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Anatomic and Pathologic Computed Tomographic Findings Following Splenectomy
Anatomic and Pathologic Computed Tomographic Findings Following Splenectomy Rivka Zissin, MD,* Mordechai Gutman,† Einat Even-Sapir, MD, PhD,‡ and Gabriela Gayer, MD§ Computed tomography (CT) is frequently used for postoperative evaluation in patients who have undergone splenectomy, on either an elective or an emergency basis. This pictorial article reviews and demonstrates the CT findings of postoperative anatomic changes, as well as various postoperative complications following splenectomy. Semin Ultrasound CT MRI 28:67-78 © 2007 Elsevier Inc. All rights reserved.
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urgical removal of the spleen, splenectomy, is a wellrecognized treatment for various hematologic disorders, as well as for a variety of other clinical situations ranging from emergency splenectomy in trauma, via staging and palliation of extensive malignancies with en-bloc resection of locally advanced adjacent cancer or isolated splenic metastases, to splenectomy performed after inadvertent intraoperative splenic injury.1,2 Postoperative complications may be classified as medical and surgical. The latter are related to the operative procedure and can be classified as early and delayed postoperative complications. Early complications include subphrenic collections, iatrogenic injury to adjacent organs like the pancreas, colon, or stomach, venous thrombosis, and thoracic findings including left lower lobe atelectasis and pleural effusion (Fig 1A).2-4 Delayed postsplenectomy complications include recurrence of a hematologic disease within an accessory spleen or within foci of splenosis.5 Nowadays, computed tomography (CT) provides superb anatomic detail and diagnostic accuracy of various intraabdominal pathological processes, and it thus has become an essential diagnostic tool in the evaluation of postoperative complications. Percutaneous drainage of intraabdominal postoperative collections under CT guidance is another advantage of CT. The radiologist should be familiar with the CT appearance of diverse postoperative abnormalities and insults. Several *Department of Diagnostic Imaging. †Department of Surgery “A” Meir Medical Center, Kfar Saba. ‡Department of Nuclear Medicine, Tel-Aviv Sourasky Medical Center. §Department of Diagnostic Imaging, Assaf Harofe Medical Center, Zerifin, affiliated to the Sackler Faculty of Medicine, Tel-Aviv University, TelAviv, Israel. Address reprint requests to Dr. R. Zissin, Dept. of Diagnostic Imaging, Meir Medical Center, Kfar Saba, 44281, Israel. E-mail: [email protected]
0887-2171/07/$-see front matter © 2007 Elsevier Inc. All rights reserved. doi:10.1053/j.sult.2006.10.009
conditions are potentially life threatening, requiring prompt management, and the correct diagnosis may be crucial.4 In this article we describe the different CT features of a variety of postoperative complications following splenectomy.
Technical Considerations CT Technique Standard abdominal CT scanning for evaluating patients after abdominal surgery is usually obtained following the administration of both orally diluted water-soluble contrast material and intravenous injection of contrast medium with dynamically enhanced scanning of the entire abdomen. Contiguous slices should be performed from the diaphragm to the symphysis pubis, as postoperative complications may be found at a remote site from the surgical field.6 The use of a multislice helical scanner with faster scanning speeds and narrow collimation, with both axial images and multiplanar reformations, results in a high-quality anatomic demonstration (Fig 2).
Normal Postoperative Findings Accumulation of a small amount of a sterile, reactive peritoneal effusion of water density is a common normal finding in the immediate postoperative period (Fig 3). Most of these collections are not encapsulated, confined to the surgical bed, and resolve on follow-up studies with the appearance of an “empty” splenic bed (Fig 4).7 A small amount of left-sided pleural effusion and posterior displacement of the stomach to the subphrenic space is also to be expected. Pneumoperitoneum is another common finding following recent intraabdominal surgery, which usually disappears within days (Fig 3). A persistent or 67
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Figure 1 A 51-year-old man 13 days after subtotal colectomy due to ischemic colitis and 1 day after relaparotomy and splenectomy due to active hemorrhage caused by inadvertent splenic rupture. (A) Contrast-enhanced CT at the lung base shows left-sided pleural effusion and associated left lower lobe atelectasis. (B) Lower down, a left-sided subphrenic abscess, seen as a large fluid collection with air–fluid level (FC). (C, D) Scan following percutaneous drainage of pus: the fluid collection has almost entirely been drained (C). Unfortunately, however, the drain (arrow in “D”) traverses the left lateral pleural recess.
Figure 2 A 48-year-old man with fever after splenectomy. Coronal multiplanar image reconstructed from contrast-enhanced CT data shows a left subphrenic fluid collection (FC) in the splenic bed.
Figure 3 A 73-year-old man 8 days after splenectomy for nonHodgkin’s lymphoma. Contrast-enhanced CT shows a gas bubble (short arrow) and a reactive peritoneal effusion in the splenic bed at the level of a surgical clip (long thin arrow).
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Figure 4 A 73-year-old woman presented with fever and abdominal pain 2 weeks after distal pancreatectomy and splenectomy due to pancreatic cancer. On CT (not shown) a lesser sac abscess was found and successfully drained percutaneously. (A) On contrast-enhanced CT, performed 6 weeks later for follow-up, the “empty” splenic bed is seen, at the upper abdomen, as the normal anatomy after splenectomy. (B) Lower down, a filling defect is seen at the portal vein (black arrow) compatible with clinically unsuspected portal vein thrombosis. A part of the draining catheter is also seen (white arrow).
