Medical anatomy of the stomach wall: hernia surgical procedure.OA Anatomy

Medical anatomy

The layers of the stomach wall embrace comfortable tissue and muscle. The superficial fascial layers differ above and beneath the umbilicus. Above the umbilicus, a single layer consists of the fused Camper and Scarpa fascia; beneath the umbilicus, these layers are separated. Camper fascia is the fatty outer layer and is steady inferiorly with the superficial thigh fascia and extends inferiorly into the labia majora in females and the scrotum in males. Scarpa fascia is the membranous internal layer that fuses inferiorly with the fascia lata of the thigh and continues posteriorly to the perineum the place it’s known as Colles fascia.

The deep fascial layers embrace the exterior indirect, inner indirect, transversus abdominis and parietal peritoneum. These buildings assist type the rectus sheath and transitions on the arcuate line. The arcuate line is situated halfway between the umbilicus and symphysis pubis. The anterior rectus sheath above the arcuate line is comprised of the exterior indirect and a part of the inner indirect. The posterior rectus sheath is comprised of the inner indirect and transversalis fascia. Beneath the arcuate line, the exterior and inner indirect muscle mass fuse to type the anterior rectus sheath with the posterior rectus sheath being made up of solely transversus abdominis (Determine 1). The anterior and posterior rectus sheaths encompass and help the rectus muscle, and these layers are sometimes used and manipulated for stomach hernia restore and reconstruction. The linea alba and linea semilunares are vital surgical landmarks. The linea alba runs within the midline from the xiphoid course of to the symphysis pubis and is comprised of a fusion of the anterior and posterior rectus sheath. The linea alba is usually used for surgical incisions, as a result of it permits fast and easy accessibility to the stomach cavity. The linea semilunaris is the lateral boundary of the rectus muscle and is comprised of the fusion of the exterior and inner indirect muscle mass and the transversus abdominis.

Determine 1: Image of proper rectus muscle exhibiting the layers above and beneath the arcuate line. The posterior rectus sheath above the arcuate line is made up of the inner indirect and transversalis fascia. Beneath the arcuate line, the posterior rectus sheath is made up of solely transversus abdominis fascia.

The principle muscle mass of the stomach wall embrace the rectus abdominis, exterior indirect, inner indirect, transversus abdominis and pyramidalis. The rectus abdominis muscle mass are paired and are within the midline. They serve a number of capabilities and are the precept flexors of the stomach wall. They stabilise the pelvis whereas strolling, defend the stomach viscera and assist in compelled expiration. The rectus originates from the pubic symphysis and crest, and inserts on the anterior surfaces of the fifth, sixth and seventh costal cartilages and the xiphoid course of. Three to 4 tendinous inscriptions run in a lateral route, adhere to the anterior rectus sheath and interrupt the rectus abdominis.

The lateral muscle mass of the stomach wall embrace the exterior and inner indirect muscle mass and transversus abdominis. Probably the most superficial muscle and thickest of those muscle mass is the exterior indirect, which originates from the decrease eight ribs, attaches medially to the pubic crest and programs in an inferomedial route. Inferiorly, the exterior indirect varieties the inguinal ligament extending between the anterior superior iliac backbone and pubic tubercle. The interior indirect muscle runs in a superomedial route, deep and perpendicular to the exterior indirect. It inserts on the inferior and posterior borders of the tenth by twelfth ribs superiorly and originates from the thoracolumbar fascia, anterior two-thirds of the iliac crest and lateral half of the inguinal ligament. Inferiorly, the inner indirect fuses with the transversus abdominis forming the conjoined tendon, which inserts on the pubic crest. The transversus abdominis runs in a horizontal route and is the deepest of the lateral muscle mass. It originates from the anterior three-fourths of the iliac crest, lateral third of the inguinal ligament, internal floor of the decrease six costal cartilages and interdigitates with fibres from the diaphragm. Beneath the arcuate line, it inserts into the pubic crest and pectineal line forming the conjoined tendon with the inner indirect. The pyramidalis muscle, absent in about 20% of individuals, is a small triangular muscle anterior to the inferior side of the rectus abdominis^[1]. The muscle mass of the stomach wall are proven in Determine 2.

