Management of splenic injury in the adult trauma patient

INTRODUCTION — The spleen is one of the commonly injured intra-abdominal organs. The diagnosis and prompt management of potentially life-threatening hemorrhage is the primary goal. The preservation of functional splenic tissue is secondary and in selected patients can be accomplished using nonoperative management or operative salvage techniques. Any attempt to salvage the spleen is abandoned in the face of ongoing hemorrhage or other life-threatening injuries. Emergency and urgent splenectomy remains a life-saving measure for many patients.

This topic will discuss the diagnosis and management of splenic injury. The management of spontaneous splenic rupture related to infectious or hematologic diseases as opposed to injury is discussed separately. (See "Splenomegaly and other splenic disorders in adults", section on 'Trauma/rupture'.)

SPLENIC ANATOMY AND PHYSIOLOGY — The spleen is located posterolaterally in the left upper quadrant of the abdomen beneath the left hemidiaphragm and lateral to the greater curvature of the stomach. The gross anatomy of the spleen is described elsewhere. (See "Surgical management of splenic injury in the adult trauma patient", section on 'Anatomy of the spleen'.)

The spleen is a major lymphopoietic organ, comprising approximately 25 percent of the total lymphoid mass of the body. Normal splenic function is important for the opsonization of encapsulated organisms. Splenic physiology is discussed in detail elsewhere. (See "Splenomegaly and other splenic disorders in adults", section on 'Properties of the normal spleen'.)

MECHANISM OF INJURY — Splenic injury most commonly occurs following blunt trauma due to motor vehicle collisions (driver, passenger, or pedestrian). However, blunt splenic injury can also result from falls, sports-related activities, or assaults [1]. Penetrating splenic trauma is less common compared with blunt injury and is typically due to assault, but inadvertent impalement may also occur. Assault with a knife compared with gunshot or shotgun wounds is less likely to result in penetrating injury due to the spleen's protected location. Nevertheless, deep inspiration can displace the spleen to a more subcostal position, making it more vulnerable. Splenomegaly can also increase the risk of traumatic injury and rupture.

Iatrogenic traumatic injuries to the spleen can result from surgical or endoscopic manipulation of the colon, stomach, pancreas, kidney, or with exposure and reconstruction of the proximal abdominal aorta [2-4]. Most commonly, the primary mechanism is capsular tear, laceration from retraction devices, or tension on the spleen during manipulation of the colon [5]. The risk is greatest for patients undergoing colon resection. A study from the National Inpatient Sample (NIS) database found, among nearly a million patients, a 1 percent incidence of splenic injury during colorectal surgery [6]. Transverse colectomy was the colon procedure most commonly associated with splenic injury. Other factors related to iatrogenic splenic injury include prior surgery, obesity, malignancy, diverticulitis, and peripheral artery disease [4,6].

TRAUMA EVALUATION — We perform initial resuscitation, diagnostic evaluation, and management of the trauma patient with blunt or penetrating trauma based upon protocols from the Advanced Trauma Life Support (ATLS) program, established by the American College of Surgeons Committee on Trauma. The initial resuscitation and evaluation of the patient with blunt or penetrating abdominal or thoracic trauma is discussed in detail elsewhere.

●(See "Initial evaluation and management of blunt abdominal trauma in adults".)

●(See "Initial evaluation and management of abdominal gunshot wounds in adults".)

●(See "Initial evaluation and management of abdominal stab wounds in adults".)

●(See "Initial evaluation and management of blunt thoracic trauma in adults".)

The spleen and liver are the most commonly injured intra-abdominal organs following blunt trauma. In up to 60 percent of patients, the spleen is the only organ injured [7]. Specific elements of the history, physical examination, and diagnostic evaluation pertaining to splenic injury are presented below.

History and physical examination — A history of trauma to the left upper quadrant, left rib cage, or left flank should increase the suspicion for splenic injury. However, a negative history does not reliably exclude splenic injury. A penetrating object can injure the spleen even if the entrance wound is not in proximity to the spleen.

The patient may complain of left upper abdominal, left chest wall, or left shoulder pain (ie, Kehr's sign). Kehr's sign is pain referred to the left shoulder that worsens with inspiration and is due to irritation of the phrenic nerve from blood adjacent to the left hemidiaphragm.

Abdominal tenderness and peritoneal signs are the most common findings indicative of intra-abdominal injury; however, these are not sensitive or specific for splenic injury. Physical findings associated with splenic injury include left upper quadrant or generalized abdominal tenderness, abdominal wall contusion or hematoma (eg, seat belt sign), as well as left lower chest wall tenderness, contusion, or instability due to rib fractures. However, an unremarkable physical examination does not exclude splenic injury [8].

In the setting of injury, many patients have altered mental status (eg, neurologic injury, intoxication) or are intubated and sedated and cannot relate their symptoms or medical history. Every attempt should be made to identify any preexisting medical conditions by contacting the patient's primary clinicians, family members, or other caregivers. The presence of significant medical comorbidities and medical conditions requiring antiplatelet or anticoagulant medications needs to be determined as these may impact management decisions. A social history should be obtained to determine the feasibility of nonoperative management of splenic injury, if warranted. (See 'Contraindications to nonoperative management' below.)

