Acupuncture for rehabilitation after surgery for cerebellopontine angle meningioma: A case report.

RATIONALE: In some cases, surgery of cerebellopontine angle meningioma (CPAM) might result in multiple cranial nerve injury, which could bring serious impact on the patients, especially when it affects the function of facial muscles and eyeballs. This report describes a successful application of acupuncture for rehabilitation in a patient after surgery for CPAM. PATIENT CONCERNS: A 27-year-old patient presented with limitation of left eye abduction, accompanied with frontal and facial sensory disturbance on the left after resection of the pontocerebellar angle tumor. The patient also suffered from significant anxiety and depression as concomitant symptoms. DIAGNOSES: Based on medical history, clinical symptoms, and magnetic resonance imaging results, the patient was diagnosed with the fourth, fifth, sixth, and seventh cranial nerve injury after surgery for CPAM. INTERVENTIONS: Acupuncture treatment was applied for this patient. One acupuncture session was given every 2 days in 35 days, and the needles were retained for 30 minutes per session. OUTCOMES: After acupuncture treatment, the limitation of left eye abduction had totally recovered. The superficial sensory disturbance in the frontal and facial region was significantly relived. Besides, the scores of Hamilton Anxiety and Depression Scale showed a significant reduction. However, the superficial sensory of the alar and nasolabial groove on the left side still decreased mildly when compared with the right side. CONCLUSION: Acupuncture might be an option for rehabilitation after surgery for CPAM.

Intraoperative Auditory System Monitoring.

A new electrophysiological system for intraoperative, continuous, near-real time monitoring of cochlear nerve function through acoustic stimulation in the ear canal and recording of the evoked dorsal cochlear nucleus potentials (DNAPs) by a specially designed DNAP electrode placed directly on the brainstem is described. The system is denominated "(cerebellopontine angle) CPA Master" and is designed for hearing preservation surgery in the cerebello-pontine angle, through the retro-sigmoid or the retro-labyrinthine approach. As an additional novelty within the field, the system allows intraoperative mapping and thus precise localization of the cochlear nerve in its entire trajectory from the brainstem to the fundus of the internal auditory canal, which is a major advance in relation to atraumatic dissection of the nerve. The system can be used for surgery of all types of CPA tumors, for example, vestibular schwannomas, meningiomas and epidermoid cysts, but also for vestibular nerve section and vascular decompression. The system also allows evaluation of the electrical functionality of an anatomically intact cochlear nerve in translabyrinthine surgery, thus predicting the benefit of optional cochlear implantation.

CE-Chirp® ABR in cerebellopontine angle surgery neuromonitoring: technical assessment in four cases.

Continuous monitoring of wave V of auditory brainstem response (ABR), also called brainstem auditory evoked potential (BAEP), is the most common method used in intraoperative neuromonitoring (IONM) functionality of cochlear nerve during surgery in cerebellopontine angle (CPA). CE-Chirp® ABR represents a recent development of classical ABR. CE-Chirp® is a new acoustic stimulus used in newborn hearing testing, designed to provide enhanced neural synchronicity and faster detection of larger amplitude wave V. In four cases, CE-Chirp® ABR was performed during cerebellopontine angle (CPA) surgery. CE-Chirp® ABR represented a safe and effective method in neuromonitoring functionality of vestibulocochlear nerve. A faster neuromonitoring feedback to surgical equipe was possible with CE-Chirp ABR®.

Contralateral hearing loss after vestibular schwannoma excision: a rare complication of neurotologic surgery.

We report a rare case of contralateral hearing loss after vestibular schwannoma excision in a 48-year-old man who underwent surgery via a suboccipital approach for removal of a nearly 2-cm lesion involving the right cerebellopontine angle. Postoperatively, the patient awoke with bilateral deafness, confirmed by both audiometry and spontaneous otoacoustic emissions. The patient was treated aggressively with high-dose intravenous steroids, vitamins E and C, and oxygen. Over the next several months he had gradual recovery of most of the hearing in his left (unoperated) ear. Contralateral hearing loss may develop after vestibular schwannoma excision; multiple pathophysiologic mechanisms for this occurrence have been proposed.

