|Year : 2019 | Volume
| Issue : 4 | Page : 219-222
Lateral temporal lobe meningoencephalocele: Transmastoid repair with surgicel and temporalis graft
K N Lorna Ting1, Yew Toong Liew1, Narayanan Prepageran2
1 Department of Otorhinolaryngology, Queen Elizabeth Hospital, Sabah, Malaysia
2 Department of Otorhinolaryngology, University Malaya Medical Centre, Kuala Lumpur, Malaysia
|Date of Submission||14-Jul-2019|
|Date of Acceptance||04-Oct-2019|
|Date of Web Publication||4-Dec-2019|
Dr. Yew Toong Liew
Department of Otorhinolaryngology, University Malaya Medical Centre, Kuala Lumpur
Source of Support: None, Conflict of Interest: None
Temporal lobe meningoencephalocele is a rare entity and the acquired etiology is commoner especially from iatrogenic injury to the tegmen during mastoidectomy. Non-specificity of its clinical presentations often lead to delay in diagnosis and its neurological sequalae can be devastating. Hence, both clinical suspicion and imaging are both complementary. Various approaches have been described in meningoencephalocele repair. Here, we described a successful repair of the disease via transmastoid method for a huge tegmen defect, with simple materials, included surgicel and temporalis fascia graft.
Keywords: Surgical, temporal lobe encephalocele, temporalis graft, transmastoid
|How to cite this article:|
Ting K N, Liew YT, Prepageran N. Lateral temporal lobe meningoencephalocele: Transmastoid repair with surgicel and temporalis graft. Indian J Otol 2019;25:219-22
|How to cite this URL:|
Ting K N, Liew YT, Prepageran N. Lateral temporal lobe meningoencephalocele: Transmastoid repair with surgicel and temporalis graft. Indian J Otol [serial online] 2019 [cited 2020 Mar 30];25:219-22. Available from: http://www.indianjotol.org/text.asp?2019/25/4/219/272230
| Introduction|| |
Temporal lobe meningoencephalocele is a rare disease with an estimated incidence between 1/3000 and 1/35,000 cases. By definition, an encephalocele is when cranial contents extend beyond the confines of the skull. Meningocele involves the herniation of only the meninges, while meningoencephalocele includes both the meninges and brain tissues. Temporal lobe meningoencephalocele may happen in those with congenital skull base defect at the tegmen. Acquired causes include iatrogenic injury from skull base surgeries, erosion from skull base tumors, traumatic fracture, and radiation. Nonspecificity of the clinical signs and symptoms of this situation often lead to delay in diagnosis. Untreated cases could lead to devastating complications such as meningitis, intracranial abscess, seizures, and venous infarction. The potential for neurological sequelae makes it an important entity that requires prompt surgical intervention.
| Case Report|| |
A 24-year-old female was referred to our otolaryngology clinic from another private hospital, presented with progressive right ear fullness for 6 months. It was associated with an intermittent gush of clear fluid. She had background hearing loss since 3 years ago due to the right ear cholesteatoma, and she had undergone a canal wall down mastoidectomy in a private hospital, which referred her to us. She denied vertigo, purulent ear discharge. On clinical examination, she was comfortable with intact cranial nerves. Nystagmus and fistula test were all absent. There were no signs of meningitis. Endoscopic ear examination showed a pulsatile lobulated mass occupied the whole external canal, and gentle probing test appeared to show that the mass originated from deeper space [Figure 1]. There was no obvious leak noticed. Her pure tone audiometry revealed a mixed moderate hearing loss on the affected side while the other ear was normal. Computed tomography showed that right middle ear cleft was filled with soft tissue opacity, with an obvious 1.5 cm defect at the tegmen [Figure 2] and [Figure 3]. Magnetic resonance imaging (MRI) of the brain revealed a soft tissue in the middle ear cleft in continuity with the right temporal lobe of the brain, which was consistent with meningoencephalocele [Figure 4]. She then underwent excision and repair through transmastoid approach, and the steps of surgery were as followed. She was well and discharged at day 2 after surgery.
