Cerebellopontine Angle Tumor Surgery Research Articles

Descending hypoglossal branch-facial nerve anastomosis for severe facial paralysis after cerebellopontine angle tumor surgery

Objective To investigate the clinical effect of descending hypoglossal branch-facial nerve anastomosis for severe facial paralysis after cerebellopontine angle (CPA) tumor surgery. Methods From October 2010 to February 2014, 17 patients with severe facial paralysis whose House-Brackmann (H-B) grades were 5-6 or without clear facial nerve anatomical reservation after CPA tumor surgery were treated with the descending hypoglossal branch-facial nerve anastomosis at the Department of Neurosurgery, Beijing Xuanwu Hospital, Capital Medical University. Their clinical efficacy was observed retrospectively. Results After neuroanastomosis, no disability and death, no hoarseness, dysphagia and other neurological disorders were observed. In 17 patients, 15 (88.2%) were followed up for 6 to 53 months (mean 25). Facial nerve function H-B grade 2 was in 4 patients, grade 3 in 5 (33.3%), grade 4 in 5 (33.3%), and grade 5 in 1. One patient suffered ipsilateral tongue paralysis completely after procedure. The improvement of facial paralysis was most significant for orbicularis muscles, followed by the orbicularis oculi muscles, and the worst was the improvement of frontal muscles. All the patients benefited from the anastomosis. Although there was no significant improvement for patients with facial paralysis H-B grade 5, the patients felt that the dry eyes, the degree of redness and swelling reduced compare with before procedure. Conclusion Descending hypoglossal branch-facial nerve anastomosis can not only improve the facial nerve function in patients with severe facial paralysis in tumors of CPA regions, but also can avoid the influence on the hypoglossal nerve function. Key words: Cerebellopontine angle; Central nervous system neoplasms; Facial paralysis; Anastomosis, surgical; Facial nerve; Descending hypoglossal branch

Surgical Outcome of Cerebellopontine Angle Tumors: A Study of 24 Cases at the Department of Neurosurgery, Bangabandhu Sheikh Mujib Medical University, Dhaka

Background: The cerebellopontine angle is a space defined by the pyramid anterolaterally, the tentorium superiorly, the pons medially and cerebellum dorsomedially. It is difficult to approach for its complication and vital structures.
 Objective: To see the outcome of surgery of cerebellopontine angle tumors at the Bangabandhu Sheikh Mujib Medical University.
 Results: Among the 24 patients 16(66.66%) were males. It was evident that 14(58.33%) belonged to the age group 41-60 years. It was documented that the majority 19(79.16%) of patients had vestibular schwannoma. Among the clinical signs and symptoms the highest group had hearing loss 20(80%). Among 24 patients the tumor was removed completely in 15(62.50%). Among the post operative complications 4(16.66%) developed facial palsy. 2(8.33%) of patients had lower cranial nerve palsy. After operation 1(4.16%) patient died due to aspiration pneumonia.
 Conclusion: Cerebellopontine angle tumor surgery is a very difficulty operation. But at a tertiary hospital, with help of microscope, we can remove the tumor completely.
 Bangladesh Journal of Neuroscience 2014; Vol. 30 (2): 90-95

Diagnosis and Management of Dural Sinus Thrombosis following Resection of Cerebellopontine Angle Tumors.

Objective Lateral sinus thrombosis is a potentially devastating but seldom studied complication of cerebellopontine angle (CPA) tumor surgery. Systemic anticoagulation in the early postoperative period has often been avoided due to the potential risks of intracranial hemorrhage. Design Retrospective review. Setting Tertiary referral center. Main Outcome Measures The goal of this study was to identify the frequency, treatment, and outcomes in patients who develop postoperative venous sinus thrombosis following CPA tumor surgery and receive early systemic anticoagulation. Results Of 43 patients with CPA tumors, we report five patients (11.6%) with transverse and/or sigmoid sinus thrombosis following resection of the tumor, four of which were detected on routine early postoperative noncontrast computed tomography (CT) scan. The thrombosis was confirmed in all cases with CT venography or magnetic resonance venography. Affected patients had significantly larger tumors than controls and tended to undergo longer operations. These patients were treated with immediate anticoagulation (intravenous heparin, followed by Coumadin for 6 months) without complication. Conclusion Venous sinus thrombosis is an underrecognized complication of CPA surgery, but it can be diagnosed in the early postoperative period by noncontrast CT imaging. Early postoperative initiation of systemic anticoagulation appears safe and effective to prevent the progression of thrombosis and its consequences.

