The Design And Application Of Three-dimensional Positioning Device For Anteiror Nasal Spine Of Maxillary Using In Surgery

In recent years, with the improvement of people’s living standardand the rhythm speeding up, comprehensive hip fracture incidencecaused by trauma has increased year by year. Comprehensive treatment ofhip fracture has put forward new challenges to modern oral andmaxillofacial surgery.For severe comminuted fracture, old fractures andcomplicated fracture with most of the hard and soft tissue defectcombined fracture, conventional treatment can not get good reductioneffect.For fractures with the completely lost of nose forehead pillar,zygomatic alveolar ridge wings pillar, upper pillar and so on three bigpillar structure maxillary position will be more uncertain.Defect in thereengineering process of maxillary after tumor resection needs to beconsidered the height and degrees of the upper jaw.In addition,maxillary’s height or degree of malformations and orthognathic surgery also need toorientate the degree and height.To restore the height and degrees of theupper jaw is the fundamental purpose of the above treatment.Above ANS of maxillary is cavity structure.It occupies most ofmaxilla and has big influence on height of maxilla.Under ANS ofmaxillary are the teeth and alveolar process.They are physical structureand occupy the small part of maxilla.Their height is a constant and haveless effect on height of upper jaw. Hence, the distance between ANSand N point can be represented the height of the upper jaw. ANS in themaxilla is the most outstanding point, so its location can be on behalf ofthe sudden degree of maxillary. The normal ANS are located in themid-line.Above all the three points, ANS can represent the height anddegree of upper jaw. To restore the height and degrees is thepurpose of treatment of fractures, developmental malformation andreconstruction.And, in most cases, the base of the midpoint of the S and N rootpoint is constant and not to be affected.So, we can determine the height and degrees of the upper jaw just to make sure the spatial location of ANSand N.Studies have found that the probability of comprehensive hipfracture with skull base fracture and displacement at the same time is verysmall.The stability of the base position inspires us to employ the positionlocation of the skull base maxillary spatial location, so as to guide theclinical treatment of maxillary position.The preliminary experiment on816cases of normal maxillary fragments on the base of space positioncontrolled epidemiological studies done by the group has found that:Different gender：<N-P-ANS Angle is a fixed value；PN Linespacing and P-ANS Line spacing have significant linear positivecorrelation.Comprehensive in patients with hip fracture:N-ANS couldcalculated by the following formula male female；Based on the above theoretical results,PN line spacing date can be measured through the X-ray head positioning.We can determine thespace coordinates and position of ANS by calculation formula of N-ANShigh N-ANS distance, so as to determine the height and degree of theupper jaw, and to determine the spatial location of maxilla.How to apply the theoretical data prior to surgery to determine thethree-dimensional space of the upper jaw ANS? If needs a kind ofauxiliary positioning device. The purpose of this experiment wasdesigned to make such a device to make the patients with preoperativewear head side positioning device of the piece, and according to thepreliminary experiment and the calculation method of simulation on theX line piece.Then mark normal ANS point position, and mark thelocation of the device point.and then measuring the distance and routebetween ANS and mark point to use in the intraoperative.So whetherthe positioning device has operability and the theoretical data and ANScan be transferred in to intraoperative through the measurement andpositioning positioning device are the purposes of this experiment.We put the device into the wearing according to the last position during intraoperative,and then adjust it to the preoperative markers inposition according to the measured data.Thereby the virtual maxillaryANS point can be shifted to intraoperative.Visible, the device need to beworn in the preoperative and intraoperative twice. So whether the devicestwo relative to the position of the skull is overlap or not, directly relate toits reliability. So the test repeatability and reliability of picking withmany times and reducing the error factor is also one of the purposes ofthis study.This design and construction of the maxillary fractures inpositioning and measuring device with the aluminum alloy material.30people selected in the normal population randomly wearing with thedevice were taken X-ray head positioning slice to determine whether NSdot overlap and identify whether the device has the location of thestability and the reliability of data.20people selected in the normalpopulation randomly wearing with the device were taken X-ray and thenwe move direction and distance positioning landmark to confirm whetherthe appraisal theory signalized point and positioning landmark are overlap or not.So to identify whether the device has practical operability.We use the normal crowd maneuverability for the identification ofthe positioning device. The experimental results show that the positioningtheory of point and marking points is the same point and confirm thestrong practical operability of the device.On premaxillary nasal ridge point of three-dimensional positioningdevice can apply theoretical data to guide in the operation onpremaxillary ANS point of three dimensional positioning, to determinethe height and processes of the upper jaw; Used repeatedly withrepeatability, error can be ignored, reliable use, convenient, the threedimensional positioning device has a certain scientific nature andaccuracy, and is worth promoting.