Large Cerebellopontine Angle Tumor Research Articles

Microsurgical Excision of Large Cerebellopontine Angle Tumors in Limited Resource Setting: Adapted Techniques and Operative Outcomes

Microsurgical Excision of Large Cerebellopontine Angle Tumors in Limited Resource Setting: Adapted Techniques and Operative Outcomes

Cochlear Obliteration after Translabyrinthine Resection for Large Cerebellopontine Angle Tumor

Introduction: The aim of this study was to better understand the onset time and factors associated with cochlear obliteration following translabyrinthine approach (TLA) surgery for large cerebellopontine angle tumors. Methods: This retrospective cohort study included 117 patients with large cerebellopontine angle tumor (tumor diameter >2 cm) treated by TLA surgery from June 2011 to March 2019 in a single tertiary referral center. The Kaplan-Meier method with log-rank test was used to estimate cochlear patency survival and the association between survival and covariates, and the Cox proportional hazards regression analysis was used to identify possible factors associated with cochlear obliteration. Results: Of the 117 patients included in our analysis, the median follow-up was 24.8 months. There were 30 (25.6%) patients in the cochlear obliteration group, and 87 (74.4%) in the patent cochlear group. Various degrees of cochlear obliteration was found in 25.6% patients in final MRI scan, comprised of 50% grade I, 30% grade II, and 20% grade III. Cochlear patency survival curves showed 94.0% at 3 months, 73.0% at 18 months, which plateaued after 20 months with a survival rate of 71.6%. In the multivariate Cox proportional hazards model, patients presented with postoperative hyperintense T1W cochlear signal had poorer cochlear patency survival compared to isointense T1W (HR = 4.15). Similarly, postoperative deteriorated facial function (HR = 4.52) and full IAC involvement of tumor (HR = 2.33) demonstrated a higher risks of cochlear obliteration after TLA surgery. Conclusion: The 2-year estimated cochlear patency rate was 71.6% in patients that received TLA. Cochlear obliteration can develop as early as 3 months post-surgery, with no new obliteration 20 months after the surgery and half of these patients got severe obliteration. Three factors associated with cochlear obliteration were identified including full IAC involvement of tumor, postoperative facial function deterioration, and postoperative hyperintense T1W cochlear signal.

Oculomotor Abnormalities in Large Cerebellopontine Angle Tumors: A Case Series of Bruns’ Nystagmus

Oculomotor Abnormalities in Large Cerebellopontine Angle Tumors: A Case Series of Bruns’ Nystagmus

The Combined TL-RS Approach: Advantages and Disadvantages of Working 360 Degrees around the Sigmoid Sinus.

Objective To highlight the advantages and disadvantages of the combined translabyrinthine (TL) and classic retrosigmoid (RS) approaches. Design Retrospective chart review. Setting National tertiary referral center for skull base pathology. Participants Twenty-two patients with very large cerebellopontine angle tumors were resected using the combined TL-RS approach. Main Outcome Measures Preoperative patient characteristics including age, sex, and hearing loss. Tumor characteristics, pathology, and size. Intraoperative outcome: tumor removal. Postoperative outcomes included facial nerve function, residual tumor growth, and neurological deficits. Results Thirteen patients had schwannoma, eight had meningioma, and one had both. The mean age was 47 years, mean tumor size was 39 × 32 × 35 mm (anterior-posterior, medial-lateral, craniocaudal), and mean follow-up period was 80 months. Tumor control was achieved in 13 patients (59%), and 9 (41%) had residual tumor growth that required additional treatment. Seventeen patients (77%) had postoperative House-Brackmann (H-B) facial nerve function grades I to II, one had H-B grade III, one H-B grade V, and three H-B grade VI. Conclusion Combining TL and RS approaches may be helpful in safely removing large meningiomas and schwannomas in selected cases. This valuable technique should be considered when sufficient exposure cannot be achieved with the TL or RS approach alone.

Impact of extent of internal acoustic meatus tumor removal using translabyrinthine approach for acoustic neuroma surgery

Many studies have investigated the surgical outcome and predictive factors of acoustic neuroma using different approaches. The present study focused on large tumors due to the greater likelihood of internal acoustic meatus involvement and the greater application of surgical intervention than radiosurgery. There have been no previous reports on outcomes of internal acoustic meatus tumor removal. We investigated the impact of the extent of internal acoustic meatus tumor removal using a translabyrinthine approach for large acoustic neuroma surgery and predictive factors of tumor control. This retrospective study reviewed 104 patients with large cerebellopontine angle tumor >3 cm treated by translabyrinthine approach microsurgery. Predictive factors of postoperative facial palsy, tumor control, and extent of internal acoustic meatus tumor removal were assessed. The mean tumor size was 38.95 ± 6.83 mm. Postoperative facial function showed 76.9% acceptable function (House-Brackmann grade 1 or 2) six months after surgery. The extent of internal acoustic meatus tumor removal was a statistically significant predictor factor of poor postoperative facial function. Younger age, larger tumor size needing radiosurgery, and more extensive removal of tumor were associated with better tumor control. More extensive internal acoustic meatus tumor removal was associated with poor postoperative facial function and better tumor control.

