Although protected under the bony ribcage, the spleen remains the most commonly affected organ in blunt injury to the abdomen in all age groups. While some references occasionally document liver injuries as being more common, blunt injuries to the spleen are documented more frequently as the primary solid organ injury in the abdomen. These injuries are common in both rural and urban environments and result from motor vehicle crashes, domestic violence, sporting events, and accidents involving bicycle handlebars. See the images below.
View Image | Intra-parenchymal blush observed on helical CT scan. |
View Image | Grade 4-5 splenic laceration on helical CT scan. |
A general surgeon in a community hospital is just as likely to observe and treat a splenic injury as the full-time trauma surgeon in an American College of Surgeons (ACS) –verified Level 1 or Level 2 trauma center. For this reason, all physicians involved in emergency care, especially surgeons, whether rural or urban, must keep up-to-date on issues regarding splenic injury diagnosis, splenic salvage techniques, indications for nonoperative treatment, and potential complications arising from both operative splenectomy and nonoperative management of this important organ.
In 1893, Reigner published the first documented successful splenectomy in the German literature. Operative mortality rates remained high until the 1950s, when new and rapid advancements in surgical and anesthesia sciences occurred. Nonoperative care during this period was predominantly fatal. Prior to the advent of CT scanning, physical examination and diagnostic procedures such as diagnostic peritoneal lavage (DPL) and radioisotope scans were the only diagnostic methods. Minor splenic injury was probably frequently missed, while major injury prompting laparotomy for hypotension or physical findings was the norm.
With the widespread availability of computed tomography surgeons began to focus on those needing surgery and those who could be observed safely. Starting with the pediatric population and expanding into the adult population, nonoperative observation became more prevalent for hemodynamically stable patients. Further improvements in CT sensitivity and specificity made vascular extravasation easier to diagnose, and interventional radiology became an integral part of the management of splenic injuries, in some institutions replacing emergency operation as the treatment of choice. Some authors have even noted that resident experience with splenectomy for trauma have been surpassed by medical indications for splenectomy and that emergent splenectomy may be an endangered species in training centers.[1]
The spleen, weighing 75-150 g, is a highly vascular organ that filters an estimated 10-15% of total blood volume every minute. The spleen may hold 40-50 mL of red cells in reserve on average; however, with changes in internal smooth muscle, it can pool significantly more blood. Historically, many early shock studies performed in canine models were invalidated when it was discovered that dogs could autotransfuse stored red cells from their spleen with smooth muscle contraction. Humans do not have this ability. As much as 25% of the circulating platelets are estimated to be held in reserve in the spleen. Although protected anatomically under the rib cage in the left upper quadrant of the abdomen, it is frequently injured by blunt external trauma. It can also be iatrogenically injured in emergency operations, especially when preexisting adhesions make mobilization of intra-abdominal structures difficult.
Because of the immunologic function of the spleen, interest over the last century has turned to salvage of the spleen rather than splenectomy. The advent of CT scanning has made conservative management more practical and safer for victims of splenic injury. CT scanning has facilitated safe, nonoperative management in young and old patients to an unprecedented degree, but deaths due to splenic rupture are still reported in hospital discharge statistics from both Level 1 trauma centers and community hospitals.
A thorough knowledge of splenic function, anatomy, and pathophysiology is necessary to continue the progress of the last decade and to decrease the mortality rate from this common injury in the United States and worldwide.
Determining the actual frequency of splenic injuries with precision in the United States or worldwide is not possible. Hospital discharge data may not document the injury if there are numerous, more serious injuries or diseases. A general consensus of trauma admissions at Level 1 trauma centers across the country suggests splenic injury occurs in as many as 25% of the average 800-1200 admissions for blunt trauma per year. This is a select population of patients with multiple injuries and does not take into account isolated splenic injuries observed and treated at nontrauma centers.
Splenic injury is most often observed in blunt trauma. While penetrating trauma (eg, gun shot wounds, knife wounds) may involve the spleen, the incidence of injury is well below that of the small and large intestine. A third mechanism that combines aspects of blunt and penetrating trauma occurs with explosive type injuries, as seen in warfare and civilian bombing.
