LECTURE 5.
OPERATIVE SURGERY OF VENTRAL ABDOMINAL WALL
Abdomen as anatomiacal subject is a part of a trunk, which is located between the diaphragm and pelvic inlet.
Borders of abdomen are:
– from above – xiphoid process and rib arch
– from below – iliac crest, inguinal fold, superior border of symphisis
– from sides – vertical Lesgaft’s line, which connects the end of XI rib with the iliac crest.
Walls of abdomen are:
– superior wall is diaphragm
– posterior – lumbar vertebrae with muscles, which attach to backbones
(m. iliolumbalis, m. quadratus lumborum, extensors of a trunk)
– anterior and lateral walls consist of muscles of abdominal press
– lower wall is absent, that is why loops of small intestine can easily move in pelvic cavity. At the same time organs of small pelvis can easy move in abdominal cavity (during pregnancy).
There are some anatomical landmarks at the ventral abdominal wall:
1. Xiphoid process – easily palpated in the place where rib arches converge. Connection between sternum and xiphoid process located at level of 9th thoracic vertebrae.
2. Rib arches, which is formed by 7, 8, 9, 10 costal cartilages. Lowest level of arch is opposite to 3rd lumbar vertebrae.
3. Crest of the iliac bone. The highest point of the crest located opposite to the 4th lumbar vertebrae.
4. Inguinal ligament. It’s lowest border of aponeurosis of external oblique muscle between the superior iliac spine and pubic tuber.
5. Pubic joint – cartilage that located at abdominal midline between the pubic bones.
6. Middle point of inguinal ligament. Here it is possible to feel a pulsation of external iliac artery because this artery continues in femoral artery just in this place.
7. Superficial inguinal ring – triangular aperture in aponeurosis of external oblique muscle, which is located above and medial to pubic tuber.
8. Midline (alba line) – fibrose formation, which located between pubic joint, and xiphoid process.
9. Umbilicus – scar on a place of attachment of umbilical funicle, which lies on abdominal midline.
10. Semilunar line – is corresponded to lateral border of rectus abdominis muscle, and crosses the rib arch on the apex of the 9th rib.
11. Transpyloric plane – correspondes to line, which connects apexes of cartilages of 9th ribs or passes through the points where rectus muscle crosses the costal arches. Plane crosses the pyloric part of stomach, gallbladder, duodeno-jejunal junction, corpus of pancreas, and gate of left kidney.
From clinical reasons the ventral abdominal wall is divided into 9 regions by two vertical and two horizontal lines. Vertical lines pass along external edges of rectus abdominal muscle. Superior horizontal line connects the lowest points of costal arches and lies opposite to 3rd lumbar vertebra. Inferior horizontal line connects upper-anterior iliac spines. It is located opposite to 5th lumbar vertebra. Thus, in the epigastric part are:
– pair (left and right) subcostal region and
– unpair – epigastric region.
In middle part are:
– umbilical region and
– two lateral (left, right) regions.
In hypogastric part are:
– pubic region and
– left and right inguinal regions.
Organs of abdominal cavity are projected on these regions of ventral abdominal wall.
The liver (right part), gallbladder, right flexure of colon, upper part of right kidney with suprarenal gland are projected on right subcostal region.
Left part of liver, stomach, upper half of duodenum, pancreas, abdominal aorta, celiac trunk and celiac plexus – epigastric region.
Cardiac part and fundus of stomach, spleen, left flexure of colon, upper part of left kidney with suprarenal gland, pancreas tail – left subcostal region.
Ascending colon, right kidney, loops of ileum intestine, right ureter – right lateral region.
Transversus colon, lower half of duodenum, large curvature of stomach, gate of kedneys, abdominal aorta and inferior cava vein. – umbilical region.
Descending colon, left kidney, loops of small intestine, left ureter – left lateral region.
Loops of small intestine, urinary bladder, lower part of ureters – pubic region.
Caecum with apendix, final part of ileum intestine, right ureter – right inguinal region.
Sigmoid colon, loops of small intestine, left ureter – left inguinal region.
Layers of ventral abdominal wall
In total, abdominal wall can be divided into 3 parts: 2 lateral (left, right) and middle. Lateral parts are located between costal arches and iliac crestswith inguinal ligaments. It continues in middle part as aponeurosis.
