Comparative effectiveness of angioembolization versus open surgery in patients with blunt splenic injury.

The effectiveness and safety of transcatheter splenic artery embolization (SAE) compared to those of open surgery in patients with blunt splenic injury (BSI) remain unclear. This retrospective cohort-matched study utilized data from the Japan Trauma Data Bank recorded between 2004 and 2019. Patients with BSI who underwent SAE or open surgery were selected. A propensity score matching analysis was used to balance the baseline covariates and compare outcomes, including all-cause in-hospital mortality and spleen salvage. From 361,706 patients recorded in the data source, this study included 2,192 patients with BSI who underwent SAE or open surgery. A propensity score matching analysis was used to extract 377 matched pairs of patients. The in-hospital mortality rates (SAE, 11.6% vs. open surgery, 11.2%, adjusted relative risk (aRR): 0.64; 95% confidence interval [CI]: 0.38-1.09, p = 0.10) were similar in both the groups. However, spleen salvage was significantly less achieved in the open surgery group than in the SAE group (SAE, 87.1% vs. open surgery, 32.1%; aRR: 2.84, 95%CI: 2.29-3.51, p < 0.001). Survival rates did not significantly differ between BSI patients undergoing SAE and those undergoing open surgery. Nonetheless, SAE was notably associated with a higher likelihood of successful spleen salvage.

Long-term outcomes after spleen-preserving distal pancreatectomy with splenic vessels preservation or resection: A nationwide survey of the Japanese Society of Pancreatic Surgery.

BACKGROUND: Spleen preserving distal pancreatectomy is achieved by either splenic vessel resection or splenic vessel preservation. However, the long-term outcomes of spleen-preserving distal pancreatectomy with splenic vessel resection and spleen-preserving distal pancreatectomy with splenic vessel preservation are not well known. This study aimed to evaluate the long-term outcomes of spleen-preserving distal pancreatectomy with splenic vessel resection and spleen-preserving distal pancreatectomy with splenic vessel preservation. METHODS: The study included a total of 335 patients who underwent spleen-preserving distal pancreatectomy during the study period and underwent computed tomography or magnetic resonance imaging 3 and 5 years after surgery in the Japan Society of Pancreatic Surgery member institutions. We evaluated the diameter of the perigastric and gastric submucosal veins, patency of the splenic vessels, and splenic infarction. Preoperative backgrounds and short- and long-term outcomes were compared between the 2 groups. RESULTS: Forty-four (13.1%) and 291 (86.9%) patients underwent spleen-preserving distal pancreatectomy with splenic vessel resection and spleen-preserving distal pancreatectomy with splenic vessel preservation, respectively. There were no significant differences in short-term outcomes between the 2 groups. Regarding long-term outcomes, the prevalence of perigastric varices was higher (P = .006), and platelet count was lower (P = .037) in the spleen-preserving distal pancreatectomy with splenic vessel resection group. However, other complications, such as gastric submucosal varices, postoperative splenic infarction, gastrointestinal bleeding, reoperation, postoperative splenectomy, and other hematologic parameters, were not significantly different between the 2 groups 5 years after surgery. In terms of the patency of splenic vessels in spleen preserving distal pancreatectomy with splenic vessel preservation cases, partial or complete occlusion of the splenic artery and vein was observed 5 years after surgery in 19 (6.5%) and 55 (18.9%) patients, respectively. CONCLUSION: Perigastric varices and thrombocytopenia were observed more in spleen-preserving distal pancreatectomy with splenic vessel resection, yet late clinical events such as gastrointestinal bleeding and splenic infarction are acceptable for spleen-preserving distal pancreatectomy with splenic vessel preservation.

CT perfusion imaging of the liver and the spleen can identify severe portal hypertension.

