Gompel, Jamie J. Van

Abstract Please see the full-text version of this guideline (https://www.cns.org/guidelines/guidelines-management-patients-vestibular-schwannoma/chapter_8) for the target population of each recommendation listed below. QUESTION 1 What surgical approaches for vestibular schwannomas (VS) are best for complete resection and facial nerve (FN) preservation when serviceable hearing is present? RECOMMENDATION There is insufficient evidence to support the superiority of either the middle fossa (MF) or the retrosigmoid (RS) approach for complete VS resection and FN preservation when serviceable hearing is present. QUESTION 2 Which surgical approach (RS or translabyrinthine [TL]) for VS is best for complete resection and FN preservation when serviceable hearing is not present? RECOMMENDATION There is insufficient evidence to support the superiority of either the RS or the TL approach for complete VS resection and FN preservation when serviceable hearing is not present. QUESTION 3 Does VS size matter for facial and vestibulocochlear nerve preservation with surgical resection? RECOMMENDATION Level 3: Patients with larger VS tumor size should be counseled about the greater than average risk of loss of serviceable hearing. QUESTION 4 Should small intracanalicular tumors (<1.5 cm) be surgically resected? RECOMMENDATION There are insufficient data to support a firm recommendation that surgery be the primary treatment for this subclass of VSs. QUESTION 5 Is hearing preservation routinely possible with VS surgical resection when serviceable hearing is present? RECOMMENDATION Level 3: Hearing preservation surgery via the MF or the RS approach may be attempted in patients with small tumor size (<1.5 cm) and good preoperative hearing. QUESTION 6 When should surgical resection be the initial treatment in patients with neurofibromatosis type 2 (NF2)? RECOMMENDATION There is insufficient evidence that surgical resection should be the initial treatment in patients with NF2. QUESTION 7 Does a multidisciplinary team, consisting of neurosurgery and neurotology, provides the best outcomes of complete resection and facial/vestibulocochlear nerve preservation for patients undergoing resection of VSs? RECOMMENDATION There is insufficient evidence to support stating that a multidisciplinary team, usually consisting of a neurosurgeon and a neurotologist, provides superior outcomes compared to either subspecialist working alone. QUESTION 8 Does a subtotal surgical resection of a VS followed by stereotactic radiosurgery (SRS) to the residual tumor provide comparable hearing and FN preservation to patients who undergo a complete surgical resection? RECOMMENDATION There is insufficient evidence to support subtotal resection (STR) followed by SRS provides comparable hearing and FN preservation to patients who undergo a complete surgical resection. QUESTION 9 Does surgical resection of VS treat preoperative balance problems more effectively than SRS? RECOMMENDATION There is insufficient evidence to support either surgical resection or SRS for treatment of preoperative balance problems. QUESTION 10 Does surgical resection of VS treat preoperative trigeminal neuralgia more effectively than SRS? RECOMMENDATION Level 3: Surgical resection of VSs may be used to better relieve symptoms of trigeminal neuralgia than SRS. QUESTION 11 Is surgical resection of VSs more difficult (associated with higher facial neuropathies and STR rates) after initial treatment with SRS? RECOMMENDATION Level 3: If microsurgical resection is necessary after SRS, it is recommended that patients be counseled that there is an increased likelihood of a STR and decreased FN function. The full guideline can be found at: https://www.cns.org/guidelines/guidelines-management-patients-vestibular-schwannoma/chapter_8.

Abstract BACKGROUND When clinical presentation, laboratory studies, or imaging cannot diagnose cavernous sinus (CS) and/or Meckel's cave (MC) lesions, biopsy may be necessary. OBJECTIVE To review our institutional series of biopsies of indeterminate CS and MC lesions. METHODS Records from January 1994 to June 2016 were searched for biopsied indeterminate CS and MC lesions. We defined indeterminate as having an atypical imaging appearance or a broad differential and the need for tissue for definitive diagnosis. We defined primary tumors as originating from cells inherent or near the CS and MC. RESULTS Eighty-five patients were included (median age 59 [2-85] yr); 22 (28%) had a cancer history. Approaches included frontotemporal craniotomy (n = 48, 56%), endoscopic endonasal (n = 20, 24%), percutaneous transforamen ovale (n = 12, 14%), or retrosigmoid craniotomy (n = 5, 6%). Final diagnosis was metastatic in 27 (32%), primary in 21 (25%), inflammatory in 13 (15%), hematologic in 11 (13%), fungal in 5 (5%), and nondefinitive or nondiagnostic in 8 (10%) patients. Thirteen (59%) patients with a cancer history (n = 22) had a diagnosis consistent with their prior cancer; the remaining had a second pathology (n = 6, 27%) or nondiagnostic biopsy (n = 3, 14%). Two patients had surgical complications resulting in death. CONCLUSION In this patient cohort, metastatic tumors were the most likely pathology. The biopsy threshold should be lower in patients with a cancer history if clinical or radiographic diagnosis is uncertain as 27% had a second disease. However, we consider biopsy as a last resort because the risk of major morbidity/mortality, while low, is not zero.

