Some possibilities of representing microcirculation in human spleen

Erythrocyte flow through the interendothelial slits of the splenic venous sinus

The flow patterns of red blood cells through the spleen are intimately linked to clearance of senescent RBCs, with clearance principally occurring within the open flow through the red pulp and slits of the venous sinus system that exists in humans, rats, and dogs. Passage through interendothelial slits (IESs) of the sinus has been shown by MacDonald et al. (Microvasc Res 33:118-134, 1987) to be mediated by the caliber, i.e., slit opening width, of these slits. IES caliber within a given slit of a given sinus section has been shown to operate in an asynchronous manner. Here, we describe a model and simulation results that demonstrate how the supporting forces exerted on the sinus by the reticular meshwork of the red pulp, combined with asymmetrical contractility of stress fibers within the endothelial cells comprising the sinus, describe this vital and intriguing behavior. These results shed light on the function of the sinus slits in species such as humans, rats, and dogs that possess sinusoidal sinuses. Instead of assuming a passive mechanical filtering mechanism of the IESs, our proposed model provides a mechanically consistent explanation for the dynamically modulated IES opening/filtering mechanism observed in vivo. The overall perspective provided is also consistent with the view that IES passage serves as a self-protective mechanism in RBC vesiculation and inclusion removal.

First experience with single incision laparoscopic surgery in Slovakia: concomitant cholecystectomy and splenectomy in an 11-year-old girl with hereditary spherocytosis

AIMS

Hereditary spherocytosis is an autosomal dominant inheritance disorder of the red blood cell membrane characterized by the presence of spherical-shaped erythrocytes (spherocytes) in the peripheral blood. The main clinical features include haemolytic anemia, variable jaundice, splenomegaly and cholelithiasis caused by hyperbilirubinemia from erythrocyte hemolysis. Splenectomy does not solve the congenital genetic defect but it stops pathological hemolysis in the enlarged spleen. If gallstones are present, it is appropriate to perform cholecystectomy at the time of splenectomy, although the patient has symptoms of gall bladder disease. We present the case of single incision laparoscopic surgical (SILS) concomitant splenectomy and cholecystectomy performed with conventional laparoscopic instruments in an 11-year-old girl with the diagnosis of hereditary spherocytosis.

METHODS

A 2-3 cm umbilical incision was used for the placement of two 5 mm trocars and one 10 mm flexible videoscope. Conventional laparoscopic dissector, grasper, Ligasure, Harmonic Ace and hemoclips were the main tools during surgical procedure. We prefer Single Incision Laparoscopic Surgery Foam Port (Covidien) as the single umbilical device for introduction into the abdominal cavity. First, we performed cholecystectomy, then the gallbladder was put aside over the liver and after that we peformed splenectomy. To remove the detached spleen and gallbladder, a nylon extraction bag is introduced through one of the port sites. The spleen is than morcellated in the bag with forceps and removed in fragments. After that we removed them and the umbilical fascial incision was closed.

RESULT

Splenectomy is the only effective therapy for this disorder and often it is performed in combination with cholecystectomy. Conventional surgery requires a wide upper abdominal incision for correct exposure of the gallbladder and spleen. Our experience shows that SILS splenectomy and cholecystectomy is feasible even in young children and despite the small number of cases in the world, we consider the combined laparoscopic approach safe and effective for the treatment of hereditary spherocytosis.

CONCLUSION

According to actually published guidelines, the laparoscopic approach to concomitant splenectomy and cholecystectomy is recommended, but it depends on the availability of appropriately trained surgeons and suitable equipment.