Combined mastoid/middle cranial fossa repair of temporal bone encephalocele

Surgical management of spontaneous middle cranial fossa defects: a systematic review and meta-analysis of available reconstructive techniques and materials

Different materials and techniques have been proposed for surgical repair of spontaneous middle cranial fossa (MCF) defects. However, conclusive evidence supporting their selection and impact on clinical outcomes is lacking. The study aims to conduct a systematic review and meta-analysis on materials and techniques employed to repair MCF defects and evaluate complications and rates of recurrent cerebrospinal fluid (CSF) leaks. A PRISMA-guided systematic review and meta-analysis were performed using MESH terms and specific keywords including studies published before May 2022. Primary outcomes included recurrence of CSF leak and complication rates by type of reconstructive material and technique utilized. Meta-analyses of proportions were performed using random effects and confidence intervals for individual proportions were calculated using the Clopper-Pearson method. Twenty-nine studies were included (n = 471 cases). Materials employed for repair were categorized according to defect size: 65% of defects were of unknown size, 24% were small (< 1 cm), and 11% were large (≥ 1 cm). Rigid reconstruction (RR) was significantly favored over soft reconstruction (SR) for larger defects (94% of cases, p < 0.05). Complications and recurrent CSF leak rates of SR and RR techniques were comparable for defects of all sizes (p > 0.05). Complication rates reported for these procedures are low regardless of technique and material. RR was universally preferred for larger defects and analysis of complication and recurrence rates did not reveal differences regardless of defect size. While RR was more frequently reported in smaller defects, SR was used by several centers, particularly for smaller MCF floor defects.

An Uncommon Differential for Mass in the Middle Ear Cleft-Temporal Meningoencephalocele

Meningoencephalocoele (ME) of the temporal bone is otherwise known as brain fungus. It is a rare and potentially life-threatening condition. It occurs in cases of chronic otitis media either as a complication or iatrogenically induced following mastoid surgeries. It requires prompt surgical intervention. High-resolution Computer tomography of Temporal bone and Magnetic resonance imaging of the brain are needed to detect these cases. Surgery can be otological, neurosurgical, or combined. We discuss a case of Iatrogenic Temporal meningoencephalocele and its management along with a review of the literature.

Middle Fossa Encephaloceles Treated via the Transmastoid Approach: A Case Series and Review of the Literature

BACKGROUND

Middle fossa (MF) encephaloceles are rare lesions resulting from herniation through defects in the tegmen tympani or mastoideum. Underlying etiologies and clinical presentations are variable. Surgical goals include fistula obliteration, resection of nonfunctioning parenchyma, and dehiscence repair. The middle cranial fossa approach (MCFA), transmastoid approach (TMA), and combined (MCFA + TMA) approaches have been described. The minimally invasive TMA provides excellent exposure of the pathology and allows for ample working room to repair the defect.

OBJECTIVE

We present short-term follow-up results in patients treated via the TM repair at our institution.

METHODS

A retrospective review of patients with symptomatic encephaloceles treated via the TMA by our multidisciplinary team. Patient demographics, clinical presentations, intraoperative findings, repair technique, and outcomes were highlighted.

RESULTS

A total of 16 encephaloceles in 13 patients were treated. Defect etiologies included spontaneous (50.0%), secondary to chronic infection (25.0%), or cholesteatoma (18.8%). Defects were most often within the tegmen mastoideum (68.8%). Average length of surgery was 3.3 h (95% CI: 2.86-3.67) and length of stay 3.9 d (95% CI: 3.09-4.79). On short-term follow-up (average 11.5 mo), no patients experienced postoperative cerebrospinal fluid leak or recurrence. The majority of patients (83.3%) experienced confirmed improvement or stabilization of hearing.

CONCLUSION

MF encephaloceles present with various clinical manifestations and result from multiple underlying etiologies. The TMA is an alternative to craniotomy and our short-term results suggest that this approach may be utilized effectively in appropriately selected cases.

