Temporal Lobe Encephalocele Research Articles

Drainage of middle cranial fossa epidural abscess through mastoidectomy: Our experience and review of the literature

Background: Otitis media (OM) can uncommonly lead to intracranial complications. Epidural abscesses represent a large proportion of cases; however, literature regarding the optimal surgical management of otogenic epidural abscesses is sparse. Favorably located epidural abscesses may be amenable to drainage through a transmastoid approach because the tegmen mastoideum lies immediately inferior to the middle cranial fossa (MCF). Case Description: We report 3 pediatric patients with OM complicated by epidural abscesses of the MCF. The ages ranged from 3 to 6 years old, with 2 females and 1 male. All 3 patients had acute mastoiditis with an abscess of the MCF ranging from 1.6 cm to 6.3 cm at the largest dimension. All patients underwent canal wall-up mastoidectomy with the evacuation of the MCF abscess through a small window, 0.7 × 0.7 cm or less, created in the tegmen mastoideum. All patients were successfully treated through this approach and had complete resolution of their infection on follow-up imaging. There were no postoperative temporal lobe encephaloceles. Conclusion: This is one of the few descriptions of the treatment of an otogenic epidural abscess of the MCF through a transmastoid approach. Collaboration with neurosurgery is vital because their familiarity with the intracranial space helped to guide the accurate direction of dissection. This highlights the importance of a multidisciplinary approach in the treatment of epidural intracranial abscess of the MCF through this approach. The risk of postoperative temporal lobe encephalocele was minimized due to the small tegmen defect size.

Seizures as the Cardinal Manifestation of Idiopathic Intracranial Hypertension: A Case Report

Idiopathic intracranial hypertension (IIH) conventionally presents with features like headache, visual obscuration, diplopia and tinnitus. We present a case of a middle-aged male patient with headache and visual complaints and concurrent drug-resistant right focal seizures. Imaging revealed the presence of a left petrous bone defect with temporal lobe encephalocele with other features suggestive of IIH. Resolution of the symptoms was obtained after placement of theco-peritoneal shunt. Focal seizures in IIH are a rare phenomenon, precipitated by parenchymal herniation through eroded bony defects producing encephaloceles leading to tissue traction and ictal focus formation. In evaluation for drug-resistant temporal lobe epilepsy, IIH-induced encephalocele formation should be carefully considered.

The Diagnostic Challenge of Distinguishing Temporal Lobe Encephaloceles from Sphenoid Sinus Mucoceles

Introduction: Temporal lobe encephaloceles are rare malformations defined as brain parenchyma herniation through a skull base structural defect into adjacent structure such as sphenoid sinus, while sphenoid sinus mucoceles are expansive cystic lesions caused by mucus buildup and thinning of the sinus wall, mostly involving the frontal and ethmoid sinus. Both illnesses may present similar clinical symptoms, such as neurological symptoms, nasal and ophthalmologic symptoms. However, misdiagnosis of temporal lobe encephaloceles can have significant clinical implications, as the best treatment plans vary depending on the disease. Case report: A 27-year-old healthy man who presented with seizure and loss of consciousness in public gave a history of head trauma 13 years back. Upon physical examination, the patient had normal cranial nerve function, and no cerebellar or meningitis signs. Rigid nasoendoscopy showed unremarkable findings. A computed tomography scan revealed an expanded left sphenoid sinus likely mucocele with a left temporal lobe encephalomalacia. Further investigations with brain magnetic resonance imaging (MRI) discovered temporal lobe encephalocele and transcranial repair of sphenoid encephalocele was arranged. Conclusion: Imaging results interpreted incorrectly may result in significant clinical ramifications. Distinguishing between both diseases with a complete investigation including MRI scan is crucial for appropriate management and treatment planning.

