Are Surgical Clips Left in After Surgery?

Surgical clips are routinely left inside the body after surgery, and in most cases, that is entirely intentional. Surgeons use small metal or polymer clips to clamp blood vessels, seal ducts, and mark tissue during a wide range of procedures, from gallbladder removal to cancer surgery. These clips are designed to stay put permanently, and for the vast majority of patients they cause no problems at all. But questions about what happens to those clips over time, whether they interfere with imaging, and whether they can migrate or cause reactions are worth understanding, especially if you are heading into a procedure or have already had one.

Why Clips Are Left Behind on Purpose

Surgical clips serve a straightforward function: they pinch blood vessels and ducts shut so that blood or other fluids do not leak after the surgeon has finished cutting. Think of them as tiny, permanent clamps. During a gallbladder removal, for example, the surgeon places clips on the cystic duct and cystic artery before severing them. Those clips need to stay in place to keep everything sealed. Removing them would defeat their purpose. The same applies in vascular surgery, lung procedures, and operations where tissue needs to be marked for future imaging.

The clips themselves are small, typically just a few millimeters long. Most are made of surgical-grade titanium, which is lightweight, strong, and produces very little reaction in human tissue. Titanium clips cause minimal inflammation and are considered extremely biocompatible.¹ Some clips are made of stainless steel or tantalum, though titanium has become the standard. Polymer-based clips, including absorbable varieties, are also available and are increasingly used in certain contexts.

What Clips Are Made Of and Why It Matters

The material of a surgical clip affects everything from how your body reacts to it, to how it shows up on a scan, to whether it might eventually dissolve. Titanium is the workhorse: it is strong enough to hold vessels closed under arterial pressure, radiopaque (meaning it shows up clearly on X-rays), and causes minimal tissue inflammation. The tradeoff is that titanium clips stay in your body permanently and can interfere with certain imaging studies.

Metal clips, including titanium ones, can cause significant interference with CT scans, and in some cases they have poor holding power or erode into surrounding structures.² This is one reason absorbable polymer clips have gained traction. These clips are designed to break down inside the body through a process called hydrolysis, typically over about seven months.³ By that point, the tissue has healed enough that the clip is no longer needed. The appeal is obvious: no permanent foreign object, and less imaging interference down the road.

Locking polymer clips, such as the Hem-o-lok, occupy a middle ground. They are non-absorbable but made of plastic rather than metal, so they do not cause the same kind of imaging artifacts. They tend to have strong holding power, especially on medium-sized vessels.⁴ However, an FDA database review identified 27 reports of Hem-o-lok clip failures, with nearly half occurring during urologic laparoscopic procedures, where bleeding was the primary concern in most cases.⁵ That number is very small relative to the millions of times these clips are used, but it underscores that no clip system is foolproof.

Are Surgical Clips Safe for MRI?

This is one of the most common worries patients have after learning they have clips inside them, and the short answer for most surgical clips is yes. The concern makes intuitive sense: an MRI machine generates a powerful magnetic field, and if a metal clip were strongly attracted to that magnet, it could theoretically move or heat up. But the standard titanium and stainless steel hemostatic clips used in general surgery have been tested and shown to be safe during MRI, even at the higher field strengths used in modern scanners.

In one study, commonly used hemostatic clips from major manufacturers were tested in an in vitro system and did not migrate or become dislodged during MRI.⁶ A more recent evaluation at 3-Tesla, which is the highest field strength commonly used in clinical imaging, confirmed that metallic surgical clips and vessel ligation clips showed only minor magnetic interactions and negligible heating, with the highest temperature change reaching just 1.6°C.⁷ Both studies concluded that patients with these implants can safely undergo MRI.

There is an important exception, though. Certain older aneurysm clips used in brain surgery are made of highly ferromagnetic materials and have been shown to move dangerously inside an MRI.⁶ This is why MRI centers always ask whether you have any implants: the concern is not about standard surgical clips but about specific devices that were manufactured from different alloys. If you know you have had brain aneurysm surgery, or you are unsure what type of clips were used, your doctor and the MRI team will need to verify compatibility before scanning you.

How Clips Affect CT Scans and Other Imaging

While MRI safety is generally not an issue, imaging artifacts from clips are a real and ongoing problem in radiology. When a surgeon leaves clips inside you and you later need a CT scan of that area, the clips can throw off the image. The severity depends on the material. A classic comparison found that tantalum clips produced severe image degradation, stainless steel clips produced moderate degradation, and titanium clips caused minimal artifacts. Absorbable polymer clips had the least effect on CT images while still remaining visible on the scan.⁸

This matters most when clips are near an area that radiologists need to examine closely, such as a tumor site being monitored for recurrence. In one study of patients who had undergone surgery for pancreatic cancer, local recurrence showed up as tissue nodules on surgical clips in about 94% of cases.⁹ Clip artifacts can make it harder to distinguish between normal post-surgical scarring and something more concerning. On the flip side, displaced clips can also mimic a growing tumor when the actual cause is just fibrosis and scar tissue pulling the clips apart over time.¹⁰

Newer imaging technology is making this less of a headache. Photon-counting CT scanners with metal artifact reduction algorithms can significantly reduce the distortion caused by surgical clips, particularly at higher energy settings.¹¹ But these advanced scanners are not available everywhere, so clip artifacts remain a practical consideration for many patients.