OBJECTIVEEpilepsy surgery is effective for lesional epilepsy, but it can be associated with significant morbidity when seizures originate from eloquent cortex that is resected. Here, the objective was to describe chronic subthreshold cortical stimulation and evaluate its early surgical safety profile in adult patients with epilepsy originating from seizure foci in cortex that is not amenable to resection.METHODSAdult patients with focal drug-resistant epilepsy underwent intracranial electroencephalography monitoring for evaluation of resection. Those with seizure foci in eloquent cortex were not candidates for resection and were offered a short therapeutic trial of continuous subthreshold cortical stimulation via intracranial monitoring electrodes. After a successful trial, electrodes were explanted and permanent stimulation hardware was implanted.RESULTSTen patients (6 males) who underwent chronic subthreshold cortical stimulation between 2014 and 2016 were included. Based on radiographic imaging, intracranial pathologies included cortical dysplasia (n = 3), encephalomalacia (n = 3), cortical tubers (n = 1), Rasmussen encephalitis (n = 1), and linear migrational anomaly (n = 1). The duration of intracranial monitoring ranged from 3 to 20 days. All patients experienced an uneventful postoperative course and were discharged home with a median length of stay of 10 days. No postoperative surgical complications developed (median follow-up length 7.7 months). Seizure severity and seizure frequency improved in all patients.CONCLUSIONSThe authors’ institutional experience with this small group shows that chronic subthreshold cortical stimulation can be safely and effectively performed in appropriately selected patients without postoperative complications. Future investigation will provide further insight to recently published results regarding mechanism and efficacy of this novel and promising intervention.

Objective Olfactory preservation after resection of esthesioneuroblastoma (ENB) has been reported, however, the ability to predict tumor involvement of the olfactory system is critical to this surgical strategy. This study aims to answer the question: Can a surgeon predict, based on preoperative imaging, whether there is unilateral involvement of the olfactory system allowing for safe attempt of olfactory preservation? Methods This is a retrospective review of post-resection ENB meeting inclusion criteria of having bilateral olfactory tracts and bulbs submitted at the time of primary resection for pathologic margins. Five board-certified skull base surgeons blinded to the pathology individually reviewed the preoperative MRI scans to predict degree of tumor involvement. Results Olfactory bulb involvement occurred in both bulbs in 35% of cases and unilateral in 39% of cases, and there was no involvement in 26% of cases sampled. When comparing physician prediction of involved tracts or bulbs, involvement was appropriate or over-called (i.e., called positive when pathology was in fact negative) in 96% of cases. Conclusion This study demonstrates unilateral or no pathologic olfactory involvement of the olfactory system in 65% of cases. Our ability to predict this involvement, which may allow for a management strategy that attempts to preserve olfactory function, was accurate at 96%. Therefore, interpretation of imaging and proceeding with smell preservation in ENB appears reasonable in this cohort.Level of Evidence: Level 2b.

ObjectiveTo determine if the laterality of primary tumors in patients with olfactory neuroblastoma (ONB) influenced the pattern and development of neck disease.MethodsUsing a retrospective cohort study design from 1994 to 2015, the primary tumors of patients who either presented with or developed neck disease were volumetrically analyzed using iPlan software (version 3.0.0, BrainLAB, Feldkirchen, Germany) by two independent observers. Agreement of volume‐derived sidedness was assessed with a kappa statistic, whereas agreement in volume‐derived degree of tumor laterality was evaluated with an intraclass correlation coefficient. A one‐sample t test was used to assess the difference in dominant percentage between the two observers.ResultsSixty‐one patients with histological diagnosis and treatment of ONB at our institution were identified. Twenty‐four patients exhibited neck involvement, 13 of whom could be volumetrically analyzed. Tumors that were greater than 75% eccentric to one side all exhibited contralateral disease, whereas the majority of unilateral neck disease was associated with relatively midline masses. Within the entire cohort, ipsilateral level 2 lymph nodes displayed the highest involvement (83%, 20 of 24), followed by ipsilateral level 1 (54%, 13 of 24), contralateral level 2 (46%, 11 of 24), contralateral level 1 (21%, 5 of 24), and ipsilateral level 3 (21%, 5 of 24).ConclusionIpsilateral neck involvement frequently was observed; however, the degree of ONB primary site laterality did not appear to have implications on the development of contralateral neck disease. Therefore, when considering elective therapy to the neck, ONB laterality should not be used to justify unilateral neck treatment.Level of Evidence4. Laryngoscope, 128:864–870, 2018