Surgical treatment of focal drug-resistant epilepsy associated with temporal lobe encephalocele

In recent years, temporal lobe encephalocele has become more common in patients with focal drug-resistant epilepsy. Despite available experience, there are still no clear recommendations for choosing the extent of surgery in these patients. To evaluate the effectiveness of diagnosis and surgical treatment of focal drug-resistant epilepsy associated with temporal lobe encephalocele. The study included 21 patients with focal temporal lobe epilepsy and temporal lobe encephalocele. All patients underwent continuous video-EEG monitoring and MRI of the brain. There were 12 (57.4%) selective encephalocele resections and 9 (42.6%) anterior temporal lobectomies. The median follow-up period was 31 months. The overall effectiveness of surgical treatment with postoperative Engel class I was 76% (16 cases). Selective encephalocele resection was followed by postoperative Engel class I in 10 patients (83%). There were 6 (67%) patients with similar outcomes after temporal lobectomy. Mean volume of resected tissue adjacent to encephalocele was 8.3 cm3. Surgery is a highly effective treatment for patients with epileptic seizures following temporal lobe encephalocele. In our sample, favorable postoperative outcomes were achieved in 76% of patients (Engel class I). There were no significant differences in effectiveness between selective resection and temporal lobectomy. Further research is necessary for a clear protocol of surgical treatment of focal drug-resistant epilepsy associated with encephalocele.

Temporal encephalocele: An epileptogenic focus confirmed by direct intracranial electroencephalography

Several studies have suggested the epileptogenic potential of temporal encephaloceles. However, there is limited literature describing the results of intracranial EEG monitoring for patients with temporal encephaloceles. We describe a 19year-old right-handed woman with drug-resistant epilepsy who presented with seizure onset at age 16 in the setting of a left temporal encephalocele where the seizure onset zone was confirmed to be the encephalocele via stereo EEG (sEEG). She had focal impaired awareness seizures occurring weekly that would progress to focal to bilateral tonic-clonic seizures monthly. Imaging showed a left anterior inferior temporal lobe encephalocele and a left choroidal fissure cyst that were stable on repeat imaging. Prolonged scalp recorded video EEG recorded seizures that showed either near simultaneous onset in the bitemporal head regions or a transitional left temporal sharp wave followed by maximum evolution in the left temporal region. Invasive monitoring with sEEG electrodes targeting primarily the left limbic system with one electrode directly in the encephalocele captured seizures with onset in the left temporal pole encephalocele. A limited resection was performed based on the results of the sEEG and except for one seizure in the immediate postop period in the setting of infection, patient remains seizure free at her 4month follow up. This report describes a case of drug-resistant focal epilepsy where sEEG monitoring confirmed a temporal encephalocele to be the seizure onset zone without simultaneous onset at mesial temporal or other neocortical structures that were sampled. Our findings support the potential for epileptogenicity within an encephalocele with direct intracranial monitoring.

Refractory Temporal Lobe Epilepsy in Patients with Mosaic Turner Syndrome

Turner syndrome (TS) is one of the most common sex chromosome abnormalities in women, but there are only a few case reports of patients with TS who have epilepsy or seizures. Here, we report two additional cases with drug-resistant temporal lobe epilepsy (TLE) and TS mosaicism. Patient #1 is a 22-year-old female with drug-resistant TLE whose karyotype analysis showed that 84% of interphase cells had (45,X) genotype and brain magnetic resonance imaging (MRI) initially reported as normal showed developmental left temporal lobe encephalocele. She underwent left temporal lobectomy, and she is seizure free for 10-year postoperative follow-up period. Patient #2 is a 49-year-old female who has TLE with normal brain MRI. The karyotype analysis showed that 2/30 of metaphase cells had (45, X) genotype. In addition, 11 cases of epilepsy associated with TS were determined through PubMed. The clinical characteristics of all are reviewed.

The Use of the Exoscope in Lateral Skull Base Surgery: Advantages and Limitations.

