European Journal of Cardio-Thoracic Surgery 59 (2021) 375–381 ORIGINAL ARTICLE doi:10.1093/ejcts/ezaa328 Advance Access publication 30 October 2020 Cite this article as: Is¸can_ M, Kılıc¸ B, Turna A, Kaynak MK. The effect of minimally invasive pectus excavatum repair on thoracic scoliosis. Eur J Cardiothorac Surg 2021;59:375–81. The effect of minimally invasive pectus excavatum repair on thoracic scoliosis Mehlika Is¸can_ a,*, Burcu Kılıc¸b, Akif Turna b and Mehmet Kamil Kaynak b a Department of Thoracic Surgery, Gebze Fatih State Hospital, Kocaeli, Turkey b Department of Thoracic Surgery, Istanbul University-Cerrahpas¸a,Cerrahpas¸aSchool of Medicine, Istanbul, Turkey Downloaded from https://academic.oup.com/ejcts/article/59/2/375/5943430 by guest on 29 September 2021 * Corresponding author. Department of Thoracic Surgery, Gebze Fatih State Hospital, 41400 Gebze - Kocaeli, Turkey. Tel: +90-543-6609334; e-mail: [email protected] (M. Is¸can)._ Received 13 March 2020; received in revised form 17 July 2020; accepted 23 July 2020 THORACIC Abstract OBJECTIVES: The Nuss technique comprises the placement of an intrathoracic bar behind the sternum. However, besides improving the body posture through the correction of the pectus excavatum (PE), this procedure may cause or worsen thoracic scoliosis as a result of the considerable stress loaded on the chest wall and the thorax. Our goal was to investigate the impact of the Nuss procedure on the thoracic spinal curvature in patients with PE. METHODS: A total of 100 patients with PE who underwent the Nuss procedure were included in the study and evaluated retrospectively. The Haller index (HI), asymmetry index and sternal torsion angle were calculated from thoracic computed tomography images before the operation. To evaluate the scoliosis in the T2–T8 thoracic vertebrae, Cobb angles were calculated on a plain chest X-ray before the Nuss operation and after the removal of the bar. Cobb angles were classified as normal (5), scoliotic posture (5–10) and scoliosis (>10). All angles before and after the Nuss operation were compared. The patients were followed up for a mean of 41 months. Substernal bars were removed after a mean of 33 months. VC The Author(s) 2020. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved. 376 M. Is¸can_ et al. / European Journal of Cardio-Thoracic Surgery RESULTS: The mean age of the patients was 19.6 ± 6.7 years. The Cobb angle was statistically significantly increased in all patients (P = 0.01), male patients (P = 0.01) and children (P = 0.046) but not in adults (P = 0.11) and female patients (P = 0.54). The Cobb angle was increased in patients with severe (HI >_ 3.5) but not in patients with moderate (3.2 < HI < 3.5) or mild (2.0 < HI < 3.2) PE deformity. CONCLUSIONS: The present study shows that the Cobb angle indicates that the severity of thoracic scoliosis increases following the Nuss procedure, particularly in male patients, in patients with mild and moderate sternal torsion angle and in those with a high preoperative HI. This alteration might be due to correctional forces and torque applied by the bar. Patients undergoing the Nuss procedure for the correc- tion of PE should be followed up strictly for timely diagnosis and management of the scoliosis. Keywords: Nuss procedure • Pectus excavatum • Haller index • Scoliosis • Cobb angle study was to investigate the impact of the Nuss procedure on ABBREVIATIONS thoracic spinal curvature in patients with PE and to assess whether it was associated with scoliosis. Downloaded from https://academic.oup.com/ejcts/article/59/2/375/5943430 by guest on 29 September 2021 AI Asymmetry index BMI Body mass index HI Haller index MATERIALS AND METHODS PE Pectus excavatum STA Sternal torsion angle Patient selection All patients who underwent the minimally invasive Nuss proced- INTRODUCTION ure, later interventions (removal of the intrathoracic bar) and follow-up studies at our tertiary care university clinic between Pectus excavatum (PE) is a common congenital chest anomaly July 2011 and July 2015 were enrolled in this retrospective ana- with an incidence of 1 in 1000 live births and a male-to-female lysis. All study participants provided informed consent. The need ratio of 3-to-1 [1]. It is a musculoskeletal malformation resulting for institutional review board approval was waived according to from inadequate fusion between the costae and sternum during our country’s law because the study is a retrospective cohort embryologic development leading to the depression of the anter- study. Data concerning the demographic characteristics of ior chest wall [2]. Although the malformation itself seldom causes patients and their physical examination and their posterior–an- problems and most subjects are asymptomatic, the inward de- terior chest X-ray and thorax computed tomography results were formation may affect