IJCS | Volume 33, Nº1, January / February 2019

25 Silva et al. Minimally invasive surgery–pain investigation Int J Cardiovasc Sci. 2020;33(1):24-33 Original Article psychological (insomnia) implications that increase morbidity and mortality. 8,9 In the last few years, there has been a significant increase in knowledge about PO pain and tissue trauma that influence the choice for MI surgical procedures. 1,9 Although a median sternotomy (MS) remains the main access in cardiac surgeries, the intercostal access combined with a MI approach has been progressively used. 2,3,5,6,10 Systematic assessment and treatment of pain is essential after cardiac surgery and can contribute to a faster recovery and rehabilitation of patients. 11 Some studies have reported less PO pain and shorter in-hospital stays after a MI procedure, 1,3,12–14 but the literature lacks a comparative study betweenMS andMI procedures regarding pain intensity (PI). This prospective observational study aims to evaluate the PO thoracic PI by comparing patients subjected to aMI andMS procedures. We evaluated if patients with valve and septal defects subjected to MI procedure have less PO pain compared with those undergoing MS. Materials and methods Study population We evaluated PO thoracic pain in 34 patients who were subjected to MS or MI procedure between June 2015 and June 2016. The Institutional Review Board of the university approved this prospective observational comparative study (approval number 1104.606). We included symptomatic patients presenting with mitral valve (MV) disease or an atrial septal defect (ASD). Exclusion criteria were patients older than 60 years old, patients with body mass index (BMI) (for the MI group only) greater than 32 kg/m 2 , chronic obstructive lung disease, previous heart or thoracic interventions, renal failure, interstitial or inflammatory lung disease, thoracic deformities, mitral valve or aortic calcifications, systolic pulmonary pressure greater than 80 mmHg, coronary artery disease, severe tricuspid valve insufficiency, femoral vessel calcification, femoral artery smaller than 5 mm, moderate or severe aortic valve insufficiency, requirement for re-intervention for any cause after the end of surgical procedure, communication impairments, pain syndrome before the procedure, and patients who withdrew consent at any moment throughout the study. The surgical access technique was chosen according to the pathoanatomical characteristics of each patient and the recommended surgical protocol. The patients were divided in two groups: MS (n = 17) and MI (n = 17). Written informed consent was obtained from all patients before treatment. Surgical technique The surgical procedures were all carried out by the same surgeon (JVC). The patients underwent surgical interventions under general anesthesia and a cardiopulmonary bypass with moderate hypothermia and cold crystalloid cardioplegic arrest. Description of the MS procedure: a main incision of twenty centimeters was performed followed by bone division from the manubrium to xiphoid. A sternal retraction was made to provide a 12-centimeter working space, with full vision of the heart and vessels. The second incision was made two centimeters below main incision for placement of a chest tube drain. Arterial perfusion was achieved by direct cannulation of the ascending aorta. Systemic venous return was achieved with two individual caval cannulas. The aortic occlusionwas made by direct clamping of the aorta. Usual techniques and instruments were applied for the procedure. Minimally invasive procedure: main surgical access was a right minithoracotomy (5 centimeters) into the fourth intercostal space. A periareolar incision and a submammary incision were made for men and women, respectively, between the midclavicular and the anterior axillary line for valve surgery and on the midclavicular line for atrial septal defect closure. The main incision was enlarged with a wound protector and soft tissue retractor (ALEXIS TM ), and a steel retractor was used as necessary during the procedure. Three auxiliary 5 mm ports were placed in the anterior axillary line. In the second space, the port was used for placement of a transthoracic aortic cross-clamp to obtain an aortic occlusion. In the fourth space, a 30-degree high definition camera was placed. In the seventh space, the port was used for atrial venting and CO 2 flow in the operative field at 2 L/min. This port was also used for placement of a 24 F BlakeTM drain at the end of the procedure An atrial lift retractor systemwas positioned at the fourth intercostal space near the sternum, when required. Femoral arterial perfusion was performed using a cannula adjusted for patient’s body surface and internal diameter of the femoral artery. The cannula was inserted by direct puncture using the Seldinger`s technique. The vacuum assisted venous return with a single right femoral venous cannula was associated or not with a right jugular venous cannula. Patients