Case Report e25 Spontaneous Delayed Brain Herniation through a Subdural Membrane after Tumor Surgery Jean-Pierre Kalala Okito2 Marjan Acou3 1 Department of Neurology, Ghent University Hospital, Ghent, Belgium 2 Department of Neurosurgery, Ghent University Hospital, Ghent, Belgium 3 Department of Radiology, Ghent University Hospital, Ghent, Belgium Karel Deblaere3 Dimitri Hemelsoet1 Address for correspondence Annelies Van Dycke, MD, PhD, Department of Neurology, Ghent University Hospital, De Pintelaan 185, Ghent 9000, Belgium (e-mail: Annelies.VanDycke@UGent.be). J Neurol Surg A 2013;74(Suppl 1):e25–e29. Abstract Keywords ► brain herniation ► complication after neurosurgery ► subdural hematoma ► subdural membrane Background and Importance We report on a rare case of spontaneous cerebral herniation through a subdural membrane in a 54-year-old patient. Brain herniation in adults as a complication of chronic subdural hematomas shortly after a neurosurgical intervention is rare. We are the first to report a case of delayed local herniation in an adult patient more than 1 year after a neurosurgical procedure. Clinical Presentation The patient suffered from a low-grade oligodendroglioma since 1993. Radiotherapy was then applied, followed by resective surgery and chemotherapy in 2008 because of tumor progression. Subsequently, he developed a symptomatic subdural hygroma treated with a subduro-atrial cerebrospinal fluid shunt. In January 2010, the shunt was occluded. Follow-up brain imaging showed a stable situation after tumor resection, with a cyst in the temporal resection cavity and a stable subdural hygroma. In February 2011, the patient visited the emergency department because of an acute right hemiparesis and progressive motor aphasia. Urgent magnetic resonance imaging was suspicious of a herniation of brain parenchyma in the left middle cranial fossa. Explorative surgery showed a locally incarcerated brain herniation through a membrane with a ring-like aperture. Resection of this membrane led to normalization of the position of the brain tissue and to clinical improvement. Conclusion Brain herniation through a subdural membrane is an extremely rare complication, but must be a differential diagnosis in patients with a known chronic subdural hematoma or hygroma and clinical deterioration, even in the absence of recent surgery. Urgent surgical intervention of the herniated brain is recommended to reduce the risk of permanent neurological damage. Case Report Previous History and Current Situation A 54-year-old patient was diagnosed with an oligodendroglioma WHO (World Health Organization) grade II in 1993, located in the left mesiotemporal region. He was treated with received December 21, 2011 accepted after revision February 15, 2012 published online December 18, 2012 radiotherapy (60 Gy) and developed refractory epileptic seizures (treated with antiepileptic drugs) and sustained memory deficit. Follow-up brain magnetic resonance imaging (MRI) in 2008 showed focal contrast enhancement in the residual tumoral tissue. The focus was also an active region on © 2013 Georg Thieme Verlag KG Stuttgart · New York DOI http://dx.doi.org/ 10.1055/s-0032-1320027. ISSN 2193-6315. This document was downloaded for personal use only. Unauthorized distribution is strictly prohibited. Annelies Van Dycke1 Dirk Van Roost2 Spontaneous Delayed Brain Herniation Van Dycke et al. Fig. 1 Comparison of the MRI from January 2011 (left) with the MRI from February 2011 (right) after the onset of the acute right hemiparesis. (A) T2 sequences: the left temporal cyst is replaced by tissue and the (nonfunctional) proximal shunt catheter (red arrow) is displaced from the medial temporal to the left anterobasal temporal region. (B) Fluid attenuated inversion recovery sequences: additional hyperintense anomalies in the left periventricular region with edema in the left temporal region. MRI, magnetic resonance imaging. Fig. 2 After opening the dura, the brain surface and meningeal layers appeared to be covered by a white transparent membrane. In the anterior part of the middle cranial fossa, a brain herniation was found to be incarcerated in a ring-like aperture of this membrane. Journal of Neurological Surgery—Part A Vol. 74 Suppl. 