The Effects Of Abdominal Wall Scar On High-intensity Focused Ultrasound Ablation For Uterine Fibroids

With the micro-non-invasive concepts of“letting patients suffer less harm”,High-intensity focused ultrasound ablation(HIFU)technology is widely used in the clinical treatment of uterine fibroids.With the continuous improvement of clinical treatment strategy,the incidence of treatment-related complications has been gradually reduced.However as the study of ultrasound ablation gradually deepens,the indications of HIFU gradually expand,and there are still complications related to ultrasonic ablation.With more and more uterine fibroid patients with a history of pelvic surgery,especially cesarean section,the safety and efficacy of ultrasound ablation for uterine fibroid patients with abdominal wall scars in the acoustic pathway are worth deeply exploring.ObjectiveTo evaluate the therapeutic efficacy and safety of HIFU ablation for patients with abdominal surgical scars and investigate the factors which may cause thermal injury of abdominal wall structures in HIFU ablation of uterine fibroids.Methods1.A total of 861 patients with uterine fibroids were referred for HIFU treatment in this study.Pelvic enhanced MRI was performed before and after HIFU ablation.There were 202 cases of patients with abdominal wall scars in the acoustic pathway(scar group),and 659 cases of patients without abdominal wall scars in the acoustic pathway(No scar group).The outcomes,intra-operative adverse reactions and post-operative complications between the two groups were compared.2.In the total of 861 patients with uterine fibroids,anterior abdominal wall edema was found in 138 cases(edema group)on postoperative MRI,and 723 cases with no abdominal wall edema(no edema group),Increased pelvic effusion was found in 285 cases(increased effusion group),576 cases with no increased effusion(no increased effusion group).Analyze the relationship between abnormal changes of postoperative MRI and intraoperative adverse reactions and postoperative complications.3.A total of 892 patients with uterine fibroids,after therapy,thermal injury to the skin was assessed via measurement of skin redness,blisters,subcutaneous nodules and to the abdominal wall structures via measurement of signal intensity on T2-weighted MRI images.A total of151 patients were assigned to the injury group,741 patients were assigned to the non-injury group.The relationship between patient and treatment parameters and injury were analysed using non-conditional logistic regression analyses.Results1.The uterine volume ablation rates in the scar group and the non-scar group were(80.31±18.16)%and(79.60±17.57)%,respectively,and the difference was not statistically significant(t=0.497,P=0.620).No serious complications occurred in either group.The incidence of‘hot’skin sensation during HIFU procedure in the scar group[52.97%(107/202)]was higher than that in the no scar group[41.58%(274/659)](χ~2=8.134,P=0.004).There was no significant difference in the incidence of postoperative complications between the two groups(P>0.05).2.Anterior abdominal wall edema was found in 40 cases(40/202,19.80%)in abdominal scars group and 98 cases(98/659,14.87%)in no scar group on post-operation MRI(χ~2=2.793,P=0.095).Increased pelvic effusion was found in 60 cases(60/202,29.70%)in abdominal scars group and 225cases(225/659,34.14%)in no scar group on post-operation MRI(χ~2=2.793,P=0.241).The incidence of pain during operation was 81.15%in edema group(112/138),and hot skin sensation was 57.97%(80/138),which were higher than those in no edema group.Difference was statistically significant(P<0.05).The skin injury rate in edema group2.90%(4/138)was higher than that in no edema group 0.14%(1/723),(χ~2=10.885,P=0.001).3.The postoperative MRI showed no significant difference in the incidence of adverse reactions intro-operation between increased pelvic effusion group an no increased effusion group.The rate of lower abdominal pain 45.96%(131/285)and skin injury 1.40%(4/285)after treatment in increased pelvic effusion group were higher than those in no increased effusion group,difference was statistically significant(P<0.05).4.Univariate logistic regression revealed that sonication time(P=0.000,OR=2.123,95%CI 1.764-2.556),sonication time per hour(P=0.000,OR=1.523,95%CI 1.287-1.801),total energy deposited(P=0.000,OR=2.180,95%CI 1.807-2.630),distance from uterine fibroid ventral side to skin(P=0.046,OR=1.175,95%CI 1.003-1.377),volume of uterine fibroids(P=0.011,OR=1.229,95%CI 1.048-1.441),abdominal wall scar(P=0.000,OR=1.602,95%CI 1.092-2.350),abdominal wall thickness(P=0.000,OR=1.570,95%CI 1.329-1.854)and BMI(P=0.000,OR=2.097,95%CI 1.575-2.745)all affected whether thermal injury occurred(p<0.05).Subsequently,multiple logistic regression analysis revealed that total energy(P=0.000,OR=2.228,95%CI 1.831-2.712),abdominal wall scar(P=0.019,OR=1.639,95%CI 1.085-2.477)and abdominal wall thickness(P=0.000,OR=1.562,95%CI 1.313-1.857)were significantly correlated with thermal injury.Conclusions1.The effective ultrasound ablation dose can be tolerated in patients with uterine fibroids and scar on the abdominal wall.After strict screening of cases,it is safe for HIFU to treat uterine fibroids with abdominal wall scar in the acoustic channel.2.The abnormal manifestation of abdominal wall edema and increased pelvic effusion can be displayed on MRI after HIFU treatment.Changes in abdominal wall edema are associated with intraoperative hot skin,and may be an early change in the appearance of skin burns.Increased pelvic effusion was associated with lower abdominal pain.3.BMI,abdominal wall thickness,sonication time,abdominal wall scar,sonication time per hour,total energy deposited,distance from uterine fibroid ventral side to skin and volume of uterine fibroids all affected whether thermal injury occurred.Abdominal wall thickness,total energy,and abdominal wall scar were the most significant influencing factors that influenced minimal thermal injury of abdominal wall structures in HIFU ablation of uterine fibroids.