Preservation Of Cranial Nerve Function Research Articles

Preservation of cranial nerve function in large and giant trigeminal schwannoma resection: a case series.

Trigeminal schwannomas (TSs) are intracranial tumors that can cause significant brainstem compression. TS resection can be challenging because of the risk of new neurologic and cranial nerve deficits, especially with large (≥ 3cm) or giant (≥ 4cm) TSs. As prior surgical series include TSs of all sizes, we herein present our clinical experience treating large and giant TSs via microsurgical resection. This was a retrospective, single-surgeon case series of adult patients with large or giant TSs treated with microsurgery in 2012-2023. Seven patients underwent microsurgical resection for TSs (1 large, 6 giant; 4 males; mean age 39 ± 14years). Tumors were classified as type M (middle fossa in the interdural space; 1 case, 14%), type ME (middle fossa with extracranial extension; 3 cases, 43%), type MP (middle and posterior fossae; 2 cases, 29%), or type MPE (middle/posterior fossae and extracranial space; 1 case, 14%). Six patients were treated with a frontotemporal approach (combined with transmastoid craniotomy in the same sitting in one patient and a delayed transmaxillary approach in another), and one patient was treated using an orbitofrontotemporal approach. Gross total resection was achieved in 5 cases (2 near-total resections). Five patients had preoperative facial numbness, and 6 had immediate postoperative facial numbness, including two with worsened or new symptoms. Two patients (28%) demonstrated new non-trigeminal cranial nerve deficits over mean follow-up of 22months. Overall, 80% of patients with preoperative facial numbness and 83% with facial numbness at any point experienced improvement or resolution during their postoperative course. All patients with preoperative or new postoperative non-trigeminal tumor-related cranial nerve deficits (4/4) experienced improvement or resolution on follow-up. One patient experienced tumor recurrence that has been managed conservatively. Microsurgical resection of large or giant TSs can be performed with low morbidity and excellent long-term cranial nerve function.

Recurrences and progression following microsurgery of vestibular schwannoma.

The treatment approach of vestibular schwannoma (VS) has seen a change in recent years, with a trend away from radical surgery towards preservation of cranial nerve function. A recent study reported recurrences as long as 20 years after complete removal of VS. To report the risk of recurrence and progression in our patient population the authors retrospectively reviewed outcomes of patients. Cases with unilateral VS who had undergone primary microsurgery via retrosigmoidal approach between 1995 and 2021 were investigated. Complete tumor removal was defined as gross total resection (GTR), a capsular remnant was categorized as near total resection (NTR) and residual tumor was designated as subtotal resection (STR). The primary endpoint was radiological recurrence-free survival. 386 patients fulfilled the inclusion criteria of the study and were evaluated. GTR was achieved in 284 patients (73.6%), NTR was achieved in 63 patients (10.1%) and STR was present in 39 patients (16.3%). A total of 28 patients experienced recurrences with significant differences in the three subgroups. The strongest predictor of recurrence was the extent of resection, with patients who underwent STR having an almost 10-fold higher risk of recurrence and patients who had undergone NTR having an almost 3-fold higher risk than those treated with GTR. More than 20% of recurrences (6/28) occured after more than 5 years. The degree of resection is an important guide to the interval of follow-up, but long-term follow-up should be considered also in the case of GTR. The majority of recurrences occurs after 3-5 years. Nevertheless, a follow-up of at least 10 years should be carried out.

Surgical and Functional Outcome after Resection of 64 Petroclival Meningiomas.

