Repair of Frontoethmoidal Encephalocele in the Philippines: An Account of 30 Cases Between 2008-2013.

BACKGROUND: Frontoethmoidal encephalocele is a congenital abnormality of the anterior skull base involving herniation of cranial contents through a midline skull defect. Patency of the foramen cecum, along with other multifactorial variables, contributes to the development of frontoethmoidal encephaloceles. Because of limited resources, financial constraints, and lack of surgical expertise, repair of frontoethmoidal encephaloceles is limited in developing countries. METHODS: Between 2008 and 2013 an interdisciplinary team composed of neurosurgeons, craniofacial surgeons, otolaryngologists, plastic surgeons, and nursing personnel, conducted surgical mission trips to Davao City in Mindanao, Philippines. All patients underwent a combined extracranial/intracranial surgical approach, performed in tandem by a neurosurgeon and a craniofacial surgeon, to detach and remove the encephalocele. This procedure was followed by reconstruction of the craniofacial defects. RESULTS: A total of 30 cases of frontoethmoidal encephalocele were repaired between 2008 and 2013 (20 male; 10 female). The average age at operation was 8.7 years, with 7 patients older than 17 years. Of the 3 subtypes, the following breakdown was observed in patients: 18 nasoethmoidal; 9 nasofrontal; and 3 naso-orbital. Several patients showed concurrent including enlarged ventricles, arachnoid cysts (both unilateral and bilateral), and gliotic changes, as well as orbit and bulbus oculi (globe) deformities. There were no operative-associated mortalities or neurologic deficits, infections, or hydrocephalus on follow-up during subsequent trips. CONCLUSIONS: Despite the limitations of performing advanced surgery in a developing country, the combined interdisciplinary surgical approach has offered effective treatment to improve physical appearance and psychological well-being in afflicted patients.

Stereotactic radiosurgery for cerebral arteriovenous malformations: evaluation of long-term outcomes in a multicenter cohort.

OBJECTIVE In this multicenter study, the authors reviewed the results following Gamma Knife radiosurgery (GKRS) of cerebral arteriovenous malformations (AVMs), determined predictors of outcome, and assessed predictive value of commonly used grading scales based upon this large cohort with long-term follow-up. METHODS Data from a cohort of 2236 patients undergoing GKRS for cerebral AVMs were compiled from the International Gamma Knife Research Foundation. Favorable outcome was defined as AVM obliteration and no posttreatment hemorrhage or permanent symptomatic radiation-induced complications. Patient and AVM characteristics were assessed to determine predictors of outcome, and commonly used grading scales were assessed. RESULTS The mean maximum AVM diameter was 2.3 cm, with a mean volume of 4.3 cm3. A mean margin dose of 20.5 Gy was delivered. Mean follow-up was 7 years (range 1-20 years). Overall obliteration was 64.7%. Post-GRKS hemorrhage occurred in 165 patients (annual risk 1.1%). Radiation-induced imaging changes occurred in 29.2%; 9.7% were symptomatic, and 2.7% had permanent deficits. Favorable outcome was achieved in 60.3% of patients. Patients with prior nidal embolization (OR 2.1, p < 0.001), prior AVM hemorrhage (OR 1.3, p = 0.007), eloquent location (OR 1.3, p = 0.029), higher volume (OR 1.01, p < 0.001), lower margin dose (OR 0.9, p < 0.001), and more isocenters (OR 1.1, p = 0.011) were more likely to have unfavorable outcomes in multivariate analysis. The Spetzler-Martin grade and radiosurgery-based AVM score predicted outcome, but the Virginia Radiosurgery AVM Scale provided the best assessment. CONCLUSIONS GKRS for cerebral AVMs achieves obliteration and avoids permanent complications in the majority of patients. Patient, AVM, and treatment parameters can be used to predict long-term outcomes following radiosurgery.

Fully Endoscopic Retrosigmoid Vestibular Nerve Section for Refractory Meniere Disease.

