The Nuss procedure is a minimally invasive surgery that corrects pectus excavatum, a condition where the breastbone (sternum) is sunken inward toward the spine. A curved metal bar is inserted behind the sternum and flipped into position to push the chest wall outward into a normal shape. First published by Dr. Donald Nuss in 1998, it has become the most commonly used technique for repairing this condition.
How the Surgery Works
The basic concept is surprisingly straightforward. A surgeon makes small incisions on each side of the chest, then guides a curved metal bar through the chest cavity and behind the sternum. The bar enters in a U-shape, concave side up. Once in position, the surgeon rotates the bar 180 degrees using a specialized tool, which flips the curve so it pushes the sternum outward. If the chest indentation is very deep, two rotators may be used simultaneously to prevent the bar from twisting unevenly.
Before inserting the bar, the surgeon uses a camera (thoracoscope) to see inside the chest and creates a pathway under the sternum. This dissection is performed during a brief pause in breathing and typically takes less than a minute. The entry point on each side of the chest is placed just inside the highest point of the deformity, and the bar is positioned to support the deepest part of the indentation, running straight across the chest. In some cases, particularly severe deformities require two or three bars.
If the chest wall is stiff, the surgeon may hold the sternum in an elevated position for one to two minutes before rotating the bar, which helps the cartilage and bone adjust to the new shape. Once the bar is in the correct position, it’s secured to the ribs to prevent it from shifting.
Who Is a Candidate
Surgery is generally considered when a CT scan shows a Haller index of 3.25 or higher. The Haller index is a simple ratio calculated from a chest CT: the width of the chest divided by the distance between the sternum and spine at the narrowest point. A normal chest has a Haller index around 2.5, so 3.25 represents a significant inward displacement.
The ideal age for the Nuss procedure is between 12 and 18 years. During this window, the chest wall is still flexible enough to reshape without excessive force, which means less pain and fewer complications. Operating on patients over 20 is possible but more difficult because the sternum becomes harder to bend with age. Younger children are sometimes treated as well, though surgeons generally prefer to wait until the growth spurt years when the chest has reached closer to its adult dimensions.
One often-overlooked part of preparation is metal allergy testing. Since the bar sits inside the body for years, patients are patch-tested for reactions to metals before surgery. If someone tests positive for a component of stainless steel, or has a history of metal allergies or atopic conditions combined with any positive patch test result, a titanium bar is used instead.
What Recovery Looks Like
Pain management has historically been the biggest challenge with this surgery. The bar presses against the ribs and sternum constantly, and the intercostal nerves (which run along each rib) transmit significant pain signals in the early days. Traditionally, patients spent about a week in the hospital with epidural anesthesia, followed by several weeks of opioid painkillers after discharge. The average hospital stay across large studies is about five to seven days.
Newer pain management techniques are changing that timeline dramatically. Some surgical centers now freeze the intercostal nerves during the operation, a technique called cryoablation, which temporarily blocks pain signals from the surgical area. Combined with nerve blocks and a regimen of non-opioid pain medications started before surgery, this approach has cut hospital stays to roughly three days at centers using the full protocol. At Cleveland Clinic, where the technique has been refined further, some younger patients have been discharged the day after surgery, with several needing no opioid painkillers at all during their hospital stay. Those who did need them were able to stop after a single day. The nerve-freezing step adds about an hour to the operating time but significantly reduces suffering during recovery.
After discharge, you should expect soreness and limited chest mobility for several weeks. Contact sports are off-limits for at least one month to avoid dislodging the bar, but most other daily activities can resume fairly quickly. The transition back to full activity is gradual, guided by how the chest feels.
How Long the Bar Stays In
The metal bar is not permanent. It stays in place for two to three years while the chest wall remodels around its new shape. During this time, the cartilage connecting the ribs to the sternum gradually adapts to the corrected position. After that remodeling period, the bar is removed in a separate, shorter surgery.
Leaving the bar in longer than three years is generally avoided because tissue can grow around it, making removal more complex. Case reports of bars left in place for a decade describe significantly more difficult extraction procedures, reinforcing the standard two-to-three-year window.
Potential Complications
The most common serious complication is bar displacement, where the bar shifts from its intended position. This happens in roughly 2% to 17% of cases across different studies, a wide range that reflects differences in surgical technique, bar stabilization methods, and patient activity levels. Not every displacement requires a second operation. Minor shifts may not affect the correction, but more significant movement, where the bar clearly loses its supportive position, typically does require reoperation. In one study tracking displacement cases, about 8% of patients with notable bar shifts needed repeat surgery.
Other possible complications include fluid or air accumulation around the lungs, infection at the incision sites, and allergic reactions to the bar metal (which preoperative patch testing aims to prevent). Serious complications like heart or lung injury during bar insertion are rare, largely because thoracoscopic guidance lets the surgeon see the bar’s path in real time.