Facial nerve anastomosis for facial paralysis resulting from surgery of cerebellopontine angle tumors

Objective To evaluate the efficiency and functional improvement of the facial nerve anastomosis for facial paralysis after cerebellontine angle (CPA) tumor surgery.Methods The clinical data of seven patients with facial paralysis after CPA tumors surgery underwent nerve anastomosis were analyzed retrospectively.House-Brackmann (H-B) grading was used to evaluate the pre-,post-operative and follow-up status.The end-end anastomosis of facial nerve was performed in one case,and facial-hypoglossal nerve anastomosis in six.Results All patients were followed-up.The mean time of follow-up was 23 months (ranged from 1 to 48 months).Among seven cases,the facial nerve function was improved in five cases,unchanged in one,and could not be evaluated in one because of short-time follow-up.The postoperative HB grades were Ⅱ in one case,Ⅲ in two and Ⅳ in two.Conclusions Facial nerve anatomosis was a useful treatment for facial paralysis after CPA tumors resection and could improve the facial function. Key words: Facial nerve injuries; Facial Palsy; Cerebellopontine angle; Nerve anastomosis

89. Facial nerve monitoring during cerebellopontine angle surgery: Our experience

Intraoperative facial nerve neuromonitoring (FN-IOM) has been established as one of the methods by which neurosurgery can improve surgical results while reducing morbidity. Despite routine use of FN-IOM, FN injury is still a complication of major concern due to severe impact on patient’s quality of life. Currently, standard monitoring techniques comprise direct electrical stimulation (DES), free-running electromyography (EMG) and facial motor evoked potential (FMEP). Recently, intraoperative recording of Blink Reflex (BR) can also be used. We report our experience of FN-IOM in 56 patients who underwent surgery for cerebellopontine angle tumors, trigeminal neuralgias or hemifacial spasms. FN was monitored with DES, EMG and, in 19 patients, also with BR. Facial nerve outcomes were evaluated one week and six months after surgery using the House–Brackmann scale (HB). Nine patients (16,1%) had HB grade III–VI function at 6 months after surgery. Individually, DES and EMG can predict FN function at 6 months, but used together, in a multimodal monitoring approach, the sensibility is higher. BR can predict FN function only one week after surgery. With our experience we want to emphasize the role of multimodal FN monitoring and its impact on facial nerve function preservation.

The analgesia nociception index monitor (ANI) can detect indvertent vagal stimulation during surgery of cerebello-pontine angle tumors

The analgesia nociception index monitor (ANI) can detect indvertent vagal stimulation during surgery of cerebello-pontine angle tumors

Preoperative Detection of the Facial Nerve Location Using Balanced Fast Field Echo and Diffusion Tensor Imaging in Patients with Large Cerebellopontine Angle Tumors

Objective: Facial nerve preservation is an important issue in surgery of large cerebellopontine angle (CPA) tumors. We tried to predict the location of facial nerve in large CPA tumors using 3-tesla MRI, and verified by intraoperative findings.

Early complications and symptoms of cerebellopontine angle tumor surgery: a prospective analysis

Our objective is to prospectively report very early complications and outcomes of cerebellopontine angle (CPA) surgery. Between January and August 2007, 72 patients were operated on by different transpetrosal approaches in a tertiary referral center. During preoperative assessment, facial nerve function (House-Brackmann grading system), the presence of vertigo or tinnitus and caloric test results were recorded and correlated with complications and symptoms occurring daily from day (D) 1 to D 8. The overall number of complications did not differ from those of former retrospective studies; nevertheless, the prospective feature of this study prompts several comments. Even slight (grade II) preoperative facial impairments increased the risk of severe postoperative facial dysfunction. Keratitis was frequent (42%) even in patients with normal facial function. Thrombo-embolic complications only occurred after long air-travel (≥5 h). Preoperative caloric test status was predictive of postoperative vestibular disturbance occurrence. With respect to the activity recovery; younger patients (<40 years old) displayed faster central compensations than the older (>60 years old) patients. This study highlights several features that may be used for preoperative patient counseling and complication management. In particular, the practitioner has to pay attention to even minor preoperative clinical signs of facial dysfunction to properly inform the patient of facial outcome. Routine ophthalmologic evaluation should be practiced, even when facial function is normal or subnormal. 1b.