OBJECTIVE: This study aims to report our results and technical details of fully endoscopic retrosigmoid vestibular nerve section. DESIGN: A prospective observational study was conducted. SETTING: A single academic, tertiary institution involving neurosurgery and neurotology. PARTICIPANTS: Previously diagnosed patients with Meniere disease, refractory to medical therapy, who underwent fully endoscopic vestibular nerve section. MAIN OUTCOME MEASURES: Postoperative improvement in vertiginous symptoms as well as hearing preservation, based on the American Association of Otolaryngology-Head and Neck Surgeons score and the Gardener and Robertson-Modified Hearing Classification. Facial nerve preservation based on the House-Brackman (HB) score. RESULTS: Symptoms improved or resolved in 38 of 41 (92.2%) patients with only 1 of 41 (2.4%) reporting worsening symptoms. All 41 patients (100%) had a postoperative HB score of 1/6, demonstrating full facial nerve preservation. Hearing was stable or improved in 34 of 41 (82.9%) patients. Three complications took place for a rate of 7.3%, one cerebrospinal fluid leak, and two wound infections. CONCLUSION: The fully endoscopic approach to vestibular nerve sections is a safe and effective technique for the treatment of medically refractory Meniere disease. This technique also utilizes smaller incisions, minimal cranial openings, and no cerebellar retraction with improved visualization of the cerebellopontine angle neurovascular structures.

Surgical Resection of Brain Metastases and the Risk of Leptomeningeal Recurrence in Patients Treated With Stereotactic Radiosurgery.

PURPOSE: Recent prospective data have shown that patients with solitary or oligometastatic disease to the brain may be treated with upfront stereotactic radiosurgery (SRS) with deferral of whole-brain radiation therapy (WBRT). This has been extrapolated to the treatment of patients with resected lesions. The aim of this study was to assess the risk of leptomeningeal disease (LMD) in patients treated with SRS to the postsurgical resection cavity for brain metastases compared with patients treated with SRS to intact metastases. METHODS AND MATERIALS: Four hundred sixty-five patients treated with SRS without upfront WBRT at a single institution were identified; 330 of these with at least 3 months' follow-up were included in this analysis. One hundred twelve patients had undergone surgical resection of at least 1 lesion before SRS compared with 218 treated for intact metastases. Time to LMD and overall survival (OS) time were estimated from date of radiosurgery, and LMD was analyzed by the use of cumulative incidence method with death as a competing risk. Univariate and multivariate analyses were performed with competing risk regression to determine whether various clinical factors predicted for LMD. RESULTS: With a median follow-up time of 9.0 months, 39 patients (12%) experienced LMD at a median of 6.0 months after SRS. At 1 year, the cumulative incidence of LMD, with death as a competing risk, was 5.2% for the patients without surgical resection versus 16.9% for those treated with surgery (Gray test, P<.01). On multivariate analysis, prior surgical resection (P<.01) and breast cancer primary (P=.03) were significant predictors of LMD development. The median OS times for patients undergoing surgery compared with SRS alone were 12.9 and 10.6 months, respectively (log-rank P=.06). CONCLUSIONS: In patients undergoing SRS with deferral of upfront WBRT for intracranial metastatic disease, prior surgical resection and breast cancer primary are associated with an increased risk for the development of LMD.

Fully Endoscopic Resection of Cerebellopontine Angle Meningiomas.

OBJECTIVE: To describe our operative technique and results from patients who underwent fully endoscopic resection of cerebellopontine angle (CPA) meningiomas. DESIGN: Prospective observational study. SETTING: A single academic institution that includes both neurosurgery and neuro-otology. PARTICIPANTS: Eleven consecutive patients who underwent fully endoscopic resection of a CPA meningioma. MAIN OUTCOME MEASURES: Hearing preservation, based on the American Association of Otolaryngology-Head and Neck Surgeons score as well as facial nerve preservation base on the House-Brackmann (HB) score. In addition, the extent of resection and complication rates was studied. RESULTS: All 11 patients underwent successful gross total resection, Simpson grade 2, of their meningioma, seen both intraoperatively and on postoperative imaging. Overall, 100% of patients maintained normal facial nerve function (HB 1/6). Audiometric testing revealed that 10 of 11 patients maintained either stable or improved hearing postoperatively based on Committee on Hearing and Equilibrium Guidelines for the Evaluation of Hearing Preservation in Acoustic Neuroma grade with the remaining patient retaining serviceable hearing. Tumor size ranged from 0.5 to 2.5 cm (mean: 1.54 cm). Mean operative time was 166 minutes (range: 122-207 minutes); estimated blood loss averaged 54.5 mL. Hospital length of stay ranged from 2 to 6 days (mean: 3.1 days), and a superficial wound infection was the only complication seen in one patient. CONCLUSION: Fully endoscopic techniques can be used in CPA meningioma resection with excellent clinical results as an alternative to the traditional open microscopic approach.

