The surgical anatomy of the spleen

Distribution of Splenic Arterial Flow and Segmental Spleen Volume for Partial Splenic Arterial Embolization

INTRODUCTION

The spleen is a lymphatic organ that manages immune surveillance of the blood, produces blood cells, and helps filter the blood, remove old blood cells, and fight infection. The normal splenic weight is approximately 65-265 g. This study evaluated spleen volume and segmental volume.

METHODS

121 patients who underwent enhanced CT at our center were analyzed. The spleen was divided into upper, middle, and lower segments according to arterial flow area, and the volume of each segment was measured. Patients were classified into two groups as those with and without liver cirrhosis, and differences in the distribution of the segments in these groups was evaluated.

RESULTS

The mean upper, middle, and lower spleen segmental volume ratios were 35.4%, 37.0%, and 27.6%, respectively. In the liver cirrhosis group, the segmental splenic volume ratios for the upper, middle, and lower segments were 34.5%, 38.5%, and 28.0%, respectively, indicating that these ratios remain similar regardless of liver cirrhosis status.

CONCLUSION

The present findings on segmental spleen volume are useful for estimating infarction volume in cases of partial splenic arterial embolization.

Focal splenic lesions: Imaging spectrum of diseases on CT, MRI and PET/CT

The spleen can be affected by a variety of diseases. Some of them are readily identified as variations of normal or benign diseases on imaging. However, for a substantial number of focal splenic abnormalities, the diagnosis can be difficult so that histopathologic analysis may be required for a definite diagnosis. In this review, the typical splenic abnormalities that can be diagnosed with imaging with a high degree of confidence are illustrated. The complementary role of computed tomography (CT), magnetic resonance imaging and positron emission tomography/CT that helps make a diagnostic approach is discussed. Finally, current applications and future trends of radiomics and artificial intelligence for the diagnosis of splenic diseases are addressed.

Chronic splenic artery occlusion with gastric wall arterial ectasia, an unusual cause of massive upper gastrointestinal hemorrhage

Life-threatening upper gastrointestinal (GI) hemorrhage can occur as a result of bleeding from a variety of arterial and venous sources. We present an unusual cause of life-threatening upper GI hemorrhage arising from ectatic gastric wall arterial branches in a 49-year-old male with previously unrecognized chronic splenic artery thrombosis. The patient developed a recurrence of bleeding despite coil embolization of an accessory left gastric artery branch supplying the gastric fundus suspected to be the site of active bleeding. The patient subsequently underwent splenectomy and surgical ligation of a bleeding gastric artery branch. This case emphasizes the importance of recognizing this unusual cause of upper GI hemorrhage for proper management and prevention of recurrence. Informed consent was obtained from the patient for publication of the case report including accompanying images.

Development and Implementation of a Novel Computer-Based Training Module for the Standardization of Splenic Flexure Mobilization

BACKGROUND

Computer-based training modules use various multimedia components such as text, graphics, animation, and videos that can theoretically facilitate the learning process. Splenic flexure mobilization (SFM) is a crucial step for tension-free colorectal/anal anastomosis that can be a technically demanding step. This study is designed to demonstrate our novel training module for SFM with high-vessel ligation during surgery and present the anatomical landmarks and embryological plans for SFM.

MATERIALS AND METHODS

A step-by-step educational video was prepared to standardize and teach the technical steps of the SFM. 3D animation was prepared and cadaveric dissection was performed in a step-by-step manner similar to minimally invasive surgery. This is followed by the laparoscopic technique. Since we have started this modular training program in our department, a consecutive of 100 patients underwent laparoscopic low anterior resection and coloanal anastomosis with covering stoma. Demographics, characteristics, and postoperative outcomes were evaluated.

RESULTS

Surgical anatomical planes and important vascular structures/variations are both shown by 3D animation, cadaveric dissection, and laparoscopic surgery. Out of 100 consecutive cases, there were no mortality, 5 anastomotic leakages 1 of which necessitates reoperation, and 2 splenic injuries which were managed conservatively.

