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Indications & Contraindications
Patient selection, fracture classification, bleeding source
Indications
- Pelvic fracture with arterial contrast blush on CTA — active extravasation requiring embolization
- Hemodynamic instability with pelvic fracture after external fixation / pelvic binder has been applied and bleeding persists
- Large pelvic hematoma with clinical deterioration despite resuscitation
- Bleeding source: internal iliac artery branches — superior gluteal, obturator, internal pudendal, and lateral sacral arteries are most commonly injured
Contraindications
- Isolated venous bleeding — not amenable to embolization; requires packing or pelvic binder
- Hemodynamically unstable with abdominal source requiring laparotomy first (evisceration, free air, bowel ischemia)
- Cancellous bone bleeding only — not fixable with embolization (orthopedic fixation required)
Pelvic Fracture Classification
| Fracture Pattern | Mechanism | Vascular Injury Risk | Vessel to Target |
|---|---|---|---|
| APC II–III (open book) | Anterior compression — widens pubic symphysis >2.5 cm, disrupts SI ligaments | HIGH — posterior pelvic arterial disruption | Superior gluteal > internal pudendal > lateral sacral |
| LC II–III (lateral compression) | Lateral force — crescent fracture, SI disruption, posterior instability | MODERATE–HIGH — posterior + anterior division | Internal pudendal, obturator, superior gluteal |
| VS (vertical shear) | Vertical displacement — complete hemipelvic instability | HIGHEST — bilateral IIA injury common | Bilateral IIA embolization often required |
| APC I / LC I | Minor disruption — partial ligament injury, pubic rami fractures | LOW | Arterial injury uncommon; embolization rarely needed |
| Acetabular fracture | High-energy axial load | MODERATE — superior gluteal or obturator | Superior gluteal, obturator, corona mortis variant |
Key principle: Fracture classification predicts likelihood but not location of arterial injury — bilateral pelvic angiography is mandatory regardless of laterality on CTA. Up to 30% of angiographic bleeding sources are missed on CTA.
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Pre-Procedure Planning
CTA review, resuscitation, team coordination
Imaging & Labs
- CTA pelvis — multiphase protocol; identify active arterial extravasation, hematoma size, fracture pattern, vascular variants (corona mortis)
- Review fracture pattern: Young-Burgess / Tile classification guides expected bleeding sites
- Type & screen / crossmatch — MTP likely active
- CBC, BMP, coags, lactate, ABG — trending hemoglobin, base deficit, INR
- CTA sensitivity 80–94% for active arterial hemorrhage (higher with 64-row multidetector CT)
Resuscitation & Coordination
- Pelvic binder / external fixation ALREADY applied before IR suite
- Massive transfusion protocol (MTP) activated — 1:1:1 ratio RBC:FFP:platelets
- REBOA consideration if patient crashing — zone 3 placement (infrarenal aorta to bifurcation) can temporize arterial hemorrhage
- Foley catheter placed — prevents contrast-filled bladder from obscuring pelvic vasculature
- Communicate with orthopedic trauma and general surgery — multidisciplinary decision on IR vs OR vs both
CTA reviewed. Active extravasation site(s) identified, fracture pattern classified, vascular anatomy mapped including variants.
Pelvic binder / external fixation in place. Confirmed not obstructing femoral access.
MTP active. Blood products available in IR suite. Type & screen completed.
Foley catheter placed. Bladder decompressed to prevent contrast obscuration.
Anesthesia at bedside. GA or deep sedation anticipated. Vasopressors and fluid resuscitation ongoing.
Surgical team aware. Ortho trauma and general surgery notified; plan for post-embolization care established.
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Relevant Anatomy
Internal iliac artery branches, anterior & posterior divisions
Internal Iliac Artery — Posterior Division
- Superior gluteal artery — most commonly injured branch in pelvic trauma; exits greater sciatic foramen above piriformis
- Iliolumbar artery — courses posterosuperiorly to iliac fossa and lumbar spine
- Lateral sacral arteries — descend along sacral foramina; injury associated with sacral fractures
Internal Iliac Artery — Anterior Division
- Obturator artery — courses through obturator foramen; commonly injured in pubic rami fractures
- Internal pudendal artery — exits through greater sciatic foramen, re-enters via lesser sciatic foramen
- Inferior gluteal artery — exits greater sciatic foramen below piriformis, near sciatic nerve
- Middle rectal, inferior vesical, vaginal, and uterine arteries
- Umbilical artery / superior vesical artery — branch of obturator
Key Anatomic Variants
- Corona mortis — anastomosis between external iliac / inferior epigastric and obturator artery; present in ~29% of patients (11% bilateral); vulnerable in pubic rami fractures
- Aberrant obturator artery — arises from inferior epigastric artery in ~33% of patients without IIA connection; crosses superior obturator foramen
- Significant variability in branching order and origin of IIA branches
Bilateral Supply
- Always check both sides — bilateral IIA angiography is mandatory even if CTA shows unilateral bleeding
- Fracture-related hemorrhage often involves multiple branches on both sides
- Rich pelvic collateral network: bilateral IIA embolization is well-tolerated with temporary embolic agents (Gelfoam)
- Venous bleeding (presacral plexus, prevesical veins) mirrors arterial anatomy but is NOT amenable to embolization
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Technique
Access, catheterization, embolic selection, embolization strategy
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Access
Common femoral artery (CFA) access, preferably contralateral to the most injured side. Ensure pelvic binder is not obstructing femoral access. If bilateral CFA inaccessible due to trauma or instrumentation, upper extremity access via radial artery is an alternative.
