Definition & Overview
Minimally invasive pectus excavatum repair, as the name suggests, is a surgical procedure used to repair a congenital chest wall deformity called pectus excavatum. Because of its shape, it is also known as sunken or funnel chest.
In pectus excavatum, the sternum and some of the ribs grow abnormally, leading to the sunken appearance of the chest wall. It is a relatively common congenital condition and is quite noticeable at birth. As the child grows older, there is the tendency for the condition to worsen leading to cardiac and pulmonary function problems that can cause breathing difficulties.
The surgical procedure was initially developed by Dr. Donald Nuss, leading to the procedure being termed as the Nuss technique. The same technique is still being used today, though some surgeons have made some small variations or modifications to fit the needs of individual patients.
Who Should Undergo and Expected Results
Not all patients diagnosed with pectus excavatum are automatically advised to undergo the surgery. Only those with severe cases are advised to take advantage of this procedure after the severity has been determined by several tests. Patients who experience impaired cardiopulmonary functions due to chest deformity are also offered this repair technique. Examples of symptoms include chest pain, shortness of breath following brief periods of inactivity, and getting tired easily. In some cases, minimally invasive pectus excavatum repair is also considered for those whose chest deformity causes psychological stress and social isolation.
When a child is born with this condition, it is usually advisable to wait for several years before they undergo this procedure. Studies found that the optimal age range for the surgery is between 8 and 12 years old, when best results are often achieved.
Though it is not typical, there are also adults who undergo this procedure, especially if their condition has found to worsen or they start exhibiting symptoms of cardiopulmonary distress.
As for the expected results, minimally invasive pectus excavatum repair has high satisfaction ratings and is considered safe with good results in short- and long-term outcome studies. Patients report improvements in their pulmonary and cardiovascular functions. The shape of their chest also showed remarkable improvement following the procedure.
How is the Procedure Performed?
Prior to the actual procedure, a template is measured for the length and shape of the stainless steel bar to be inserted into the chest cavity. The template should match the curvature of the depressed cavity and the curved steel bar should fit the chest snugly.
For the actual procedure, the patient is placed under general anaesthesia before the surgeon inserts an endotracheal tube, radial arterial line, and Foley catheter. The skin of the surgery site is marked on each side of the sternum, measuring the pectus depth at its deepest point. At this point of the depressed cavity, the surgeon makes incisions on the left and right side of the chest, on the midaxillary line.
A thoracoscope is then inserted to provide visualisation of the mediastinal structure, the lungs, and the pleural cavity. The skin incisions are elevated and a device known as the Lorenz pectus introducer is inserted into the incision at the right part of the sternum. It is then advanced across the mediastinal space and as it passes through, the sternum is also lifted. At this point, utmost care is taken not to touch any nearby organs like the heart or the lungs. When the tip of the introducer is brought out through the left incision, it grasps a strand of umbilical tape, which is tied to the mediastinal tube that is used to pull the tube through the created tunnel. The tube is then lubricated for ease of passage, gently dilating the tunnel as it is positioned under the skin of the chest cavity. A steel bar is then inserted into the tube. In some cases, the surgeon would forego the use of the mediastinal tube and would directly tie the umbilical tape to the steel bar. Once the bar is properly positioned with the convex part facing posteriorly, the mediastinal tube and umbilical tape are removed.
A specialised device called Lorenz pectus bar rotational instrument is used to turn the steel bar to make the concave part face posteriorly as the convex part is facing the sternum. In some instances wherein the curve of the bar needs to corrected, the surgeon may opt to flip it back, take it out, and bend it slightly to shape before inserting it back again into the mediastinal space. Once proper curvature is achieved, the ends of the steel bar are placed within the subcutaneous tissue, avoiding protrusion in the sides of the chest. Depending on the need, the surgeon may place one or two stabiliser bar at the ends of the steel bar using wire sutures to prevent rotation or misalignment. Several sutures are also needed to attach the implants to the chest wall muscles.
Before closing the incisions, the surgeon will perform several procedures to eliminate any residual pneumothorax.
Following the procedure, patients are advised to stay in the hospital for several days for monitoring. As pain and discomfort recede, they are allowed to go back to their normal, daily activities, though strenuous activities should be avoided. They are also advised to undergo physical therapy to promote healing. After several years, the implanted bars are removed and discarded.
Possible Risks and Complications
Undergoing any surgical procedure places the patient at risk of experiencing an adverse reaction to anaesthesia, bleeding, and possible infection of the surgical site.
Despite careful care, some patients still develop pneumothorax or the presence of air in the lung cavity and chest wall. This requires immediate medical attention. In some cases, there is build up of fluid in the lung cavity that has to be drained.
There are also reports of sterile seroma formation, characterised by a pocket of clear fluid under the skin surface.
Cahill JL, Lees GM, Robertson HT. A summary of preoperative and postoperative cardiorespiratory performance in patients undergoing pectus excavatum and carinatum repair. J Pediatr Surg. 1984 Aug. 19(4):430-3.
Hebra A, Swoveland B, Egbert M, Tagge EP, Georgeson K, Othersen HB Jr. Outcome analysis of minimally invasive repair of pectus excavatum: a review of 251 cases. J Pediatr Surg. 2000 Feb. 35(2):252-7; discussion 257-8.