increasing amount of free air in the peritoneum beyond the first postoperative week, in the absence of an abdominal drain or a dehiscent incision, is suggestive of a perforation of the gastrointestinal tract or, in the appropriate clinical setting, of an anastomotic leak.7,8
Incisional hematomas or seromas are other wound complications seen on CT, as either hyperdense or hypodense fluid collections, respectively, that accumulate at the surgical incision.7
Intraabdominal Abscess
Postoperative Complications Following splenectomy, either open or laparoscopic, various abdominal complications may occur in the early or delayed postoperative period. Such postoperative insults may be divided, by a decreasing order, to technique-related, pulmonary, infectious, and other types of complications.3,4 The complication rate differs significantly in the various indications for the splenectomy, as well as the splenic size. For example, the perioperative complications of splenectomy for hematologic diseases, on the whole, is reported to be about 30%, while splenectomy for hematologic malignancies is reported to be associated with an overall complication rate of up to 52%.3,9 In general, recent studies have reported that laparoscopic splenectomy, although needing more operative time than the open procedure, is associated with a significant reduction in surgery-related morbidity of pulmonary, wound, and infectious complications but has higher frequencies of portosplenic thrombosis and unwanted postoperative residual splenic function.4,10,11
Wound Complications Wound complications include wound infection, which is usually apparent clinically during the second to third postoperative week, but may be seen earlier on CT, as small fluid or gas collections within the abdominal wall incision.7 An untreated infection may further cause wound dehiscence and, later, an incisional abdominal wall hernia.
An intraabdominal abscess remains the main cause of morbidity in the postsplenectomy patient. CT is highly accurate in diagnosing a postoperative abscess and is the preferred imaging modality in assessing its presence, location, and size, and for assessing the presence or absence of a defined wall or internal septations.7 The CT features of an abscess include a well-circumscribed fluid collection, occasionally with a peripheral enhancing rim, with low-attenuation values that may contain gas bubbles (Fig 1B) or an air–fluid level. The abscess may, however, appear as a mass of soft-tissue density within inflamed peritoneal planes displacing adjacent structures. CT-guided diagnostic aspiration of such a fluid collection may be required, as chronic hematoma or pancreatic pseudocysts can have similar features on CT (Figs. 5 and 6). Regarding hematomas, hyperdensity is an important, nearly diagnostic, CT feature of a recent bleed. Over time, resolving hematomas decrease in size along with diminution of their attenuation, often in a centripetal manner leading to the appearance of a lucent halo (Fig 5), sometimes with peripheral rim enhancement following the injection of intravenous contrast.12 CT also plays a therapeutic role by guiding percutaneous drainage of an abscess (Figs. 1C and D and 7) with a high success rate and good long-term results, especially for welldefined unilocular collections, which are located in accessible regions. Nowadays the use of CT guidance for the safe placement of a drainage catheter has revolutionized the surgeon’s approach to postoperative intraabdominal abscesses.
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Figure 6 A 49-year-old man 6 weeks after splenectomy for severe thrombotic thrombocytopenic purpura presented with sepsis. Contrast-enhanced CT demonstrated a large fluid collection (FC) in the left upper quadrant with numerous gas bubbles. On surgery the subphrenic collection proved to be an infected pancreatic pseudocyst.
Figure 5 A 43-year-old man presented with fever, leukocytosis, and hyperbilirubinemia 10 days after splenectomy for blunt abdominal trauma. (A) Non-contrast-enhanced CT at the upper abdomen demonstrates a hyperdense collection with a lucent halo at the splenic bed (arrows) compressing the adjacent gastric wall. A small amount of pleural fluid, probably reactive, is also seen. (B) Contrast-enhanced CT at the level of “A” clearly demonstrates a hypodense rim surrounding the nonenhancing central collection (thin arrows), compatible with a resolving hematoma. A surgical clip is seen (thicker arrow). Fine-needle aspiration of the collection disclosed chronic hematoma and proved to be sterile.
more frequently following laparoscopic splenectomy due to the deleterious effects of pneumoperitoneum on human physiology.10,11 Patients with hemolytic anemia and myeloproliferative disorders are at higher risk, whereas the frequency of portal vein thrombosis in the case of trauma is not well-known. Portomesenteric thrombosis may present clinically with nonspecific complaints, such as fever, abdominal pain and tenderness, nausea/vomiting, and leukocytosis, symptoms that often necessitate a CT study. On contrastenhanced CT of the upper abdomen a filling defect within the portomesenteric vein is diagnostic of venous thrombosis (Figs. 4B and 8). Portal vein thrombosis should be suspected in a patient with fever and/or abdominal pain after splenectomy and an abdominal CT during portal venous phase should be performed. Clinically unrecognized and untreated splenoportal thrombosis may appear later on as cavernous transformation of the portal vein (Fig 9).
Injuries to Adjacent Organs and Structures The advantages of percutaneous over surgical drainage include avoidance of repeat surgery and anesthesia, reduction of costly hospitalization, easier nursing, earlier diagnosis, and treatment with a low recurrence rate.13 However, due to the location of most postsplenectomy collections in the splenic bed and their close proximity to the pleural surface at the lung base, not infrequently the drain will traverse the pleura and a subsequent inadvertent empyema may occur (Figs. 1 and 7).
Portal or Splenic Vein Thrombosis Thrombosis of the portal venous system is an infrequent complication after splenectomy with an incidence of 6.3 to 10% after elective open splenectomy and has been reported
Due to the anatomic relationship between the spleen and the tail of the pancreas, intraoperative manipulation or improper use of electrocautery during splenectomy may lead to direct pancreatic injury and postoperative pancreatitis (Fig 10A) that may become complicated with pseudocyst formation (Fig 6).3,4 Gastric injury is another complication following splenectomy with a high mortality rate. It may be caused during dissecting and ligating of the short gastric vessels in the splenogastric ligament, which are in close contact with the upper gastric wall, by inadvertent direct injury to the gastric wall or related to mural necrosis.14 On CT, gastric wall injury and perforation present as a localized fluid collection with gas bubbles and/or the orally ingested contrast in
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Figure 7 A 50-year-old woman with fever and leukocytosis 3 weeks after distal pancreatectomy, splenectomy, and partial gastrectomy for gastric stromal tumor. (A) Contrast-enhanced CT demonstrates an anterior subphrenic fluid collection (FC) with air–fluid level and a small amount of left-sided pleural effusion (arrow). The fluid proved to be an abscess on percutaneous drainage. (B, C) Contrastenhanced CT performed for clinical deterioration, after inserting a percutaneous drain (arrow) into the abscess, shows that the subphrenic abscess has almost completely been drained (arrow in “C”). However, a large pleural effusion has appeared (E), which proved to be an empyema, probably related to the transdiaphragmatic route (arrow in “B”) of the percutaneous drain.
