Deterioration Of Facial Function Research Articles

Delayed facial palsy after resection of vestibular schwannoma: does it influence long-term facial nerve functional outcomes?

Delayed facial palsy (DFP) is a common and unique complication after resection of vestibular schwannoma (VS). Few studies have focused on the clinical question of whether patients with DFP can be expected to have the same long-term prognosis in terms of facial nerve function as those without DFP based on their facial nerve function immediately postoperatively. This study aimed to clarify the clinical impact of DFP on the long-term functional status of the facial nerve after VS resection. The authors retrospectively reviewed patients with sporadic VS who were treated surgically via a retrosigmoid approach between January 2002 and March 2020. DFP was defined as de novo deterioration of facial nerve function by a House-Brackmann (HB) grade ≥ I more than 72 hours postoperatively. The incidence of DFP after VS resection and its impact on long-term facial nerve function were analyzed. DFP developed in 38 (14.3%) of 266 patients who met the inclusion criteria. The median latency until DFP onset postoperatively was 8.5 days. When facial nerve function was normal immediately postoperatively, the rate of preservation of favorable facial nerve function (HB grade I or II) at 24 months postoperatively was 100% for all patients regardless of whether they developed DFP. In contrast, when facial nerve dysfunction was present immediately postoperatively, the rate of preservation of favorable facial nerve function at 24 months postoperatively was significantly lower in patients with DFP than in those without DFP (77.8% vs 100% in patients with HB grade II immediately postoperatively, p = 0.001; 50.0% vs 90.3% in those with HB grade III immediately postoperatively, p = 0.042). DFP development had a significantly negative impact on the long-term functional status of the facial nerve postoperatively when age, tumor size, and HB grade immediately postoperatively were taken into account (OR 0.04, 95% CI 0.01-0.20; p < 0.001). DFP can be a minor complication when normal facial nerve function is observed immediately after surgery. However, when facial nerve dysfunction is present immediately after surgery, even if mild, the long-term prognosis for facial nerve function is significantly worse in patients with DFP than in those without DFP.

«Burr hole» microsurgery for vestibular schwannoma

To evaluate the efficacy and safety of minimally invasive «burr hole» microsurgery for vestibular schwannoma. A retrospective analysis of postoperative outcomes in 50 consecutive patients with vestibular schwannoma was performed. All patients underwent burr hole microsurgery between 2016 and 2020. All patients satisfactorily tolerated surgical treatment. Total resection was carried out in 21 (42%) cases, almost total resection - in 21 (42%) patients (>95% of baseline volume). Subtotal resection was performed in 8 (16%) cases. Mean surgery time was 132 min (range 60-340). Postoperative deterioration of facial nerve function occurred in 20 (40%) patients. Severe dysfunction (House-Brackmann grade V-VI) was observed only in three patients. Other 17 patients had moderate dysfunction of the facial nerve (House-Brackmann grade III-IV). Useful hearing was preserved in 6 (50%) out of 12 patients with preoperative useful hearing. Minimally invasive burr hole microsurgery is an effective method for vestibular schwannoma. Moreover, the proposed technique reduces surgery time due to simpler craniotomy and wound closure.

Diagnosis and surgical outcomes in the management of petrous bone cholesteatoma

To evaluate the effectiveness of surgical treatment of patients with petrous bone cholesteatoma (PBC) depending on the localization of the pathological process. The analysis of surgical treatment using various surgical approaches and its results in 32 patients with PBC, depending on the type, localization in petrous bone and intraoperative findings, is presented. Patients with supralabirint PBC underwent extended atticoantromastoidotomy with tympanoplasty and mastoidoplasty with automaterials (n=19), labyrinthectomy (n=4), subtotal petrozectomy with labyrinthectomy and suturing of the external auditory meatus (EAM) (n=2). In infralabirint and infralabirint-apical PBC, a transotic approach was used with Rambo suturing of EAM (n=9). The pre-sigmoid approach was performed in 1 patient. With an extradural subtemporal approach, PBC of apical localization was removed in 1 case. After surgical treatment, hearing remained at the same level in 15 (47%) patients, 14 of them had deafness. In the early postoperative period, a temporary increase in bone conduction hearing thresholds by 10-20 dB was detected in 14 (44%) patients with their gradual recovery over 3 months. Deafness in the postoperative period developed in 3 (9%) patients after removal of supralabirint cholesteatoma. In the early postoperative period, 3 (9%) patients developed systemic dizziness, which was stopped after 3 months. In 25 (78%) patients, the function of the facial nerve in the early postoperative period remained at the same level, of which 14 (44%) were normal, and 11 (34%) had the same degree according to the House-Brackmann (HB) classification. Improvement of function by one degree of HB classification was observed in 4 (12.5%) patients on average 5 months after surgery. An adequate personalized choice of surgical treatment methods allowed mainly to preserve the function of hearing and facial nerve. In cases of deterioration of facial nerve function in the postoperative period, gradual improvement was observed for 3-10.5 months with further positive dynamics.