A history of herbal medicine use is also important as some (eg, ginkgo biloba, saw palmetto, fish oil) have anticoagulant activity. (See "Overview of herbal medicine and dietary supplements", section on 'Surgical patients' and "Overview of herbal medicine and dietary supplements", section on 'Herb-drug interactions' and "Fish oil: Physiologic effects and administration", section on 'Safety'.)

Associated injuries — With blunt abdominal trauma, lower rib fractures, pelvic fracture, and spinal cord injury may also be present [9]. Hollow viscous injuries are estimated to occur in 3 percent of patients with blunt splenic injury [10]. Although the presence of rib fractures increases the likelihood of splenic injury, there is no association between the number of ribs fractured and splenic injury severity [11].

The types of injuries associated with penetrating trauma depend upon the type of implement or missile used and its trajectory. Injuries to adjacent organs including the heart, esophagus, aorta, stomach, diaphragm, pancreas, bowel, or left kidney can occur in conjunction with splenic laceration. (See "Initial evaluation and management of abdominal gunshot wounds in adults" and "Initial evaluation and management of abdominal stab wounds in adults".)

Diagnostic evaluation — Evaluation of the abdominal trauma patient commonly uses focused assessment with sonography in trauma (FAST exam) and computed tomography (CT). The FAST exam is more useful in hemodynamically unstable patients; however, a negative FAST examination is not adequate to exclude splenic injury, particularly intraparenchymal injury. The use of diagnostic peritoneal aspiration/lavage (DPA/DPL) is less common, having been largely replaced by the FAST examination in most major trauma centers. The value of these tests in the initial evaluation of the patient with blunt or penetrating abdominal or thoracic trauma is discussed in detail elsewhere.

●(See "Initial evaluation and management of blunt abdominal trauma in adults" and "Initial evaluation and management of abdominal gunshot wounds in adults" and "Initial evaluation and management of abdominal stab wounds in adults".)

●(See "Initial evaluation and management of blunt thoracic trauma in adults" and "Initial evaluation and management of penetrating thoracic trauma in adults".)

Specific diagnostic findings of splenic injury are described in the sections below.

FAST findings — Signs of splenic injury observed with FAST examination include a finding of hypoechoic (ie, black) rim around the spleen, which may represent subcapsular fluid or intraperitoneal perisplenic fluid, or fluid in Morison's pouch (hepatorenal space).

CT findings — In noninjured patients, CT scan is typically performed with oral (PO) and intravenous (IV) contrast. However, most trauma centers no longer administer PO contrast, because scans performed without oral contrast, have sufficient detail to establish and grade splenic injury. For obvious reasons, CT scan without intravenous contrast has low sensitivity for parenchymal injury and cannot establish the presence of active bleeding (ie, contrast blush, active extravasation) [12]. However, the benefits of using IV contrast administration to diagnose bleeding need to be weighed against the risk of complications related to IV contrast (eg, contrast-induced nephropathy), particularly in older adults. Although a noncontrast CT scan may demonstrate splenic disruption, subcapsular hematoma, hemoperitoneum, or more specifically, hemorrhage in the left anterior pararenal space, a contrast-enhanced CT is required for to demonstrate parenchymal and vascular injuries. When IV contrast is used, the arterial phase of image acquisition improves detection of traumatic contained splenic vascular injuries and should be considered to optimize detection of traumatic splenic injuries with CT [13,14]. However, the arterial phase alone is suboptimal for the evaluation of parenchymal injuries because of the heterogenous enhancement of the spleen on the arterial phase. Therefore, the portal venous phase is essential to assess  parenchymal injuries.

The differentiation between ascites and blood is made using the Hounsfield unit scale, which is a transformation of the linear attenuation coefficient of a material relative to water (at standard temperature and pressure). The Hounsfield unit of water (eg, ascites) is zero, and that of IV contrast 130. The value for blood varies depending upon whether it is clotted, and if so, the age of the clot. (See "Principles of computed tomography of the chest", section on 'General description'.)

CT scan findings that indicate splenic injury include:

●Hematoma – High density on noncontrast and low density on contrast-enhanced CT .

•Perisplenic – Localized fluid collections around the spleen (especially those with an elevated Hounsfield unit measurement) are highly suggestive of splenic injury.

•Intraparenchymal – Hypodense regions represent areas of parenchymal disruption, intraparenchymal hematoma, or subcapsular hematoma.

•Subcapsular – Follows the splenic contour and compress parenchyma).

●Laceration – Low-density linear areas of parenchymal disruption in the spleen. These may be confused with splenic clefts or lobulations that have smooth margins and extend to the splenic surface.

●Active bleeding – Extravasation of contrast from the splenic artery and its branches. Active extravasation of contrast implies ongoing bleeding and the need for urgent intervention [15-17]. (See 'Management approach' below.)