CONCLUSION

This unique educational video module for SFM demonstrates surgical anatomical planes and important vascular structures/variations. The employment and implementation of time-independent multimedia components lead to effective training and can theoretically facilitate the learning process.

A review of anatomy, pathology, and disease spread in the perisplenic region

The perisplenic region is a complex anatomical area involving multiple peritoneal and subperitoneal structures, which influence the presentation and behavior of various pathologic processes. This review is a comprehensive resource for perisplenic anatomy and pathology with associated clinical presentations and imaging findings. Understanding the pathophysiologic intricacies of the perisplenic region assists the radiologist in building a helpful differential diagnosis and recognizing predictable disease patterns.

A systematic review of splenic artery variants based on cadaveric studies

PURPOSE

The splenic artery (SA) is the largest and most tortuous branch of the celiac trunk with a wide spectrum of variants, particularly in its terminal branches.

METHODS

The current study presents a systematic review of the English literature on the SA variations, with emphasis on its terminal branching patterns.

RESULTS

Thirty cadaveric studies (3132 specimens) were included in the analysis. The SA originated from the celiac trunk in 97.2%, from the abdominal aorta in 2.1% and from the superior mesenteric or the common hepatic artery in 0.7% of cases. A suprapancreatic course was observed in 77.4%, retropancreatic course in 17.8%, anteropancreatic course in 3.4% and intrapancreatic course in 1.3%. In the majority of cases, the SA bifurcated into superior and inferior lobar arteries (83.4%), with trifurcation and quadrifurcation in 11.3% and 2.7%, respectively. Five or more lobar branches (1.4%) and a single lobar artery (1.2%) were rarely identified. The distributed branching pattern was found in 72.7%, whereas the magistral pattern in 26.9%. The inferior and superior polar arteries (IPA and SPA) were found in 47.7% and 41.7% of cases, respectively, while polar artery agenesis was recorded in 28.2%. The SPA usually originated from the SA main trunk (53.6%) or from the superior lobar artery (33.1%). The IPA emanated mainly from the left gastroepiploic artery (53%), from the SA (23.5%) or the inferior lobar artery (21.9%). Intersegmental anastomoses between adjacent arterial segments were identified in 14.2%.

CONCLUSION

Knowledge of the SA aberrations is important for surgeons and radiologists involved in angiographic interventions.

A report of a case: unusual portosystemic shunt in a hernia sac who has portal hypertension due to cirrhosis

BACKGROUND

Variations in the origin and branching pattern of splenic vein (SV) are relatively rare and asymptomatic. We describe here only the first case in the literature of accessory SV in hernia sac due to previous operation and increased portal pressure because of cirrhosis.

CASE PRESENTATION

This report describes a 66-year-old female, with a history of total abdominal hysterectomy (TAH) due to uterine myomatosis, signs of cirrhosis onset due to hepatitis B, who had been presented with recurrent abdominal pain attacks. Ultrasonography (USG) findings were nothing pathologic except a gallstone in the gallbladder without cholecystitis signs. Incisional hernia was found to contain an accessory SV in the hernia sac arising from a branch of main SV in the hilum, ongoing to the subcutaneous fat tissue and draining to the superficial femoral vein on computed tomography (CT). Videoendoscopy showed wide gastritis and multiple ulcers. The patient's symptoms diminished with proton pump inhibitor (PPI) treatment and they then underwent a hernia repair surgery with Prolene mesh patch as elective surgery.

CONCLUSIONS

A thorough knowledge of the normal anatomy, most frequent variations and congenital or acquired anomalies of the spleno-portal axis has great importance for hepatopancreaticobiliary and emergency surgical procedures. It is, therefore, essential for preoperative evaluation of the anatomical details of the spleno-portal venous axis and should be evaluated with imaging methods in detail.

