Shervin Rahimpour

Glioblastoma in the elderly: the effect of aggressive and modern therapies on survival

OBJECTIVE The prognosis of elderly patients with glioblastoma (GBM) is universally poor. Currently, few studies have examined postoperative outcomes and the effects of various modern therapies such as bevacizumab on survival in this patient population. In this study, the authors evaluated the effects of various factors on overall survival in a cohort of elderly patients with newly diagnosed GBM. METHODS A retrospective review was performed of elderly patients (≥ 65 years old) with newly diagnosed GBM treated between 2004 and 2010. Various characteristics were evaluated in univariate and multivariate stepwise models to examine their effects on complication risk and overall survival. RESULTS A total of 120 patients were included in the study. The median age was 71 years, and sex was distributed evenly. Patients had a median Karnofsky Performance Scale (KPS) score of 80 and a median of 2 neurological symptoms on presentation. The majority (53.3%) of the patients did not have any comorbidities. Tumors most frequently (43.3%) involved the temporal lobe, followed by the parietal (35.8%), frontal (32.5%), and occipital (15.8%) regions. The majority (57.5%) of the tumors involved eloquent structures. The median tumor size was 4.3 cm. Every patient underwent resection, and 63.3% underwent gross-total resection (GTR). The vast majority (97.3%) of the patients received the postoperative standard of care consisting of radiotherapy with concurrent temozolomide. The majority (59.3%) of patients received additional agents, most commonly consisting of bevacizumab (38.9%). The median survival for all patients was 12.0 months; 26.7% of patients experienced long-term (≥ 2-year) survival. The extent of resection was seen to significantly affect overall survival; patients who underwent GTR had a median survival of 14.1 months, whereas those who underwent subtotal resection had a survival of 9.6 months (p = 0.038). Examination of chemotherapeutic effects revealed that the use of bevacizumab compared with no bevacizumab (20.1 vs 7.9 months, respectively; p < 0.0001) and irinotecan compared with no irinotecan (18.0 vs 9.7 months, respectively; p = 0.027) significantly improved survival. Multivariate stepwise analysis revealed that older age (hazard ratio [HR] 1.06 [95% CI1.02-1.10]; p = 0.0077), a higher KPS score (HR 0.97 [95% CI 0.95-0.99]; p = 0.0082), and the use of bevacizumab (HR 0.51 [95% CI 0.31-0.83]; p = 0.0067) to be significantly associated with survival. CONCLUSION This study has demonstrated that GTR confers a modest survival benefit on elderly patients with GBM, suggesting that safe maximal resection is warranted. In addition, bevacizumab significantly increased the overall survival of these elderly patients with GBM; older age and preoperative KPS score also were significant prognostic factors. Although elderly patients with GBM have a poor prognosis, they may experience enhanced survival after the administration of the standard of care and the use of additional chemotherapeutics such as bevacizumab.

Enhancing Nervous System Recovery through Neurobiologics, Neural Interface Training, and Neurorehabilitation

After an initial period of recovery, human neurological injury has long been thought to be static. In order to improve quality of life for those suffering from stroke, spinal cord injury, or traumatic brain injury, researchers have been working to restore the nervous system and reduce neurological deficits through a number of mechanisms. For example, neurobiologists have been identifying and manipulating components of the intra- and extracellular milieu to alter the regenerative potential of neurons, neuro-engineers have been producing brain-machine and neural interfaces that circumvent lesions to restore functionality, and neurorehabilitation experts have been developing new ways to revitalize the nervous system even in chronic disease. While each of these areas holds promise, their individual paths to clinical relevance remain difficult. Nonetheless, these methods are now able to synergistically enhance recovery of native motor function to levels which were previously believed to be impossible. Furthermore, such recovery can even persist after training, and for the first time there is evidence of functional axonal regrowth and rewiring in the central nervous system of animal models. To attain this type of regeneration, rehabilitation paradigms that pair cortically-based intent with activation of affected circuits and positive neurofeedback appear to be required—a phenomenon which raises new and far reaching questions about the underlying relationship between conscious action and neural repair. For this reason, we argue that multi-modal therapy will be necessary to facilitate a truly robust recovery, and that the success of investigational microscopic techniques may depend on their integration into macroscopic frameworks that include task-based neurorehabilitation. We further identify critical components of future neural repair strategies and explore the most updated knowledge, progress, and challenges in the fields of cellular neuronal repair, neural interfacing, and neurorehabilitation, all with the goal of better understanding neurological injury and how to improve recovery.

Surgical Options for Atypical Facial Pain Syndromes

Atypical neuropathic facial pain is a syndrome of intractable and unremitting facial pain that is secondary to nociceptive signaling in the trigeminal system. These syndromes are often recalcitrant to pharmacotherapy and other common interventions, including microvascular decompression and percutaneous procedures. Herein, the authors present two other viable approaches (nucleus caudalis dorsal root entry zone lesioning and motor cortex stimulation), their indications, and finally a possible treatment algorithm to consider when assessing patients with atypical facial pain.