●Parenchymal vascular injury – Contrast blush describes hyperdense areas within the splenic parenchyma that represent traumatic disruption or contained vascular injury such as a pseudoaneurysm or arteriovenous fistula.

●Hemoperitoneum – Briskly bleeding splenic lacerations may establish blood density fluid throughout the abdomen.

●Splenic infarction – Occasionally, splenic infarction due to vascular thrombosis may follow in the wake of a vascular injury or be an unanticipated finding in those who are hypercoagulable.

Other imaging — Plain films, organ-based ultrasound imaging, and magnetic resonance imaging (MRI) are of limited value in the acute diagnosis of splenic injury.

Plain films are generally nonspecific but may demonstrate rib fracture or medial displacement of the gastric air bubble (ie, Balance sign) raising suspicion for a splenic injury.

MRI and organ-based ultrasound examination may be time consuming to perform and may put the patient in a location of the hospital remote from ready access and intervention. However, MRI may be applicable in a subset of hemodynamically stable patients with indeterminate spleen lesions on CT scan [18], or in those who cannot undergo CT scan (eg, allergic to IV contrast) [19]. Noncontrast CT remains preferable for the acute diagnosis of splenic injury due to speed and accessibility.

SPLENIC INJURY GRADING — The American Association for the Surgery of Trauma (AAST) has published a spleen injury grading scale based upon the anatomic injury identified on computed tomography (CT) scan or intraoperatively (table 1) [20,21]. The grade of injury and the degree of hemoperitoneum on CT scan relate to the success of nonoperative management but do not consistently predict the need for initial operative intervention [22-26]. (See 'Management approach' below.)

The AAST imaging criteria for splenic injury are as follows [21]:

●Grade I – Subcapsular hematoma <10 percent surface area. Parenchymal laceration <1 cm in depth (picture 1). Capsular tear.

●Grade II – Subcapsular hematoma 10 to 50 percent surface area; intraparenchymal hematoma <5 cm. Parenchymal laceration 1 to 3 cm in depth.

●Grade III – Subcapsular hematoma >50 percent of surface area; ruptured subcapsular or intraparenchymal hematoma ≥5 cm. Parenchymal laceration >3 cm in depth.

●Grade IV – Any injury in the presence of a splenic vascular injury or active bleeding confined within splenic capsule. Parenchymal laceration involving segmental or hilar vessels producing >25 percent of devascularization (picture 2).

●Grade V – Any injury in the presence of splenic vascular injury with active bleeding extending beyond the spleen into the peritoneum. Shattered spleen.

The AAST grade identified in the operating room is not always concordant with the grade of injury identified on imaging due to technical issues and variability of CT scan interpretation [22,23]. A modified CT grading system has been proposed that may better identify those patients who would benefit from initial angiographic embolization [27].

MANAGEMENT APPROACH — Splenic injury can be initially managed with observation, angiographic embolization, or surgery depending upon the hemodynamic status of the patient, grade of splenic injury, and presence of other injuries and medical comorbidities (figure 1) [28,29]. The management approach used may vary from institution to institution depending upon the availability of resources [30,31].

●Hemodynamically unstable – Based upon Advanced Trauma Life Support (ATLS) principles, the hemodynamically unstable trauma patient with a positive focused assessment with sonography in trauma (FAST) scan or diagnostic peritoneal aspiration/lavage (DPA/DPL) requires emergency abdominal exploration to determine the source of intraperitoneal hemorrhage [32,33]. (See 'Trauma evaluation' above.)

●Hemodynamically stable – Hemodynamically stable patients with low-grade (I to III) blunt or penetrating [34] splenic injuries without any evidence for other intra-abdominal injuries, active contrast extravasation, or a blush on computed tomography (CT) may be initially observed safely (algorithm 1). In general, patients who meet the criteria for observation but who require intervention to manage extra-abdominal injuries (eg, leg fracture stabilization) can also be safely observed. (See 'Observation' below.)

CT scan findings of contrast extravasation or vascular blush have higher failure rates for observational management [16]. These patients may benefit from initial splenic embolization followed by continued observation to verify the success of the intervention. Another indication for embolization is intraparenchymal pseudoaneurysm formation. Splenic embolization is controversial for higher-grade (IV, V) injuries and in patients older than 55. (See 'Splenic embolization' below.)

Surgery is indicated in patients who cannot be adequately observed (due to limited resources or other injuries), are unlikely to tolerate a significant episode of hypotension, and those who fail nonsurgical management (ie, observation, embolization). (See 'Failure of nonoperative management' below and 'Operative management' below.)

Whether the management approach adopted for trauma patients can be extrapolated to guide the management of iatrogenic splenic trauma is unclear. Although splenic salvage is sometimes attempted for iatrogenic splenic trauma that occurs during surgery, more than 70 percent of patients ultimately undergo splenectomy [35]. It is unclear whether this is truly necessary or due to surgeons' "discomfort" at watching a slowly oozing low-grade injury that would then necessitate a second surgery if nonoperative management fails.

