Endoscopic treatment of middle fossa arachnoid cysts.

BACKGROUND: Endoscopic treatment of middle fossa arachnoid cysts is an alternative option to microsurgical fenestration and shunting procedures. The procedure is minimally invasive and obviates the morbidity of craniotomy and shunting. METHODS: Operative charts and videos of patients undergoing endoscopic fenestration of middle fossa arachnoid cysts were retrieved from the senior author's database of endoscopic procedures and reviewed. Description of the surgical techniques was then formulated. CONCLUSIONS: Endoscopic fenestration of middle fossa arachnoid cysts entails communicating the cyst cavity to the basal cisterns via multiple fenestrations that should be made as large as possible with care to avoid injury of the juxtaposed neurovascular structures.

Middle fossa approach for resection of vestibular schwannoma.

BACKGROUND: Surgical approaches for removal of vestibular schwannoma are done through retrosigmoid, translabyrinthine, or middle fossa approaches, depending on the tumor size, preoperative hearing status, surgical team experience, and patient preference. The middle fossa approach (MFA) for the vestibular schwannoma (VS) route preserves hearing and can be done with minimal morbidity and mortality. METHOD: The authors discuss the surgical anatomy of the middle fossa, internal auditory canal localization techniques, MFA indications and the procedure for VS removal, and outcome. CONCLUSION: Unlike otolaryngologists, who use the MFA to treat various pathological processes that involve the inner or middle ear, many neurosurgeons are unfamiliar with the MFA. Nevertheless, learning the technical nuances of the MFA adds to the neurosurgeon's armamentarium, especially for treatment of small intracanalicular VSs in young patients who wish to preserve hearing.

Middle infratemporal fossa less invasive approach for radical resection of parapharyngeal tumors: surgical microanatomy and clinical application.

Surgery of the infratemporal fossa (ITF) and parapharyngeal area presents a formidable challenge to the surgeon due to its anatomical complexity and limited access. Conventional surgical approaches to these regions were often too invasive and necessitate sacrifice of normal function and anatomy. To describe a less invasive transcranial extradural approach to ITF parapharyngeal lesions and to determine its advantages, 17 patients with ITF parapharyngeal neoplasms who underwent tumor resection via this approach were enrolled in the study. All lesions located in the ITF precarotid parapharyngeal space were resected through a small operative corridor between the trigeminal nerve third branch (V3) and the temporomandibular joint (TMJ). Surgical outcomes and postoperative complications were evaluated. Pathological diagnosis included schwannoma in eight cases, paraganglioma in two cases, gangliocytoma in two cases, carcinosarcoma in one case, giant cell tumor in one case, pleomorphic adenoma in one case, chondroblastoma in one case, and juvenile angiofibroma in one case. Gross total resection was achieved in 12 cases, near-total and subtotal resection were in 3 and 2 cases, respectively. The most common postoperative complication was dysphagia. Surgical exposure can be customized from minimal (drilling of retrotrigeminal area) to maximal (full skeletonization of V3, removal of all structures lying lateral to the petrous segment of internal carotid artery) according to tumor size and location. Since the space between the V3 and TMJ is the main corridor of this approach, the key maneuver is the anterior translocation of V3 to obtain an acceptable surgical field.

Neuroendoscopic cysto-cisternostomy for middle cranial fossa arachnoid cysts: a systematic review of the practice principles from 169 cases.