the splenic bed (Figs. 10 and 11), or with a large hydropneumoperitoneum. Inadvertent injury to the adjacent colon, although rare, is another possible complication leading to a leak of colonic contents and subsequent peritonitis with significant morbidity and mortality.
Splenosis Splenosis is defined as autotransplantation of splenic tissue in various abnormal sites after splenic injury that can be either traumatic or iatrogenic during surgery. Iatrogenic splenosis occurs more commonly during laparoscopic splenectomy, mainly in resection of an enlarged spleen with frail parenchyma which has an increased risk of parenchymal rupture and cell spillage.5 Abdominal splenosis is the most common form (Figs. 12 and 13) and has usually no clinical significance. It may, however, simulate intraabdominal tumoral implants, present with bowel obstruction or massive gastrointestinal hemorrhage due to small bowel involvement, or cause a relapse of hematological disorders.15,16 Thoracic splenosis is less common, usually occurring following traumatic injury to both the spleen and the diaphragm, and leading to the formation of left-sided, pleural-based pulmonary nodules
or masses (Fig 14).17 Splenosis has also been rarely reported in the subcutis, along sites of incisional scar or penetrating wound (Figs. 13 and 15).18 The diagnosis of splenosis can be confirmed noninvasively by nuclear scintigraphy. Selective scintigraphy studies with radiolabeled heat-damaged RBCs appear to be more sensitive than by technetium-99m sulfur-colloid (Fig 16) for accurate depiction of functioning splenic tissue foci as small as 2 cm or smaller when using SPECT technology.15,19 Recently, a more conservative, nonsurgical management in traumatic splenic injury, even with a grossly ruptured spleen, has been introduced. The incidence of implants of splenosis in these cases, even when the spleen remains in situ, will eventually increase and awareness of this entity is important.16
Residual Splenic Function Following Splenectomy An unidentified accessory spleen, ectopic splenic tissue in the abdominal cavity with a reported incidence of 10 to 30% in the general population, which was left in situ, or accidental or intentional splenic auto-implants may preserve residual splenic function following splenectomy.5,18
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Figure 8 A 49-year-old woman presented with fever 10 days after laparoscopic splenectomy. (A) Contrast-enhanced CT at the level of the porta hepatis demonstrates intrahepatic branching filling defects (black arrows) compatible with thrombosed portal veins. White arrow shows the surgical clip at the splenic bed. (B) Lower down the thrombosed main portal vein is seen (black arrow) as well as the subcutaneous signs of the recent surgery (white arrow). (C) More caudally the thrombosed mesenteric vein is seen (arrow).
Such residual functioning splenic tissue helps in preserving the host defense mechanism. However, when splenectomy was performed for the management of a hematologic disease, such residual splenic function may induce relapse of the hematologic disorders and is considered a failure of the surgical treatment. It can happen due either to unrecognized accessory spleens, left within the abdomen, or to accidental parenchymal injury and cell spillage during the operation. The latter possibility seems to occur more frequently during laparoscopic splenectomy.5 The functioning splenic tissue can be confirmed with scintigraphy, mainly radiolabeled heat-damaged RBC study and localized by abdominal CT. Adequate demonstration of the residual splenic tissue in both studies is required before repeat surgery is performed.15,18
Conclusion Various abnormal findings can be well demonstrated on abdominal CT following splenectomy, either open or laparoscopic. The radiologist plays an important role in their diagnosis, and familiarity with the imaging features on CT, coupled with knowledge of the clinical settings, should lead
to an early recognition of postoperative complications and their management.
Acknowledgment We gratefully acknowledge Marjorie Hertz, MD, for her assistance in the preparation of the manuscript.