NONOPERATIVE MANAGEMENT — Splenic trauma was nearly uniformly managed with surgical exploration and splenectomy or attempted splenic salvage prior to the introduction of nonoperative management algorithms in the pediatric population. What seemed initially to be a radical approach was adopted over time by the adult trauma community. Nonoperative management, encompassing both observation and embolization techniques, is used to manage 50 to 70 percent of cases, typically for patients with lower-grade injuries [36-39]. (See 'Splenic injury grading' above.)

The rationale for nonoperative management is based upon the assumption that salvaging functional splenic tissue avoids the surgical and anesthetic risks and complications associated with laparotomy and abrogates the risk of early infectious complications and postsplenectomy sepsis [28,40].

However, immune competence after injury that does not require removal of the spleen (eg, embolization, partial splenectomy) depends on the immunologic functionality of the residual splenic tissue and does not appear to be grade specific. The small risk of postsplenectomy sepsis appears higher at the extremes of age but may be influenced by concomitant immune deficiency from solid organ transplantation, malignancy, and HIV disease. (See 'Immunocompetence after splenic injury' below.)

Contraindications to nonoperative management — Nonoperative management is not appropriate for hemodynamically unstable patients, patients with generalized peritonitis, or patients with other intra-abdominal injuries requiring surgical exploration [28].

Portal hypertension is a relative contraindication due to the increased venous pressures that may prevent clot formation and control of hemorrhage even after successful splenic embolization. In a review of the National Trauma Data Bank, patients with liver cirrhosis had higher rates of complications, failure of nonoperative management, and mortality compared with noncirrhotic patients [41]. In a separate case control study, cirrhosis was an independent risk factor for splenectomy following splenic injury [42]. However, after propensity score matching, mortality after splenic injury was associated only with the admission MELD (Model for End-stage Liver Disease) score and not the splenectomy procedure. (See "Model for End-stage Liver Disease (MELD)".)

Other relative contraindications include higher-grade splenic injury (>grade III) [43,44], active contrast extravasation, large-volume hemoperitoneum (though difficult to accurately quantify), traumatic brain injury [43,45], refusal of blood transfusion in the setting of preexisting anemia, or altered neurologic status precluding adequate serial abdominal examination.

There is a higher failure rate of nonoperative management with increasing grade of injury, though all grades of splenic trauma can bleed and often in an unpredictable fashion [44,46,47]. The optimal management of hemodynamically stable patients with higher-grade (IV, V) injuries remains controversial, though grade V injuries are generally unsuitable for embolization due to vascular disruption. We prefer to initially manage hemodynamically stable patients with grade III or IV splenic injury with angiographic embolization as part of their nonoperative management, provided they do not have other injuries that require abdominal exploration or medical comorbidities providing a contraindication.

●In a small retrospective review, 60 percent of patients with higher-grade injuries were taken directly to the operating room. The remaining patients were managed nonoperatively with 55 percent of these patients ultimately requiring surgery [48].

●The Splenic Arterial Embolization to Avoid Splenectomy (SPLASH) trial randomly assigned hemodynamically stable patients with grade III, IV, or V injury to prophylactic embolization (55 patients) versus observation (60 patients) [49]. Twenty-one patients (32.3 percent) in the surveillance group ultimately required an intervention (19 embolization and 3 splenectomies). Seventy-one percent of patients with grade IV or higher required either embolization or splenectomy. There was high percentage of splenic salvage in both groups (98.2 percent prophylactic group and 93.3 percent surveillance.)

Embolization is also relatively contraindicated in patients older than 55 due to higher failure rates in these patients. The splenic capsule thins with age (age >55 years) and may render nonoperative management of higher-grade injuries (>grade III) in these patients less successful. However, injury severity-adjusted mortality rates do not appear significantly higher in this population compared with younger patients, but, overall, the experience with nonoperative management of higher-grade splenic injury in older patients is limited. Retrospective reviews suggest, however, that carefully selected individuals over 55 who are hemodynamically stable, and have no significant medical comorbidities, can also be safely managed with observation, with or without embolization [37,50,51]. The largest of these studies examined 1008 patients ≥55 years of age who sustained blunt splenic injury [37]. Of the patients who did not require immediate surgical intervention, 75 percent were successfully managed nonoperatively. Among three age groups, 55 to 64, 65 to 74, and >75 years of age, failure rates for nonoperative management increased and were 19, 27, and 28 percent, respectively, but these differences were not significant, possibly due to the small number of patients in each group. In a 2011 review of the National Trauma Data Bank, increasing age was associated with a slightly increased risk for failure of nonoperative management (odds ratio 1.014 per year of age) [52].

Observation — Successful observation during nonoperative management for splenic trauma depends upon proper patient selection and the availability of adequate resources within the institution [28,53,54]. Clinical grading based on computed tomography (CT) combined with the abdominal abbreviated injury score (AIS) were identified as the best predictor of successful observation [55]. Patients must be closely monitored by nursing and medical staff, and sufficient flexibility should be available to allow urgent/emergency intervention should arteriography or surgery be required. (See 'Failure of nonoperative management' below.)

