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.

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.

scholarly journals Gamma Knife radiosurgery for facial nerve schwannomas: a multicenter study

2015 ◽  
Vol 123 (2) ◽  
pp. 387-394 ◽  
Author(s):  
Jason P. Sheehan ◽  
Hideyuki Kano ◽  
Zhiyuan Xu ◽  
Veronica Chiang ◽  
David Mathieu ◽  
...  
Keyword(s):  
Facial Nerve ◽  
Stereotactic Radiosurgery ◽  
Gamma Knife ◽  
Gamma Knife Radiosurgery ◽  
Rank Test ◽  
Tumor Control ◽  
Nerve Function ◽  
Facial Nerve Function ◽  
Log Rank Test

OBJECT Facial nerve schwannomas (FNSs) are rare intracranial tumors, and the optimal management of these tumors remains unclear. Resection can be undertaken, but the tumor’s intimate association with the facial nerve makes resection with neurological preservation quite challenging. Stereotactic radiosurgery (SRS) has been used to treat FNSs, and this study evaluates the outcome of this approach. METHODS At 8 medical centers participating in the North American Gamma Knife Consortium (NAGKC), 42 patients undergoing SRS for an FNS were identified, and clinical and radiographic data were obtained for these cases. Males outnumbered females at a ratio of 1.2:1, and the patients’ median age was 48 years (range 11–76 years). Prior resection was performed in 36% of cases. The mean tumor volume was 1.8 cm3, and a mean margin dose of 12.5 Gy (range 11–15 Gy) was delivered to the tumor. RESULTS At a median follow-up of 28 months, tumor control was achieved in 36 (90%) of the 40 patients with reliable radiographic follow-up. Actuarial tumor control was 97%, 97%, 97%, and 90% at 1, 2, 3, and 5 years postradiosurgery. Preoperative facial nerve function was preserved in 38 of 42 patients, with 60% of evaluable patients having House-Brackmann scores of 1 or 2 at last follow-up. Treated patients with a House-Brackmann score of 1 to 3 were more likely to demonstrate this level of facial nerve function at last evaluation (OR 6.09, 95% CI 1.7–22.0, p = 0.006). Avoidance of temporary or permanent neurological symptoms was more likely to be achieved in patients who received a tumor margin dose of 12.5 Gy or less (log-rank test, p = 0.024) delivered to a tumor of ≤ 1 cm3 in volume (log-rank test, p = 0.01). CONCLUSIONS Stereotactic radiosurgery resulted in tumor control and neurological preservation in most FNS patients. When the tumor is smaller and the patient exhibits favorable normal facial nerve function, SRS portends a better result. The authors believe that early, upfront SRS may be the treatment of choice for small FNSs, but it is an effective salvage treatment for residual/recurrent tumor that remain or progress after resection.

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.

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.

scholarly journals Is Salvage Surgery for Large Vestibular Schwannomas After Failed Gamma-knife Radiosurgery More Challenging?

2021 ◽  
Author(s):  
Lucas Troude ◽  
Mohamed Boucekine ◽  
Anne Balossier ◽  
Guillaume Baucher ◽  
Jean-Pierre Lavieille ◽  
...  
Keyword(s):  
Facial Nerve ◽  
Gamma Knife ◽  
Salvage Surgery ◽  
Gamma Knife Radiosurgery ◽  
Tumor Control ◽  
Nerve Sparing ◽  
Nerve Function ◽  
Facial Nerve Function ◽  
Failure Group

Abstract Objectives: In order to verify whether a previous Gamma-Knife surgery (GKS) treatment could influence the oncological and functional outcome in large vestibular schwannoma (VS) surgery, we have compared group of patients operated on for large VS after failed-GKS to a group of genuine VS that underwent the same functional nerve-sparing resection technique regimen in the same period.Methods: Single center retrospective cohort study of 23 consecutive GKS-failure and 170 genuine VS patients operated on between April 2003 and March 2019. After resection, patients were allocated to a Wait-&-rescan or an upfront GKS policy.Results: At last follow-up examination, the facial nerve function was good (House-Brackmann Grades I or II) in 95% of the GKS-failure and 84% of the genuine VS patients (p=.25). The median volume of tumor residue was .56cc in the GKS-failure group, and .62cc in the genuine VS group (p=.70). Tumor control was achieved in 91% and 83% of cases with a mean follow-up of 74 and 63 months in the GKS-failure and the genuine VS populations, respectively. The 1-, 5- and 7-year progression free survival were 100%, 95% & 85% respectively in the GKS-failure group, and 97%, 80% & 81% in the genuine VS group (p=.27).Conclusion: Despite significant modifications of the microsurgical environment associated to salvage surgery after GKS-failure, a functional nerve-sparing resection is an effective strategy to optimize the results on facial nerve function, with similar long-term tumor control to those observed in the genuine VS population.

