The Digital Design And Clinical Application Of Combined Foot Flaps For Repairing Degloving Injury Of The Thumb And Fingers

Digital degloving injuries are difficult to be repaired by replantation with vessel anastomosis,due to the defect or damage of the degloved skin.Based on the complexity and difficulty of the operation,the treatments could be divided into four stages:amputation,replantation,flap and toe-to-hand transfer.It is difficult to recover the appearance and function of the injured thumb or finger with low morbidity of donor site.Currently,the patients ask for high requirements of the appearance and function of the repaired thumb or finger.It is an ideal method to repair the injury by hallux wrap-around flap or second toe wrap-around flap.If the injury of the donor site is not considered,the restoration of the injured thumbs or fingers repaired by this kind treatment could achieve the level of real ones.It also presents the improvement of microsurgery.Due the decrease of the toe number after harvest of the hallux wrap-around flap or second toe wrap-around flap,the donor site is damaged seriously,becoming a difficult problem in clinical.To reduce the damage of the donor site,we divided the wound of the digital degloving injury into two parts and Put forward the concept of partition repair.The wound of the digital degloving injury was divided into dorsal and palmar parts,which were repaired independently.For thumb degloving injury,great toe nail flap was used to cover the wound,resulting into wound coverage and nail reconstruction;the palmar wound was repaired by ipsilateral and contralateral second medial flap or dorsalis pedis flap,resulting into pulp reconstruction and recovery of finer sensation.Since 2012,we have used the method of partition repair to treat the digital degloving injuries,conducted many kinds of combined foot flaps and gained satisfactory clinical effects.The usage of combined foot flaps for repair of digital degloving injury could recover the perfect appearance of the injured thumb or finger,as hallux wrap-around flap or second toe wrap-around flap did,and not sacrifice the toe number.The method achieves finer microsurgical restoration and presents the latest advance in this field.However,in the clinical practice,we found the judgement of the condition of degloving injuries and the design of intraoperative surgical protocol mainly depended on the clinical experience of the surgeon.To make sure the defect area,geometrical shape of the wound and intraoperative design of tissue flap,it is difficult to design the flap accurately before operation with the support of surgeon's experience and simple tools.Sometimes vascular variation was found after the skin of the donor site was incised during the operation,resulting into the change of surgical protocol,new damage of donor site,and the increase of operative time and difficulty.The development and advance of microsurgery requires a 3D image system which could display the injured condition before operation,vascular structures of donor site,and intraoperative visualized design.This system could change the traditional training pattern for the doctor and offer accurately preoperative design and virtual simulation of surgical procedure.It also could guide how to harvest the flap during the operation.In addition,it could but a three dimensional modeling of wound according to different wounds of degloved injury and could achieve the goal of precision surgical design and decrease of donor site damage.This study combines clinical imaging techniques,computer medical techniques,microsurgical anatomy,flap surgery,and microsurgery techniques and conducts multidisciplinary and interdisciplinary research.3D scanning technology and digital image processing technology are used to build the 3D digital model of digital degloving injuries,divide the wound into two parts and measure the area and geometrical shape of the required flap accurately.3D-DSA arterial angiography is used to detect the type of blood supply of the targeted tissue at the foot donor site to provide evidence for precision surgical design.This project also conducts the visualized study on the combined foot flaps for repair of digital degloving injuries.The content of this study is divided into three parts as followed.The first part:To make a three-dimensional model of the degloving injury of the thumb and fingers.Its objective is to explore the feasibility of creation of 3D model of digital degloving injury by Arigin 3D Pro,Materialise Magics software with image data created by CT scanning,to divide the 3D modeling wound into dorsal part and palmar part according to the concept of portion repair.It will provide the visualized evidence for precision design of combined foot flaps to treat this injury.Fresh specimen of upper limb on one side was selected and scanned by CT to build 3D model of undamaged hand.Then the digital degloving injury at the level of thumb metacarpophalangeal joint,at the level of distal interphalangeal joint of index finger,at the level of proximal interphalangeal joint of middle finger,and at the level of metacarpophalangeal joint of ring finger were created respectively.All the injured thumb and fingers were scanned by CT and the data was saved by DICOM format.Based on the data,the degloved thumb and fingers and degloved skin was rebuilt by medical imaging software(Arigin 3D Pro),resulting into the 3D model of digital degloved injury and degloved skin.All them were divided into dorsal part and palmar part.Then the area and geometrical shape of the required flap were measured.The data measured by manual method and the data of model created by software were imported into GraphPad Prims 7 for statistical analysis to test the accuracy of model data.Flaps were designed for virtual simulation surgery to cover the wound of 3D modeling of digital degloving injury.The results showed that 3D models of degloving injury of thumb,index finger,middle finger and ring finger were created successfully.Clear three-dimensional image of structure of degloved injury and visualized 3D model were got.The degloving level was positioned accurately,and clear boundary with normal skin was found in the 3D model.The model also displayed the anatomy of tendons and bones effectively.3D measurement software was used to measure and segment the area and shape of the palmar and dorsal skin required to repair the wound model of digital degloving injury.It is an easy,quick and intuitive method to design the portion flap.This method could complete free combination design as needed.It could offer stereoscopic,convenient,and intuitive digital reference material for repair of the digital degloving injury by combined foot flaps.Especially,it could measure and segment the degloved skin at the 3D model and offer visualized evidence for surgical design.The actual data of degloved skin measured by manual method and the data of degloved skin model created by software were got for statistical analysis.The Pearson correlation coefficient analysis results suggest that the data of model created by the software has a significant correlation with the actual data of the skin.Second part:The digital design of combined foot flaps for