We describe our experience using the extracorporeal video microscope, the "exoscope" for various applications within the field of lateral skull base surgery. A retrospective case series was performed investigating patient demographics, indications for surgery, procedure type, operative time, approach to the skull base, complications, adequacy of visualization, and surgeon comfortability. Six cases were performed with a three dimensional surgical exoscope, obviating the use of a traditional binocular microscope. Academic, tertiary referral center. Type of surgical approach, operative time, patient demographics, surgical complications, and surgeon comfortability. The following procedures were performed; four vestibular schwannoma resections via suboccipital craniotomy and two combined transmastoid and transtemporal approaches for temporal lobe encephalocele repairs. The average operative time was 227 and 577 minutes for temporal lobe encephalocele repairs and vestibular schwannoma cases, respectively. No intraoperative complications were encountered during these cases. None of the procedures required abandonment of the exoscope in favor of the microscope during the procedure. Advantages include high-resolution three-dimensional visualization, increased degrees of freedom for exoscope adjustment, and reduced surgeon fatigue in a fixed, unnatural posture. Limitations include decreased depth perception and increased operative time. The exoscope system is a safe and effective alternative or adjunct to the existing binocular operating microscope for lateral skull based procedures. The exoscope provides the surgeon with a comfortable, high-resolution visualization without compromising surgical exposure and patient safety. 4.

C - 17 Case Review: Neuropsychological Evaluation of a Patient with Epilepsy Secondary to Temporal Lobe Encephalocele

C - 17 Case Review: Neuropsychological Evaluation of a Patient with Epilepsy Secondary to Temporal Lobe Encephalocele

Post-operative Temporal Lobe Encephalocele


 This 24-year-old woman presented to ENT outpatients with an enlarging swelling in the right external auditory canal. A radical mastoidectomy for chronic suppurative otitis media with cholesteatoma had previously been undertaken at another institution. On clinical examination there was an otologic mass that was tender on probing.
 High resolution imaging of the temporal bones and a subsequent MRI brain confirmed the mass was a temporal lobe encephalocele.
 A temporal lobe encephalocele is where a segment of the temporal lobe invaginates through a defect in the tegmen tympani. The brain is separated from the middle ear and mastoid process by an exceptionally thin layer of bone – the tegmen tympani. Damage to the tegmen compromises the barrier with the brain and may occur for a number of reasons. This includes congenital, traumatic, post-infectious, malignant invasion, post-radiation therapy and post-surgical causes.1 When this occurs the brain may extrude through the defect resulting in a temporal lobe encephalocele. 
 A bony defect alone, whatever the cause, is insufficient to always result in an encephalocele. Even with dehiscence of the tegmen the dura is capable of supporting the brain issue without herniation. Only when the integrity of the dura is compromised does an encephalocele occur.2 This may be due to the underlying disease process (such as cholesteatoma causing an intracranial abscess) or both purposeful (opening dura to drain an adjacent intracranial abscess) /non-purposeful surgical intervention. Mainstream microsurgical techniques however have lowered the incidence of dural violation.3
 Historically, infection was a major cause, but with the ready availability of antibiotics and prompt management, the key contemporary cause is iatrogenic, following mastoid surgery. However, the overall incidence is uncommon following otologic surgery. In a review of 25 years of middle ear/mastoid encephalocele cases 77% were identified to be iatrogenic in origin.4 
 This patient presented with the finding of a mass observed in the external auditory canal. Less common findings at attendance include tympanic perforation, cholesteatoma, otorrhoea and meningitis.4 
 The key to diagnosis hinges on cross-sectional imaging: combined imaging with CT to assess the osseous structures and MRI for soft tissue review. The high-resolution CT (HRCT) of the temporal bones illustrates a large defect in the right tegmen tympani with a large soft tissue lesion occupying the post-surgical mastoid cavity abutting the tympanic membrane. (Figures 1A, B) The defect of 15mm in the tegmen was more than double the average of 7.2mm reported elsewhere.4 The MRI confirms the defect in the tegmen with the protrusion of a knuckle of the right temporal lobe and its overlying meninges through the defect into the mastoid cavity. The dumb-bell appearance is typical with the narrower neck at the site of the tegmental dehiscence. The extruded brain occupies the post-operative middle ear cavity. (Figures 2 A, B and C) The defect size and volume of herniated brain can be accurately assessed, both of which may be key determinates of the type of surgical procedure.
 Revision mastoidectomy with repair of the tegmen defect and dural integrity using a combined intracranial-mastoid approach is planned as a joint case with neurosurgical colleagues.
 References
 
