What this is
Working notes on acetabular tumour embolisation: the anatomy on screen, why the pelvis demands more care than most sites, and the logic behind using coils before particles. Written from the vantage of someone in the room assisting, trying to understand what’s happening and why.
Why This Patient Is Here
Most of the time, this case is about pain. The patient has cancer that’s spread to the acetabulum (the cup-shaped socket in the pelvis that the hip sits inside) and it’s not controlled by medication alone. The tumour has recruited a dense blood supply to feed itself, and that vascularity is part of what makes it hurt. More blood flow means more swelling, more pressure on the bone from the inside, and more of the chemical signals that keep pain nerves firing.
The goal is to cut that supply off. Think of it like turning off the water to a leaking pipe. What’s already there stays for a while, but nothing new is coming in, and the pressure drops. When the tumour loses its blood, it starts to die off, the swelling reduces, and those pain-driving chemicals stop being produced. Most patients notice the difference within a day or two, though the full effect takes a couple of weeks.
The literature tends to frame this as a preoperative procedure, something done before surgery to reduce bleeding on the table. That’s a real application. But a lot of the patients who come through for this aren’t having surgery at all, embolisation is the treatment. The technique is the same either way.
What pain relief looks like
Around 60–80% of patients get meaningful relief. It’s not permanent. Collateral vessels (backup pathways) can grow in over months and the tumour regains some supply. Repeat embolisation is common at the 3–6 month mark if the disease is stable and the pain has returned.
The Vessels on Screen
The acetabulum (say it: ass-tab-you-lum) sits at an inconvenient crossroads. Three separate vascular territories converge there: the pelvic visceral supply, the gluteal supply to the buttock and hip, and the proximal femoral supply. The result is that most tumours in this area receive blood from multiple vessels, each one needing to be dealt with separately.
The feeders the doctor is mapping on screen come from branches of the internal iliac artery, the major artery supplying the inside of the pelvis. The main ones are the superior gluteal artery, which runs to the back of the hip and is usually the dominant feeder. The inferior gluteal artery goes to the lower hip, capsule, and upper hamstrings. The obturator artery feeds the medial wall of the hip joint. And the iliolumbar artery varies in how much it contributes but often connects to the others.
When the contrast is injected, the tumour lights up. This is called the blush, and it looks like exactly what it sounds like, a flush of white spreading through the tumour. The brightness tells the doctor how vascular it is. Highly vascular tumours blush as intensely as the normal artery next to them. Those are the ones where embolisation makes the biggest difference.
Worth noticing: the acetabulum almost always has more than one feeder. If only one vessel gets dealt with and the rest are left alone, the patient probably won’t get much relief.
The Connections That Make This Case Careful
The thing about the pelvic arteries is that they don’t stay in their lanes. Several of these vessels connect to each other, and to arteries in territories you have no intention of blocking, through small linking channels. This is what makes an acetabular embolisation methodical compared to a lot of other sites.
Think of it like a city where the back alleys connect streets you don’t expect. If you block one street, you need to know which alleyways lead where, otherwise the consequences end up somewhere you didn’t plan for.
These connections must be identified before any embolic material goes in
Connection What it links What goes wrong if it’s missed Corona mortis Obturator artery ↔ external iliac or inferior epigastric Particles travel to the bladder, bowel, or leg Cruciate anastomosis Inferior gluteal ↔ arteries feeding the femoral head Femoral head loses its blood supply, avascular necrosis (AVN), bone death Iliolumbar–superior gluteal Iliolumbar ↔ superior gluteal Particles travel backward toward lumbar segmental vessels, potentially toward the spinal cord supply Obturator–femoral Obturator accessory branch ↔ femoral territory Femoral nerve or skin ischaemia
The corona mortis (the name means “crown of death,” which surgeons have been applying to it since they started accidentally cutting it during pelvic operations) is present in about 8 in 10 people. It is a connection between the obturator artery inside the pelvis and the external iliac artery that supplies the leg, running right behind the pubic bone. In most acetabular tumours, it is sitting adjacent to the lesion. If it’s open and particles go into the obturator territory, those particles will find it.
The cruciate anastomosis is the other one to understand, particularly in palliative cases where the patient is keeping their hip. It links the inferior gluteal artery to the arteries feeding the ball of the hip joint (the femoral head) through a chain of vessels at the top of the thigh. Particles that drift through that connection deprive the femoral head of blood, and bone without blood dies. In a patient who already has cancer in their pelvis, trading that for a collapsed hip joint is not a good outcome.
How the Case Unfolds
Access goes through the groin, usually the opposite side from the tumour, via the common femoral artery. The doctor uses a shaped diagnostic catheter (you’ll hear names like Cobra or SIM2, which refer to the curve at the tip) to navigate into the internal iliac artery and run contrast to map the feeders. This phase often takes a while. The doctor is building the same picture from inside the vessel that they studied on the CT beforehand: which branches are feeding the tumour, how intense the blush is, and critically, which connecting vessels are present and need to be addressed.