A Review of Delayed Facial Nerve Paresis as Complication Following Total Endoscopic Ear Surgery.

The aim of this study is to evaluate the incidence of delayed facial nerve paresis after total endoscopic ear surgery. This review also aims to describe the possible contributing factors and its management. This is a retrospective review of all patients who had undergone total endoscopic ear surgery for all otologic cases that required endoscopic intervention in a single otologic center from 2014 up to 2020. The delayed facial nerve paresis is defined as deterioration of facial nerve function 72 hours after total endoscopic ear surgery. A total of 56 patients were included in the study. Delayed facial nerve paresis following total endoscopic ear surgery was observed in 2 patients (3.4%). Facial weakness sets in on day 6 post operation and another one developed at day 16 after the surgery. Both patients were investigated and only one of them showed a higher titer of Varicella zoster virus antibody while another patient showed no raise of titer. Thus, explanation of postoperative edema or mechanical compression is discussed. The incidence of delayed facial nerve paresis following total endoscopic ear surgery is rare. It can occur probably several days after surgery up to 3 weeks. Our 2 cases revealed that virus reactivation may not be the only factor for delayed facial nerve palsy after surgery. The overall prognosis for incomplete delayed facial nerve paresis is very good as both patients recovered well few days after treatment with steroids.

Transient Subacute Facial Nerve Dysfunction After Dual Modality Treatment of Large Vestibular Schwannomas.

1: Describe subacute facial nerve paralysis after salvage stereotactic radiosurgery (SRS). 2: To analyze predictors of facial nerve weakness after dual modality treatment. Adult patients with Vestibular Schwannoma who underwent sub-total resection (STR) followed by salvage radiation. Microsurgical resection of VS, stereotactic radiosurgery, intensity-modulated radiotherapy, proton radiotherapy. Serial facial nerve function (House-Brackmann scale). Thirteen patients who underwent dual modality treatment for large VS were included (mean age = 43.6 years, 77% females). The mean pre-operative tumor volume was 11.7 cm3 (SD = 6.5) and the immediate mean post-operative remnant volume was 1.5 cm3 (SD = 1.4) with a mean extent of resection of 86.7% (SD = 9.5). The mean salvage-free interval was 20.8 months (SD = 13.3). All patients had excellent one-year FN outcome (HB grade 1, 2) after resection. Three patients developed subacute facial nerve weakness after salvage SRS (4.2-9.4 months after SRS). This paralysis responded to high dose systemic steroids and no surgical interventions for facial rehabilitation were required. At last follow up (mean 61.6 months, SD = 28.5), facial nerve function was favorable (HB grade 1-2 in 12 patients and HB grade 3 in 1 patient). There were no significant associations between various predictors and subacute deterioration of facial nerve function after SRS. Sub-acute transient facial nerve dysfunction can develop infrequently over a variable time frame after post-operative salvage SRS and usually responds to steroids. Patients should be adequately counseled about potential of transient deterioration of facial nerve function after salvage SRS.

PB6. A new motor threshold criterion for intraoperative corticobulbar MEP can predict postoperative facial nerve function