Síndrome constitucional como presentación de meningioma pontocerebeloso / Constitutional syndrome as a presentation of a cerebellopontine meningioma

Los meningiomas son tumoraciones eminentemente benignas procedentes de las meninges, correspondiendo al 15-25% de las tumoraciones intracraneales en el adulto, cuya expresividad clínica viene representada por la compresión de estructuras vecinas quedando representada predominantemente por cefalea, alteraciones del comportamiento, y déficit neurológicos. Presentamos un caso donde el cuadro constitucional constituye la primera y principal manifestación de un meningioma intracraneal pontocerebeloso (AU)

Meningiomas are basically benign tumours arising in the meninges and account for 15-25% of intracranial tumours in adults. It is clinically signs are due to compression of the neighbouring structures, with the main symptoms being migraine, behavioural changes, and neurological deficits. We present a case where constitutional syndrome was the first and principal manifestation of an intracranial cerebellopontine meningioma (AU)

Ganglioglioma in Brainstem : Case Report and a Review of Literatures

Ganglioglioma is an infrequent tumor of the central nervous system (CNS); mostly supratentorial region. But, they can occur anywhere in the central nervous system such as brainstem, cerebellopontine angle (CPA), thalamus, optic nerve and spinal cord. Although it occurs rarely, ganglioglioma should be included in the differential diagnosis of a posterior fossa mass because early recognition is important for treatment and patient counseling.

Motor cortex stimulation in a three-year-old child with trigeminal neuropathic pain caused by a malignant glioma in the cerebellopontine angle: case report.

BACKGROUND AND IMPORTANCE: Motor cortex stimulation (MCS) is an accepted treatment in neuropathic pain syndromes. Use of MCS for trigeminal neuropathic pain (TNP) caused by a malignant glioma or in a child has not previously been reported in the literature. CLINICAL PRESENTATION: A 3-year-old boy presented to our department with a right temporal tumor with extension into the cavernous sinus and along the root of the trigeminal nerve up to the protuberance. Six weeks after removal of the temporal part of the tumor, the patient developed medically refractory trigeminal pain associated with tumor progression into the posterior fossa. We decided to remove the tumor from the cerebellopontine angle and residual tumor in the pericavernous area and then gave postoperative radio- and chemotherapy. Five months later, the patient developed unbearable refractory neuropathic pain characterized by a burning sensation in the first and second trigeminal areas. After a multidisciplinary discussion, MCS was recommended. We performed subdural MCS after localization of the central sulcus via anatomic landmarks, neuronavigation, peroperative sensory evoked potentials, and motor evoked potentials. The mother estimated a 75% reduction in the child's pain at 48 hours postoperatively, which continued until the child was pain-free. CONCLUSION: MCS is a minimally invasive surgical technique that seems to be a potential treatment for carefully selected children experiencing very severe and medically refractory neuropathic pain, even in the context of a neoplasm.

An anatomical assessment of the supracerebellar midline and paramedian approaches to the inferior colliculus for auditory midbrain implants using a neuronavigation model on cadaveric specimens.

The inferior colliculus (IC) is an alternative site for electrode placement in neural deafness due to its surgical accessibility and its well-known tonotopic stratification. In patients where tumor surgery has already occurred and the cerebellopontine angle contains scar tissue or tumor-remnants, midline and paramedian supracerebellar approaches are alternative routes. They are often avoided due to concerns regarding the venous drainage of the cerebellum, the electrode trajectory and the course of the electrode cable. We studied these surgical routes in five neuronavigated fixed cadaveric specimens. For paramedian and midline approaches, the transverse sinus was exposed 5.8mm on average. A mean of 1.6 cerebellar veins, with an average diameter of 2.0mm, draining to the tentorium were transected to reach the tentorial notch. Only 0.4 arterial branches were met. We conclude that the supracerebellar midline and paramedian approaches provide a good exposure of the IC and offer safe and viable alternative routes to the IC. Additionally, they provide a wider angle of action for optimal electrode placement.

A case of cerebellopontine angle meningioma presenting with neck and upper extremity pain.

OBJECTIVE: The purpose of this case report is to describe and discuss the clinical presentation, diagnosis, and management of a patient with a cerebellopontine angle meningioma. CLINICAL FEATURES: A 29-year-old man presented to a chiropractor with diffuse musculoskeletal pain in the neck and right upper extremity. The findings of the clinical examination included a unilateral lower cranial nerve motor deficit. INTERVENTION AND OUTCOME: Magnetic resonance imaging studies of the neck and brain revealed a posterior fossa tumor, which was eventually diagnosed as a benign meningioma. Partial surgical removal of the tumor mass was followed by radiation therapy. Postoperative morbidity was fairly low. Lower cranial nerve function normalized after surgery. CONCLUSION: Patients with brain lesions may present to chiropractic practices with predominantly musculoskeletal symptoms. Chiropractors can aid in the multidisciplinary and integrated management of such conditions through careful interviewing and appropriate neurological examination.