Rates and predictors of success and failure in repeat epilepsy surgery: A meta‐analysis and systematic review

Medically refractory epilepsy is a debilitating disorder that is particularly challenging to treat in patients who have already failed a surgical resection. Evidence regarding outcomes of further epilepsy surgery is limited to small case series and reviews. Therefore, our group performed the first quantitative meta‐analysis of the literature from the past 30 years to assess for rates and predictors of successful reoperations.

Drivers and Risk Factors of Unplanned 30-Day Readmission Following Spinal Cord Stimulator Implantation

Unplanned 30‐day readmission rates contribute significantly to growing national healthcare expenditures. Drivers of unplanned 30‐day readmission after spinal cord stimulator (SCS) implantation are relatively unknown. The aim of this study was to determine drivers of 30‐day unplanned readmission following SCS implantation.

Microsurgical resection of vestibular schwannomas: complication avoidance

Vestibular schwannoma (VS) surgery requires appropriate patient selection, meticulous microsurgical technique and optimal post-operative care. Focused radiation is an effective alternative for the treatment of smaller VSs. For VS surgery to remain a reasonable option, surgery must be performed with a limited number of complications. Complication rates for VS surgery have increased over the last decade. This is likely due to (1) decreased surgical volume and as a result decreased microsurgical experience, (2) larger tumors undergoing surgery while smaller tumors are reserved for radiation, and (3) surgery for previously radiated tumors resulting in more difficult anatomic dissection. Appropriate management of complications is paramount. Herein, we discuss complications related to VS microsurgery and methods of avoidance. Specifically, we discuss the most frequently encountered complications, intraoperative monitoring and finally, methods of addressing these complications. With meticulous microsurgical technique, careful intraoperative monitoring and vigilant perioperative care one will ensure optimal patient outcomes.

Integrating Molecular, Cellular, and Systems Approaches to Repairing the Brain After Stroke

A stroke implies a sudden and spontaneous onset of neurological symptoms due to a vascular insult. Despite the brain’s inherent capacity for plasticity and spontaneous improvement, strokes still leave many patients with devastating deficits that can permanently affect independence and quality of life. This chapter focuses on ways to help restore the functionality of the central nervous system (CNS) after this type of injury. Understanding how neurons interact on both individual (i.e. cellular and molecular) and population (i.e. synapses and circuits) levels is crucial to developing successful restorative strategies, as is appreciating how these interactions change over the injury-recovery timeline. The CNS has several characteristics that make its restitution exceptionally difficult; beyond even its incredible intricacy, its parenchymal cells, or neurons, do not regenerate well after injury, and this damaged neuronal substrate embodies a consciousness system that must be engaged in its own recovery. In fact, there is now data suggesting that conscious intention, often invoked through goal-oriented rehabilitation, plays a crucial role in facilitating functional plasticity and long-range axonal sprouting. To capitalize on this principle, neural interfaces and electrical stimulation strategies are being integrated into rehabilitation paradigms to provide critically-timed feedback that can reinvigorate injured circuits. Combining these approaches with interventions at the cellular and molecular level (e.g. immunological or genetic modulations aimed at promoting neuronal outgrowth, or stem cells that can replace damaged parenchyma) has the chance to improve neurological recovery to back toward baseline levels. Ultimately, because cells of the CNS do not regrow on their own, and because regrowth and synapse formation does not necessarily ensure restoration of function, harmonious application of synergistic approaches at both the micro- and macroscopic levels will be needed to establish long-lasting functional plasticity and meaningful recovery.

Toward Functional Restoration of the Central Nervous System: A Review of Translational Neuroscience Principles

Injury to the central nervous system (CNS) can leave patients with devastating neurological deficits that may permanently impair independence and diminish quality of life. Recent insights into how the CNS responds to injury and reacts to critically timed interventions are being translated into clinical applications that have the capacity to drastically improve outcomes for patients suffering from permanent neurological deficits due to spinal cord injury, stroke, or other CNS disorders. The translation of such knowledge into practical and impactful treatments involves the strategic collaboration between neurosurgeons, clinicians, therapists, scientists, and industry. Therefore, a common understanding of key neuroscientific principles is crucial. Conceptually, current approaches to CNS revitalization can be divided by scale into macroscopic (systems-circuitry) and microscopic (cellular-molecular). Here we review both emerging and well-established tenets that are being utilized to enhance CNS recovery on both levels, and we explore the role of neurosurgeons in developing therapies moving forward. Key principles include plasticity-driven functional recovery, cellular signaling mechanisms in axonal sprouting, critical timing for recovery after injury, and mechanisms of action underlying cellular replacement strategies. We then discuss integrative approaches aimed at synergizing interventions across scales, and we make recommendations for the basis of future clinical trial design. Ultimately, we argue that strategic modulation of microscopic cellular behavior within a macroscopic framework of functional circuitry re-establishment should provide the foundation for most neural restoration strategies, and the early involvement of neurosurgeons in the process will be crucial to successful clinical translation.