Variations of the soft tissue thicknesses external to the ribs in pectus excavatum patients.
BACKGROUND
Surgical repair of pectus excavatum (PE) has become more popular due to improvements in the minimally invasive Nuss procedure. The pre-surgical assessment of PE patients requires Computerized Tomography (CT), as the malformation characteristics vary from patient to patient.


OBJECTIVE
This work aims to characterize soft tissue thickness (STT) external to the ribs among PE patients. It also presents a comparative analysis between the anterior chest wall surface before and after surgical correction.


METHODS
Through surrounding tissue segmentation in CT data, STT values were calculated at different lines along the thoracic wall, with a reference point in the intersection of coronal and median planes. The comparative analysis between the two 3D anterior chest surfaces sets a surgical correction influence area (SCIA) and a volume of interest (VOI) based on image processing algorithms, 3D surface algorithms, and registration methods.


RESULTS
There are always variations between left and right side STTs (2.54 ± 2.05 mm and 2.95 ± 2.97 mm for female and male patients, respectively). STTs are dependent on age, sex, and body mass index of each patient. On female patients, breast tissue induces additional errors in bar manual conception. The distances starting at the deformity's largest depression point at the SCIA are similar in all directions. Some diverging measures and outliers were found, being difficult to find similar characteristics between them, especially in asymmetric patients.


CONCLUSIONS
The Nuss procedure metal bar must be modeled according to each patient's special characteristics. The studied relationships between STT and chest surface could represent a step forward to eliminate the CT scan from PE pre-surgical evaluation.
Life and Health Sciences Research Institute (ICVS), School of Health Sciences, University of Minho, Braga, Portugal; ICVS/3B's-PT Government Associate Laboratory, Braga/Guimarães, Portugal; DIGARC-Polytechnic Institute of Cávado and Ave, Barcelos, Portugal. Electronic address: pedrorodrigues@ecsaude.uminho.pt.
Pedro L
PL
Rodrigues
Bruno
B
Direito-Santos
António H J
AH
Moreira
Jaime C
JC
Fonseca
A C M
AC
Pinho
Nuno F
NF
Rodrigues
Tiago
T
Henriques-Coelho
Jorge
J
Correia-Pinto
João L
JL
Vilaça
D000293:Adolescent; D000465:Algorithms; D000886:Anthropometry; D001940:Breast / Q000473:pathology; D002648:Child; D002675:Child, Preschool; D005260:Female; D005660:Funnel Chest / Q000000981:diagnostic imaging / Q000473:pathology* / Q000601:surgery; D006801:Humans; D021621:Imaging, Three-Dimensional; D008297:Male; D019919:Prosthesis Implantation; D019651:Plastic Surgery Procedures; D012727:Sex Characteristics; D035441:Thoracic Wall / Q000000981:diagnostic imaging / Q000473:pathology*; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome
Computed tomography scan; Image processing; Nuss procedure; Pectus Excavatum; Radiation exposure