[Usefulness of hyperbaric oxygen in the treatment of radionecrosis and symptomatic brain edema after LINAC radiosurgery]. / Eficacia del oxígeno hiperbárico en el tratamiento de la radionecrosis y el edemacerebral sintomáticos tras radiocirugía con acelerador lineal.

Radionecrosis with brain edema is a complication of radiosurgery. Three female patients harbouring a frontal pole, petrous and parasagital parietoocipital meningiomas respectively who had been treated with LINAC radiosurgery are presented. Those patients developed, between two and eight months later, a severe symptomatic radionecrosis with a huge brain edema resistant to the usual steroid therapy. Only after 40 sessions of hyperbaric oxygen, a good remission of the lesions was obtained. There are few cases reported in the literature with such a good outcome. Consequentely, this therapy must be taken into account to treat this type of radiosurgical complication before considering surgery.

Eficacia del oxígeno hiperbárico en el tratamiento de la radionecrosis y el edemacerebral sintomáticos tras radiocirugía con acelerador lineal / Usefulness of hyperbaric oxygen in the treatment of radionecrosis and symptomatic brain edema after LINAC radiosurgery

La radio necrosis y el edema cerebral son complicaciones asociadas a la radiocirugía. Presentamos los casos de tres pacientes tratadas con radiocirugía mediante acelerador lineal, de un meningioma de polo frontal izquierdo, peñasco y para sagital parietooccipital, respectivamente, que desarrollaron, entre dos y ocho meses más tarde, lesiones de tipo radio necrótico con extenso edema peritumoral que resultaron resistentes al tratamiento con esteroides y que se han resuelto con la administración de 40 sesiones de oxígeno hiperbárico. Son pocos los casos publicados hasta ahora en la literatura con tan excelentes resultados, por lo que consideramos un hecho a tener muy en cuenta ante las posibles complicaciones de este tipo que puedan presentarse en el transcurso de la práctica radioquirúrgica antes de recurrir a la cirugía (AU)

Radionecrosis with brain edema is a complication of radiosurgery. Three female patients harbouring a frontal pole, petrous and parasagital parietoocipital meningiomas respectively who had been treated with LINAC radiosurgery are presented. Those patients developed, between two and eight months later, a severe symptomatic radionecrosis with a huge brain edema resistant to the usual steroid therapy. Only after 40 sessions of hyperbaric oxygen, a good remission of the lesions was obtained. There are few cases reported in the literature with such a good outcome. Consequentely, this therapy must be taken into account to treat this type of radiosurgical complication before considering surgery (AU)

Neurophysiological mechanisms of conduction impairment of the auditory nerve during cerebellopontine angle surgery.

OBJECTIVE: Intraoperative auditory brainstem response (ABR)-monitoring is useful for hearing preservation in patients undergoing cerebellopontine angle surgery. Prolongation of the latency of wave V, for example, is observed under surgical stress such as cerebellar retraction. We analyzed intraoperative ABR findings to study the neurophysiological mechanism(s) underlying latency prolongation. METHODS: The ABR recorded during microvascular decompression surgery was studied in 18 patients with hemifacial spasm. We measured each trace of the ABR records, both the latency of each wave and some interpeak latencies. We also analyzed their waveforms especially in the early component, to assess changes during surgery. RESULTS: The latency of wave V varied with cerebellar retraction. The delayed latency of wave V was correlated with the prolonged interpeak latency of waves I-III. An additional wave (designated wave I') between waves I and II was appeared; it was accompanied by a prolongation in the latency of wave V. Wave I' contributed to prolongation of the interpeak latency of waves I-III, resulting in a delay in the latency of wave V. Chronological analysis revealed that the minimum latency of wave I' was the same as wave IN, suggesting that wave I' arose near the porus acusticus internus (PAI). CONCLUSION: Our study showed that cerebellar retraction may result in conduction impairment of the auditory nerve near the PAI, suggesting that the Obersteiner-Redlich zone is an electrophysiologically vulnerable site and wave I' is derived from the change in the vector of wave IN. SIGNIFICANCE: Our findings may provide neurophysiological evidence to support the theoretical model of ABR generators by Scherg and von Cramon.