Although the spleen is relatively protected under the ribcage, injury due to rapid deceleration, such as occurs in motor vehicle crashes, direct blows to the abdomen in domestic violence, or leisure and play activities such as bicycling, frequently result in a variety of splenic injuries.
Another cause of splenic injury has been gaining notice. There have been case reports of splenic injury following colonoscopy.[2] Ha and Minchin performed a literature search to identify the demographic profile, risk factors, clinical presentations, diagnosis and management of this rare complication.[3] The investigators found 66 patients (median age, 65y) with a 4.5% mortality rate, the majority (n = 41, 62.1%) of which occurred in uneventful colonoscopies. Symptoms primarily (74%) appeared within 24 hours, and workup in the form of blood tests and CT scanning was performed in the majority (93.9%).[3]
In addition, over half of (56.1%) affected patients underwent laparotomy and splenectomy, with the most common finds of splenic hematoma (47%), laceration (47%), and rupture (33.3%).[3] Ha and Minchin concluded that recognition of postcolonoscopy splenic injury as an important complication will not only rise, but it will be necessary given the increasing numbers of colonoscopies being performed for colorectal diseases and the possibility of delayed diagnosis resulting in adverse outcomes.
Though normally protected by its anatomic position, preexisting illness or disease can markedly increase the risks and severity of splenic injury. Infectious mononucleosis, malaria, and hematologic abnormalities can lead to acute or chronic enlargement of the spleen. This is often accompanied by a thinning of the capsule, making the spleen more fragile as well as engendering a greater mass effect in decelerating trauma. Minor impact in patients with splenomegaly reportedly results in major injury and the need for splenectomy.
The clinical presentation of splenic injury is highly variable. Most patients with minor focal injury to the spleen complain of left upper quadrant abdominal tenderness. Left shoulder tenderness may also be present as a result of subdiaphragmatic nerve root irritation with referred pain.
With free intraperitoneal blood, diffuse abdominal pain, peritoneal irritation, and rebound tenderness are more likely. If the intra-abdominal bleeding exceeds 5-10% of blood volume, clinical signs of early shock may manifest. Signs include tachycardia, tachypnea, restlessness, and anxiety. Patients may have a mild pallor noted only by friends and family. Clinical signs include decreased capillary refill and decreased pulse pressure. With increasing blood loss into the abdominal cavity, abdominal distension, peritoneal signs, and overt shock may be observed.
Hypotension in a patient with a suspected splenic injury, especially if young and previously healthy, is a grave sign and a surgical emergency. This should prompt immediate evaluation and intervention either in the OR or interventional radiology if a state of compensated shock can be maintained. Unstable patients have nearly exsanguinated in CT scanners while in the process of documenting splenic injury, when they would have been better served by exploration in the operating room or embolization in the IR suite.
In simple terms, unstable patients suspected of splenic injury and intra-abdominal hemorrhage should undergo exploratory laparotomy and splenic repair or removal. A blunt trauma patient with evidence of hemodynamic instability unresponsive to fluid challenge with no other signs of external hemorrhage should be considered to have a life-threatening solid organ (splenic) injury until proven otherwise. Transient responders, those patients who respond to an initial fluid bolus only to deteriorate again with a drop in blood pressure and increasing tachycardia, are also likely to have solid organ injury with ongoing hemorrhage. Patients with compensated shock may be managed by angioembolization but only if these services can be performed in a timely manner equivalent to that of operative intervention.