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.

Gamma knife radiosurgery as a single treatment modality for large cerebral arteriovenous malformations

2000 ◽  
Vol 93 (supplement_3) ◽  
pp. 113-119 ◽  
Author(s):  
D. Hung-Chi Pan ◽  
Wan-Yuo Guo ◽  
Wen-Yuh Chung ◽  
Cheng-Ying Shiau ◽  
Yue-Cune Chang ◽  
...  
Keyword(s):  
Gamma Knife ◽  
Arteriovenous Malformations ◽  
Radiation Treatment ◽  
Gamma Knife Radiosurgery ◽  
Consecutive Series ◽  
Content Type ◽  
Obliteration Rate ◽  
Complete Obliteration ◽  
Fine Print

Object. A consecutive series of 240 patients with arteriovenous malformations (AVMs) treated by gamma knife radiosurgery (GKS) between March 1993 and March 1999 was evaluated to assess the efficacy and safety of radiosurgery for cerebral AVMs larger than 10 cm3 in volume. Methods. Seventy-six patients (32%) had AVM nidus volumes of more than 10 cm3. During radiosurgery, targeting and delineation of AVM nidi were based on integrated stereotactic magnetic resonance (MR) imaging and x-ray angiography. The radiation treatment was performed using multiple small isocenters to improve conformity of the treatment volume. The mean dose inside the nidus was kept between 20 Gy and 24 Gy. The margin dose ranged between 15 to 18 Gy placed at the 55 to 60% isodose centers. Follow up ranged from 12 to 73 months. There was complete obliteration in 24 patients with an AVM volume of more than 10 cm3 and in 91 patients with an AVM volume of less than 10 cm3. The latency for complete obliteration in larger-volume AVMs was significantly longer. In Kaplan—Meier analysis, the complete obliteration rate in 40 months was 77% in AVMs with volumes between 10 to 15 cm3, as compared with 25% for AVMs with a volume of more than 15 cm3. In the latter, the obliteration rate had increased to 58% at 50 months. The follow-up MR images revealed that large-volume AVMs had higher incidences of postradiosurgical edema, petechiae, and hemorrhage. The bleeding rate before cure was 9.2% (seven of 76) for AVMs with a volume exceeding 10 cm3, and 1.8% (three of 164) for AVMs with a volume less than 10 cm3. Although focal edema was more frequently found in large AVMs, most of the cases were reversible. Permanent neurological complications were found in 3.9% (three of 76) of the patients with an AVM volume of more than 10 cm3, 3.8% (three of 80) of those with AVM volume of 3 to 10 cm3, and 2.4% (two of 84) of those with an AVM volume less than 3 cm3. These differences in complications rate were not significant. Conclusions. Recent improvement of radiosurgery in conjunction with stereotactic MR targeting and multiplanar dose planning has permitted the treatment of larger AVMs. It is suggested that gamma knife radiosurgery is effective for treating AVMs as large as 30 cm3 in volume with an acceptable risk.

Factors related to complete occlusion of arteriovenous malformations after gamma knife radiosurgery

2000 ◽  
Vol 93 (supplement_3) ◽  
pp. 96-101 ◽  
Author(s):  
Jong Hee Chang ◽  
Jin Woo Chang ◽  
Yong Gou Park ◽  
Sang Sup Chung
Keyword(s):  
Gamma Knife ◽  
Arteriovenous Malformations ◽  
Gamma Knife Radiosurgery ◽  
Maximum Diameter ◽  
Content Type ◽  
Complete Occlusion ◽  
Factors Associated ◽  
Martin Grade ◽  
Fine Print

Object. The authors sought to evaluate the effects of gamma knife radiosurgery (GKS) on cerebral arteriovenous malformations (AVMs) and the factors associated with complete occlusion. Methods. A total of 301 radiosurgical procedures for 277 cerebral AVMs were performed between December 1988 and December 1999. Two hundred seventy-eight lesions in 254 patients who were treated with GKS from May 1992 to December 1999 were analyzed. Several clinical and radiological parameters were evaluated. Conclusions. The total obliteration rate for the cases with an adequate radiological follow up of more than 2 years was 78.9%. In multivariate analysis, maximum diameter, angiographically delineated shape of the AVM nidus, and the number of draining veins significantly influenced the result of radiosurgery. In addition, margin radiation dose, Spetzler—Martin grade, and the flow pattern of the AVM nidus also had some influence on the outcome. In addition to the size, topography, and radiosurgical parameters of AVMs, it would seem to be necessary to consider the angioarchitectural and hemodynamic aspects to select proper candidates for radiosurgery.

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