PURPOSE: To determine if hepatic and splenic perfusion parameters are useful in identifying severe portal hypertension (SPH). METHODS: The study enrolled 52 patients who underwent perfusion CT scan within one week before the hepatic venous pressure gradient (HVPG) measurement. A commercial software package was used for post-processing to generate hepatic and splenic perfusion parameters. Correlations were assessed using Pearson and Spearman rank correlation coefficients. Logistic regression was used to screen predictive parameters of SPH. The cut-off values of parameters for severe portal hypertension were calculated, as well as the sensitivity and specificity. RESULTS: There was a significant difference between SPH and non-severe portal hypertension (NSPH) in blood volume of liver (BVLiver), hepatic arterial fraction (HAF), hepatic arterial perfusion (HAP), portal venous perfusion (PVP), mean slope of increase in spleen (MSISpleen), BVSpleen, blood flow of spleen (BFSpleen), BVSpleen/Liver, and BVSpleen/Liver(P) (p < 0.05). The Spearman correlation coefficient was - 0.541 (p < 0.001) between BVSpleen/Live and HVPG and - 0.568 (p < 0.001) between BVSpleen/Liver(P) and HVPG. Using a BVSpleen/Liver value of 0.780 or BVSpleen/Liver(P) value of 1.061 as the cut-off value for the detection of SPH, the sensitivity and specificity were 94.7% and 72.7%, 100%, and 63.6% respectively. CONCLUSION: There was a moderate correlation between CT perfusion parameters BVSpleen/Liver, BVSpleen/Liver(P), and HVPG, which may be used to detect severe portal hypertension.

The use and timing of angioembolization in pediatric blunt liver and spleen injury.

BACKGROUND: Nonoperative management (NOM) is the standard of care for the management of blunt liver and spleen injuries (BLSI) in the stable pediatric patient. Angiography with embolization (AE) is used as an adjunctive therapy in the management of adult BLSI patients, but it is rarely used in the pediatric population. In this planned secondary analysis, we describe the current utilization patterns of AE in the management of pediatric BLSI. METHODS: After obtaining IRB approval at each center, cohort data was collected prospectively for children admitted with BLSI confirmed on CT at 10 Level I pediatric trauma centers (PTCs) throughout the United States from April 2013 to January 2016. All patients who underwent angiography with or without embolization for a BLSI were included in this analysis. Data collected included patient demographics, injury details, organ injured and grade of injury, CT finding specifics such as contrast blush, complications, failure of NOM, time to angiography and techniques for embolization. RESULTS: Data were collected for 1004 pediatric patients treated for BLSI over the study period, 30 (3.0%) of which underwent angiography with or without embolization for BLSI. Ten of the patients who underwent angiography for BLSI failed NOM. For patients with embolized splenic injuries, splenic salvage was 100%. Four of the nine patients undergoing embolization of the liver ultimately required an operative intervention, but only one patient required hepatorrhaphy and no patient required hepatectomy after AE. Few angiography studies were obtained early during hospitalization for BLSI, with only one patient undergoing angiography within 1 hour of arrival at the PTC, and 7 within 3 hours. CONCLUSION: Angioembolization is rarely used in the management of BLSI in pediatric trauma patients with blunt abdominal trauma and is generally used in a delayed fashion. However, when implemented, angioembolization is associated with 100% splenic salvage for splenic injuries. LEVEL OF EVIDENCE: Therapeutic/Care Management; Level IV.

Laparoscopic partial splenectomy in distal pancreatectomy may preserve splenic function.

INTRODUCTION: Splenectomy is known to carry a risk of infection with encapsulated organisms and associated sepsis. Current Australian guidelines recommend intensive vaccination schedules and long-term antibiotic therapy. We postulate that in some clinical scenarios where distal pancreatectomy (DP) and splenectomy is being performed, a partial splenectomy is feasible. This may preserve splenic function and help retain immunocompetence. METHODS: Five patients underwent laparoscopic distal pancreatectomy with partial splenectomy (LDPPS). The DP is performed with proximal division and resection of the splenic artery and vein. The inferior portion of the spleen is removed en bloc with the distal pancreas with ligasure and linear cutting staplers. The line of demarcation on the spleen after the division of the splenic artery identifies the portion supplied by the short gastric vessels. Temporary clamping of the short gastrics during splenic parenchymal transection reduces blood loss. All operations were completed laparoscopically and within 4 h. RESULTS: The pathology of resected lesions includes a serous cystadenoma, a pseudocyst, an IPMN and two small medial pancreatic ductal adenocarcinomas. The benign lesions involved splenic vessels at the hilum, making Kimura or Warshaw procedures untenable. No patient required blood transfusion. One patient suffered a postoperative collection consistent with postoperative pancreatic fistula requiring a drain for 10 days. Follow-up ranged from 6 to 24 months. Following surgery, all patients had a perfused splenic remnant on imaging and benign blood films, which suggests retained splenic function. CONCLUSION: Preserving some spleen when performing distal pancreatectomy may provide long-term benefits for patients.