General care — Wide variation exists in the clinical application of nonoperative strategies, but, in general, patients are admitted to a monitored care setting, either an intensive care or step-down unit, depending upon the capabilities of the unit, grade of splenic injury, nature and severity of other injuries, and clinical status [56,57]. We initially place the patient on bed rest, though no clear benefit exists for this practice. In a small retrospective study, early mobilization of patients with nonoperative spleen injuries appeared to be safe [58]. In agreement with an expert panel, we obtain serial hemoglobin levels every six hours in the first 24 hours [59]. Patients are not given a diet (ie, nil per os [NPO]) for at least the first 24 hours. When the hemoglobin level is stable and operative intervention unlikely, the patient may eat.

Small retrospective studies have suggested that early thromboprophylaxis (within 48 hours) may be safe, but there are currently no standards for the initiation of prophylaxis in patients who are managed nonoperatively [60-62]. Venous thromboembolism prophylaxis may be contraindicated by other associated injuries.

Follow-up imaging — There is debate in the literature and among clinicians regarding the utility of follow-up imaging. In a consensus study using the Delphi method, only 46 percent of the experts surveyed recommended routine inpatient follow-up imaging [59]. In one retrospective review that included 773 patients with blunt splenic injury, outcomes of a cohort of patients (n = 616 patients from 2000 to 2012) who had mandatory repeat CT evaluation at 48 hours and angioembolization (if indicated) were compared with an earlier cohort for whom repeat scanning was selective (n = 157 from 1995 to 1999) [63]. The proportion of patients managed nonoperatively (77 versus 53) and overall rate of splenic salvage (77 versus 46 percent) were significantly higher in the later cohort of patients.

We perform a follow-up study in patients whose clinical situation indicates the need (eg, falling hemoglobin, increasing abdominal pain, left shoulder pain, fever). In some patients with higher-grade injuries (III to V), a repeat scan within 24 to 48 hours may be needed if the clinical situation is unclear, such as in the setting of evolving neurologic injury when the physical examination may be sequentially less reliable than upon admission.

Duration — The duration of observation should be individualized based upon the grade of splenic injury, nature and severity of other injuries, and the patient's clinical status. In a survey of actively practicing trauma surgeons, there was agreement that higher-grade injury generally required longer observation periods [56]. Another expert group observed patients for one to three days [59]. A common but not evidence-based practice regarding the duration of observation following splenic injury is that the number of days of observation is equal to the injury grade plus one [64].

An observation period of five days identifies at least 95 percent of patients who would require some form of intervention [65,66]. One multicenter trial found that 86 percent of patients who failed nonoperative management did so within 96 hours of hospital admission, with 61 percent of failures occurring during the first 24 hours [46]. Patients with higher-grade injuries may require more prolonged periods of observation. (See 'Failure of observation' below.)

Failure of observation — Patients who fail observation require either splenic embolization, or more commonly, operative management. Patients may fail observational management either as an inpatient or, more rarely, as an outpatient presenting with "delayed splenic rupture." A prospective study of 383 patients from 11 trauma centers ascertained the long-term risk of splenectomy after an initial 24 hours of nonoperative management [67]. Twelve patients (3.1 percent) underwent in-hospital splenectomy between 24 hours and nine days after injury. Only one patient, among 366 patients discharged with a spleen, ruptured on postinjury day 12. It is likely that "delayed rupture" more accurately describes those patients with splenic parenchymal pseudoaneurysms, the walls of which degrade during the normal process of clot dissolution with bleeding in a delayed fashion. In one review, delayed pseudoaneurysm or arterial extravasation was detected in 6 percent of patients and distributed among all injury grades [63].

Indications to pursue intervention include hemodynamic instability, the development of diffuse peritoneal signs, or decreasing hemoglobin attributed to splenic hemorrhage. Hypotension may be absolute or relative, or evidenced as persistent tachycardia in spite of adequate fluid resuscitation. The clinical manifestations of hypovolemia due to blood loss are discussed in detail separately.

When observing the patient with splenic injury, there is no consensus with respect to level of hemoglobin, change in hemoglobin, or transfusion volume that prompts a need for intervention. Some surgeons intervene prior to the need for any transfusion as a means of avoiding allogeneic exposure, while others make provisions for one to two units of packed red blood cells (PRBCs) prior to further intervention.

The choice to pursue embolization or surgery in many institutions is governed by the availability of the appropriate resources and the patient's ability to tolerate the time needed to set up the interventional radiology suite (or operating room with dedicated arteriography), get personnel in place, and perform the embolization procedure, which, depending upon the patient's anatomy, can be lengthy. (See 'Splenic embolization' below and 'Operative management' below.)