Hemifacial Spasm Caused by Epidermoid Tumor at Cerebello Pontine Angle

Hemifacial spasm (HFS) is almost always induced by vascular compression but in some cases the cause of HFS are tumors at cerebellopontine angle (CPA) or vascular malformations. We present a rare case of hemifacial spasm caused by epidermoid tumors and the possible pathogenesis of HFS is discussed. A 36-year-old female patient presented with a 27-month history of progressive involuntary facial twitching and had been treated with acupuncture and herb medication. On imaging study, a mass lesion was seen at right CPA. Microvascular decompression combined with mass removal was undertaken through retrosigmoid approach. The lesion was avascular mass and diagnosed with an epidermoid tumor pathologically. Eventually, we found a offending vessel (AICA : anterior inferior cerebellar artery) compressing facial nerve root exit zone (REZ). In case of HFS caused by tumor compression on the facial nerve REZ, surgeons should try to find an offending vessel under the mass. This case supports the vascular compression theory as a pathogenesis of HFS.

Intraoperative monitoring of hearing during cerebellopontine angle tumor surgery using transtympanic electrocochleography.

OBJECTIVE: To investigate the use of transtympanic electrocochleography (TT-ECochG) analyzed on-line by a detector strategy software that made possible automatic extraction of TT-ECochG components intraoperatively in real-time domain. PATIENTS: Fifteen patients with cerebellopontine angle tumor among 50 patients were included in this study. INTERVENTION: All subjects were operated on via middle fossa or retrosigmoid approach. Pure-tone average (PTA) was measured at 0.5, 1.0, and 2.0 kHz, and calculations were performed before and after surgery. Auditory function was monitored intraoperatively via TT-ECochG, and analyzed data were displayed on-line. MAIN OUTCOME MEASURES: TT-ECochG changes in morphology were described. Postoperative PTA elevation level correlated with TT-ECochG morphology changes occurring intraoperatively. RESULTS: Analyzed on-line, TT-ECochG data were displayed as first negative peak of compound action potential amplitude and latency in time domain every 3 to 5 seconds. A good correlation between postoperative PTA elevation and TT-ECochG morphology changes was showed (Spearman rank test, R = +0.93; t(N-2) = 9.00; p < 0.0001). CONCLUSION: TT-EcochG seemed to effectively mirror even minimal changes in auditory function during intraoperative monitoring in real-time domain. Developed strategy of on-line analysis makes the intraoperative hearing status assessment faster and easier.

The influence of unilateral versus bilateral clicks on the vestibular-evoked myogenic potentials.

OBJECTIVE: Because a continuous muscular effort is required during recording of vestibular-evoked myogenic potentials, we assume vestibular-evoked myogenic potentials elicited by simultaneous bilateral clicks can be used as a more convenient mode compared with respective unilateral clicks. To investigate whether bilateral clicks provide the same information as unilateral clicks, we examined whether the responses are different between them in normal subjects and whether bilateral clicks have the same diagnostic value as vestibular-evoked myogenic potentials elicited by unilateral clicks in detecting retrolabyrinthine lesions. STUDY DESIGN: Prospective study. SETTING: Academic tertiary referral center. SUBJECTS: Fourteen healthy volunteers and four patients with unilateral cerebellopontine angle tumors were enrolled in this study. INTERVENTIONS: Recordings of vestibular-evoked myogenic potential responses. MAIN OUTCOME MEASURES: The latency of each peak (p13, n23), the peak-to-peak interval, and amplitude (p13-n23). RESULTS: Both unilateral and bilateral click stimulation of 28 ears (100%) produced vestibular-evoked myogenic potentials in normal subjects. The mean latencies of p13 and n23, peak-to-peak interval, and amplitude of vestibular-evoked myogenic potentials elicited with unilateral clicks were 11.62 +/- 0.99 ms, 19.74 +/- 1.30 ms, 8.12 +/- 1.66 ms, and 110.79 +/- 61.37 microV, respectively, whereas those elicited with bilateral clicks were 11.16 +/- 0.51 ms, 19.22 +/- 1.61 ms, 8.06 +/- 1.66 ms, and 111.77 +/- 40.98 microV, respectively. There was a significant difference (p < 0.05) in the latencies, but not for the interval and amplitude (p > 0.05). Four patients with unilateral cerebellopontine angle tumors and prolonged latencies of unilateral clicks vestibular-evoked myogenic potentials also showed latency prolongation in bilateral clicks vestibular-evoked myogenic potentials. CONCLUSION: Although the use of bilateral acoustic stimulation shortens the vestibular-evoked myogenic potential latencies in normal subjects, it does not affect the bilateral clicks vestibular-evoked myogenic potential ability to detect retrolabyrinthine lesions. Bilateral clicks vestibular-evoked myogenic potentials are a more convenient mode with which to help diagnose both labyrinthine and retrolabyrinthine lesions than unilateral clicks vestibular-evoked myogenic potentials.