Ocular Tilt Reaction in Compensated Vestibular Schwannoma

Ocular Tilt Reaction in Compensated Vestibular Schwannoma

Early-Career Surgical Practice for Cerebellopontine Angle Tumors in the Era of Radiosurgery.

We analyzed the outcomes of patients with large cerebellopontine angle (CPA) tumors treated by a skull-base team in which two surgeons (one neurosurgeon and one otological surgeon) were in the beginning of their careers (<40 years old). Data of patients operated on between April 2012 and March 2016 were reviewed. All factors related to surgical training were considered. Thirty-one patients had vestibular schwannomas, while 26 had meningiomas. Mean tumor diameter was 30.6 mm (range, 23-49 mm) for schwannomas and 35 mm (range, 22-51 mm) for meningiomas. Satisfactory postoperative facial nerve function (House-Brackmann's grade I or II) was achieved in 20 (64.5%) schwannoma patients and 21 (80.7%) meningioma patients. Gross total and near-total resections (residual tumor < 5 mm) were achieved in 21 (67.7%) and 9 (29%) schwannoma patients, respectively. Gross total resection (Simpson's grade II) was achieved in 18 (69.2%) meningioma patients. In both groups, the retrosigmoid approach was the most common approach. Regarding surgical training of the two younger surgeons, during the residency period, they attended high-volume centers for CPA tumors. Application of microsurgical techniques was systematically applied from the beginning of their personal series in every intracranial pathology case. During the first 2 years of the series, they were supervised by more experienced surgeons and followed a stepwise sharing of increasingly difficult surgical phases; by comparing results of this period with the last 2 years of the series, where they acquired a complete autonomy, no relevant difference was detected. Our results suggest that young surgeons may achieve good results even at the beginning of their careers, if specific conditions related to training and mentorship are met.

Hypervascular Lesions of the Cerebellopontine Angle: The Relevance of Angiography as a Diagnostic and Therapeutic Tool and the Role of Stereotactic Radiosurgery in Management. A Comprehensive Review

The cerebellopontine angle (CPA) is a narrowed skull base area containing important cranial nerves and vessels and bordering with eloquent areas of the posterior fossa. Tumors of the CPA are a heterogeneous group and can have extradural, intradural/extra-axial, or intra-axial origins. Their vascular supply changes depending on their anatomic origin. Symptomatic, large CPA tumors require surgical resection in order to prevent irreversible, severe neurological damages. However, its tight and strategical location make surgery in the CPA very challenging and require appropriate pre-surgical planning. Pre-surgical diagnosis is of great importance as it allows us to choose the optimal management for the particular patient. This is of further significance when encountering high-risk lesions such as hypervascular tumors. Neurosurgeons should utilize every available pre-surgical diagnostic modalities as well as neo-adjuvant treatments in order to reduce such risks. We review all reported cases of hypervascular lesions of the CPA and discuss the roles of angiography and stereotactic radiosurgery in their management. Three lesions of the CPA can be considered as truly hypervascular: hemangioblastomas, hemangiopericytomas and paragangliomas. All lesions share many radiological features. However, each lesion has a different anatomical origin and hence, has a characteristic vascular supply. Pre-surgical angiography can be utilized as a diagnostic tool to narrow down the differential diagnosis of a vascular CPA lesion, based on the predominant supplying vessel. In addition, pre-surgical embolization at time of angiography will narrow the associated surgical risks. Angiography is a crucial diagnostic and therapeutic tool, helping both in narrowing the presurgical differential diagnosis and in controlling intraoperative bleeding. Because of the high surgical risks associated with resection of vascular tumors in the CPA, noninvasive treatments, such as stereotactic radiosurgery, also may have a crucial role.

Translabyrinthine resection of neurofibromatosis type 2 associated vestibular and facial schwannomas, repair of facial nerve, and placement of auditory brainstem implant

We present video of gross-total resection of a large cerebellopontine angle tumor consisting of both vestibular and facial schwannoma components via the translabyrinthine route in a patient with neurofibromatosis type 2. The facial nerve is reconstructed using a greater auricular nerve graft, and an auditory brainstem implant is placed. Prior to surgery the patient had no facial nerve function on the operative side and had lost useful hearing. He also had usable vision only on the ipsilateral side and had contralateral vocal cord paralysis. The video can be found here: http://youtu.be/IOkEND-0vhI .

