Asplenia and Polysplenia

Asplenia is often noted with complex congenital heart disease as well as bilateral ‘right-sidedness’ such as bilateral three-lobed lungs and right-sided stomach and central liver.¹⁰ Intestinal malrotation has also been observed with asplenia.¹¹ These infants are at risk for overwhelming infection and should receive antibiotics for prophylaxis.

Polysplenia usually consists of a cluster of very small splenic masses and is often found with biliary atresia. Other associated conditions include a preduodenal portal vein, situs inversus, malrotation, and cardiac defects.¹⁰ These children have adequate splenic immune function.

Wandering Spleen

This condition is characterized by a lack of ligamentous attachments to the diaphragm, colon, and retroperitoneum, resulting in a mobile spleen. This is likely due to failure of development of the splenic ligaments from the dorsal mesentery.¹² Children can present with an abdominal mass and episodic pain, but also with torsion and infarction.^13,14 Pancreatitis has also been noted as a presenting sign.¹⁵ Splenopexy is the preferred method of treatment and can be performed with placement of the spleen into a mesh basket, suture splenopexy, colonic displacement with gastropexy, placement in an omental basket, or placement in an extraperitoneal pocket.^16–20 The laparoscopic approach is the preferred technique, and the use of an absorbable or nonabsorbable mesh with fixation in the left upper quadrant is demonstrated in Figure 47-1.^21,22 Placement of the spleen in an extraperitoneal pocket is seen in Figure 47-2. Torsion with infarction requires splenectomy. Cases of chronic torsion have also been reported with massive splenomegaly which may necessitate splenectomy.²³

Accessory Spleens

Accessory spleens have been noted in 15–30% of children, with a large series noting a 19% rate.²¹ Accessory spleens likely originate from mesenchymal remnants that fail to fuse with the main splenic mass, with most (75%) located near the splenic hilum (Fig. 47-3). Other locations that must be evaluated during surgery include the lesser sac along the splenic vessels, omentum, and retroperitoneum. Eighty-six per cent of accessory spleens are single, 11% have two, and 3% have three or more.^24,25 A missed accessory spleen at the time of planned total splenectomy can lead to recurrence of the primary disease process, which in cases of immune thrombocytopenic purpura (ITP) is early and with hereditary spherocytosis (HS) is later.^26–28

Splenic Gonadal Fusion

This condition in which the left gonad and the spleen are attached is a result of early fusion between the two structures prior to descent of the testes.²⁹ The remnant can be a continuous band (see Fig 50-6) or discontinuous with splenic tissue attached to the gonad. A splenic remnant has also been noted in the left scrotum as an accessory splenic remnant type of abnormality.³⁰

Splenic Cysts

Cysts of the spleen are most frequently primary splenic cysts containing an epithelial lining and are also referred to as epithelial or epidermoid cysts (Fig. 47-4). Post-traumatic pseudocysts are occasionally seen. Inclusion of surface mesothelium into the splenic parenchyma is the most likely etiology of epithelial cysts. They may present with symptoms related to their size with gastric compression or pain, an abdominal mass, rupture, or infection with abscess.^31,32 Simple cysts less than 5 cm can be observed, but cysts that are enlarging, symptomatic, or larger than 5 cm require treatment. Most symptomatic cysts are larger than 8 cm.³¹ Percutaneous aspiration and sclerosis utilizing alcohol or other agents have been reported with variable success.^33,34

Marsupialization is commonly performed but has been associated with a high recurrence rate if an adequate amount of cyst wall is not removed (Fig. 47-5).³⁵ In addition, a high recurrence rate with laparoscopic partial excision has also been observed.^36,37 However, others have had good success with this technique, and many also recommend partial splenectomy associated with cyst resection.^38,39 Our group has reported good results with partial splenectomy, emphasizing resection of a margin of normal spleen so that the cut surfaces cannot oppose which might lead to recurrence.²¹ Other techniques involve lining the cyst with Surgicel (Ethicon, Inc., Somerville, NJ) and omentopexy.⁴⁰