DPL may be a valuable adjunct if time permits and multiple other injuries are present. Focused abdominal sonographic technique (FAST) in experienced hands is helpful in documenting the presence or absence of blood in the peritoneal cavity, which highly suggests the possibility of splenic injury. However, bedside FAST in the resuscitation suite does not show actual splenic injury well enough to use as a diagnostic modality for solid organ injury imaging. Rozycki et al performed a pilot study using bedside organ assessment with sonography after trauma (BOAST) and documented its limitations in identifying solid organ injury, especially at lower grades of injury. FAST is excellent for documenting the presence or absence of intra-abdominal fluid but should not be viewed as an equivalent to CT scanning with regard to injury site determination.[4]
Sirlin et al showed that patterns of fluid accumulation on FAST may be used to improve identification of specific organ injuries, but this still does not approach the sensitivity and specificity of CT.[5]
In the stable trauma patient, commonly defined as a patient with systolic blood pressure greater than 90 mm Hg with a heart rate less than 120 beats per minute (bpm), CT scanning provides the most ideal noninvasive means for evaluating the spleen. Helical or spiral scanners may provide even more information and may clarify the degree of injury. In the cases of CT scan–documented splenic injury, the decision for operative intervention is determined by the grade of the injury, the patient's current and preexisting medical conditions, and the facilities available at the hospital, including the intensive care unit and the availability of operating and anesthesia services.
The availability of interventional angiographic services also impacts a surgeon's decision for or against operative intervention. The use of MRI has also been reported in the literature as an option in the patient with an elevated creatinine level.[6]
The major determining factors in operative intervention in the stable patient with a splenic injury include grade of injury (American Association for the Surgery of Trauma [AAST] scale), presence of intraperitoneal blood, presence of a blush on CT scan, calculated risk of rebleeding, presence and severity of concomitant injuries, and options regarding blood transfusion.
Signs of persistent bleeding and hemodynamic instability unresponsive to fluid and blood administration are clear indications for surgery. The decision for operative intervention in other cases requires the thoughtful consideration of the surgeon. Angioembolization, once contraindicated in compensated shock, has now been reported as a safe method of splenic salvage when immediately available in the treating facility.[7] A healthy 25-year-old patient who has a CT scan grade 4 laceration with stable vital signs and minimal fluid requirements may be safe to observe under controlled conditions, while a 55-year-old patient who is a Jehovah's Witness and who has a CT scan grade 2 oozing splenic injury and pelvic fracture would probably benefit more from early surgical intervention.
The spleen sits in the left upper quadrant of the abdomen under the diaphragm and lateral to the stomach. Left shoulder pain, also known as the Kehr sign, results when blood from an injured spleen irritates the diaphragm and creates referred pain. The spleen is completely encircled and covered with peritoneum except for the insertion of the splenic artery and vein. This capsule around the spleen, especially the thicker layer in young patients, provides added protection against blunt injury. The spleen is primarily fixated to the posterior aspect of the left upper quadrant by gastrosplenic and splenorenal ligaments. The size and thickness of these ligaments vary greatly, with some spleens appearing to be very mobile, while others appear fixed in the left upper quadrant.
The major arterial supply to the spleen is through the splenic artery, which branches off the celiac artery and runs superior and posterior to the pancreas. The artery commonly bifurcates externally to the spleen, supplying upper and lower poles separately, a finding that may make splenorrhaphy much easier for the operating surgeon. The splenic vein courses with the artery but empties into the superior mesenteric vein and then into the portal vein. The arterial supply and venous drainage of the spleen is augmented by the short gastric vessels that branch from the left gastroepiploic artery. These vessels may be as short as 1 mm, thus creating a challenge during emergency operative intervention. Notably, the splenic artery and vein may have small branches feeding the body and tail of the pancreas, so care should be taken in dissecting these vessels away from the splenic hilum.
The tail of the pancreas is often intimately positioned near the splenic hilum and can be easily damaged during splenectomy if adequate care is not taken to identify and protect the organ.
No contraindications to operative intervention exist in a hemodynamically unstable patient with a splenic injury. However, hypotension or unstable vital signs are a contraindication to CT scanning, and deaths due to splenic rupture and ongoing bleeding have occurred in the radiology suite while trying to document a splenic injury. Unstable patients can be assessed by FAST or DPL in addition to clinical examination but should not undergo CT scanning of the abdomen for diagnosis.