CT of Skull Base Fractures: Classification Systems, Complications, and Management

As advances in prehospital and early hospital care improve survival of the head-injured patient, radiologists are increasingly charged with understanding the myriad skull base fracture management implications conferred by CT. Successfully parlaying knowledge of skull base anatomy and fracture patterns into precise actionable clinical recommendations is a challenging task. The authors aim to provide a pragmatic overview of CT for skull base fractures within the broader context of diagnostic and treatment planning algorithms. Laterobasal, frontobasal, and posterior basal fracture patterns are emphasized. CT often plays a complementary, supportive, or confirmatory role in management of skull base fractures in conjunction with results of physical examination, laboratory testing, and neurosensory evaluation. CT provides prognostic information about short- and long-term risk of cerebrospinal fluid (CSF) leak, encephalocele, meningitis, facial nerve paralysis, hearing and vision loss, cholesteatoma, vascular injuries, and various cranial nerve palsies and syndromes. The radiologist should leverage understanding of specific strengths and limitations of CT to anticipate next steps in the skull base fracture management plan. Additional imaging is warranted to clarify ambiguity (particularly for potential sources of CSF leak); in other cases, clinical and CT criteria alone are sufficient to determine the need for intervention and the choice of surgical approach. The radiologist should be able to envision stepping into a multidisciplinary planning discussion and engaging neurotologists, neuro-ophthalmologists, neurosurgeons, neurointerventionalists, and facial reconstructive surgeons to help synthesize an optimal management plan after reviewing the skull base CT findings at hand. Online supplemental material is available for this article. ^©RSNA, 2021.

Surgical management of middle cranial fossa bone defects: meningoencephalic herniation and cerebrospinal fluid leaks

Along the medical practice of an Otologist he/she will face middle cranial fossa (MCF) bone defects. The purpose of this study is to contribute to the understanding of this possible life threatening condition, and to share and discuss our management approach. A literature review is also presented.

STUDY DESIGN

Retrospective case series at García-Ibáñez Otology and Skull base private center referral.

METHODS

This study is based on the analysis of data collected from 19 cases of temporal bone meningoencephalic herniations surgically treated from 2006 to 2018. The follow-up ranged from 18 to 162 months with a mean average of 44.5 months.

MAIN FINDINGS

Meningoencephalic herniations were divided into four etiologic groups: spontaneous (24.8%), secondary to chronic otitis media (21.8%), iatrogenic (45.9%), and posttraumatic (7.5%). Different surgical techniques were used as treatment: transmastoid (TM) approach (27.8%), MCF approach (27.8%), combined technique (transmastoid plus minicraniotomy, 3%), and middle ear obliteration with blind sac closure of the external auditory canal (41.4%).

CONCLUSIONS

Variables like bilateral hearing level, size and location of the bone defect and existence of CSF leak should be analyzed to select the safest and most effective closing surgical approach.

Otogenic Pneumocephalus After Tegmen Bone Reconstruction: A Case Report

Pneumocephalus is usually induced by trauma, infections, tumors of the skull base, and surgical interventions. Spontaneous pneumocephalus occurs due to a defect in the temporal bone with no obvious cause. Few cases have been reported with spontaneous otogenic pneumocephalus. However, delayed postoperative pneumocephalus is rarely reported in the literature. Here, we present a case of otogenic pneumocephalus through Eustachian tube (ET) preceded by nose blowing 10 days after surgical treatment of meningoencephalocele of the right middle ear (ME) cleft and reconstruction of tegmen and dural defects. Pneumocephalus was provoked by decreased intracranial pressure (ICP) secondary to placement of lumbar drain, which caused direct communication between unsutured dural defect and the defective posterior wall of external auditory canal skin. A revision surgery of combined transmastoid/middle cranial fossa approach was performed for intracranial decompression followed by appropriate closure by suturing the dura, obliterating the ET and ME.

