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.

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.

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.

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.

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.

scholarly journals Delayed facial nerve palsy after vestibular schwannoma surgery

2018 ◽  
Vol 20 (1) ◽  
pp. 84-88
Author(s):  
Walter J. Fagundes Pereyra ◽  
Alonso Luis De Sousa ◽  
Karlo Faria Nunes ◽  
Deborah Nunes De Angeli
Keyword(s):  
Facial Nerve ◽  
Vestibular Schwannoma ◽  
Nerve Palsy ◽  
Facial Nerve Palsy ◽  
Surgical Removal ◽  
Electromyographic Activity ◽  
Immunological Study ◽  
Nerve Function ◽  
Facial Nerve Function ◽  
Nerve Dysfunction

Background: Facial nerve dysfunction may occur immediately after vestibular schwanoma surgery. Electromyographyc monitoring of motor cranial nerves during cerebellopontine angle surgery has become an essential tool. Although delayed onset of facial nerve dysfunction hours to months following vestibular schwanoma surgery are rare. Case description: We describe the case of a 70-years-old male who was admitted with a left side tinnitus and hearing loss of the last 3 years. Magnetic resonance imaging (MRI) T1-weighted demonstrated an isointensity lesion, 30mm in diameter, at the left cerebello-pontine angle with a small portion in the internal auditory canal. The patient was surgically treated by means of a standart suboccipital retrosigmoid approach. The facial nerve was monitored by continuously during surgery. Surgical removal was macroscopically complete. The facial nerve was well-preserved during surgery and showed at the end of the procedure normal electromyographic activity. The patient did well postoperatively and was discharged at the 4th postoperative day and facial function was normal (House-Brackmann grade I). On the 10th postoperative day he notices difficult closing his left eye that progressed to complete facial nerve palsy (House-Brackmann grade III). Steroid therapy was performed for five days associated with physical therapy. One month later his facial nerve function had completely recovered. After six months, the patient remains asymptomatic and neurologically intact. MRI obtained at the 16th postoperative day showed intense enhancement of the intracranial facial nerve segment and also demonstrated no residual tumor. Immunological study at the time of onset showed herpes simplex virus antibody titer normal as well as those for herpes zoster virus. Conclusions: Delayed facial nerve palsy remains an under reported and consequently not very known phenomenon in the neurosurgical practice and literature. Because of the 2009favorable rate of recovery, patients should be reassured in the interim and should not undergo any corrective surgical procedures to improve facial nerve function. Delayed facial nerve palsy is uncommon after vestibular schwannoma surgery. Excellent recovery of facial nerve function to the original postoperative status nearly always occurs in those circumstances.

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.

Neurotopographic considerations in the microsurgical treatment of small acoustic neurinomas

1998 ◽  
Vol 88 (3) ◽  
pp. 506-512 ◽  
Author(s):  
Wolfgang T. Koos ◽  
J. Diaz Day ◽  
Christian Matula ◽  
David I. Levy
Keyword(s):  
Facial Nerve ◽  
Hearing Preservation ◽  
Acoustic Neurinoma ◽  
Tumor Type ◽  
Nerve Function ◽  
Speech Discrimination ◽  
Content Type ◽  
Acoustic Neurinomas ◽  
Grade Ii ◽  
Fine Print

Object. The authors studied the relationships between tumor size, location, and topographic position relative to the intact facial nerve bundles in acoustic neurinomas to determine the influence of these factors on hearing preservation postoperatively. Consistent topographic relationships were found. Methods. Four hundred fifty-two patients with acoustic neurinoma treated via a retrosigmoid approach were analyzed with respect to hearing preservation and facial nerve function. One hundred fifteen tumors were identified as small and were categorized as Grades I and II. Patients with Grade I tumors, that is, purely intracanalicular lesions, all had good hearing preoperatively, defined by a less than 50-dB pure tone average and 50% speech discrimination score. All 14 Grade I tumors were removed, resulting in preservation of the patient's hearing by these criteria. There were no particular topographic anatomical relationships associated with these tumors that affected hearing preservation. Grade II tumors, defined as those protruding into the cerebellopontine angle without contacting the brainstem, were found in 101 patients and were divided by size into two grades: IIA (< 1 cm) and IIB (1–1.8 cm). In 90 patients with Grade IIA tumors, 72 (89%) of 81 who had preserved hearing preoperatively maintained it postoperatively, and in the 11 patients with Grade IIB tumors, six of whom had good hearing preoperatively, four (67%) had preserved hearing postoperatively. Six morphological types were identified based on their neurotopographic relationships to the elements of the vestibulocochlear nerve. Conclusions. Hearing preservation postsurgery by tumor type was as follows: 1A, 92%; 1B, 88%; 1C, 100%; 2A, 83%; 2B, 92%; and 3, 57%. Combined, this represents a hearing preservation rate of 87% after surgical treatment of Grade II acoustic neurinomas. Full nerve function was maintained in 88% of patients with anatomically preserved facial nerves in both Grade I and II tumors. The remaining 12% of patients retained partial function of the facial nerve. Two patients in the series lost anatomical integrity of the nerve due to surgery.

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