Absorbable Clips and Their Own Quirks

Absorbable clips were developed partly to sidestep the imaging problems that permanent clips create. Since they dissolve within several months, they should not interfere with follow-up scans. But as with most things in medicine, the solution introduces its own wrinkles.

As these clips break down by hydrolysis, their structure disintegrates and triggers a foreign body reaction. That reaction can create soft tissue nodules that look, on a scan, a lot like recurrent cancer.³ For a patient being monitored after cancer surgery, this is a genuinely stressful problem. It can lead to unnecessary biopsies or additional imaging to rule out disease that was never actually there. Radiologists have become more aware of this pitfall over time, but it remains something to discuss with your surgical team if absorbable clips are being considered and post-operative imaging surveillance is part of your care plan.

Clip Migration

Most clips stay exactly where the surgeon placed them for the rest of your life. In rare cases, though, clips can migrate from their original position, sometimes causing real problems. The most studied scenario involves clips placed during gallbladder removal (cholecystectomy), where a clip can work its way into the bile duct and act as a nidus for stone formation.

Post-cholecystectomy clip migration is uncommon but well documented. A review of 69 cases found that the median time from the original surgery to symptoms was about 26 months, though the range was enormous, spanning from as little as 11 days to as long as 20 years after the initial operation.¹² The most common presentations were jaundice, infection of the bile ducts, biliary colic, and acute pancreatitis.¹² The mechanism appears to involve inflammation and gradual tissue breakdown around the clip, eventually allowing it to erode into the bile duct.¹³

It is worth distinguishing between migration and a “dropped” clip. Migration refers to a clip that was properly placed but later shifts on its own. A dropped clip is one that was accidentally released during surgery and fell into the abdominal cavity. Dropped clips during laparoscopic cholecystectomy are not uncommon, and while most surgeons try to retrieve them, this is not always straightforward, so they are sometimes left behind.¹³ In rare instances, a dropped clip has been found at a site where it could not have been placed intentionally, confirming it was simply lost during the procedure.¹⁴ Most dropped clips are harmless, but occasionally they can serve as a focus for infection or inflammation.

Allergic Reactions to Surgical Clips

True allergic reactions to surgical clips are rare, but they do exist and can be surprisingly difficult to diagnose. Titanium is generally considered hypoallergenic, which is one reason it is so widely used. However, surgical clips may also contain nickel, and some people have a well-established nickel allergy that extends to implanted devices.

In one reported case, a patient developed symptoms after gallbladder surgery that were eventually traced to a metallic allergy to the surgical clips. All six clips were surgically removed, and the patient’s symptoms resolved substantially.¹⁵ The proposed mechanism involves metal particles released from the clips activating the immune system and sensitizing certain immune cells to the metallic allergens.¹⁵ If you have a known metal allergy, particularly to nickel, it is worth mentioning this to your surgeon before any procedure that may involve metal clips. Alternative materials or clip-free techniques may be available.

Clip-Free Alternatives

Clips are not the only way to seal blood vessels and ducts during surgery. Energy-based sealing devices, which use ultrasonic vibration or bipolar electrical current to fuse tissue shut, have become widely available. These tools seal vessels by denaturing the proteins in the vessel wall, essentially welding the tissue closed without leaving any hardware behind.

How do they compare to clips on holding power? In experimental studies, clips generally provided higher burst pressures than thermal sealing devices on small and medium vessels. But as vessel size increased to the 4-5 mm range, advanced bipolar devices began to match the strength of ligation clips.⁴ Another comparison found that bipolar vessel sealers showed lower burst pressures in arteries compared to other methods, and plastic clips showed lower pressures in veins, suggesting that the best approach may depend on the specific vessel being sealed.¹⁶

Suture ligation, the old-fashioned approach of tying off a vessel with thread, is another clip-free option that remains the gold standard for very large vessels and situations where security is paramount. In practice, most surgeons choose the method best suited to the specific tissue and vessel they are dealing with. For many procedures, clips remain the fastest and most reliable option, which is why they continue to be so widely used.

Breast Biopsy Clips

Surgical clips used to mark a biopsy site in the breast are a slightly different category from the hemostatic clips discussed above, but patients often have the same questions about them. After a breast biopsy, a tiny marker clip is placed at the biopsy site so that the area can be found again on future imaging. These clips are permanent and generally cause no issues, but immediate migration of the clip from its intended location is a recognized concern.

A meta-analysis of breast biopsy clip migration found that the most significant risk factor for the clip moving from where it was placed is having a breast composed mostly of fatty tissue, which roughly doubled the risk of immediate migration. Local tissue density around the clip site and the use of bioabsorbable carrier materials did not significantly change migration rates.¹⁷ When a clip migrates far from the biopsy site, it can make it harder to relocate a suspicious area later, potentially leading to additional procedures. This is one reason your radiologist may take a follow-up image immediately after placing the clip to confirm it is in the right spot.