 McMurphy AB, Oghalai JS. Repair of iatrogenic temporal lobe encephalocele after canal wall down mastoidectomy in the presence of active cholesteatoma. Otol Neurotol. 2005 Jul;26(4):587-94. PMID:16015151
 
 
 
 Neely JG, Kuhn JR. Diagnosis amd treatment of iatrogenic cerebrospinal fluid leak and brain herniation during or following mastoidectomy. Laryngoscope 1985 Nov;95(11):1299-300. PMID:4058205
 
 
 
 Glasscock ME 3rd, Dickins JR, Jackson CG, Wiet RJ, Feenstra L.
 
 Surgical management of brain tissue herniation into the middle ear and 
 mastoid. Laryngoscope. 1979 Nov;89(11):1743-54. DOI:10.1288/00005537-197911000-00005 PMID:502695
 
 
 Jackson CG, Pappas DG Jr, Manolidis S, Glasscock ME 3rd, Von Doersten PG, Hampf CR, Williams JB, Storper IS. Brain herniation into the middle ear and mastoid: concepts in diagnosis and surgical management. Am J Otol. 1997 Mar;18(2):198-205. PMID:9093677
 

Combined Approach for Temporal Bone Defect Repair in Subjects with Cerebrospinal Fluid Otorrhea or Herniations

Objectives: To describe our departmental experience in the surgical repair of tegmen tympani defects, using a combined transmastoid/minicraniotomic approach. Study Design: Retrospective review of videos from surgery and patients' charts. Setting: Tertiary university referral center. Participants: A total of 22 subjects who underwent surgical repair of tegmental defects associated with cerebrospinal fluid (CSF) leakage and/or meningocele/meningoencephalocele by a combined transmastoid/minicraniotomic approach. Main Outcome Measures: A retrospective review of videos of surgery and charts of patients with tegmen tympani or tegmen antri defects and CSF leakage, temporal lobe encephalocele and/or meningoencephalocele. Results: Total 22 subjects underwent the combined approach and all had their defects closed, without significant intraoperative or postoperative complications. Conclusions: Mastoidectomy with temporal minicraniotomy represents an effective approach in patients with tegmen tympani dehiscence; the advantages of this technique are the control of the floor of the middle cranial fossa and the possibility to reach bony defects located anteriorly without manipulation of the ossicular chain and temporal lobe.

Combined approach for tegmen defects repair in patients with cerebrospinal fluid otorrhea or herniations: our experience.

Objectives To describe our departmental experience in the surgical repair of tegmen tympani defects using a combined transmastoid/minicraniotomic approach. Design Retrospective review of videos from surgery and patients' charts. Setting Tertiary university referral center. Participants Twenty-two patients who underwent surgical repair of tegmen defects associated with cerebrospinal fluid (CSF) leakage and/or meningocele/meningoencephalocele by a combined transmastoid/minicraniotomic approach. Main Outcome Measures A retrospective review of videos of surgery and charts of patients with tegmen tympani or tegmen antri defects and CSF leakage, temporal lobe encephalocele, and/or meningoencephalocele. Results All patients underwent the combined approach and had their defects closed, without significant intraoperative or postoperative complications. Conclusions Mastoidectomy with temporal minicraniotomy represents an effective approach in patients with tegmen tympani dehiscence; the advantages of this technique are the control of the floor of the middle cranial fossa and the possibility to reach bony defects located anteriorly without manipulation of the ossicular chain and temporal lobe.

Sternberg′s canal as a cause of encephalocele within the lateral recess of the sphenoid sinus: A report of two cases

