Is cranioplasty the optimal treatment for contralateral subdural effusion after decompressive craniectomy?: a case report.

Introduction and importance: Contralateral subdural effusion (CSDE) is a rare complication secondary to decompressive craniectomy (DC), which can lead to encephalocele and neurologic deterioration. The authors report a case that confirm the existence of unidirectional membrane valve, and cranioplasty is an effective treatment for CSDE. Case presentation: The authors reported a case of 43-year-old female was diagnosed with ruptured intracranial aneurysm and treated with interventional embolization. She underwent DC because of postoperative cerebral infarction subsequently. Her conscious state deteriorated accompanied by encephalocele in postoperative 2 week. A craniocerebral computed tomography (CT) confirmed the diagnosis of CSDE with cerebral hernia. A compression bandaging of the skull defect was applicated, whereas, her conscious state progressive deteriorated. She was transferred to the author's hospital where she underwent burr-hole drainage and clinical symptom has been improved. However, a relapse of CSDE was observed after the removal of drainage tube. Continuous lumbar drainage was employed, and which was ineffective for CSDE in this case. Finally, she underwent cranioplasty, with the help of drainage of subdural effusion, CSDE was completely resolved. Clinical discussion: CSDE is occasionally observed in patients after DC. Intracranial pressure (ICP) gradient and unidirectional membrane valve are the possible mechanisms of CSDE. At present, there is no optimal therapy for CSDE. For symptomatic CSDE patients, one or more treatment measures should be applicated. Conclusion: Cranioplasty is one of the curative and optimal method to treat symptomatic CSDE patients, early cranioplasty combined with burr-hole drainage should be performed for conservative treatment failed and intractable cases.