Preservation of facial function during removal of acoustic neuromas

1984 ◽  
Vol 61 (4) ◽  
pp. 757-760 ◽  
Author(s):  
Aage R. Møller ◽  
Peter J. Jannetta
Keyword(s):  
Facial Nerve ◽  
Nerve Function ◽  
Facial Nerve Function ◽  
Content Type ◽  
Acoustic Neuromas ◽  
Internal Impedance ◽  
Monopolar Stimulation ◽  
Stimulation Technique ◽  
Facial Function ◽  
Fine Print

✓ The authors describe a modification in the way the facial nerve is stimulated electrically during operations to remove medium and large-sized (> 2 cm) acoustic tumors. This consists of monopolar stimulation with low internal impedance. Proper use of this modified stimulation technique together with acoustic monitoring of the electromyographic responses of facial muscles helps to preserve facial nerve function in patients undergoing these operations, and also decreases the duration of the operation.

The facial nerve in medial acoustic neuromas

2002 ◽  
Vol 97 (5) ◽  
pp. 1083-1090 ◽  
Author(s):  
Christian Strauss
Keyword(s):  
Facial Nerve ◽  
Preoperative Evaluation ◽  
Internal Auditory Canal ◽  
Functional Results ◽  
Consecutive Series ◽  
Nerve Function ◽  
Facial Nerve Function ◽  
Content Type ◽  
Acoustic Neuromas ◽  
Fine Print

Object. Functional results after surgery for acoustic neuromas that have little or no growth within the internal auditory canal are controversial, because these medial tumors can grow to a considerable size within the cerebellopontine angle (CPA) before symptoms occur. Methods. A prospective study was designed to evaluate the surgical implications of the course of the facial nerve within the CPA on medial acoustic neuromas. This study included a consecutive series of 22 patients with medial acoustic neuromas (mean size 32 mm, range 17–52 mm) who underwent surgery via a suboccipitolateral approach between 1997 and 2001. All patients underwent pre- and postoperative magnetic resonance imaging and preoperative electromyography (EMG). Evaluation was based on continuous intraoperative EMG monitoring and video recordings of the procedure. All patients were reevaluated at a mean of 19 months (6–50 months) postsurgery. Preoperative evaluation of facial nerve function revealed House—Brackmann Grade I in six, Grade II in 14, and Grade III in two patients. During surgery a distinct splitting of the nerve at the root exit zone through its intracisternal course was seen in eight patients and documented by selective electrical stimulation. The facial nerve was separated into a smaller portion that ran cranially and parallel to the trigeminal nerve, and a larger portion on the anterior tumor surface. Both components joined anterior to the porus without major spreading of the nerve bundle. In two cases the nerve was found on the posterior surface of the cranial tumor. In one case the facial nerve entered the porus of the canal at its lower part, obtaining the expected anatomical position proximally within the middle portion of the canal. An anterior cranial, middle (five cases each), or caudal course (two cases) was seen in the remaining patients. After surgery, facial nerve function deteriorated in most cases; on follow-up evaluation House—Brackmann Grade I was found in 11, Grades II and III in 10, and Grade V in one patient. Conclusions. The facial nerve requires special attention in surgery for medial acoustic neuromas, because an atypical course of the nerve can be expected in the majority of cases. A split course of the nerve was found in 36% of the cases presented. Meticulous use of intraoperative facial nerve stimulation and continuous monitoring ensures facial nerve integrity and offers good functional results in patients with medial acoustic neuromas.