Lateral part:
– skin
– subcutaneous tissue. Very many vessels pass to the skin through this layer.
– superficial fascia, that consists of two laminae – superficial and deep. Superficial lamina continues in femoral fascia above the inguinal ligament.
– proper fascia, that cover abdominal muscles (external oblique, internal oblique, transversus, rectus and pyramidal muscles).
– external oblique abdominal muscle arises from lateral parts of 8 lower ribs.
– internal oblique abdominal muscle arises from lateral part of posterior edge of inguinal ligament and attaches to lower edge of 12, 11, 10 ribs, xiphoid process and alba line. Lower edge of this muscle is free.
– transversus muscle arises from internal surface of six costal cartilages, lumbar fascia, iliac crest. It attaches to xiphoid process, alba line, pubic joint.
– transversus fascia
– epiperitoneal fat
– parietal peritoneum.
Ventral part
Middle part of ventral abdominal wall is formed by 2 rectus muscles, which arises from pubic joint and pubic tuber. This muscle attaches to 5, 6, 7 ribs’ cartilages and xiphoid process.
The pyramidal muscle attaches to the anterior surface of rectus muscle in lower part of it. Pyramidal muscle arises from anterior surface of pubic bone and fix up to alba line.
Because of different anatomy of rectus muscle sheath surgeons recognize some levels of anatomical structures of rectus muscle sheath:
A) Above the costal arch anterior wall of sheath of rectus muscle is formed by aponeurosis of external oblique muscle. Posterior wall – by cartilages of 5, 6, 7 ribs and intercostal arches.
B) Second part of sheath is located between two lines, first of them connects lower points of costal arches, and second line connects anterior-superior iliac spines. In this part anterior wall of sheath is formed by aponeurosis of external oblique muscle and superficial lamina of aponeurosis of internal oblique muscle. Posterior wall of sheath is formed by deep lamina of internal oblique muscle aponeurosis with aponeurosis of transversus muscle.
C) Third part is located between pubic bone and line, which connects anterior-superior iliac spines. Aponeurosis of all muscles form anterior wall of sheath at this level. Posterior wall is formed by transversus fascia.
D) Fourth part of sheath is located in front of pubis. Anterior wall of rectus and pyramidal muscles covered by aponeurosis of three muscles. Posterior wall is formed by pubic bone.
There are some weak places on abdominal wall:
– umbilical ring
– alba line
– inguinal space (gap)
– external ring of inguinal canal
– internal ring of inguinal canal
– inguinal region.
Sources of blood supply
Cutaneous arteries, which are branches of the superior and inferior epigastric arteries, supply the area near the midline, and branches from the intercostal and lumbar arteries supply the flanks.
The venous blood is collected into a network of veins that radiates out from the umbilicus. The network is drained above into the axillary vein via the lateral thoracic vein and below, into the femoral vein via the superficial epigastric and great saphenous veins. A few small veins, the paraumbilical veins, connect the network through the umbilicus and along the ligamentum teres to the portal vein. They form an important portal-systemic venous anastomosis. The superficial veins around the umbilicus and the paraumbilical veins connecting them to the portal vein may become grossly distended in cases of portal vein obstruction. The distended subcutaneous veins radiate out from the umbilicus, producing the clinical picture referred to as caput Medusae.
In superficial layers of inguinal regions are:
– epigastric superficial artery
– circumflex ileum artery
– external pudental artery.
All these arteries arise from the femoral artery.
The same named veins fall into v. saphena magna.
In deep layers
The superior epigastric artery, one of the terminal branches of the internal thoracic artery. It supplying the upper central part of the anterior abdominal wall, and anastomoses with the inferior epigastric artery.
The inferior epigastric artery is a branch of the external iliac artery just above the inguinal ligament. It supplying the lower central part of the anterior abdominal wall, and anastomoses with the superior epigastric artery.
The deep circumflex iliac artery is a branch of the external iliac artery just above the inguinal ligament. It supplies the lower lateral part of the abdominal wall.