Laparoscopic spleen-preserving distal pancreatectomy: A novel technique with splenic artery resection and splenic vein preservation.

INTRODUCTION: Laparoscopic spleen-preserving distal pancreatectomy (LSDP) is widely performed to treat benign and low-grade malignant diseases. Although preservation of splenic vessels may be desirable considering the risk of postoperative complications, it is sometimes difficult due to tumor size, inflammation, and proximity of the tumor and splenic vessels. Herein, we present the first case of LSDP with splenic artery resection and splenic vein preservation. MATERIALS AND SURGICAL TECHNIQUE: A 40-year-old woman with a pancreatic tumor was referred to our hospital. Contrast-enhanced computed tomography (CT) revealed a tumor in the pancreatic tail that was in contact with the splenic artery and distant from the splenic vein. The splenic artery and vein were separated from the pancreas near the dissection line. The splenic artery was resected after pancreatic dissection using a linear stapler. After the pancreatic tail was separated from the splenic hilum while preserving the splenic vein, the distal side of the splenic artery was resected, and the specimen was removed. The postoperative course was uneventful and the patient was discharged on postoperative Day 9. Four months after surgery, postoperative follow-up CT findings showed neither splenic infarction nor gastric varices. DISCUSSION: This technique is an alternative method of splenic preservation when there is no attachment of the tumor to the splenic vein or uncontrolled expected bleeding of the splenic artery using the Kimura technique.

Splenic artery embolisation for splenic injury during colonoscopy: A systematic review.

BACKGROUND: Splenic injury due to colonoscopy is rare, but has high mortality. While historically treated conservatively for low-grade injuries or with splenectomy for high-grade injuries, splenic artery embolisation is increasingly utilised, reflecting modern treatment guidelines for external blunt trauma. This systematic review evaluates outcomes of published cases of splenic injury due to colonoscopy treated with splenic artery embolisation. METHODS: A systematic review was performed of published articles concerning splenic injury during colonoscopy treated primarily with splenic artery embolisation, splenectomy, or splenorrhaphy from 1977 to 2022. Datapoints included demographics, past surgical history, indication for colonoscopy, delay to diagnosis, treatment, grade of injury, splenic artery embolisation location, splenic preservation (salvage), and mortality. RESULTS: The 30 patients treated with splenic artery embolisation were of mean age 65 (SD 9) years and 67% female, with 83% avoiding splenectomy and 6.7% mortality. Splenic artery embolisation was proximal to the splenic hilum in 81%. The 163 patients treated with splenectomy were of mean age 65 (SD 11) years and 66% female, with 5.5% mortality. Three patients treated with splenorrhaphy of median age 60 (range 59-70) years all avoided splenectomy with no mortality. There was no difference in mortality between splenic artery embolisation and splenectomy cohorts (p = 0.81). CONCLUSIONS: Splenic artery embolisation is an effective treatment option in splenic injury due to colonoscopy. Given the known benefits of splenic salvage compared to splenectomy, including preserved immune function against encapsulated organisms, low cost, and shorter hospital length of stay, embolisation should be incorporated into treatment pathways for splenic injury due to colonoscopy in suitable patients.

Morphological, histological, and histochemical study of the adult golden hamster (Mesocricetus auratus) spleen.