Clinical Significance of Splenic Vessels and Anatomical Features in Laparoscopic Splenectomy

Introduction: Laparoscopic splenectomy (LS) has become the standard treatment for benign hematological disorders and hypersplenism. However, serious complications such as pancreatic fistula and portal venous thrombosis (PVT) sometimes occur. We investigated the clinical significance of splenic vessels and anatomical features in LS. Methods: Patient data were collected from 32 patients who underwent LS. The indications for LS were hypersplenism due to liver cirrhosis, idiopathic thrombocytopenic purpura, hereditary spherocytosis, and others. Close contact of pancreatic tail with splenic hilum, spleen volume, and diameters of splenic vessels were evaluated on computed tomography images. Results: Close contact of pancreatic tail with splenic hilum was recognized in 15 of the patients. The close contact was significantly associated with operation time (P = .038), spleen volume (P = .021), and spleen volume/body surface area (BSA) ratio (P = .001). In multivariate analysis, spleen volume/BSA ratio was an independent factor for close contact (P = .022). PVT occurred in 3 cirrhosis patients, and the diameter of the splenic vein (SV) was significantly associated with PVT as a result of multivariate analysis (P = .027). Conclusion: Close contact of the pancreatic tail with the splenic hilum may cause a longer operation time at LS and be associated with spleen volume/BSA ratio. A larger SV diameter in cirrhosis patients may be related to PVT after LS.

Innervation of the human spleen: A complete hilum-embedding approach

INTRODUCTION

The spleen is hypothesized to play a role in the autonomic nervous system (ANS)-mediated control of host defence, but the neuroanatomical evidence for this assumption rests on a sparse number of studies, which mutually disagree with respect to the existence of cholinergic or vagal innervation.

METHODS

We conducted an immuno- and enzyme-histochemical study of the innervation of the human spleen using a complete hilum-embedding approach to ensure that only nerves that entered or left the spleen were studied, and that all splenic nerves were included in the sampled area. Furthermore, a complete embedded spleen was serially sectioned to prepare a 3D reconstruction of the hilar nerve plexus.

RESULTS

All detected nerves entering the spleen arise from the nerve plexus that surrounds branches of the splenic artery and are catecholaminergic. Inside the spleen these nerves continue within the adventitia of the white pulpal central arteries and red pulpal arterioles. Staining for either choline acetyltransferase or acetylcholinesterase did not reveal any evidence for cholinergic innervation of the human spleen, irrespective of the type of fixation (regularly fixed, fresh-frozen post-fixed or fresh-frozen cryoslides). Furthermore, no positive VIP staining was observed (VIP is often co-expressed in postganglionic parasympathetic nerves).

CONCLUSION

Our comprehensive approach did not produce any evidence for a direct cholinergic (or VIP-ergic) innervation of the spleen. This finding does not rule out (indirect) vagal innervation via postganglionic non-cholinergic periarterial fibres.

A novel approach for robotic mobilization of the splenic flexure

BACKGROUND

The techniques of robotic splenic flexure mobilization in the colorectal surgery setting are not well defined and have been challenging due to limited range of motion of the second-generation robotic platform in multiple quadrants.

METHODS

This report describes a novel technique for robotic splenic flexure mobilization with medial-to-lateral approach without a need for robotic cart repositioning during left-sided colon and rectal surgery. The dissection is started with ligation of the inferior mesenteric artery and vein. Unique in this approach, entering the lesser sac is accomplished by extension of the dissection cranially by lifting up the mesocolon from the anterior surface of the pancreatic body toward the stomach.

RESULTS

This technique presented in the video allows the mobilization of the splenic flexure without excessive tractions and avoidance of potential splenic injuries.

CONCLUSIONS

The described novel approach demonstrates total robotic splenic flexure takedown without excessive traction, with improved visualization, and reduction of potential risk of splenic injury. This approach provides totally robotic mobilization of the splenic flexure at single docking without changing the patient's position.

Anteriorly placed splenic vein: a case report

Splenic vein located anterior to pancreas is a rare congenital anomaly. To date, only one case has been reported in literature. A thorough knowledge of the normal anatomy, most frequent variations, and congenital and acquired anomalies of the spleno-portal axis is of great importance for hepatobiliary and pancreatic surgeons. It is therefore essential for preoperative evaluation of the anatomical details of the spleno-portal venous axis to be made by imaging. We report such a case of anteriorly placed splenic vein in a 40-year-old female prospective renal donor. To the best of our knowledge, this represents the second reported case of an anteriorly placed splenic vein.