References 1. Fraker DL: Spleen, in Greenfield LJ (ed): Surgery Scientific Principles and Practice (ed 3). Philadelphia, PA, Lippincott Williams & Wilkins, 2001, pp 1236-1259 2. Katkhouda N, Hurwitz MB, Rivera RT, et al: Laparoscopic splenectomy: outcome and efficacy in 103 consecutive patients. Ann Surg 228:568578, 1998 3. Horowitz J, Smith JL, Weber TK, et al: Postoperative complications after splenectomy for hematologic malignancies. Ann Surg 223:290296, 1996 4. Targarona EM, Espert JJ, Bombuy E, et al: Complications of laparoscopic splenectomy. Arch Surg 135:1137-1140, 2000 5. Targarona EM, Espert JJ, Balague C, et al: Residual splenic function after laparoscopic splenectomy: a clinical concern. Arch Surg 133:5660, 1998 6. Krumenacker JH, Panicek DM, Ginsberg MS, et al: CT in searching for abscess after abdominal or pelvic surgery in patients with neoplasia: do abdomen and pelvis both need to be scanned? J Comput Assist Tomogr 21:652-655, 1997
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73 7. Ghahremani GG, Gore RM: CT diagnosis of postoperative abdominal complications. Radiol Clin North Am 27:787-804, 1989 8. Gayer G, Hertz M, Zissin R: Postoperative pneumoperitoneum: prevalence, duration, and possible significance. Semin Ultrasound CT MR 25:286-289, 2004 9. Mittelman M, Kyzer S, Zeidman A, et al: Splenectomy for haematological diseases—a single institution experience. Haematologia 28:185198, 1997 10. Winslow ER, Brunt LM: Perioperative outcomes of laparoscopic versus open splenectomy: a meta-analysis with an emphasis on complications. Surgery 134:647-653, 2003 11. Ikeda M, Sekimoto M, Kubota M, et al: High incidence of thrombosis of the portal venous system after laparoscopic splenectomy: a prospective study with contrast-enhanced CT scan. Ann Surg 241:208-216, 2005 12. Zissin R, Ellis M, Gayer G: The CT findings of abdominal anticoagulantrelated hematomas. Semin Ultrasound CT MR 27:117-225, 2006 13. Betsch A, Wiskirchen J, Trubenbach J, et al: CT-guided percutaneous drainage of intra-abdominal abscesses: APACHE III score stratification of 1-year results. Eur Radiol 12:2883-2889, 2002 14. Martinez CA, Waisberg J, Palma RT, et al: Gastric necrosis and perforation as a complication of splenectomy. Case report and related references. Ar Qgastroenterol 37:227-230, 2000 15. Schenkein DP, Ahmed E: Case records of the Massachusetts General Hospital. Weekly clinicopathological exercises. Case 29-1995. A 65year-old man with mediastinal Hodgkin’s disease and a pelvic mass. N Engl J Med 333:784-791, 1995 16. Khosravi MR, Margulies DR, Alsabeh R, et al: Consider the diagnosis of splenosis for soft tissue masses long after any splenic injury. Am Surg 70:967-970, 2004 17. Osadchy A, Zissin R, Shapiro-Feinberg M: Thoracic splenosis. Isr Med Assoc J 3:547, 2001 18. Baack BR, Varsa EW, Burgdorf WH, et al: A report of subcutaneous involvement. Am J Dermatopathol 12:585-588, 1990 19. Sharma R, Mondal A, Kashyap R, et al: Radiolabeled denatured RBC scintigraphy in autologous splenic transplantation. Clin Nucl Med 21: 534-536, 1996
Figure 9 A 33-year-old man years after traumatic splenectomy was examined for left hydronephrosis. (A) Contrast-enhanced CT at the upper abdomen shows numerous collateral vessels at the porta hepatis around a previously thrombosed portal vein (arrows), cavernous transportation of the portal vein. (B) Coronal multiplanar image reconstruction clearly shows the venous collateral circulation of the portal vein (arrows) as well as the absent spleen.
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Figure 10 A 48-year-old woman with fever 8 days after laparoscopic, converted to open, splenectomy for chronic lymphatic leukemia. (A) The pancreatic tail is enlarged (white arrows) with peripancreatic fluid. The abdominal wall sutures of the recent laparotomy and free peritoneal air are seen (black arrows). (B) More cranially, fluid collection (FC) is seen in the splenic bed, posterior to the stomach (S), as well as, probably more than expected, free peritoneal air (arrows). (C, D) Slightly cranial to “B”, at abdominal and lung window settings, respectively, leakage of the oral contrast (thick arrow) from the greater curvature of the neighboring stomach (S) is seen, associated with extraluminal air (thin arrow). Based on clinical grounds, the patient was treated conservatively by percutaneous drainage of the fluid, which proved to be sterile, bloody fluid. A diagnosis of a sealed-off perforation was made as on a repeat scan (not shown), 4 days later, and no extravasation of the oral contrast was demonstrated.
CT findings following splenectomy
Figure 11 A 72-year-old man was examined for pyrexia and leukocytosis 4 days after laparoscopic splenectomy for non-Hodgkin lymphoma. Contrast-enhanced CT at the upper abdomen shows a fluid collection at the splenic bed containing the orally ingested contrast (thick arrow) and extraluminal gas (thin arrows) diagnostic of an inadvertent gastric wall perforation. Note the subcutaneous air indicating the recent laparoscopic procedure.
Figure 12 A 33-year-old woman was referred to CT for evaluation of pelvic masses detected on a gynecological ultrasound study. (A) Contrast-enhanced CT at the upper abdomen shows numerous soft-tissue nodules (arrows) in the splenic bed compatible with foci of splenosis. (B) At the pelvis, at least three soft-tissue nodules are seen (arrows) between the uterus (U) and the rectum. (C) Posterior image of Tc sulfur-colloid liver spleen scintigraphy shows absence of the spleen and uptake of tracer in two pelvic implants (thin arrows). Thicker arrow indicates the urinary bladder.
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Figure 13 An asymptomatic 64-year-old man after traumatic splenectomy. (A, B) Contrast-enhanced CT at the upper abdomen shows numerous intraabdominal and subcutaneous nodules of soft-tissue density (arrows), compatible with implants of splenosis.
Figure 14 A 43-year-old asymptomatic woman 12 years after traumatic splenectomy was referred to CT to evaluate a lung nodule seen on cheat radiograph. (Printed with permission from Ref. 17.) (A, B) CT at the lower chest demonstrates three subpleural nodules of soft-tissue density (thicker arrows), adjacent to ribs deformed by healed fractures (thin arrow). (C) Posterior image of Tc sulfur-colloid liver spleen scintigraphy shows absence of the spleen and uptake of tracer material in three thoracic implants (arrows).
CT findings following splenectomy
Figure 15 A 45-year-old man, 27 years after traumatic splenectomy and nephrectomy and 2 years after colectomy for colonic carcinoma, was examined for suspected abdominal wall splenosis on MRI (not shown). (A, B) SPECT–CT images with radiolabeled denatured RBC (from left to right, above: low-dose CT and SPECT; below: fused and MIP images) show foci of splenosis at the splenic bed (arrowhead) and within the abdominal wall (arrows). L, liver.