Transmastoid Repair of Spontaneous Cerebrospinal Fluid Leaks

Objective  Determine the efficacy of using a purely transmastoid approach for the repair of spontaneous cerebrospinal fluid (CSF) leaks and further elucidate the relationship of elevated body mass index (BMI) and skull base thickness in our patient population. Method  We conducted a retrospective chart review of patients treated for spontaneous temporal bone CSF leaks at our tertiary care institution from the years 2006 to 2015. Cases were categorized as primary or secondary. We analyzed success rates, length of stay, use of lumbar drains, BMIs, and rates of meningitis. Skull base thickness was compared with BMI in each case. Results  We identified 26 primary operations for spontaneous CSF leaks and 7 secondary operations. Twenty-three of 33 repairs were performed via the transmastoid approach alone with an 87% success rate (20/23). Of the10 repairs including a middle cranial fossa (MCF) or combined MCF-transmastoid approach, 2 failed for an 80% success rate (8/10). Five transmastoid repairs underwent placement of a lumbar drain versus all 10 repairs employing an intracranial exposure. Average length of stay for those undergoing a transmastoid approach (1.7 days) was significantly shorter than for patients undergoing a MCF repair (6.3 days). Four patients presented with meningitis. Average BMI was 35.3. No correlation was established between BMI and skull base thickness ( R²  = 0.00011). Conclusion  The transmastoid approach is effective in the majority of cases and prevents the need for an intracranial operation, resulting in lower morbidity and a shorter length of stay. We believe that this is the preferred primary approach in most patients with spontaneous CSF leaks.

Analysis of Audiometric Outcomes following Combined Middle Cranial Fossa/Transmastoid Approaches for Spontaneous Cerebrospinal Fluid Otorrhea

Outcome Objectives

To (1) explore audiometric outcomes following use of a combined transmastoid/middle cranial fossa (TM-MCF) approach in the treatment of spontaneous cerebrospinal fluid (CSF) otorrhea and (2) determine the influence of dehiscence location and reconstructive methodology on audiometric outcomes.

Study Design

Case series with chart review.

Setting

Tertiary care center.

Subjects and Methods

Adults with spontaneous CSF otorrhea were reviewed from 2007 to 2016 if they underwent combined TM-MCF. Definitive audiometric evaluations were performed at least 3 months postoperatively. The primary outcomes measures were pre- to postoperative changes in pure-tone average (PTA) and air-bone gap (ABG). Two subset analyses were performed for audiometric outcomes comparisons: first, patients with skull base dehiscences anterior to the ossicular chain were compared with those with posterior dehiscences. Second, patients undergoing skull base resurfacing plus abdominal fat graft mastoid obliteration (AFGMO) were compared with those undergoing resurfacing alone.

Results

A total of 28 patients and 31 ears were reviewed. There was 1 recurrent leak (3.5%). The cohort demonstrated significant improvement in mean postoperative ABG ( P = .008) but not PTA. On subset analysis, ears with posterior dehiscences demonstrated significant improvements in PTA ( P = .03) and ABG ( P = .05), while ears with anterior dehiscences did not. In addition, ears undergoing resurfacing plus AFGMO achieved significant improvements on all parameters ( P = .01). Only 3 of 15 ears undergoing resurfacing plus AFGMO experienced worsened postoperative hearing.

Conclusion

Use of the combined TM-MCF approach for treating spontaneous CSF otorrhea achieved good audiometric outcomes. Patients with skull base dehiscences posterior to the ossicles and those undergoing skull base resurfacing plus AFGMO achieved the most favorable results.

Middle Ear Obliteration with Blind-Sac Closure of the External Auditory Canal for Spontaneous CSF Otorrhea

Outcome Objectives To (1) identify unique features of patients who underwent middle ear/mastoid obliteration with blind-sac closure of the external auditory canal for spontaneous cerebrospinal fluid (CSF) otorrhea and (2) explore outcomes. Study Design Case series with chart review. Setting Tertiary care center. Subjects and Methods Adults treated for spontaneous cerebrospinal fluid otorrhea from 2007 through 2015 were reviewed and stratified into 2 groups based on the surgery performed: (1) 11 patients underwent middle ear/mastoid obliteration with blind-sac closure of the external auditory canal and (2) 26 patients underwent other procedures. Demographics, body mass index, revised cardiac risk index, Duke Activity Status Index scores, and anticoagulation use were documented. Audiologic data were gathered from pre- and postoperative visits. The primary outcome measure was leak recurrence. Complications were tabulated. Results Poor preoperative hearing was a relative indication for obliteration. Obliteration patients had higher body mass index (43.2 vs 34.9 kg/m2; P < .05), incidence of super-morbid obesity (45% vs 7.6%; P = .015), anticoagulation usage (36% vs 0%; P = .004), cardiac risk scores (1.2 vs 0.1 dB; P < .0004), and Duke Activity Status Index scores. There was 1 leak recurrence (9%). Major and minor complication rates were 9% and 36%, respectively. Mean follow-up was 30.8 ± 8.6 months. Conclusion Middle ear and mastoid obliteration with blind-sac closure of the external auditory canal is effective for treating spontaneous CSF otorrhea. The small cohort reviewed did not experience any major perioperative morbidity. The technique may be best suited for patients with poor hearing, the infirm, and those in whom craniotomy is contraindicated.

