Splenic regeneration following splenectomy and impact on sepsis: a clinical review

Thoracic splenosis: an important consideration in oncology patients

SummarySplenosis is the implantation of ectopic splenic tissue after splenic injury or splenectomy. Signs and symptoms of splenosis vary based on anatomic location; however, it remains asymptomatic in many cases. On radiographic imaging, splenosis often appears as a soft tissue mass and can be diagnosed using heat-damaged red blood cell scintigraphy, a non-invasive imaging modality. Radiographic findings of splenosis on imaging may be suspicious for metastatic disease in patients with known solid organ tumours. It is important to have a high degree of suspicion for splenosis with known history of splenic trauma or splenectomy in order to avoid invasive procedures and guide appropriate management.

Long-term Results of Splenectomy in Transfusion-dependent Thalassemia

Splenectomy is indicated in transfusion-dependent thalassemia (TDT) only in certain situations. This study aimed to present the effectiveness, complications, and long-term follow-up results of splenectomy in children with TDT. We performed a 30-year single-institution analysis of cases of splenectomy for TDT between 1987 and 2017 and their follow-up until 2021. A total of 39 children (female/male: 24/15) were included. The mean age at splenectomy was 11.2±3.2 years, and their mean follow-up duration after splenectomy was 21.5±6.4 years. Response was defined according to the patient's annual transfusion requirement in the first year postsplenectomy and on the last follow-up year. Complete response was not seen in any of the cases; partial response was observed in 32.3% and no response in 67.6%. Thrombocytosis was seen in 87% of the patients. The platelet counts of 7 (17.9%) patients were >1000 (10 9 /L), and aspirin prophylaxis was given to 22 (56.4%) patients. Complications were thrombosis in 2 (5.1%) patients, infections in 11 (28.2%) patients, and pulmonary hypertension in 4 (10.2%) patients. Our study showed that after splenectomy, the need for transfusion only partially decreased in a small number of TDT patients. We think splenectomy can be delayed with appropriate chelation therapy up to higher annual transfusion requirement values.

Spleen: Reparative Regeneration and Influence on Liver

This review considers experimental findings on splenic repair, obtained in two types of small animal (mouse, rat, and rabbit) models: splenic resections and autologous transplantations of splenic tissue. Resection experiments indicate that the spleen is able to regenerate, though not necessarily to the initial volume. The recovery lasts one month and preserves the architecture, albeit with an increase in the relative volume of lymphoid follicles. The renovated tissues, however, exhibit skewed functional profiles; notably, the decreased production of antibodies and the low cytotoxic activity of T cells, consistent with the decline of T-dependent zones and prolonged reduction in T cell numbers. Species-specific differences are evident as well, with the post-repair organ mass deficiency most pronounced in rabbit models. Autotransplantations of splenic material are of particular clinical interest, as the procedure can possibly mitigate the development of post-splenectomy syndrome. Under these conditions, regeneration lasts 1-2 months, depending on the species. The transplants effectively destroy senescent erythrocytes, assist in microbial clearance, and produce antibodies, thus averting sepsis and bacterial pneumonia. Meanwhile, cellular sources of splenic recovery in such models remain obscure, as well as the time required for T and B cell number reconstitution.

Splenic auto-transplantation after splenectomy for trauma: evaluation of a new technique

BACKGROUND

Splenic autotransplantation is a promising method to recover splenic functions after traumatic splenectomy. However, it is associated with several postoperative complications, such as subphrenic abscess, intestinal obstruction and torsion of the omentum with necrosis of the implanted splenic tissues. Therefore, the aim of this study is to evaluate a new splenic autotransplantation technique that could overcome those complications.

MATERIALS AND METHODS

A single segment of the spleen was implanted inside a pedunculated omental pouch and fixed in the native site of the spleen in 15 patients who underwent splenectomy for abdominal trauma. This group of patients was compared with the next 17 patients who underwent splenectomy alone. Additionally, splenic functions of the patient and control groups were evaluated 3 months using peripheral blood smear [the presence of Howell-Jolly (HJ) bodies] and abdominal contrast-enhanced computed tomography (CECT).

RESULTS

All patients who underwent splenic autotransplantation showed evidence of a well-vascularised splenic tissue on CECT and normal peripheral blood smear without HJ bodies 3 months postoperatively. No postoperative complications related to splenic autotransplantation were observed, and platelet count after 3 months was significantly higher in patients who underwent splenectomy only (p = 0.04).

CONCLUSIONS

Splenic autotransplantation using the aforementioned technique could restore splenic functions with minimum postoperative complications related to the procedure.

Role of Partial Splenectomy in Hematologic Childhood Disorders

The spleen is a secondary lymphoid organ that belongs to the reticular-endothelial system, directly connected to blood circulation. The spleen is greatly involved in the immune response, especially against capsulated bacteria. Splenectomy plays a fundamental role in the treatment of numerous pediatric hematologic disorders. Taking into account all the possible complications (especially infections) linked to this procedure, alternatives to total splenectomy have been sought. Partial splenectomy has been proposed as a treatment that allows the reduction of infectious risk. This approach has proven safe and feasible in most patients, but multicentric and prospective studies are necessary to more accurately define the indications for performing partial splenectomy. However, vaccinations and antibiotic prophylaxis remain fundamental for preventing serious infections, even in the case of partial splenectomy. We review anatomical and functional properties of the spleen, with a focus on medical or surgical indications to splenectomy, aiming to give practical educational information to patients and their families after splenectomy. Furthermore, we discuss the feasibility of partial splenectomy in children with hematologic diseases who require splenectomy.

