Surgical resection of vestibular schwannomas (VS) located within the internal auditory canal (IAC) is challenging, especially those located very laterally in the IAC. Various transcranial approaches ...have been described for resection of intracanalicular VS including retrosigmoid, translabyrinthine, and middle fossa approaches. Each approach has its indications, advantages, and limitations. The middle fossa approach (MFA) is considered by many authors as the gold standard approach for resection of small intracanalicular VS in young patients with serviceable hearing; however, there is often a limitation in complete visualization of the tumor.
The authors present an illustrative case to highlight the technical nuances of complementary use of endoscopy in MFA for complete resection of intracanalicular VS located at the IAC fundus, preserving preoperative hearing status and mainting intact facial nerve function.
In our experience, the combined use of the endoscope and the microspe as described here and illustrated in our case, improves visualization of the IAC and its contents, improving ressection and outcomes.
MFA allows for a direct yet safe surgical corridor to small intracanalicular VS. The implementation of endoscopy with MFA, especially for VS located laterally in the IAC, allows for better opportunity for complete resection of the tumor with improved preservation of hearing and facial nerve function.
•Surgical resection of vestibular schwannomas (VS) located within the internal auditory canal (IAC) is challenging.•MFA allows for a direct yet safe surgical corridor to small intracanalicular VS.•Implementation of endoscopy with MFA, especially for VS located laterally in the IAC, allows for complete resection.•Improved preservation of hearing and facial nerve function can result.
For hearing preservation in acoustic neuroma (AN) surgery, the middle fossa (MF) or retrosigmoid (RS) approach can be used. Recent literature advocates the use of the MF approach, especially for ...small ANs.
To present our critical analysis of operative results comparing these 2 approaches.
We reviewed 504 consecutive AN resections performed between November 1998 and September 2007 and identified 43 MF and 82 RS approaches for tumors smaller than 1.5 cm during hearing preservation surgery. Individual cases were examined postoperatively with respect to hearing ability, facial nerve activity, operative time, blood loss, and symptoms resulting from retraction of the cerebellar or temporal lobes.
Good hearing function (American Academy of Otolaryngology-Head and Neck Surgery class B or better) was preserved in 76.7% of patients undergoing surgery via the MF approach and in 73.2% of the RS group (P = .9024). Temporary facial nerve weakness was more frequent in the MF group (P = .0249). However, late (8-12 months) follow-up examinations showed good recovery in both groups. The mean operative time was 7.45 hours for the MF group and 5.2 hours for the RS group (P = .0318). The mean blood loss was 280.5 mL for the MF group and 80.8 mL for the RS group (P < .0001). Temporary symptoms of temporal lobe edema (drowsiness or speech disturbance) were noted in 6 MF cases. No cerebellar dysfunction was noted in the RS group.
Although hearing and facial nerve function assessed at approximately 1 year was similar with these 2 approaches, the RS approach provided several advantages over the MF approach for ANs smaller than 1.5 cm.
Objective: to evaluate recent contributions to the literature on prognostic factors of hearing preservation in small vestibular schwannoma microsurgery. Methods: review of the most recent studies. ...Results: factors such as tumor size, preoperative hearing status, tumor growth rate, tumor origin, surgical approach, radiological characteristics, results of preoperative neurophysiological tests, preoperative symptoms and demographic features have been investigated and some of them reported to be significant in the prediction of hearing preservation. Conclusions: tumor size and preoperative hearing status are the most impactful factors and play a key role in patient selection for hearing preservation surgery. Other features such as fundal extension, tumor origin and impaired ABR could have prognostic value on hearing preservation. Tumor growth rate, preoperative impedance, cVEMPs and age have also recently been found to be significant, but more studies are needed. The role of preoperative tinnitus, vertigo and gender is lacking and controversial, whereas the differences between available surgical approaches have been smoothed out in recent years.
The aim of this letter is to respond to a commentary on a published article on the middle fossa approach to BONEBRIDGE implantation with self-drilling screws published by the senior authors.
Conclusion: Middle fossa approach (MFA) shows a hearing preservation rate of 86% and facial nerve function was preserved with HB grade I or II in 93%. MFA is a good treatment option for ...intra-canalicular vestibular schwannomas when surgical excision is needed.
Background: Surgical outcomes of vestibular schwannoma have progressively improved with the advancement of microsurgical instruments. MFA is known to have better chances to preserve hearing, while it has limited access to the posterior fossa, limitation of tumor size, and higher risk of post-operative facial nerve weakness.
Objectives: To investigate surgical outcomes and clinical efficiency of MFA in vestibular schwannoma.
Methods: A retrospective study was done in 14 patients who underwent MFA for vestibular schwannoma in Asan Medical Center.
Results: The median age at diagnosis was 46.3 years. At initial presentation, 57% of the patients had vertigo, 43% hearing disturbance, and 64% tinnitus. The mean tumor size was 9.7 mm. The tumors were completely resected in 86% of the patients. Hearing was post-operatively preserved in 12 patients and two patients lost their hearing following surgery. Facial nerve function post-operatively remained unchanged in 12 patients (86%).