See the list below:
See the list below:
View Image | Intra-parenchymal blush observed on helical CT scan. |
See the list below:
See the list below:
Histologic findings may help to explain why a minor trauma resulted in a major splenic injury. Splenic rupture may follow after a seemingly minor transfer of kinetic energy because of organ expansion with capsular thinning or an abnormal internal architecture with reduced elasticity to the parenchyma. Such events may happen with splenomegaly due to hematologic abnormalities (eg, hereditary spherocytosis), infectious diseases (eg, malaria), and liver disease (eg, portal and splenic hypertension).
Splenic injury is graded using the standards published by the Organ Injury Scaling Committee of the AAST. Categories range from grade I (minor) to grade V (major) and correlate to the need for laparotomy. These grades are used in conjunction with nonoperative assessment (eg, CT scanning, angiography), operative intervention by laparotomy, or postmortem by autopsy. Some studies comparing CT staging with operative staging indicate that CT scanning overestimates the injury by as much as 10%. However, CT scan findings correlate well with the need for operative intervention.
The trend in management of splenic injury continues to favor nonoperative or conservative management. This varies from institution to institution but usually includes patients with stable hemodynamic signs, stable hemoglobin levels over 12-48 hours, minimal transfusion requirements (2 U or less), CT scan injury scale grade of 1 or 2 without a blush, and patients younger than 55 years. For instances in which patients have significant injury to other systems, surgical intervention may be considered even in the presence of the previously noted findings. Patients on anticoagulants, such as warfarin (Coumadin), and antiplatelet drugs, such as clopidogrel (Plavix), are clinically considered to be at an increased risk for delayed bleed, but this has not yet been confirmed in the surgical literature.
Recombinant factor VIIa has been used to avoid surgery in a pediatric patient but in light of both the cost of the drug and the lack of randomized clinical trials should be used only in extreme circumstances where risk of surgery outweighs the risk of massive thrombosis.[11]
A retrospective analysis by Scarborough et al compared the effectiveness of nonoperative management with immediate splenectomy for adult patients with grade IV or V blunt splenic injury. The study found that both approaches had similar rates of in-hospital mortality (11.5% in the splenectomy group vs 10.0%), however, there was a higher incidence of infectious complications in the immediate splenectomy group. The rate of failure in the nonoperative management was 20.1% and symptoms of a bleeding disorder, the need for an early blood transfusion, and grade V injury were all early predictors of nonoperative management failure.[12]
Splenic angioembolization is increasingly being used in both stable responders and transient responders for fluid resuscitation under constant supervision by a surgeon with an operating room on standby. Femoral artery access with embolization of the splenic artery or its branches can be accomplished with gel foam or metal coils. Such treatment requires intimate cooperation between the trauma surgeon and the interventional radiologist. Not all hospitals will have the proper facilities for such treatment, and any surgeon contemplating splenic angioembolization for a patient should first make sure the hospital interventional radiology suite and personnel are set up for rapid response at any hour of the day.
Surgical therapy is usually reserved for patients with signs of ongoing bleeding or hemodynamic instability. In some institutions, CT scan–assessed grade V splenic injuries with stable vitals may be observed closely without operative intervention, but most patients with these injuries will undergo an exploratory laparotomy for more precise staging, repair, or removal. Adult surgeons may be more likely to operate in cases of splenic injury but less likely to transfuse than their pediatric surgical colleagues.[13]
Emergency celiotomy for hemoperitoneum with suspected splenic injury is performed through a midline abdominal incision. Subcostal or chevron incisions do not provide the opportunity to easily explore the lower abdomen for a hemorrhage site and cannot be performed as rapidly as a midline incision under emergency circumstances. Intestinal and mesenteric injuries may be missed, or they may be difficult to repair appropriately with subcostal incisions.
The splenic ligamentous attachments are taken down sharply or bluntly to allow for rotation of the spleen and the vasculature to the center of the abdominal wound and to identify the splenic artery and vein for ligation. Medial rotation also makes exposure of the hilum of the spleen easier and allows for possible identification of the splenic artery bifurcation. Once the splenic artery and vein are identified and controlled by ligation, the short gastric vessels are identified and ligated in similar fashion.
Ligating the splenic artery first, followed by the splenic vein, has the theoretical advantage of allowing some conservation of intrasplenic blood. In an emergency life-threatening situation, the amount of blood conserved is not worth the extra time it may take to isolate the vessels. Drains are typically unnecessary unless concern exists over injury to the tail of the pancreas during operation.