Objective Intraoperatively, facial nerve (FN) function is assessed with corticobulbar Motor Evoked Potentials (FN-coMEP). MEP-amplitude decrement and increase in motor threshold (MT) serve as warning criteria. A novel threshold criterion for extremity muscle MEP compares final-to-baseline motor threshold levels (BFB-MT) between the operated versus non-operated side. We applied BFB-MT for FN-coMEP with regard to postoperative FN-function. Methods 79 patients (45f; 48 ± 16 yrs., 68% vestibular schwannoma) undergoing cerebellopontine angle tumor surgery were analysed. FN-function was assessed with the House-Brackmann score (HB) pre- and postoperatively at day 1 (d1), 7 (d7), 3 months (3 m) and grouped in mild (HB score increase ⩽ 1) or marked deterioration (HB score increase ⩾ 2). FN-coMEP were elicited with anodal transcranial electric stimulation at C4;C3 referenced to Cz, and recorded from oris and mentalis muscles. A BFB-MT difference ⩾ 20% (operated vs. non-operated side) was considered significant. MT-increase of ⩾ 20 mA and amplitude decrement ⩾ 50% on the operated side served as reference criteria. FN function was correlated to all 3 criteria. Results At d1, 22% of patients (17/79) showed mild HB deterioration, 27% (21/79) marked. At d7, 25% (20/79) showed mild and 16% (13/79) marked deterioration. At 3 m follow-up (available in 68 patients), 94% showed recovery (64/68). Only 4/68 patients showed residual marked FN function deterioration. FN-coMEP were obtained in 95% cases (75/79). Changes according to BFB-MT (35 ± 17 mA) occurred in 17 patients, 16 of these patients suffered a marked deterioration of FN function at d1. BFB-MT correlated significantly with FN function at d1 and d7. The correlation was stronger using the BFB-MT (Spearman correlation: d1: p = 0.726; d7: p = 0.559; 3 m: p = 0.265) compared to absolute threshold increase ⩾ 20 mA (Spearman correlation: d1: p = 0.675; d7: p = 0.528; 3 m: p = 0.275) and amplitude reduction ⩾ 50% (Spearman correlation: d1: p = 0.305; d7: p = 0.378; 3 m: p = 0.118). Conclusion An increase of BFB-MT ⩾ 20% between the operated vs. non-operated side serves as a better predicator for postoperative FN function than absolute mA increase and amplitude reduction. Further studies have to validate this criterion intraoperatively for its real time applicability.

The difficulty of predicting clinical outcome after intended submaximal resection of large vestibular Schwannomas

IntroductionIntended subtotal resection of large vestibular schwannomas (T4a and b according to the Hannover classification system) has been shown to be safe and, in combination with stereotactic radiosurgery, might enable sufficient tumor control. However, risk factors for postoperative neurological deterioration in these surgically challenging lesions are largely unknown. MethodsPre- and postoperative symptoms, clinical and radiological data of patients who underwent intended subtotal resection for vestibular schwannoma in our department between 2010 and 2014 were reviewed. Risk factors for postoperative neurological deterioration were analyzed in uni- and multivariate analyses. Results63 patients harboring T4a (N = 33, 52%) or T4b (N = 30, 48%) tumors were included. At time of discharge, facial nerve and hearing function had deteriorated from a serviceable to a non-serviceable level (H&B grades I + II vs. >II) in 24% (N = 15/63) and 21% (N = 6/29), respectively. Deterioration of vertigo was more common after near (N = 3/9, 33% vs. 2/38, 5%) than after subtotal resection (<.25 ccm vs. ≥ .25 ccm tumor remnant on the initial postoperative MRI; p = .042). No further correlation with patient age, sex, neurofibromatosis, resection extent and tumor volume, or -cyst volume was found. Patients were reevaluated after a median of 3 months after surgery. At that time, facial nerve function and hearing had both decreased from a preoperative serviceable to a non-serviceable level in 5%. In univariate analyses, risk of deterioration of facial nerve function increased with preoperative tumor volume (p = .037). ConclusionIntended submaximal resection provides satisfactory neurological outcome for patients with large VS. Risk factors for postoperative neurological deterioration remain unclear.

P 108 Modified motor threshold criterion for intraoperative corticobulbar MEPs for prediction of postoperative facial nerve outcome

