Discussion On The Occurrence And Influencing Factors Of Acute Paradoxical Herniation After Unilateral Decompressive Craniectomy

Objective: The Unilateral Decompressive Craniectomy is regarded as an effective neurosurgical treatment for the rapidly increasing intracranial pressure(ICP).The paradoxical herniation(PH)is one of the rare and serious complications after The Decompressive Craniectomy(DC).However,the occurrence of the paradoxical herniation during the acute period has not received widespread attention.Therefore,this article reports and systematically analyzes the occurrence and influencing factors of this rare complication.Methods: We retrospectively collected 137 patients who underwent DC and ICP probe placement in the First Affiliated Hospital of Shantou University Medical College between January 2018 and September 2019.And 63 patients were selected and divided into two groups to compare their relational factors to find the difference.Results: Through comparison and analysis,it was found that there was considered statistically significant between the drainage of cerebrospinal fluid(CSF),septum pellucidum(SP)shifting value before and after DC,the D-value of the shifting value before and after DC and the operative occasion(P<0.05).In the acute paradoxical herniation(APH)group,by changing the postoperative position,4 patients(4 out of 21,19%)had a significant mental improvement.There was a significant statistical difference in the improvement of Glasgow Coma Scale(GCS)score between the patients with and without adjusting the body position(P < 0.05).Conclusion:Clinically,in the early stage(within 3 days)after DC,there are clinical manifestations such as decreased GCS score,limb paralysis,decreasing flap tension in the operation area and low ICP,and patients with imaging features consistent with paradoxical herniation are often mistaken for the serious course of the primary disease.Through the analysis and discussion of relevant data,we found that its pathophysiological mechanism is similar to PH.We call it acute paradoxical herniation.In patients with APH,the displaced brain tissue was not well reset or relieving during and after the operation.After the operation,the supratentorial high intracranial pressure was reduced and ICP was in a low-pressure state,but the displaced brain tissue could not be reset or relieve satisfactorily.In addition,the influence of body position,brain compliance,brain gravity and hydrostatic pressure after the skull defect led to further compression of important brain structures and disturbance of cerebral blood and spinal fluid circulation.During the operation,the surgeons should pay attention to the good reduction of displaced brain tissue,and adopt the position reversal,hydrotherapy and other measures during or after the operation.Traditionally,the concept of "Reducing ICP" is not enough to alleviate the disease,so it is necessary to establish the concept of "Relieving the Herniation" and the concept of “Reconstruction of Physiological CSF Circulation Balance” to avoid this adverse event.