Prevalence and distribution of functional splenic tissue after splenectomy

BACKGROUND

Individuals splenectomised for trauma have lower infection rates than those splenectomised for other conditions. Residual functional splenic tissue (FST) after splenectomy may provide ongoing immunological protection.

AIMS

To quantify the prevalence and volume of residual FST post-splenectomy using standard testing.

METHODS

Splenectomised adults were recruited from the Spleen Australia clinical registry. Eligible individuals had been splenectomised at least 1 year prior to their visit and resided in Victoria. Splenic function was identified by evaluating Howell-Jolly bodies and IgM memory B cells. A 99m-Technetium-labelled, heat-denatured erythrocyte scintigraphic scan was performed if splenic function was detected.

RESULTS

Initially, 75 splenectomised individuals (all cause) were recruited, with a median of 58 years of age and who were splenectomised a median of 14 years previously. The most common indications for splenectomy were trauma (30.7%) and haematological disease (28.0%). Scintigraphy identified FST in nine individuals (12.0%). Eight had been splenectomised for trauma. In this cohort, 34.8% of individuals splenectomised for trauma had residual FST. To explore our findings further, 45 additional individuals were recruited, predominately individuals splenectomised for trauma. Twenty-five individuals completed assessments by December 2018. An additional 11 individuals had FST, of whom 9 had been splenectomised for trauma. Overall, we identified 20 individuals with residual FST. Volumes ranged from 2.2 to 216.0 cc. We saw individuals with accessory spleens and splenotic nodules and an individual with both. Seventeen individuals had been splenectomised for trauma.

CONCLUSIONS

Residual FST is commonly seen in individuals splenectomised for trauma. It can present in varying distributions and of varying volume. The clinical significance is unclear.

Case Report: Conservative Non-operative Management of a Neonate With Torted Wandering Spleen

BACKGROUND

The management of wandering spleen (WS) with torsion, a rare pathological condition, is currently unclear. Most patients with this disorder are treated with surgical interventions, such as splenectomy or splenopexy.

CASE PRESENTATION

A newborn female presented with low hemoglobin (10.8 mg/L) and high total serum bilirubin (193 μmol/L) at 3 h of life. A palpable mass was observed during her physical examination, and a magnetic resonance imaging scan of the abdomen confirmed the presence of an infarcted WS with torsion. Upon conservative management with oral antibiotic prophylaxis, careful observation, and repeated follow-ups, the infant remained clinically stable. At 2 years of age, she had normal complete blood count, and a repeat technetium study revealed two splenunculi/splenules in the splenic bed.

CONCLUSION

Most patients with WS are treated surgically with splenectomy or splenopexy. Non-operative management may be a feasible treatment option in select cases with infarcted WS and may allow the natural process of autosplenectomy to occur.

Mesentery - a 'New' organ

The mesentery is the organ in which all abdominal digestive organs develop, and which maintains these in systemic continuity in adulthood. Interest in the mesentery was rekindled by advancements of Heald and Hohenberger in colorectal surgery. Conventional descriptions hold there are multiple mesenteries centrally connected to the posterior midline. Recent advances first demonstrated that, distal to the duodenojejunal flexure, the mesentery is a continuous collection of tissues. This observation explained how the small and large intestines are centrally connected, and the anatomy of the associated peritoneal landscape. In turn it prompted recategorisation of the mesentery as an organ. Subsequent work demonstrated the mesentery remains continuous throughout development, and that abdominal digestive organs (i.e. liver, spleen, intestine and pancreas) develop either on, or in it. This relationship is retained into adulthood when abdominal digestive organs are directly connected to the mesentery (i.e. they are 'mesenteric' in embryological origin and anatomical position). Recognition of mesenteric continuity identified the mesenteric model of abdominal anatomy according to which all abdominal abdomino-pelvic organs are organised into either a mesenteric or a non-mesenteric domain. This model explains the positional anatomy of all abdominal digestive organs, and associated vasculature. Moreover, it explains the peritoneal landscape and enables differentiation of peritoneum from the mesentery. Increased scientific focus on the mesentery has identified multiple vital or specialised functions. These vary across time and in anatomical location. The following review demonstrates how recent advances related to the mesentery are re-orientating the study of human biology in general and, by extension, clinical practice.

Post Splenectomy Outcome in β-Thalassemia

OBJECTIVES

To evaluate changes in annual blood transfusion requirements and complications after splenectomy in patients with β-thalassemia.

METHODS

Forty post-splenectomy β-thalassemic patients aged 8-33 y, receiving regular blood transfusions and chelation therapy were included and non transfusion dependant patients were excluded from this retrospective cross-sectional study. Details about their surgery, transfusion requirements, and platelet levels were recorded on a standard proforma. All patients underwent a B-mode and color-coded duplex sonography of the hepatoportal system during the study period.

RESULTS

The average ferritin level in the year prior to the study was 4432 mcg/L (range 480-12,200 mcg/L). The annual blood transfusion requirement in the first year and 5 y post splenectomy [mean ± SD (138.41 ± 90.38 ml/kg/y); (116 ± 41.44 ml/kg/y)] were significantly different from requirements before splenectomy [(mean ± SD) 294.85 ± 226 ml/kg/y; p value <0.001]. There was a significant rise in platelet counts within 24 h post splenectomy with a mean rise of 4,51,000/mm(3) (p value < 0.001). During the follow up period, infections were noted in 50 % of patients, with malaria (18.75 %) being the most common. Doppler study of the portal system in one case showed portal vein thrombosis.

CONCLUSIONS

A significant sustained fall in annual blood transfusion requirement and a rise in platelet counts occurred post-splenectomy. Increase in annual blood transfusion requirement should be investigated to find the cause.