulting in opposition of the midline fascia (e). Closed suction drains are placed in the preperitoneal space prior to midline closure (f)


Component Separation Techniques


Complex hernias XE “Hernia:repairs:Stoppa’s technique:complex” frequently necessitate reconstructive procedures due to challenges associated with contamination, infection, defect size, loss of abdominal wall tissue, prior or existing stomas, and previous surgical procedures. Tissue transfer by means of rotational and free flaps may be utilized for soft tissue coverage (Fig. 7.6). These flaps are often reserved for patients with the most complex hernias due to the morbidity associated with these techniques. In an attempt to close abdominal wall defects without remote tissue transfer, Ramirez et al. described a technique based on the premise that separation of the muscular components of the abdominal wall would allow mobilization of each unit over a greater distance than possible by mobilization of the entire abdominal wall as a block [35]. Their technique required separation of the posterior rectus sheath from the rectus abdominis muscle, elevation of the skin and subcutaneous tissues from the anterior abdominal wall to the linea semilunaris, and division of the external oblique aponeurosis with separation of the external and internal oblique muscles. The compound flap of the rectus muscle, with its attached internal oblique–transversus abdominis muscle, can be advanced 10 cm around the waistline and up to 20 cm bilaterally (Fig. 7.7). Their study suggested that large abdominal wall defects might be reconstructed with functional transfer of abdominal wall components without the need for resorting to distant transposition of free muscle flaps. Other authors developed similar techniques for components separation, although the Ramirez technique is the most widely popularized [12, 13, 18, 19, 24, 26, 42, 48]. The elevation of large undermining skin flaps and division of the perforating musculocutaneous vessels of the abdominal wall skin resulted in significant wound complications, including seroma and skin necrosis [10, 28]. Some studies have reported major wound morbidity in up to 40 % of patients, prompting the development of perforator-preserving component separation in the repair of incisional hernias [15]. These perforator-preserving component separations may be performed through a midline incision, incisions on the lateral abdominal wall, or utilizing endoscopic techniques . Although the technical details of each of these procedures vary, the preservation of the blood supply to the abdominal wall skin originating from the epigastric arteries is their common objective as this is crucial for reducing wound morbidity and improving outcomes.



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Fig. 7.6
Free tissue transfer for non-healing anterior abdominal wound. The patient shown in this figure required soft tissue coverage after wound healing complications in conjunction with a complex abdominal wall hernia. Tissue transfer by both rotational and free flaps may be utilized for soft tissue coverage in patients with complex hernias and loss of domain (see Chap. 6). These flaps are often reserved for patients with the most complex hernias due to the morbidity associated with these techniques



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Fig. 7.7
Endoscopic components separation technique/laparoscopic ventral hernia repair. The endoscopic technique for component separation is performed to minimize wound morbidity associated with the Ramirez component separation technique. A 2-cm transverse incision is made at the anterior axillary line (lateral to the linea semilunaris) approximately 5 cm cephalad to the costal margin. Dissection is performed until the inferomedially oriented fibers of the external oblique muscle are identified (a). The external oblique fibers are subsequently separated bluntly to expose the underlying internal oblique aponeurosis. A balloon dissector is then inserted into the inter-oblique space parallel to the linea semilunaris and insufflated to dissect the potential space between the internal and external oblique muscles (b). An additional 5-mm trocar is inserted laterally to divide the external oblique aponeurosis from above the costal margin inferiorly to the inguinal ligament (c). Dissection into the subcutaneous adipose tissues to the level of the subcutaneous fascia maximizes advancement (d). Endoscopic component separation may be utilized as an adjunct to laparoscopic ventral hernia repair to facilitate hernia defect closure with transcutaneously placed horizontal mattress sutures (e). Pneumoperitoneum is reduced while tying sutures externally (f) to allow for a tension-free defect closure (g, h)


Subcutaneous Endoscopic Component Separation Technique


The initial descriptions of an endoscopic component separation technique were developed in order to minimize operative injury to the vasculature of the abdominal wall and decrease postoperative wound dehiscence by utilizing subcutaneous balloon dissection to develop the operative space [23]. Balloon dissectors, frequently used in laparoscopic extraperitoneal inguinal hernia repairs , were placed in the subcutaneous space of the anterior abdominal wall lateral to the linea semilunaris. Following balloon dissection, additional ports were placed into the abdominal wall in order to enable division of the external oblique aponeurosis from the inguinal ligament to the costal margin or above. This technical advance mimicked the Ramirez component separation technique while eliminating the need for undermining skin flaps. The endoscopic component separation technique reduced the incidence of wound infection , ischemia, and dehiscence without impacting hernia recurrence rates. In 2013, Daes et al. refined this technique by developing an alternative method in which preoperative skin marking of the semilunar line under ultrasonic guidance precedes creation of a subcutaneous space with a balloon trocar and division with undermining of the external oblique aponeurosis. This ultrasound guidance enables clear identification of anatomic landmarks [8]. Recognition of the linea semilunaris represents one of the most important facets of component separation procedures, as inadvertent division of the linea semilunaris may predispose patients to lateral abdominal wall hernia formation.


Endoscopic Component Separation: “Inter-Oblique” Techniques


Initial descriptions of endoscopic component separation were described as a more feasible alternative to the subcutaneous component separation technique. The initial description by Maas et al. involved a midline laparotomy for adhesiolysis followed by a 2–4-cm incision placed on the lateral abdominal wall bilaterally lateral to the rectus abdominis muscle [25].

A balloon dissector is then used to create a space between the external and internal oblique by insufflation under video-endoscopic guidance, thus dissecting the “inter-oblique” space. Following removal of the dissecting balloon, the external oblique is retracted through this small incision and a 30° laparoscope is utilized to visualize and divide the external oblique aponeurosis, thus creating a compound flap while taking care not to shift the skin from the rectus muscle. Their proposed technique is attractive for the repair of large midline incisional hernias without the use of prosthetic material. The use of the distention balloon and video-endoscope minimizes tissue trauma and preserves the blood supply of the skin through the epigastric perforators. This is a major benefit in patients in whom the reconstruction is performed in a contaminated environment. Further work led to the development of less invasive techniques that are comparable in safety and acceptability.

Subsequent descriptions of laparoscopic component separation techniques were built upon the initial descriptions by Maas et al. [15, 40]. The laparoscopic component separation technique involves placement of a low anterior costal incision, dissection between the external and internal oblique muscles, and placement of a balloon dissector to create a space between the muscular structures. Subsequently, two additional ports are placed into the lateral abdominal wall which may be utilized to divide the external oblique aponeurosis, allowing for the medialization of the rectus abdominis muscle toward the midline. In this initial description of seven patients involving the single-stage treatment of patients with infected mesh, only one superficial wound complication occurred, suggesting a benefit to this minimally invasive approach.

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Jun 13, 2017 | Posted by in ABDOMINAL MEDICINE | Comments Off on Endoscopic Component Separation for Ventral Hernia Repair

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