Hereditary Spherocytosis

HS, an autosomal dominant condition, is the most common inherited red cell disorder among Northern European descendants, with approximately 25% of affected children representing new mutations. Defects in red cell proteins ankyrin or spectrin result in poorly deformable spherocytes. Most affected children have anemia, an elevated reticulocyte count, and a mild elevation in bilirubin concentration. The degree of hemolysis can vary, with some only having a mild anemia. Spherocytes on peripheral smear along with a positive osmotic fragility test confirms the diagnosis. Affected children may develop an aplastic crisis associated with parvovirus B19 infection with suppression of bone marrow red cell production and ongoing splenic red cell destruction.⁴¹ Splenectomy is usually performed for moderate-to-severe anemia. If possible, splenectomy is delayed until 5 to 6 years of age to decrease the likelihood of overwhelming postsplenectomy infection (OPSI). Splenomegaly is common in these patients. Gallstones are also often found, and an ultrasound evaluation of the gallbladder should be performed before splenectomy. The presence of gallstones in children undergoing splenectomy has been noted in 27% of those younger than age 10 years compared with 56% in children 10 years of age or older.²¹

Partial splenectomy is an attractive alternative to total splenectomy in an attempt to remove enough spleen to alleviate the anemia while preserving adequate spleen to prevent OPSI (Fig. 47-6). This may be particularly useful in young children requiring splenectomy, but the long-term results are not known.

Immune Thrombocytopenic Purpura

ITP occurs due to antiplatelet autoantibodies which subsequently are destroyed in the spleen. In most children, it is primary (idiopathic), whereas in some it may be secondary to lupus, human immunodeficiency virus, malignancy, or hepatitis C infection. Most children (80%) have acute ITP that resolves with simple observation or medical management. Most treatment plans target a decrease in platelet destruction. Management includes corticosteroids, which may have their effect by inhibiting the reticuloendothelial binding of platelet/antibody complexes; intravenous immunoglobulin (IVIG), which inhibits the Fc receptor binding of platelets by macrophages; or Rho(D) immunoglobulin in Rh-positive children, which bind red cells that then saturate the splenic receptors, allowing the platelets to avoid destruction.

Response to corticosteroids, IVIG, or both, have been thought to be excellent predictors of successful outcome with splenectomy.42,43 However, two recent studies have failed to confirm this prior assumption. In a study of 19 children, Wood et al. failed to identify a positive correlation between preoperative medical treatment and response to splenectomy. In fact, they found an inverse relationship between the preoperative steroid response and response to splenectomy, with all nonresponders to steroids being complete responders to splenectomy.⁴⁴ In a similar study from our institution, 31 of 37 (84%) children with ITP had complete response to splenectomy, and 6 (16%) had partial response.⁴⁵ Of the eight with no response to steroids, six had a complete response and two had a partial response to splenectomy which suggests that failure to respond to steroids should not preclude splenectomy as definitive therapy.

Some children with ITP fail to respond to medical treatment, whereas others develop relapse when the treatment is stopped. In some of these patients, further therapy may include rituximab, a monoclonal antibody against CD20-positive B-cells. This depletes the B-cells and is somewhat of a ‘medical splenectomy.’ Other treatment modalities include azathioprine, cyclophosphamide, danazol, and mycophenolate mofetil.⁴⁶ Platelet production may be decreased in ITP. Thus, the use of thrombopoietic agents has emerged⁴⁶ and successful therapy with agents such as romiplostim (AMG 531, Amgen Inc., Thousand Oaks, CA) has been reported.⁴⁷ A recent follow-up report in adults noted that those treated with romiplostim (by weekly continuous infusion) had a higher rate of platelet response and a lower incidence of splenectomy than those treated with standard medical therapy.⁴⁸

Children with thrombocytopenia for longer than six months are considered to have chronic ITP and are candidates for splenectomy. The response to splenectomy has been excellent in children who have responded to medical management. In adults, the response is not as high. Accessory spleens or residual splenic tissue has been identified in up to 50% of adult patients with ITP, thus emphasizing both the importance of accessory spleen detection at exploration as well as the need to avoid parenchymal disruption.²⁶