Splenic embolization — Angiographic embolization was first applied to the management of splenic injury in 1981. Splenic embolization requires specialized imaging facilities and a vascular interventionalist (ie, interventional radiology, vascular surgeon) experienced with celiac artery catheterization and embolization techniques. Success rates for embolization vary depending upon institution, embolization technique, arterial accessibility, operator skill, and the type of embolization material. Where available, embolization is potentially most useful when employed selectively in hemodynamically stable patients who have CT findings that include active contrast extravasation, splenic pseudoaneurysm, or large-volume hemoperitoneum [16,24,25,68-71].

A number of observational studies have demonstrated that nonoperative management is more successful with the adjunctive use of angioembolization [15,72-79].

●In a cohort analysis, 222 patients with blunt splenic injury treated between 1991 and 1998 were compared with 408 patients treated between 1998 and 2005 [76]. The frequency of nonoperative management (61 versus 85 percent, respectively), injury severity scale (21 versus 27, respectively), frequency of splenic artery embolization (3 versus 23 percent, respectively), and success of nonoperative management (77 versus 96 percent, respectively) all increased significantly between the earlier and later cohort. Hospital mortality rates (12 versus 6 percent) and mean hospital length (15 versus 9 days) decreased significantly.

●A retrospective multicenter trial that included 1275 patients found that angioembolization significantly increased the likelihood of splenic salvage (odds ratio [OR] 5, 95% CI 1.8-13.5) [73].

●In a small study of 39 patients, splenic artery embolization increased the success rate for nonsurgical management from 74 to 89 percent [75].

Retrospective reviews have found variable success rates (57 to 95 percent) for splenic salvage that include embolization in patients with higher-grade (III, IV, V) splenic injuries [15,39,68,70,78,80-84]. However, in a study where the trauma protocol was adapted to require arteriography and possible embolization for all patients with grade III to V injuries, the failure rate of nonoperative management decreased from 15 to 5 percent [78].

The technique of splenic embolization involves first gaining percutaneous access to the abdominal aorta via the brachial or femoral artery. The celiac axis is cannulated and a celiac arteriogram is performed to confirm the CT findings and evaluate the splenic vasculature. The presence of contrast extravasation from the splenic parenchyma supplied by the short gastric vessels on celiac arteriogram should prompt operative intervention as these injuries are less amenable to embolization due to the technical difficulties in accessing the short gastric vessels.

Embolization of the splenic artery proximally or distally can be performed [39]. Nonrandomized studies have not demonstrated the superiority of one technique over the other, though failure rates for nonoperative management may be greater when proximal embolization is applied to patients with higher-grade injuries [85]. However, complication rates related to splenic embolization may be higher with distal embolization [86].

Depending upon the nature of the injury and technical factors, embolization coils, microspheres, absorbable gelatin sponge, endogenous clot, or a vascular plug device can be used to interrupt blood flow in major or branch vessels of the spleen effecting total or partial splenic embolization [39,87]. Splenic artery embolization may not completely interrupt blood flow from short gastric vessels due to their collateral flow from the left gastric and gastroepiploic arteries. Ongoing bleeding from these vessels may not be obvious with selective splenic artery angiogram, and thus, selective celiac arteriography should be performed.

Benefits and risks of nonoperative management — Because there is no operation, surgical risks and potential complications are eliminated with successful nonoperative management. An additional benefit of successful nonoperative management is the preservation of functional splenic tissue. Disadvantages of nonoperative management include an increased risk of missed injury, particularly hollow viscus injury, a risk of delayed bleeding, transfusion-related illness, and, when used, the additional risks associated with embolization techniques.

Patients with missed hollow viscus injury present with worsened abdominal pain and the development of peritoneal signs, generally by postinjury day 4. These patients require operative intervention and should undergo concomitant definitive management of their splenic injury, if indicated. (See "Traumatic gastrointestinal injury in the adult patient".)

Blood transfusion is associated with complications that can include intravascular volume overload (transfusion-associated circulatory overload [TACO]), transfusion-related acute lung injury (TRALI), hypothermia, coagulopathy, immunologic and allergic reactions, as well as immunomodulation (transfusion-related immune modulation [TRIM]). Some clinicians feel that transfusion-related risks do not justify nonoperative management strategies for which the volume of transfusion may be increased. The risks associated with blood transfusion are discussed in detail elsewhere. (See "Use of blood products in the critically ill", section on 'Complications' and "Transfusion-related acute lung injury (TRALI)" and "Transfusion-associated circulatory overload (TACO)".)

Splenic embolization is associated with additional risks that include bleeding, pseudoaneurysm formation at the arterial puncture site, splenic infarction, splenic/subdiaphragmatic abscess, inadvertent embolization of other organs (eg, kidneys) or lower extremities, allergic reaction to contrast, and contrast-induced nephropathy [86]. The risk of contrast-induced nephropathy may be greater when embolization is performed following contrast CT scan, especially in patients who may already be volume depleted. Contrast-induced nephropathy and its prevention are discussed in detail elsewhere. (See "Contrast-associated and contrast-induced acute kidney injury: Clinical features, diagnosis, and management" and "Prevention of contrast-associated acute kidney injury related to angiography".)

