Surgical management of dural and temporal lobe herniation into the radical mastoid cavity

A modification to the fascia-bone-fascia technique for repair of the middle fossa floor

A commonly used method for resurfacing of the middle fossa floor is the fascia-bone-fascia technique. One disadvantage of this technique however is the occasional migration of the bone graft. To prevent this, we have modified the technique to include securing of the graft using simple craniotomy fixation materials. We have now used this method in five patients, all of whom have had satisfactory clinical outcomes. Follow-up imaging has demonstrated the grafts to have remained in their original position.

Combined mastoid/middle cranial fossa repair of temporal bone encephalocele

Temporal bone encephalocele (TBE) has become less common as the incidence of chronic mastoid infection and surgery for this condition has decreased. Due to its declining incidence, the diagnosis of TBE may be delayed and result in the development of serious complications such as cerebrospinal fluid leak, meningitis, epidural or subdural abscess. Six cases of large (>1 cm) TBE of diverse etiology are described. Two patients had suffered previous temporal bone fractures, two had had prior mastoidectomy, and two patients had long-standing chronic mastoiditis. Two patients had undergone prior unsuccessful transmastoid repair. All patients underwent successful tegmen-dural repair with autogenous fascia, bone, and/or cartilage, primarily via a combined mastoid-middle fossa approach. Accurate dural closure and support of intacranial contents are imperative to prevent recurrence. We find that permanent repair can best be performed with a combined mastoid middle cranial fassa approach.

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

OBJECTIVE

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.

STUDY DESIGN

Retrospective review.

SETTING

Tertiary referral center.

PATIENTS

We reviewed all patients with encephaloceles treated by the primary surgeon. Patients without active cholesteatoma and a canal-wall-down cavity were excluded.

INTERVENTION

Surgical management of the encephalocele and cholesteatoma.

MAIN OUTCOME MEASURE

Successful repair and a noninfected ear.

RESULTS

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.

CONCLUSIONS

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.

Transmastoid Repair of Minor Skull Base Defects with Flexible Hydroxyapatite Sheets

This prospective open pilot study was designed to assess the suitability of flexible composite sheets of polymer and hydroxyapatite (HA) for the reconstruction of limited lateral skull base defects through a conservative transmastoid approach.Seven patients with a petrous bone dehiscence less than 3 cm in diameter, either iatrogenic or caused by chronic otitis media or temporal bone trauma, underwent a mastoidectomy. The defect was repaired with the new material and a connective tissue graft. All bone defects were detected by computed tomography (CT) of the temporal bone except one that was found at surgery in an asymptomatic patient.Outcome was evaluated in terms of anatomical integrity of the tegmina, absence of cerebrospinal fluid leaks, side effects, and extrusion and complication rates. None of the patients suffered from immediate side effects related to the implant or the operation. With a minimum follow-up of 18 months (maximum, 62 months), neither extrusion nor a foreign body reaction occurred. Postoperative CT confirmed a satisfactory anatomic contour. Although the number of patients is limited, these preliminary results are encouraging and indicate a need for further clinical trials with a material that allows a minimally invasive approach to selected skull base defects.

[Spontaneous middle ear meningoencephalic herniation. 2 case reports]

Two cases of idiopathic brain herniation into the middle ear without previous surgery are reported. Brain herniation is an unusual pathology, usually related to middle ear surgery. The idiopathic appearance of this disease is the secondly most frequent cause. Its origin is believed to be related to a congenital defect of tegmen timpani. Two elements, both rare, are emphazised: the spontaneous bilateral presentation in one of the cases, and the CSF leak as an initial symptom. We present a review of the literature, describing epidemiology results and the main accepted etiology theories. We discuss the diagnosis and treatment methods: magnetic resonance imaging and surgery.

Middle cranial fossa approach for the repair of spontaneous cerebrospinal fluid otorrhoea using autologous bone pate

Tegmen plate defects causing cerebrospinal fluid (CSF) leaks and brain hernias have conventionally been repaired using soft tissue grafts by a transmastoid approach. A review of the literature reveals that the results of transmastoid repairs have been less than satisfactory. We present here four patients with spontaneous CSF otorrhoea who had tegmen defects repaired using the middle cranial fossa approach. An autologous bone pate slab mixed with fibrin glue with additional temporalis fascia reinforcement was used for the repairs. All four patients had uneventful postoperative periods and have had no subsequent CSF leak (follow-up range: 1-3 years). We believe that the middle cranial fossa approach is more effective than the transmastoid approach for the repair of CSF leaks and brain hernias through tegmen plate defects. An important additional benefit is hearing preservation. We also recommend the use of bone pate along with soft tissue for the repair in order to achieve a secure seal. Bone pate can effectively seal multiple defects in the tegmen plate without any risk of migration.

[Post-surgical and post-infectious meningoencephalic herniation in the middle ear]

Meningoencephalic hernia of the middle ear, due to the advent of antibiotics, the surgical microscope, and the new surgical techniques for the treatment of chronic otitis media, is an infrequent pathology in the presents days. The goal of this paper is to present four cases of meningoencephalic hernia of the middle ear, three of then postsurgical and the remaining of inflammatory origin. Diagnosis, treatment and complications are discussed. Meningoencephalic hernia of the middle ear is usually asymptomatic and diagnosis is accidental. Immediate surgical treatment is indicated in order to avoid the potential complications of this disease. Transmastoid approach has been used for three cases and a middle cranial fossa approach was used in the fourth patient.

