| Studying background:TE(traumatic encephalocele)in craniotomy for TBI(traumatic brain injury)is a clinical entity of complications.It refers to intraoperative brain protruding from the decompressive craniectomy site,which is beyond the edge of the craniectomy window and can not be put back into the cranial cavity.It can occur during the lesions evacuation,at the moment of clipping of dura mater,and after the removal of the lesions.Traumatic encephalocele progresses rapidly,causing the important structures such as the thalamus and brainstem to oscillate rapidly,causing severe secondary damage.At the same time,the protruding brain from the craniotomy is severely incarceerated against the edge of the craniectomy site,and the functional area is seriously damaged.If unrecognized,this delayed hematoma and resulting brain swelling can cause devastating damage.Patients traumatic encephalocele had poor outcome,heavy nerve damage,high disability rate,and a mortality rate of 60%to 73%.TE is different from cerebral encephalocele during craniectomyconducted on unilateral brain tumor and intracerebral hemorrhage.In unilateral brain tumors,there is no injuryon the side contralateral to the tumor before brain protruding during surgery.Multiple lesions and delayed injury are characteristics of TBI.Before the brain encephalocele in patients with TBI,there may be clear injury demonstrated by brain CT scans and potential damagethat can not be identified by CT.TE is faster and more severe than that occursduring craniectomy forcerebral tumours and intracerebral hemorrhage,which may be related to the sudden aggravation of preexisting or potential mass effcet injury on the contralateral side.Jorgen found in 1977 that with progressing herniation,the compression of the midbrain will cause obstruction to the cerebrospinal fluid passage down the aqueduct.Moreover,any kind of unilateral supratentorial mass large enough to produce tentorial herniation with obstruction of the aqueduct will also produce contralateral lateral temporal horn widening owing to shielding effect of basal midline barrier against pressure effect from the mass lesion ipsilateral tothetentorial herniation.After Jorgen's study,research on the different effects of different changes in the dilated and disappeared ventricle of the cerebral ventricle on the tentorial herniation in patients with TBI are rarely reported.The dynamic changes of the indirect mass effect signs such as the morphology of the temporal horn and the compliance of the brain in the cerebellum can not only indirectly reflect the mass effect of the tentorial hernia,but also the early mass effect caused by brain damage such as swelling and scattered bleeding.It is a big challenge for neurosurgeons to find a definitive and effective method for evidence-based medicine to predict the risk of brain swelling during surgery and to avoid secondary damage caused by brain swelling.The CRASH and IMPACT study predictive models included midline shift distance,occlusion of the cerebral cistern,and hematoma,but did not include volume changes in intracranial lesions and dynamic changes in mass effects.The literature abroad on the correlation between acute encephalocele and risk factors in TBI is focus mainly on case reports of the formation of contralateral epidural hematoma in the process of intraoperative acute brain swelling.It is concluded that patients with epidural hematoma in the craniotomy often suffered the skull fracture on the side contralateral to original hematoma,the study of large sample cases is very rare.However,Piepmeier thought if this mechanism was operative,it would be anticipated that the occurrence of contralateral epidural hematoma would be reported more frequently.It was reported that only 18%of patients with contralateral calvarial skull fracture developed contralateral epidural hematoma following decompressive craniectomy in the study by su.The role of intracranial pressure monitoring in the diagnosis of contralateral epidural hematoma following decompressive craniectomy is still unclear.The intracranial pressure was not critically high during the period of intracranial pressure monitoring before contralateral epidural hematoma diagnosis.There were also single-center intracranial pressure tests in patients with encephalocele in TBI,hypertensive cerebral hemorrhage,and spontaneous subarachnoid hemorrhage.The results showed that there was no significant difference in intracranial pressure between the three groups,while the intracranial pressure after bilateral craniotomy was significantly lower than that before surgery for three groups.In the domestic literature,there are few prospective studies on the risk factors of intraoperative acute brain swelling.The conclusions of retrospective studies are basically consistent with those of foreign reports.It is generally believed that occurrence of Contralateral epidural hematoma following decompressive craniectomy may be due to relief of the tamponade effect on the contralateral epidural bleeding source,upon opening of the skull.The epidural hematoma is more likely to form on the contralateral side in case of contralateral skull fracture,especially that fracture line is across the middle meningeal artery,and the gap of fracture is over 3 mm.However,Other possible causes include preoperative herniation,diffuse brain swelling,preoperative hypoxia,brain stem injury,injury to surgery time that can lead to intraoperative acute brain swelling?Hemorrhage in the distal part of the operation is one of the common causes of acute brain swelling during surgery.Preoperative cerebral palsy,diffuse brain