Synovial chondromatosis presenting as an epidural mass.

BACKGROUND: Synovial chondromatosis is an uncommon disorder characterized by the formation of multiple cartilaginous nodules in the synovium of the facet joint. It most commonly affects large joints such as hip or shoulder. Commonly seen features are bony erosion and calcifications. Synovial chondromatosis is rare in the spine and there are few previous reports of extension into the spinal canal. CASE DESCRIPTION: A 58-year-old man presented with a 2 year history of progressive numbness in the right upper extremity without objective weakness. A several month course of conservative management, including physical therapy, failed to alleviate symptoms. Magnetic resonance imaging of the cervical spine demonstrated the erosion of the right facet C5-C6 joint with listhesis and foraminal enlargement secondary to a lesion. Treatment was offered to the patient in the form of surgical resection. The lesion was removed in piecemeal fashion using curettes and Cavitron ultrasonic surgical aspirator. Histological examination demonstrated atypical well-differentiated cartilaginous proliferation. CONCLUSION: This patient had an uncomplicated postoperative course and experienced complete resolution of right upper extremity sensory symptoms. Synovial chondromatosis may compromise cervical spinal cord and nerve roots if it extends into the spinal canal. Although it remains rare, it should be included in the differential diagnosis for upper extremity radiculopathy and myelopathy. Surgical resection is a viable treatment option for symptomatic patients with this pathology. In some cases, adequate resection may necessitate stabilization with instrumentation.

Endoscopic Resection of Vestibular Schwannomas.

Objective To report our results and the technical details of fully endoscopic resection of vestibular schwannomas. Design Prospective observational study. Setting A single academic institution involving neurosurgery and neurotology. Participants Twelve consecutive patients who underwent fully endoscopic resection of a vestibular schwannoma. Main Outcome Measures Hearing preservation, based on the American Association of Otolaryngology-Head and Neck Surgeons (AAO-HNS) score as well as the Gardener and Robertson Modified Hearing Classification (GR). Facial nerve preservation based on the House-Brackmann (HB) score. Results All patients successfully underwent gross total resection. Facial nerve preservation rate was 92% with 11 of 12 patients retaining an HB score of 1/6 postoperatively. Hearing preservation rate was 67% with 8 of 12 patients maintaining a stable AAO-HNS grade and GR score at follow-up. Mean tumor size was 1.5 cm (range: 1-2 cm). No patients experienced postoperative cerebrospinal fluid leak, infection, or cranial nerve palsy for a complication rate of 0%. Mean operative time was 261.6 minutes with an estimated blood loss of 56.3 mL and average length of hospital stay of 3.6 days. Conclusion A purely endoscopic approach is a safe and effective option for hearing preservation surgery for vestibular schwannomas in appropriately selected patients.

Trigeminal neuralgia pain relief after gamma knife stereotactic radiosurgery.

OBJECTIVES: To report outcomes of patients with medical and/or surgical refractory trigeminal neuralgia (TN) treated with gamma knife stereotactic radiosurgery (GK SRS). METHODS: One hundred and forty-nine patients with 152 cases of TN treated with GK SRS were analyzed. All patients, except one, received a dose of 40Gy to the 50% isodose volume. The Barrow Neurological Institute (BNI) pain intensity score was used to grade pain. Actuarial rates of pain relief were calculated. Multiple factors were analyzed for association with pain relief. RESULTS: The median follow up was 27 months (4-71 months). Overall 92% of cases achieved a BNI score I-III after GK SRS. Of those who had pain relief after GK SRS, 32% developed pain recurrence defined as a BNI score of IV or V. The actuarial rate of freedom from pain recurrence (BNI scores I-III) of all treated cases at 1, 2 and 3-years was 76%, 69% and 60%, respectively. On univariate analysis age ≥70 was predictive of better pain relief (p=0.046). Type of pain, prior surgery, multiple sclerosis, number of isocenters, treated nerve length, volume and thickness and distance from the root entry zone to the isocenter were not significant for maintaining a BNI score of I-III. Those who achieved a BNI score of I or II were more likely to maintain pain relief compared to those who only achieved a BNI score of III (93% vs 38% at three years, p<0.01). The rate of pain relief of twenty-seven patients who underwent repeat GK SRS was 70% and 62% at 1 and 2 years, respectively. Toxicity after first GK SRS was minimal with 25% of cases experiencing only new or worsening post-treatment numbness. CONCLUSION: GK SRS provides acceptable pain relief with limited morbidity in patients with medical and/or surgical refractory TN.