1/2013 positron emission tomography (PET)-computed tomography (CT) and thus very suspicious of a local malignant progression. Clinically, a concomitant increase in seizure frequency occurred. In April 2008, a resection of the left temporal pole with amygdalohippocampectomy was performed. Pathological examination revealed an oligodendroglioma WHO grade III. Chemotherapy with temozolomide was started. In the postoperative period, the patient developed a motor aphasia, found to be caused by a hygroma. A left subduroatrial cerebrospinal fluid (CSF) shunt was inserted, and led to a marked improvement of the aphasia. Due to the shunt, however, a contralateral (right) subdural collection formed, leading to a chronic subdural hematoma. In January 2010, the left subduro-atrial shunt was found to be occluded and the right subdural hematoma was evacuated. Follow-up imaging findings were comparable to those immediately after tumor resection with a cyst in the temporal resection cavity and a stable subdural hygroma, confirmed by following control MR images until January 2011. This document was downloaded for personal use only. Unauthorized distribution is strictly prohibited. e26 Spontaneous Delayed Brain Herniation e27 edema in the left temporal region (►Fig. 1B). The first suspicion of an explosive higher grade tumor recurrence was not supported by PET-CT. Eventually, the tissue in the temporal region was interpreted as a herniation of brain parenchyma with traction on the corticospinal tract, explaining the acute neurological deterioration. Ventricular pressure measurement did not show increased intracranial pressure nor gave arguments for a hydrocephalus. Therefore, an operative exploration was planned. Operation Procedure The cerebral herniation was approached through a left frontotemporal craniotomy, and the subdural shunt catheter was removed. The dura mater was opened. The brain surface and meningeal layers were covered by a white transparent Fig. 3 Widening of the ring-like membrane aperture and subsequent microsurgical resection of the whole membrane of the brain surface (A, B). The membrane appeared to be attached to the tentorium and this part was also resected (C, D). In the depth, a remaining part of the membrane is seen (D, blue arrow). After complete membrane resection, the cerebral peduncle, the posterior cerebral artery, and the oculomotor nerve were exposed (E), and the herniated brain structure retook its normal position (F). Hermetic dural closure was followed by replacement of the bone flap (not shown). Journal of Neurological Surgery—Part A Vol. 74 Suppl. 1/2013 This document was downloaded for personal use only. Unauthorized distribution is strictly prohibited. In February 2011, the patient was shortly admitted to the neurology department because of cervical pain on musculoskeletal basis. The complaints improved with physiotherapy and muscle relaxants, and the patient was discharged. One week later, he came to the emergency department because of the acute development of a right hemiparesis and a progression of his known motor aphasia. Urgent MRI showed a decrease of the subdural hygroma in the left frontoparietotemporal region with small (subacute) blood components left temporally. The left temporal cyst was replaced by brain tissue, and the position of the (nonfunctional) proximal shunt catheter was displaced from the medial temporal to the left anterobasal temporal region (►Fig. 1A). Additional hyperintense anomalies on the fluid attenuated inversion recovery sequences were found in the left periventricular region with Van Dycke et al. Spontaneous Delayed Brain Herniation Van Dycke et al. membrane (presumably from the temporal cyst which developed after the temporal resection in 2008). In the anterior part of the middle cranial fossa, an incarcerated brain herniation was found to protrude through a circular opening in this membrane (►Fig. 2). The membrane was incised and microsurgically resected (►Fig. 3A, B). The membrane was additionally attached to the tentorium and was resected (►Fig. 3C, D). Finally, the cerebral peduncle, the posterior cerebral artery, and the oculomotor nerve were exposed (►Fig. 3E), and the herniated brain structure retook its normal position (►Fig. 3F). Hermetic dural closure was followed by replacement of the bone flap. Postoperative Course No complication occurred during the postoperative phase. The patient already showed a partial recovery of the right hemiparesis after 1 week of intensive physio- and occupational therapy. Also intensive speech training was started, with slight improvement of the aphasia. Follow-up imaging showed a complete regression of the left temporal herniation and the anterior left temporal fossa was re-filled with CSF. The patient went to a rehabilitation center for further recovery. After 6 months (in August), clinical re-evaluation with follow-up imaging took place. Clinically, the patient was further improved and able to walk independently. Speech recovered to the since 2008 known level. Control MRI was comparable to the postoperative imaging (►Fig. 4). Discussion We describe a rare case of cerebral herniation through a subdural membrane with traction on the corticospinal tract. The first report on this topic dates from 19921 and to date, only six cases of cerebral herniation have been reported as a complication of chronic subdural hematomas. Of these, four cases occurred in the pediatric population,1–4 and the other two in adult patients.5,6 In the case reports of adult patients (57 and 77 years), the brain herniation happened shortly after the neurosurgical procedure, namely, a partial membranectomy for an organized chronic subdural hematoma6 and an evacuation of a