The role of the trigeminocardiac reflex in postoperative hearing function in non-vestibular schwannoma cerebellopontine angle tumors

The trigeminocardiac reflex (TCR) is a common event during skull base surgery that can lead to intraoperative arterial hypotension and bradycardia. Arterial hypotension associated with TCR can be a negative prognostic factor for postoperative auditory function and ipsilateral tinnitus in patients undergoing surgery for vestibular schwannoma (VS). In this study, the contribution of TCR to postoperative auditory function in non-VS cerebellopontine angle (CPA) tumor surgery was investigated. From a consecutive series of 102 patients with CPA tumors, we studied the occurrence of TCR and its influence on postoperative auditory function in patients with non-VS tumors. Pre- and postoperative auditory function, pre- and intraoperative mean arterial blood pressure, as well as preoperative medication, tumor size, and occurrence of TCR were evaluated. Of the 35 patients evaluated, four developed intraoperative TCR, of whom one was preoperatively deaf. Preoperative functional hearing was detected in 30/35 patients (85.7%): preoperative deafness was documented in one patient in the TCR group and in four patients in the non-TCR group. Of the 30 patients with preoperative functional hearing, 1/3 (33.3%) patients in the TCR group and 23/27 (85.2%) patients in the non-TCR group had functional hearing postoperatively. When patients with large tumors and functional, hearing were considered, only 33.3% of patients in the TCR group and 77.8% of patients in the non-TCR group remained within the same hearing classes following surgical treatment ( p = 0.1573). TCR may be a negative prognostic factor for postoperative auditory function in patients with large, non-VS CPA tumors.

Intraoperative Brainstem Auditory Evoked Potential Observations After Trigeminocardiac Reflex During Cerebellopontine Angle Surgery

The occurrence of trigeminocardiac reflex (TCR) is known to be a negative prognostic factor for hearing preservation in cerebellopontine angle tumor surgery. Our study was conducted to investigate brainstem auditory evoked potential (BAEP) changes after this reflex in cerebellopontine angle tumor surgery and to evaluate their impact on postoperative hearing function. Five of 102 consecutive patients had an intraoperative TCR (4.9%) and were retrospectively evaluated for the intraoperative BAEP changes after TCR and postoperative auditory function (7 to 10 d after surgery). One of the 5 patients was preoperatively deaf and therefore excluded from this analysis. Four patients with preoperative functional hearing developed one or more episodes of TCR. Intraoperative BAEP was maintained in 1 patient, whereas in 3 cases an acute intraoperative BAEP deterioration occurred within 2:04 to 3:27 minutes (mean 2:44 min) after TCR with increased wave latency, decreased wave amplitude, and even wave loss. Two patients had deteriorated BAEP waves until the surgical completion and were postoperatively deaf. Although no direct cause-effect relationship has yet been shown, we suggest TCR as an additional event that may cause BAEP changes. The observed BAEP alterations occurred minutes rather than seconds after the TCR incident leading to both temporary and permanent wave deterioration. This association of BAEP deterioration and TCR occurrence, however, remains yet to be proven justifying further study in the field.

CSF fistulae following surgery for cerebellopontine angle tumours and their relationship with the body mass index

IntroductionThe most frequent complication after vestibular schwannoma surgery is cerebrospinal fluid (CSF) fistula. Material and methodsRetrospective study of 170 patients who had vestibular schwannoma (163) or other tumours in the cerebellopontine angle (CPA) (7). Resection was carried out using different approaches: retrosigmoid (66%), translabyrinthine (24%), middle cranial fossa (5%), and others (5%). We studied the day of onset, location and treatment of the CSF leaks, and the influence of demographic, radiological and clinical variables, including body mass index. ResultsTwenty-seven patients developed a CSF fistula (15.9%): fifteen were incisional (8.8%), 8 patients developed CSF rhinorrhea (4.7%), 1 CSF otorrhea (0.6%), and 3 a combination of the above (1.8%). We controlled 11 CSF fistulae with bed rest and compressive dressings (6.5%), 7 required lumbar drainage (4.1%), 2 lumbar drainage and wound closure with local anaesthesia (1.2%), and 7 patients required returning to the operating room under general anaesthesia (4.1%). There was not a significant relationship between the apparition of CSF and tumour size, type of approach, age, or body mass index (BMI). ConclusionsDespite the great development and new surgical techniques, CSF fistulae are still a frequent complication after VS surgery. There might be other aetiological factors such as intracranial pressure. There was no significant relationship between CSF fistula and BMI. Adequate management and early conservative measures led to reduced reintervention rates of less than 5% in all patients.