Medial acoustic neuromas: clinical and surgical implications

2014 ◽  
Vol 120 (5) ◽  
pp. 1095-1104 ◽  
Author(s):  
Ian F. Dunn ◽  
Wenya Linda Bi ◽  
Kadir Erkmen ◽  
Paulo A. S. Kadri ◽  
David Hasan ◽  
...  
Keyword(s):  
Facial Nerve ◽  
Hearing Preservation ◽  
Growth Patterns ◽  
Maximum Diameter ◽  
Nerve Function ◽  
Facial Nerve Function ◽  
Class A ◽  
Acoustic Neuromas ◽  
Facial Function

Object Medial acoustic neuroma is a rare entity that confers a distinct clinical syndrome. It is scarcely discussed in the literature and is associated with adverse features. This study evaluates the clinical and imaging features, pertinent surgical challenges, and treatment outcome in a large series of this variant. The authors postulate that the particular pathological anatomy with its arachnoidal rearrangement has a profound implication on the surgical technique and outcome. Methods The authors conducted a retrospective analysis of 52 cases involving 33 women and 19 men who underwent resection of medial acoustic neuromas performed by the senior author (O.A.) over a 20-year period (1993–2013). Clinical, radiological, and operative records were reviewed, with a specific focus on the neurological outcomes and facial nerve function and hearing preservation. Intraoperative findings were analyzed with respect to the effect of arachnoidal arrangement on the surgeon's ability to resect the lesion and the impact on postoperative function. Results The average tumor size was 34.5 mm (maximum diameter), with over 90% of tumors being 25 mm or larger and 71% being cystic. Cerebellar, trigeminal nerve, and facial nerve dysfunction were common preoperative findings. Hydrocephalus was present in 11 patients. Distinguishing intraoperative findings included marked tumor adherence to the brainstem and frequent hypervascularity, which prompted intracapsular dissection resulting in enhancement on postoperative MRI in 18 cases, with only 3 demonstrating growth on follow-up. There was no mortality or major postoperative neurological deficit. Cerebrospinal fluid leak was encountered in 7 patients, with 4 requiring surgical repair. Among 45 patients who had intact preoperative facial function, only 1 had permanent facial nerve paralysis on extended follow-up. Of the patients with preoperative Grade I–II facial function, 87% continued to have Grade I–II function on follow-up. Of 10 patients who had Class A hearing preoperatively, 5 continued to have Class A or B hearing after surgery. Conclusions Medial acoustic neuromas represent a rare subgroup whose site of origin and growth patterns produce a distinct clinical presentation and present specific operative challenges. They reach giant size and are frequently cystic and hypervascular. Their origin and growth pattern lead to arachnoidal rearrangement with marked adherence against the brainstem, which is critical in the surgical management. Excellent surgical outcome is achievable with a high rate of facial nerve function and attainable hearing preservation. These results suggest that similar or better results may be achieved in less complex tumors.

Facial nerve injury in acoustic neuroma (vestibular schwannoma) surgery: etiology and prevention

1997 ◽  
Vol 87 (1) ◽  
pp. 60-66 ◽  
Author(s):  
Prakash Sampath ◽  
Michael J. Holliday ◽  
Henry Brem ◽  
John K. Niparko ◽  
Donlin M. Long
Keyword(s):  
Facial Nerve ◽  
Nerve Injury ◽  
Acoustic Neuroma ◽  
Facial Nerve Palsy ◽  
Nerve Function ◽  
Facial Nerve Function ◽  
Content Type ◽  
Facial Nerve Injury ◽  
Acoustic Neuroma Surgery ◽  
Fine Print

✓ Facial nerve injury associated with acoustic neuroma surgery has declined in incidence but remains a clinical concern. A retrospective analysis of 611 patients surgically treated for acoustic neuroma between 1973 and 1994 was undertaken to understand patterns of facial nerve injury more clearly and to identify factors that influence facial nerve outcome. Anatomical preservation of the facial nerve was achieved in 596 patients (97.5%). In the immediate postoperative period, 62.1% of patients displayed normal or near-normal facial nerve function (House—Brackmann Grade 1 or 2). This number rose to 85.3% of patients at 6 months after surgery and by 1 year, 89.7% of patients who had undergone acoustic neuroma surgery demonstrated normal or near-normal facial nerve function. The surgical approach appeared to have no effect on the incidence of facial nerve injury. Poor facial nerve outcome (House—Brackmann Grade 5 or 6) was seen in 1.58% of patients treated via the suboccipital approach and in 2.6% of patients treated via the translabyrinthine approach. When facial nerve outcome was examined with respect to tumor size, there clearly was an increased incidence of facial nerve palsy seen in the immediate postoperative period in cases of larger tumors: 60.8% of patients with tumors smaller than 2.5 cm had normal facial nerve function, whereas only 37.5% of patients with tumors larger than 4 cm had normal function. This difference was less pronounced, however, 6 months after surgery, when 92.1% of patients with tumors smaller than 2.5 cm had normal or near normal facial function, versus 75% of patients with tumors larger than 4 cm. The etiology of facial nerve injury is discussed with emphasis on the pathophysiology of facial nerve palsy. In addition, on the basis of the authors' experience with these complex tumors, techniques of preventing facial nerve injury are discussed.

