Intercostal Nerve Block for Chest and Abdominal Pain

An intercostal nerve block is an injection of local anesthetic around one or more of the nerves that run along the underside of each rib, numbing a band of chest or upper abdominal wall. It is one of the oldest and most straightforward regional anesthesia techniques, used to control pain from rib fractures, chest surgery, and certain chronic conditions. The procedure delivers fast, targeted relief, but its effects wear off in hours rather than days, and the technique carries a small but real risk of puncturing the lung. How well it stacks up depends heavily on what it is being compared to, what drugs are injected, and whether a single shot or a continuous catheter is used.

How the Procedure Works

Each rib has an intercostal nerve traveling in a groove along its lower border, bundled alongside a small artery and vein. The nerve supplies sensation to the skin, muscles, and lining of the chest wall in a strip-like pattern that wraps from the spine around to the front of the body. When a clinician injects local anesthetic into this groove, the drug bathes the nerve and temporarily shuts down pain signals from that strip. Because each nerve covers only one rib level, blocking pain across several ribs requires separate injections at each level.

The injection is typically placed near the angle of the rib, the bony curve a few inches from the spine, where the nerve is most accessible and not yet hidden behind thick muscle. The patient sits upright or lies on their side, and the needle is advanced just past the lower edge of the rib until it slips into the subcostal groove. The whole thing takes a few minutes per level. Common local anesthetics include bupivacaine and ropivacaine, both chosen for their relatively long duration of action compared to lidocaine.

Ultrasound Has Changed Accuracy Substantially

Traditionally, clinicians performed intercostal nerve blocks using anatomic landmarks alone, feeling for the rib edges with their fingers and estimating needle depth. That approach works, but a cadaver study comparing landmark-guided injections to ultrasound-guided ones found a stark difference: ultrasound achieved correct spread of dye along the nerve about 97% of the time, compared with 70% for the landmark method.¹ Ultrasound also allowed effective blocks with smaller volumes of anesthetic, since the needle could be placed more precisely. In clinical practice, ultrasound guidance is now considered the standard of care when equipment is available, particularly in the emergency department and in patients whose anatomy is harder to palpate.

Rib Fractures and Trauma

Broken ribs are painful with every breath, cough, and shift in position. That pain is not just miserable; it causes people to breathe shallowly, which raises the risk of pneumonia and other lung complications. Intercostal nerve blocks address this directly. A study of rib fracture patients found that nerve blocks produced dramatic pain reduction immediately after the procedure compared with conventional analgesics. The catch was that relief faded over time, and researchers recommended combining the block with other pain-control methods such as patient-controlled intravenous analgesia or fentanyl patches as the block wore off.²

A randomized trial took this further by pairing the nerve block with an anti-inflammatory drug (flurbiprofen axetil) given intravenously. Patients who received both the block and the IV anti-inflammatory had lower pain scores within 30 minutes, needed far less rescue analgesia, and showed better diaphragm movement and blood oxygen levels than patients who got either treatment alone.³ The practical lesson is that intercostal blocks shine as one piece of a multimodal pain plan for trauma, not as a standalone fix.

Emergency physicians are increasingly performing these blocks at the bedside. A review of thoracic nerve blocks for rib fracture patients in the emergency department concluded that blocks such as intercostal nerve blocks can be performed safely by trained emergency physicians, provide excellent chest-wall anesthesia, and reduce the need for opioids and other medications that can cause sedation or delirium.⁴

Use After Surgery

Intercostal nerve blocks have a long track record in thoracic surgery, where incisions between or through the ribs generate intense postoperative pain. After thoracotomy, patients who received intercostal blocks used significantly less opioid for up to a week compared with patients relying solely on patient-controlled intravenous opioids.⁵ This matters because opioid side effects, including nausea, sedation, constipation, and respiratory depression, are themselves barriers to recovery.

The technique also appears in cardiac surgery. In minimally invasive coronary artery bypass procedures, a continuous intercostal nerve block delivered through an indwelling catheter lowered peak pain scores and cut the need for rescue painkillers compared to a single-shot block. Patients with the continuous catheter also spent less time in the intensive care unit.⁶ The continuous approach threads a thin catheter alongside the nerve and infuses anesthetic over hours or days, essentially solving the duration problem that limits single-shot blocks.