Simple SummaryMeningiomas are common brain tumors, which are generally treated by surgery or radiation. When these tumors are situated in difficult to reach locations within the skull, such as petroclival meningiomas, surgery may elicit impairments of cranial nerve function postoperatively. These may have a substantial impact on the postoperative quality of life of patients. Modern surgical strategies accept incomplete tumor removal in favor of preservation of cranial nerve function. With our study, we investigated the occurrence of these impairments and their recovery over time in a series of surgically treated petroclival meningiomas, applying different surgical approaches and postoperative radiation therapy in some patients. We were able to find favorable recovery rates of most postoperative impairments with a high rate of complete tumor removal. Preoperatively, we identified tumors unsuitable for complete removal due to their infiltration of the cavernous sinus or brain stem affection on magnetic resonance imaging.Objective: The management of petroclival meningiomas (PCMs) remains notoriously difficult due to their close association with neurovascular structures and their complex anatomy, hence the surgical paradigm change from radical to functional resection in the past. With this study, we aimed to analyze surgical and functional outcomes of a modern consecutive series of patients with PCMs. Methods: We reviewed patient charts and imaging data of 64 consecutive patients from 2006 to 2018 with a PCM resected at our institution and compared surgical and functional outcomes between subgroups stratified by surgical approach. Results: Females comprised 67.2% of patients (n = 43), with a mean age of 55 years (median 56; range 21–84). Follow-up data were available for 68.8% and reached a mean of 42.3 months (range 1–129) with a median of 28.5 months. The mean tumor diameter was 37.3 mm (standard deviation (SD) 15.4; median 37.0). Infiltration of the cavernous sinus was observed in 34 cases (53.1%), and the lesions affected the brain stem in 28 cases (43.8%). Preoperative cranial nerve palsy was observed in 73.4% of cases; trigeminal neuropathy (42.2%), hearing loss (32.8%), and impairment of vision (18.8%) were the most common. A retrosigmoid approach was employed in 47 cases (78.1%), pterional in 10 (15.6%), combined petrosal in 2 (3.1%), and transnasal and subtemporal in 1 (1.6%). Fifteen cases (23.4%) were resected in a two-staged fashion. Gross total resection (GTR) was attempted in 30 (46.9%) cases without cavernous sinus infiltration and was achieved in 21 (70.0%) of these cases. Surgical complications occurred in 13 cases (20.3%), most commonly meningitis (n = 4; 6.3%). Postoperatively, 56 patients (87.5%) developed new cranial nerve palsy, of which 36 (63.6%) had improved or resolved on last follow up. Achieving GTR was not significantly associated with higher rates of surgical complications (chi-square; p = 0.288) or postoperative cranial nerve palsy (chi-square; p = 0.842). Of all cases, 20 (31.3%) underwent postoperative radiation. Tumor progression was observed in 10 patients (15.9%) after a mean 102 months (median 124). Conclusions: Surgical resection remains the mainstay of treatment for PCMs, with perioperative cranial neuropathies exhibiting favorable recovery rates. Most essentially, the preselection of patients with hallmarks of brain stem affection and cavernous sinus infiltration should dictate whether to strive for a functionally oriented strategy in favor of radical resection.

Effectiveness and Toxicity of Fractionated Proton Beam Radiotherapy for Cranial Nerve Schwannoma Unsuitable for Stereotactic Radiosurgery.

PurposeIn this benign tumor entity, preservation of cranial nerve function is of special importance. Due to its advantageous physical properties, proton beam radiotherapy (PRT) is a promising approach that spares healthy tissue. Could PRT go along with satisfactory preservation rates for cranial nerve function without compromising tumor control in patients with cranial nerve schwannoma unsuitable for stereotactic radiosurgery?MethodsWe analyzed 45 patients with cranial nerve schwannomas who underwent PRT between 2012 and 2020 at our institution. Response assessment was performed by MRI according to RECIST 1.1, and toxicity was graded following CTCAE 5.0.ResultsThe most common schwannoma origin was the vestibulocochlear nerve with 82.2%, followed by the trigeminal nerve with 8.9% and the glossopharyngeal nerve as well as the vagal nerve, both with each 4.4%. At radiotherapy start, 58% of cranial nerve schwannomas were progressive and 95.6% were symptomatic. Patients were treated with a median total dose of 54 Gy RBE in 1.8 Gy RBE per fraction. MRI during the median follow-up period of 42 months (IQR 26–61) revealed stable disease in 93.3% of the patients and partial regression in 6.7%. There was no case of progressive disease. New or worsening cranial nerve dysfunction was found in 20.0% of all patients, but always graded as CTCAE °I-II. In seven cases (16%), radiation-induced contrast enhancements (RICE) were detected after a median time of 14 months (range 2–26 months). RICE were asymptomatic (71%) or transient symptomatic (CTCAE °II; 29%). No CTCAE °III/IV toxicities were observed. Lesions regressed during the follow-up period in three of the seven cases, and no lesion progressed during the follow-up period.ConclusionThese data demonstrate excellent effectiveness with 100% local control in a median follow-up period of 3.6 years with a promising cranial nerve functional protection rate of 80%. RICE occurred in 16% of the patients after PRT and were not or only mildly symptomatic.