chronic subdural hematoma with a small craniotomy without dural closure.5 In the pediatric cases (mean age 12 months), the time interval between surgery and herniation was at least 7 months. It has been hypothesized that rapid brain growth and flexibility due to a lack of myelination lead to a greater risk of herniation compared with adults.4 Also, the cerebral pulsation appears to play an important role in the extrusion of cerebral tissue into the subdural space.3,6 In the adult case reports, local cerebral edema after the surgical evacuation of the hematoma has been proposed as the trigger for the local brain herniation.5,6 In our patient, we could not identify a clear trigger for the development of the acute herniation. Of course, since the deterioration occurred suddenly, an epileptic seizure (with Todd’s paresis) was an important differential diagnosis, especially since the patient was known to have epilepsy. Based on the results of the emergency MRI, we could exclude this diagnosis. No recent trauma or epileptic seizure preceded the acute hemiparesis, and there was no history of severe coughing fits. A link with the subduro-atrial shunt seems also less likely. In the past, intracranial pressure problems induced aphasia, but this improved after shunt placement. However, this left subduro-atrial shunt was already inactive since more than 1 year (which was confirmed during the surgical intervention). Ventricular pressure measurement could not show an increased intracranial pressure nor signs of a hydrocephalus. Fig. 4 Control MRI 6 months after surgery (August 2011) shows the regression of the left temporal herniation and the anterior left temporal fossa is filled with CSF (T2 sequences, left image). On the fluid attenuated inversion recovery sequences (right image), the hyperintense anomalies in the left periventricular region remain present. This is comparable with the postoperative imaging (not shown). MRI, magnetic resonance imaging. Journal of Neurological Surgery—Part A Vol. 74 Suppl. 1/2013 This document was downloaded for personal use only. Unauthorized distribution is strictly prohibited. e28 Spontaneous Delayed Brain Herniation Summary We describe the unusual case of a spontaneous brain herniation in an adult patient through a subdural membrane more than 1 year after a neurosurgical intervention. This is a very rare complication with functional and possible life-threatening consequences; however, this complication is treatable. We want to point out that local brain herniation must always be considered in case of unexpected clinical deterioration in patients with a chronic subdural hematoma or hygroma, even in the absence of recent surgery. e29 Conflict of Interest None References 1 Naidich TP, Altman NR, Braffman BH, McLone DG, Zimmerman RA. Cephaloceles and related malformations. AJNR Am J Neuroradiol 1992;13(2):655–690 2 Acakpo-Satchivi L, Luerssen TG. Brain herniation through an internal subdural membrane: a rare complication seen with chronic subdural hematomas in children. Case report. J Neurosurg 2007;107(6, Suppl):485–488 3 Ceccherini AF, Jaspan T. Cerebral herniation through a subdural membrane defect following non-accidental injury. Clin Radiol 1999;54(8):550–552 4 Motoyama Y, Isaka F, Nabeshima S. Internal intracranial encephalocele reduced by a subdural-peritoneal shunt. Case illustration. J Neurosurg 2002;96(5):966 5 Doglietto F, Sabatino G, Policicchio D, Tirpakova B, Albanese A. Transcranial cerebral herniation after chronic subdural hematoma treatment with no dura closure. Neurology 2006;67(3):493 6 Kusano Y, Horiuchi T, Seguchi T, Kakizawa Y, Tanaka Y, Hongo K. Local brain herniation after partial membranectomy for organized chronic subdural hematoma in an adult patient: case report and review of the literature. Brain Inj 2010;24(9):1118–1121 Journal of Neurological Surgery—Part A Vol. 74 Suppl. 1/2013 This document was downloaded for personal use only. Unauthorized distribution is strictly prohibited. Therefore, we concluded that this herniation was a spontaneous event. To our knowledge, this is the first report on delayed brain herniation in an adult patient with a chronic subdural hematoma, more than 1 year after a neurosurgical intervention. Fortunately, resection of the membrane and release of the herniated brain structure led to a gradual improvement of the neurological deficit. We conclude, in analogy with the previous case reports, that urgent surgical intervention of the herniated brain is recommended to reduce the risk for irreversible herniation with permanent neurological damage. Van Dycke et al. Copyright of Journal of Neurological Surgery. Part A. Central European Neurosurgery is the property of Georg Thieme Verlag Stuttgart and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. Copyright of Journal of Neurological Surgery. Part A. Central European Neurosurgery is the property of Georg Thieme Verlag Stuttgart and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use.