Scintigraphic study of the splenic circulation in rats

OBJECTIVE

To evaluate the splenic parenchymal blood distribution through scintigraphic study.

METHODS

Thirty Wistar rats were randomly divided into six groups (n = 5). Group 1 (spleen - 30 minutes) and Group 2 (spleen - 90 minutes) underwent laparotomy with direction of blood flow to the spleen by ligature of the aorta near the iliac bifurcation and splanchnic vessels, keeping blood flow only in the splenic artery; Group 3 (spleen and stomach - 30 minutes) and Group 4 (spleen and stomach - 90 minutes) underwent laparotomy with direction of blood flow to the spleen and stomach by ligature of the aorta near the iliac bifurcation and splanchnic vessels, maintaining the flow through the splenic, gastric and splenogastric vessels; Group 5 (control - 30 minutes) and Group 6 (control - 90 minutes) underwent laparotomy and ligation of the aorta near the iliac bifurcation, keeping the flow to the abdominal organs. After arterial ligation, the animals received an injection of 0.2 ml of sodium pertechnetate in the aorta. Scintigraphic images were taken and the animals had their spleens removed for radioactivity counting with an automatic counter device.

RESULTS

There was no difference in the amounts of radiation from the spleen between groups, indicating retention of the radioisotope by the spleen, even after the period of 90 minutes.

CONCLUSION

The blood flow through the spleen is not continuous. The blood diffuses through the splenic parenchyma and its venous drainage is slow, not following a predictable sequence.

Does laparoscopy reduce splenic injuries during colorectal resections? An assessment from the ACS-NSQIP database

BACKGROUND

Nearly half of all incidental splenectomies caused by iatrogenic splenic injury occur during colorectal surgery. This study evaluates factors associated with incidental splenic procedures during colorectal surgery and their impact on short-term outcomes using a nationwide database.

METHODS

Patients who underwent colorectal resections between 2005 and 2012 were identified from the American College of Surgeons National Surgical Quality Improvement Program database according to Current Procedural Terminology codes. Patients were classified into two groups based on whether they underwent a concurrent incidental splenic procedure at the time of the colorectal procedure. All splenic procedures except a preoperatively intended splenectomy performed in conjunction with colon or rectal resections were considered as incidental. Perioperative and short-term (30 day) outcomes were compared between the groups.

RESULTS

In total, 93633 patients who underwent colon and/or rectal resection were identified. Among these, 215 patients had incidental splenic procedures (153 open splenectomy, 17 laparoscopic splenectomy, 36 splenorraphy, and 9 partial splenectomy). Open colorectal resections were associated with a significantly increased likelihood of incidental splenic procedures (OR 6.58, p < 0.001) compared to laparoscopic surgery. Incidental splenic procedures were associated with increased length of total hospital stay (OR 1.25, p < 0.001), mechanical ventilation dependency (OR 1.62, p = 0.02), transfusion requirement (OR: 3.84, p < 0.001), re-operation requirement (OR 1.7, p = 0.005), and sepsis (OR: 2.03, p = 0.001). Short-term advantages of splenic salvage (splenorraphy or partial splenectomy) included shorter length of total hospital stay (p = 0.001) and decreased need for re-operation (p < 0.001).

CONCLUSIONS

Incidental splenic procedures during colorectal resections are associated with worse short-term outcomes. Use of the laparoscopic technique decreases the need for incidental splenic procedures.

Laparoscopic splenectomy: standardized approach

Laparoscopic splenectomy was first reported in 1991-1992 by several groups. The impact and role of laparoscopy for splenectomy can be considered as significant as that for gallbladder disease, achalasia, esophageal reflux, and adrenal disease. In many centers, the laparoscopic approach is now routine for most cases of elective splenectomy. The laparoscopic approach is associated with reduced morbidity, especially pulmonary, wound, and infectious complications. This article reviews a standardized approach to laparoscopic and hand-assisted splenectomy and covers indications, operative strategy, and complications. Several special considerations, including massive splenomegaly, postsplenectomy thrombosis of the portosplenic venous system, and accessory spleens are also discussed.