Endoscopic vascular decompression for the treatment of trigeminal neuralgia: clinical outcomes and technical note.

OBJECTIVE: This study sought to describe the operative technique and clinical outcomes in a series of 57 patients with trigeminal neuralgia treated with endoscopic vascular decompression (EVD) alone without the use of microscopy at any point. METHODS: A prospective observational study was performed on 57 consecutive patients treated with EVD alone for trigeminal neuralgia from October 2005 to October 2010. Patient outcomes were evaluated with respect to pain abatement, complication rate, length of hospital stay, and overall operative time. Pain outcome was graded using the Barrow Neurological Institute pain intensity score (BNI), with BNI 1 considered an excellent result and BNI 2 or 3 considered a good result. Follow-up ranged from 12 to 72 months, with a mean of 32 months. In addition to reporting these cases, our operative technique for EVD is described in detail. RESULTS: All 57 patients reported severe preoperative pain (BNI 5); 100% of patients achieved immediate postoperative pain control or complete pain relief (BNI 1 to 3), with 82% obtaining an excellent result of BNI 1, and 18% of patients reported good results of BNI 2 or 3. At follow-up, 56 of 57 patients (98%) reported complete relief or well controlled pain (BNI 1 to 3), with 75% obtaining an excellent result of BNI 1; 23% of patients obtained a good result of BNI 2 or 3. The complication rate was 4%, with no mortality. Mean length of hospital stay was 1.6 days, with a range of 1 to 5 days; mean operative time was 133 minutes. CONCLUSIONS: EVD is a safe and highly effective alternative to the more traditional open microvascular decompression or the more recently developed endoscopically assisted microvascular decompression.

Endoscopic assisted resection of prepontine epidermoid cysts.

OBJECTIVE/BACKGROUND: To describe an innovative endoscopic technique to treat prepontine epidermoid cysts. These cysts are typically resected in a microsurgical fashion and can be associated with significant risks and complications. This report is the first description of an endoscopic-assisted removal of an epidermoid cyst without the use of the operative microscope and evaluates the operative findings, technique, and postoperative course. STUDY DESIGN: Retrospective review at tertiary referral center. METHODS: Two patients, one with rapidly progressive headache and ataxia, and another with trigeminal neuralgia were found to have mixed-intensity cystic lesions of the prepontine region consistent with an epidermoid cyst. A detailed description of the preoperative preparation, surgical approach, intraoperative technique, pre- and post-operative imaging findings and monitoring outcomes are emphasized. RESULTS: Both patients underwent resection of the epidermoid cyst using an endoscope-assisted technique. The procedures were 3 and 4 hours in duration with an estimated blood loss of 50 cc in both operations. No intraoperative complications occurred. The patients were discharged from the hospital on postoperative days 2 and 3, respectively. Postoperative imaging revealed no edema of the cerebellum and complete resolution of the cyst. Neurological examination revealed improvement of preoperative symptoms with complete resolution of headache and ataxia of case 1, with resolution of trigeminal neuralgia in case 2. Case 2 did develop an ipsilateral cranial nerve (CN) VI paresis postoperatively that resolved over a 3-week period. The patient from case 1 remains symptom free after 24-months with magnetic resonance imaging (MRI) consistent with gross-total resection of the epidermoid cyst. Case 2 has continued resolution of trigeminal neuralgia and CN VI palsy with 12-month follow-up MRI consistent with gross total resection. CONCLUSIONS: The use of the endoscope as the sole means to access the posterior fossa to treat prepontine cystic lesions affords the surgeon excellent visualization with minimal cerebellar retraction and can be done in a safe and effective manner with little to no morbidity.

Tumor volume as a predictor of survival and local control in patients with brain metastases treated with Gamma Knife surgery.