Recording nasal muscle F waves and electromyographic activity of the facial muscles: a comparison of two methods used for intraoperative monitoring of facial nerve function

2001 ◽  
Vol 95 (6) ◽  
pp. 974-978 ◽  
Author(s):  
Christoph Wedekind ◽  
Norfrid Klug
Keyword(s):  
Facial Nerve ◽  
Electromyographic Activity ◽  
Nerve Function ◽  
Facial Nerve Function ◽  
Predictive Values ◽  
Content Type ◽  
Poor Outcome ◽  
Transient Loss ◽  
F Wave ◽  
Fine Print

Object. A comparison of two electrophysiological methods used to assess facial nerve function intraoperatively was conducted in 33 patients with tumors of the cerebellopontine angle. Methods. All 33 patients had presented with normal facial nerve function preoperatively. After general anesthesia had been induced by a mixture of midazolam and fentanyl, continual online EMG recordings from the orbicularis oculi and oris muscles were alternated with nasal muscle F-wave recordings. Facial nerve outcomes, assessed using a modified House—Brackmann scale, varied among good (48%), moderate (18%), and poor (33%). Analysis of electromyographic (EMG) data resulted in a significant correlation between the finding of only transient manipulation-evoked activity and a good outcome, whereas in cases in which there was poor outcome, an increase in the amplitude or duration of ongoing activity was detected. A permanent loss of nasal muscle F waves specifically appeared to indicate a severe dysfunction of the facial nerve that was linked to a poor outcome. All patients with latency and/or amplitude changes or even a transient loss of the F wave achieved good or moderate facial nerve outcomes. A transient loss of the F wave, however, was detected significantly more frequently in patients with moderate outcomes. None of these patients exhibited normal facial function (House—Brackmann Grade I) postoperatively. Conclusions. Online EMG monitoring can provide some information on imminent or even present damage to the facial nerve intraoperatively. The diagnostic sensitivity, specificity, and positive predictive values of a permanent F-wave loss, however, are much higher than those of EMG monitoring. Additionally, this loss of the F wave is supposed to be transient if the surgical procedure is stopped until the F wave recovers. Therefore, F-wave monitoring serves to alert the surgeon that the facial nerve is about to receive a lesion.

Hearing preservation in the removal of intracanalicular acoustic neuromas via the retrosigmoid approach

1997 ◽  
Vol 86 (3) ◽  
pp. 456-461 ◽  
Author(s):  
David W. Rowed ◽  
Julian M. Nedzelski
Keyword(s):  
Facial Nerve ◽  
Binaural Hearing ◽  
Retrosigmoid Approach ◽  
Nerve Function ◽  
Success Rates ◽  
Facial Nerve Function ◽  
Complete Excision ◽  
Hearing Conservation ◽  
Content Type ◽  
Acoustic Neuromas