How Long Relief Lasts and What Extends It

A single injection of bupivacaine or ropivacaine typically provides pain relief for roughly four to eight hours, depending on the drug concentration and whether epinephrine is added to slow absorption. That window is useful for bridging acute episodes, but it is often not enough. Researchers have tried several strategies to make the block last longer.

One approach that generated enthusiasm was liposomal bupivacaine, a formulation designed to release drug slowly over days. In theory, a single injection could provide multi-day relief. In practice, a systematic review and meta-analysis of studies in patients undergoing minimally invasive thoracic surgery found that liposomal bupivacaine did not reduce opioid use or pain scores at 24 or 48 hours compared with standard bupivacaine, and hospital stays were no different.⁷ The results were disappointing, and the extra cost of the liposomal formulation is hard to justify given the lack of benefit.

Dexamethasone, a corticosteroid, has shown more promise. One study compared patients who received both intravenous and perineural dexamethasone alongside their intercostal block with patients who received only intravenous dexamethasone. The combination group had lower pain scores at multiple time points through 24 hours, used less opioid postoperatively, and maintained better lung function after video-assisted thoracic surgery.⁸ Adding dexamethasone directly around the nerve appears to extend the block’s useful life without adding significant side effects.

Risks and Complications

The most talked-about risk is pneumothorax, a partial collapse of the lung caused by the needle puncturing the pleural membrane. A study of rib fracture patients receiving intercostal nerve blocks found a pneumothorax rate of about 1.4% per individual nerve blocked, adding up to roughly 9% per patient when multiple levels were injected.⁹ That study was conducted before ultrasound guidance became routine, and the rate is expected to be lower with real-time imaging. An older, much larger series of over 4,300 patients found only four cases of symptomatic pneumothorax, and a follow-up of 200 patients with routine chest X-rays revealed one silent pneumothorax.¹⁰ The numbers suggest that while pneumothorax is not vanishingly rare, clinically significant cases requiring treatment are uncommon.

Local anesthetic toxicity is the other concern. The intercostal space has a rich blood supply, so the drug is absorbed into the bloodstream faster than from most other nerve block sites. A study measuring ropivacaine blood levels after intercostal blocks during video-assisted surgery found that absorption was rapid and produced relatively high blood concentrations, especially at doses of 100 mg or more.¹¹ When multiple levels are blocked, total dose adds up quickly. Clinicians manage this by calculating a maximum safe dose before starting and sometimes adding epinephrine to the injection to slow absorption. Symptoms of toxicity, if they occur, include ringing in the ears, metallic taste, dizziness, and in severe cases, seizures or cardiac problems.

How Intercostal Blocks Compare to Other Techniques

Several regional anesthesia options target the chest wall, and comparing them has been a busy area of research. The two most common alternatives are paravertebral blocks, which deposit anesthetic next to the spine where nerves exit, and erector spinae plane blocks, which inject it into a muscle layer in the back.

Versus Paravertebral Blocks

A systematic review and meta-analysis covering thoracic and breast surgery concluded that paravertebral blocks generally provide better pain control and lower morphine consumption than intercostal blocks.¹² A comparative trial in patients undergoing single-port thoracoscopic lung surgery found that both paravertebral and epidural blocks produced lower pain scores and less rescue analgesia than intercostal blocks in the first 24 hours, though the differences faded after that point.¹³ Paravertebral blocks also covered multiple rib levels from a single injection site, which is an advantage when pain spans many dermatomes.

That said, intercostal blocks are technically simpler, carry less risk of epidural spread or sympathetic blockade, and can be performed quickly in settings where a paravertebral block would be impractical. In a randomized study comparing paravertebral, erector spinae plane, and intercostal blocks for thoracoscopic surgery, the intercostal and paravertebral groups had similar 24-hour morphine consumption, both significantly lower than the erector spinae group.¹⁴ So the gap between the two is not always large, and the best choice often depends on the clinical context.

Versus Erector Spinae Plane Blocks

Erector spinae plane blocks have gained popularity because they are considered technically easier and farther from the lung and major vessels, reducing the risk of pneumothorax. Head-to-head comparisons with intercostal blocks have produced mixed results, and the direction of the evidence seems to depend on the surgical setting and timing.