Background Intraoperatively, facial nerve (FN) function can be assessed with corticobulbar Motor Evoked Potentials (FN-coMEP). MEP-amplitude decrement and increase in motor threshold (MT) serve as warning criteria. A novel threshold criterion for extremity MEP additionally compared MT-increments to the non-operated side (bilateral final-to-baseline motor threshold level, BFB-MT). We applied BFB-MT for FN-coMEP with regard to postoperative FN-function. Methods 47 consecutive patients (26f; 46 ± 18 yrs) undergoing posterior fossa tumor surgery (40 cerebellar pontine angle; 6 petroclival, 1 foramen magnum) were analyzed. FN-coMEP were elicited with anodal transcranial electric stimulation at C4; C3 referenced to Cz, and recorded from bilateral orbicularis oris and mentalis muscles. Preoperative and one day (1d), one week (1w) and 3 month (3m) postoperative House-Brackmann FN-function scores were compared and deterioration was classified as mild (increase ⩽1) or marked (increase ⩾2). BFB-MT difference of >20% (operated vs. non-operated side) was regarded as significant. Increase of MT on the operated side of ⩾20 mA served as reference criterion (RefC). The predictive value was analyzed and compared by χ 2 test, nonparametric Spearman correlation, and Logistic regression analysis. Results At 1d, 15% of the patients (7/47) showed mild HB deterioration, 36% (17/47) marked. At 1w, 12 patients showed mild deterioration (25%), 10 marked (19%). 3 m follow-up in 40 patients (85%) showed recovery in 31 patients (78%). 5 patients (13%) showed mild and 4 (10%) marked deterioration (all in giant or recurrent tumor). The overall technical success rates of FN-coMEP on the operated and non-operated side of the tumor were 93.6% and 87.2%. For the 21 patients with stable FN outcomes, the mean final-to-baseline threshold increment on operated side was 6.7 ± 4.6 mA compared to 2.8 ± 3.4 mA (p = 0.005) on the contralateral side. In 23 patients enduring postoperative deterioration of FN function, mean BFB-MT threshold increment on operated side was 24.1 ± 18.6 mA, compared to 9.2 ± 9.7 mA (p = 0.001) on the non-operated side. A significant statistical difference also existed in the threshold increment between these two subgroups (p). Conclusion BFB-MT serves as better indicator for postoperative FN function than the RefC. Further, it was identified as a variable for postoperative FN-function at 1w and seems to be a useful method for predicting the postoperative facial function. Such, FN-coMEP are feasible as a routine method for intraoperative FN monitoring and might help to tailor warning criteria.

Staging in giant vestibular schwannoma surgery: A two consecutive day technique for complete resection in basic neurosurgical setups

ABSTRACT Introduction: Vestibular schwannomas constitute 8% of all intracranial tumors. A majority of vestibular schwannomas are sporadic and unilateral. Giant vestibular schwannomas are seen in our country due to the late diagnosis and long duration of symptoms before diagnosis. These giant schwannomas are challenging to manage as most of the patients are having brainstem compression. Materials and Methods: Twelve cases of a giant vestibular schwannoma were operated in our department between May 2011 and December 2012. Vestibular schwannomas with a maximal diameter of more than 4 cm were defined as a giant vestibular schwannoma. All the patients had a unilateral vestibular schwannoma. Performance status of all the patients were graded as per the Karnofsky performance score. Pre-operative assessment of 5th, 7th, 8th and lower cranial nerve status was done in all cases. Ventriculoperitoneal shunting was done pre-operatively in all cases. All patients were operated through retromastoid suboccipital craniectomy and retrosigmoid approach. These patients were operated in two stages in two consecutive days with overnight elective ventilation in ICU. Ultrasonic aspirator and nerve monitoring techniques were not used. Results: Giant acoustic schwannomas can be safely resected completely by a staged resection on two consecutive days without any increased morbidity or mortality. This technique may be employed to achieve complete resection of such lesions without deterioration of facial nerve function in institutions which do not have advanced facilities like nerve monitoring or ultrasonic aspirator.

Microsurgery for Large Vestibular Schwannomas: A Series of 45 Patients

Objective: Vestibular schwannomas (VS) presented for surgery in an era of radiosurgery are mainly large tumors (>2.5 cm). We present a retrospective study to assess our surgical results. Study Design: We reviewed the data of 45 patients with large VS operated in our center from 2008 to 2013. We evaluated tumor volume, cranial nerve status, surgical approach, extent of resection, complications, tumor recurrence, and postoperative complaints. We compared the results with the larger series described in the literature. Results: Mean age was 46 years. Mean follow-up was 21 months. Tumor size was on average 31.2 mm. Retrosigmoidal (40%), translabyrinthine (55%), and presigmoidal retrolabyrinthine (5%) approach was used. Gross-total resection was obtained in 38 patients (85%), near-total in 6 (13%), and a subtotal in 1 patient (2%), respectively. Tumor control rate at last follow-up was 100% without additional treatment. Hearing preservation surgery was only successful in four patients. Early deterioration of facial nerve function was seen in 42% but improved to normal function in 78%. Late follow-up documented frequent complains of headache (29%) and vestibular dysfunction (52%). Conclusion: We present a series of surgically treated large VS. Our results are comparable to larger studies. Concerning facial nerve preservation the question rises whether subtotal removal and adjuvant treatment is an option with equal tumor control in the long run.