Background: The golden hamster is a choice model for investigating many visceral and splenic infections and neoplastic and retrospective lesions. Aim: To study hamsters' spleen's morphological, histological, and histochemical structure. Methods: Samples were collected from eight healthy adult golden hamsters and then fixed with 10% buffered formalin. Later, samples were processed, sectioned, and stained with Hematoxylin and Eosin as well as Masson's Trichrome stain. Other slides were further stained with Periodic Acid Schiff and Alcian blue 2.5 stain (PAS) for histochemical evolution; the gross measurement was performed for the splenic length, width, and thickness, while the histological measures included the splenic capsular and trabecula thickness, diameter of white pulp follicles, splenic sinusoids and central arteries and proportion of white and red pulps. Results: The macroscopic findings revealed that the spleen was red-brown lanciform on the left side of the dorsolateral abdominal wall. The morphological measurements for splenic length, width, and thickness were 26.6 ± 7.67, 4.17 ± 1.65, and 1.70 ± 0.01 mm, respectively. The histological observations showed that the splenic capsule was composed of two layers (serosal and subserosal). The inner layer sends trabeculae dividing the splenic parenchyma irregularly, and the splenic parenchyma comprises the white and red pulp. The white pulp follicles included the mantle, marginal zones, and the PALS (periarterial lymphatic sheath), while the red pulp constituted splenic cords and sinuses. The histomorphological findings showed that white pulp follicles and the central artery mean diameter were 252.62 ± 8.07 µm and 54.45 ± 0.36 µm respectively, the proportion of white to a red pulp was 0.49 ± 0.01, the splenic capsule, trabecula and the wall of splenic arteries showed an intense positive activity to PAS stain and negative or weak in other splenic structures. Conclusion: The similarities and differences in the spleen between the laboratory animals and hamsters were apparent in this article, so understanding the morphological and histological structure of the spleen presents significant assistance with species identification to select the appropriate experimental animal model in future medical research.

Preliminary experience with a new robotic technique to facilitate distal pancreatectomy with spleen preservation: left lateral approach in right lateral decubitus position.

Spleen-preserving distal pancreatectomy (SP-DP), for patients with benign or small low-grade malignant tumors of the body or tail of the pancreas, is the ideal procedure although it is technically demanding. The robotic da Vinci system has been introduced to overcome these technical challenges and reduce operative risks. We report our experience of a new variation in surgical technique: the left lateral approach robotic spleen-preserving distal pancreatectomy (RSP-DP) in right lateral decubitus position. We performed this new variant of SP-DP, in five patients, using the da Vinci Xi system. Technical and clinical feasibility are described. The mean age and body mass index were 53.4 years and 31.4 kg/m2, respectively. The mean total operative time was 323 min. The estimated mean blood loss was 240 ml. In all patients, the spleen could be preserved. In four patients, the splenic vessels were also preserved. One patient required a Warshaw technique due to significant fibrosis attached to the splenic vein. The postoperative period of all patients was uneventful except the presence of biochemical leak (BL) in two patients that only required maintenance of the drainage at home. The mean length of hospital stay was 6 days after surgery. The left lateral approach robotic SP-DP in right lateral decubitus position is a feasible and safe procedure for distal benign or small low-grade malignant tumors of the left pancreas. The right lateral decubitus position associated to robotic surgery can facilitate this complex procedure, especially when splenic vessels preservation is indicated, with a lower risk of conversion and shortening of the learning curve.

Long-Term Effects of Proximal Splenic Artery Embolization on Splenic Volume and Platelet Count.

BACKGROUND: The spleen is the most commonly injured visceral organ in blunt abdominal trauma. Post-splenectomy infection risk has led to the shift toward spleen preserving procedures and splenic artery embolization (SAE) is now the treatment of choice for hemodynamically stable patients with splenic injury. This study aims to assess the long-term effect of SAE on splenic volume and platelet count. MATERIALS AND METHODS: Using CPT codes, 66 patients who underwent SAE were identified, and 14 of those who had the necessary imaging and laboratory follow-up were included in the study. Indications for SAE were portal hypertension in 8 patients, bleeding in 4 patients, and thrombocytopenia in 1, and one patient had a separate indication. Splenic volume was calculated by automated volumetric software (Aquarius, TeraRecon, Inc.). Paired t-tests were performed to compare splenic volume and platelets before and after SAE. RESULTS: Fourteen patients (7 males, 7 females) with a mean age of 51 ± 11.95 years underwent SAE and were followed by a repeat computed tomography scan at an average of 733.57 days. Nine SAEs were performed using vascular plugs, 3 using micro coils, and 2 out of that were with Gelfoam slurry, and 2 using coils only. All embolizations were technically successful with complete cessation of flow. Mean splenic volumes pre- and post-SAE were 903.5 ± 523.73 cm3 and 746.5 ± 511.95 cm3, respectively, representing a mean decrease of 8.31% compared to baseline [P = 0.346]. Minimum platelet counts (x103) pre-SAE (within 3 months) and post-SAE (2 weeks to 3 months after the procedure) were 55.79 ± 57.11 and 116 ± 145.40, respectively. The minimum platelet count showed a statistically significant mean increase of 134.92% (P = 0.033). CONCLUSIONS: The splenic volume is not altered significantly by SAE in the long term. Similarly, the platelet count is also not significantly altered at 3 months follow-up. This study, although small, suggests that SAE is a safe intervention that can preserve splenic volume and function in the long term.