Venous drainage. The superior epigastric, inferior epigastric, and deep circumflex iliac veins follow the arteries of the same name and drain into the internal thoracic and external iliac veins. is carried out to systems of superior and inferior cava veins. Thus, cava-caval shunt (anastomoses) formes in umbilical region by anastomoses of superior and inferior epigastric veins. Well developed net of porto-systemic anastomosis also is present in this region, as I told you earlier.
Lymphatic drainage. The cutaneous lymph vessels above the level of the umbilicus drain into the anterior axillary lymph nodes. The vessels below this level drain into the superficial inguinal nodes.
The nerves of the anterior and lateral abdominal wall supply the skin, the muscles, and the parietal peritoneum. They are derived from the anterior rami of lower six thoracic nerves and the first lumbar nerves. The thoracic nerves are represented by the lower five intercostal and the subcostal nerves, and the lumbar nerve is represented by the iliohypogastric and ilioinguinal nerves. Directions of nerves is horizontal, they lay between internal oblique and transversus muscles.
If we know layer structure, blood supply, innervation of the ventral abdominal wall we can give substantiation and evaluation of abdominal wall incision.
So, demands to incisions:
First of all, each incision shoud be placed most close to the organ, on which operation will be conduct.
Secondly, it must have sufficient length, that not limit surgeon activity.
And third, surgical incision must be atraumatic, that minimised nerves, vessels and soft tissues injury.
Best incision is done along the natural lines of cleavage of the skin betweeervous trunks.
All incisions of the ventral abdominal wall are divided into 3 types:
– direct (vertical, horizontal)
– oblique
– combined.
Direct:
1) middle laparotomy – incisions of ventral abdominal wall along alba line
2) paramedian laparotomy – incision along internal edge of rectus muscle. It can be performed above the umbilicus for exposure of to organs of upper compartment of abdominal cavity or below the umbilicus – for exposure of to organs of lower compartment of abdominal cavity or pelvic cavity.
3) pararectal laparotomy – incision along external edge of rectus muscle.
4) transrectal laparotomy – incision through the mass of rectus muscle (in case of surgery named stomy – gastrostomy, for example).
5) transversus laparotomy – is performed horizontally and parallel to direction of nerves and elastic fibres. Pfanenshtil’s access – parallel to pubic joint without cutting rectus muscles during surgery on uterus, and Cherni’s access – the same incision, but with cutting of rectus muscles.
6) oblique laparotomy. It is performed parallel to costal arches for exposure of to liver, gallbladder, spleen in epigastric region, and parallel to inguinal ligament for exposure of to appendix, caecum, sigmoid colon in hypogastric region.
7) combined incisions (thoracoabdominal) – give wide access to organs but they are extremely traumatic.
8) angular laparotomy – carried out in case of necessity change direction of incision.
Anatomy of inguinal region
In this region inguinal herniae can be occur.
For understanding surgical anatomy and operative treatment of inguinal herniae we must stay on structure of inguinal canal. This canal is oblique tunnel above inguinal ligament. There are two rings and four walls in this canal. Superficial ring – it’s triangle hole in aponeurosis of external obligue muscle, that is located above and medial to the pubic tuber. It’s limited by two peduncles – medial and lateral. Deep ring attaches to lateral fossa of ventral abdominal wall (from inside). This ring lies on
Anterior wall of inguinal canal is formed by aponeurosis of external oblique muscle.
Posterior wall is formed by transversus fascia.
Inferior wall is formed by inguinal ligament.
Superior wall is formed by lowest fibers of transversus muscle.
In case of inguinal hernia topography of canal’s walls changes. Because of atrophy and separation of internal oblique muscle from inguinal ligament, anterior wall will be formed just by aponeurosis of external oblique muscle, and superior wall – by internal oblique muscle and transversus muscle. That is why herniae can be occur in this region.
The spermatic cord passes through the inguinal canal in male, and the round ligament of uterus passes through this canal in female.
Spermatic cord is complex of structures, which is covered by internal fascia. Cremaster muscle, iliohypogastric nerve, genital branch of genitofemoral nerve are above this fascia.
Structures of spermatic cord:
1) deferent duct. It can be palpated in upper part of scrotum.
2) testicular artery – branch of abdominal aorta, which arises on level of L2.