OBJECT: The aim of this study was to examine tumor volume as a prognostic factor for patients with brain metastases treated with Gamma Knife surgery (GKS). METHODS: Two hundred fifty patients with 1-14 brain metastases who had initially undergone GKS alone at a single institution were retrospectively reviewed. Patients who received upfront whole brain radiation therapy were excluded. Survival times were estimated using the Kaplan-Meier method. Univariate and multivariate analyses using Cox proportional hazard regression models were used to determine if various prognostic factors could predict overall survival, distant brain failure, and local control. RESULTS: Median overall survival was 7.1 months and the 1-year local control rate was 91.5%. Median time to distant brain failure was 8.0 months. On univariate analysis an increasing total tumor volume was significantly associated with worse survival (p = 0.031) whereas the number of brain metastases, analyzed as a continuous variable, was not (p = 0.082). After adjusting for age, Karnofsky Performance Scale score, and extracranial disease on multivariate analysis, total tumor volume was found to be a better predictor of overall survival (p = 0.046) than number of brain metastases analyzed as a continuous variable (p = 0.098). A total tumor volume cutoff value of ≥ 2 cm(3) (p = 0.008) was a stronger predictor of overall survival than the number of brain metastases (p = 0.098). Larger tumor volume and extracranial disease, but not the number of brain metastases, were predictive of distant brain failure on multivariate analysis. Local tumor control at 1 year was 97% for lesions < 2 cm(3) compared with 75% for lesions ≥ 2 cm(3) (p < 0.001). CONCLUSIONS: After adjusting for other factors, a total brain metastasis volume was a strong and independent predictor for overall survival, distant brain failure, and local control, even when considering the number of metastases.

Third ventricle, cerebral aqueduct, and fourth ventricle mixed ependymal neurocytoma: a case report and review of the literature.

PURPOSE: A case report of an 8-year-old female who underwent interhemispheric transcallosal approach to the third ventricle, cerebral aqueduct, and fourth ventricle for resection of a mixed ependymal neurocytoma and review of the literature was evaluated. METHODS: An Ovid MEDLINE review of the literature was conducted starting in 1946 to current using search terms as described in our keywords. RESULTS: A total of 16 neurocytoma have been described in the literature as either posterior third ventricle or posterior fossa in origin. Of these lesions, five have been described as mixed glial-neuronal and all of these were located in the fourth ventricle. To our knowledge, this is the first described mixed glial-neuronal tumor located in the posterior third ventricle and aqueduct.

Improved facial nerve outcomes using an evolving treatment method for large acoustic neuromas.

OBJECTIVE: To describe a successful paradigm for the treatment of large acoustic neuromas (vestibular schwannomas). STUDY DESIGN: Retrospective case review. SETTING: Tertiary referral center. PATIENTS: The charts of 2,875 acoustic neuroma patients at Michigan Ear Institute were reviewed to identify 153 patients who underwent surgical resection for large acoustic neuromas (>=3 cm) between 2000 and 2009. INTERVENTION(S): Staged surgical resection or single stage surgery with or without adjuvant stereotactic radiosurgery. MAIN OUTCOME MEASURE(S): Postoperative facial nerve outcomes are reported using the House-Brackmann (HB) facial nerve grading scale and compared with historical controls from a literature review. Rates of adverse outcomes are also reported. RESULTS: Seventy-five patients underwent staged surgical resection of their tumors, whereas 78 patients underwent either single stage surgery or surgery with subsequent stereotactic radiosurgery. Eighty-one percent of patients in the staged surgical resection group had a postoperative HB Grade I or II facial nerve function compared with 75% in the single stage surgical group. Overall, 78% of patients in the current study had HB Grade I or II after treatment compared with a mean of 53% in the literature for similar sized tumors. Our methods including the decision to use staged surgery when necessary, dissection of tumor with stimulating dissector-directed intraoperative monitoring, and use of adjuvant stereotactic radiosurgery are described. CONCLUSION: Using the described paradigm, large acoustic neuromas can be successfully treated with either staged or single-stage surgical resection with or without adjuvant radiosurgery to obtain more favorable facial nerve outcomes than historically reported controls while minimizing morbidity for the patient.

Hearing preservation in patients with vestibular schwannoma treated with Gamma Knife surgery.