INTRODUCTION: Arachnoid cysts are primarily dysembryogenetic splitting or duplication of the embryonic meningeal mesenchyme, hence the paediatric preponderance. Neuroendoscopic cysto-cisternostomy is now the favoured treatment option. We pooled data on middle fossa arachnoid cysts (MCFAC) demographics, clinical presentations, cyst characteristics, neuro-endoscopic cysto-cisternostomy and its outcomes. EVIDENCE ACQUISITION: Using search words (from the keywords; 'endoscopic treatment' and 'middle fossa arachnoid cysts') combined using Boolean operators, a systematic review of the PubMed and Cochrane CENTRAL was started on 1st February 2023, as per protocol (PROSPERO CRD42023394345); 65 records and then 46 reports were screened, 169 cases were pooled from the 19 recruited reports for the qualitative and quantitative syntheses, after methodological assessment (significantly excellent 57.9% quality) using the Joanna Briggs Institute critical appraisal tools. EVIDENCE SYNTHESIS: The male-to-female ratio was 2.4:1, with a weighted average-age of 11.25 years in the modal childhood (32.0%) age-group. Headaches (53/29.3%), seizures (30/16.6%) and macrocephaly (25/13.8%) were the commonest presentations. Right-sided (30/55.6%) and Galassi II (55/48.3%) and III (53/46.5%) lesions were common. Rigid (124/93.9%) endoscopes aided cysto-cisternostomy using mostly bipolar diathermy (31/43.7%) and ventriculostomy forceps (18/25.4%); creating one (22/18.3%), two (14/11.6%) or more (78/65.0%) stomas. Fenestration sites were specifically CNIII&ICA (32/25.8%), CNII&ICA (27/21.8%), CNIII&tentorium cerebelli (23/18.6%), CNIII&PCA (1/0.8%) and through the side of CNVI (1/0.8%) into the pre-pontine cistern. Good clinical and radiological outcomes were reported. CONCLUSIONS: Largely excellent-to-good quality, low-level evidence reported MCFACs presenting in childhood with headaches, seizures and macrocephaly. At least two fenestrations using bipolar-diathermy/forceps and balloon-catheter expansion were used for cysto-cisternostomy, with good outcomes.

Unusual anatomical detection of a third molar in the infratemporal fossa.

Third molar presence in the infratemporal fossa is a rare event and it has been reported previously only two times in the literature, except for the cases which arise from complications occurring during the extraction of the impacted upper third molar. Due to the presence of important vessel bundles and nerves in this area, third molar removal requires a correct surgical management in order to avoid many possible serious side effects. We report an unusual case of upper third molar detected in the infratemporal fossa, which has been thoroughly investigated radiologically and removed through a safe surgical approach.

Subtemporalis Muscle Middle Cranial Fossa Bone-Island Craniotomy Technique for Placement of an Active Transcutaneous Bone-Conduction Implant.

OBJECTIVE: Placement of an active transcutaneous bone-conduction implant (BCI) requires drilling of a precise bone bed to accommodate the device and allow for fixation points to make appropriate contact with bone, which can be difficult even when lifts are used. We describe a subtemporalis muscle middle cranial fossa bone-island craniotomy technique that simplifies the procedure and obviates the need for lifts in securing the device. STUDY DESIGN: Prospective case series. SETTING: Tertiary academic medical center. PATIENTS: Seventeen patients underwent surgery for placement of 18 transcutaneous BCIs, 14 for conductive or mixed hearing loss, and 4 for single-sided deafness. INTERVENTIONS: Surgical placement of a transcutaneous BCI with a bone-island craniotomy technique. MAIN OUTCOME MEASURES: Functional gain in air-conduction thresholds, aided air-bone gap, frequency of need for lifts, and minor and major complications. RESULTS: For the conductive or mixed hearing loss cohort, with the transcutaneous BCI in place, there was a highly statistically significant mean functional gain of 35.4 dB hearing level (HL) (range, 16.7-50.25 dB HL; standard deviation, 12.4 dB HL) compared with the unaided condition (p < 0.0001; 95% confidence interval, 36.6-51.6 dB HL). Lifts were not needed in any case. There was one minor complication requiring a second procedure in a patient who had previously received radiation and no major complications. There was no device loss or failure. CONCLUSIONS: A subtemporalis muscle middle cranial fossa bone-island craniotomy technique eliminates the need for lifts and is a safe and effective method for placement of a transcutaneous BCI.

Analysis of hearing preservation and facial nerve function for patients undergoing vestibular schwannoma surgery: the middle cranial fossa approach versus the retrosigmoid approach--personal experience and literature review.