repairing degloving injury of the thumb and fingers.To explore the feasibility of using 3D-DSA angiography technique and three-dimensional reconstruction software to reconstruct the foot vessels and the feasibility of using Philips DICOM Viewer6.0 image viewer software to design the three-dimensional model of combined foot flaps for repairing degloving injury of the thumb and fingers.The reconstructed combined flap model and digital model of degloving injury of the thumb and fingers in the first part were used to design and cut the flaps of the preoperative simulation,and to provide a visualized three-dimensional image for the accurate design of combined foot flaps for repairing degloving injury of the thumb and fingers.Three fresh adult cadaveric lower extremity specimens were selected and 3D-DSA angiography was used.The data was imported into Philips DICOM Viewer 6.0 image browsing software to construct a three-dimensional image of the foot vessels.Combined with the model of the thumb and fingers degloving injury completed and the constructed vascular condition in the previous stage,three kinds of methods three kinds of methods including the combine of big toenail flap and second toe medial flap,the combine of big toe lateral flap and second toenail flap,the combine of big toenail flap and foot dorsal artery flap were designed to virtual simulate the repairing of the three-dimensional model of the thumb and fingers degloving injury were designed to virtual simulate the repairing of the three-dimensional model of the thumb and fingers degloving injury,and the surgical procedure is simulated.We successfully acquired data on the arteries of the foot and veins,as well as their 3D images,and obtained clear stereoscopic vascular structures of the foot and visualized 3600 rotation images.We also accurately constructed the travel,caliber,and morphological distribution of the dorsalis pedis artery,first dorsal metatarsal artery,plantar digital artery,and its main branches we need in this study.In particular,it is possible to visually observe the variability of blood vessels,and provide a precise preoperative design basis for the clinical application of combined flaps.Based on the model reconstructed by DSA angiography and the built-in Philips DICOM Viewer6.0 image viewer software,the surgeon can carry out various forms of free combination design according to the specific conditions of blood vessels,and repair the three-dimensional model of degloving injury of the thumb and fingers.Moreover,the three-dimensional model can be used to simulate surgery,which facilitates the design and cutting of clinical precision surgery.Third part:clinical application of digital design of combined foot flaps for repairing degloving injury of the thumb and fingers.For 8 patients with degloving injury of the thumb and fingers,the CT scanning was used to reconstruct the model and the volar and dorsal skin of the degloving was divided by the three-dimensional software to measure the skin required.The data of 3D-DSA angiography of the lower extremities was transmitted to the Philips DICOM Viewer 6.0 image browsing software to reconstruct the foot artery and its branches.According to the vascular information,the combine of big toenail flap and second toe medial flap is used to repair the thumb,and the combine of second toe medial flap(or the big toe lateral flap)and second toenail flap from ipsilateral or bilateral is used to repair the finger.The flap or the phalanx flap was used to repair the finger and simulate the surgical procedure on a digital model.The surgical procedure is simulated on a digital model.The results showed that 8 patients were reconstructed by CT scan to digitize the injury of the thumb and finger skin.The volar and dorsal skin of the degloving was divided by the three-dimensional software to measure the skin required.8 patients underwent 3D-DSA angiography of the lower extremities,and the distribution of the foot arteries was reconstructed by Philips DICOM Viewer 6.0 image browsing software.According to the vascular information,the combine of big toenail flap and second toe medial flap is used to repair the thumb,and the combine of second toe medial flap(or the big toe lateral flap)and second toenail flap from ipsilateral or bilateral is used to repair the finger.The surgical procedure is simulated in the three-dimensional software.The intraoperative design of the combined flap was identical to the preoperative design.All the 8 cases were repaired with accurate combined flaps,the flaps survived and the skin grafts in the foot donor area were completely alive.A case whose donor site repaired by a free superficial inferior epigastric artery perforator flap occurred partial necrosis at the distal end of the flap.After 4 to 17 months of follow-up,the nails of the thumb and fingers after repair were well-growth,and the feeling of recovery was S2?S3+.The shape was realistic and the evaluation was excellent according to the evaluation criteria of the Chinese Medical Association's thumb and finger reconstruction function.The skin graft in the foot donor area was satisfactory,1 case was mildly pigmented,and the rest was non-pigmented.No obvious scar contracture and skin ulceration were observed,and the patient's walking was unimpeded.Through the research above,we have successfully constructed a digital model of degloving injury of the thumb and fingers,which can clearly,dynamically and stereoscopically display the structural characteristics of the degloving injury.The 3D measurement software can be used to measure and cut the area and shape of the volar and dorsal skin required for the degloving injury of the thumb and fingers.It can be used for simple,fast and intuitive partition flap design,and can be freely combined as needed.It provides an intuitive,three-dimensional,digital reference for the clinical design of the foot combined flap to repair the degloving injury of the thumb and fingers.In particular,the skin required for repairing the degloving injury can be measured,cut,and shaped under three-dimensional conditions,making the surgical design more intuitive and sufficient.Based on 3D-DSA contrast technology and Philips DICOM Viewer6.0 image viewer software,the digital design of the foot vessels can be accurately and effectively constructed.The whole construction process can accurately display the blood vessel classification,caliber,morphological distribution and the variation of the foot vessels.It can meet the design needs of clinically partition repair of the degloving injury of the thumb and fingers.It can make the surgeon easily obtain the area and shape of the required flap and the information of the vessels of the foot before the operation,which helps to accurate the preoperative design.Clinically,CT scan was used to reconstruct the digital design of the injury and the 3D-DSA angiography of the foot was used to reconstruct the blood vessels of the foot.Variety of combined flaps to repair the degloving injury of the thumb and fingers was created.Obtaining foot vascular information,simulated surgical procedures,and precise microsurgical repair before surgery can minimize the damage in the donor area and achieve satisfactory clinical results.