Laparoscopic partial splenectomy in pediatric patients

Children with hematological disease ,which can have beneficial from a partial and/or total splenectomy, may be divided into three major groups. The first group includes the congenital hemolytic anemias in which the spherocytosis plays a significant role. The second group concerns the hemoglobinopathies especially thalassemia major and sickle cell disease (SCD), and the third the acquired immune-hematological disorders such as autoimmune hemolytic anemia and thrombocytopenic purpura. Taking into account the focus of this meeting, the partial splenectomy, it seems appropriate to underline the primary physiological rules of the spleen as an organ of the reticuloendothelial system: the filter function, the hemocatheresis and the bacteria phagocytosis. This last activity, which is part of the immunological function, regards the antigen specific immune response to the production of opsonine, that allows phagocytosis of polysaccharidic bacteria, the main source of sepsis for splenectomized patients. Total splenectomy exposes the patients to a higher risk of sepsis as well the age: children with an age less than five years-old have a 10 % risk of serious infections compared to 1-2% of an adult. We know from the experience that the underlying disease, such as thalassemia, can increases this risk up to a maximum risk of 1,000 times higher than the risk of 50 of post-trauma splenectomised patient. Looking over hematological indications for splenectomy, these have the main objective to remove the hemocatheresis function of the spleen. The main question is whether the partial splenectomy can preserve the immune function abolishing that of hemocatheresis. A removal of 75% of the splenic volume allows to maintain an immunological response to the pneumococcal stimulus. Hematological and immunological studies have shown that in the patients where partial splenectomy have been performed, the production of immunoglobulins and lymphocytes is maintained with good results. Even in experimental models, when the 75% of the weight of the spleen is removed, they have a preservation of the reticulo-endothelial function, as well as the index of phagocytosis in response to the pneumococcal infection. This feature is not present in the experimental model of auto-transplant splenic tissue due to the vascular modifications that does not allow to preserve the immunological function. Going back to hemocatheresis, we know that an indication to partial splenectomy is spherocytosis, which we classify into different levels of severity according to hemoglobin, reticulocyte and bilirubin values. The splenectomy is reserved for severe patients, which account for approximately 10-15% of all forms of spherocytosis but the objective is to postpone at least till the age of 5-6 years the timing of the surgery. In the long term follow-up of these patients, Hb values remain stable over time, as well as the reticulocyte count, although the hemolysis is not entirely abolished. If we look in detail to the splenic remnant, we may observe a recurrence of hypersplenism, that still tends to increase over the years, although this does not appear to affect the hematologic parameters of these patients; once again the growth of the spleen, accompanied by a restructuring of the parenchyma and vascular flow seems not to have a significative influence in these patients. Comparing papers on spherocytosis, the risk of recurrence of hypersplenism is also reported with a small number of patients requiring a total splenectomy. This procedure has been performed with good results also in patient with thalassemia major, although some Authors highlight that this procedure might have only a temporary effect, due to the presence of the residual splenic tissue that can grow in the following years; but at the mean time, this decision could be considered especially at a young age when these children are more sensitive to the infections of capsular bacteria. Considering sickle cell disease and guidelines of the onco-hematology pediatric community, the level of evidence, as well as the indication for the surgery becomes more restrictive; the partial removal of the spleen provides an efficient volume reduction, the need for transfusions and reduces the risk of splenic sequestration. In these patients the clinical picture is more complex as sickle cell disease involves a risk of having splenic infarction; furthermore, despite an appropriate splenic volume we have kids with reduced or functional asplenia where the immunological function is compromised. A report comparing the partial splenectomy with total laparoscopic to open surgery, shows that there are many, non randomized, prospective studies with heterogeneous data; the hematologic outcome has been analysed showing comparable results with partial and total splenectomy. With regard to the immunological function, the partial splenectomy appears to preserve the activity of phagocytosis. Significative differences were not observed between the open and the laparoscopic approach. In the last group of acquired immunological splenic diseases, the development of immunosuppressive therapies has reduced the indications to the splenectomy. In conclusion, we have still some open questions: partial splenectomy has always an indication or conversely, we must observe some criteria such as a younger age of 5-6 years? Some authors have suggested to reserve this approach to patients that for geographical or logistical reasons do not have a transfusion support and / or a poor antibiotic prophylaxis compliance. A further question to be considered is: the partial splenectomy, preserving the hematological function, could avoid in these patients, the antibiotic prophylaxis and pre-splenectomy vaccinations? Based on the American group’ experience, however, antibiotic prophylaxis is recommended for at least one year and still are carried out vaccinations, doubting the long-term effect of the partial splenectomy.