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Double Crush to the Thorax: Kyphoscoliosis and Pectus Excavatum

Saturday, October 20, 2012: 2:59 PM
Melrose (Hilton Riverside)
Elizabeth A. Berdan, M.D.1, A. Noelle Larson, M.D.2, Donavon J. Hess, M.D., Ph.D.3, Robert D. Acton3, Charles Gerald T. Ledonio, M.D.4, F. Glen Seidel, M.D.5, David W. Polly, M.D.4 and Daniel A. Saltzman, M.D., Ph.D.3, (1)Surgery, University of Minnesota, Minneapolis, MN, (2)Department of Orthopaedic Surgery, Mayo Clinic, Rochester, MN, (3)Department of Surgery, Division of Pediatric Surgery, University of Minnesota, Minneapolis, MN, (4)Department of Orthopaedic Surgery, University of Minnesota, Minneapolis, MN, (5)Department of Pediatric Radiology, University of Minnesota, Minneapolis, MN

Case Report

This is a 12 year old female with Arthrogryposis, congenital short stature, neurologic delay and tracheostomy dependence until the age of 3 years for thoracic dystrophy. She also has severe kyphoscoliosis and clinically profound pectus excavatum. She suffered from the double crush to the thorax with both thoracic deformities (kyphoscoliosis and pectus excavatum) requiring surgical correction. Despite these limitations, she was a very active child that fully participated in her activities of daily living without reports of cardiopulmonary insufficiency.

Currently there is no precedence for which thoracic deformity is corrected first (kyphoscoliosis or pectus excavatum). She underwent posterior spinal fusion (PSF) from T3 - L3 with Smith-Peterson osteotomies. As a result, she sustained an acute decrease in her mediastinal volume causing compression of her right heart. The decreased mediastinal volume is verified by measurement of her Haller index (HI). The HI is used to define the severity of pectus excavatum, which is the ratio between the horizontal distance of the ribcage and the shortest distance between the vertebrae and sternum (Figure 1.; Normal = 2.5; HI ≥ 3.2 Clinically Significant). Her HI acutely changed from 1.9 prior to correction of her kyphoscoliosis (Figure 1) to 3.2 after surgical correction (Figure 2). Following her PSF she was unable to ascend a flight of stairs without tachycardia and shortness of breath. These symptoms resolved after repair of her pectus excavatum.

Discussion:

The association between anterior chest wall deformities and scoliosis has frequently been mentioned but has not been vigorously studied. The close relationship between the development of the lung, diaphragm, thoracic cage and thoracic spine suggests that deformities of the thoracic spine and chest wall may be linked. The combination of deformities may have more significant thoracic volume impairment than any of the three in isolation. Correction of her kyphoscoliosis resulted in an acute increase in her HI and subsequent cardiopulmonary symptoms due to the compression of the sternum on the right ventricle. During physical exertion the heart is unable to increase cardiac output (CO = SV HR) by increasing stroke volume due to the restricted right ventricle. Therefore, the heart rate is elevated resulting in shortness of breath, fatigue and tachycardia. In this patient, her kyphosis appeared to be protective to the mediastinal crush. Once the kyphosis was repaired her physically apparent pectus excavatum became clinically significant.

There are no studies that address the operative approach when treating patients with a double crush to the thorax from the anterior intrusion of the spine and posterior intrusion of the sternum. In this patient, the surgical correction of kyphoscoliosis resulted in acute cardiopulmonary symptoms due to the acute decrease of her mediastinal volume and compression of her heart.

Figure 1.

Figure 2.