Staging in giant vestibular schwannoma surgery: A two consecutive day technique for complete resection in basic neurosurgical setups.

Introduction:Vestibular schwannomas constitute 8% of all intracranial tumors. A majority of vestibular schwannomas are sporadic and unilateral. Giant vestibular schwannomas are seen in our country due to the late diagnosis and long duration of symptoms before diagnosis. These giant schwannomas are challenging to manage as most of the patients are having brainstem compression.Materials and Methods:Twelve cases of a giant vestibular schwannoma were operated in our department between May 2011 and December 2012. Vestibular schwannomas with a maximal diameter of more than 4 cm were defined as a giant vestibular schwannoma. All the patients had a unilateral vestibular schwannoma. Performance status of all the patients were graded as per the Karnofsky performance score. Pre-operative assessment of 5th, 7th, 8th and lower cranial nerve status was done in all cases. Ventriculoperitoneal shunting was done pre-operatively in all cases. All patients were operated through retromastoid suboccipital craniectomy and retrosigmoid approach. These patients were operated in two stages in two consecutive days with overnight elective ventilation in ICU. Ultrasonic aspirator and nerve monitoring techniques were not used.Results:Giant acoustic schwannomas can be safely resected completely by a staged resection on two consecutive days without any increased morbidity or mortality. This technique may be employed to achieve complete resection of such lesions without deterioration of facial nerve function in institutions which do not have advanced facilities like nerve monitoring or ultrasonic aspirator.

Neuroprotective Efficacy of Prophylactic Enteral and Parenteral Nimodipine Treatment in Vestibular Schwannoma Surgery: A Comparative Study

BACKGROUND AND STUDY AIMS/OBJECT: Oral nimodipine improves neurologic outcome after aneurysmal subarachnoid hemorrhage. In addition, the neuroprotective efficacy of nimodipine has been revealed following skull base, laryngeal, and maxillofacial surgery. Pharmacokinetic investigations showed nimodipine to reach higher serum levels following parenteral versus enteral administration. Furthermore, a correlation between nimodipine levels in serum, cerebrospinal fluid, and nerve tissue could be quantified. These observations raise the question whether the proven neuroprotective effect of nimodipine is related to its serum level. A consecutive series of 37 patients with vestibular schwannoma treated with nimodipine from the day before surgery until the seventh postoperative day was analyzed retrospectively. Both groups received standard dosages for enteral (n = 17) and parenteral (n = 20) nimodipine medication. Nimodipine levels were measured in pre- and postoperative serum and cerebrospinal fluid samples. Cochlear and facial nerve functions were documented before surgery, in the early postoperative course, and 1 year after surgery. Facial nerve outcome was significantly better in the group with parenteral nimodipine medication (p = 0.038). Logistical regression analysis revealed a seven times smaller risk for a deterioration of facial nerve function in the group with parenteral treatment. There was no difference in hearing preservation between both groups despite tumor size tending to be larger in the parenteral group. Intraoperative (p = 0.004), postoperative (p = 0.001), and serum and cerebrospinal fluid (p = 0.024) nimodipine levels were significantly higher following parenteral administration as compared with enteral administration. Both groups were comparable regarding tumor size and extent of resection. These results support a dependency of nimodipine's neuroprotective efficacy on its serum levels. Parenteral nimodipine treatment produces higher serum levels and has a higher neuroprotective potency in vestibular schwannoma surgery compared with enteral treatment.

Ocena ryzyka uszkodzenia nerwu twarzowego i pogorszenia słyszenia u chorych operowanych z powodu guza nerwu przedsionkowo-słuchowego

AimTo compare hearing preservation possibilities and facial nerve outcomes between middle fossa (MF) and translabyrinthine (TL) approach in patients undergoing vestibular schwannoma surgery. Material and methodsRetrospective analysis of medical records of 104 patients treated otosurgically due to vestibular schwannoma. All patients underwent surgery using one of the two approaches: 41 MF and 63 TL. The risks of deterioration of the facial nerve function as well as hearing were evaluated. ResultsStatistical significance was found between the two surgical groups in hearing results, and no significance in facial nerve outcomes. In addition analysis revealed that facial nerve outcomes correlated with the size of the tumor. ConclusionsMiddle fossa approach offers possibility to resect vestibular schwannomas with hearing preservation. In case of translabyrinthine approach the hearing becomes permanently damaged due to the surgical technique. The risk of deterioration of facial nerve function correlates with the size of the tumor (larger the tumor bigger the risk), however, there is no correlation when it comes to surgical approach (Mf or TL).

