The Effect of Surgical Repair of Chest on Postural Stability Among Patients With Pectus Excavatum

The experiment was designed as a pretest-posttest control trial. The clinical examination and surgery intervention (minimally invasive repair of pectus excavatum - MIRPE) of pectus excavatum patients are done in Wielkopolska Centre of Pulmonology and Thoracosurgery in Poznań, Poland. Other postural stability assessment of both, experimental group and control group subjects are done in the Poznań University of Physical Education in Poland. The measurements are carried out twice, before and three months after the intervention for experimental group, and twice for control group as well. Before the experiment initial measurements connected to basic and somatic characteristics assessments are recorded. Participants are also familiarized with measurement methods.

All PE patients included in the study after preoperative examination undergo the Nuss surgery procedure (MIRPE): curved metal bars are inserted behind the sternum to correct the shape of the anterior chest wall. The bars are left in situ for three years and then removed. The operation is performed under general anesthesia in a hospital setting.

Postural stability as a dependent variable was examined with the use of the posturography method based on the measurement of centre of pressure (COP) displacements. The stabilometric platform CQStab2P in two-plates version (CQ Electronic System, Poland) is used for collecting COP data during trials. The platforms are equipped with strain gauges that facilitated the monitoring of the changes in ground reaction forces. It is connected to a computer equipped with software provided by the manufacturer of the platforms. Based on the data of ground reaction forces the position and displacements of COP are estimated in the software.

The sampling frequency of 200 Hz is used during data acquisition. According to producer declaration processing accurancy is equal to 0.1% (12-bit processing, effective 10-bit) during reproduction of statokinesiogram with accurancy of 1 mm with radius fluctuation of 10cm.

The force platforms are placed on a hard and flat floor surface. Before the start of the testing procedures, the participants rest in a sitting position for 5 min. During the measurement, only the researcher and the participant are present in the room. Participants need to perform trials in three conditions: 1) double stance with eyes open (EO); 2) double stance with eyes closed (EC); 3) one-leg standing with eyes open (OLS).