Determine 2: The muscle mass of the stomach wall. Reprinted with permission from Chim H, Evans KK, Salgado CJ, Mardini S. In: Rosen M, editor. Atlas of stomach wall reconstruction. New York, NY: Elsevier; 2012.

Belly wall blood provide and innervation

Understanding the blood provide and innervation of the anterior stomach wall is vital for protected hernia restore. The blood provide to the stomach wall is advanced however will be simplified by breaking it down into three zones^[2] (Determine 3).

Determine 3: The blood provide to the stomach divided into three zones. Reprinted with permission from Chim H, Evans KK, Salgado CJ, Mardini S. In: Rosen M, editor. Atlas of stomach wall reconstruction. New York, NY: Elsevier; 2012.

Zone I consists of the higher and mid-central parts of the stomach wall and is bordered superiorly by the xiphoid course of and medial costal margins, laterally by the linea semilunaris and inferiorly by the inferior fringe of the umbilicus. The blood provide for this zone consists of the deep superior and deep inferior epigastric arteries, which converge at a degree between the xiphoid and the umbilicus; the inferior artery is the dominant vessel of the 2. The superior epigastric artery originates because the lateral thoracic artery bifurcates at roughly of the sixth rib stage. The deep inferior epigastric artery originates from the exterior iliac artery earlier than it programs medially, passing by the posterior rectus sheath halfway between the pubis and the arcuate line.

The superior and deep inferior epigastric arteries each run deep to the rectus abdominis muscle, anterior to the posterior rectus sheath, and supply blood provide to the muscle and the overlying pores and skin and subcutaneous tissue by musculocutaneous perforators. These perforators will be subdivided into medial and lateral perforators. They exist as longitudinal rows that run parallel to the stomach wall. Medial perforators are inclined to have a broader vascular territory as they cross the midline, whereas the lateral perforators are localised to their particular facet of the stomach. Understanding these perforators is vital when choosing an incision sort and selecting a technique of restore. The widespread midline incision will disrupt the medial perforators that cross midline, limiting the collaterals in zone I. When the subcutaneous tissue is separated from the anterior rectus sheath, resembling throughout an exterior part separation, the blood provide to this anterior tissue is undermined, as a result of a lot of the blood provide to this area depends on these musculocutaneous perforators.

Zone II consists of the inferior stomach wall. It’s bordered superiorly by the inferior fringe of the umbilicus (the inferior border of zone I) and runs the size of the anterior stomach wall to its lateral border on the midaxillary line. Its inferior border is the inferior fringe of the stomach cavity. The blood provide for this zone consists of the epigastric arcade, superficial inferior epigastric, superficial exterior pudendal and superficial circumflex iliac arteries. A serious part of the zone III blood provide, the deep circumflex iliac artery, has perforators that offer a portion of pores and skin in zone II. This space is posterior and cephalad to the anterior superior iliac backbone.

Zone III consists of the lateral stomach wall and is bordered superiorly by the costal margin, medially by the linea semilunaris and laterally by the midaxillary line. The blood provide to this zone consists of the musculophrenic, lumbar and decrease intercostal arteries; the latter is derived from the deep circumflex iliac artery. The musculophrenic artery is the second department of the inner thoracic artery at its bifurcation. It passes inferolaterally behind the seventh, eighth and ninth ribs, offering massive branches to the intercostal arteries and ultimately becoming a member of the lumber artery, supplying the lateral stomach wall. The lumbar and decrease intercostal arteries lie within the airplane between the transversalis and inner indirect muscle mass.

