Force required to elevate the sternum of pectus excavatum patients.

Abstract

Pectus excavatum (PE) is one of the most common surgically correctable major congenital malformations, occurring in approximately 1 in every 400 births. Although operative procedures to correct PE deformities have been available for more than five decades, the techniques have varied greatly, as have the number of complications and the longterm results. Despite the frequency of PE, the number of patients undergoing repair was small until 1997, when the technique of minimally invasive repair of PE (MIRPE) was first reported by Nuss and associates. Variations of the modified Ravitch repair, which had been used widely by most surgeons before 1997, include subperichondrial resection of deformed costal cartilages; transverse wedge sternal osteotomy; and anterior fixation of the sternum with a variety of temporary internal support struts, prostheses, or an external harness. The MIRPE avoids cartilage resection and sternal osteotomy by placing a convex steel bar under the sternum through bilateral thoracic incisions and then forcefully turning the bar over to elevate the deformed sternum and costal cartilages to the desired position. The bar is left in place for 2 to 4 years, depending on the age of the patient and the severity of the deformity. The initial reports of favorable clinical experience with the MIRPE included primarily young children (mean age approximately 5 years). During the ensuing years, the MIRPE has been extended to older patients, including occasional adults. Although there has been initial great enthusiasm from both patients and surgeons for the MIRPE, some recent reports have indicated that although the operating time is shorter with the MIRPE than with the modified Ravitch repair, the complication rate, length of hospitalization, and severity of postoperative pain might be considerably higher with the MIRPE. The majority of patients undergoing MIRPE receive epidural analgesia for a few days and oral analgesic medications for several weeks. A major complication of the MIRPE has been flipping of the substernal bar onto the heart, which has been presumed to be related to the weight of the sternum in older patients pushing downward on the bar. The force necessary to elevate the deformed costal cartilages and sternum of PE patients to the desired level has not been previously reported. The relationship between the severity and duration of pain associated with the MIRPE and the force necessary to elevate the anterior chest to the desired level is unclear. Occasional patients have experienced such severe persistent pain after the MIRPE that they have requested early removal of the convex bar. The present study was undertaken to measure the force necessary to elevate the sternum of PE patients of varying ages and severity to the desired position. Consent for the study was granted by the Medical Center Institutional Review Board.