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Figure 16 A 51-year-old woman after splenectomy with suspected splenosis on CT (not shown). (A) Planar images of radiolabeled heat-damaged RBC imaging (from left to right, above: AP and PA views; below: oblique and lateral views) show functioning splenic tissue in the left upper abdomen (arrows) compatible with splenosis. (B) SPECT images (from left to right, above: transaxial and sagittal images; below: coronal view) localizes the splenosis (arrows).
S
urgical removal of the spleen, splenectomy, is a wellrecognized treatment for various hematologic disorders, as well as for a variety of other clinical situations ranging from emergency splenectomy in trauma, via staging and palliation of extensive malignancies with en-bloc resection of locally advanced adjacent cancer or isolated splenic metastases, to splenectomy performed after inadvertent intraoperative splenic injury.1,2 Postoperative complications may be classified as medical and surgical. The latter are related to the operative procedure and can be classified as early and delayed postoperative complications. Early complications include subphrenic collections, iatrogenic injury to adjacent organs like the pancreas, colon, or stomach, venous thrombosis, and thoracic findings including left lower lobe atelectasis and pleural effusion (Fig 1A).2-4 Delayed postsplenectomy complications include recurrence of a hematologic disease within an accessory spleen or within foci of splenosis.5 Nowadays, computed tomography (CT) provides superb anatomic detail and diagnostic accuracy of various intraabdominal pathological processes, and it thus has become an essential diagnostic tool in the evaluation of postoperative complications. Percutaneous drainage of intraabdominal postoperative collections under CT guidance is another advantage of CT. The radiologist should be familiar with the CT appearance of diverse postoperative abnormalities and insults. Several *Department of Diagnostic Imaging. †Department of Surgery “A” Meir Medical Center, Kfar Saba. ‡Department of Nuclear Medicine, Tel-Aviv Sourasky Medical Center. §Department of Diagnostic Imaging, Assaf Harofe Medical Center, Zerifin, affiliated to the Sackler Faculty of Medicine, Tel-Aviv University, TelAviv, Israel. Address reprint requests to Dr. R. Zissin, Dept. of Diagnostic Imaging, Meir Medical Center, Kfar Saba, 44281, Israel. E-mail: [email protected]
0887-2171/07/$-see front matter © 2007 Elsevier Inc. All rights reserved. doi:10.1053/j.sult.2006.10.009
conditions are potentially life threatening, requiring prompt management, and the correct diagnosis may be crucial.4 In this article we describe the different CT features of a variety of postoperative complications following splenectomy.
Technical Considerations CT Technique Standard abdominal CT scanning for evaluating patients after abdominal surgery is usually obtained following the administration of both orally diluted water-soluble contrast material and intravenous injection of contrast medium with dynamically enhanced scanning of the entire abdomen. Contiguous slices should be performed from the diaphragm to the symphysis pubis, as postoperative complications may be found at a remote site from the surgical field.6 The use of a multislice helical scanner with faster scanning speeds and narrow collimation, with both axial images and multiplanar reformations, results in a high-quality anatomic demonstration (Fig 2).
Normal Postoperative Findings Accumulation of a small amount of a sterile, reactive peritoneal effusion of water density is a common normal finding in the immediate postoperative period (Fig 3). Most of these collections are not encapsulated, confined to the surgical bed, and resolve on follow-up studies with the appearance of an “empty” splenic bed (Fig 4).7 A small amount of left-sided pleural effusion and posterior displacement of the stomach to the subphrenic space is also to be expected. Pneumoperitoneum is another common finding following recent intraabdominal surgery, which usually disappears within days (Fig 3). A persistent or 67
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Figure 1 A 51-year-old man 13 days after subtotal colectomy due to ischemic colitis and 1 day after relaparotomy and splenectomy due to active hemorrhage caused by inadvertent splenic rupture. (A) Contrast-enhanced CT at the lung base shows left-sided pleural effusion and associated left lower lobe atelectasis. (B) Lower down, a left-sided subphrenic abscess, seen as a large fluid collection with air–fluid level (FC). (C, D) Scan following percutaneous drainage of pus: the fluid collection has almost entirely been drained (C). Unfortunately, however, the drain (arrow in “D”) traverses the left lateral pleural recess.
Figure 2 A 48-year-old man with fever after splenectomy. Coronal multiplanar image reconstructed from contrast-enhanced CT data shows a left subphrenic fluid collection (FC) in the splenic bed.
Figure 3 A 73-year-old man 8 days after splenectomy for nonHodgkin’s lymphoma. Contrast-enhanced CT shows a gas bubble (short arrow) and a reactive peritoneal effusion in the splenic bed at the level of a surgical clip (long thin arrow).
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Figure 4 A 73-year-old woman presented with fever and abdominal pain 2 weeks after distal pancreatectomy and splenectomy due to pancreatic cancer. On CT (not shown) a lesser sac abscess was found and successfully drained percutaneously. (A) On contrast-enhanced CT, performed 6 weeks later for follow-up, the “empty” splenic bed is seen, at the upper abdomen, as the normal anatomy after splenectomy. (B) Lower down, a filling defect is seen at the portal vein (black arrow) compatible with clinically unsuspected portal vein thrombosis. A part of the draining catheter is also seen (white arrow).
increasing amount of free air in the peritoneum beyond the first postoperative week, in the absence of an abdominal drain or a dehiscent incision, is suggestive of a perforation of the gastrointestinal tract or, in the appropriate clinical setting, of an anastomotic leak.7,8
Incisional hematomas or seromas are other wound complications seen on CT, as either hyperdense or hypodense fluid collections, respectively, that accumulate at the surgical incision.7
Intraabdominal Abscess
Postoperative Complications Following splenectomy, either open or laparoscopic, various abdominal complications may occur in the early or delayed postoperative period. Such postoperative insults may be divided, by a decreasing order, to technique-related, pulmonary, infectious, and other types of complications.3,4 The complication rate differs significantly in the various indications for the splenectomy, as well as the splenic size. For example, the perioperative complications of splenectomy for hematologic diseases, on the whole, is reported to be about 30%, while splenectomy for hematologic malignancies is reported to be associated with an overall complication rate of up to 52%.3,9 In general, recent studies have reported that laparoscopic splenectomy, although needing more operative time than the open procedure, is associated with a significant reduction in surgery-related morbidity of pulmonary, wound, and infectious complications but has higher frequencies of portosplenic thrombosis and unwanted postoperative residual splenic function.4,10,11
Wound Complications Wound complications include wound infection, which is usually apparent clinically during the second to third postoperative week, but may be seen earlier on CT, as small fluid or gas collections within the abdominal wall incision.7 An untreated infection may further cause wound dehiscence and, later, an incisional abdominal wall hernia.