Brain herniation and chronic otitis media: diagnosis and surgical management

Herniation of the brain into the middle ear is a rare, but potentially life-threatening complication of chronic otitis media. Fifty patients with a tegmen defect associated with chronic otitis media were operated on between 1985 and 1998. Among these 50, 15 patients presented brain herniation associated with the bony defect. Fourteen patients had undergone previous mastoid surgery for chronic otitis media. Neurological symptoms were encountered in five patients. In 10, magnetic resonance imaging (MRI) was performed before surgery, and a diagnosis of brain herniation could be made. The hernia was repaired in all patients using a middle fossa craniotomy, combined with a transmastoid approach in 11 cases where a large hernia, and/or inflammatory tissues were present in the mastoid. The herniated brain tissue was resected in all, and the dural and bony defects were closed with fascia and bone. No complication or recurrence occurred, during a mean follow-up of 2 years. In conclusion, the occurrence of severe neurological complications as a consequence of brain herniation emphasizes the necessity for recognition and appropriate management of this disease. Computerized tomography (CT) scanning allows the suspicion of brain herniation, but a definitive diagnosis can best be established with an MRI study. The hernia should be repaired using a middle fossa craniotomy, combined with a transmastoid approach in one or two stages, when necessary.

A method of treatment for persisting cerebellar encephalocele of the temporal bone

Temporal lobe herniation or meningoencephaloceles through the tegmen bone are rare entities but are well-described lesions in the literature. They can be successfully approached through the middle fossa alone or combined with a transmastoid approach, and are repaired with fascia, bone, or cartilage. However, cerebellar encephaloceles penetrating the posterior fossa dural plate and presenting as pulsatile postauricular mass are rare. In this paper, we report successful treatment of a cerebellar encephalocele by cranialization of the mastoid cavity using a calvarial bone graft and closure of the external auditory canal. A prior suboccipital approach, as recommended by others, had failed. The patient has remained well for 1 year with no recurrence.

Meningoencephalic herniation into the middle ear: a report of 27 cases

Meningoencephalic herniation into the middle ear is a rare and potentially life-threatening condition that may require prompt surgical intervention. Preoperative diagnosis is based on a high index of suspicion. Sometimes, however, meningoencephalic herniation is discovered during surgery. High-resolution computed tomography and magnetic resonance imaging should be performed to confirm the diagnosis and to evaluate the extension of the herniated tissue. This article discusses the diagnostic approach, management strategy, and surgical technique used in 27 patients with meningoencephalic herniation. In an attempt to avoid infective complications, the authors used the middle cranial approach in patients with large herniations.

Histopathology of spontaneous brain herniations into the middle ear

Two patients with spontaneous brain herniation into the middle ear have been operated on with a combined otoneurological approach. In case No. 1, two 2 x 3 mm arachnoid tissue herniations were found in the tegmen antri of the left ear. Six years later, a 8 x 9 mm mass consisting of prolapsed brain was removed from the right ear. The histological examination showed normal but disorganized nervous tissue. The surface consisted of middle ear mucosa or modified glial cells. More deeply numerous well preserved neurons and synapses were observed. In case No. 2, a 2 x 1 cm herniation was found in contact with the ossicles and the bony walls of the middle ear. The herniation consisted of partly degenerated nervous tissue which could explain the episode of temporal lobe seizure the patient experienced 8 years before surgery. In the world literature during the last 40 years, 29 cases of spontaneous or idiopathic brain herniation into the middle ear and mastoid have been reported. In 10, the herniations were multiple, as in our case No. 1. Case No. 1 is interesting also because the spontaneous brain herniation was bilateral.

Tegmental dehiscence and brain herniation into the middle ear cleft

The tegmen tympani may occasionally be breached by herniation of the temporal lobe with or without dural cover. The clinical presentation may be obvious with CSF otorrhoea but less so with apparent middle ear effusion, CSF rhinnorrhoea, conductive hearing loss, recurrent meningitis or intracranial sepsis. Diagnosis requires suspicion of the condition, which may be aided by radiological imaging. Surgical repair is to be recommended: various techniques are available but bone enveloped by fascia placed by subtemporal approach is preferred. The features of this problem are highlighted by four cases.

Postauricular cerebellar encephalocoele secondary to chronic suppurative otitis media and mastoid surgery

Cerebellar herniation into the mastoid through the posterior aspect of the temporal bone as a result of chronic suppurative otitis media and mastoid surgery is a rare event. A case is reported in which such a hernia presented subcutaneously behind the pinna; its repair is discussed.

Brain herniation into the middle ear cavity: MR imaging

A CT and MR study of a case of brain hernia within the middle ear cavity is reported. MR allows differentiation between brain tissue and other abnormalities of the ear with a similar appearance on CT.

Middle fossa surgery. Report of 153 cases

The principal indications for the middle cranial fossa approach to the petrous apex and internal auditory canal are section of the vestibular nerves in vertigo, management of lesions of the labyrinthine segment of the facial nerve, and removal of mass lesions of the internal auditory canal. We report 153 cases of pathosis of the temporal bone and related structures for which this approach was used.