Total Petrosectomy for the Total Resection of Sphenopetroclival Meningioma: 2-Dimensional Operative Video.

Sphenopetroclival meningioma is a most formidable meningioma. Many patients have few preoperative deficits and surgery has the potential of severe neurological complications. Surgical treatment is challenging due to brainstem compression, the involvement of multiple cranial nerves and cerebral vessels. Wide tumor exposure, multiple dissection axis, and short distance are paramount factors in the quest of achieving total removal of Simpson grade I, including the involved dura and bone. The posterior petrosal, transtentorial presigmoid approach offers a wide and shallow operative field.1-7 When the patient has hearing loss, extending the resection of the temporal bone provides unmatchable exposure facilitating safer and more complete tumor removal. This article demonstrates the removal of a sphenopetroclival meningioma through total petrosectomy with closing of the external auditory canal and preservation of the facial nerve in the Fallopian canal. A total resection of the tumor was achieved with long-term preservation of cranial nerve function. The surgical steps of total petrosectomy are shown, including the skin flap, combined middle and posterior fossa craniotomy, skeletonization of the sigmoid transverse sinus, radical mastoidectomy, dissection of the Fallopian canal, and drilling of the labyrinth, cochlea, and petrous apex for superb exposure.8 We demonstrate the intra-arachnoidal microsurgical dissection utilized for the radical resection of petroclival meningioma. This surgery performed in 1995 is a testament to the time-tested technique. The patient consented to the procedure and image use. Images at 1:33 and 3:57 © Ossama Al-Mefty, used with permission.

Trigger electromyography in endoscopic transnasal surgery of skull base tumors

Introduction . The development of minimally invasive technologies in recent decades has expanded the indications for the use of endoscopic transnasal transsphenoidal approaches in surgery of skull base tumors. It became possible to perform surgical interventions aimed at removing tumors of the base of the skull that spread to the area of the passage of cranial nerves (cavernous sinus, clival area, cerebello-pontine angle), which is associated with the risk of damage to certain cranial nerves. The study objective is to evaluate the effectiveness of trigger electromyography in providing anatomical and functional preservation of cranial nerves during endoscopic endonasal transsphenoidal removal of skull base tumors. Materials and methods . The study is based on statistical analysis and comparison of the results of surgical treatment of two groups of patients with various tumors of the base of the skull: the main group (30 patients with using trigger electromyography to identify cranial nerves intraoperatively) and the control group (43 patients without using this method). The effectiveness and safety of using the method of intraoperative identification of cranial nerves was evaluated based on a comparison of basic characteristics, treatment outcomes, and factors potentially affecting them. Results . Fifty-seven (57) cranial nerves were identified intraoperatively in the main group. The frequency of radical removal was 1.6 times higher in the main group (70 % vs 44.2 %, p = 0.03). When analyzing the dynamics of the state of motor cranial nerves after surgery in the main and control groups, it was shown that negative dynamics prevailed in the control group — 37.2 % vs 13.3 % (p = 0.03), and positive dynamics prevailed in the main group (37.3 % vs 13.9 %), 2.8 times (p = 0.08). Conclusion . The obtained data indicate that the use of the intraoperative identification method in endoscopic transnasal surgery of skull base tumors can positively affect the radical removal of tumors and the preservation of cranial nerve function in the postoperative period.

