Applied Anatomy Of Anterior Decompression And Internal Vertebral Venous Plexus

ObjectivesAt present,there are a variety ways of anterior and posterior approach with cervical vertebra operations.Choosing suitable operation manner and operative approach,according to different pathological changes.However,on clinic,anterior approach of cervical vertebra operations,there are always bleeding in the internal vertebral venous plexuses that impact decompression quality and effect,one or two cases are out of control due to bleeding and the operation can not to be continued.At the moment,the basic anatomy study on the bleeding problem of the internal vertebral venous plexuses,which couldn't integrate sufficiently with the clinic work demand,lack of guidance meaning on the clinic operation and have limit on the way of disposing of thc internal vertebral venous plexuses bleeding.This research is aimed at control efficiently the internal vertebral venous plexuses bleeding during the operation and try to bring forward effective anti-bleeding measures,to give an aid on clinic operation through thc applied anatomy study on thc anatomic structure of anterior decompression range of cervical vertebra and of the anterior internal vertebral venous plexuses,etc to comprehend deeply the structure of the internal vertebral venous plexuses.Research1.Observe and measure the anatomic structure of the anterior internal vertebral venous plexuses and related anatomic data. 2.Simulate anterior decompression operation of cervical vertebral on cadaver specimen,enlarge the decompress scope,measure anatomy symbol and related data.3.Analyse the bleeding reason of the anterior internal vertebral venous plexuses,put forward the safety range of the anterior decompression operation of cervical vertebral and effective anti-bleeding methods.Materials and Methods1.Eight fresh adult(6 male,two female) pate cadaveric specimens (C₁～T₁),check them to exclude the trauma on cervical vertebra, degenerative disease,tumour etc..Then immediately perfused with blue latex and fix the neck artery with formalin when the specimen get ready.Choose another twelve adult pate cadaveric specimens(seven male,five female) which have been antisepticised and fixed.2.Hold the specimen a prostration position and fix it on the dissecting desk,enter it from the back of the centrum and cut off dural sac of the vertebral plate and spinal cord,observing anatomic form of the anterior internal vertebral venous plexus,measuring the distance of anterior internal vertebral venous plexus:the space between two longitudinal venas of the anterior internal vertebral venous plexus.3.According to the anterior decompression operation of cervical vertebrae requirement,anatomise and measure the following structures: (1) inter-anterior crus of uncinate process distance:anterior crus of uncinate process is the stretch part of anterior part of uncinate process and anterior border of vertebrae.(2) the distance between two sides of anterior crus of uncinate process and the medial border of foramen processus transversi.(3) medial border of anterior crus of uncinate process-posterior border of vertebrae;(4) the length of sagittal diameter of centrum vertebrae,measuring by the bisection line on the right and left of the superior margin of vertebrae.4.On the basis of the above measure results,carrying the statistics analysis and analyzing the bleeding reason in the anterior internal vertebral venous plexus and bring forward the safe scope of anterior decompression of cervical vertebra and effective anti-bleeding methods.Results1.Anatomic form of the anterior internal vertebral venous plexus This research focus on observing anatomic form of the anterior internal vertebral venous plexus on 20 cervical vertebrae examples, acquiring that the internal vertebral venous plexuses is in the grease at the outside of dura mate of spinal cord,vein is quite plentiful in plexus form and tight to canalis vertebralis.According to its different location on canalis vertebralis,there are anterior internal vertebral venous plexus and posterior internal vertebral venous plexus.The internal vertebral venous plexuses is an important ingredient in vertebral vein system,vein is plentiful and dense,there are two longitudinal blood vessels in the anterior internal vertebral venous plexuses and its transversal branch is numerous that form transversal ramus communicans.Two longitudinal blood vessels' shape in the anterior internal vertebral venous plexuses are almost same and its arch form is not obvious.The anterior internal vertebral venous plexuses hidden in the dense longitudinal ligament,cling to dura mate of spinal cord. There is no venous valve in the longitudinal vein,most basivertebral veins recirculate to the anterior internal vertebral venous plexus and inflow at the 1/3 segment of the back of centrum vertebrae.The anterior internal vertebral venous plexus can get connected with anterior centrum vertebrae vein through nerve root vein.2.Related anatomy data about body of cervical vertebra uncinate process and foramen transversarium.In C₃～C₇,the distance of longitudinal blood vessel,which in the two sides of the anterior internal vertebral venous plexus,is increase from (11.15±0.21)mm to(14.99±0.27)mm,C₃～C₇ the distance from medial border of uncinate process in centrum vertebrae to the medial border of foramen processus transversi is(5.25±0.85)mm.C₃～C₇ the space of anterior crus of uncinate process increase from(14.61±1.04)mm to (21.48±1.92)mm,anteroposterior diameter of uncinate process exceed 11mm.ConclusionTo solve the plexus venous bleeding problem in the anterior approach of cervical vertebrae,to some extent,is depend on the width of decompression range.In the operation,the anterior internal vertebral venous plexus can thoroughly be observed,so we could look clearly and handle the bleeding more easier and it is the effective anti-bleeding method.Therefore,make sure the safe and effective decompression extent can ensure the operation going on well. According to the anatomic observing results in this group,we bring forward to adopt the inner margin of anterior crus of uncinate process as the orientation mark in the operation.First,it is because of the interior crus of uncinate process is the stretch part of anterior centrum vertebrae and uncinate process and this part is covered by the inner side of collilongus,during the operation,the collilongus can be pushed away and when the intervertebral ligament be cutted down,the interior crus of uncinate process can be fixed on for the location is superficial and easy to be marked;the second,4mm distance from anterior crus of uncinate process to foramen processus transversi that can ensure the safty space.The third,the space of anterior crus of uncinate process is close to the transverse diameter of vertebral canal,which can satisfy the decompression requirement of cervical spinal canal and in this process bone character is not easily be destroyed.The fourth, observing the results,the minimum of the sagittal diameter of centrum vertebrae is(14.84±0.58)mm,the maximum is(16.21±0.51)mm,but the anteroposterior diameter of uncinate process exceed 11mm that can completely satisfy the bone graft demand.Experiment prove that in this extent,the longitudinal blood vessels of anterior plexus can be completely bare,thereby,can prevent bleeding and have better effect on stop bleeding,if the condition is permitted,we can use microscope, applying bipolar coagulation to cauterize longitudinal blood vessels, which can stop bleeding effectively,and do decompression work within the distance of anterior crus of uncinate process,is safe and complete. We can also make the check up better before the operation according to different individual.MRI or MRA can indicate the pathological changes degree,so the operator could make preparation for the bleeding problem of the internal vertebral venous plexuses,working out corresponding operation program to further treat and prevent the bleeding in the internal vertebral venous plexuses.