In less emergent situations, splenorrhaphy is the preferred method of surgical care. Multiple techniques are described in the literature, but they all attempt to tamponade active bleeding either by partial resection and selective vessel ligation or by putting external pressure on the spleen via an absorbable mesh bag or sutures. Both "make it yourself" and commercial products are available for this purpose. In patients with capsular injury, the electrocautery or argon beam coagulator device may provide adequate hemostasis and allow for splenic preservation.
A retrospective analysis by Wu et al compared the use of radiofrequency ablation (RFA) plus suture repair for splenic preservation with traditional splenic preservation surgery in 129 patients with traumatic splenic rupture. For the 35 patients receiving RFA plus suture repair, the mean time of operation was shorter (79 min ± 22 min vs 119 min ± 26 min); there was less bleeding during surgery (115 mL ± 67 mL vs 235 mL ± 155 mL); and there was less need for intraoperative transfusion (14% vs 36%). The RFA group also had significantly less postoperative bleeding and shorter hospital stays (7.1 days ± 1.4 vs 11.7 days ± 2.8).[14]
As most operations for splenic injury are a result of patient instability, standard emergency protocols are instituted, including obtaining 2 wide-bore (16F or larger) IVs for vascular access, 4-6 units of blood for surgery, nasogastric or orogastric tubes for decompression, and a Foley catheter to monitor urine output. Extensive blood work or coagulation profiles are rarely helpful in the emergent setting.
Good communication with the anesthesiologist minimizes the chances for iatrogenically induced problems. Opening the midline fascia on entry into the belly often results in decreasing pressure on the damaged spleen and increased bleeding with hypotension. Keeping the anesthesiologist informed of surgical progress and actions can minimize potential complications of this nature. In most trauma situations, all 4 quadrants of the abdomen are packed with laparotomy pads, which are removed as the search for the bleeding site commences. Presence of a splenic injury on CT scan does not preclude the potential of a bleeding mesenteric tear, consequently, all patients should have a thorough examination of the abdomen—even if preoperative studies show an isolated splenic injury.
The postoperative course is usually 5-14 days, depending on associated injuries. Recurrent bleeding in the case of splenorrhaphy or new bleeding from missed or inadequately ligated vascular structures should be considered in the first 24-48 hours. The author's practice is to maintain a nasogastric tube on low intermittent suction for 48 hours to minimize the risk of a ligature failure on short gastrics with a distended stomach. Other authors prefer to suture ligate the short gastric vessels and to keep a nasogastric tube on low continuous suction to avoid this problem.
Patients should also be evaluated for immunizations against Pneumococcus species as a routine of postoperative management. Some authors and some centers also routinely vaccinate for Haemophilus and Meningococcus species. Various authors suggest immunization should be administered anywhere from 24 hours after injury to 2 weeks, citing studies of the improved physiologic response from vaccination after the immediate postoperative period. This must be weighed against the possibility of loss of follow-up care and missing the vaccination entirely. The author's practice is to immunize all patients prior to discharge.
The US Centers for Disease Control and Prevention (CDC) recommends revaccination with pneumococcal vaccine after 4-5 years one time only. A third booster is not recommended because there is no proof it improves protection from postsplenectomy sepsis, but there is proof that it may cause serious adverse effects. Splenic function is difficult and expensive to measure. Unfortunately, little current data exist regarding the efficacy of surgical treatment, whether operative or conservative.
Patients should be warned about the increased risk of postsplenectomy sepsis and should consider lifelong antibiotic prophylaxis for invasive medical procedures and dental work. Although the lifelong incidence of postsplenectomy sepsis has been estimated to be 0.03-0.8%, the mortality rate of those developing the complication approaches 70%. Adequate education of the signs and symptoms of pneumococcal infection should be stressed.
Complications of nonoperative care include delayed bleeding, splenic cyst formation, and splenic necrosis. Complications of splenorrhaphy include rebleeding and thrombosis of the residual spleen as well as complications related solely to the laparotomy.