Correlation of Preoperative Cranial Nerve Diffusion Tensor Tractography with Intraoperative Findings in Surgery of Cerebellopontine Angle Tumors

Imaging to visualize nerves around tumors preoperatively could help the surgeon to plan the surgery and excise the tumor with preservation or improvement in patients' quality of life. In the present prospective study, we attempted to correlate the preoperative cranial nerves (i.e., trigeminal, abducens, facial, and vestibulocochlear diffusion tensor tractography and anatomic magnetic resonance imaging [MRI] findings) with intraoperative findings during cerebellopontine angle (CPA) tumor surgery. The 40 enrolled patients had CPA tumors (31 vestibular schwannomas, 5 epidermoid tumors, 2 meningiomas, 2 trigeminal schwannomas). All the patients were undergoing microsurgery for the first time. They underwent preoperative MRI for anatomic and diffusion tensor imaging (DTI) data. The imaging series were postprocessed, and 3-dimensional images were obtained. The location of the involved nerves around the tumors was recorded during surgery by the senior surgeon, who was kept unaware of the results of the fiber tracking, and a correlation was performed. We evaluated the correlation between the DTI and intraoperative findings for the nerve location in relation to the tumor in the CPA. The correlation between the DTI and intraoperative findings for the facial, trigeminal, and vestibulocochlear nerves was 85% (34 of 40), 85% (34 of 40), and 75% (12 of 16), respectively. The modified technical parameters proposed could lead to better preservation of cranial nerve function, especially for patients with large tumors. To the best of our knowledge, the present study is the first systematic study of relevant cranial nerves in 40 patients with demonstration of the vestibulocochlear bundle by preoperative MRI in the most common CPA tumors using advanced MRI sequences such as diffusion tensor tractography and capturing the data in a multiplanar format.

Preservation of cranial nerve function following awake surgery for benign brain tumors in 22 consecutive patients

BackgroundPreservation of cranial nerve function in patients with benign tumors such as meningiomas and vestibular schwannomas remains difficult following microsurgery. MethodsIn this study, awake surgery was performed in 22 consecutive patients with meningiomas or vestibular schwannomas that compressed cranial nerves (I–XII). Improved, unchanged, or deteriorated cranial nerve function after surgery was evaluated. ResultsThe function of 44 cranial nerves in 22 consecutive patients who underwent awake surgery for meningiomas or vestibular schwannomas improved, was unchanged, or deteriorated in eight, 35, and one nerves, respectively. Regarding the function of the olfactory (Ist) nerve, which is difficult to preserve, hyposmia improved after surgery in two patients with olfactory groove meningiomas. Regarding the auditory (VIIIth) nerve, which is also difficult to preserve, the function was improved, unchanged, or deteriorated after surgery in two, 11, and one patients, respectively, with cerebello-pontine angle meningiomas or vestibular schwannomas. In all patients with serviceable auditory function before surgery, function was preserved after surgery. In the same patients, the function of the facial (VIIth) nerve was also preserved after surgery in all patients. ConclusionsThese results suggest that awake surgery for benign brain tumors such as meningiomas and vestibular schwannomas is associated with low patient morbidity regarding cranial nerve function.

Natural History, Multimodal Management, and Quality of Life Outcomes of Trigeminal Schwannomas.