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.

Preoperative identification of the facial nerve in patients with large cerebellopontine angle tumors using high-density diffusion tensor imaging

Facial nerve paresis can be a devastating complication following resection of large (> 2.5 cm) cerebellopontine angle (CPA) tumors. The authors have developed and used a new high-density diffusion tensor imaging (HD-DT imaging) method, aimed at preoperatively identifying the location and course of the facial nerve in relation to large CPA tumors. Their study objective was to preoperatively identify the facial nerve in patients with large CPA tumors and compare their HD-DT imaging method with a traditional standard DT imaging method and correlate with intraoperative findings. The authors prospectively studied 5 patients with large (> 2.5 cm) CPA tumors. All patients underwent preoperative traditional standard- and HD-DT imaging. Imaging results were correlated with intraoperative findings. Utilizing their HD-DT imaging method, the authors positively identified the location and course of the facial nerve in all patients. In contrast, using a standard DT imaging method, the authors were unable to identify the facial nerve in 4 of the 5 patients. The HD-DT imaging method that the authors describe and use has proven to be a powerful, accurate, and rapid method for preoperatively identifying the facial nerve in relation to large CPA tumors. Routine integration of HD-DT imaging in preoperative planning for CPA tumor resection could lead to improved facial nerve preservation.

Cerebellopontine angle subependymoma without fourth ventricle extension: An uncommon tumor in a rare location

Subependymomas are benign tumors that occur predominantly in the ventricular system. We describe a case of a 57-year-old man with a large cerebellopontine angle (CPA) tumor which expanded into the jugular foramen. Complete surgical excision of the tumor was achieved through a retrosigmoid approach and the histopathological diagnosis was subependymoma. Subependymomas located exclusively in the CPA without extension into the fourth ventricle are extremely rare. The mainly pathological features and the difficulty in correctly diagnosing these cases preoperatively, even with MRI, are discussed.

Hearing Improvement after Resection of a Large Jugular Foramen Schwannoma: Case Report and Proposed Mechanism

Introduction: Although hearing improvement after surgery for small tumors of the cerebellopontine angle has been previously reported, the mechanism by which surgery leads to an improvement in hearing remains obscure. We report on a patient who was found to have a large (5 cm) cerebellopontine angle tumor originating from rootlets of cranial nerve X at the jugular foramen who experienced significant hearing improvement after surgery.

High jugular bulb in the translabyrinthine approach to the cerebellopontine angle: anatomical considerations and surgical management

Evidence of a high jugular bulb position (HJBP) during the translabyrinthine approach may compromise the surgical removal of cerebellopontine angle (CPA) tumours. We report a simple surgical procedure to safely manage this frequent normal variation and comment on various alternative options. The translabyrinthine approach included a complete skeletonization of the sigmoid sinus and of the presigmoid dura. A thin eggshell bone was left at the jugular bulb surface. The dome of the jugular bulb was gently dissected from the jugular fossa and gradually retracted downward in a tailored way, allowing the surgeon to drill below the internal auditory meatus. A small piece of bone was wedged over the jugular dome in order to maintain its lowered position. Among 178 consecutive translabyrinthine approaches performed for the removal of large CPA tumors, the use of this procedure was required in 44 cases of HJBP. Excepting minimal venous bleeding easily controlled in several cases, we never observed any complication from this procedure nor failure to expose the inferior compartment of the CPA. The HJBP can be systematically diagnosed with the preoperative CT-scan using bone window imaging. Our results demonstrate that the described procedure is safe and effective to widen the operative corridor that is required for the exposure of the inferior compartment of the CPA in this anatomical situation.

Akustikusneurinom als Ursache einer progredienten kindlichen Hörstörung

Neurinomas of the vestibulocochlear nerve unrelated to neurofibromatosis in children are extremely rare. Only 20 cases in children under the age of 16 are reported in the literature. Progressive unilateral hearing loss, tinnitus, vertigo and neurological deficits due to cranial nerve or brainstem compression are clinical signs. We report on the case of a 12-years-old girl with an unilateral hearing loss, progressing to total deafness. Otoacoustic emissions were normal. In the MRI a large cerebellopontine angle tumor was found, identified as schwannoma of the vestibulocochlear nerve. The importance of MR Imaging in children with progressive unilateral hearing loss is demonstrated in this case.