OBJECTIVE: To compare hearing preservation and facial nerve function outcomes in patients undergoing vestibular schwannoma surgery performed using either the middle cranial fossa approach (MCFA) or the retrosigmoid approach (RSA). MATERIALS AND METHODS: A review of the medical records of patients diagnosed with vestibular schwannoma who underwent surgical tumor removal in a single reference center via the MCFA or the RSA between January 1988 and December 2008 was conducted. RESULTS: During this period, 90 patients underwent surgery via the MCFA while 86 patients received surgical treatment via the RSA. Of the patients subjected to the MCFA, 80.7% were characterized by a House-Brackmann (HB) grade I or II outcome, whereas 96.5% of patients undergoing the RSA were characterized by a HB grade I or II outcome (p = 0.001). This difference appeared only for extrameatal tumors when we compared size-matched tumors (58.3% MCFA vs. 98% RSA; p = 0.0006). There was no statistically significant difference in the hearing outcomes upon consideration of hearing preservation as characterized by the modified Sanna classification system involving classes A and B (18.9% MCFA vs. 10.6% RSA; p = 0.122). CONCLUSION: No statistically significant difference in hearing preservation was identified when comparing tumors operated upon via the MCFA versus the RSA. However, our results indicate that a higher risk of facial nerve function impairment exists if the surgery is performed via the MCFA under circumstances where the tumor extends to the cerebellopontine angle.

Extended Middle Cranial Fossa Approach for Placement of Auditory Brainstem Implants.

OBJECTIVE: Traditionally, auditory brainstem implants (ABIs) have been placed via the translabyrinthine or retrosigmoid approaches. In select patients, a modified extended middle cranial fossa (xMCF) approach with tentorial ligation may be advantageous for vestibular schwannoma (VS) resection and auditory rehabilitation. This manuscript describes the application of this modification of the MCF approach for simultaneous VS resection and ABI placement. PATIENTS: Patients with neurofibromatosis type 2, profound bilateral sensorineural hearing loss, single functioning sigmoid/jugular venous system, and giant (>4 cm) VS. INTERVENTIONS: Simultaneous VS resection and ABI placement via a modified xMCF approach with tentorial ligation. MAIN OUTCOME MEASURES: Extent of tumor removal and brainstem decompression, access to lateral recess of the fourth ventricle, functional hearing improvement, surgical complications. RESULTS: Two patients met indications and underwent surgery. There were no immediate or delayed surgical complications. Both had subtotal tumor removal with significant decompression of the brainstem and ABI placement. One patient achieved voice and environmental sound awareness at 35 to 55 dbHL across frequencies. The second patient presented with failure to thrive and multiple lower cranial neuropathies in addition to the above-listed indications. She was hospitalized multiple times after surgery due to failure to thrive and recurrent aspiration pneumonia. Her device was never activated, and she expired 1 year after surgery. CONCLUSIONS: The xMCF with tentorial ligation is an additional approach for tumor resection and ABI placement in selected patients with neurofibromatosis type 2. Future studies will further define when this approach is most applicable as well as the challenges and pitfalls.

Retro-odontoid Pseudotumor: Two Cases of Intradural Ganglion Cysts Arising From the Odontoid Process with Syringobulbia.

BACKGROUND: Ganglion cysts mostly occur in the knuckles and wrists, but they rarely present in the odontoid process and can cause neurological symptoms by compressing the spinal cord. They are mostly localized in the epidural space, but may very rarely appear in the intradural space. There are no reports of cases of intradural ganglion cyst involving syringobulbia. CASE DESCRIPTION: We report the presentation and management of 2 cases of an intradural ganglion cyst of the odontoid process. Several treatment options for ganglion cysts of the odontoid process have been reported, such as rest and use of a neck collar, posterior decompression and fusion, and transoral anterior decompression. Because our 2 cases progressed rapidly and had severe neurological symptoms, surgical treatment was performed for rapid decompression and definitive pathological diagnosis. The mass was resected as much as possible using the lateral occipital fossa approach, and the operation was completed without dissection of the brain stem or manipulation of the syringobulbia. Postoperatively, neurological symptoms promptly improved, and the syringobulbia reduced. CONCLUSIONS: For intradural ganglion cysts with syringobulbia, we suggest relief of the compression by resection of the mass and treatment of the syringobulbia in 2 stages, if necessary, to avoid the risk of damage to the brainstem.

Paediatric Bonebridge: bilateral simultaneous asymmetrical implantation.

BACKGROUND: The Bonebridge is an active transcutaneous bone conduction implant recommended as a surgical option for adults and children (aged 5-18 years). Successful implantation of the Bonebridge is often restricted by an insufficient amount of temporal bone to house the transducer in the paediatric patient. METHOD AND RESULTS: In this unique paediatric case, bilateral Bonebridge devices were implanted simultaneously in the right sinodural angle and the left middle cranial fossa. CONCLUSION: The simultaneous implantation of bilateral Bonebridge devices was well tolerated in this paediatric patient, with significant improvement in her hearing. The middle cranial fossa is a viable option for housing the transducer.