Failure of nonoperative management — Failure of nonoperative management (observation and/or embolization) is defined as the need for operative intervention and is generally associated with ongoing bleeding as indicated by the need for ongoing volume expansion or transfusion, or hemodynamic instability. Hypotension may be absolute or relative, or evidenced as persistent tachycardia despite adequate fluid resuscitation. The clinical manifestations of hypovolemia due to blood loss are discussed in detail separately.

Failure rates for observational management range from 6 to 20 percent and depend upon age, injury severity score, grade of splenic injury, frequency with which embolization techniques are employed, and, most importantly, the appropriateness of patient selection for nonoperative management [38,46,47,88,89]. In retrospective studies, up to 40 percent of patients failing nonoperative management were found to have inappropriate indications for a nonoperative approach [38,90,91].

Rebleeding and/or secondary splenic "rupture" following "successful" nonoperative management is a rare but potentially disastrous complication that cannot be reliably predicted. More than 90 percent of secondary splenic "ruptures" occur within 10 days following the initial trauma; most of the remainder occur within two weeks [46,92].

The need for subsequent splenectomy following conservative management is overall low. In a review of the United States Healthcare Cost and Utilization Project's Nationwide Readmission Database, adult patients with isolated splenic injury were studied [93]. The overall readmission rates at six months was 21.1 percent, which did not differ significantly based on initial management strategy (ie, angioembolization, splenectomy, no procedure). The rate of delayed splenectomy was 4.5 percent among readmitted patients, and overall, the chance of readmission for splenectomy after initial nonoperative management was 1.2 percent.

Follow-up care

Resumption of normal activities — Upon discharge, patients are typically restricted from participation in high-risk activities such as skiing, mountain biking, skydiving, wrestling, contact sports, military combat, and vigorous sexual intercourse for a period of up to three months. While there are no clinical studies to support this duration, one assumes that repeat trauma to the fragile, healing spleen could lead to reinjury [56]. In one retrospective review, healing was demonstrated radiographically within two months of injury in 80 percent of patients; however, grade V injuries were excluded in this study [94].

Imaging studies — With successful nonoperative management of splenic injury, we do not routinely perform repeat CT imaging. The Eastern Association for the Surgery of Trauma (EAST) guidelines concluded that there are insufficient data to determine whether routine follow-up imaging is necessary [30]. In one survey of EAST members, 85 percent of respondents did not routinely reimage [56]. The World Society of Emergency Surgery Consensus has suggested reimaging grade III and higher injuries at 48 to 72 hours after injury [95]. The delayed presentation of splenic pseudoaneurysms have been reported and may support a decision to reimage [63,68,96]. In a study of 104 patients, delayed formation of splenic pseudoaneurysms occurred in 15.4 percent of patients and was detected one to eight days after admission [97]. Approximately one half of the pseudoaneurysms spontaneously thrombosed without the need for specific intervention.

Repeat CT scan or contrast-enhanced ultrasound (provided that the injury can be adequately visualized) can be considered in select patients [98]. Reimaging may be indicated to lift an activity restriction, or for patients whose work requirements or lifestyles place them at higher risk for reinjury if healing is not complete [99]. Examples include professional athletes, military service personnel, and extreme sports enthusiasts. Reimaging may also be appropriate for those who are planning to travel to regions of the world with limited health care access to document complete healing prior to travel. For these patients, reimaging is typically performed at three months following the injury.

OPERATIVE MANAGEMENT — Patients sustaining abdominal trauma who are hemodynamically unstable, those who are not candidates for nonoperative management, and those who fail nonoperative management strategies require surgical exploration and either splenic salvage or splenectomy. The choice of procedure depends upon the nature and severity of splenic injury, clinical status of the patient, and associated injuries. Surgical management of traumatic splenic injury is discussed separately. (See "Surgical management of splenic injury in the adult trauma patient".)

IMMUNOCOMPETENCE AFTER SPLENIC INJURY — Immunization is recommended for asplenic patients since splenectomy impairs opsonization of encapsulated organisms [100,101]. Information on specific vaccines and vaccine schedules are discussed elsewhere. (See "Prevention of infection in patients with impaired splenic function", section on 'Vaccinations'.)

Ideally, vaccines are administered either 14 days prior to or 14 days following splenectomy for maximal immunologic benefit [102,103]. Delaying vaccinations for 14 days postoperatively increases the antibody response but may not be feasible in all trauma patients given the historically sporadic follow-up in this patient population. Many centers will therefore vaccinate the patient at the time of discharge, regardless of the postoperative day. Asplenic patients should also receive yearly influenza vaccinations.

We recommend that asplenic patients wear medical jewelry and carry medical information cards identifying them as asplenic to alert future health care providers under the circumstance that the patient is unable to do so.