Innervation of the anterior stomach wall follows a segmental and dermatomal sample and consists of nerves originating from the ventral rami of T7-L1. These segmental nerves have vital sensory and motor capabilities. Particularly, the anterior and lateral cutaneous branches of the intercostal nerves T7-11, subcostal nerve T12 and iliohypogastric and ilioinguinal branches of L1 are concerned in these processes. Except the iliohypogastric and ilioinguinal branches, these nerves run in the identical airplane because the intercostal and lumbar arteries between the inner indirect and transversalis muscle mass. On the midline, the T7-9 branches provide the superior stomach wall from slightly below the xiphoid course of to the superior fringe of the umbilicus, T10 innervates the world across the umbilicus and T11-L1 provide the decrease stomach wall. Laterally, T7-12 branches present sensory innervation. The ilioinguinal and iliohypogastric nerves additionally present sensation to the internal thigh and scrotum or labia majora. These two nerves pierce by the inner indirect muscle and run between this and the exterior indirect muscle.

Motor innervation of the musculature of the stomach wall follows an identical sample. The rectus abdominis muscle is innervated by the decrease six intercostal nerves. The exterior indirect, inner indirect and transversus abdominis muscle mass are innervated by the decrease intercostal, the subcostal, and the iliohypogastric and ilioinguinal nerves. The nerves of the stomach wall are proven in Determine 4.

Determine 4: The nerve provide of the stomach wall. Reprinted with permission from Chim H, Evans KK, Salgado CJ, Mardini S. In: Rosen M, editor. Atlas of stomach wall reconstruction. New York, NY: Elsevier; 2012.

Belly wall hernias and related surgical strategies

A ventral hernia is a disruption or gap within the stomach wall and will be labeled as main, occurring de novo or incisional (hernias brought on by earlier incision and surgical procedure). Nearly all of hernias type within the weaker areas of the stomach wall the place there isn’t a muscle current and sometimes happen within the linea alba. Nevertheless, incisional hernias can happen wherever within the stomach. The chance components for creating an incisional hernia embrace a number of technical and affected person components^[3,4].

The 2 main surgical strategies described for restore of a ventral hernia are laparoscopic and open approaches. Mesh use decreases the recurrence price in ventral hernias, so mesh must be used normally^[5,6].

An open ventral hernias restore is normally wanted due to the placement of the mesh required or when the restore requires separations or releases of any of the stomach wall parts. Mesh repairs are typically labeled as onlay, bridge or sublay repairs, and the kind of restore is set by the place the mesh is positioned in relation to the hernia. Whereas there may be ongoing debate concerning the advantages of the onlay and sublay strategies, most surgeons agree that bridge repairs with mesh have an unacceptable hernia recurrence price and will solely be utilized in particular circumstances^[7].

The onlay restore (inserting the mesh above the hernia defect and fixing it to the exterior indirect and/or the anterior rectus sheath) has a number of potential advantages: it may be technically simpler, sooner and its use could keep away from getting into the stomach cavity and damage to the viscera. An vital precept of hernia restore pertains to vast mesh overlap of the defect and sufficient fixation. A great onlay restore sometimes includes elevating subcutaneous flaps to permit placement of mesh. One other tenet of hernia restore is that, when attainable, mesh must be used as a buttress to restore and the midline/linea alba must be closed and the rectus muscle mass reapproximated. Vital strategies can be utilized to assist in midline closure in massive or advanced hernias and are sometimes are known as part separations or myocutaneous or myofascial releases. Probably the most notable of those was first described by Ramirez et al.^[8] and includes slicing of the posterior rectus sheath, dissecting the subcutaneous tissue off the exterior indirect and incising the exterior indirect lateral to the semilunar line (Determine 5). Though this method is probably going essentially the most broadly identified, there are numerous myocutaneous and myofascial releases primarily based on the anatomy of the stomach wall that can be utilized to realize midline closure.

Determine 5: Open restore of ventral hernia with placement of mesh within the retrorectus area. Element separation/incision of the exterior indirect has been performed lateral to the semilunar line to permit for midline closure with out undue pressure over the mesh.