An intraabdominal abscess remains the main cause of morbidity in the postsplenectomy patient. CT is highly accurate in diagnosing a postoperative abscess and is the preferred imaging modality in assessing its presence, location, and size, and for assessing the presence or absence of a defined wall or internal septations.7 The CT features of an abscess include a well-circumscribed fluid collection, occasionally with a peripheral enhancing rim, with low-attenuation values that may contain gas bubbles (Fig 1B) or an air–fluid level. The abscess may, however, appear as a mass of soft-tissue density within inflamed peritoneal planes displacing adjacent structures. CT-guided diagnostic aspiration of such a fluid collection may be required, as chronic hematoma or pancreatic pseudocysts can have similar features on CT (Figs. 5 and 6). Regarding hematomas, hyperdensity is an important, nearly diagnostic, CT feature of a recent bleed. Over time, resolving hematomas decrease in size along with diminution of their attenuation, often in a centripetal manner leading to the appearance of a lucent halo (Fig 5), sometimes with peripheral rim enhancement following the injection of intravenous contrast.12 CT also plays a therapeutic role by guiding percutaneous drainage of an abscess (Figs. 1C and D and 7) with a high success rate and good long-term results, especially for welldefined unilocular collections, which are located in accessible regions. Nowadays the use of CT guidance for the safe placement of a drainage catheter has revolutionized the surgeon’s approach to postoperative intraabdominal abscesses.
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Figure 6 A 49-year-old man 6 weeks after splenectomy for severe thrombotic thrombocytopenic purpura presented with sepsis. Contrast-enhanced CT demonstrated a large fluid collection (FC) in the left upper quadrant with numerous gas bubbles. On surgery the subphrenic collection proved to be an infected pancreatic pseudocyst.
Figure 5 A 43-year-old man presented with fever, leukocytosis, and hyperbilirubinemia 10 days after splenectomy for blunt abdominal trauma. (A) Non-contrast-enhanced CT at the upper abdomen demonstrates a hyperdense collection with a lucent halo at the splenic bed (arrows) compressing the adjacent gastric wall. A small amount of pleural fluid, probably reactive, is also seen. (B) Contrast-enhanced CT at the level of “A” clearly demonstrates a hypodense rim surrounding the nonenhancing central collection (thin arrows), compatible with a resolving hematoma. A surgical clip is seen (thicker arrow). Fine-needle aspiration of the collection disclosed chronic hematoma and proved to be sterile.
more frequently following laparoscopic splenectomy due to the deleterious effects of pneumoperitoneum on human physiology.10,11 Patients with hemolytic anemia and myeloproliferative disorders are at higher risk, whereas the frequency of portal vein thrombosis in the case of trauma is not well-known. Portomesenteric thrombosis may present clinically with nonspecific complaints, such as fever, abdominal pain and tenderness, nausea/vomiting, and leukocytosis, symptoms that often necessitate a CT study. On contrastenhanced CT of the upper abdomen a filling defect within the portomesenteric vein is diagnostic of venous thrombosis (Figs. 4B and 8). Portal vein thrombosis should be suspected in a patient with fever and/or abdominal pain after splenectomy and an abdominal CT during portal venous phase should be performed. Clinically unrecognized and untreated splenoportal thrombosis may appear later on as cavernous transformation of the portal vein (Fig 9).
Injuries to Adjacent Organs and Structures The advantages of percutaneous over surgical drainage include avoidance of repeat surgery and anesthesia, reduction of costly hospitalization, easier nursing, earlier diagnosis, and treatment with a low recurrence rate.13 However, due to the location of most postsplenectomy collections in the splenic bed and their close proximity to the pleural surface at the lung base, not infrequently the drain will traverse the pleura and a subsequent inadvertent empyema may occur (Figs. 1 and 7).
Portal or Splenic Vein Thrombosis Thrombosis of the portal venous system is an infrequent complication after splenectomy with an incidence of 6.3 to 10% after elective open splenectomy and has been reported
Due to the anatomic relationship between the spleen and the tail of the pancreas, intraoperative manipulation or improper use of electrocautery during splenectomy may lead to direct pancreatic injury and postoperative pancreatitis (Fig 10A) that may become complicated with pseudocyst formation (Fig 6).3,4 Gastric injury is another complication following splenectomy with a high mortality rate. It may be caused during dissecting and ligating of the short gastric vessels in the splenogastric ligament, which are in close contact with the upper gastric wall, by inadvertent direct injury to the gastric wall or related to mural necrosis.14 On CT, gastric wall injury and perforation present as a localized fluid collection with gas bubbles and/or the orally ingested contrast in
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Figure 7 A 50-year-old woman with fever and leukocytosis 3 weeks after distal pancreatectomy, splenectomy, and partial gastrectomy for gastric stromal tumor. (A) Contrast-enhanced CT demonstrates an anterior subphrenic fluid collection (FC) with air–fluid level and a small amount of left-sided pleural effusion (arrow). The fluid proved to be an abscess on percutaneous drainage. (B, C) Contrastenhanced CT performed for clinical deterioration, after inserting a percutaneous drain (arrow) into the abscess, shows that the subphrenic abscess has almost completely been drained (arrow in “C”). However, a large pleural effusion has appeared (E), which proved to be an empyema, probably related to the transdiaphragmatic route (arrow in “B”) of the percutaneous drain.
the splenic bed (Figs. 10 and 11), or with a large hydropneumoperitoneum. Inadvertent injury to the adjacent colon, although rare, is another possible complication leading to a leak of colonic contents and subsequent peritonitis with significant morbidity and mortality.
