In a recent large series evaluating reasons for splenectomy from tertiary institutions, the single indication for splenectomy was as an incidental procedure on operations on an adjacent organ. In these situations the spleen needs to be removed either for completeness of resection or because of division of the splenic vasculature. The actual primary treatments of those various disease entities in adjacent organs are subjects of multiple other chapters within this textbook, but a few comments need to be made regarding the reasons for splenectomy and whether splenic preservation procedures are possible.
One common indication for an incidental splenectomy is to remove tumors located in the distal pancreas. For decades, it was standard practice to remove the spleen when removing the body of the pancreas because the splenic vein is intimately associated with the distal pancreas. Because of the interest in splenic preservation due to the incidence of post-splenectomy infection, operations have been developed to remove the distal pancreas without removing the spleen. A second spleen-preserving pancreatectomy involves ligation of the splenic artery but preservation of short gastric vessels, utilizing those vessels as collateral inflow and outflow to maintain splenic viability. Removal of the distal pancreas with splenic preservation has also been recently reported as a laparoscopic procedure. For patients with tumors that mandate removal of the lymph nodes of the splenic hilum or with direct association of the tumor with splenic parenchyma, certainly it is more appropriate to do an operation based on neoplastic principles and perform a distal pancreatectomy. In other indications, if the anatomy is appropriate and the completeness of tumor resection is not compromised, splenic preservation is certainly possible.
Additional procedures in which it is common to perform a splenectomy include proximal gastric cancers. The importance of complete nodal dissection in long-term results in gastric resections has been debated for several decades. Level X lymph nodes are located in the splenic hilum, for 20–25% of proximal gastric cancers these nodes will have metastatic cancer mandating removal. Other tumors of the left upper quadrant and retroperitoneum may require splenectomy, including large renal cell carcinomas, left adrenal tumors, and retroperitoneal sarcomas that may infiltrate upward into the spleen. Although the asplenic state does make patients susceptible to infections (see Hyposplenism above), the spleen should be viewed as an expendable organ if necessary to accomplish complete resection of malignancies, and there should be no hesitation to remove the spleen in these situations to do an appropriate cancer operation.