Once the anatomy is mapped, a much finer tube called a microcatheter (a smaller straw inside the outer one) is advanced out to the specific vessel being targeted. Common ones are the Progreat or Renegade. The microcatheter is what allows superselective positioning, which means getting as close to the tumour as possible before anything is delivered. A cone-beam CT (the X-ray arm spinning a full circle around the patient) is increasingly used at this point to confirm the tip is sitting where it needs to be and that there are no untargeted branches that could receive stray particles.
Then comes the sequence that makes this case distinctive: coils first, particles second. More on why below. After the coils are placed in the relevant connecting vessels, the particles are injected slowly while the doctor watches the screen. The goal is stasis, the moment contrast stops flowing because the vessel is blocked. A check angiogram confirms it’s done and nothing has gone astray. Then the microcatheter is repositioned into the next feeder, and the sequence repeats.
By the end, you’ll have watched each contributing vessel (superior gluteal, inferior gluteal, obturator, iliolumbar) get dealt with individually. That’s why these cases run longer than they look like they should on paper.
Why the Coils Go in First
The question you end up asking when you understand the anatomy is: if particles are injected into this vessel, where else could they go? And the honest answer in the pelvis is: a lot of places.
Particles are a suspension, tiny fragments or spheres mixed into saline and contrast and injected into the bloodstream. They travel with flow and lodge in small vessels. That’s the whole point. But as they build up and the target vessel starts to block, pressure rises behind them. That pressure looks for any available escape route. If there is an open connection to another territory (a corona mortis between the obturator and external iliac, or the anastomosis between the inferior gluteal and the femoral head supply), particles will find it and go through.
Coils close those escape routes before the particles are introduced. A coil is a length of metal wire, often with soft fibres threaded through it to help clot form, that is pushed through the microcatheter into the vessel and springs open. Once it’s in place and the vessel is blocked, no amount of injection pressure will move particles past it. The sand can only go where you want it to go.
The logic in one sentence
Coils seal the connecting vessels so that particles, which follow pressure gradients, cannot travel into unintended territories.
There is a variation sometimes used for tumours with very extensive collateral supply: particles go in first to hit the tumour nidus (the core of the lesion), then coils go in proximally at the end to prevent new collateral vessels from growing in quickly. This is about consolidating the result rather than protecting non-target territories. In the acetabulum with its dangerous connections, the protective coiling of the anastomotic vessels still comes before particles regardless.
After the Case
Almost every patient will have what’s called post-embolisation syndrome in the day or two after. Fever, pain at the treated area, nausea, fatigue. It’s the body reacting to a section of tumour dying. It is expected and managed conservatively with analgesia and antiemetics, and it settles. Worth flagging to patients before they go, because waking up feeling significantly worse than before and not knowing why it’s happening is frightening.
The things genuinely worth watching for: any new neurological symptoms in the leg or foot (weakness, numbness, foot drop) which would suggest the sciatic nerve territory has been caught. Changes in the hip joint itself, particularly escalating groin pain in a patient who’s keeping their hip, may indicate the femoral head blood supply has been affected. Bladder or rectal symptoms are rare but possible if the corona mortis wasn’t adequately managed.
For the patients who came in for preoperative embolisation, surgery is ideally within 24 to 72 hours. Earlier than that and there hasn’t been enough time for the ischaemia to take full effect. Later than that and collateral vessels start to compensate, eroding the blood-loss benefit.
Numbers Worth Knowing
| Patients with corona mortis present | ~81% (60–83% across cadaveric series) |
| Arterial corona mortis channels >3 mm | ~60% |
| Expected pain relief rate | 60–80% of patients in observational series |
| Onset of pain relief | 24–72 hours, peak at 1–2 weeks |
| Durability before repeat needed | 3–6 months in many patients |
| Preoperative blood loss reduction (RCC, best evidence) | 1.77 L → 0.90 L (p=0.002), one case-control study |
| Surgical window after embolisation | 24–72 hours |
| Standard particle size for bone | 300–500 µm |
Related
- Liver Tumour Embolisation, same arterial-catheter approach, different territory and different embolic logic
- Bland TAE — Embolisation Agents, deeper look at particles and coils as embolic agents
Sources
- Embolization of Musculoskeletal Bone Tumors — PMC
- Update on Preoperative Embolization of Bone Metastases — PMC
- Preoperative embolization in surgical treatment of long bone metastasis — PMC
- Transarterial Embolization of Bone Metastases — TVIR
- Interventional Management of Hypervascular Osseous Metastasis — AJR
- Preoperative Arterial Embolization of Musculoskeletal Tumors — MDPI
- Musculoskeletal Metastases Management — PMC
- A Case-Based Approach to Common Embolization Agents — AJR
- The Common but Complicated Tool: Review of Embolic Materials — PMC
- Endovascular Embolization by Transcatheter Delivery of Particles — PMC
- Embolic Agents: Particles — PMC
- Corona mortis — Darmanis 2007, Clinical Anatomy
- Corona Mortis variants and implications — PMC
- Corona mortis in pelvic trauma — American JIR
- Complications of Embolization — PMC
- Embolization of hypervascular bone metastases reduces intraoperative blood loss — PubMed
- Contour PVA Embolization Particles — Boston Scientific
Last updated May 18, 2026.