[Spectral analysis of the ECG R-R interval permits early detection of vagal responses to neurosurgical stimuli]. / L'analyse spectrale de l'intervalle R-R de l'ECG permet la détection précoce des réponses vagales aux stimuli neurochirurgicaux.

OBJECTIVE: To assess the efficacy of ECG spectral analysis, compared with heart rate (HR) monitoring in the detection of vagal response to surgical stimuli. METHODS: Twenty Asa II-III patients (age: 65 +/- 13 years) scheduled for surgery of cerebellopontine angle or implantation of sacral root stimulator were examined. Target controlled infusion of propofol (2-4 microg x ml(-1)) and remifentanil (4 ng x ml(-1)) was guided by the bispectral index (Bis). Arterial pressure via a radial catheter, pulse oximetry and end tidal CO2 were continuously monitored. Spectral analysis was achieved by connecting a computer to the cardiorespiratory monitor. Online power spectrum densities were calculated from the ECG R-R interval by software based on the fast Fourier transform (LabView, National Instruments, USA). Low frequency (LF: 0.04-0.15Hz) and high frequency (HF: 0.15-0.4Hz) were associated with sympathetic and parasympathetic activities respectively. We defined vagal reaction as a decrease in FC or an increase in HF >10% of the prestimuli value. HF and FC were compared according to the detection delay (by a Student t test with p < 0.05 considered significant) and a concordance test with a kappa coefficient (kappa): -1 = total discordance to 1 = total concordance. RESULTS: Twelve vagal reactions (observed in 8 patients) were detected within 5.5 +/- 1.3 s (HF) and 12.4 +/- 1.6 (FC); p < 0.001. Concordance between the 2 parameters was 95% (kappa =0.9). CONCLUSION: The ECG spectral analysis is a non-invasive technique, which permits the detection of intra-operative vagal reactions earlier than conventional monitoring of HR.

Contralateral suppression of transient evoked otoacoustic emissions in patients with cerebello-pontine angle tumor.

OBJECTIVE: During measurement of transient evoked otoacoustic emissions (TEOAEs), acoustic stimulation of the contralateral ear reduces or suppresses TEOAE amplitude. This is thought to be due to the inhibitory control that the medial efferent auditory nerve exerts on outer hair cell (OHC) function. The main aim of this study was to investigate the effect of cerebello-pontine angle (CPA) tumor on the medial efferent nerve pathways to both tumor and non-tumor ears by examining alterations in TEOAE amplitude that result from contralateral acoustic stimulation. DESIGN: Contralateral suppression of TEOAEs using broadband noise was measured preoperatively in 17 patients with unilateral CPA tumor and 17 normally hearing controls, matched for age and gender. RESULTS: The control ears demonstrated significantly more suppression than the tumor and non-tumor ears in the patient group. There was, however, no significant difference in suppression between the tumor and non-tumor ears, and the statistical correlation for suppression between them was high. There was no effect of gender, hearing threshold levels, or size and type of tumor on suppression, although there was an effect of age on suppression in both the control and patient groups where suppression reduced as age increased. Four of the 17 patients had TEOAEs, which were clearly present in the tumor ear despite substantial hearing loss, three of which had no measurable hearing. CONCLUSIONS: It is hypothesized that neural compression by CPA tumor disrupts the medial efferent nerve control mechanism to the OHCs of tumor ears. It also is hypothesized that neural compression reduces transmission of afferent nerve impulses from the tumor ear, which cross over to the medial olivo-cochlear complex and reduce the inhibitory control of OHC function in the non-tumor cochlea.

Brainstem electronic implants for bilateral anacusis following surgical removal of cerebello pontine angle lesions.

The multichannel auditory brainstem implant (ABI) has been used successfully to treat deafness in individuals with neurofibromatosis type II. The device has been implanted in nearly 150 recipients worldwide, and clinical trials with the device are approaching completion. The implantation and fitting of the multichannel ABI differ significantly from cochlear implantation, and the processes are illustrated in a series of case studies. Performance data also are included from recipients with up to 7 years experience.