Background:Intrasphenoidal encephaloceles are extremely rare findings. Sternberg's canal is a lateral craniopharyngeal canal resulting from incomplete fusion of the greater wings of the sphenoid bone with the basisphenoid. It acts as a weak spot of the skull base, which may lead to develop a temporal lobe encephalocele protruding into the lateral recess of the sphenoid sinus (SS).Case Description:We present two cases of intrasphenoidal encephalocele due to persistence of the lateral craniopharyngeal canal. The first case presented with cerebrospinal fluid (CSF) rhinorrhea and the second one was referred to the neurosurgical department with CSF rhinorrhea and meningitis. Radiological investigations consisted of computed tomography (CT) scan, CT cisternography and magnetic resonance images in both cases. These imaging studies identified a herniated temporal lobe through a bony defect which communicates the middle cranial fossa with the lateral recess of the SS. Both patients underwent a transcranial repair of the encephalocele because of the previous failure of the endoscopic surgery. There was no complication related to the surgical procedure and no recurrence of CSF leakage occurred 2 and 3 years after surgery, respectively.Conclusion:Encephalocele within the lateral recess of the SS is a rare entity which must be suspected in patients who present with spontaneous CSF rhinorrhea. Congenital intrasphenoidal encephaloceles, which are located medial to the foramen rotundum, seem to be due to persistence of the Sternberg's canal. Transcranial approach is a good option when a transnasal approach had failed previously.

Temporal Lobe Encephalocele in the Lateral Recess of the Sphenoid Sinus Presenting with Intraventricular Tension Pneumocephalus

A basal encephalocele often shows an insidious clinical course. Only two cases of temporal lobe encephalocele accompanied with tension pneumocephalus have previously been reported. In this paper, we describe a case of lateral sphenoid sinus encephalocele presenting with intraventricular tension pneumocephalus. A 54-year-old man was referred to our institution presenting with intraventricular tension pneumocephalus. He had undergone ventriculoperitoneal shunt placement for postmeningitis hydrocephalus 3 months before this admission. Precise imaging examinations detected evidence suggestive of a lateral sphenoidal sinus recess encephalocele. Endoscopic transnasal approach was performed for surgical repair of the encephalocele. The encephalocele was removed with subsequent repair of the bony defect. Histological examination showed that the encephalocele includes a part of the ventricular system. This indicates that air might enter directly into the ventricular system after rupture of the temporal lobe encephalocele. A lateral sphenoid sinus encephalocele would potentially cause intraventricular tension pneumocephalus, although pneumocephalus is an extremely unusual complication of this type of basal encephaloceles.

Spontaneous Cerebrospinal Fluid Rhinorrhea Associated With a Far Lateral Temporal Encephalocele -Case Report-

A 35-year-old female complained of right-sided watery nasal discharge persisting for 2 weeks. Neuroimaging investigations revealed a defect in the lateral side of middle cranial fossa, temporal lobe encephalocele protruding into the lateral extension of the sphenoid sinus, and cerebrospinal fluid (CSF) collection on the right side of the sphenoid sinus. The transcranial approach was performed for resection of the encephalocele and obliteration of the cranial base defect anterolateral to the foramen spinosum with transcranial multilayered closure of the defect using autologous fat, cranial bone graft, and vascularized split temporal muscle. At 1-year follow up, the CSF rhinorrhea had not recurred. Transcranial multilayered closure of the defect is safe and reliable, particularly for large CSF fistula at the far lateral sphenoid sinus.

Repair of Iatrogenic Temporal Lobe Encephalocele after Canal Wall Down Mastoidectomy in the Presence of Active Cholesteatoma

Although mastoid and middle ear obliteration provides the ultimate repair of an encephalocele, retained squamous epithelium may result in the occult recurrence of cholesteatoma. For most patients, a preferable technique is to perform a canal-wall-up mastoidectomy with middle fossa craniotomy. However, temporal lobe encephaloceles are occasionally found in patients with canal-wall-down cavities along with active cholesteatoma. We sought to describe our management strategy for this dilemma. Retrospective review. Tertiary referral center. We reviewed all patients with encephaloceles treated by the primary surgeon. Patients without active cholesteatoma and a canal-wall-down cavity were excluded. Surgical management of the encephalocele and cholesteatoma. Successful repair and a noninfected ear. Three patients met the inclusion criteria. All had previous canal-wall-down surgery for cholesteatoma by outside surgeons and presented with chronic otorrhea, large tegmen defects, and brain herniation into the mastoid cavity. All had incomplete removal of their posterior canal wall. Our management strategy involved completing the canal-wall-down mastoidectomy and repairing the temporal floor defect using a three-layer closure via a middle fossa craniotomy. This included suture repair of the dural defect with or without a graft, a temporalis muscle rotation flap, and a split-calvarial bone graft. All patients recovered from their surgery without evidence of further cerebrospinal fluid leak, encephalocele, or cholesteatoma with a minimum follow-up time of 6 months. A temporal lobe encephalocele can be safely repaired while maintaining a mastoid bowl. This may be the safest treatment option for patients with active cholesteatoma.