How Clip Size and Weight Influence Tissue Reactions

Not all clips provoke the same degree of tissue response, and the differences come down to more than just what the clip is made of. The physical size and weight of the clip matter. Smaller titanium stapler clips consistently produce less inflammation and fewer adhesions than larger devices. DS clips, which are a single-piece design used in some appendectomy procedures, weigh about two and a half times more than standard stapler clips, and that extra bulk correlates with a stronger inflammatory response and more adhesion formation.¹

Adhesions are bands of scar tissue that form between internal organs and the abdominal wall, and they can cause pain, bowel obstruction, or complications in future surgeries. While any abdominal surgery carries some adhesion risk, minimizing the amount of foreign material left behind is one lever surgeons can pull to reduce it. This is part of the broader trend toward less invasive techniques, smaller instruments, and, where appropriate, absorbable or clip-free approaches.

Regulatory Monitoring of Clip Problems

In the United States, the FDA tracks post-market safety data on medical devices, including surgical clips, through its MAUDE (Manufacturer and User Facility Device Experience) database. When a clip fails, migrates, or causes an unexpected adverse event, hospitals and manufacturers are required to file reports. Researchers periodically analyze these databases to spot patterns that might not show up in clinical trials.

Studies of both over-the-scope clips used in gastrointestinal procedures and newer anchor-prong clips have drawn on MAUDE data to characterize the range of problems that occur in real-world use.¹⁸¹⁹ The existence of this surveillance system means that clip-related complications are tracked and analyzed even after a product has been cleared for sale, which is a layer of safety that was not always available for older devices. If you are curious about the safety record of a specific clip type, these reports are publicly searchable on the FDA’s website, though the data can be technical and is better interpreted with your surgeon’s guidance.

What to Ask Your Surgeon

If you are going into a procedure that may involve surgical clips, a few practical questions can put you at ease and help avoid issues down the road. Ask whether clips will be used and what material they are made of, especially if you have a known metal allergy. Ask whether absorbable or clip-free alternatives are appropriate for your specific situation. Find out whether the clips will show up on future imaging and whether they could affect the interpretation of follow-up scans, particularly if you are being monitored for cancer recurrence.

After surgery, make sure the presence of clips is noted in your medical record. If you ever need an MRI, knowing what kind of clips you have and where they are located will help the imaging team confirm that scanning you is safe. For the vast majority of patients, the clips will sit quietly inside you for decades without you ever knowing they are there. The rare complications, whether migration, allergic reactions, or imaging interference, tend to announce themselves with symptoms that your doctor can evaluate in the context of your surgical history.

1
PubMed Central. Tissue Reaction and the Formation of Adhesion after the Use of DS Clip in Laparoscopic Appendectomy – Section: Discussion
2
PubMed. Comparison of titanium and absorbable polymeric surgical clips for use in laparoscopic cholecystectomy
3
Clinical Radiology. Absorbable laparoscopic ligating clips: Impact on postoperative CT imaging
4
PubMed. Comparison of ultrasonic energy, bipolar thermal energy, and vascular clips for the hemostasis of small-, medium-, and large-sized arteries – Section: Results
5
PubMed. Reported failures of the polymer self-locking (Hem-o-lok) clip: review of data from the Food and Drug Administration – Section: RESULTS
6
PubMed. Safety of metallic surgical clips in patients undergoing high-field-strength magnetic resonance imaging
7
PubMed Central. Assessment of MRI issues at 3-Tesla for metallic surgical implants: findings applied to 61 additional skin closure staples and vessel ligation clips
8
PubMed. Surgical ligation clip artifacts on CT scans
9
PubMed. CT imaging of early local recurrence of pancreatic adenocarcinoma following pancreaticoduodenectomy – Section: RESULTS
10
PubMed. Metallic clip displacement in evaluating tumor recurrence or enlargement: a source of error
11
European Journal of Radiology. Metal artifact reduction from surgical clips for intracranial aneurysms in photon-counting detector CT angiography – Section: Discussion
12
Journal of Gastrointestinal Surgery. Biliary Complications Secondary to Post-Cholecystectomy Clip Migration: A Review of 69 Cases
13
PubMed. An unusual complication of a dropped clip during laparoscopic cholecystectomy
14
European Journal of Radiology. Sepsis from dropped clips at laparoscopic cholecystectomy – Section: Methods and materials
15
PubMed Central. Rare Metallic Allergy Reaction Presentation to Cholecystectomy Surgical Clip
16
PubMed. Comparison of various methods of vessel ligation: what is the safest method? – Section: RESULTS
17
The British Journal of Radiology. Immediate clip migration after breast biopsy: a meta-analysis for potential risk factors
18
Techniques and Innovations in Gastrointestinal Endoscopy. Analysis of Reported Adverse Events Related to Over-the-Scope Clips: A MAUDE Database Analysis
19
PubMed. Reported adverse events of the anchor prong clip: a MAUDE database analysis – Section: METHODS