Phillip A. Bonney

Seizure Freedom Rates and Prognostic Indicators After Resection of Gangliogliomas: A Review.

Gangliogliomas are rare tumors that comprise up to 40% of lesional epilepsy. Seizure control represents an important quality-of-life determinant in patients with these tumors. Here we present results of a literature review addressing rates of seizure freedom in in patients with gangliogliomas. Across studies, seizure freedom occurred in 63%-100% of patients. Many studies included follow-up times of greater than 5 years, suggesting that the responses are durable. We discuss potential prognostic factors associated with seizure freedom, including the duration of epilepsy, patient age, frequency and semiology of seizures, tumor location, extent of surgical resection, and operative strategy, including surgical approach and use of invasive monitoring. Although significant differences in study populations and treatments preclude meta-analysis, we discuss prognostic factors identified in individual studies. Increased extent of resection, lesser duration of epilepsy, and younger age at surgery have been associated with increased seizure freedom rates in at least 2 studies each. Although all studies were retrospective in nature and are consequently limited by the weaknesses inherent to such investigations, the literature suggests that surgery is able to relieve most ganglioglioma patients--regardless of patient demographics, tumor characteristics, and operative variables--of seizures.

Early Discharge After Surgery for Intra-Axial Brain Tumors

OBJECTIVE A steady trend in medicine has been discharging patients earlier after surgical procedures, a trend that has been resisted by many in the field of intracranial tumor surgery. Here we demonstrate the feasibility of discharge on postoperative days 1 or 2 for patients undergoing elective intracranial surgery. METHODS We conducted a retrospective analysis on all patients undergoing elective intracranial keyhole surgery for tumors, cysts, and other masses between January 2010 and December 2011. During this time period, we used an early discharge plan centered on the clinical appearance of the patient, for which all patients were eligible preoperatively. Patients who met discharge criteria were encouraged to continue recovery at home. RESULTS Of 313 patients, 213 (68.1%) were discharged on postoperative days 1 or 2. Within this group, 81.6% had supratentorial lesions, 16.9% had infratentorial lesions, and 1.4% had lesions extending above and below the tentorium. High grade gliomas accounted for 38.5% of lesions. No deaths or readmissions for postoperative swelling or hematomas occurred within 28 days of surgery. The overall rate of readmission for postoperative complications was 4.2%, compared with 4.0% for patients discharged on or after postoperative day 3. Readmission rate for repeat surgery addressing complications causing neurological symptoms was 1.9%. CONCLUSIONS Our data suggest that the most serious complications occur within hours of the procedure, not days. The complications requiring readmission that we observed would not have been avoided with longer inpatient courses. Thus, consideration should be given to sending well-looking patients home to recover on postoperative days 1 or 2.

Brainstem cavernous malformations resected via miniature craniotomies: Technique and approach selection

Brainstem cavernous malformations can cause devastating neurologic disability when they hemorrhage, which occurs at a higher rate in the brainstem than in other locations. Traditional access to these lesions requires a large craniotomy with extensive exposure and manipulation of vital structures. We present a case series of patients who underwent surgical resection of brainstem cavernous malformations using minimally invasive approaches at our institution from January 2012 to August 2014, all of whom had experienced at least one hemorrhage prior to presentation. Approach choice was determined by location of the cavernous malformation in relation to the brainstem surface. Resection occurred through our described standardized method. Postoperatively, there were three instances of transient neurologic symptoms, all of which resolved at time of last follow-up. All eight patients experienced neurologic improvement after surgery, with four patients showing no deficits at last follow-up. Approach selection rationale and technical nuances are presented on a case-by-case basis. With carefully planned keyhole approaches to cavernous malformations presenting to the brainstem surface, excellent results may be achieved without the necessity of larger conventional craniotomies. We believe the nuances presented may be of use to others in the surgical treatment of these lesions.

Results with Expanded Endonasal Resection of Skull Base Meningiomas Technical Nuances and Approach Selection Based on an Early Experience.

AIM Reconstruction technique advances have created renewed enthusiasm for the expanded endonasal approach (EEA). However, as with any new technique, early experiences inevitably lead to more selective use of these techniques. We reviewed our experience of the expanded endonasal endoscopic approach for skull base meningiomas and place it in context of the literature. MATERIAL AND METHODS We performed retrospective review of all endonasal cases performed at our center for histologically proven meningioma. Tumor locations in 26 patients included the olfactory groove (n=9), tuberculum sellae (n=7), optic nerve sheath (n=1), planum sphenoidale (n=2), clival (n=1) petroclival (n=3), cavernous sinus (n=2) and extensive pan-basal meningioma (n=1). RESULTS The median follow-up was 38.6 months. Excluding 3 patients with tumors found incidentally, pre-operative symptoms improved in 14 of 23 (61%), were the same in 8 of 23 (35%) and worsened in one of 23 patients (4%) at time of last follow-up. Of all 26 patients, 16 (62%) had complete macroscopic resection of their tumor, 5 (19%) underwent at least 90% resection, and 5 (19%) underwent subtotal resection. There were two neurological complications and one cerebrospinal fluid leak. CONCLUSION This study presents outcomes of patients treated with endonasal endoscopic meningioma surgery. We believe that very low rates of morbidity can be achieved in carefully selected patients, thus avoiding brain manipulation.

Proximal ventricular shunt malfunctions in children: Factors associated with failure.