Comparing the Warshaw technique with vessel-preservation in laparoscopic spleen preserving distal pancreatectomy: is there a better approach?

BACKGROUND: Laparoscopic spleen-preserving distal pancreatectomy (LSPDP) can be accomplished with either resection of the splenic vessels via the Warshaw Technique (WT) or via preservation of the splenic vessels (SVP). Our study aims to compare outcomes for the two methods of LSPDP. METHODS: We performed a retrospective chart review with intent-to-treat analysis of adults undergoing LSPDP at a single institution from 2009 to 2021. We compared demographic characteristics, operative parameters, oncologic pathology review, and postoperative outcomes. RESULTS: There were 102 consecutive cases of LSPDP (59 WT, 43 SVP) over 12 years. The rate of successful spleen preservation was not significantly different between the two groups (76.3%WT, 65.1%VSP,p = 0.27). Rates of conversion to laparotomy, postoperative complications including pancreatic fistulas and splenic infarcts and amount of intraoperative blood loss were similar between the groups. Median operative time was significantly shorter with the WT (141 vs. 177 min, p < 0.05). The median length of stay in hospital was not significantly different among the groups. CONCLUSION: Both techniques are safe and effective in preserving the spleen in laparoscopic distal pancreatectomy. Our experience suggests that the Warshaw Technique may be more efficient with respect to the use of limited operative resources.

A retrospective multi-centre study of splenic volumes measured by CT following splenic artery angioembolisation for high-grade blunt splenic injuries in adults.

INTRODUCTION: Splenic artery embolisation is a recognised modality in the management of high grade blunt splenic injury. The impact of embolisation on the spleen in terms of volume and function remains unclear. This results in a lack of clarity regarding post embolisation vaccination policy. METHODS: This was a two-centre, retrospective observational study over a 24-month period involving all patients who underwent splenic artery embolisation for high grade blunt splenic trauma (AAST grades III-V). Splenic volumes were calculated from an initial CT and a repeat CT at 6 months post embolisation. Subgroup analysis was performed analysing the location of embolisation, AAST grading, and evidence of splenic dysfunction as defined by the presence of altered red cell morphology. RESULTS: Thirty patients achieved successful splenic salvage with angioembolisation. Mean volume loss was 44.14 cm3 (P = 0.038), with decreased volumes for distal embolisation and increased volumes for proximal embolisation. Three patients had altered red cell morphology; two demonstrated recovery at 6 months, with the third lost to follow up. There were significant associations between, initial splenic volume, AAST grade of injury, and altered red cell morphology. There was no significant association between location of embolisation, initial splenic volumes, or percentage volume change. CONCLUSION: This study demonstrated a statistically significant change in splenic volume post angioembolisation in trauma, which was associated with AAST grading but not location of embolisation. The low rate of altered red cell morphology appears transient.

Anatomo-topographic and histo-cytological study of dromedary's spleen in Algeria.

BACKGROUND: Twenty-five spleens of adult, healthy dromedary of the local breed from the region of El Oued, Algeria, were collected at the slaughterhouse in order to carry out research to determine the macroscopic and microscopic structure of spleen in this species, macroscopic study revealed that the spleen has a rectangular shape with a triangular section, rounded edges, a little bit striated, its surface is smooth in which the aspect of the capsule and the parietal surface is shiny and smooth, the morphometric study was carried out after classifying the sampled spleen in five groups according to the animal's body weight which increases with age. MATERIALS AND METHODS: Our study revealed that the groups show a different value of mass which declines towards a drop of the index, also the indexes of length and width are following a decreasing order. RESULTS: The histological study revealed that the zone occupied by stroma did not exceed 26.81% of the total components of the capsule which is composed essentially of connective tissue and an inner layer of smooth muscle cells. Vascular and avascular trabeculae extend from the capsule. The immunohistochemistry study made it possible to visualise T lymphocytes of the splenic parenchyma using monoclonal antibodies where a statistical study was carried out to determine the composition of the various compartments of this organ. The localisation of immunocompetent cells in the splenic parenchyma has been elucidated with antibodies specific for T lymphocytes. CONCLUSIONS: The red pulp occupied a maximum area of the spleen with an average of 68.1% composed of sinusoids venous, the cords extend between the sinuses and the interlobular zone contain many cells: macrophages, plasma cells, red blood cells, white blood cells and platelets.