3) testicular vein – falls into renal vein on left side, and into inferior caval vein on right side. This fact can explain development of varicocele in left testicle.
4) cremaster artery – branch of inferior epigastric artery
5) artery of deferent duct – branch of inferior cystic artery
6) genital branch of genitofemoral nerve
7) sympathetic nerves
8) lymphatic vessels.
What is the hernia?
It’s the exit of organs of abdominal cavity through the natural or artificial holes of abdominal wall. Parietal peritoneum forms hernial sac.
Each hernia has:
– gate
– sac
– hernial contents.
Gate – hole in abdominal wall, through which organs pass from abdominal cavity under the skin.
Ø umbilicus ring is the gate for umbilical hernia
Ø internal ring of inguinal canal – indirect inguinal hernia
Ø inguinal space – direct inguinal hernia
Ø holes of alba line – herniae of alba line.
Hernial sac consist of neck, body, and fundus.
Hernial contents – parts of abdominal cavity organs, which are within the hernial sac.
Let’s stay on the surgical anatomy of inguinal herniae. It’s two types of this herniae: direct and indirect.
Indirect hernia:
– gate – internal inguinal ring
– sac is located laterally to the spermatic cord
– sac is located laterally to the inferior epigastric artery
– it has oval form
– it can be acquired or congenital.
Direct hernia:
– gate – inguinal space
– sac is medially to the spermatic cord
– sac is medially to the inferior epigastric artery
– it hasn’t connection with the spermatic cord, thus don’t cover by general tunic
– It has round form
– It can be only acquired.
The presence of the inguinal canal in the lower part of the anterior abdominal wall in both sexes constitutes a site of potential weakness. It is interesting to consider how the design of this canal attempts to lessen this weakness.
Except in the newborn infant, the canal is an oblique passage with the weakest areas, namely, the superficial and deep rings, lying some distance apart.
The anterior wall of the canal is reinforced by the fibers of internal oblique muscle immediately in front of the deep ring.
The posterior wall of the canal is reinforced by the strong conjoint tendon of the internal oblique and transversus muscles immediately behind the superficial ring.
In case of sharp temporary increasing of intra-abdominal pressure (coughing, straining, as in micturition, defecation, and parturition) the muscles of superior wall contract and bring superior wall nearer to the inferior wall. On coughing and straining, as in micturition, defecation, and parturition, the arching lowest fibers of the internal oblique and transversus abdominis muscle contract, flattening out the arched roof so that it is lowered toward the floor. The roof may actuallycompress the contents of the canal against the floor so that the canal is virtually closed.
Operative treatment of herniae
Consists of three steps:
– access
– extract of hernial sac
– hernioplasty
Access – carry out by incision on
Surgeon strengthen the anterior wall in case of indirect inguinal herniae.
The basic methods are:
Gerar’s method: – internal oblique muscle and transverse muscle suture to inguinal ligament;
– then suture aponeurosis of external oblique muscle to this ligament;
– performe duplication by suturing of inferior edge of aponeurosis to its’ upper edge.
Spasokukotskyy’s method: – internal oblique, transverse muscle and aponeurosis of external oblique muscles suture to inguinal ligament
– performe duplication.
Kimbarovskyy’s metod: – aponeurosis of external oblique muscle covers internal and transversus muscle
– suturing to the inguinal ligament
– performe duplication
Martunov’s method: – external oblique muscle is sutured to the inguinal ligament
– performe duplication.
Surgeon strengthen the posterior wall in case of direct inguinal herniae:
Bassini method: – stitching of transversus and internal oblique muscles to inguinal ligament
– put spermatic cord oew posterior wall
– stitching of aponeurosis of external oblique muscle.
Kukudzanoff’s method: – decrease of inguinal space by stitching of rectus muscle sheath to lacunary ligament
– next steps are the same as in case of Bassini’s method.
Sliding hernia – in that cases if one wall of hernial sac is formed by a caval organ, covered by peritoneum from one or three sides (urinary bladder, caecum).
Incarcerated (parietal Richter’s)hernia – sudden compression of hernial contents within the hernial gate. Different organs may be compressed. Necrosis of organs’ wall can be occur as result of compression. It leads to development of general (diffuse) peritonitis.