OBJECT: Hearing loss after Gamma Knife surgery (GKS) in patients with vestibular schwannoma has been associated with radiation dose to the cochlea. The purpose of this study was to evaluate serviceable hearing preservation in patients with VS who were treated with GKS and to determine if serviceable hearing loss can be correlated with the dose to the cochlea. METHODS: Forty patients with vestibular schwannoma with serviceable hearing were treated using GKS with a median marginal dose of 12.5 Gy (range 12.5-13 Gy) to the 50% isodose volume. Audiometry was performed prospectively before and after GKS at 1, 3, and 6 months, and then every 6 months thereafter. Hearing preservation was based on pure tone average (PTA) and speech discrimination (SD). Serviceable hearing was defined as PTA less than 50 dB and SD greater than 50%. RESULTS: The median cochlear maximum and mean doses were 6.9 Gy (range 1.6-16 Gy) and 2.7 Gy (range 0.7-5.0 Gy), respectively. With a median audiological follow-up of 35 months (range 6-58 months), the 1-, 2-, and 3-year actuarial rates of maintaining serviceable hearing were 93%, 77%, and 74%, respectively. No patient who received a mean cochlear dose less than 2 Gy experienced serviceable hearing loss (p = 0.035). Patients who received a mean cochlear dose less than 3 Gy had a 2-year hearing preservation rate of 91% compared with 59% in those who received a mean cochlear dose of 3 Gy or greater (p = 0.029). Those who had more than 25% of their cochlea receiving 3 Gy or greater had a higher rate of hearing loss (p = 0.030). There was no statistically significant correlation between serviceable hearing loss and age, tumor size, pre-GKS PTA, pre-GKS SD, pre-GKS Gardner-Robertson class, maximum cochlear dose, or the percentage of cochlear volume receiving 5 Gy. On multivariate analysis there was a trend toward significance for serviceable hearing loss with a mean cochlear dose of 3 Gy or greater (p = 0.074). Local control was 100% at 24 months. No patient developed facial or trigeminal nerve dysfunction. CONCLUSIONS: With a median mean cochlear dose of 2.7 Gy, the majority of patients with serviceable hearing retained serviceable hearing 3 years after GKS. A mean cochlear dose less than 3 Gy was associated with higher serviceable hearing preservation.

The endoscopic approach to vestibular schwannomas and posterolateral skull base pathology.

This article provides an overview of the technical considerations of endoscopy of the posterolateral skull base and cerebellopontine angle (CPA). Specific areas of focus are on the instrumentation requirements for neuroendoscopy of the CPA; the learning curve associated with this technique; and a complete description of the surgical techniques necessary to perform the procedure, along with outcomes and results. The article provides a general overview of the endoscopic approach to the CPA. For a variety of pathologies, the emphasis is on performing this technique for acoustic tumors and hearing preservation. Insights as to how the author's practice evolved in its use of neuroendoscopic procedures are provided.

Craniofacial/Neurosurgery: a multidisciplinary approach to the repair of meningoencephaloceles in a third world country.

The repair of meningoencephaloceles in a third world country does not have to be an unrealized goal. Utilizing a team of specialized experienced physicians to provide the treatment, patient selection, comprehensive planning for all surgical variability, and cooperative management of the patients postoperatively with the hosting physicians is essential to the success of these surgeries. In 2007, a team of physicians, including a neurosurgeon, a craniofacial surgeon, a neurosurgical resident, and nursing personnel, traveled for the first time to Davao, in the Philippines, to repair and reconstruct four patients with meningoencephalocele. The planning, surgical approach, and outcome of the repair of this defect are discussed in this article.

Malignant peripheral nerve sheath tumor of the vestibulocochlear nerve and brainstem: multimodality treatment with survival of 27 months. A case report and review of the literature.

BACKGROUND AND IMPORTANCE: Malignant peripheral nerve sheath tumors are the most common malignant mesenchymal tumors of soft tissues, but they are very rare when found to arise from a cranial nerve and when not in association with neurofibromatosis. These tumors are highly malignant and carry a poor prognosis with survival usually less than 6 months. CLINICAL PRESENTATION: The authors report the case of a 23-year-old female with no history of phakomatoses, previous irradiation, or known genetic disorders, who presented with a malignant peripheral nerve sheath tumor of the vestibulocochlear nerve and brainstem. Multiple staged skull base approaches were carried out with maximal possible resection. Adjunctive therapies including standard radiation therapy, intensity-modulated radiation therapy, and stereotactic gamma knife radiosurgery were used with an ultimate patient survival of 27 months. CONCLUSION: To our knowledge, this is the first report describing a patient with a malignant peripheral nerve sheath tumor of the vestibulocochlear nerve and brainstem treated with staged surgical approaches in conjunction with multiple forms of radiotherapy and having a significant survival of more than 2 years.