A-trains for intraoperative monitoring in patients with recurrent vestibular schwannoma

Second surgery of recurrent vestibular schwannoma (VS) after previous surgery, stereotactic radiosurgery (SR) or fractionated radiotherapy (FR) carries an increased risk for deterioration of facial nerve function, e.g., due to adhesions, underlining the need for intraoperative monitoring. Facial “Atrain” EMG activity (“traintime”) correlates with the degree of postoperative facial palsy. Studies investigating A-trains in VS patients with previous surgery, SR or FR are missing. We therefore investigated the value of A-train monitoring in patients undergoing second surgery for VS. Intraoperative EMG data from patients who underwent second surgery for VS after previous surgery, SR and/or FR at our institution between 2006 and 2012 were retrospectively analyzed. Ten patients were selected (5 male): Seven had previous SR/RT and MS, three previous surgery only. Traintime values and distribution was compared to published thresholds and to 77 patients who underwent first surgery for VS during the same time period. A-trains were recorded early after opening of the dura, before facial nerve preparation. Mean traintime was 46.9 s (18.51 s – 80.82 s) in patients with previous SR/RT. In patients with previous MS only, traintime was 0.06 s, 0.99 s and 22.46 s. Compared to the literature, traintime was higher than expected in six patients (four with previous SR/RT, two without), respectively seven compared to the 77 patients with first surgery (5 SR/RT). Seven patients with previous SR/RT and none with previous surgery showed diffuse A-train distributions without significant percentages in single channels, compared to 60 of 77 patients with first surgery (p <0.02). Especially SR/RT, but also previous surgery seems to induce changes in the facial nerve leading to hyperexcitability and exceedingly high traintime values. Based on these findings, A-train monitoring in this specific patient group should be interpreted with caution.

Spontaneous Electromyographic Activity During Microvascular Decompression in Trigeminal Neuralgia

Intraoperative monitoring of spontaneous facial nerve electromyographic activity during surgery for microvascular decompression in trigeminal neuralgia was evaluated. Fifteen patients with trigeminal neuralgia underwent surgery for microvascular decompression. During the entire operation, free-running facial nerve electromyographic signals were recorded. The data were analyzed with respect to waveform patterns known from vestibular schwannoma-surgery. Special regard was given to the occurrence of A-trains that are associated with postoperative paresis in patients operated on vestibular schwannoma. The spectrum of the observed activities matched patterns known from surgery of vestibular schwannoma; even A-trains, a pattern known to be an indicator of postoperative deterioration of facial nerve function (Romstöck et al., J Neurosurg 2000;93:586-593), were seen in 3 of the 15 patients with trigeminal neuralgia. The quantity of A-trains observed was much less than it is known from patients operated on tumors of the cerebellopontine angle. None of the trigeminal neuralgia-patients experienced postoperative deterioration of facial nerve function. The present study shows that A-trains do not only occur during tumor surgery, but also during procedures with indirect manipulation of the facial nerve. They do not necessarily lead to postoperative paresis as long as certain thresholds concerning amount and length of these A-trains are not exceeded.

Train time as a quantitative electromyographic parameter for facial nerve function in patients undergoing surgery for vestibular schwannoma

The authors describe a quantitative electromyographic (EMG) parameter for intraoperative monitoring of facial nerve function during vestibular schwannoma removal. This parameter is based on the automated detection of A trains, an EMG pattern that is known to be associated with postoperative facial nerve paresis. For this study, 40 patients were examined. During the entire operative procedure, free-running EMG signals were recorded in muscles targeted by the facial nerve. A software program specifically designed for this purpose was used to analyze these continuous recordings offline. By automatically adding up time intervals during which A trains occurred, a quantitative parameter was calculated, which was named "train time." A strong correlation between the length of train time (measured in seconds) and deterioration of postoperative facial nerve function was demonstrated. Certain consecutive safety thresholds at 0.5 and 10 seconds were defined. Their transgression reliably indicated postoperative facial nerve paresis. At less than a 10-second train time, discrete worsening, and at more than 10 seconds, profound deterioration of facial nerve function can be anticipated. Train time as a quantitative parameter was shown to be a reliable indicator of facial nerve paresis after surgery for vestibular schwannoma.