Background Trigeminal schwannomas are the second most common among intracranial schwannomas. These can arise from anywhere between the root and the distal extracranial branches of the trigeminal nerve. Clinical presentation depends on location and size, including but not limited to facial hypesthesia or pain, headaches, dizziness, ataxia, and diplopia. Literature is strikingly scant discussing the natural history of these lesions, while the treatment goals are heavily dependent on tumor presentation. Management decisions must be individualized to each tumor and each patient, while attempting to maximize the quality of life. We present the natural history of these lesions as well as their management by surgical resection or radiation therapy, and report long-term quality of life outcomes. Methods Between 2001 and 2015, 24 patients (66.7% female) with trigeminal schwannomas were diagnosed and managed at Vancouver General Hospital. We analyzed the clinical presentation, surgical results, resection rates, patient quality of life, and complications. To complete the evaluation, we prospectively collected 36-Item Short Form Health Survey (SF-36) quality of life assessments for comparison. Results We identified 12 patients treated with a craniotomy and surgical resection, 4 were treated with radiation therapy, while 8 patients were followed by observation. Mean age of study cohort was 49.2 years (range, 23-79 years), and most patients presented with facial hypesthesia (54.2%) and headaches (37.5%), while 37.5% were incidental findings. There were no major differences in patient demographics between the three groups. Patients offered surgery had larger lesions (mean diameter, 3.4 ± 1.1 cm) when compared with those that were irradiated or observed, and were more likely to have extracranial extension. Overall patient quality of life improved following treatment (ΔSF-36 + 12.9) at 3.9 years. Conclusions The treatment goals of trigeminal schwannomas focus on improvement in neurologic symptoms, relief of mass effect, and preservation of cranial nerve function. We demonstrate that smaller lesions found incidentally with minimal symptoms can be followed safely with serial imaging, with 1 of 9 (11.1%) progressing to require treatment over the course of 7.1 years. Management of trigeminal schwannomas should be individualized with an involvement of a multidisciplinary skull base team.

Determining Brain Death: Basic Approach and Controversial Issues.

Determining Brain Death: Basic Approach and Controversial Issues.

Long-Term Results of CyberKnife Radiosurgery for Vestibular Schwannoma

Objective Since the 2000s, CyberKnife radiosurgery (CKRS) is either a primary or an adjunct management approach used to treat patients with vestibular schwannoma (VS). The goals of CKRS are prevention of tumor growth, preservation of cranial nerve function and prevention of new neurologic deficiencies. The aim of this study was to assess the efficacy and safety of CKRS, in terms of tumor control, hearing preservation, and complications. Methods Forty patients with VS underwent CKRS as a treatment modality for from January 2010 to February 2016. The long term results of 32 patients were evaluated who received CKRS as primary treatment. 8 patients presented with previously performed surgical resection. Information related to clinical history, Brain MRI and outcomes of patients with VS collected retrospectively by reviewing patient’s chart and telephone survey. Results The mean tumor volume was 3.3 cm3 and the mean follow-up was 41 months. The most recent follow-up showed that tumor size decreased in 17 patients (42.5%), displayed no change in 19 patients (47.5%), and increased in 4 patients (10%). Progression-free survival rates after CKRS at 1, 3, and 5 years were 95%, 90%, and 90%. After CKRS, 13 patients experienced hearing degradation. The overall rate of preservation of serviceable hearing at the long-term follow-up was 60%. Vertigo, ataxia, and headache were improved after CKRS compared with pretreated status. But, facial weakness, trigeminal nerve neuropathy, and tinnitus were worsen. Conclusion CKRS provide an excellent tumor control rate and a comparable hearing preservation rate in VS patients. Also CKRS is associated with low rate of cranial neuropathy, other complications. Keywords: Vestibular schwannoma; Radiosurgeries; Follow-up studies 중심 단어: ì „ì •ì‹ ê²½ì´ˆì¢ , ë°©ì‚¬ì„ ìˆ˜ìˆ , ì¶”ì  연구

Multimodality Management of Trigeminal Schwannomas.

Patients presenting with trigeminal schwannomas require multimodality management by a skull base surgical team that can offer expertise in both transcranial and transnasal approaches as well as radiosurgical and microsurgical strategies. Improvement in neurologic symptoms, preservation of cranial nerve function, and control of mass effect are the primary goals of management for trigeminal schwannomas. Complete surgical resection is the treatment of choice but may not be possible in all cases. Radiosurgery is an option as primary management for small- to moderate-sized tumors and can be used for postoperative residuals or recurrences. Planned surgical resection followed by SRS for residual tumor is an effective option for larger trigeminal schwannomas. The endoscopic resection is an excellent approach for patients with an extradural tumor or tumors isolated to the Meckel cave. A detailed analysis of a tumor and its surroundings based on high-quality imaging can help better estimate the expected outcome from each treatment. An expert skull base team should be able to provide precise counseling for each patient's situation for selecting the best option.