A multicenter randomized controlled trial in patients undergoing uniportal video-assisted thoracic surgery found that the intercostal block group used substantially less morphine in the first 12 and 24 hours and needed rescue analgesia far less often than the erector spinae group.¹⁵ Another randomized trial reported the same pattern: intercostal blocks produced lower pain scores at rest and with coughing in the first eight hours, and patients in the erector spinae group needed their first dose of morphine much sooner.¹⁶

On the other hand, a study in lung cancer surgery found that the erector spinae group used less opioid over 48 hours and had lower resting pain scores than the intercostal group.¹⁷ And in a trauma setting, a randomized trial in an emergency department found that the erector spinae block produced lower pain scores at 20 minutes, 60 minutes, and at discharge compared with intercostal blocks for chest wall injuries.¹⁸ The takeaway is that neither technique is universally better; the erector spinae block may spread more broadly but less predictably, while the intercostal block delivers more targeted, often faster-onset relief at the cost of requiring multiple injections and a slightly higher procedural risk.

Pediatric Applications

One of the most consistent areas of evidence for intercostal nerve blocks in children is the Nuss procedure, a minimally invasive surgery to correct a concave breastbone. The operation involves sliding a metal bar under the sternum and flipping it to push the chest wall outward, and it is notoriously painful afterward because the bar presses against the ribs from the inside.

Multiple randomized trials have tested intercostal blocks in this population. One double-blinded trial in children found that adding ultrasound-guided intercostal blocks to standard patient-controlled analgesia cut pain scores by more than three points on a ten-point scale in the recovery room, reduced opioid use over 48 hours, and lowered the rate of side effects like nausea and itching.¹⁹ A separate prospective randomized study confirmed the pattern: children who received the blocks needed less opioid in recovery and in the first 24 hours, had fewer opioid side effects, and were discharged from the recovery unit faster.²⁰ A third study, also double-blinded and controlled, found that a single-shot intercostal block significantly reduced morphine requirements and pain scores up to six hours after surgery, with lower rates of nausea, vomiting, and urinary retention.²¹ Across these trials, no serious complications from the blocks were reported, and the reduction in opioid side effects is especially meaningful in children, where nausea and sedation can slow recovery and cause significant distress.

Chronic Pain and Nerve-Destruction Techniques

Beyond acute and postoperative settings, intercostal nerve blocks serve a role in chronic pain management. One condition where they have been studied is herpes zoster, the reactivation of the chickenpox virus that causes a painful blistering rash typically along a single nerve’s territory on the chest. A case-control study comparing intercostal nerve blocks and paravertebral blocks to standard care found that both block types significantly reduced shingles-related pain burden over 30 days and lowered the incidence of postherpetic neuralgia, the dreaded chronic pain that can follow shingles. There was no meaningful difference between the two block types.²²

When pain persists after chest surgery, a condition called post-thoracotomy pain syndrome, some patients exhaust the usual menu of medications and nerve blocks. Cryoablation is a more aggressive option: instead of temporarily numbing the nerve, a probe freezes it to destroy the pain-transmitting fibers. A retrospective study of CT-guided intercostal nerve cryoablation for post-thoracotomy pain syndrome found that about 69% of patients experienced significant improvement, with a median drop of three points on a pain scale over a median follow-up of 11 months.²³ Cryoablation during thoracotomy itself has also been studied. A prospective randomized trial applying cryoanalgesia to the intercostal nerves at the time of surgery found consistently lower pain scores and reduced opioid use throughout the first week. All patients experienced temporary numbness around the incision lasting one to six months, with full sensation returning by six months.²⁴ The trade-off is accepting months of numbness in exchange for much better pain control during the period when it matters most.

When an Intercostal Block Makes the Most Sense

Not every chest-wall pain problem calls for this particular procedure. Intercostal blocks tend to be the strongest choice when the pain is well localized to a few rib levels, when a quick onset is needed, and when the clinical setting does not support a more involved technique like a paravertebral or epidural block. In the emergency department, a few targeted injections under ultrasound can get a patient with rib fractures breathing comfortably within minutes, buying time to arrange definitive care. In the operating room, the surgeon has direct visualization of the nerves and can place the block under ideal conditions. For pain spanning many rib levels or requiring multi-day control, a paravertebral or epidural approach often makes more sense, though a continuous catheter can partially close that gap.

The procedure’s simplicity is both its greatest asset and its limitation. It does one thing well: it numbs the nerve at the level where you inject. It does not spread to adjacent levels the way a paravertebral injection can, and it does not last as long as a catheter-based technique without additional hardware. Understanding that trade-off is the key to knowing when the block is the right tool and when you need something with more reach or staying power.