|Figure 1: Endoscopic picture of right ear, showing lobulated pulsatile mass occupied whole external canal|
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|Figure 2: High-resolution computed tomography (axial) revealed a postoperative mastoid bowl with soft-tissue mass on the right side|
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|Figure 3: High-resolution computed tomography of temporal bone (coronal) showed a large defect at tegmen, and significant bony ledges lateral to soft-tissue mass|
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|Figure 4: Magnetic resonance imaging scan showed an encephalocele on the right ear, where the soft-tissue mass was continuous with the dura and brain tissue through tegmen defect|
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Surgical steps are as follows:
- The procedure was done under general anesthesia, and facial nerve monitor was used
- The previous postauricular incision was made, and mastoid cavity was exposed to reveal the encephalocele [Figure 5]a
- The encephalocele was dissected free from all directions except at its stalk, from surrounding adhesions [Figure 5]b
- Base of the stalk was exposed adequately from the removal of lateral bony ledges, with the use of diamond drill [Figure 5]c
- Mass was removed and reduced up to the bony edges with bipolar cautery followed by refashioning of the edges [Figure 5]d
- Two layers of surgicels followed by a 2 cm piece of temporalis fascia were inserted as underlay technique [Figure 5]e and [Figure 5]f
- The whole mastoid cavity was finally filled up and obliterated with soft tissues taken from postauricular skin flap.
|Figure 5: (a) Mastoid cavity was exposed following the previous postauricular incision. (b) Encephalocele was dissected free from adhesion from all edges. (c) Base of the stalk was exposed adequately from removal of lateral bony ledges, with the use of diamond drill. (d) The encephalocele and its content were removed with bipolar cautery. (e) Surgicel was applied onto the defect. (f) Temporalis fascia graft was lastly applied using underlay technique|
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| Discussion|| |
Lateral temporal lobe encephalocele (LTE) is a rare entity, and it is a form of basal encephalocele. It has multiple etiologies and is classified into congenital and acquired. Improper development and ossification of petrosquamous junction were believed to be the reason behind congenital LTE, and it is less common than the acquired type. Labyrinthine malformation, such as superior semicircular canal dehiscence, is another situation associated with LTE due to dehiscent tegmen.
Acquired type of etiologies includes neoplasm, chronic otitis media with or without cholesteatoma, temporal bone traumatic fracture, and iatrogenic injury. Improper use of burr near thinned-out bone tegmen and of monopolar electrocautery on the surface of dura mater may result in injury leading to herniation.
The most common presenting symptoms are conductive hearing loss with a draining ear. Neurological manifestations such as epilepsy, facial neuropathy, and aphasia are uncommon. When barriers retaining cerebrospinal fluid (CSF) within the subarachnoid space become disrupted, CSF leakage with meningitis is the potentially life-threatening sequelae. Meningitis rate will be even higher in underlying infective chronic otitis media with or without cholesteatoma.
Typical otoscopic finding of LTE will be a pinkish pulsatile mass. It may be difficult to recognize in an operated ear by junior doctors as it could mimic polyp or granulation tissues arise deep within from an infected mastoid bowl.
Due to its nonspecific presentation, imaging is crucial, and both computed tomography and MRI are complementary. MRI depicts an interruption of the dural line, and the radiological images appear as “tear-drop.” MRI is also specific in differentiate brain tissues from cholesteatoma, cholesterol granuloma, or granulation tissues.
This situation is managed surgically, and various surgical approaches have been described in world literatures. These approaches include transmastoid from below, middle cranial fossa (MCF) from the above and combined technique. Transmastoid method carries the least morbidity, but it was reported best for repair of small defect at tegmen of <1 cm. MCF approach allows generous exposure to facilitate identification and repair of multiple defects. Ossicular chains are left untouched, and hence, it preserves hearing. However, brain retraction may lead to epidural collection and potential seizure activity. Hospital stay might be prolonged as well. Our senior surgeon decided to utilize only transmastoid technique as we managed to get adequate exposure by removal of lateral bony edges as shown in [Figure 5]c. We believed that any potential seizure activity from MCF approach might lead to increase in intracranial pressure and risk of recurrence of LTE. A careful study of the scans is crucially important, and we showed that transmastoid repair is still possible despite the defect more than 1 cm, as reported.
Various graft use has been reported, such as conchal cartilage, perichondrium, temporalis fascia, fat, and muscle. Synthetic graft is not uncommon, and it includes hydroxyapatite and fibrin glue., In our case, we used surgicel as one of the multilayer reconstructions. Surgicel is a cellulose-based hemostatic agent which forms a stable gelatinous clot which induces fibrosis. Surgicel has been widely used in skull base CSF leak repair and thus far reported no complications.
| Conclusion|| |
Transmastoid route of meningoencephalocele repair is a safe and reliable method, even for bigger defects more than 1 cm. It can be achieved with adequate exposure of encephalocele stalk from the removal of surrounding body ledges. It is the least invasive approach with less morbidity. Simple material such as temporalis fascia and surgicel could provide adequate support, as in our report.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5]