Analysis of Electrocochleography Morphology Changes Recorded Intraoperatively during Cerebellopontine Angle Tumor Surgery

Analysis of Electrocochleography Morphology Changes Recorded Intraoperatively during Cerebellopontine Angle Tumor Surgery

Intraoperative Changes of Brainstem Auditory Evoked Potentials during the Trigeminocardiac Reflex in Cerebellopontine Angle Surgery

Object: The trigeminocardiac reflex (TCR) is known to be a negative prognostic factor for hearing function in cerebellopontine angle (CPA) tumor surgery. The pathophysiological mechanism for this phenomenon has been unclear until now. Therefore, this study was conducted to analyze electrophysiological changes during this reflex in CPA tumor surgery.

Various Strategies of Intraoperative Monitoring of Hearing during CPAT Surgery

Purpose: Investigation of three strategies of intraoperative monitoring (IM) of auditory function during cerebellopontine angle tumor (CPAT) surgery: transtympanal electrocochleography (TT-ECochG), auditory brainstem responses (ABR), and distortion product otoacoustic emissions (DPOAEs).

Walter Edward Dandy (1886–1946)

Dandy was a leading light in the initiation and development of neurosurgery, not only in his native America but also throughout the world. This paper attempts briefly to outline his main achievements. After a turbulent relationship with Cushing he emerged as a brilliant, if vain, surgeon and investigator, based mainly at Johns Hopkins. He initiated air ventriculography and effected original studies on cerebrospinal fluid formation and circulation. The Dandy-Walker syndrome, surgery for aneurysms and cerebellopontine angle tumours were but a few areas where he made his mark and left a lasting legacy of neurosurgical endeavour.

A model of real time monitoring of the cochlear function during an induced local ischemia

The aim of this study was to investigate the utility of distortion product otoacoustic emissions (DPOAEs) in intraoperative monitoring (IM) of cochlear ischemic episodes in animals during internal auditory artery (IAA) compression. The IAA was exposed using the posterior fossa approach and then compressed for 3 and 5 min intervals to effect ischemia. DPOAE amplitudes and phases were measured at 4, 8, and 12 kHz geometric mean frequency (GMF). In each monitored ear, laser-Doppler cochlear blood flow (CBF) was measured. All IAA compressions resulted in rapid decrease of DPOAE amplitude and CBF, with simultaneous DPOAE phase increase. DPOAE phase changes were found to increase consistently within several seconds of IAA compression, while corresponding DPOAE amplitudes changed more slowly, with up to 30–40 s delays. Following IAA release, DPOAEs at 12 kHz GMF were characterized by longer delays in returning to baseline than those measured at lower frequencies. In some cases, CBF did not return to baseline. In this animal model, DPOAEs were found to be sensitive measures of cochlear function during transient cochlear ischemic episodes, suggesting the utility of DPOAE monitoring of auditory function during surgery of cerebello-pontine angle tumors.

Brainstem auditory evoked potential monitoring

The probability of hearing loss during cerebellopontine angle (CPA) surgery can be reduced by using brainstem auditory evoked potential (BAEP) intraoperative monitoring (IOM). A wave V latency prolongation of 1.0 milliseconds or amplitude decrement of greater than 50% is arbitrarily considered the point when damage to hearing occurs. To determine the accuracy of wave V changes in predicting hearing impairment. Patients undergoing BAEP IOM for surgery in the CPA region were evaluated. The greatest wave V latency and amplitude change was determined. Patients were divided into four groups depending on degree of change of wave V: Group 1 consisted of minimal change, whereas Group 4 was permanent loss of wave V. The frequency of hearing loss in each group was compared. Data from 156 patients were reviewed. When all patients were analyzed, the frequency of hearing loss was not significantly different between the groups. When patients with CPA tumor were excluded, a significantly higher number of patients in Group 4 had hearing loss. Analysis of the patients with CPA tumor showed no difference in the frequency of hearing loss in any of the groups; even a large number (50%) of Group 1 patients had hearing impairment. During brainstem auditory evoked potential intraoperative monitoring, the type of surgery is important when interpreting significance of changes of wave V. For non-cerebellopontine angle tumor surgery, hearing loss occurs usually only with permanent loss of wave V; much smaller changes may be important in cerebellopontine angle tumor surgery.

