Chronic Subdural Hematoma

Our Specialists for Chronic Subdural Hematoma

Chronic subdural hematomas are the bread and butter of emergency neurosurgery, but the right operation for the right patient is not always obvious — especially in elderly patients on blood thinners or those whose hematomas keep coming back. Our trauma and neurovascular teams work together daily, offering the full range of options from bedside twist-drill drainage to middle meningeal artery embolization.

Paramita Das, M.D., M.S.

Director, Neurotrauma; Director, Neurosurgical Trauma Fellowship

Dr. Das is Director of Neurotrauma at UChicago's Level 1 Trauma Center and directs the Neurosurgical Trauma Fellowship, one of only a few dedicated neurosurgical trauma fellowships in the country. She manages both head trauma and acute spine pathology and has been named to the Bucksbaum-Siegler Institute for Clinical Excellence. She trained at the University of Minnesota for residency and completed a skull base fellowship at Cleveland Clinic. As Director of Surgical Neurotrauma at UChicago, Dr. Das sees more chronic subdural hematomas than any other surgeon on the team, and she leads the decision-making on which patients get a bedside twist-drill versus a formal burr hole versus a combined procedure with MMA embolization. Her research focuses on outcomes and biomarkers after traumatic brain injury in older adults, the exact population most affected by cSDH.

P. B. Raksin, M.D.

Associate Program Director, Neurological Surgery Residency

Dr. Raksin is an Associate Professor of Neurological Surgery and serves as Associate Program Director of the UChicago Neurological Surgery residency program. She is a senior clinician within the department and contributes broadly to resident education and general neurosurgical care. Dr. Raksin is one of the country's most respected voices in acute care neurosurgery — she co-edited the Atlas of Emergency Neurosurgery and Acute Care Neurosurgery by Case Management, both of which include detailed chapters on chronic subdural management. If you have a chronic subdural hematoma at UChicago Medicine or our partner trauma centers, she is one of the attendings most likely to be at the bedside.

What Is a Chronic Subdural Hematoma?

A chronic subdural hematoma is a collection of old blood that sits on the surface of the brain, underneath the tough outer covering called the dura. Unlike the acute bleeds you see after a bad car accident, a chronic subdural builds up slowly — typically over two to six weeks — and the blood inside has usually broken down into a thin, motor-oil-colored fluid by the time it is discovered.

These bleeds usually start when the small bridging veins that run between the brain and the dura get stretched and tear. In older adults, the brain naturally shrinks a little with age, which pulls those veins tight and makes them much more vulnerable. A trip on a rug, a bumped head on a cabinet, or even no clear trauma at all can be enough to start one — and patients often do not remember the event.

Chronic subdural hematoma has become one of the most common reasons older adults end up in a neurosurgeon's office. As the population ages and more people take blood thinners for heart and stroke prevention, the number of cases keeps climbing. Some experts now call it the most common neurosurgical condition of the elderly.

The encouraging news is that, once recognized, cSDH is usually very treatable. Most patients walk out of the hospital within a few days of surgery, and the majority return to their previous level of function.

What Does It Feel Like?

Chronic subdural hematomas are sneaky. Because the bleed builds up slowly, the brain has time to accommodate the pressure, and early symptoms can look like almost anything — dementia, a small stroke, a medication side effect, or just "slowing down with age." That's why family members are often the first to notice that something is off.

Common symptoms

• Headache — often mild at first, sometimes worse when lying flat or in the morning
• Confusion or memory trouble — new forgetfulness, word-finding problems, or personality changes
• Weakness on one side — a drooping arm, a dragging foot, or a hand that suddenly has trouble with buttons
• Unsteady walking or falls — a wide, cautious gait that is new for the patient
• Sleepiness — hard to rouse, dozing off during conversations
• Slurred speech or trouble finding words
• Seizures — less common, but can be the first clue

When to go to the ER

Any older adult — especially someone on a blood thinner — who develops new headache, new weakness, new confusion, or a change in walking after a fall (even weeks earlier) should get a head CT. It takes 10 minutes and it can be life-saving.

How Is It Diagnosed?

The diagnosis is almost always made with a non-contrast CT scan of the head, which is fast, widely available, and does not require a needle. On CT, a chronic subdural typically appears as a crescent-shaped collection draped over the surface of the brain. The color of the blood on the scan tells the story of how old it is: bright white means fresh, dark gray means old and liquefied, and mixed densities mean the hematoma has been bleeding again on top of an older collection.

An MRI is sometimes added to sort out tricky cases — for example, when the hematoma is small, when there are membranes dividing the collection into compartments, or when the surgeon is trying to decide whether it will drain easily through a small opening.

Along with imaging, the team will:

• Check your blood thinners and platelet count — most patients are on aspirin, clopidogrel, warfarin, or one of the newer direct oral anticoagulants, and these may need to be temporarily reversed before surgery
• Look at your neurologic exam to decide how urgent the operation is
• Review the size of the hematoma, how much it is pushing the brain toward the other side (called midline shift), and whether there is fresh bleeding inside the collection

Small, asymptomatic chronic subdurals in patients with no blood thinners can sometimes be managed without surgery, with a repeat scan in a few weeks. Symptomatic ones almost always need to be drained.

How Is It Treated?

Treatment has two goals: get the old blood out, and keep it from coming back. For decades the first goal was the focus of attention. In the past few years, a new set of randomized trials has transformed how we think about the second.