Anatomic mechanisms for splenic injury during colorectal surgery

Intraoperative iatrogenic splenic injury during colorectal surgery is rare but may cause significant morbidity. We aimed to describe the anatomic mechanisms of iatrogenic injury to the spleen during colonic surgery. All adult surgical patients who sustained a splenic injury during colectomy at our institution from 1992 to 2007 were retrospectively identified. The operative and pathologic reports were reviewed, and anatomic details of the injuries were collected. Results are reported as a proportion or median, with range reported in brackets. Of 13,897 colectomies, 71 splenic injuries among 58 patients were identified. Splenic flexure colonic mobilization occurred in 53 (91%) of these patients. The median number of tears was 1 (1-3). The average length of tear was 4.59 cm. The distribution of injury location on the spleen was 24 (34%) inferior, 14 (20%) hilar, 3 (4%) posterior, 2 (3%) lateral, and 1 (1%) superior. Three (4%) patients suffered from splenic rupture. The location of 24 (34%) injuries was not described. Capsular tears were the cause of splenic injury in 55 (95%) patients. Intraoperative splenic injury ultimately resulted in splenectomy in 44 (76%) patients. Splenic injury was a delayed finding requiring reoperation in 4 (7%) patients. The primary mechanism of intraoperative splenic injury during colectomy is capsular tears and lacerations secondary to misplaced traction and tension on the spleen during colonic mobilization. Techniques to lessen these forces may decrease the number of injuries and subsequent splenectomy.

Development of spleen during the fetal period

OBJECTIVE

This study was aimed to determine the location and development of the spleen in the human fetuses.

MATERIALS AND METHODS

The study was carried on 141 dead human fetuses aged between 9 and 40 weeks with no marked pathology and anomaly in the years 2002-2003. The location of spleen with the neighboring structures, the existence of accessory spleens, notches on the borders, fissures on the surfaces, major ligaments and the shape of spleen and its hilum were established. The spleen was completely observed intraperitoneally (except at the hilum), in the left hypochondrium throughout the fetal period. The length, width, thickness, weight, volume, and the hilum dimensions of spleen were measured.

RESULTS

The dimensions, weight, and volume of the spleen were increased with the gestational age, and positive significant correlations were determined (P < 0.001). There was no difference between sexes in all parameters (P > 0.05). The length of the spleen has ranged between 3.1 and 35.6 mm, between 9 weeks old and 40-week-old fetuses, respectively. One or more accessory spleens have been found in 14% of cases.

CONCLUSION

The measurements and location of the spleen according to the gestational age were determined by the present study. The expression of morphometric parameters of the spleen at different gestational ages can be used in determination of pathologies of the spleen and may also contribute to future studies on this issue.

Central pancreatectomy for benign pancreatic pathology/trauma: is it a reasonable pancreas-preserving conservative surgical strategy alternative to standard major pancreatic resection?

BACKGROUND

The aim of this study was to assess the technical feasibility, safety and outcome of central pancreatectomy (CP) with pancreaticogastrostomy or pancreaticojejunostomy in appropriately selected patients with benign central pancreatic pathology/trauma. Benign lesions/trauma of the pancreatic neck and proximal body pose an interesting surgical challenge. CP is an operation that allows resection of benign tumours located in the pancreatic isthmus that are not suitable for enucleation.

METHODS

Between January 2000 and December 2005, eight central pancreatectomies were carried out. There were six women and two men with a mean age of 35.7 years. The cephalic pancreatic stump is oversewn and the distal stump is anastomosed end-to-end with a Roux-en-Y jejunal loop in two and with the stomach in six patients. The indications for CP were: non-functional islet cell tumours in two patients, traumatic pancreatic neck transection in two and one each for insulinoma, solid pseudopapillary tumour, splenic artery pseudoaneurysm and pseudocyst. Pancreatic exocrine function was evaluated by a questionnaire method. Endocrine function was evaluated by blood glucose level.