Background: The first description of the voluntary motor function of the facial nerve and separate sensory-motor contributions of the trigeminal nerve is most commonly attributed to Charles Bell. However, a review of the original scientific accounts and subsequent historical publications question the validity of this credit. The objective of the present historical analysis is to clarify the contributions of Herbert Mayo toward discovering the functions of the fifth and seventh cranial nerves and to raise awareness of this historical controversy within the medical literature. Methods: Review of Charles Bell's and Herbert Mayo's original dissertations published between 1821 and 1823, and subsequent reports relevant to these primary works. Results: Bell's submissions to the Royal Society of London in 1821 and 1822 describe the seventh nerve as the “respiratory nerve of the face” responsible for involuntary coordination of facial movement with the organs of respiration. Separately, Bell states that the fifth nerve is responsible for sensibility and voluntary movement of the facial muscles. In these accounts, Bell only peripherally alludes to the motor function of the seventh nerve and often comments inaccurately on fifth and seventh cranial nerve innervation. In contrast, in 1822 and 1823, Herbert Mayo first accurately and unequivocally defined the voluntary motor function of the facial nerve and sensory-motor function of the trigeminal nerve on the basis of his detailed experiments. The ultimate transfer of acknowledgment to Bell was rooted in surreptitious reworking of Bell's original dissertations and personal attacks against Mayo rather than arguments of scientific merit. Conclusion: Several notable clinicians and anatomists have contributed to our current understanding of the anatomy and physiology of the facial and trigeminal nerves, including Charles Bell; however, Herbert Mayo should be remembered for first providing a more accurate and clear description of their separate functions.

Abstract Dr Albert L. Rhoton Jr became the focal point of neurosurgery's evolution in understanding the intricate and complex microanatomy of the human brain over the last 4 decades. His pioneering work on cadaveric specimens proved to be a pivotal endeavor in the pursuit to better understand the complex microsurgical anatomy of cranial surgery. This paper details his early career at the Mayo Clinic in Rochester, Minnesota. A comprehensive review and synthesis of data acquired from the institutional historical archives including the Annual Reports to the Executive Committee, the Reports to the Board of Directors, the MAYOVOX Newsletter, the illustration archives of the Mayo Clinic Division of Creative Media, staff biographies, curriculum vitae, personal interviews, as well as full-text journal articles, and book publications was performed. Dr Rhoton was engaged in a busy clinical practice as a young staff at the Mayo Clinic. Records show he focused on tackling complex intracranial pathologies along with numerous basic research and neuroanatomy projects that became a major part of his life's work and passion. He was a great teacher and friend to countless individuals and his work will continue to impact and improve the care provided to neurosurgery patients for generations to come.

Objectives We examined vestibular schwannoma tumor dimension and direction of growth to determine whether these correlate with facial nerve outcome as well as extent of resection (EOR). Design Retrospective review of prospectively maintained databases. Participants 206 patients were a part of this study. Main Outcome Measures Tumor dimensions were measured using preoperative magnetic resonance imaging, and a series of ratios were then calculated to further characterize tumor dimension. Regression analyses were performed to investigate correlation with facial nerve outcome and EOR. Results Patients with tumor extending >1.5 cm anterior to the internal auditory canal (IAC) (AB measurement) were three times more likely to have postoperative House-Brackman grades of 3 or worse. We also found that an EB/BF ratio (representing elongated growth parallel to the IAC axis) ≥1.1 was associated with half the risk of poor facial nerve outcome. Tumors with anterior-posterior diameter (AC measurement) >1.9 cm were five times less likely to undergo gross total resection (GTR). Furthermore, an increased degree of tumor extension into the IAC (DE measurement >2.4 cm) or an increased amount of brainstem compression (EB measurement >1.1 cm) were each associated with a nearly 3-fold decrease in the likelihood of GTR. Conclusion Our study demonstrates that anterior extent of the tumor is as important as tumor size to facial nerve outcome and degree of resection for vestibular schwannomas.

OBJECTIVETemporal lobectomy is a well-established treatment modality for the management of medically refractory epilepsy in appropriately selected patients. The aim of this study was to assess 30-day morbidity and mortality after temporal lobectomy in cases registered in a national database.METHODSA retrospective cohort analysis was conducted using a multiinstitutional surgical registry compiled between 2006 and 2014. The authors identified patients who underwent anterior temporal lobectomy and/or amygdalohippocampectomy for a primary diagnosis of intractable epilepsy. Univariate and multivariable analyses with regard to patient demographics, comorbidities, operative characteristics, and 30-day outcomes were applied.RESULTSA total of 216 patients were included in the study. The median age was 38 years and 46% of patients were male. The median length of stay was 3 days and the 30-day mortality rate was 1.4%. Fourteen patients (6.5%) developed at least one major complication. Return to the operating room was observed in 7 patients (3.2%). Readmission within 30 days and discharge to a location other than home were available for 2011–2014 (n = 155) and occurred in 11% and 10.3% of patients, respectively. Multivariable regression analysis revealed that increasing age was an independent predictor of discharge disposition other than home and that male sex was a significant risk factor for the development of a major complication. Interestingly, the presence of the attending neurosurgeon and a resident during the procedure was significantly associated with decreased odds of prolonged length of stay (i.e., > 75th percentile [5 days]) and discharge to a location other than home.CONCLUSIONSUsing a multiinstitutional surgical registry, 30-day outcome data after temporal lobectomy for medically intractable epilepsy demonstrates a mortality rate of 1.4%, a major complication rate of 6.5%, and a readmission rate of 11%. Temporal lobectomy is an extremely effective therapy for seizures originating there—however, surgical intervention must be weighed against its morbidity and mortality outcomes.