平衡機能検査で異常所見に乏しかった大きな小脳橋角部腫よう症例

Most large cerebello-pontine angle (CPA) tumors usually cause typical abnormal oculomotor findings on vestibular and oculomotor examinations, reflecting brainstem and cerebellar lesions. However, we encountered four patients with large CPA tumor without the typical abnormal neurotological findings and these cases are described in this report. Case 1 : A 63-year-old female. Chief compliment (CC) was double vision. Audiovestibular examinations showed normal findings except for slight nystagmus on ENG. MRI revealed a 4.8 × 4.7 cm lesion of the right CPA. The histopathological diagnosis was CPA meningioma.Case 2 : A 58-year-old female. CC was a tinnitus. Pure tone audiometry indicated right-sided sensorineural hearing loss (SNHL). Results of vestibular examination were normal. MRI revealed a 4.0 × 3.5 cm lesion from the clivus to the CPA that was diagnosed radiologically as a meningioma. Case 3 : A 50-year-old female. CC were tinnitus and head heaviness. Audiovestibular examinations were all unremarkable. MRI revealed a 3.0 × 2.7 cm lesion of the right CPA that was diagnosed as an epidermoid cyst. Case 4 : A 48-year-old female. CC were hearing loss and tinnitus. Audiometric studies indicated right-sided moderate-to-profound SNHL. There were no responses on ABR. Vestibular examinations were unremarkable. MRI revealed a 4.2 × 4.0 cm left-sided CPA mass that was diagnosed at surgery as an acoustic neuroma with cystic changes. Previous study showed that when the CPA tumor is larger than 3 cm, ETT and OKP demonstrate abnormal findings in 70 to 78% of patients, respectively. However, in our cases, despite pronounced compressions of the brainstem and cerebellum by large CPA tumors, vestibular examinations did not reveal any significant findings. These atypical findings might have resulted from the histological characteristics and slow growth of the CPA tomor, in addition to factors related to central vestibular compensation and indivisual differences in susceptibility to the lesions.

Airway Obstruction After Ventriculoperitoneal Shunt Insertion in a Patient with Neurofibromatosis

Airway Obstruction After Ventriculoperitoneal Shunt Insertion in a Patient with Neurofibromatosis

Delayed Diagnosis of Large Cerebellopontine Angle Tumors, Despite Hearing Conservation Training

Recently, at the National Naval Medical Center in Bethesda, Maryland, we have encountered several patients with large cerebello-pontine angle tumors. All were active duty and had evaded the military's stringent hearing screening program until the tumors were of life-threatening size. Early detection of these tumors can reduce overall morbidity and improve the patient's chances of returning to a normal lifestyle. We have analyzed each of these cases and discovered weaknesses in the program. The primary difficulty was in accurately following the algorithms set forth by military regulations. To that end we recommend: (1) establishing a cutoff for identification of those who should be evaluated after they obtain their enlistment/annual physical examinations; (2) specific training for hearing conservation program managers in the algorithms for hearing screening; (3) establishment of specific guidelines for primary care physicians for further evaluation of abnormal audiograms; and (4) reevaluation of form DD 2216.

聴力正常の小脳橋角部大腫ようの２症例

Two patients with large cerebellopontine (CP) angle tumors and normal pure-tone hearing levels are reported. Case 1, a 49-year-old woman, first experienced hearing distortion in her left ear. Case 2, a 45-year-old woman, first experienced numbness at the tip of her tongue, and then noted hearing loss in the left ear. However, their pure-tone audiograms were normal. In both cases, the Bekesy audiogram showed a type III tracing for the left ear, and the results of auditory brainstem response (ABR) testing were abnormal. A CT scan and a MR imaging demonstrated a CP angle tumor of 6×4 cm size in Case 1, and of 3.5×3 cm size in Case 2. The former was a surgically confirmed CP angle meningioma, and the latter was a surgically suspected facial nerve neuroma. These cases emphasize the fact that a large CP angle tumor can be present without affec-ting pure-tone hearing sensitivity. The clinician must be aware that a subjective hearing impair-ment may be the only clues to the presence of a CP angle tumor. ABR is a valuable procedure for detecting CP angles tumors in patients with normal pure-tone hearing.

The Disconnected Ear

To document the existence of a peripheral auditory disconnection syndrome in a 23-yr-old male with a large tumor of the right cerebellopontine angle using contemporary behavioral, electroacoustic, and electrophysiologic auditory tests. Single subject with repeated measures. In spite of a profound hearing loss in an ear with a large cerebellopontine angle tumor determined by behavioral audiometry, distortion product otoacoustic emissions, surface recorded brain stem auditory evoked potentials, and transtympanic electrocochleography (click evoked compound action potentials and tone evoked cochlear microphonics) demonstrated that the cochlea was intact and functional over a broad bandwidth and intensity range. A peripheral auditory disconnection syndrome is demonstrated in a 23-yr-old male with a large tumor of the cerebellopontine angle. In this instance, the tumor effectively deafferentated the peripheral from central auditory nervous system, resulting in profound hearing loss of presumed neural origin. It is suggested that other pathologic conditions/mechanisms could produce similar findings.