Hipbone Biomechanical Finite Element Analysis and Clinical Study after the Resection of Ischiopubic Tumors

Objective To investigate the changes of hipbone biomechanics after the resection of ischiopubic tumors and their relationships with the complications in the convalescent stage, and directing the postoperative pelvic reconstruction. Methods DICOM data were used to create an intact hipbone finite element model and postoperative model. The biomechanical indices on the same region in the two models under the same boundary condition were compared. The differences of displacement, stress, and strain of the two models were analyzed with statistical methods. Results The distribution areas of the hipbone nodes' displacement, stress, and strain were similar before and after the simulated operation. The sacroiliac joint nodes' displacement (P=0.040) and strain (P=0.000), and the acetabular roof nodes' stress (P=0.000) and strain (P=0.005) of two models had significant differences, respectively. But the sacroiliac joint nodes' stress (P=0.076) and the greater sciatic notch nodes' stress (P=0.825) and strain (P=0.506) did not have significant differences. Conclusions The resection of ischiopubic tumors mainly affect the biomechanical states of the homolateral sacroiliac joint and acetabular roof. The complications in the convalescent stage are due to the biomechanical changes of the sacroiliac joint and the acetabular roof and disappearances of the stabilization and connection functions of the pubic symphysis and superior ramus of pubis.

Transient Pulmonary Atelectasis after Ketamine Sedation during Cardiac Catheterization in Spontaneously Breathing Children with Congenital Heart Disease

Background:Ketamine is applied widely for sedation during cardiac catheterization in spontaneously breathing children with congenital heart disease(CHD).However,a rare and unreported respiratory complication,transient and reversible atelectasis of lungs(TRAL),was identifi ed.Purpose:The study was performed to investigate retrospectively the prevalence and clinical characteristics of TRAL after ketamine sedation in pediatric cardiac catheterization.Methods:Four thousand four hundred and seventy-four sick children were sedated with ketamine,and pediatric cardiac catheterization was carried out under spontaneous breathing.TRAL was detected in 33 children(17 M/16 F,age was 2.1±1.7 years)by retrospective analysis.The clinical and radiographic characteristics were recorded before,during and after TRAL.Results:In pediatric cardiac catheterization,the prevalence of TRAL was 0.74%after ketamine sedation.TRAL occurred in 23 children with cyanotic CHD,and 10 with acyanotic CHD.All TRALs had common clinical and radiographic features:the diffuse opacity of bilateral lungs developed rapidly(identifi ed under X-ray fl uoroscopy),associated with decrease in lung volume,and then the decrease in SpO2(94.2±9.2%vs.59.4±2.2%,P<0.05),and heart rates(143.5±14.3 bpm vs.58.3±9.7 bpm,P<0.05)followed quickly.TRAL was relieved by supportive oxygen in 32 children(23 with face mask,and 9 with endotracheal intubation),and the duration of TRAL was 1.6±0.5 minutes.However,TRAL caused the death of one child.Conclusions:TRAL is a rare and urgent respiratory complication after ketamine sedation,and the mechanism is unclear.Rapid and diffuse opacity of bilateral lungs is the earliest sign of TRAL in pediatric cardiac catheterization,and the immediate supportive oxygen is crucial.