Treatment of giant acoustic neuromas

To analyze the treatment modality and outcome of a series of patients with giant acoustic neuromas, a particular type of tumour characterised by their size (extracanalicular diameter of 4cm or more) and high morbidity and mortality. This was a retrospective unicentre study of patients with acoustic neuromas treated in a period of 12 years. In our institutional series of 108 acoustic neuromas operated on during that period, we found 13 (12%) cases of giant acoustic neuromas. We reviewed the available data of these cases, including presentation and several clinical, anatomical, and microsurgical aspects. All patients were operated on by the same neurosurgeon and senior author (EU) using the suboccipital retrosigmoid approach and complete microsurgical removal was achieved in 10 cases. In one case, near total removal was deliberately performed, in another case a CSF shunt was placed as the sole treatment measure, and in the remaining case no direct treatment was given. One patient died in the immediate postoperative period. One year after surgery, 4 patients showed facial nerve function of iii or more in the House-Brackman scale. The 4 most important prognostic characteristics of giant acoustic neuromas are size, adhesion to surrounding structures, consistency and vascularity. Only the first of these is evident in neuroimaging. Giant acoustic neuromas are characterised by high morbidity at presentation as well as after treatment. Nevertheless, the objective of complete microsurgical removal with preservation of cranial nerve function is attainable in some cases through the suboccipital retrosigmoid approach.

Middle Fossa Approach for Total Resection of Petrous Apex Cholesterol Granulomas

Cholesterol granulomas (CGs) of the petrous apex (PA) are rare, benign, expanding lesions. Surgical treatment is recommended for patients with symptomatic disease; however, the optimal surgical procedure is still controversial due to high recurrence rates. The main treatment strategy is divided into drainage and complete resection. We advocate radical resection of the lesion by the middle fossa approach and reconstruction with a vascularized galeofascial flap. A 10-year retrospective case review of 17 patients undergoing surgical treatment of PA CGs between 2000 and 2010 was undertaken. Operative outcomes and surgical complications were analyzed. In addition, our operative method and the related anatomy are described from cadaveric dissections. All but 1 patient was operated on via a middle fossa approach. Using the middle fossa approach, radical resection of all PA CGs was achieved with obliteration of the cyst cavity using a vascularized flap. Important surrounding structures included the internal auditory canal, cochlea, petrous carotid artery, and abducens nerve. There was 1 death caused by internal carotid artery occlusion. No other major complications or cranial nerve deficits occurred postoperatively. Clinical recurrence occurred in 1 patient (5.9%). Our technique of radical resection and reconstruction with a vascularized flap has the advantage of being less invasive with less cosmetic deformity and allows preservation of cranial nerve function with a low recurrence rate. Knowledge of the surgical anatomy and the characteristics of CG is prudent because important neurovascular structures may be exposed behind the CG wall due to bony erosion.

Pituitary adenomas: Surgery and radiotherapy in the age of molecular diagnostics and pathology

appear in the general population in 1 out of 1000 people, approximately 300,000 people in the United States have (or have had) such a tumor at present, and they are relatively common in oncology practice. The clinical syndromes caused by pituitary tumors depend on their size, hormonal status, and degree of invasiveness. These tumors arise from the adenohypophysis (anterior lobe) of the pituitary gland within the sella turcica. In this location, the primary mass effect caused by a small tumor is exerted against the adjacent normal gland, which is slowly compressed and shifted as the adenoma increases in size. If the tumor grows large enough to escape the confines of the sella by superior extension, the result is elevation, compression, and ultimately dysfunction of the optic nerves or chiasm or both, with resulting loss of vision. Although the majority of pituitary tumors show microscopic evidence of dural invasion, clinically significant invasion into 1 or both of the cavernous sinuses placed lateral to the sella occurs in o20%. 2,3 When cavernous sinus invasion is profound to the point of expanding its dural enclosure, the potential for cranial neuropathy exists. Luckily, most pituitary tumors invading the cavernous sinus do not affect its contents and permit excellent preservation of flow through the internal carotid artery and preservation of cranial nerve function. Tumors compressing the pituitary gland would typically cause a loss of anterior hormone function (ie, in one or more of the hormones produced by the anterior lobe: growth hormone (GH), prolactin (PRL), luteinizing hormone (LH), follicle-stimulating hormone (FSH), adrenocorticotropin (ACTH), and thyrotropin (TSH)). Conversely, if the tumor is itself functional and produces and secretes hormones independently of the normal gland, 1 or more of these same hormones may be present in excess. Thus, pituitary tumors can produce hormonal hypersecretion, hyposecretion, or a combination of the 2 with clinical sequelae dependent on the combination of hormonal alterations seen and the severity of derangement. In treating pituitary tumors, physicians must control (and ideally, reduce) mass effect and work to maintain or normalize pituitary hormone levels. The goals of treatment in pituitary adenomas are outlined in Table 1.