Burr hole drainage — the workhorse

For most symptomatic patients, the first-line treatment is burr hole craniostomy with placement of a subdural drain. Under anesthesia, the surgeon makes one or two small openings in the skull — each about the size of a nickel — washes out the old blood, and leaves a soft drain in place for one to two days. It is a short procedure (often under an hour), the recovery is usually fast, and most patients go home within three to five days.

Two landmark trials refined this operation. The Cambridge drain trial (Santarius, Lancet 2009) showed that leaving a drain for 48 hours cut the recurrence rate nearly in half and reduced mortality at 6 months. More recently, the FINISH trial (Raj, Lancet 2024) showed that irrigating the subdural space with saline during the operation also reduces reoperation rates compared to drainage alone. Both steps — irrigation and a drain — are now standard at UChicago.

Twist drill craniostomy and SEPS

For frail patients, those who cannot tolerate general anesthesia, or those whose hematomas are thin and free-flowing, there are even smaller procedures:

• Twist drill craniostomy uses a hand-held drill to make a 3-5 mm hole in the skull, often at the bedside with only local anesthesia. A thin catheter is then passed into the subdural space to drain the blood over one or two days.
• Subdural evacuating port system (SEPS) — a commercially available version of the same idea (Medtronic), using a hollow screw threaded into the skull that connects to a negative-pressure bulb. It can be done in the ICU with a local numbing injection, and is especially useful for patients who are medically too fragile for the operating room.

These techniques have lower up-front risk than a burr hole, but they also have somewhat higher recurrence rates — which is exactly where the next technique comes in.

Middle meningeal artery (MMA) embolization — the biggest advance in a generation

For as long as neurosurgeons have been draining subdurals, about 10 to 20 percent of patients have needed a second operation because the hematoma came back. The culprit is the outer membrane of the hematoma, which grows a web of fragile new blood vessels that keep re-bleeding. Those vessels are fed by the middle meningeal artery — an artery that runs on the inside of the skull and can be reached through a catheter from the groin or wrist.

In MMA embolization, an endovascular neurosurgeon threads a tiny catheter up to the middle meningeal artery and injects liquid embolic material or small particles to close off those feeder vessels. The procedure takes about an hour, involves no incision in the head, and most patients go home the next day.

In the past year, three major randomized trials have established MMA embolization as a true game-changer:

• EMBOLISE (Davies, NEJM 2024) — in patients having surgery for a symptomatic chronic subdural, adding MMA embolization cut the rate of hematoma recurrence or progression needing reoperation from about 11% to about 4%.
• MAGIC-MT (Liu, NEJM 2024) — a Chinese trial in both surgical and non-surgical patients. Embolization did not beat standard care on the primary endpoint, but there were fewer serious adverse events in the embolization group.
• STEM (Fiorella, NEJM 2025) — MMA embolization with SQUID liquid embolic cut the rate of treatment failure roughly in half compared to standard care alone.

At UChicago, we now routinely offer MMA embolization — either as an adjunct to surgery for patients with a high risk of recurrence (big hematomas, bilateral hematomas, patients on lifelong blood thinners) or, occasionally, as a stand-alone treatment for smaller, less symptomatic collections.

What about dexamethasone or other medications?

Steroids were tried for years on the theory that inflammation drives hematoma regrowth. The Dex-CSDH trial (Hutchinson, NEJM 2020) settled the question: patients who received a two-week dexamethasone taper had worse functional outcomes and more complications than those who got placebo, even though they had slightly fewer reoperations. Routine steroid use for chronic subdurals is no longer recommended.

Managing blood thinners

One of the most delicate parts of treating chronic subdural hematoma is deciding what to do about the blood thinners that contributed to the bleed in the first place. We work closely with cardiology, stroke, and hematology to individualize this — pausing and reversing medications around surgery, then carefully restarting them at the right time to minimize the risk of both re-bleeding and stroke.

What Are the Outcomes?

Most patients with chronic subdural hematoma do well. With prompt surgery, symptoms usually improve within days to weeks, and the majority of patients return to their previous level of independence. That said, cSDH is not a benign disease — it is a marker of aging, frailty, and fall risk, and the long-term survival numbers reflect that as much as they reflect the surgery itself.

Reoperation rates

The rate at which a chronic subdural hematoma comes back and requires a second drainage has been the central problem in the field for decades. Here is what the modern data show:

Functional recovery

Roughly 80 percent of patients return to their pre-bleed level of function after surgery, and most of the improvement happens in the first few weeks. Recovery is slower in patients who were already frail, who had severe symptoms on arrival (for example, inability to speak or move one side), or who had large hematomas with significant midline shift.

A short course of inpatient rehab or home physical therapy is common after discharge, especially for patients who were already unsteady on their feet. Driving is usually held for several weeks until the brain has re-expanded and the surgeon clears the patient.

Mortality in the elderly

Short-term surgical mortality is low — typically around 2 to 5 percent. But longer-term survival is more sobering. In population-based studies, the one-year mortality after chronic subdural hematoma in elderly patients is roughly 25 to 30 percent, and at five years it approaches 50 percent. Most of those deaths are not from the hematoma itself but from the underlying conditions that led to the fall in the first place: heart disease, cancer, dementia, and frailty.

What that means in practical terms is that for an older adult, a chronic subdural is a wake-up call, not just a surgical problem. Our team tries to treat it as an opportunity to tune up everything else: review medications, reassess fall risk at home, rebalance blood thinners, and loop in the patient's primary care physician for a broader plan.

The single biggest factor you can control is getting to an experienced team quickly. At UChicago, our trauma and neurovascular surgeons work as one unit — the same on-call group who does a burr hole at 2 a.m. can have an endovascular surgeon ready to embolize the middle meningeal artery the next morning.

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