organs enclosed within the thoracic space retrieved from patient charts and the institutional digital data- and has been shown to result in various problems, including re- base. Offline measurements of the preoperative Haller index (HI), strictive pulmonary deficits, right-sided heart compression, mitral asymmetry index (AI) and the sternal torsion angle (STA) were valve prolapse and dysrhythmias. Furthermore, those with PE performed using the computed tomography images of the thorax may also experience exercise intolerance and dyspnoea on exer- for each patient. Cobb angles were calculated from a plain chest tion in the presence of compression on the right ventricular out- X-ray. The Cobb angle measurement was repeated following the flow [3]. removal of the intrathoracic bar (Fig. 1). Measurement of the Conservative management of PE mainly focuses on the reduc- Cob angle was performed by an experienced orthopaedist tion of pain, which is the presenting complaint in many symp- blinded to patient data. tomatic patients. Anti-inflammatory agents, acupuncture, physical therapy and osteopathic manipulative treatments have The Nuss procedure long been used in the management of pain [4]. A device known as the vacuum bell, which applies suction to the chest wall, may The indications for the operation that we used in the current also be used in younger patients [5]. However, surgical correction study are as follows: is recommended for subjects with a Haller score >3.25 or a cor- rection index score of >20% [6]. The optimal time for correction • Progressive and symptomatic PE, is currently accepted as mid-adolescence, because subjects • Restrictive breathing pattern, measured by pulmonary func- undergoing repair during this stage may complete their growth tion tests, with a low risk of recurrence [7, 8]. Nevertheless, successful repair • Cardiac compression, pulmonary atelectasis, of PE with low morbidity and considerable improvement in • Heart disorders with mitral valve prolapse or branch block, physiological function has also been demonstrated in the adult • HI index greater than 3.25, population [9]. • Psychosocial indications. Two decades ago, Nuss et al.[10] developed a procedure that has come to be known as the Nuss technique; it comprises the If the patient who was being considered for an operation had placement of a bar behind the sternum. However, although this an HI <3.25 and greater than 2.5 and had other indications, we technique improves body posture through the correction of the performed the operation. PE, it may also cause or worsen thoracic scoliosis as a result of The procedure was performed with the patient under general the considerable stress loaded on the chest wall and the thorax anaesthesia. Lateral incisions were performed on both sides of [11, 12]. the chest to insert the bar, which was curved according to indi- Data are limited concerning the effects sustained by the thor- vidual characteristics and requirements. The bar was initially acic spine after the correction of PE. The goal of the present inserted in line with the curvature of the sternum and M. Is¸can_ et al. / European Journal of Cardio-Thoracic Surgery 377 Downloaded from https://academic.oup.com/ejcts/article/59/2/375/5943430 by guest on 29 September 2021 Figure 2: Haller index = a/b. Figure 1: Cobb angle measurement. THORACIC placement was performed under the guidance of a thoraco- scope. When the bar was in the target position behind the ster- Figure 3: Asymmetry index = c/d. num, it was flipped 180 so that the curvature would elevate thedepression.Followingthefixationofthebarstotheribs,the primary closure of the incision was performed. A steel plate was used to facilitate the fixation of the bar to the ribs. Following a The STA was measured from evaluations of the axial plane and was defined as the angle of the axis of the mediolateral length to median treatment time of 33 (20–60) months, the bar was removed. Our policy was to leave the bar in place for 2 years. the horizontal length. An STA value higher than 30 indicates se- Patients were called for removal at 2 years. However, some vere torsion of the sternum (Fig. 4)[16]. The Cobb angle was patients did not return for removal for as long as 60 months. used to quantify the magnitude of the scoliosis. We located the We followed all patients for at least 2 years after the Nuss oper- apex, which is at the deepest part of the scoliosis curve, and then ation. The bars were removed as early as 20months after the determined the most-tilted vertebrae above and below the apex. operation for reasons related to the patients’ educational activ- The angle between the 2 lines extending from the most-tilted ities (i.e. patients tend to be admitted to the hospital during the vertebrae above the apex and the most-tilted vertebra below the apex was determined as the Cobb angle [17] (Fig.