swelling,preoperative hypoxia,brain stem injury,injury to surgery time and intraoperative acute brain swelling is closely related.However,most patients in clinical practice do not have typical impact fractures.It is difficult to predict encephalocele for patients with no skull fractures during surgery.How to predict the occurrence of acute brain swelling in craniotomy when the craniotomy is not performed on the side of contrecoup is a challenge for surgeons.We investigated whether a specific combination of initial head CT-scan findings about potential mass effect of the brain swelling is a factor in predicting intraoperative acute encephalocele.For the surgical treatment for intraoperative acute brain swelling,there are insufficient data to support one method,and there are still many problems to be solved.The change of brain injury volume after TBI is dynamic,and this dynamic change is the essential cause of brain swelling in craniotomy,The mass effect also changes dynamically with the change of the occupancy damage volume,while it demonstrate the change on both sides of the midline.The dynamic changes of intracranial hematoma or brain contusion,brain edema in relation to the dynamic changes of the mass effect has not explicitly been included in most models.We hypothesize that the correlation between the volume of occupancy damage and disappearanceof the temporal horn controlateral decompression cranicetomy is a predictor of intraoperative brainprotrusion and should be incorporated as such in future prognostic models.To the best of our knowledge,study of the dynamic changes of intracranial hematoma or brain contusion,cerebral edema and the dynamic changes of the occupancy effect and the risk of intraoperative acute brain swelling has not been reported.The correlation between dynamic changes of intracranial mass effect and the risk of intraoperative acute brain swelling was studied prospectively in our study.CT scan findings such as disappearance of temporal horn of lateral ventricle opposite to craniotomy side and diffuse brain swelling,difference between midline shift distance and thickness of hematoma,preoperation time,bilateral intracranial injury,preoperative time,which reflect the ultimate mass due to different causes,maybe better to evaluate factors of intraoperative encephalocele systemically.Firstly,the characteristics of the dynamic changes of temporal horn of lateral ventricleopposite tocraniotomy side and diffuse brain swelling,difference between midline shift distance and thickness of hematoma,preoperation time,bilateral intracranial injury,preoperative time during the preoperative observation were observed.Logistic regression analysis and dummy variable analysis were used to explore the correlation between intraoperative brain swelling and the risk factors and protective factors of encephalocele,which provided a theoretical basis for bilateral craniectomy.OBJECTIVE:To observe the characteristics of preoperative dynamic changes of possible risk factors for encephalocele,to explore the risk factors of acute brain swelling in TBI,to choose the strategy of bilateral craniectomy,and to provide surgery stategy with preoperative evaluation and statistical theoretical basis.METHODS:This study was a prospective research,approved by the medical ethical committee of our hosipital.Inclusion criteria:age>18 years old;have a history of brain trauma;trauma to the first brain CT examination time within 4 hours;Glasgow coma score(GCS)3 points to 10 points;brain CT examination revealed significant intracranial hemorrhage or Brain contusion.Exclusion criteria:previous neurological related diseases,severe circulatory system,respiratory system,urinary system disease;application of anticoagulant drugs,antiplatelet drugs or coagulopathy in the past 7 days;platelet count ? 50×10 9/L;bilateral frontal cerebral contusion,brain stem contusion or brain stem hematoma,diffuse axonal injury;family members refused contralateral craniotomy and died;died during craniotomy;did not undergo craniotomy;in pregnancy,Childbirth or childbirth in the past 30 days;patients with severe combined injuries requiring emergency extracranial surgery;surgical contraindications or allergic reactions to narcotic drugs.(1)Patients with TBI who met the inclusion criteria who were randomly selected were offered medical treatment according to the third edition of the US Guidelines for the Treatment of Severe TBI.After admission,the brain CT was dynamically reviewed,and the morphology of the temporal horn of lateral ventricle opposite to craniotomy side,diffuse brain swelling,difference between midline shift distance and thickness of hematoma,preoperation time,bilateral intracranial injury,preoperative time,the preoperative GCS,and the dynamic changes of the preoperative pupil were observed.The nurse recorded the patient's GCS score and pupillary changes every 30 minutes,and the brain CT was reviewed every time the GCS decreased by one point(2)Finally,total 675 patients with craniectomy were enrolled,and they were divided into encephalocele group and non-encephalocele group according to whether there was brain swelling during operation.First,univariate chi-square test was conducted to indentify different factors.Further,multivariate logistic regression was used to analyze the statistically significant factors in the chi-square test between the brain swelling and the non-encephalocele group.Stepwise regression was employed to establish the risk factors for intraoperative acute brain swelling.The risk factors were then analyzed by dummy variables,and the correlation between different dummy variables and encephalocele was compared.Combined with the statistical analysis of the risk factors of brain swelling and the comparison of different prognosis of 170 patients with brain swelling,the effective and feasible emergency treatment measures for patients with acute brain swelling were summarized.