✓ In a series of 514 consecutive operations for complete excision of acoustic neuromas, 94 procedures were performed via a retrosigmoid approach to preserve the patient's hearing. Twenty-six of these procedures (5.1%) were performed in cases of intracanalicular tumor and 68 (13.2%) were for larger lesions in which most of the tumor was located medial to the porus acusticus within the cerebellopontine angle. Preservation of useful hearing was achieved in 13 (50%) of 26 patients with intracanalicular tumors and in 20 (29%) of 68 with larger tumors. A trend toward higher success rates in intracanalicular tumors appears to be present, although the difference is not statistically significant (p = 0.09). Normal or nearnormal facial function (House and Brackmann Grades I and II) was present postoperatively in 25 (96%) of 26 patients. Indications for treatment of intracanalicular acoustic neuromas are considered and treatment alternatives are reviewed. Results from other series reporting removal of intracanalicular acoustic neuromas are considered with respect to hearing conservation and postoperative facial nerve function. Surgical excision of intracanalicular acoustic neuromas in otherwise healthy patients appears to be warranted if preservation of useful binaural hearing is considered a worthwhile objective and if perioperative morbidity can be maintained at an acceptably low level. The retrosigmoid approach is familiar to all neurosurgeons and offers a comparable success rate for hearing conservation and probably a superior outcome in terms of facial nerve function when compared with the middle fossa approach.

Immediate neurological deterioration after gamma knife radiosurgery for acoustic neuroma

2000 ◽  
Vol 93 (supplement_3) ◽  
pp. 78-81 ◽  
Author(s):  
Masao Tago ◽  
Atsuro Terahara ◽  
Keiichi Nakagawa ◽  
Yukimasa Aoki ◽  
Kuni Ohtomo ◽  
...  
Keyword(s):  
Facial Nerve ◽  
Gamma Knife ◽  
Acoustic Neuroma ◽  
Gamma Knife Radiosurgery ◽  
Neurofibromatosis Type ◽  
Nerve Function ◽  
Facial Nerve Function ◽  
Content Type ◽  
Acoustic Tumor ◽  
Fine Print

✓ The authors describe acute deterioration in facial and acoustic neuropathies following radiosurgery for acoustic neuromas. In May 1995, a 26-year-old man, who had no evidence of neurofibromatosis Type 2, was treated with gamma knife radiosurgery (GKS; maximum dose 20 Gy and margin dose 14 Gy) for a right-sided intracanalicular acoustic tumor. Two days after the treatment, he developed headache, vomiting, right-sided facial weakness, tinnitus, and right hearing loss. There was a deterioration of facial nerve function and hearing function from pretreatment values. The facial function worsened from House—Brackmann Grade 1 to 3. Hearing deteriorated from Grade 1 to 5. Magnetic resonance (MR) images, obtained at the same time revealed an obvious decrease in contrast enhancement of the tumor without any change in tumor size or peritumoral edema. Facial nerve function improved gradually and increased to House—Brackmann Grade 2 by 8 months post-GKS. The tumor has been unchanged in size for 5 years, and facial nerve function has also been maintained at Grade 2 with unchanged deafness. This is the first detailed report of immediate facial neuropathy after GKS for acoustic neuroma and MR imaging revealing early possibly toxic changes. Potential explanations for this phenomenon are presented.

Delayed facial palsy after resection of vestibular schwannoma

2002 ◽  
Vol 97 (1) ◽  
pp. 93-96 ◽  
Author(s):  
Gerald A. Grant ◽  
Robert R. Rostomily ◽  
D. Kyle Kim ◽  
Marc R. Mayberg ◽  
Donald Farrell ◽  
...  
Keyword(s):  
Facial Nerve ◽  
Vestibular Schwannoma ◽  
Facial Palsy ◽  
Tumor Resection ◽  
Consecutive Series ◽  
Tumor Diameter ◽  
Nerve Function ◽  
Facial Nerve Function ◽  
Content Type ◽  
Fine Print