RESULTS

Morbidity rate was 37.5% with no operative mortality. Mean postoperative hospital stay was 10.5 days. Neither of the patients developed pancreatic fistula nor required reoperations or interventional radiological procedures. At a mean follow up of 26.4 months, no patient had evidence of endocrine or exocrine pancreatic insufficiency, all the patients were alive and well without clinical and imaging evidence of disease recurrence.

CONCLUSION

When technically feasible, CP is a safe, pancreas-preserving pancreatectomy for non-enucleable benign pancreatic pathology/trauma confined to pancreatic isthmus that allows for cure of the disease without loss of substantial amount of normal pancreatic parenchyma with preservation of exocrine/endocrine function and without interruption of enteric continuity.

Oxidant stress and haemolysis of the human erythrocyte

The erythrocyte is a highly specialised cell with a limited metabolic repertoire. As an oxygen shuttle, it must continue to perform this essential task while exposed to a wide range of environments on each vascular circuit, and to a variety of xenobiotics across its lifetime. During this time, it must continuously ward off oxidant stress on the haeme iron, the globin chain and on other essential cellular molecules. Haemolysis, the acceleration of the normal turnover of senescent erythrocytes, follows severe and irreversible oxidant injury. A detailed understanding of the molecular mechanisms underlying oxidant injury and its reversal, and of the clinical and laboratory features of haemolysis is important to the medical toxicologist. This review will also briefly review glucose-6-phosphate deficiency, a common but heterogeneous range of enzyme-deficient states, which impairs the ability of the erythrocyte to respond to oxidant injury.

Anteriorly Placed Splenic Vein: The First Reported Case

Surgical treatment of portal hypertension is undertaken to reduce the portal pressure to a level that allows recession of the collateral circulation. For this purpose, surgeons usually carry out anastomosis of the splenic vein with the left renal vein. The splenic vein is a large, nontortuous vessel that runs along the posterior surface of the pancreas but very rarely crosses in front of the gland. It is therefore important that a thorough preoperative study of the anatomical details of the spleno-portal venous axis be made by imaging before attempting surgery. We are presenting herewith the surgical management of a unique case of anteriorly placed splenic vein, which has not yet been described. The embryological basis of such an anomaly is discussed in this article.

Partial dearterialization of the spleen in thalassemia major

METHODS

Nine patients with thalassemia major (8 boys, 1 girl; age 3 to 8 years) who had signs of hypersplenism and required more than one blood transfusion per month (1 to 2 weeks) underwent partial dearterialization of the spleen (PDAS) from April through December 1992. All were on a low transfusion regimen (Hb < 10 g%). Hematologic profile, IgM and splenic dimensions (SD) by sonography were determined preoperatively and postoperatively during follow-up periods. Isotopic scan was also performed a few months and 2 to 4 years after operation. The patients did not receive pneumovax or long-term prophylactic antibiotics. The procedure consists of division of the splenic arterial branches, except the one that supplies the superior pole, along with preservation of all the veins.

RESULTS

Seven patients with SD less than 11 cm (6.9 to 10.8 cm; four with less than 9.5 cm) had uneventful recovery. Two others with SD greater than 13 cm (13.2 to 13.5 cm) required total splenectomy a few days after PDAS because of splenic enlargement associated with high fever. One patient was lost to follow-up after 18 months. The remaining six patients underwent follow-up for 4 to 4.5 years. The hematologic profile (Hb, RBC, platelet counts) showed significant improvement during follow-up period. The blood transfusion requirement in all patients was once every 25 to 32 days except one in which transfusion was increased to every 2 to 3 weeks during the fourth postoperative year. The ultimate magnitude of the hematologic response compared with 15 matched splenectomized patients studied retrospectively in a 4-year period was almost the same in the majority after the first postsplenectomy year. There was no significant change in SD by sonography in four patients compared with preoperative state, but a 30% decrease was seen in the other two during the follow-up period. Isotope scan showed a functional residual spleen in all six, with no remarkable difference in size 4 years after operation, except in the one who relapsed. The IgM level did not fall significantly after operation, nor did signs of infection develop in any patient.

CONCLUSION

PDAS is a safe and effective mode of therapy in thalassemia major, provided the disease is not advanced and SD does not exceed 11 cm in its greatest diameter.