(3)Statistical analysis:Statistical analysis was performed on the data using spss20.0 statistical software.The normal distribution data is represented by ? ± s.The count data is represented by the number of cases?Univariate analysis was performed using chi-square test,multivariate analysis was performed by logistic stepwise regression analysis,and risk factors and protective factors were further analyzed by dummy variable logistic regression analysis.The observation indexes of the two groups of patients were used as independent variables,and whether acute brain swelling occurred during the operation was the dependent variable.The odds ratio(OR)is used to indicate the strength of the relationship between the two,(OR>1 is the risk factor and OR<1 is the protection factor).P<0.05 had significant difference?RESULTS:Acute brain swelling during the operation occurred in 170 patients who underwent contralateral craniectomy.505 patients had no acute brain swelling immune to bilateral craniectomy.Compared with no encephalocele group,disappearance of temporal horn of lateral ventricle opposite to craniotomy side,difference between midline shift distance and thickness of hematoma,diffuse brain swelling,preoperation time,bilateral brain injuries,contralateral cranial fracture,dilated pupils in encephalocele group had statistically significance(P<0.05),while age,gender,obliteration of the third Ventricular in encephalocele group had no statistically significance(P>0.05).Multivariate logistic regression analysis showed that disappearance of temporal horn of lateral ventricle opposite to craniotomy side(95%CI2.399-212.276,OR=22.569,P=0.002),diffuse brain swelling(95%C/9.052-1796.089,OR=124.169,P<0.05),bilateral brain injuries(95%C/1.104-7.256,OR=127.506,P<0.001)were indepengdent risk factors,and difference between midline shift distance and thickness of hematoma(95%CI0.012-0.235,OR=0.053,P<0.001);preoperation time(95%CI0.032-0.389,OR=0.112,P=0.001)were protective factors.Dummy variableanalysis revealed there was no significant difference between the flattened group and the enlarged group of temporal horn of lateral ventricle(P>0.05),as well as the 4?6 hours group compared with the over 6 hours group(P>0.05).A total of 23 underwent bilateral craniotomy and decompression simultaneously,A total of 80 patients with progressive encephalocele during operation underwent contralateral craniectomy consecutively after CT scan.Bilateral decompressive craniectomy was done on 67 patients who developed acute cerebral encephalocele when the dura was cut,as soon as the intraoperative ultrasonography was conducted.Glasgow outcome scale(GOS)results in 3 groups of patients with brain swelling are as following:in the direct bilateral craniotomy group:2 deaths after surgery(GOS grade ?),6 poor prognosis(GOS ? grade and Grade ?),15 patients had a good prognosis(GOS grades ? and ?).in the brain CT scan group,12 patients died(GOS grade ?),41 patients had poor prognosis(GOS grade ? and ?),and 27 patients had good prognosis(GOS grade IV and grade ?).in the ultrasonography group,7 patients died(GOS grade ?),22 patients had poor prognosis(GOS grade ? and ?),and 38 patients had good prognosis(GOS grade ? and grade ?).The difference in prognosis between the three groups was statistically significant.Conclusions:(1)In patients with TBI,There is a clear correlation between preoperation time and acute encephalocele.It is the best observation time window within 4 hours after TBI because brain injury is unstable and aggravates rapidly.Dynamic brain CT scans within 4 hours after TBI can demonstrated significantly different mass effect changes between patients who would suffer acute encephalocele and or not.The risk of acute brain swelling during decompressive craniectomy was significantly increased within 4 hours after TBI.(2)In the case of brain injury enlarging,midline shift gradually increases,temporal horn contralateral to the original hematoma is gradually widening,and the risk of acute encephalocele during decompressive craniectomy decline significantly.(3)When severe brain injury is enlarging,midline shift slightly,temporal horn contralateral to the brain injury is gradually disappearing or disappeared directly,the incidence rate of acute brain swelling during surgery is significantly high.(4)The difference between the midline shift distance and the hematoma thickness ipsilateral to the midline shift is larger,that is,under the compression of the same thickness hematoma,the greater the midline shift distance,indicating that the compliance of the brain tissue contralateral to the midline shift is better,and the risk of intraoperative brain swelling is lower.Vice versa,the lesser the midline shift is,indicating a severe mass effect,and the risk of intraoperative brain swelling is significantly increased.(5)There are great risks for encephalocele when midline shift mildly with thicker hematoma,difference between midline shift distance and thickness of hematoma is small,disappearance of temporal horn contralateral to the original hematoma,or diffuse brain swelling.Effective management strategy of operation such as bilateral decompressive craniectomy and operation procedure should be taken preoperatively in case of great risks for encephalocele. |
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