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Initial Nonselective Pelvic Angiogram
Place catheter just above the aortic bifurcation. Perform nonselective aortogram/pelvic angiogram to visualize entire pelvis and assess for large vessel injury. Include proximal superficial femoral arteries bilaterally to evaluate pelvic arterial variants.
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Selective Bilateral IIA Catheterization
Use a 5F Cobra or RUC to selectively catheterize each IIA. Bilateral pelvic angiogram is mandatory regardless of CTA findings — CTA misses up to 30% of pelvic bleeding sources seen on angiography.
Contralateral IIA (from right CFA access): Standard Cobra/RUC across the bifurcation. Contralateral oblique view (CAO 30°) to open the IIA origin.
Ipsilateral IIA — Waltman Loop:
Use ipsilateral oblique (30–45°) for anterior/posterior division separation. Multiple projections essential — bleeding, AVF, pseudoaneurysm, and dissection all require orthogonal views to characterize.
Contralateral IIA (from right CFA access): Standard Cobra/RUC across the bifurcation. Contralateral oblique view (CAO 30°) to open the IIA origin.
Ipsilateral IIA — Waltman Loop:
- Retract catheter to the distal aorta, tip pointing cephalad.
- Advance with clockwise torque — tip buckles off the opposite aortic wall, forming a reverse-curve loop.
- Pull back slowly: in reverse-curve, traction paradoxically advances the tip into the ipsilateral IIA.
- Confirm position with contrast injection before proceeding to superselection.
Use ipsilateral oblique (30–45°) for anterior/posterior division separation. Multiple projections essential — bleeding, AVF, pseudoaneurysm, and dissection all require orthogonal views to characterize.
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Superselective Branch Catheterization
Advance microcatheter into the bleeding branch for targeted embolization. Identify active extravasation, pseudoaneurysm, or vessel disruption. If multiple bleeding sites identified, prioritize the largest source first.
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Embolization
Gelfoam (preferred) — temporary occlusion; vessels typically recanalize within weeks; safe for bilateral IIA embolization due to rich pelvic collaterals. Gelfoam slurry for diffuse small vessel bleeding; Gelfoam torpedoes (2–3 mm strips via 1 mL syringe) for superselective embolization of larger vessels. Coils — for focal pseudoaneurysm or large vessel injury; permanent occlusion; can limit future access if rebleeding occurs. Non-selective anterior division embolization with Gelfoam if patient is hemodynamically unstable with multiple bleeding sites — faster to achieve hemostasis than multiple superselective embolizations.
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Bilateral Embolization
Bilateral embolization is often needed. After treating the primary side, catheterize and perform angiography of the contralateral IIA. Embolize any additional sources of hemorrhage. With Gelfoam, bilateral IIA embolization is safe and well-tolerated.
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Completion Angiography
Repeat pelvic angiogram to confirm hemostasis. Assess for residual extravasation or new bleeding sites unmasked after treatment of initial hemorrhage. Remove catheter and obtain hemostasis at access site.
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Landmarks
Key angiographic landmarks for pelvic embolization
Arterial Landmarks
- IIA bifurcation — internal iliac artery divides into anterior and posterior divisions at the superior aspect of the sacroiliac joints
- Anterior division — gives rise to obturator, inferior gluteal, internal pudendal, middle rectal, inferior vesical, vaginal/uterine arteries
- Posterior division — gives rise to superior gluteal, iliolumbar, and lateral sacral arteries
Key Branches to Identify
- Superior gluteal artery — largest branch of posterior division; exits pelvis through greater sciatic foramen above piriformis; most commonly injured in pelvic trauma
- Obturator artery — courses through obturator foramen; frequently injured with pubic rami fractures; check for corona mortis variant
- Internal pudendal artery — terminal branch of anterior division
- Lateral sacral arteries — enter sacral foramina; injured with sacral fractures
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Troubleshooting
Intraoperative problems and solutions
No Active Extravasation on Angiogram
CTA Showed Blush but Angiogram Is Negative
A negative angiogram does NOT exclude ongoing hemorrhage. Vasospasm from vasopressors or intermittent hemostasis can mask active bleeding. Perform empiric Gelfoam embolization of the anterior division bilaterally if CTA was positive. Decision to embolize empirically should be based on clinical judgment and prior CTA findings. Gelfoam is safe for empiric use given its temporary nature.
Ongoing Hemodynamic Instability
Patient Remains Unstable After Embolization
Consider that pelvic fracture bleeding is often multifactorial. Venous bleeding (presacral plexus, prevesical veins) and cancellous bone bleeding are NOT fixable with embolization. Communicate with surgery for preperitoneal pelvic packing. Check for additional sources: splenic injury, liver laceration, retroperitoneal hematoma from other source. Repeat angiography if arterial source suspected but not treated.