The human splenic microcirculation is entirely open as shown by 3D models in virtual reality.

The human spleen is equipped with an organ-specific microcirculation. The initial part of the venous circulation is formed by spleen-specific large microvessels, the sinuses. Sinuses eventually fuse to form venules and veins. For more than 170 years there have been debates, whether splenic red pulp capillaries join sinuses, i.e., whether the microcirculation is closed or open-or even simultaneously closed and open. We have now solved this question by three-dimensional reconstruction of a limited number of immunostained serial sections of red and white pulp areas, which were visualized in virtual reality. Splenic capillaries have special end structures exhibiting multiple small diverging endothelial cell processes, which always keep a certain distance to the walls of sinuses. Only very few capillary ends were difficult to diagnose. Positive identification of these end structures permits to conclude that the human splenic microcirculation is entirely open. This is also true for the perifollicular capillary network and for capillaries close to red pulp venules. Follicles are supplied by a relatively dense open perifollicular capillary net, which is primarily, but not exclusively, fed by sheathed and few non-sheathed capillaries from the surrounding red pulp network.

Measurement of normal spleen volume and dimensions in all child age groups by abdominal computed tomography.

OBJECTIVE: This study aimed to calculate the spleen size and volume, portal vein diameter, splenic vein diameter, and accessory spleen presence in children aged 0-18 years in the Turkish population by computed tomography, according to age and gender. MATERIALS AND METHODS: Abdominal computed tomography images of 406 children without systemic or organospecific disease were retrospectively analyzed in the study. Maximum interpolar length in axial and coronal sections in addition to maximum width at hilus level in axial sections of the spleen were measured in abdominal computed tomography. Luminal diameter measurements were obtained from axial sections at the level of the liver hilum of the portal vein and the hilus of the spleen of the splenic vein. RESULTS: As age increases, the axial longest dimension (ALD), axial longest thickness (ALT) and coronal longest dimension (CLD) dimensions also increase, and this increase is statistically significant (p<0.001). The lowest splenic volume was measured in the 0-2 age group as 25.3 cm3, and the highest splenic volume was 506.2 cm3 in the 17-18 age group. Splenic vein diameter is between 1.9 mm and 11.0 mm, and the mean splenic vein diameter increases with increasing age. Portal vein diameter is between 4.1 mm and 14.9 mm, and the average portal vein diameter increases with age. The accessory spleen was seen in 22 (5.4%) children. Accessory spleen size ranged from 5 mm to 17 mm. There was a strong positive correlation between spleen volume and splenic vein diameter (r=0.696 p<0.001). Similarly, there was a strong positive correlation between spleen volume and portal vein diameter (r=0.704 p<0.001). CONCLUSIONS: It may be helpful to know the normal spleen volume in healthy children according to age groups in making the correct diagnosis of splenomegaly. We assume that it will play an important role in the accurate diagnosis of portal hypertension to know the upper and lower limits of the portal vein and splenic vein diameters.

Spleen-preserving total pancreatectomy and islet autotransplantation with complete preservation of the splenic arterial and venous supply does not impact islet yield and function.

BACKGROUND: Standard total pancreatectomy and islet autotransplantation (TPIAT) for chronic pancreatitis includes splenectomy, but TPIAT can be performed without splenectomy by full preservation of the blood supply to the spleen. METHODS: We compared the metabolic and clinical outcomes of patients who underwent TPIAT at our center between 2015 and 2021 with or without splenectomy. A total of 89 patients were included in the study, and 17 of them underwent spleen-preserving total pancreatectomy (SPTP). RESULTS: The two study groups had similar demographic and metabolic parameters. Short-term morbidity and long-term outcomes were similar. The operative time was significantly shorter with splenectomy: a median of 9.91 h (interquartile range [IQR] 8.89-10.83) compared to 10.78 h (IQR 10.2-11.6) for SPTP (P = 0.021). There was no difference between the groups in postoperative morbidity. Metabolic outcomes at 1 year were better in the SPTP group compared to the splenectomy group, with a median daily insulin requirement of 7 units (IQR 4-12) vs 15 units (IQR 7-26; P = 0.049) and a median C-peptide at 1 year of 0.65 (IQR 0.40-1.26) vs 1.00 (IQR 0.80-1.90; P = 0.63). The reduction in morphine milligram equivalents per day over time was significantly better in the SPTP group (P < 0.001), as was the decrease in pain score (P < 0.001). CONCLUSION: TPIAT with full arterial and venous preservation of the spleen had no adverse impact on islet yield or function. TPIAT can be safely and effectively performed with preservation of the spleen and the entire splenic artery and vein. The spleen should be preserved when feasible in every TPIAT surgery.