Sickle Cell Disease

Sickle cell disease (SCD) results from an amino acid substitution in the β-chain of normal hemoglobin A, which results in hemoglobin S. Children may be homozygous (SCD) or have less severe heterozygous types such as sickle-C or sickle-thalassemia. These red blood cells become rigid as they pass through the hypoxic environment of the spleen, leading to splenic sequestration. Although autoinfarction and atrophy lead to a functional asplenic state in most children, some develop symptomatic sequestration. If the sequestration is severe, these children develop anemia and splenomegaly with associated thrombocytopenia known as acute splenic sequestration crisis. Due to the associated morbidity and mortality, severe or recurrent episodes merit consideration for splenectomy.

A recent report of 53 children with SCD less than 4 years of age at the time of splenectomy found that 5.7% died during the 15 year study with one (1.8%) dying of OPSI.⁴⁹ The authors concluded that it is reasonable to perform a splenectomy around age 2 years if a child with SCD has had a serious episode of sequestration.

Thalassemia

The thalassemias are characterized by abnormal production of α-or β-chains of hemoglobin. Thalassemia major (β-thalassemia) is associated with the most severe clinical anemia among this group. Splenomegaly causes further red cell sequestration and need for transfusion. Total or partial splenectomy has been performed to decrease the need for transfusions in children with severe anemia.

Gaucher Disease

Gaucher disease is characterized by a deficiency of the enzyme β-glucocerebrosidase, resulting in excessive glucocerebroside in the macrophages of the spleen, liver, bone marrow, and lungs. Splenomegaly may be severe, and both partial and total splenectomy have been utilized to alleviate the symptomatic hypersplenism and to decrease destruction of the red blood cells, leukocytes, and platelets.⁵⁰ However, massive bleeding and death has been reported several months postoperatively in a child with Gaucher disease who underwent partial splenectomy.⁵¹

Open Splenectomy

The open technique through a left upper quadrant incision is usually reserved for massive splenomegaly. The initial division of the splenorenal, splenocolic, and splenophrenic ligaments allows the spleen to be mobilized from the left upper quadrant and out of the abdominal cavity. The short gastric vessels are divided initially, followed by the hilar vessels. A careful search must be undertaken for accessory spleens. A lateral muscle-splitting approach has been reported with a 2.7-day length of stay which is comparable to some early laparoscopic series but longer than more recent series.21,52,53

Laparoscopic Splenectomy

Laparoscopic splenectomy has evolved over the past 15 to 20 years to become the preferred approach for splenectomy.3,4 Less pain, shorter hospitalization, faster return to regular activities, and smaller scars are the main advantages over open splenectomy. However, it is associated with a longer operative time and can be difficult in patients with splenomegaly. The main technical advances have been the result of smaller instrumentation and advanced energy sources such as the Harmonic Scalpel (Ethicon Endosurgery Inc, Cincinnati, OH) and Ligasure (Valley Lab, Tyco Healthcare Group, Boulder, CO). At our institution, we primarily utilize the Ligasure because it allows division of vessels up to 7 mm.

The most significant initial concern for the laparoscopic approach was related to accessory spleen detection. However, in adult studies and comparison pediatric series, similar rates of accessory spleen detection at laparoscopic and open splenectomy have been noted.26,27,53–56 For the laparoscopic operation, most surgeons utilize a lateral approach with slight elevation of the left flank. One technique to improve the ease of port placement is to have the patient’s left side initially elevated approximately 45° rather than the true lateral position. The operating table is then tilted to the patient’s left to achieve a flat position for the port placement and then is tilted to the patient’s right to achieve a lateral position for the procedure (Fig. 47-7). The surgeon and assistant stand on the patient’s right. In young children and patients with small spleens, the upper midline instruments (3 mm) can be inserted without cannulas because these instruments are not removed during the procedure (Fig. 47-8). The first assistant holds the two upper midline instruments to provide elevation of the spleen and traction on surrounding tissues. The surgeon holds the camera (5 mm, 30–45° telescope) in the left hand and the energy source in the right hand.