Splenosis Splenosis is defined as autotransplantation of splenic tissue in various abnormal sites after splenic injury that can be either traumatic or iatrogenic during surgery. Iatrogenic splenosis occurs more commonly during laparoscopic splenectomy, mainly in resection of an enlarged spleen with frail parenchyma which has an increased risk of parenchymal rupture and cell spillage.5 Abdominal splenosis is the most common form (Figs. 12 and 13) and has usually no clinical significance. It may, however, simulate intraabdominal tumoral implants, present with bowel obstruction or massive gastrointestinal hemorrhage due to small bowel involvement, or cause a relapse of hematological disorders.15,16 Thoracic splenosis is less common, usually occurring following traumatic injury to both the spleen and the diaphragm, and leading to the formation of left-sided, pleural-based pulmonary nodules
or masses (Fig 14).17 Splenosis has also been rarely reported in the subcutis, along sites of incisional scar or penetrating wound (Figs. 13 and 15).18 The diagnosis of splenosis can be confirmed noninvasively by nuclear scintigraphy. Selective scintigraphy studies with radiolabeled heat-damaged RBCs appear to be more sensitive than by technetium-99m sulfur-colloid (Fig 16) for accurate depiction of functioning splenic tissue foci as small as 2 cm or smaller when using SPECT technology.15,19 Recently, a more conservative, nonsurgical management in traumatic splenic injury, even with a grossly ruptured spleen, has been introduced. The incidence of implants of splenosis in these cases, even when the spleen remains in situ, will eventually increase and awareness of this entity is important.16
Residual Splenic Function Following Splenectomy An unidentified accessory spleen, ectopic splenic tissue in the abdominal cavity with a reported incidence of 10 to 30% in the general population, which was left in situ, or accidental or intentional splenic auto-implants may preserve residual splenic function following splenectomy.5,18
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Figure 8 A 49-year-old woman presented with fever 10 days after laparoscopic splenectomy. (A) Contrast-enhanced CT at the level of the porta hepatis demonstrates intrahepatic branching filling defects (black arrows) compatible with thrombosed portal veins. White arrow shows the surgical clip at the splenic bed. (B) Lower down the thrombosed main portal vein is seen (black arrow) as well as the subcutaneous signs of the recent surgery (white arrow). (C) More caudally the thrombosed mesenteric vein is seen (arrow).
Such residual functioning splenic tissue helps in preserving the host defense mechanism. However, when splenectomy was performed for the management of a hematologic disease, such residual splenic function may induce relapse of the hematologic disorders and is considered a failure of the surgical treatment. It can happen due either to unrecognized accessory spleens, left within the abdomen, or to accidental parenchymal injury and cell spillage during the operation. The latter possibility seems to occur more frequently during laparoscopic splenectomy.5 The functioning splenic tissue can be confirmed with scintigraphy, mainly radiolabeled heat-damaged RBC study and localized by abdominal CT. Adequate demonstration of the residual splenic tissue in both studies is required before repeat surgery is performed.15,18
Conclusion Various abnormal findings can be well demonstrated on abdominal CT following splenectomy, either open or laparoscopic. The radiologist plays an important role in their diagnosis, and familiarity with the imaging features on CT, coupled with knowledge of the clinical settings, should lead
to an early recognition of postoperative complications and their management.
Acknowledgment We gratefully acknowledge Marjorie Hertz, MD, for her assistance in the preparation of the manuscript.
References 1. Fraker DL: Spleen, in Greenfield LJ (ed): Surgery Scientific Principles and Practice (ed 3). Philadelphia, PA, Lippincott Williams & Wilkins, 2001, pp 1236-1259 2. Katkhouda N, Hurwitz MB, Rivera RT, et al: Laparoscopic splenectomy: outcome and efficacy in 103 consecutive patients. Ann Surg 228:568578, 1998 3. Horowitz J, Smith JL, Weber TK, et al: Postoperative complications after splenectomy for hematologic malignancies. Ann Surg 223:290296, 1996 4. Targarona EM, Espert JJ, Bombuy E, et al: Complications of laparoscopic splenectomy. Arch Surg 135:1137-1140, 2000 5. Targarona EM, Espert JJ, Balague C, et al: Residual splenic function after laparoscopic splenectomy: a clinical concern. Arch Surg 133:5660, 1998 6. Krumenacker JH, Panicek DM, Ginsberg MS, et al: CT in searching for abscess after abdominal or pelvic surgery in patients with neoplasia: do abdomen and pelvis both need to be scanned? J Comput Assist Tomogr 21:652-655, 1997