Pure Endoscopic Surgery via Subtemporal Extradural Keyhole Approach for Middle Cranial Fossa Tumors.

OBJECTIVE: Extradural subtemporal keyhole approach could provide adequate removal for some specific middle skull base tumors. The combination of endoscopy and keyhole technique might further help to minimize the complications and provide optimal surgical visualization. Here, a series of attempts with endoscopy by mini-invasive subtemporal extradural approach for 5 middle skull base tumors were successfully achieved. METHODS: From November 2015 to November 2018, resections of 5 cases of middle cranial fossa tumors were performed with pure endoscopy via subtemporal extradural keyhole approach. Patient medical records, imaging data, surgical procedures, pathology results, and follow-up outcomes were collected and analyzed. RESULTS: Adequate extradural subtemporal space was successfully established for endoscopy, and tumor resection was performed. Postoperative pathology confirmed cholesteatoma, cholesterol granuloma, schwannoma, granuloma, and osteoblastoma, respectively. Two patients with osteoblastoma and granuloma received subtotal resection, and the other 3 achieved total resection. One patient suffered from brain edema and was relieved after systematic mannitol treatment. No other complications were observed, and no progression was found during follow-up. CONCLUSIONS: This exploratory series demonstrated the safety and effectiveness of pure endoscopic surgery via subtemporal extradural route for satisfactory middle cranial base tumor resection.

Transnasal transpterygoid resection of meningoencephalocoele with abolition of seizures.

Meningoencephalocoeles are herniations of intracranial contents through skull base defects. Patients may present with a plethora of symptoms ranging from cerebrospinal fluid (CSF) rhinorrhoea to epileptic convulsions, or indeed may be asymptomatic. We present a case of a 24-year-old man suffering from new onset, drug-resistant tonic-clonic seizures. Imaging studies revealed neural tissue and meninges protruding through the pterygoid portion of the sphenoid bone, into the anteromedial aspect of the middle cranial fossa. An image-guided endoscopic transnasal transpterygoid approach was carried out as a joint otolaryngological and neurosurgical procedure, resulting in the patient being seizure-free for over 12 months postoperatively. There is a paucity of literature supporting such an endoscopic approach to treat epilepsy secondary to a meningoencephalocoele. We illustrate that this is a safe and minimally invasive treatment option which ultimately rendered the patient free of all anticonvulsants.

Synovial chondromatosis of the temporomandibular joint with glenoid fossa erosion: Disk preservation for spontaneous anatomical recovery.

Synovial chondromatosis (SC) of the temporomandibular joint is a pseudoneoplastic condition characterized by benign cartilaginous metaplasia of synovial tissue mesenchymal residues with intra-articular nodule formation. TMJ involvement is rare. Interposition of loose bodies in the articular space can generate pressure, leading to glenoid fossa erosion with intracranial extension. The aim of this study was to present six SC cases with intracranial extension treated using a surgical procedure. All the patients were treated with open surgery. The superior compartment of the TMJ was opened widely to carefully remove the metaplasic mass. Temporal synovectomy was then performed. Attention was paid to preserving the integrity of the articular disc. The exposed dura mater was also preserved. No material was used to reconstruct the gap in the glenoid fossa. A 1-year follow-up showed no swelling or pain. Patients demonstrated good recovery of mouth opening, with improvement over previous mouth limitations. Morphological studies, performed using MRI and CT, showed complete anatomical recovery of the TMJ and total bone reconstruction of the glenoid fossa. Simple removal of intra-articular nodules, with TMJ arthroplasty and articular disk preservation, represents an efficient treatment option for full anatomical and functional recovery in synovial chondromatosis of the temporomandibular joint with glenoid fossa erosion of less than 1 cm2.

Endoscopic Transcanal Approach to Geniculate Ganglion Hemangioma and Simultaneous Facial Nerve Reinnervation: A Case Report.