Complications of splenectomy include bleeding from short gastrics or splenic vessels and the most feared but most rare complication, infection by encapsulated organisms such as Pneumococcus.
Material used for compression wrap of the spleen in splenorrhaphy is often woven and may mimic bubbles in an abscess on postoperative CT scans. Gel foam used for angioembolization may also falsely mimic an abscess on CT scans. Communication with the radiologist about the presence of splenic wrapping material on any postoperative CT scans will decrease the chance of this false-positive result.
Accessory splenic tissue and reimplantation of splenic tissue have never been reliably proven to minimize the risk of postsplenectomy sepsis. Once the spleen has been removed, patients should be considered to be at risk for encapsulated organism infections for the rest of their lives. Shatz et al noted improved postoperative response to immunization at day 14, with subsequent studies showing no further improvement at day 28.[15, 16]
Angioembolization of the spleen can result in noninfectious-related febrile events, sympathetic pleural effusions, and left upper quadrant abscesses. Femoral arteriovenous fistulas and iliofemoral pseudoaneurysms have also been reported.[17, 18]
Posttraumatic splenic pseudocysts are being reported more frequently now that nonoperative management has become the norm.[19] Optimal management is still unknown but probably requires partial or complete splenectomy to minimize morbidity and mortality.
Splenic abscesses and pancreatitis with sterile abscesses are being reported more frequently with Gelfoam embolization and with more proximal embolization procedures.[20, 21]
Thrombocytosis with platelet counts above 1 million/mm3 have been linked to thrombotic vascular events such as deep vein thrombosis, pulmonary embolus, or occlusive stroke. Although very little good data exist, many surgeons treat persistent thrombocytosis with a daily baby aspirin.
Pancreatic injury, pancreatitis, subphrenic abscess, gastric distension, and focal gastric necrosis have also been reported after both angioembolization and splenectomy for trauma.
Recent multi-institutional studies by the Eastern Association for the Surgery of Trauma demonstrate that mortality from splenic injury still occurs, even in Level 1 trauma centers. Overall, outcome from grade 1-2 splenic injuries remains excellent but not perfect, and outcome worsens as the injury grade increases.
Prognosis is usually excellent, but those patients left asplenic by their injuries and surgery increase the risk of fatal and debilitating infection for the remainder of their lives.
Numerous papers have recently emerged in the literature comparing the practice and the outcome in different levels of trauma centers and comparing trauma and nontrauma centers.[22, 23, 24]
The risk of complications or failure of nonoperative management appears to be worse in patients older than 55 years, and women older than 55 years are significantly more likely to fail nonoperative management with an increased mortality.
Multisystem injury or concomitant liver, pancreas, or bowel injury increases the likelihood of splenectomy. Improved splenic trauma care and salvage rates can be shown in both trauma centers and nontrauma centers, though treatment pattern differences are evolving. Operative treatment with isolated injury is more likely at low-volume centers, but overall salvage rates for nonoperative management are similar between low- and high-volume centers.
Isolated splenic injury is more likely to have nonoperative or interventional radiologic management in a trauma center, but observant management is also more costly in these centers. Patients with multisystem injury in informal and formal trauma systems are more likely to be transferred to a trauma center, and splenic salvage rates in these patients are less than with isolated injury.
Improvements in diagnostic technology, such as helical CT scanners and portable ultrasound, will go far to diagnose and stratify risk in patients with splenic injury. Future multi-institutional trials and data collection may make it possible to better identify those patients at risk for persistent bleeding and to minimize the need for operative intervention and splenectomy in all but a few patients. Improvements in knowledge of immunology may lead to more effective immunizations for patients who are asplenic and further minimize their risk of deadly infection.
Increased availability and ease of access to interventional radiologic equipment and personnel, especially in rural hospitals, may salvage splenic injuries that previously required operative intervention and splenectomy.
The controversy over when to operate, when to embolize and when to observe will likely continue for the next millennium, but the debate will spur the continued development of diagnostic and evaluative tools, further minimizing morbidity and mortality caused by splenic injury.