Approach Design and Closure Techniques to Minimize Cerebrospinal Fluid Leak after Cerebellopontine Angle Tumor Surgery

The purpose of the study was to identify specific aspects of surgical approach design and closure technique aimed at reducing the incidence of cerebrospinal fluid leak after cerebellopontine angle tumor surgery. Retrospective case review. Tertiary referral center. All patients undergoing cerebellopontine angle tumor surgery at the study institution from January 1996 through September 2004. The presence or absence of cerebrospinal fluid leak after various surgical approaches for a wide variety of cerebellopontine angle tumors. Three hundred forty three patients underwent surgery for cerebellopontine angle tumors at the study institution during the study period. Tumor types in descending order of frequency were as follows: acoustic neuroma, 244; cerebellopontine angle meningiomas, 33; petroclival meningiomas, 32; foramen magnum meningiomas, 10; epidermoid tumors, 9; facial nerve tumors, 6; hemangiopericytomas, 3; schwannomas of glossopharyngeal/spinal accessory nerves, 3; and unusual internal auditory canal tumors, 3. Surgical approaches used for tumor resection included translabyrinthine, retrosigmoid, combined transpetrosal, far lateral/transcondylar, middle cranial fossa, and extended middle cranial fossa. During the nearly 8-year study period, four postoperative cerebrospinal fluid leaks were encountered, resulting in a leak rate of 1.2%. Two of these patients required surgical repair of their leaks; the other two stopped spontaneously. The authors describe specific aspects of approach design and closure that appear to have a positive impact on postoperative cerebrospinal fluid leak rates. Attention to specific aspects of surgical approach design and wound closure results in a reduced incidence of cerebrospinal fluid leak after surgery for cerebellopontine angle tumors.

Effect of 17β-estradiol on diastrophic dysplasia sulfate transporter activity in otosclerotic bone cell cultures and SaOS-2 cells

Objective—Diastrophic dysplasia sulfate transporter (DTDST) is involved in the regulation of bone turnover, and its activity in otosclerosis has been shown to be abnormally high. Taking into account the role of estrogens in the progression of otosclerosis, the possible effect of estrogens on DTDST was investigated in otosclerotic bone cell cultures and in SaOS-2, a human osteoblastic cell line.Material and Methods—Primary bone cell cultures of stapes and external auditory canal (EAC) bone were obtained from 33 patients with otosclerosis and 18 control patients undergoing cerebellopontine angle tumor surgery. These cultures were assessed in parallel with SaOS-2 cells. Estrogen receptors (ERs) were detected using reverse transcriptase polymerase chain reaction. DTDST activity was assessed by sulfate uptake at baseline and after 24 h of incubation with 17β-estradiol at concentrations ranging from 10−12 to 10−6 M.Results—Stapes and EAC cultures predominantly expressed mRNA of ERα, while ERβ expression was predominant in SaOS-2 cells. In stapes and EAC cultures no modification of DTDST activity was observed with 10−8 M 17β-estradiol. In SaOS-2 cells, DTDST activity was inhibited by 17β-estradiol (93.5±9.21 vs 83.6±8.83 pmol/mg protein/5 min, n=29; mean of differences=10.0±3.22, paired t-test, p<0.01).Conclusion—DTDST activity is regulated by estrogens in SaOS-2 cells, but not in primary cell cultures from stapes and EAC. This difference in the regulation mechanisms may be related to the type of estrogen receptor expressed.

Acute Hearing Loss.

Acute hearing loss (AHL) is a medical urgency. The management of patients presenting with sudden deafness involves detecting the causal mechanism and administering emergency therapeutic drugs to restore hearing by minimizing the period of cellular ischemia to the inner ear. Acute management of AHL consists of administering a 10-day course of high-dose corticosteroids (prednisone 60 to 80 mg) until a cause can be established. Magnetic resonance imaging with gadolinium is indicated, with a study dedicated to the internal auditory canals. The natural history of idiopathic AHL is characterized by spontaneous improvement in two thirds of patients. Maximum improvement occurs within 2 weeks of onset of AHL. In the vast majority of patients (>90%), the AHL is idiopathic. For an identifiable etiology, the treatment is specific and may consist of stopping ototoxic medications, repair of perilymphatic fistulas, administering antimicrobial agents for viral or bacterial infections, correction of metabolic imbalances, management of stroke, and possible surgery for cerebellopontine angle tumors. Management of idiopathic AHL is controversial. Various therapeutic agents, such as vasodilators, diuretics, anticoagulants, plasma expanders, contrast agents, and carbogen inhalation, have been tried in single therapy or as a combination therapy. The empiric use of these drugs is mainly based on improving the blood circulation and restoring the oxygen tension to the inner ear. The use of interventional procedures, such as low-density lipoprotein apheresis as well as newer drug delivery systems for corticosteroids, and immunosuppressive agents have opened new options in the treatment of AHL secondary to immune-mediated diseases of the inner ear. Prognosis for AHL is best when patients are seen early, begin recovery within 2 weeks, and have a mild hearing loss (<90 dB) with upward-sloping audiograms. Greater than 90 dB of hearing loss along with flat or down sloping audiogram, advanced age, and presence of vertigo are adverse prognostic factors for recovery of hearing loss.