Hemangioma of the facial nerve (FN) is a very rare benign tumor whose origin is the vascular plexi that surround the nerve. The transpetrous, retrosigmoid, and middle cranial fossa (MCF) routes are the traditional and most widely used approaches to reach these lateral skull base neoformations. However, this very complex region can be reached through an exclusive transcanal endoscopic procedure in selected cases. One of these was a 42-year-old patient who had been presenting a worsening left FN paralysis (grade VI according to the House-Brackmann scale at the time of visit) for 22 months without a history of trauma or infection. Radiological studies showed a lesion in the region of the geniculate ganglion. A suprageniculate endoscopic approach was performed to remove the lesion, with the sacrifice of the FN and a simultaneous hypoglossal-facial anastomosis. The aim of this minimally invasive surgery is the complete excision of the disease, maintaining the hearing function intact and restoration of facial function, whenever possible, avoiding more invasive approaches.

Blister-like aneurysms of the supraclinoid internal carotid artery: challenging endovascular treatment with stent-assisted coiling.

''Blister-like'' aneurysms of the supraclinoid segment of the internal carotid artery are usually small and have fragile walls, necessitating special care to prevent rebleeding. These lesions are considered high-risk aneurysms because of the technical difficulties associated with their surgical and endovascular treatment. In this report, we describe the use of stent-assisted, repeated coil embolization in the treatment of a ruptured blister-like aneurysm that experienced rapid growth. Stent-assisted coil embolization is an alternative, but sometimes hazardous, treatment for select blister-like aneurysms. Careful serial follow-up angiography will provide documentation as to the long-term stability of the endovascularly treated blister-like aneurysm described here, but early results are encouraging. Alternatively, placement of telescoped stents or graft-stent devices offers promise for future endovascular therapy.

Comparative study on two surgical procedures for middle cranial fossa arachnoid cysts.

In this study, we explored the operation options for middle cranial fossa arachnoid cysts (MCFAC). One hundred and forty-nine patients who were operated for a symptomatic MCFAC between 1993 and 2006 in our hosptial were analyzed. Follow-up time ranged from 1 y to 14 y (mean=5.4 y). All these patients were divided into three subgroups according to Galassi classification. Long-term outcome and complications were studied respectively. Fenestration (F) resulted in a more favorable long-term outcome and less complication for cysts of types I and II, whereas a favorable outcome was noted in type III patients who underwent cysto-peritoneal shunting (S). We are led to conclude that Fenestration is suitable for cysts of types I and II (Galassi classification), cysto-peritoneal shunting is better for cysts of type III.

Comprehensive review of the extended middle cranial fossa approach.

PURPOSE OF REVIEW: To review the current literature on the extended middle cranial fossa (xMCF) approach and to provide a comprehensive description of the relevant anatomy, indications, surgical technique, results, and complications. RECENT FINDINGS: The xMCF approach expands the surgical exposure provided by the sMCF approach, allowing access to the internal auditory canal, cerebellopontine angle, prepontine cistern, anterior petrous apex, petrous carotid artery, Meckel's cave, cavernous sinus, mid and upper clivus, and posterior lesions approaching the jugular foramen. Preservation of serviceable hearing is possible with success rates approximating 50% in vestibular schwannoma and meningioma resection, and facial nerve outcome is excellent. SUMMARY: The xMCF is an important approach for difficult to access lesions that additionally offers the possibility of hearing preservation. This approach is also useful for vascular lesions, auditory brainstem implantation, and lesions of mid-brainstem.

Repair of Tegmen Tympani Defect Presenting with Spontaneous Cerebrospinal Fluid Otorrhea Using the Middle Cranial Fossa Approach.

Spontaneous cerebrospinal fluid (CSF) otorrhea frequently occurs without temporal bone trauma, fracture, surgery, or any identifiable causes. It is usually associated with tegmen tympani defects of the temporal bone in adults. The congenital origin theory and the arachnoid granulation theory have been accepted to explain the tegmen tympani defect. Magnetic resonance imaging (MRI) and computed tomography (CT) are used to show the defects, brain tissue, and the meninges. We recently encountered three cases of spontaneous CSF otorrhea with a defect on the tegmental plate of the temporal bone. High-resolution CT (HRCT) scan of the temporal bones showed the tegmen tympani defects. The defects were successfully repaired with temporal muscle fascia or fascia lata graft and fibrin glue using the middle cranial fossa approach via craniotomy.