Object. In this study the authors investigate delayed facial palsy (DFP), which is an underreported phenomenon after surgery for vestibular schwannoma (VS). The authors identified 15 (4.8%) patients from a consecutive series of 314 who underwent surgery for VS between 1988 and 2000, and in whom DFP developed. Delayed facial palsy was defined as a deterioration of facial nerve function from House—Brackmann Grades 1 or 2 more than 3 days postoperatively. Methods. All patients underwent intraoperative neurophysiological monitoring of facial nerve function. The average latency of DFP was 10.9 days (range 4–30 days). In six patients (40%) minor deterioration (≤ two House—Brackmann grades) had occurred at a mean of 10.2 days postsurgery, whereas in nine patients (60%) moderate deterioration (≥ three House—Brackmann grades) had occurred at a mean of 11.8 days postoperatively. Five (33%) of 15 patients recovered to Grade 1 of 2 function within 6 weeks of DFP onset. Of the 15 patients with DFP, 14 had completed 1 year of follow up at the time of this study. Twelve (80%) of these 15 patients recovered to Grade 1 or 2 function within 3 months, and 13 (93%) of 14 patients recovered within 1 year. In all cases, stimulation of the seventh cranial nerve on completion of tumor resection revealed the nerve to be intact, both anatomically and functionally, to proximal and distal stimulation at 0.1 mA. A smaller tumor diameter correlated with greater recovery of facial nerve function. There was no correlation between the latency or severity of or recovery from DFP, and the patient's age or sex, the surgical approach, frequency of neurotonic seventh nerve discharges, anatomical relationship of the facial nerve to the tumor, patient's history of tobacco use, or cardiovascular disease. Conclusions. It appears that DFP is an uncommon consequence of surgery for VS. Although excellent recovery of facial nerve function to its original postoperative status nearly always occurs after DFP, the magnitude and time course of the disorder were not predictors for subsequent recovery of facial nerve function.

Alternative to tarsorrhaphy in peripheral facial nerve palsy with expectation of functional recovery

1984 ◽  
Vol 61 (2) ◽  
pp. 405-406 ◽  
Author(s):  
Eduardo Fernandez ◽  
Roberto Pallini ◽  
Giulio Maira
Keyword(s):  
Facial Nerve ◽  
Functional Recovery ◽  
Nerve Palsy ◽  
Simple Technique ◽  
Facial Nerve Palsy ◽  
Nerve Function ◽  
Content Type ◽  
Peripheral Facial Nerve Palsy ◽  
Opening And Closing ◽  
Fine Print

✓ A simple technique is described for protecting the cornea in patients with peripheral facial nerve palsy while waiting for recovery of nerve function. The application of an adhesive strip to the superior eyelid permits opening and closing of the eye, and provides good protection of the cornea.

Facial nerve preservation during surgery for removal of acoustic nerve tumors

1982 ◽  
Vol 57 (6) ◽  
pp. 739-746 ◽  
Author(s):  
Richard H. Lye ◽  
John Dutton ◽  
Richard T. Ramsden ◽  
Joseph V. Occleshaw ◽  
Iain T. Ferguson ◽  
...  
Keyword(s):  
Facial Nerve ◽  
Petrous Bone ◽  
Ct Scans ◽  
Facial Weakness ◽  
Content Type ◽  
Nerve Preservation ◽  
Increased Risk ◽  
Acoustic Nerve ◽  
Facial Function ◽  
Fine Print

✓ A series of 33 patients with 35 acoustic nerve tumors is reviewed. Tumor size was estimated from computerized tomography (CT) scans, and its influence on anatomical and functional preservation of the facial nerve was assessed. Six tumors (one invading the petrous bone, three medium and two large tumors) were not detected on CT scans. The translabyrinthine approach was used in seven instances (one small and six medium tumors) and the suboccipital transmeatal approach for 28 tumors (seven medium and 21 large tumors). Anatomical preservation of the facial nerve was achieved in 83% of operations for tumor removal, two of which were subtotal. A further two patients underwent subtotal removal, but the facial nerve was destroyed. Large tumors carried an increased risk of damage to the facial nerve, but even in this group the nerve was preserved anatomically intact in 70% of cases. Damage to the facial nerve occurred more frequently in patients with preoperative evidence of facial weakness; however, this factor did not appear to influence functional recovery of the facial nerve, provided that the nerve was intact at the end of the operation. A simple grading system for facial nerve function is described. Only 76% of anatomically intact facial nerves showed any evidence of function 1 month after surgery. Postoperatively, facial function improved with time. At the latest review, 45% of these patients had normal facial function or mild facial weakness (Grades I and II).

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