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73 7. Ghahremani GG, Gore RM: CT diagnosis of postoperative abdominal complications. Radiol Clin North Am 27:787-804, 1989 8. Gayer G, Hertz M, Zissin R: Postoperative pneumoperitoneum: prevalence, duration, and possible significance. Semin Ultrasound CT MR 25:286-289, 2004 9. Mittelman M, Kyzer S, Zeidman A, et al: Splenectomy for haematological diseases—a single institution experience. Haematologia 28:185198, 1997 10. Winslow ER, Brunt LM: Perioperative outcomes of laparoscopic versus open splenectomy: a meta-analysis with an emphasis on complications. Surgery 134:647-653, 2003 11. Ikeda M, Sekimoto M, Kubota M, et al: High incidence of thrombosis of the portal venous system after laparoscopic splenectomy: a prospective study with contrast-enhanced CT scan. Ann Surg 241:208-216, 2005 12. Zissin R, Ellis M, Gayer G: The CT findings of abdominal anticoagulantrelated hematomas. Semin Ultrasound CT MR 27:117-225, 2006 13. Betsch A, Wiskirchen J, Trubenbach J, et al: CT-guided percutaneous drainage of intra-abdominal abscesses: APACHE III score stratification of 1-year results. Eur Radiol 12:2883-2889, 2002 14. Martinez CA, Waisberg J, Palma RT, et al: Gastric necrosis and perforation as a complication of splenectomy. Case report and related references. Ar Qgastroenterol 37:227-230, 2000 15. Schenkein DP, Ahmed E: Case records of the Massachusetts General Hospital. Weekly clinicopathological exercises. Case 29-1995. A 65year-old man with mediastinal Hodgkin’s disease and a pelvic mass. N Engl J Med 333:784-791, 1995 16. Khosravi MR, Margulies DR, Alsabeh R, et al: Consider the diagnosis of splenosis for soft tissue masses long after any splenic injury. Am Surg 70:967-970, 2004 17. Osadchy A, Zissin R, Shapiro-Feinberg M: Thoracic splenosis. Isr Med Assoc J 3:547, 2001 18. Baack BR, Varsa EW, Burgdorf WH, et al: A report of subcutaneous involvement. Am J Dermatopathol 12:585-588, 1990 19. Sharma R, Mondal A, Kashyap R, et al: Radiolabeled denatured RBC scintigraphy in autologous splenic transplantation. Clin Nucl Med 21: 534-536, 1996
Figure 9 A 33-year-old man years after traumatic splenectomy was examined for left hydronephrosis. (A) Contrast-enhanced CT at the upper abdomen shows numerous collateral vessels at the porta hepatis around a previously thrombosed portal vein (arrows), cavernous transportation of the portal vein. (B) Coronal multiplanar image reconstruction clearly shows the venous collateral circulation of the portal vein (arrows) as well as the absent spleen.
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Figure 10 A 48-year-old woman with fever 8 days after laparoscopic, converted to open, splenectomy for chronic lymphatic leukemia. (A) The pancreatic tail is enlarged (white arrows) with peripancreatic fluid. The abdominal wall sutures of the recent laparotomy and free peritoneal air are seen (black arrows). (B) More cranially, fluid collection (FC) is seen in the splenic bed, posterior to the stomach (S), as well as, probably more than expected, free peritoneal air (arrows). (C, D) Slightly cranial to “B”, at abdominal and lung window settings, respectively, leakage of the oral contrast (thick arrow) from the greater curvature of the neighboring stomach (S) is seen, associated with extraluminal air (thin arrow). Based on clinical grounds, the patient was treated conservatively by percutaneous drainage of the fluid, which proved to be sterile, bloody fluid. A diagnosis of a sealed-off perforation was made as on a repeat scan (not shown), 4 days later, and no extravasation of the oral contrast was demonstrated.
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Figure 11 A 72-year-old man was examined for pyrexia and leukocytosis 4 days after laparoscopic splenectomy for non-Hodgkin lymphoma. Contrast-enhanced CT at the upper abdomen shows a fluid collection at the splenic bed containing the orally ingested contrast (thick arrow) and extraluminal gas (thin arrows) diagnostic of an inadvertent gastric wall perforation. Note the subcutaneous air indicating the recent laparoscopic procedure.
Figure 12 A 33-year-old woman was referred to CT for evaluation of pelvic masses detected on a gynecological ultrasound study. (A) Contrast-enhanced CT at the upper abdomen shows numerous soft-tissue nodules (arrows) in the splenic bed compatible with foci of splenosis. (B) At the pelvis, at least three soft-tissue nodules are seen (arrows) between the uterus (U) and the rectum. (C) Posterior image of Tc sulfur-colloid liver spleen scintigraphy shows absence of the spleen and uptake of tracer in two pelvic implants (thin arrows). Thicker arrow indicates the urinary bladder.
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Figure 13 An asymptomatic 64-year-old man after traumatic splenectomy. (A, B) Contrast-enhanced CT at the upper abdomen shows numerous intraabdominal and subcutaneous nodules of soft-tissue density (arrows), compatible with implants of splenosis.
Figure 14 A 43-year-old asymptomatic woman 12 years after traumatic splenectomy was referred to CT to evaluate a lung nodule seen on cheat radiograph. (Printed with permission from Ref. 17.) (A, B) CT at the lower chest demonstrates three subpleural nodules of soft-tissue density (thicker arrows), adjacent to ribs deformed by healed fractures (thin arrow). (C) Posterior image of Tc sulfur-colloid liver spleen scintigraphy shows absence of the spleen and uptake of tracer material in three thoracic implants (arrows).
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Figure 15 A 45-year-old man, 27 years after traumatic splenectomy and nephrectomy and 2 years after colectomy for colonic carcinoma, was examined for suspected abdominal wall splenosis on MRI (not shown). (A, B) SPECT–CT images with radiolabeled denatured RBC (from left to right, above: low-dose CT and SPECT; below: fused and MIP images) show foci of splenosis at the splenic bed (arrowhead) and within the abdominal wall (arrows). L, liver.
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Figure 16 A 51-year-old woman after splenectomy with suspected splenosis on CT (not shown). (A) Planar images of radiolabeled heat-damaged RBC imaging (from left to right, above: AP and PA views; below: oblique and lateral views) show functioning splenic tissue in the left upper abdomen (arrows) compatible with splenosis. (B) SPECT images (from left to right, above: transaxial and sagittal images; below: coronal view) localizes the splenosis (arrows).