Nuss procedure in adult pectus excavatum: a simple artifice to reduce sternal tension

Stiffness reduction of the rib cage to perform a minimally invasive pectus excavatum repair: biomechanical evaluation

OBJECTIVES

To study the influence of sternal transection and costal chondrotomies on the stiffness and stresses in the rib cage of adult patients undergoing Nuss pectus excavatum procedure.

METHODS

Four pectus excavatum models with different Haller indexes were created by parameterizing a 3D model of a rib cage obtained based on a computed tomography scan of a patient with no pectus deformity. Using the finite element method, insertion of intrathoracic bars into all models was simulated in 3 conditions, namely, non-intervened, transverse sternal section and costal chondrotomies. Stiffness, stress distribution and maximum stresses for each case were obtained and compared.

RESULTS

Transverse sternotomy provided a reduction of 44% to 54% in the stiffness of the rib cage, depending on the Haller index analysed, while chondrotomies promoted a stiffness reduction of 70%. Stress distribution in the rib cage followed similar pattern for all the tested Haller index, but the maximum stress decreased by 36% when performing a transverse sternotomy, whereas when performing costal chondrotomies, it decreased by 47%.

CONCLUSIONS

Computational results report that transverse sternotomy reduces appreciably the stiffness of the rib cage, while costal chondrotomies promote even a higher stiffness reduction. Thus, these surgical procedures could improve the clinical outcomes of adult patients undergoing a pectus excavatum repair.

Pectus excavatum and scoliosis: a review about the patient's surgical management

Although Nuss procedure is performed with satisfactory results, there has been a controversy in the literature regarding the effect of a Nuss procedure on the spine. This review article aims to perform an updated overview of the literature about the effect of pectus excavatum correction at the spine and the management of patients with both pectus excavatum and scoliosis. Although acquired scoliosis has been rarely reported after a Nuss procedure, studies show that the Nuss procedure can have a beneficial effect in mild coexisting scoliosis especially when it is performed during the adolescence. The management of cases presented with both pectus excavatum and scoliosis depends on the severity of pre-operative scoliosis and demands detailed evaluation of the spine pre and postoperatively. In the rare condition of post-operative scoliosis following a Nuss procedure, the removal of the metallic bar and conservative measures may have satisfactory results on the spine.

The use of nonthoracoscopic Nuss procedure for the correction of pectus excavatum by trans-esophageal echocardiography monitoring

This study was aimed to review the current experience regarding the correction of pectus excavatum by Nuss procedure with nonthoracoscopic assistance using trans-esophageal echocardiography monitoring.A total of 172 patients with pectus excavatum were surgically treated from August 2011 to August 2016. The sample size comprised 131 boys and 41 girls and the average age was 13 years and 2 months. A total of 144 cases were initially operated on, whereas 13 subjects exhibited postoperative recurrence following Ravitch repair of a pectus excavatum deformity and 15 cases experienced a history of median sternotomy. The intraoperative Haller index ranged from 3.6 to 14.2 (mean 4.1). The intraoperative TEE monitoring was conducted with middle-esophageal 4-champer view and middle-esophageal Aortic short axis view to detect the injury of heart and of the large vessels by the introducer and Nuss steel bars.The operation conducted in all patients was successful in the absence of severe complications. The time of operation ranged from 38 to 80 minutes (mean 50 minutes). The bleeding volume during the procedure was between 10 and 40 mL (mean 15 mL). The time from operation to discharge was from 5 to 7 days (mean 6 days). Pneumothorax occurred in 25 cases following the termination of the operation, including 9 cases of needle puncture aspiration and 6 cases of closed drainage. Pleural effusion occurred in 4 cases. No patients suffered from wood infection. Effusion occurred in 9 cases following 6 to 23 months, whereas dressing changes and surgical debridement were evident in 2 and 7 cases, respectively. The bars were removed in 82 of the 172 patients within 3 years. The progression of the thoracic wall was assessed for the period of 8 to 68 months following the surgery, during the follow-up period. The average time period of follow-up was 32 months.Nuss procedure with nonthoracoscopic assistance with trans-esophageal echocardiography monitoring for the correction of pectus excavatum was safe for all of the cases investigated. It exhibited lesser trauma and required a shorter time period.

Nuss procedure in the adult population for correction of pectus excavatum

Minimally invasive repair of pectus excavatum has been successfully modified for use in adult patients. Many patients present in adulthood with progression of symptoms as the chest wall becomes less compliant with age. A thorough workup is completed including echocardiogram and chest CT to evaluate for anatomic abnormalities. Cardiopulmonary exercise testing is done to quantify the physiologic impact. Modifications of the original Nuss procedure required to allow for successful adult repair include the use of forced sternal elevation, the use of multiple bars, medial bar fixation, and interspace support to prevent bar rotation and migration. Occasionally, fractures may occur that require an open procedure and osteotomy or cartilage resection and hybrid approach incorporating the principals of intrathoracic support and osteotomy with bar stabilization.

Outcomes in adult pectus excavatum patients undergoing Nuss repair

Pectus excavatum (PEx) is one of the most common congenital chest wall deformities. Depending on the severity, presentation of PEx may range from minor cosmetic issues to disabling cardiopulmonary symptoms. The effect of PEx on adult patients has not been extensively studied. Symptoms may not occur until the patient ages, and they may worsen over the years. More recent publications have implied that PEx may have significant cardiopulmonary implications and repair is of medical benefit. Adults presenting for PEx repair can undergo a successful repair with a minimally invasive "Nuss" approach. Resolution of symptoms, improved quality of life, and satisfying results are reported.