Ventricular shunt failures and subsequent revisions are a significant source of patient morbidity. We conducted a review of pediatric patients undergoing placement or revision of ventricular shunts at our institution between January 2007 and December 2008. Patients were followed through to July 2014. Data collected included patient demographics, shunt history and indication for procedure, approach taken for shunt placement, and location of shunt tip in relation to the foramen of Monro. Univariate and multivariate analyses were conducted to identify factors associated with proximal failure. A total of 87 procedures were identified in 40 patients, consisting of 23 initial placements and 64 revisions. Thirty-nine proximal catheter malfunctions were identified. Indications for shunt placement included Chiari II malformation (33%) and intraventricular hemorrhage (33%). Mean follow-up period was 5.5 years. Median time to shunt failure was 1.57 years. In the multivariate model, younger age at placement was associated with decreased time to proximal failure (hazard ratio [HR]=0.80 per increasing year of age, 95% confidence interval [CI] 0.64-0.98). Both anterior approach (HR=0.39, 95% CI 0.23-0.67) and farther distance to foramen of Monro (HR=0.02 per increasing 10mm, 95% CI 0.00-0.22) were associated with increased time to proximal failure when the catheter tip was located within the contralateral lateral ventricle. Optimizing outcomes in patients with shunt-dependent hydrocephalus continues to be a challenge. Despite unsatisfactory outcomes, particularly in the pediatric population, few conclusions can be drawn from studies assessing operative variables.

Dramatic response to temozolomide, irinotecan, and bevacizumab for recurrent medulloblastoma with widespread osseous metastases

There is little evidence to guide the choice of chemotherapeutic agents for osseous metastases in medulloblastoma. Recently, triple therapy with temozolomide, irinotecan, and bevacizumab has been reported to have efficacy in recurrent medulloblastoma, and this regimen alone and in combination with other agents has been tested in several early-phase clinical trials. Here we report a 20-year-old woman with multiply-relapsed medulloblastoma with numerous osseous metastases 8 years after original diagnosis who responded dramatically to temozolomide, irinotecan, and bevacizumab therapy. This case highlights the potential for this regimen in treating osseous metastases in medulloblastoma.

The Use of the Target Cancellation Task to Identify Eloquent Visuospatial Regions in Awake Craniotomies: Technical Note.

The success of awake craniotomies relies on the patient’s performance of function-specific tasks that are simple, quick, and reproducible. Intraoperative identification of visuospatial function through cortical and subcortical mapping has utilized a variety of intraoperative tests, each with its own benefits and drawbacks. In light of this, we developed a simple software program that aids in preventing neglect by simulating a target-cancellation task on a portable electronic device. In this report, we describe the interactive target cancellation task and have reviewed seven consecutive patients who underwent awake craniotomy for parietal and/or posterior temporal infiltrating brain tumors of the non-dominant hemisphere. Each of these patients performed target cancellation and line bisection tasks intraoperatively. The outcomes of each patient and testing scenario are described. Positive intraoperative cortical and subcortical sites involved with visuospatial processing were identified in three of the seven patients using the target cancellation and confirmed utilizing the line-bisection task. No identification of visuospatial function was accomplished utilizing the line-bisection task alone. Complete visuospatial function mapping was completed in less than 10 minutes in all patients. No patients had preoperative or postoperative hemineglect. Our findings highlight the feasibility of the target cancellation technique for use during awake craniotomy to aid in avoiding postoperative hemineglect. Target cancellation may offer an alternative method of cortical and subcortical visuospatial mapping in patients unable to perform other commonly used modalities.

Histology and molecular aspects of central neurocytoma.

Central neurocytoma (CN) is a well-differentiated tumor of neural cells occurring within the ventricles. It is composed of monomorphic cells with round, regular nuclei within clear cytoplasm and must be distinguished from other clear cell tumors. Immunohistochemical markers of CN that aid in diagnosis include synaptophysin and neuronal nuclear antigen. The molecular biology of these tumors is becoming increasingly elucidated, particularly with the use of microarray analyses. Several oncogenic pathways have been suggested by these studies. Although progress continues to be made, knowledge of CN has yet to dictate targeted therapies in treating patients with these tumors.

Endoscopic Endonasal Infrapetrous Transpterygoid Approach to the Petroclival Junction for Petrous Apex Chondrosarcoma: Technical Report

Chondrosarcomas of the skull base are rare tumors that present difficult management considerations due to the pathoanatomical relationships of the tumor to adjacent structures. We present the case of a 25-year-old female patient presenting with a chondrosarcoma of the right petrous apex extending inferiorly, medial to the cranial nerves. The tumor was resected via an endoscopic endonasal infrapetrous transpterygoid approach that achieved complete resection and an excellent long-term outcome with no complications. Technical nuances and potential pitfalls of the case are discussed in depth including measures to protect the carotid artery while performing the required drilling of the skull base to access the lesion.

Operative results of keyhole supracerebellar-infratentorial approach to the pineal region

The supracerebellar-infratentorial approach to the pineal region is typically accomplished with a craniotomy that extends to at least the rim of the foramen magnum. Minimally invasive techniques that limit the inferior extent of the craniotomy have been described for this approach but, to our knowledge, no operative results have been published demonstrating the feasibility and safety of such techniques. We present a series of patients who underwent surgical resection of pineal region lesions using the minimally invasive method at our institution. Clinical, radiologic, and operative data were prospectively collected on patients treated for lesions of the pineal region by the senior author from January 2012 to July 2014. Seven patients were identified. The sitting position was employed in each patient. Keyhole craniotomies were limited to a maximum diameter of 2.5 cm. Adequate working corridors were attained, and in no patient was resection limited by the exposure. No neurological or systemic complications were seen in the perioperative and early follow-up periods. In this feasibility study, we demonstrate that it is not necessary to extend a craniotomy inferiorly to the rim of the foramen magnum in order to gain access to the pineal region via relaxation of the cerebellum. The same surgical goals can be safely accomplished with a smaller craniotomy.