Progression of Portal Hypertension in Acute Cellular Rejection After Liver Transplantation.

OBJECTIVES: This study was designed to investigate the frequency of computed tomography features indicating progression of portal hypertension and their clinical relevance in patients who experienced acute cellular rejection after liver transplantation. MATERIALS AND METHODS: This retrospective study included 141 patients with pathologically diagnosed acute cellular rejection following liver transplant. Patients were divided into early and late rejection groups according to the time of diagnosis. Two radiologists analyzed the interval changes in spleen size and variceal engorgement on computed tomography images obtained at the times of surgery and biopsy. Aggravation of splenomegaly and variceal engorgement were considered computed tomography features associated with the progression of portal hypertension. Clinical outcomes, including responses to treatment and graft survival, were compared between patients with and without these features. RESULTS: The frequency of progression of portal hypertension was 31.9% and did not differ significantly in patients who experienced early (30.8% [28/91]) and late (34.0% [17/50]) rejection (P = .694). In the late rejection group, computed tomography features indicating progression of portal hypertension were significantly associated with poor response to treatment (P = .033). Graft survival in both the early and late rejection groups did not differ significantly in patients with and without progression of portal hypertension. CONCLUSIONS: Computed tomography features suggesting the progression of portal hypertension were encountered in about one-third of patients who experienced acute cellular rejection after liver transplant. Progression of portal hypertension was significantly related to poor response to treatment in the late rejection group.

Immune Function After Splenic Artery Embolization for Blunt Trauma: Long-Term Assessment of CD27+ IgM B-Cell Levels.

Splenic artery embolization (SAE) plays a critical role in the treatment of high-grade splenic injury not requiring emergent laparotomy. SAE preserves splenic tissue, and growing evidence demonstrates preserved short-term splenic immune function after SAE. However, long-term function is less studied. Patients who underwent SAE for blunt abdominal trauma over a 10-year period were contacted for long-term follow-up. Sixteen participants (sex: women, 10, and men, 6; age: median, 34 years, and range, 18-67 years) were followed up at a median of 7.7 years (range, 4.7-12.8 years) after embolization. Splenic lacerations were of American Association for the Surgery of Trauma grades III to V, and 14 procedures involved proximal embolization. All individuals had measurable levels of IgM memory B cells (median, 14.30 as %B cells), splenic tissue present on ultrasound (median, 122 mL), and no history of severe infection since SAE. In conclusion, this study quantitatively demonstrated that long-term immune function remains after SAE for blunt abdominal trauma based on the IgM memory B cell levels.

CD97 promotes spleen dendritic cell homeostasis through the mechanosensing of red blood cells.

Dendritic cells (DCs) are crucial for initiating adaptive immune responses. However, the factors that control DC positioning and homeostasis are incompletely understood. We found that type-2 conventional DCs (cDC2s) in the spleen depend on Gα13 and adhesion G protein-coupled receptor family member-E5 (Adgre5, or CD97) for positioning in blood-exposed locations. CD97 function required its autoproteolytic cleavage. CD55 is a CD97 ligand, and cDC2 interaction with CD55-expressing red blood cells (RBCs) under shear stress conditions caused extraction of the regulatory CD97 N-terminal fragment. Deficiency in CD55-CD97 signaling led to loss of splenic cDC2s into the circulation and defective lymphocyte responses to blood-borne antigens. Thus, CD97 mechanosensing of RBCs establishes a migration and gene expression program that optimizes the antigen capture and presentation functions of splenic cDC2s.