Temporal Lobe Encephalocele Appearing as a Lytic Lesion of the Skull Base and Pterygoid Process

Meningoencephalocele is an uncommon condition in which brain tissue, meninges, or both protrude through a defect in the anterior cranial fossa and into the ethmoid sinus or nasal cavity. Much less often, brain tissue, meninges, or both protrude through a defect in the middle cranial fossa and into the sphenoid sinus. We report an unusual case of a middle fossa encephalocele that appeared as a lytic lesion of the skull base. The patient was treated successfully via a unique endoscopic transpterygoid approach--that is, an endoscopic approach through the maxillary sinus and pterygopalatine fossa and into the pterygoid process.

Endoscopic Transpterygoid Approach to the Lateral Sphenoid Recess

The endoscopic transpterygoid approach appears to be a viable treatment option for selected patients with an encephalocele or cerebrospinal fluid fistulae from the middle cranial fossa into a lateral sphenoid recess. This case report describes a patient with cerebrospinal fluid leak and seizures in whom a large temporal lobe encephalocele was found. The encephalocele entered the sphenoid sinus through a bony defect in the roof of the lateral recess of a widely pneumatized sphenoid. The endoscopic transpterygoid approach was successfully used to repair the skull base defect. The only disappointing result was that the patient had a reduced sense of smell postoperatively.

Developmental anterobasal temporal encephalocele and temporal lobe epilepsy

The authors describe the association between an antero-basal temporal lobe encephalocele and medically intractable temporal lobe epilepsy in three patients treated successfully by surgery. Two men and one woman, aged 26 to 37 years (mean 31 years), had onset of complex automatism and generalized seizures in their second and fourth decades (mean age 22.7 years). They had been epileptic for 6 to 14 years (mean 8.3 years) before surgery. Preoperative electroencephalograms localized ictal epileptic activity to the left mesial temporal lobe in all cases, and neuropsychological testing revealed dominant temporal lobe dysfunction. Magnetic resonance (MR) imaging demonstrated an anteromedial basal temporal encephalocele extending into the pterygopalatine fossa through a bone defect at the base of the greater sphenoid wing in the region of the foramen rotundum and pterygoid process, a discrete center of embryonal chondrification. At surgery, the encephaloceles were found in front of the uncus, and an area of gliosis extended from the encephalocele to the amygdalohippocampal region. All patients have been seizure-free following anterior temporal resection and amygdalohippocampectomy including the encephalocele. These three cases delineate a condition of disordered embryogenesis wherein a developmental anterobasal temporal encephalocele acts as the substrate for temporal lobe epilepsy. This lesion may be diagnosed preoperatively with MR imaging and should be considered in the differential diagnosis of late-onset temporal lobe epilepsy.

Intractable complex partial seizures associated with occult temporal lobe encephalocele and meningoangiomatosis: A case report

Occult congenital temporal lobe encephalocele has rarely been reported in association with medically intractable complex partial seizures. The four previously reported cases were unsuspected preoperatively. We present the case of an 18-year-old woman with intractable complex partial seizures since age 13. Seizure onset was electrically localized to the right temporal lobe. Preoperative neuroimaging studies revealed a middle fossa defect and inferior herniation of the right temporal lobe. Pathologic examination of the resected encephalocele revealed prominent features of meningoangiomatosis. We believe this to be the first case of temporal lobe encephalocele and epilepsy to be diagnosed preoperatively, and the first case also to be associated with meningoangiomatosis. The relevant literature on meningoangiomatosis and on temporal lobe encephalocele as a cause of epilepsy is reviewed.