The need for immunization of patients following treatment for splenic injury compared with those undergoing elective splenectomy is still being defined. We vaccinate all patients who have undergone splenectomy following traumatic rupture because the extent to which a patient may (or may not) have functional residual splenic tissue (ie, splenosis) is uncertain. An experimental study demonstrated the ability of autogenic splenic implants to increase the rate of bacterial clearance and to remove colloidal substance and altered erythrocyte corpuscular inclusions, such as Howell-Jolly, Heinz, and Pappenheimer bodies, from the bloodstream [104]. However, whether this occurs with traumatic splenosis is unknown. Patients with deliberate replantation or spontaneous splenosis (image 1) have pitted red cell counts (counts less than 15 percent are consistent with immunocompetence) that are lower than those seen in splenectomized patients who do not have splenosis, but the count is not necessarily normal [105]. (See "Splenomegaly and other splenic disorders in adults", section on 'Splenosis'.)

Following splenic salvage surgery, splenic embolization, or nonoperative management, we agree with general consensus and available guidelines that immunization is not necessary [106-109], though some clinicians may disagree. Available in vitro studies indicate immunocompetence in these patients [109-119]. In clinical studies of patients undergoing partial splenectomy for reasons other than trauma, humoral immunity was depressed only transiently following partial splenectomy, and compared with total splenectomy, partial splenectomy was associated with less risk for postsplenectomy infection [120,121]. In a systematic review of 12 observational studies, most found that splenic function was preserved after partial splenectomy or splenic embolization [122]. The validity of the studies that did not was questioned as splenic function was assessed only after the first week following embolization. However, uncertainty remains since these studies used a variety of clinical parameters to assess the immunologic and hemofiltration function of the spleen, and the best parameter/test to assess immunocompetence in this population has not been determined. As an example, one controlled trial evaluating red blood cell pit counts found no differences for patients following successful nonoperatively managed high-grade injury (0.6 percent) and controls (0.7 percent); counts following splenectomy were 20.7 percent [123].

SOCIETY GUIDELINE LINKS — Links to society and government-sponsored guidelines from selected countries and regions around the world are provided separately. (See "Society guideline links: Traumatic abdominal and non-genitourinary retroperitoneal injury".)

SUMMARY AND RECOMMENDATIONS

●Mechanisms of splenic injury – Splenic injury can result from either blunt or penetrating chest or abdominal trauma; blunt mechanisms are more common. Splenic injury can also be due to iatrogenic injury during the course of another procedure involving the colon, stomach, pancreas, kidney, or with exposure and reconstruction of the proximal abdominal aorta; the risk is greatest for patients undergoing colon resection. (See 'Mechanism of injury' above.)

●Clinical features – A suspicion for splenic injury is increased with left upper quadrant and/or left chest trauma; however, clinical history and physical examination are not sufficiently sensitive or specific for the presence of splenic injury. Initial trauma evaluation is based upon protocols from the Advanced Trauma Life Support (ATLS) program developed by the American College of Surgeons Committee on Trauma. (See 'Trauma evaluation' above and 'Diagnostic evaluation' above.)

•Findings indicative of splenic injury on focused assessment with sonography for trauma (FAST) examination include perisplenic or free intraperitoneal fluid.

•CT scan findings consistent with splenic injury include splenic hypodensity, intraparenchymal or subcapsular hematoma, intravenous contrast blush, active intravenous contrast extravasation, or hemoperitoneum.

●Splenic injury grading – Splenic injury is graded (I through V) depending upon the extent and depth of splenic hematoma and/or laceration identified on CT scan or intraoperatively. Splenic injury grading is one factor used to stratify patient management. Other factors include associated injuries and medical comorbidities. (See 'Splenic injury grading' above.)

●Management of hemodynamically unstable patients – Per ATLS protocol, hemodynamically unstable patients with a positive FAST exam or diagnostic peritoneal lavage or aspirate (DPL/DPA) require operative surgical exploration to determine the source of life-threatening hemorrhage that may be due to splenic injury. (See 'Management approach' above.)

●Management of hemodynamically stable patients – For hemodynamically stable patients with low-grade (I to III) injuries, we suggest nonoperative management over definitive surgical intervention (Grade 2C). Observation involves monitored care, serial abdominal examination, and serial hemoglobin assessment and may involve splenic angioembolization depending upon resources. Failure of nonoperative management indicates a need for angiographic embolization, if not initially used, or surgical exploration. (See 'Observation' above.)

•For hemodynamically stable patients with active contrast extravasation or contrast blush on CT scan, we suggest initial splenic embolization over observation (Grade 2C). Splenic embolization requires specialized imaging facilities and a suitably experienced interventionalist. Failure of embolization indicates the need for surgery. (See 'Splenic embolization' above.)

•For initially hemodynamically stable patients who develop hemodynamic instability during the course of nonoperative management, we suggest surgical exploration over splenic embolization (Grade 2C). (See 'Failure of nonoperative management' above.)

●Vaccination – Asplenic patients (ie, postsplenectomy) have impaired immunity to encapsulated organisms and should be immunized against encapsulated organisms. For patients who have not undergone splenectomy, either because of successful nonoperative management (ie, observation with or without angioembolization) or operative splenic salvage, we suggest no immunization (Grade 2C). (See 'Immunocompetence after splenic injury' above.)