Preservation of Facial Nerve Function after Postoperative Vasoactive Treatment in Vestibular Schwannoma Surgery

Facial nerve paresis and hearing loss are common complications after vestibular schwannoma surgery. Experimental and clinical studies point to a beneficial effect of nimodipine and hydroxyethyl starch for preservation of cochlear nerve function. A retrospective analysis was undertaken to evaluate the effect of vasoactive treatment on facial nerve outcome. Forty-five patients with vestibular schwannoma removal, intraoperative electromyographic monitoring, and postoperative deterioration of facial nerve function were evaluated. Twenty-five patients underwent vasoactive treatment consisting of nimodipine and hydroxyethyl starch for improvement of hearing outcome. Twenty patients did not receive such treatment. Facial nerve function was evaluated before and after surgery, as well as 1 year after the surgical procedure. Patients were comparable regarding age, tumor size, and preoperative facial nerve function. Long-term results of facial nerve function were significantly improved in those patients who experienced severe postoperative deterioration of facial nerve function and received vasoactive treatment as compared with patients who did not receive nimodipine and hydroxyethyl starch after surgery. Treated patients showed a significantly higher rate of complete recovery compared with patients without treatment. The study points to a potential effect of vasoactive treatment for facial nerve function after vestibular schwannoma surgery. In particular, patients with postoperative disfiguring facial nerve palsy clearly benefit from intravenous hydroxyethyl starch and nimodipine with respect to a long-term socially acceptable facial nerve function.

Viral titers and delayed facial palsy after acoustic neuroma surgery.

Delayed facial palsy (DFP) after acoustic neuroma surgery has been reported to occur in up to one third of cases. Reactivation of latent virus has been proposed as an etiology for DFP. However, only retrospective case reports and case series have offered data to support this theory. The objective of this study was to correlate DFP with change in viral titers. Twenty consecutive patients who underwent acoustic neuroma surgery were prospectively evaluated for viral titers immediately preoperatively and at 3 weeks postoperatively. Viral titers measured included herpes simplex virus 1 (HSV-1), herpes simplex virus 2 (HSV-2), and varicella zoster virus (VZV) and included both IgG and IgM titers. The status of facial nerve function was documented preoperatively and throughout the postoperative period. Patients were categorized according to the presence or absence of DFP. Seven patients developed DFP after acoustic neuroma surgery, while the remaining 13 patients did not. There was no difference in preoperative and 3-week postoperative IgG titers for any of the 3 viruses tested. However, IgM titers were much higher postoperatively in DFP patients for all 3 viruses tested. The average HSV-1 IgM titer rose 92% in DFP patients compared with only 4.5% in the patients who did not develop DFP. Average HSV-2 IgM titers rose 70% compared with a decline of 8.5% in non-DFP patients. Most strikingly, VZV IgM titers rose an average 495% postoperatively among DFP patients compared with a decline of 14% in the non-DFP patients. Elevation of the IgM titers of the viruses measured in this study implies that recrudescence of the virus has occurred. The absence of this rise among patients who did not develop DFP implies that viral recrudescence plays a role in the etiology of DFP. These findings support treatment or prophylaxis of DFP with antiviral therapy.

Delayed facial palsy after resection of vestibular schwannoma

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. 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 (< or = two House-Brackmann grades) had occurred at a mean of 10.2 days postsurgery, whereas in nine patients (60%) moderate deterioration (> or = 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. 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.

Delayed facial palsy after vestibular schwannoma surgery

Objective: there is a lack of uniformity in the literature of the definition of delayed facial palsy (DFP) after vestibular schwannoma surgery. The aim of this study was to attempt to provide a clear definition of this clinical entity. Methods: a prospective study was undertaken of all patients, with an intact facial nerve postoperatively, undergoing vestibular schwannoma surgery during a 16-month period. Delayed facial palsy was defined as any worsening of facial function after the initial assessment of postoperative function. Results: a total of 67 patients, operated on between February 1994 and June 1995 satisfied the requirements of the study. Eight of the 67 patients developed a worsening of facial function after the first postoperative day. There were three males and five females with an age range of 29–73 years (mean, 53 years). Conclusion: DFP should be defined as any deterioration of facial function after vestibular schwannoma surgery.