Splenic Conditions Flashcards
What are the functions of the spleen?
The spleen is primarily a filter, which removes old and damaged red blood cells and platelets.
It also contains immunological cells, including T- and B-cells and reticuloendothelial cells, which remove opsonized bacteria and other particles from the blood.
What is the surgical anatomy of the spleen?
The spleen is roughly divided into three sections: the upper pole, the body and the lower pole.
The arterial supply and venous drainage of the upper pole is from the short gastric vessels, the body is supplied by the main hilar vessels, and the lower pole is supplied by gastroepiploic and omental vessels.
The main splenic artery is a branch of the celiac artery, and the main splenic vein joins the superior mesenteric vein to form the portal vein which then drains into the liver.
The spleen is fixed to the diaphragm and to the lateral abdominal wall by peritoneal attachments which prevent torsion or volvulus of the spleen.
What are the steps of a splenectomy?
The steps of a splenectomy are
- Division of the attachments to the diaphragm and retroperitoneum,
- Division of the lower pole vessels,
- Division of the hilar vessels,
- Division of the short gastric vessels,
- Removal of the spleen, and
- Identification and excision of accessory spleens.
In most cases, the operation can be done laparoscopically, in which case division of the lateral attachments are often done at the end of the procedure after division of the vessels, and the spleen is placed into a bag inside the abdomen so the neck of the bag can be brought out through a port site and the spleen can be morcellated within the bag and removed in pieces.
What is the technique of partial splenectomy?
The goal of a partial splenectomy is to leave a sufficient amount of spleen behind to retain splenic function (although it is not known exactly how much residual spleen is necessary for that purpose).
For spherocytosis, the preferred approach is to divide the lower pole vessels and the main hilar vessels, leaving the upper pole based on the short gastric vessels and stabilized with the phrenosplenic connec- tions.
For a splenic cyst or mass, the surgeon must assess the blood supply to the affected segment and make a decision which part of the spleen to leave behind with an intact blood supply.
Because the spleen is very hard in patients with spherocytosis, the spleen must be divided with a sealing device; in patients with a splenic cyst or mass the residual normal spleen can usually be divided with a stapler.
What is the best management for splenic trauma? [1]
Most children with splenic injury can be managed non-operatively with activity restriction and fluid resuscitation.
The indications for transfusion include unstable vital signs after receiving 20 cc/kg of isotonic fluid, a hemoglobin level of less than 7.0 gm/dl, or signs of active bleeding.
The indication for emergency splenectomy is persistent hemodynamic instability despite blood transfusion.
If laparotomy is necessary, the surgeon should attempt to salvage some or all of the spleen if possible.
For those managed non-operatively, discharge can be done when the child is stable and eating, and activity limitation should be maintained for injury grade + two weeks.
What are the indications for splenectomy in children with immune throm- bocytopenia purpura (ITP)?
ITP is an immunological condition in which the child makes antibodies to his own platelets, which are then destroyed by the spleen.
Most children have the acute form that resolves on its own.
Many children with the chronic form can be successfully treated medically with steroids or intravenous immunoglobulin (IVIG).
Splenectomy is recommended for those who have persistent recurring thrombocytopenia despite medical therapy, or for those who have complications from the medical therapy itself.
What are the perioperative considerations when doing a splenectomy for a child with ITP?
Ideally, the platelet count should be at least 50,000 at the time of splenectomy.
This can usually be accomplished by treating with IVIG within a week of the planned surgery.
For those who cannot achieve an adequate platelet count, platelets should be infused just prior to surgery and continued until after the arterial supply to the spleen has been taken.
Key technical points during the surgery include ensuring that the spleen is completely excised without spilling any splenic tissue, and ensuring that any accessory spleens are identified and excised.
What should be done with a child who has persistent or recurrent thrombocytopenia after a splenectomy for ITP?
The two main reasons for thrombocytopenia after a splenectomy are retained accessory splenic tissue, or breakdown of platelets by reticuloendothelial cells in the liver or bone marrow.
A nuclear spleen scan should be done to identify any residual splenic tissue, and if found this tissue should be removed at a second operation.
What are the indications for splenectomy in children with sickle cell disease (SCD)?
Most children with SCD undergo auto-amputation of the spleen by the age of 10 or so and are therefore not candidates for splenectomy.
However, a small minority will develop a sequestration crisis before that time, which can result in extremely low hemoglobin levels and can be fatal.
Therefore, any child with SCD who has had even one sequestration crisis should have a splenectomy.
What are the perioperative considerations when doing a splenectomy for a child with sickle cell disease? [2]
Children with SCD are susceptible to acute chest syndrome after a general anesthetic and surgical procedure, which can be severe and even fatal.
There is general agreement that these children should be well-hydrated and should have an adequate hemoglobin level prior to surgery, but there is continuing controversy about what that level should be, and whether routine preoperative transfusion is beneficial.
Postoperatively it is important to maintain hydration and hemoglobin level, and to adequately prevent postoperative pain.
What are the indications for splenectomy in children with spherocytosis?
Children with moderate or severe forms of spherocytosis may be considered for splenectomy because of ongoing transfusion requirements, lethargy, jaundice, or discomfort from a massively enlarged spleen.
What are the advantages and disadvantages of partial splenectomy for
children with spherocytosis? [3]
Partial splenectomy, removing approximately 80% of the spleen, has been shown to be very effective in treating the anemia, jaundice and symptoms in children with spherocytosis, while theoretically decreasing the long-term risks of post-splenectomy sepsis and thrombosis.
The operation can be done laparoscopically, but is associated with a higher perioperative transfusion requirement, more pain, and a longer hospital stay than laparoscopic total splenectomy.
There is also a 10–15% risk of regrowth of the splenic remnant with recurrent symptoms and need for a completion splenectomy in the future.
What are the perioperative considerations when doing a splenectomy for a child with spherocytosis?
Most children with spherocytosis are otherwise healthy and can tolerate splenectomy well.
Almost half of patients with spherocytosis will develop gallstones; if they are symptomatic the gallbladder should be removed at the time of splenectomy.
There is controversy about whether asymptomatic gallstones should be removed at the time of splenectomy.
How should splenic cysts be managed?
Splenic cysts are usually congenital and have an epithelial lining.
These must be differentiated from echinococcal cysts, which should be removed, and liquification of a post-traumatic splenic hematoma, which will usually resolve over time.
Symptomatic epithelial cysts should be removed by partial splenectomy if possible, or total splenectomy if partial splenectomy is not technically feasible.
Asymptomatic epithelial cysts can be managed expectantly with serial imaging, but should be removed if they become symptomatic, or if they enlarge beyond 5 cm in diameter.
Techniques such as unroofing or marsupialization, although less invasive, are associated with a very high incidence of recurrence.
How should solid splenic masses be managed?
Solid splenic masses are rare, and usually represent benign lesions such as hemangioma or hamartoma.
These can be managed expectantly if they are asymptomatic, but excision with partial or total splenectomy should be considered if they become symptomatic or enlarge under observation.