Differentiation between intra-axial metastatic tumor progression and radiation injury following fractionated radiation therapy or stereotactic radiosurgery using MR spectroscopy, perfusion MR imaging or volume progression modeling.

OBJECTIVE: To determine the accuracy of magnetic resonance spectroscopy (MRS), perfusion MR imaging (MRP), or volume modeling in distinguishing tumor progression from radiation injury following radiotherapy for brain metastasis. METHODS: Twenty-six patients with 33 intra-axial metastatic lesions who underwent MRS (n=41) with or without MRP (n=32) after cranial irradiation were retrospectively studied. The final diagnosis was based on histopathology (n=4) or magnetic resonance imaging (MRI) follow-up with clinical correlation (n=29). Cho/Cr (choline/creatinine), Cho/NAA (choline/N-acetylaspartate), Cho/nCho (choline/contralateral normal brain choline) ratios were retrospectively calculated for the multi-voxel MRS. Relative cerebral blood volume (rCBV), relative peak height (rPH) and percentage of signal-intensity recovery (PSR) were also retrospectively derived for the MRPs. Tumor volumes were determined using manual segmentation method and analyzed using different volume progression modeling. Different ratios or models were tested and plotted on the receiver operating characteristic curve (ROC), with their performances quantified as area under the ROC curve (AUC). MRI follow-up time was calculated from the date of initial radiotherapy until the last MRI or the last MRI before surgical diagnosis. RESULTS: Median MRI follow-up was 16 months (range: 2-33). Thirty percent of lesions (n=10) were determined to be radiation injury; 70% (n=23) were determined to be tumor progression. For the MRS, Cho/nCho had the best performance (AUC of 0.612), and Cho/nCho >1.2 had 33% sensitivity and 100% specificity in predicting tumor progression. For the MRP, rCBV had the best performance (AUC of 0.802), and rCBV >2 had 56% sensitivity and 100% specificity. The best volume model was percent increase (AUC of 0.891); 65% tumor volume increase had 100% sensitivity and 80% specificity. CONCLUSION: Cho/nCho of MRS, rCBV of MRP, and percent increase of MRI volume modeling provide the best discrimination of intra-axial metastatic tumor progression from radiation injury for their respective modalities. Cho/nCho and rCBV appear to have high specificities but low sensitivities. In contrast, percent volume increase of 65% can be a highly sensitive and moderately specific predictor for tumor progression after radiotherapy. Future incorporation of 65% volume increase as a pretest selection criterion may compensate for the low sensitivities of MRS and MRP.

Longitudinal assessment of quality of life and audiometric test outcomes in vestibular schwannoma patients treated with gamma knife surgery.

OBJECTIVE: To prospectively assess the quality of life (QOL) and hearing acuity in vestibular schwannoma (VS) patients after gamma knife surgery (GKS). PATIENTS: Fifty-nine VS patients. INTERVENTION: GKS. MAIN OUTCOME MEASURES: Prospective follow-up algorithm included 36-item Short Form Health Survey (SF-36), Hearing Handicap Inventory (HHI), Dizziness Handicap Inventory (DHI), Tinnitus Handicap Inventory (THI), pure-tone average, and speech discrimination hearing scores (Gardner-Robertson and American Academy of Otolaryngology), performed before and after GKS at 1-, 3-, 6-, 12-, and 18-month posttreatment intervals. RESULTS: From December 2006 to November 2008, 59 VS patients were treated with a median follow-up of 15 months. At baseline, mean scores for SF-36, HHI, DHI, and THI were 73, 37, 17, and 23, respectively. Median baseline Gardner-Robertson and American Academy of Otolaryngology hearing acuity scores were 2 and B, respectively. No significant decline in SF-36 health survey was noted after GKS. Mean SF-36 score at baseline was 73, compared with a range of 70 to 77 at predetermined posttreatment intervals. Similarly, no significant changes in DHI, HHI, and THI were noted. Approximately 47% of patients with baseline serviceable hearing maintained serviceable hearing at 12 months. Significant acute and chronic worsening in hearing acuity were noted at 1 and 18 months, respectively. No correlative decline in QOL was noted as assessed by SF-36 or HHI. CONCLUSION: No significant decline in global QOL occurred after GKS with relatively short follow-up and approximately 50% survey completion. When discussing therapy options with VS patients, anticipated treatment-related QOL outcomes should be considered.