Objective To evaluate cochlear trauma after cochlear implant insertion through a middle fossa approach by means of histologic and imaging studies in temporal bones. Study Design Prospective cadaveric ...study. Setting University-based temporal bone laboratory. Subjects and Methods Twenty fresh-frozen temporal bones were implanted through a middle cranial fossa basal turn cochleostomy. Ten received a straight electrode and 10 a perimodiolar electrode. Samples were fixed in epoxy resin. Computed tomography (CT) scans determined direction, depth of insertion, and the cochleostomy to round window distance. The samples were polished by a microgrinding technique and microscopically visualized to evaluate intracochlear trauma. Descriptive and analytic statistics were performed to compare both groups. Results The CT scan showed intracochlear insertions in every bone, 10 directed to the middle/apical turn and 10 to the basal turn. In the straight electrode group, the average number of inserted electrodes was 12.3 vs 15.1 for the perimodiolar group ( U = 78, P = .0001). The median insertion depth was larger for the perimodiolar group (14.4 mm vs 12.5 mm, U = 66, P = .021). Only 1 nontraumatic insertion was achieved and 14 samples (70%) had important trauma (Eshraghi grades 3 and 4). No differences were identified comparing position or trauma grades for the 2 electrode models or when comparing trauma depending on the direction of insertion. Conclusion The surgical technique allows a proper intracochlear insertion, but it does not guarantee a correct scala tympani position and carries the risk of important trauma to cochlear microstructures.
The superior semicircular canal dehiscence syndrome (SCDS), which presents with comprehensive symptoms such as hyperacusis, autophony, and pressure-induced vertigo, has been recently recognized in ...Japan. Three patients with SCDS, in whom severe vestibular symptoms were unable to be controlled with conservative treatments, underwent capping surgery through the middle fossa approach. The preoperatively air-bone gap (AB gap) in the audiometry, the decreased threshold of cervical vestibular evoked myogenic potentials (cVEMP) and bone dehiscence of the superior semicircular canal could be observed in all patients on CT imaging. All patients suffered from positional vertigo for about one week after the operation. However, their cochlear and vestibular symptoms associated with the SCDS were relieved within a few months after the operation. The capping procedure decreased the AB gaps and increased the thresholds of cVEMP in all patients. We suggest that capping surgery via the middle fossa approach for the SCDS is an efficient procedure without severe side effects.
Revision Surgery for Vestibular Schwannomas Peng, Kevin A.; Chen, Brian S.; Lorenz, Mark B. ...
Journal of neurological surgery. Part B, Skull base,
12/2018, Letnik:
79, Številka:
6
Journal Article
Recenzirano
Odprti dostop
Abstract
Objectives
To describe clinical outcomes of patients undergoing revision surgery for vestibular schwannomas.
Design
Retrospective case series.
Setting
Tertiary private neurotologic ...practice.
Participants
Patients who underwent revision surgeries for recurrent/residual vestibular schwannomas between 1985 and 2015.
Main Outcome Measures
Degree of resection, facial nerve function, cerebrospinal fluid (CSF) leak.
Results
A total of 234 patients underwent 250 revision surgeries for recurrent/residual vestibular schwannomas. Of these, 86 carried a diagnosis of neurofibromatosis type 2 (NF2). The mean number of prior surgeries was 1.26, and 197 (85%) prior surgeries had been performed elsewhere. The average age at surgery was 43. The most common approach employed at the time of revision surgery was translabyrinthine (87%), followed by transcochlear (6%), middle fossa (5%), and retrosigmoid (2%). Gross total resection was achieved in 212 revision surgeries (85%). Preoperative House–Brackmann facial nerve function was similar in non-NF2 and NF2 groups (mean: 2.7). Mean postoperative facial nerve function at last follow-up was 3.8 in the non-NF2 group and 3.9 in the NF2 group. History of radiation and the extent of resection were not associated with differences in facial nerve function preoperatively or postoperatively. CSF leaks occurred after 21 surgeries (8%), and six (2%) patients required reoperation.
Conclusions
This is the largest series of revision surgery for vestibular schwannomas to date. Our preferred approach is the translabyrinthine craniotomy, which can be readily modified to include the transcochlear approach for improved access. CSF leak rate slightly exceeds that of primary surgery, and gross total resection is achievable in the vast majority of patients.
Controversy exists regarding the role of surgery for patients with skull base trauma and facial paralysis. Our goal is to report the long-term outcomes of early facial nerve decompression and repair ...via the middle fossa (MF) approach for patients with traumatic paralysis.
Retrospective case series.
Academic medical center.
There were 18 patients who met surgical criteria: immediate complete paralysis, greater than 90% degeneration on electroneurography (ENoG), and no voluntary electromyography (EMG) potentials within 14 days after trauma and 1 year minimum follow-up.
MF approach for traumatic facial paralysis and for irreversible injuries nerve grafting was performed.
Long-term facial function, hearing results, and surgical complications.
At MF decompression, 11 patients had an anatomically intact facial nerve. Of these patients with intact nerves, 72.7% obtained normal to near normal facial function (HB I or II) at 1 year: 27.3% to HB I, 45.5% to HB II, and 27.3% to HB III. At surgery, seven patients were found to have injuries that required nerve grafting and 100% improved to HB III. For all patients, facial nerve function significantly improved after surgery (p < 0.01). The average difference in pure tone average and word recognition after surgery was +2.9 dB and +3.3%, respectively (p = 0.44; p = 0.74). Minor, transient complications occurred in three patients and an abscess required drainage in one patient, but no other major complications.
In our series, all patients with traumatic complete paralysis and poor facial prognosis achieved a long-term outcome of HB III or better after MF approach for decompression and repair of the facial nerve.
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