Correcting mediastinum left displacement improves the imbalance in the pulmonary vascular bed and lung volume in children with pectus excavatum after the Nuss procedure

  • Dr Shinya Shimoyama, Department of Pediatrics, Gunma University Graduate School of Medicine, Gunma, Japan / Maebashi Saiseikai Hospital, Japan, Japan
  • Dr Tohru Kobayashi, Department of Pediatrics, Gunma University Graduate School of Medicine, Maebashi, Gunma, Japan, Japan
  • Dr Hiroyuki Mochizuki, Department of Pediatrics, Gunma University Graduate School of Medicine, Maebashi, Gunma, Japan, Japan
  • Dr Akito Hamajima, Department of Plastic and Reconstructive Surgery, Gunma Children’s Medical Center, Shibukawa, Gunma, Japan, Japan
  • Dr Tomio Kobayashi, Department of Cardiology, Gunma Children’s Medical Center, Shibukawa, Gunma, Japan, Japan
  • Dr Shinitu Hatakeyama, Department of Radiology, Gunma Children’s Medical Center, Shibukawa, Gunma, Japan, Japan
  • Prof Hirokazu Arakawa, Department of Pediatrics, Gunma University Graduate School of Medicine, Maebashi, Gunma, Japan, Japan

    • Objectives: The imbalance of pulmonary perfusion and lung volume in patients with pectus excavatum (PE) after the Nuss procedure has not been objectively assessed. The study sought to assess the degree of impairment of the cardiovascular system in patients with PE and to investigate any changes caused by surgical correction. Methods: Chest radiography, computed tomography (CT) and pulmonary perfusion scintigraphy were performed before surgery and at medium-term follow-up (2.7±0.3 years) in 34 patients operated on for PE. Chest radiography was used to calculate the vertebral index (VI) and the left displacement index (LDI), which is the ratio between the left border of the mediastinum and the left border of the thorax to the transverse thoracic dimension on posterioanterior chest radiography. Left-to-right count ratio for lung scintigraphy (Ls/Rs), and the left-to-right thorax volume ratio from CT (Lv/Rv) were also measured. Results: Preoperative left pulmonary perfusion and lung volume were significantly impaired compared with the right lung. After the Nuss procedure, Ls/Rs and Lv/Rv were significantly increased (Ls/Rs; 0.81±0.09 vs. 0.89±0.09, P=0.001: Lv/Rv; 0.68±0.08 vs. 0.79±0.08, P<0.001). LDI correlated with Ls/Rs (R=0.510, P<0.001) and Lv/Rv (R=0.769, P<0.001); there was no correlation for VI with Ls/Rs. Conclusions: Our findings indicated that the imbalance of pulmonary perfusion and lung volume improves in PE patients after completion of the Nuss procedure. The alternations might be related to the improvement from the left shift of the mediastinum.