Ju Mei, Guoqing Li, Zhaolei Jiang, Fangbao Ding Efficacy and Safety of Novel Modified Nuss Procedure for Pectus Excavatum with A New Steel Bar Department of Cardiothoracic Surgery, Xinhua Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China Ju Mei, Guoqing Li, Zhaolei Jiang, Fangbao Ding

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Backgroud Nuss procedure is considered the most popular minimally invasive technique for the correction of pectus excavatum However, the installation and removal of steel bar sometimes is difficult and traumatic in Nuss procedure To simplify the procedure and decrease the difficulty and trauma, we designed a new steel bar and applied it in minimally invasive surgical correction for pectus excavatum The aim of this study is to examine the efficacy and safety of this novel modified Nuss procedure for pectus excavatum with the new steel bar.

Bar Configuration One end of the steel bar is fused with bar stabilizer, and the other end is designed to connect with the introducer or stabilizer The steel bars are divided into large and small sizes according to different lengths, thicknesses, and widths. The small size is used for children, and the large size is used for adolescents or adults The steel bars have 15 different specifications, which are distinguished by the different lengths, which variy from 12 to 26 cm A stainless steel bar was curved according to the normal structure of the human anteriorchest wall One end of the steel bar was fused with bar stabilizer, and the other end was designed to connect with the introducer or stabilizer The steel bars were divided into large and small sizes according to different lengths, thicknesses, and widths The small size was used for children, and the large size was used for adolescents or adults The steel bars had 15 different specifications, which were distinguis-hed by the different lengths, which varied from 12 to 26 cm Each specification had a difference of 1 cm

Bar Accessories Bar accessories include the introducer, stabilizer, and gasket The introducer and stabilizer are of different sizes to match the bars of different sizes Bar accessories include the introducer, stabilizer, and gasket The introducer and stabilizer are of different sizes to match the bars of different sizes The gaskets include: thickening gasket & lengthening gasket Thickening gasket: adjust the height of the lowest point of the sternum Lengthening gasket: improve the length of contact surface for stabiliz-er and ribs

Technique The distance between the bilateral anterior axillary lines of the intercostal level corresponding to the lowest point of the sternum is measured intraoperatively The length of the bar is 2 to 3 cm longer than the distance A 5mm diameter thoracoscope is used to guide the procedure Bilateral vertical skin incisions about 1.5 to 2.5 cm are made near the middle axillary line

Technique After the bar is tied to the end of the introducer, the introducer is inserted into the right thoracic cavity The bar is pushed in and pulled out through the tunnel after the introducer without turning it over, and the deformity is corrected After the introducer is removed, a stabilizer is placed on the left side of the bar to support and fix the bar

Preoperative & Postoperative CT Preoperative & postoperative Computed Tomography

Bar removal After the surgery, the bar is removed between 1.5 and 4 years depending on growth In children or adolescents, the bar was removed about 2 years after the operation. However, the bar should be kept for a longer time (3–4 years) in patients with recurrent pectus excavatum or in adult patients.

Clinical Experience----Patients From July 2010 to July 2011, 147 patients with pectus excavatum underwent this novel modified Nuss procedure 118 male and 29 female Age: 3-35 years (mean, 10.35±6.72 years; median, 9 years) Haller index: 3.38 – 15.23 (mean, 4.83±1.41; median, 4.52) Symmetrical pectus excavatum 102 cases Asymmetrical pectus excavatum 35 cases Recurrent pectus excavatum 10 cases

Clinical Experience----Early results The novel modified Nuss procedure was successfully performed in all patients 1 bar was placed in 144 cases (98.0%) 2 bars were placed in 3 cases (2.0%) 3 patients (2.0%) had a unilateral thickening gasket placed 4 patients (2.7%) had lengthening gasket placed 3 unilateral; 1 bilateral

Clinical Experience----Early results Operation time 25.25±2.37 mins for primary pectus excavatum 63.76±29.15 mins for recurrent pectus excavatum Postoperative hospital stays: 3 to 8 days (mean, 4.85±0.22 days) All patients had a satisfactory orthopedic result at discharge There was no perioperative death or cardiac perforation

Clinical Experience----Follow-up results Follow-up time: 32 – 44 months (mean, 35.8±5.2 months) Steel bars were in the original position in 132 patients (89.8%) before the bar was removed Of the other 15 patients, 3 patients (2.0%) with significant bar shift required reoperation, the bar shifted slightly in 12 patients 134 patients underwent bar removal during the follow-up orthopedic and functional results were excellent in 121 cases (90.3%) Haller index: 2.67±0.18; median, 2.59 No patient had recurrence The other 13 patients are waiting for the bar removal.

Conclusion This novel modified Nuss procedure is a safe, effective, and convenient treatment for pectus excavatum Main advantages of this novel modified Nuss procedure: All the steel bars are premade into different sizes Both bar installation and removal are convenient and less traumatic Less postoperative pain and no limitation of the growth Long-term follow-up are warranted 1. The steel bars are produced before the operation and divided into different sizes. We can choose the suitable bar for each patient. 2. The steel bar is installed or removed by pushing and pulling without flipping, which reduces the difficulty of the operation and decreases intraoperative trauma. 3.The bar is mainly supported by the ribs in our procedure, which can effectively decrease the postoperative pain. Also, the bar is fixed on the anterior chest wall, so it doesn’t limit the normal growth.

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