Hearing Preservation after Stereotactic Radiosurgery for Bilateral Cerebellopontine Angle Meningiomas

Preservation of cranial nerve function is critical in the management of patients with cerebellopontine angle (CPA) tumors. A 51-year-old woman with tinnitus and dizziness was discovered to have bilateral CPA dural-based masses extending into the internal auditory canals (IAC). Pre-operatively, the patient had normal hearing on the right (SRT, 5 dB; SDS 100% at 30 dB) and left (SRT, 10 dB; SDS 90% at 40 dB). The patient underwent two Leksell Gamma Knife (Elekta Instruments, Norcross, GA) radiosurgeries initially for the larger left-sided tumor, then one year later for the right. The margin dose for each tumor was 14 Gy. Six years after the first radiosurgery, the tumors have not progressed and she has retained normal hearing and facial function bilaterally. Preservation of cranial nerve function is generally possible after stereotactic radiosurgery of CPA meningiomas.

Microsurgical results with large vestibular schwannomas with preservation of facial and cochlear nerve function as the primary aim

To evaluate our microsurgical results in dealing with vestibular schwannomas (VS) greater than or equal to 30 mm when preservation of cranial nerve function was considered more important than total tumour removal. Sixteen consecutive cases were operated on by the same neurosurgeon according to a prospective protocol using intraoperative neuro-monitoring (IONM) based on electromyographic and brain stem auditory evoked potential recordings. Facial nerve function was evaluated on the House-Brackmann Scale and cochlear nerve function on the Gardner-Robertson Scale. Someone not involved in the clinical management of our patients collected all data. Fifteen patients showed facial nerve (FN) function of House-Brackmann grade (HBG) I or II at one year postoperatively and one kept the HBG IV she had preoperatively. Two patients of four maintained a cochlear nerve function of Gardner-Robertson grade (GRG) II. The tumour excision rates were: total, 68.7%; near total, 6.3%; subtotal, 18.7%, and partial, 6.3%. The average follow-up was 55 months (1-106). Three patients underwent radiotherapy later with growth stabilisation and no additional morbidity. When dealing with VS greater than or equal to 30 mm, microsurgery guided by IONM, with a rate of total or near-total tumour excision of about 75%, can retain socially acceptable facial nerve function (HBG I or II) in all cases and serviceable hearing (GRG I or II) in two cases out of four. Maintaining serviceable cranial nerve function should take precedence over total tumour excision.

Radiosurgery of vestibular schwannomas: summary of experience in 829 cases

Object. Management options for vestibular schwannomas (VSs) have greatly expanded since the introduction of stereotactic radiosurgery. Optimal outcomes reflect long-term tumor control, preservation of cranial nerve function, and retention of quality of life. The authors review their 15-year experience. Methods. Between 1987 and 2002, some 829 patients with VSs underwent gamma knife surgery (GKS). Dose selection, imaging, and dose planning techniques evolved between 1987 and 1992 but thereafter remained stable for 10 years. The average tumor volume was 2.5 cm3. The median margin dose to the tumor was 13 Gy (range 10–20 Gy). No patient sustained significant perioperative morbidity. The average duration of hospital stay was less than 1 day. Unchanged hearing preservation was possible in 50 to 77% of patients (up to 90% in those with intracanalicular tumors). Facial neuropathy risks were reduced to less than 1%. Trigeminal symptoms were detected in less than 3% of patients whose tumors reached the level of the trigeminal nerve. Tumor control rates at 10 years were 97% (no additional treatment needed). Conclusions. Superior imaging, multiple isocenter volumetric conformal dose planning, and optimal precision and dose delivery contributed to the long-term success of GKS, including in those patients in whom initial microsurgery had failed. Gamma knife surgery provides a low risk, minimally invasive treatment option for patients with newly diagnosed or residual VS. Cranial nerve preservation and quality of life maintenance are possible in long-term follow up.