Repair of Temporal Bone Encephalocele following Canal Wall Down Mastoidectomy

We report a rare case of a temporal bone encephalocele after a canal wall down mastoidectomy performed to treat chronic otitis media with cholesteatoma. The patient was treated successfully via an intracranial approach. An enhanced layer-by-layer repair of the encephalocele and skull base deficit was achieved from intradurally to extradurally, using temporalis fascia, nasal septum cartilage, and artificial dural graft. After a 22-month follow-up period the patient remains symptom free and no recurrence is noted.

Fungus cerebri (brain fungus): a rare complication of mastoidectomy

Fungus cerebri is a relatively rare disease. The various reasons attributed to such pathology are, long standing mastoiditis, previous temporal lobe fracture, spontaneous herniation and most important common cause is post operative to mastoidectomy. The diagnosis is mainly clinical and supplemented by imaging studies. The commonly herniated part is the temporal lobe, but cerebellar herniation are also reported Different surgical modalities are used in managing this condition. Surgical approaches in the treatment of brain herniation into the mastoid or middle ear are, neurosurgical, otosurgical and combined. A case of fungus cerebri complicating mastoidectomy is presented and the pathogenesis is discussed.

Use of titanium mesh for middle cranial fossa skull base reconstruction

Objectives Temporal bone encephaloceles are usually encountered in the setting of a congenital defect of the tegmen or as an acquired defect after mastoid surgery. A variety of methods have been described in the literature for rigid reconstruction of tegmen defects. We introduce a new method of repair using orbital floor titanium mesh reconstruction plates to reconstruct the floor of the middle cranial fossa, and evaluate the outcomes, complications, and recurrence rates of temporal bone encephaloceles with this technique. Design Retrospective chart review of consecutively treated patients. Setting Tertiary care academic center. Participants Eight patients with middle cranial fossa skull base defects from January 2007 to February 2011. Main Outcome Measures Outcome measures included resolution of cerebrospinal fluid leak (CSF) and development of postoperative infection. Results One of nine patients had a postoperative CSF (cerebrospinal fluid) leak. There were no long-term complications of CSF leak or infection. Conclusions Titanium mesh is a safe and effective substitute for bone grafts in reconstruction of the middle cranial fossa skull base when rigid reconstruction is required.

Surgical management of temporal meningoencephaloceles, cerebrospinal fluid leaks, and intracranial hypertension: treatment paradigm and outcomes

OBJECT

Thinning of the tegmen tympani and mastoideum components of the temporal bone may predispose to the development of meningoencephaloceles and spontaneous CSF leaks. Surgical repair of these bony defects and associated meningoencephaloceles aids in the prevention of progression and meningitis. Intracranial hypertension may be a contributing factor to this disorder and must be fully evaluated and treated when present. The purpose of this study was to establish a treatment paradigm for tegmen defects and elucidate causative factors.

METHODS

The authors conducted a retrospective review of 23 patients undergoing a combined mastoidectomy and middle cranial fossa craniotomy for the treatment of a tegmen defect.

RESULTS

The average body mass index (BMI) among all patients was 33.2 ± 7.2 kg/m(2). Sixty-five percent of the patients (15 of 23) were obese (BMI > 30 kg/m(2)). Preoperative intracranial pressures (ICPs) averaged 21.8 ± 6.0 cm H(2)O, with 10 patients (43%) demonstrating an ICP > 20 cm H(2)O. Twenty-two patients (96%) had associated encephaloceles. Five patients underwent postoperative ventriculoperitoneal shunting. Twenty-two CSF leaks (96%) were successfully repaired at the first attempt (average follow-up 10.4 months).