The sublay restore relies on the speculation that placement of mesh beneath the hernia defect and muscle mass will enable the stomach forces to assist preserve the mesh in place and is essentially primarily based on the retrorectus restore popularised by Rives et al.^[9], Wantz^[10] and Stoppa^[11]. The retrorectus restore was described by Rives and is considered among the best restore strategies for ventral hernias^[9]. On this restore, the posterior rectus sheath is lower simply off the linea alba (Determine 6), and the rectus muscle is dissected off the posterior rectus sheath. The posterior rectus sheath is then sewn collectively within the midline permitting for the mesh to be positioned on this area and excluding its contact with the viscera (Figure7). One disadvantage of the Rives restore is that the posterior rectus sheath is a finite sheath and limits the quantity of mesh that may be positioned laterally because the sheath ends. Thorough data of the anatomy of the stomach wall demonstrates that there are a number of planes that can be utilized for retromuscular mesh placement to facilitate the position of bigger meshes that may lengthen past the borders of the posterior rectus sheath. Three of those strategies have not too long ago been described. The preperitoneal restore^[12] includes slicing the peritoneum within the midline and creating the airplane laterally as wanted (Determine 8). The good thing about this method is that it permits for vast mesh overlap of the hernia defect; nonetheless, the drawbacks are that it may be a troublesome technical dissection and should not enable for a myofascial launch. Two modifications of the Rives restore have been proposed to doubtlessly assist with not with the ability to place mesh laterally to the semilunar line within the retrorectus restore. The primary described by Carbonell and colleagues^[13] includes incising the lateral border of the posterior rectus sheath and dividing the posterior aponeurosis of the inner indirect. The dissection proceeds laterally between the inner indirect and the transversus abdominis muscle permitting for a big area to position mesh^[13]. One criticism of this restore is that the dissection and the division in these planes on the lateral border of the posterior rectus sheath sometimes require the necessity for ligation of the neurovascular bundles supplying the rectus muscle. Though there have been no goal research defining the impact this has on stomach wall perform, that is lower than fascinating if it may be prevented. The second was described by Novitsky and coworkers^[14] and includes incising the posterior rectus sheath simply medial to the semilunar line proximal to the place the nerves insert into the rectus muscle. The transversus abdominis muscle is then divided and launched permitting entry to the preperitoneal area^[14] (Determine 9). The proposed advantages of this method are that it spares the neurovascular provide to the rectus muscle and permits for vast mesh placement lateral to the semilunar line within the preperitoneal area.

Determine 6: Open ventral hernia restore exhibiting a laparotomy incision with opening of the posterior rectus sheath simply off the midline. Dissection of this airplane on either side of the incision will enable for closure of the posterior rectus sheath and placement of a retroretcus mesh for hernia restore (Rives).

Determine 7: Open retrorectus (Rives) restore of ventral hernia with dissection and closure of the posterior rectus sheath. The mesh is positioned on this area so it is not going to have contact with the viscera, and the anterior fascia is closed over the mesh.

Determine 8: Laparotomy incision with the peritoneum dissected off of the posterior rectus sheath. Dissection of the preperitoneal area on either side of the incision permits for closure of the peritoneum within the midline and huge mesh placement that may go lateral to the semilunar line.

Determine 9: The transversus abdominis includes incising the posterior rectus sheath simply medial to the neurovascular provide after which incising the transversus abdominis muscle. This enables for wider mesh placement into the preperitoneal area, sparing of the neurovascular bundle and reduces the strain on the stomach closure.

The laparoscopic method relies on the retrorectus restore popularised by Rives^[12], and the mesh is positioned intra-abdominally. For the reason that mesh is positioned intra-abdominally, mesh must be rigorously chosen to make sure the compatibility with intra-abdominal placement. Intra-abdominal meshes typically are coated polypropylene, polyester meshes or expanded polytetrafluoroethylene^[15]. One potential disadvantage of the standard laparoscopic restore is that, though the hernia is being repaired and the potential for incarcerated or strangulated hernias is mounted, it is a bridging-type restore and doesn’t actually reconstruct the stomach wall. This disadvantage has been addressed by means of laparoscopic defect closure described by Novitsky et al.^[16]