Radiosurgery of vestibular schwannomas: summary of experience in 829 cases

Management options for vestibular schwannomas (VSs) have greatly expanded since the introduction of stereotactic radiosurgery. Optimal outcomes reflect long-term tumor control, preservation of cranial nerve function, and retention of quality of life. The authors review their 15-year experience. Between 1987 and 2002, some 829 patients with VSs underwent gamma knife surgery (GKS). Dose selection, imaging, and dose planning techniques evolved between 1987 and 1992 but thereafter remained stable for 10 years. The average tumor volume was 2.5 cm3. The median margin dose to the tumor was 13 Gy (range 10-20 Gy). No patient sustained significant perioperative morbidity. The average duration of hospital stay was less than 1 day. Unchanged hearing preservation was possible in 50 to 77% of patients (up to 90% in those with intracanalicular tumors). Facial neuropathy risks were reduced to less than 1%. Trigeminal symptoms were detected in less than 3% of patients whose tumors reached the level of the trigeminal nerve. Tumor control rates at 10 years were 97% (no additional treatment needed). Superior imaging, multiple isocenter volumetric conformal dose planning, and optimal precision and dose delivery contributed to the long-term success of GKS, including in those patients in whom initial microsurgery had failed. Gamma knife surgery provides a low risk, minimally invasive treatment option for patients with newly diagnosed or residual VS. Cranial nerve preservation and quality of life maintenance are possible in long-term follow up.

Surgery of cerebellopontine angle epidermoid cysts: Role of the widened retrolabyrinthine approach combined with endoscopy

Objectives To evaluate the use of the retrolabyrinthine approach (RLA) combined with endoscopy with particular reference to preservation of cranial nerve function and completeness of excision in surgery of epidermoid cysts. Methods A retrospective study was performed on a series of 8 consecutive patients of whom 7 have undergone surgery. Main outcome measures Measures include audiological and neurological status preoperatively and postoperatively, size of the lesion, the surgical approach, completeness of excision, and operative morbidity. Results The tumors were all large, ranging from 2 × 3 cm to 6 × 6 cm. Presenting symptoms were headache (75%), dysequilibrium (62%), trigeminal nerve palsy (38%), abducens nerve palsy (25%), and, rarely, auditory symptoms. Seven patients underwent surgery, 5 by the RLA, 1 by a translabyrinthine approach (TLA), and 1 by a transcochlear approach. Complete excision was achieved in 5 of the 7 patients. A transtentorial approach was combined in 2 cases (1 RLA, 1 TLA). Endoscopy was used in 3 cases. It allowed a complete tumor excision. One case of keratinous meningitis was observed. Trigeminal nerve function returned to normal in all patients. Postoperative facial nerve function was grade I in 5 cases and grade III in 2 cases. Hearing was preserved in 3 cases as class A, 1 case as class B. In the 2 cases presenting with abducens nerve palsy preoperative symptoms were initially aggravated before returning to normal function by 1 year postoperatively. The RLA with endoscopy allowed less invasive surgery and preservation of hearing in 4 of the 5 cases where it was attempted. Tumor control appeared better than with the suboccipital approach. Mortality and postoperative morbidity also appear reduced. Conclusion RLA combined with endoscopy should be considered as the standard approach for excision of epidermoid cysts. Extension of this approach into a TLA or transcochlear approach will depend on preoperative difficulties and preoperative hearing.