Coagulopathy
Persistent Bleeding Despite Embolization — Suspect Coagulopathy
Trauma-induced coagulopathy is common. Continue MTP with 1:1:1 ratio. Correct hypothermia (lethal triad: hypothermia, acidosis, coagulopathy). Consider TXA if within 3 hours of injury. Check TEG/ROTEM if available. Embolization will be less effective if coagulopathy is uncorrected.
Access Difficulty
CFA Inaccessible Due to Pelvic Binder or Groin Trauma
Adjust pelvic binder to expose femoral pulse while maintaining pelvic compression. If both groins are inaccessible, use upper extremity access via radial artery with long catheter/sheath system. Ultrasound guidance for CFA access in trauma patients is strongly recommended.
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Complications
Post-embolization complications and management
Ischemic Complications
- Gluteal necrosis — rare with Gelfoam (temporary occlusion); higher risk with permanent embolic agents and bilateral IIA embolization with coils/particles
- Sciatic nerve ischemia / paralysis — from embolization of lateral sacral or sciatic nerve arteries; monitor lower extremity motor/sensory function post-procedure
- Bladder necrosis — rare; risk increases with bilateral permanent IIA embolization
- Skin necrosis — nontarget embolization with small particles to cutaneous branches
Other Complications
- Rebleeding — ~24% may require repeat angiography, 19% need repeat embolization; risk factors: initial Hgb <7.5, elevated INR, >6 units pRBC post-embolization, injury to ≥2 vessels, superselective embolization technique
- Impotence — risk with bilateral permanent IIA embolization (coils); minimized with Gelfoam (temporary)
- Nontarget embolization — Gelfoam particles to pelvic muscles, skin, or visceral branches causing capillary occlusion
- Access site complications — hematoma, pseudoaneurysm (coagulopathic patients at higher risk)
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Pearls & Pitfalls
High-yield tips for pelvic trauma embolization
✦
Pelvic fracture bleeding is often VENOUS and from BONE (cancellous bleeding), not arterial. Embolization only fixes the arterial component. Set expectations with the trauma team — embolization alone may not achieve hemodynamic stability.
✦
Pelvic binder FIRST, then embolization. Mechanical stabilization reduces pelvic volume and tamponades venous/bone bleeding. Embolization addresses what the binder cannot — arterial hemorrhage.
✦
Gelfoam is the ideal embolic agent for pelvic trauma. Temporary occlusion allows vessel recanalization within weeks. Bilateral IIA embolization with Gelfoam is safe due to the rich pelvic collateral network. Permanent agents (coils, particles) carry higher risk of ischemic complications.
✦
Can embolize empirically if CTA is positive but angiogram is negative. Vasospasm and intermittent hemostasis can mask active bleeding. Empiric Gelfoam to the anterior division bilaterally is a reasonable approach.
✦
Superior gluteal artery = most commonly injured branch. It is the largest branch of the posterior division and exits the pelvis through the greater sciatic foramen above the piriformis.
⚠
Delays >3 hours to embolization are associated with increased mortality. Early activation of the angiography suite is critical. One study estimated 80% of mortality was attributable to delays in achieving hemostasis.
⚠
Do not assume angiogram-negative means no arterial bleeding. Vasopressors can induce vasospasm masking the hemorrhage source. Always correlate with CTA findings and clinical picture before deciding against embolization.
⚠
Avoid bilateral permanent IIA embolization with coils/particles when possible. Risk of gluteal necrosis, impotence, and bladder necrosis is significantly higher with permanent agents compared to Gelfoam.
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References & Resources
Primary sources and guidelines
Primary References
- Velmahos GC, Toutouzas KG, Vassiliu P, et al. A prospective study on the safety and efficacy of angiographic embolization for pelvic and visceral injuries. J Trauma. 2000;49(3):496–502.
- Costantini TW, Coimbra R, Holcomb JB, et al. Current management of hemorrhage from severe pelvic fractures: results of an American Association for the Surgery of Trauma multi-institutional trial. J Trauma. 2010;73(6):1459–1463.
- Leslie JF, Smirniotopoulos JB. Pelvic trauma: anatomy and interventions. Semin Intervent Radiol. 2025;42(2):139–143.
- Coccolini F, Stahel PF, Montori G, et al. Pelvic trauma: WSES classification and guidelines. World J Emerg Surg. 2017;12:5.
- Tesoriero RB, Bruns BR, Narayan M, et al. Angiographic embolization for hemorrhage following pelvic fracture: is it “time” for a paradigm shift? J Trauma Acute Care Surg. 2017;82(1):18–26.
- Franco DF, Zangan SM. Interventional radiology in pelvic trauma. Semin Intervent Radiol. 2020;37(1):44–54.
- El Khudari H, Abdel Aal AK. Endovascular management of pelvic trauma. Semin Intervent Radiol. 2021;38(1):123–130.