Digital Technologies In Accurate For Head And Neck Soft Tissue Reconstruction

The occurring sites and types of head and neck tumors are varieties,which rank the first in systemic tumors.Generally,surgery is the main comprehensive treatment in clinic.Because of the particularity of the anatomy and function of the head and neck,tumor resection will cause different degrees of defects,seriously affecting the appearance,beauty and physiological function.At present,flap transplantation is the treatment of repairing large area of head and neck soft tissue defect,but this kind of operation is very dependent on the clinical experience of surgeons,and the recovery effect is often poor.With the wide application of digital technology in the field of medicine,more and more attention has been paid to the design of digital flap,which has an important research significance for improving the accuracy of soft tissue defect repair and shape recovery.At present,the application of digital technology in flap design mainly focuses on the location of perforating vessels,and there is still a lack of in-depth study on the flap to adapt to the size of the defect area.Based on the analysis of the developability of the various regions of the head and neck surface,the standard head and neck model was reconstructed using medical software,and then based on the Gaussian curvature analysis of the surface,combined with the mechanical constraints and principal curvature analysis methods of clinical soft tissue treatment,an accurate head and neck,the accurate partition of the developable / undevelopable region of the head and neck surface is obtained,and the developing method of the undevelopable surface is constructed.On this basis,the flap design method of head and neck soft tissue defect repair was proposed,and the preliminary clinical application was realized on the basis of in vitro model experiment analysis.The results show that the flap designed by digital technology can improve the accuracy and aesthetic effect of head and neck soft tissue defect repair,and verify the feasibility and validity of digital accurate repair technology of head and neck soft tissue defect after tumor resection.The main research contents and achievements of this paper are as follows:(1)Based on the shape characteristics of the surface,the head and neck surface and the quadric surface were closely matched.Using the developability of the quadric surface,a map of the developable and undevelopable regions of the head and neck surface was obtained.(2)The surface model of the standard head and neck was reconstructed.Based on this,a method of accurately partitioning the developable and non-developable regions of the head,neck and face based on the mechanical constraints of Gaussian curvature analysis and clinical treatment of soft tissue was proposed.Based on the principal curvature analysis method,a flattening method for non-developable regions is proposed,and the comparative analysis of the surfaces before and after flattening is made.(3)Based on three-dimensional reconstruction technology,the design method and process from tumor resection to soft tissue defect skin flap construction were constructed:(1)Reconstruction of the three-dimensional model of tumor and its adjacent tissue to obtain the anatomical structure information of the area to be resected;(2)Design of the repair surface in the area;(3)Designed flap accurate acquisition template,auxiliary shaping template and flap volume controller.(4)In order to verify the effectiveness of accurate digital repair of soft tissue defects,a surgical plan was designed for a case of buccal tumor,and a 1: 1 silicone model of the patient's cheek was copied to perform tumor resection and flap repair simulation surgery.A comparative analysis of the repair model and the design of an ideal repair model shows that the error between the ideal surface and the actual surface after surgery is between 2 mm and 3 mm,and the accuracy meets the clinical needs.(5)Based on the simulated surgery,a personalized surgical template was designed for a tonsil tumor patient according to the digital repair plan,and the 3D printed auxiliary template was used in the patient's clinical surgery.Postoperative evaluation showed that the soft tissue digital repair technology helped patients better restore postoperative swallowing,speech,and other functions,and achieved better skin shape repair results in the defect area.Statistical analysis of patients using digital technology and traditional technology also proves that digital technology has significant advantages in terms of flap utilization,blood loss during surgery,and postoperative recovery time.