CONCLUSIONS

Among all etiologies for CSF leaks, those occurring spontaneously have the highest rate of recurrence. The surgical treatment of temporal bone defects, as well as the recognition and treatment of accompanying intracranial hypertension, provides the greatest success rate in preventing recurrence. After tegmen dehiscence repair, ventriculoperitoneal shunting should be considered for patients with any combination of the following high-risk factors for recurrence: spontaneous CSF leak not caused by another predisposing condition (that is, trauma, chronic infections, or prior surgery), high-volume leaks, CSF opening pressure > 20 cm H(2)O, BMI > 30 kg/m(2), preoperative imaging demonstrating additional cranial base cortical defects (that is, contralateral tegmen or anterior cranial base) and/or an empty sella turcica, and any history of an event that leads to inflammation of the arachnoid granulations and impairment of CSF absorption (that is, meningitis, intracranial hemorrhage, significant closed head injury, and so forth).

The role of obesity in spontaneous temporal bone encephaloceles and CSF leak

OBJECTIVE

Temporal bone encephaloceles and cerebrospinal fluid (CSF) otorrhea can lead to life-threatening sequelae such as meningitis and cerebritis. Obesity has been associated with spontaneous CSF leaks. We wished to determine if there were differences in the body mass index (BMI) of patients with spontaneous temporal bone encephaloceles/CSF leaks and nonspontaneous temporal bone encephaloceles/CSF leaks to help determine if obesity may be associated with their development.

STUDY DESIGN

Single institution retrospective comparison.

METHODS

Demographic and clinical information was obtained from 20 patients treated for surgically confirmed temporal bone dehiscence leading to encephalocele and/or CSF otorrhea. Statistical analysis was performed on patients with spontaneous and nonspontaneous encephaloceles/CSF leaks to determine if there were differences in the degree of obesity between these groups.

RESULTS

Temporal bone dehiscence was spontaneous in 11 patients, related to chronic infection in 4 patients, posttraumatic in 3 patients, postsurgical in 1 patient, and because of massive hydrocephalus in a final patient. The average BMI for patients with spontaneous encephalocele was 33.4 kg/m. The average BMI for patients with nonspontaneous encephaloceles was 27.0 kg/m. This difference was statistically significant (p = 0.02).

CONCLUSION

Although several previous studies have demonstrated an association of obesity with spontaneous encephaloceles or CSF leaks, this study is one of the first to demonstrate a statistically significant increase in BMI for patients with spontaneous encephaloceles and CSF leaks as compared with patients developing them for other reasons. This suggests a potential etiologic role of obesity in the development of spontaneous encephaloceles and CSF leaks.

LEVEL OF EVIDENCE

4.

Spontaneous encephaloceles of the temporal lobe

Encephaloceles are pathological herniations of brain parenchyma through congenital or acquired osseus-dural defects of the skull base or cranial vault. Although encephaloceles are known as rare conditions, several surgical reports and clinical series focusing on spontaneous encephaloceles of the temporal lobe may be found in the otological, maxillofacial, radiological, and neurosurgical literature. A variety of symptoms such as occult or symptomatic CSF fistulas, recurrent meningitis, middle ear effusions or infections, conductive hearing loss, and medically intractable epilepsy have been described in patients harboring spontaneous encephaloceles of middle cranial fossa origin. Both open procedures and endoscopic techniques have been advocated for the treatment of such conditions. The authors discuss the pathogenesis, diagnostic assessment, and therapeutic management of spontaneous temporal lobe encephaloceles. Although diagnosis and treatment may differ on a case-by-case basis, review of the available literature suggests that spontaneous encephaloceles of middle cranial fossa origin are a more common pathology than previously believed. In particular, spontaneous cases of posteroinferior encephaloceles involving the tegmen tympani and the middle ear have been very well described in the medical literature.

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.

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.