Foundations in Spinal Endoscopy.

Spinal endoscopy has revolutionized the way spine surgeons deliver minimally invasive care for appropriately selected patients. The evolution of endoscopy has been tumultuous since its beginnings as a "blind" percutaneous procedure to access the disk until the present state, in which complex decompressions and even fusions can be accomplished through subcentimeter incisions. Engineering has played a crucial role in this evolution with advances in optics, illumination, and instrumentation that have allowed surgeons to work safely and efficiently in smaller and smaller corridors. Finally, the adaptation of enhanced recovery after surgery protocols have complemented the benefits offered by spinal endoscopy to help patients return to the quality of life they seek through surgical intervention. In this article, we explore foundational elements of spinal endoscopy and look ahead to the future of this maturing field.

Applications of augmented reality in the neurosurgical operating room: A systematic review of the literature.

Advancements in imaging techniques are key forces of progress in neurosurgery. The importance of accurate visualization of intraoperative anatomy cannot be overemphasized and is commonly delivered through traditional neuronavigation. Augmented Reality (AR) technology has been tested and applied widely in various neurosurgical subspecialties in intraoperative, clinical use and shows promise for the future. This systematic review of the literature explores the ways in which AR technology has been successfully brought into the operating room (OR) and incorporated into clinical practice. A comprehensive literature search was performed in the following databases from inception-April 2020: Ovid MEDLINE, Ovid EMBASE, and The Cochrane Library. Studies retrieved were then screened for eligibility against predefined inclusion/exclusion criteria. A total of 54 articles were included in this systematic review. The studies were sub- grouped into brain and spine subspecialties and analyzed for their incorporation of AR in the neurosurgical clinical setting. AR technology has the potential to greatly enhance intraoperative visualization and guidance in neurosurgery beyond the traditional neuronavigation systems. However, there are several key challenges to scaling the use of this technology and bringing it into standard operative practice including accurate and efficient brain segmentation of magnetic resonance imaging (MRI) scans, accounting for brain shift, reducing coregistration errors, and improving the AR device hardware. There is also an exciting potential for future work combining AR with multimodal imaging techniques and artificial intelligence to further enhance its impact in neurosurgery.

Historical Aspects of Stereotactic Radiosurgery: Concepts, People, and Devices.

Stereotactic radiosurgery is a modern discipline that emerged after World War II. It represents a synthesis of an approach to patient care that was not immediately embraced by either neurosurgeons or radiation oncologists, but which has been shown, time and again, to be advantageous for the treatment of intracranial pathology. Indeed, stereotactic radiosurgical techniques are now being rapidly adapted and adopted for the treatment of extracranial malignant and benign disease. Any examination of the individuals, devices, and technological advances that permitted stereotactic radiosurgery to become a preferred approach for patient care cannot be absolutely comprehensive but can provide insights into the evolution of the specialty and potential future prospects for further improvements in patient care. As Shakespeare wrote in The Tempest, "What's past is prologue."

Worldwide Access to Stereotactic Radiosurgery.

Stereotactic radiosurgery is a safe and effective technology that can address a variety of neurosurgical conditions, but in many parts of the world, access remains an issue. Although the technology is increasingly available in the United States, Canada, Europe, and parts of Asia, poor access to central nervous system (CNS) imaging and inadequate treatment equipment in other parts of the world limit the availability of radiosurgery as a treatment option. In addition, epidemiologic data about cancer and CNS metastases in low-income countries are sparse and much less complete than in more developed countries, and the need for radiosurgery may be underestimated as a result. Current radiosurgical platforms can be expensive to install and require a substantial amount of personnel training for safe operation. Socioeconomic and political forces are relevant to limitations to and opportunities for improving access to care. Here we examine the current barriers to access and propose areas for future efforts to improve global availability of radiosurgery for neurosurgical conditions.

De Novo Mutation in Genes Regulating Neural Stem Cell Fate in Human Congenital Hydrocephalus.

Congenital hydrocephalus (CH), featuring markedly enlarged brain ventricles, is thought to arise from failed cerebrospinal fluid (CSF) homeostasis and is treated with lifelong surgical CSF shunting with substantial morbidity. CH pathogenesis is poorly understood. Exome sequencing of 125 CH trios and 52 additional probands identified three genes with significant burden of rare damaging de novo or transmitted mutations: TRIM71 (p = 2.15 × 10-7), SMARCC1 (p = 8.15 × 10-10), and PTCH1 (p = 1.06 × 10-6). Additionally, two de novo duplications were identified at the SHH locus, encoding the PTCH1 ligand (p = 1.2 × 10-4). Together, these probands account for ∼10% of studied cases. Strikingly, all four genes are required for neural tube development and regulate ventricular zone neural stem cell fate. These results implicate impaired neurogenesis (rather than active CSF accumulation) in the pathogenesis of a subset of CH patients, with potential diagnostic, prognostic, and therapeutic ramifications.

Theoretical Basis of Vagus Nerve Stimulation.

Despite a myriad of medical and surgical treatments for epilepsy developed over the past few decades, a large subset of patients remains refractory to treatment. Over this time period, vagus nerve stimulation (VNS) has become an accepted and viable treatment modality for this population. Since the earliest report of VNS implantation in 1988, tens of thousands of patients worldwide have received VNS therapy, and >100,000 patient-years of experience have been accrued. The mechanisms underlying the response to VNS therapy continue to be elucidated. As understanding of the VNS mechanisms of action continues to grow, more pathologies will arise as potential treatment indications. Furthermore, current treatment populations with refractory epilepsy, depression, and inflammatory diseases may enjoy improved response to stimulation.

The current status of endoscopy in transsphenoidal surgery: an international survey.

OBJECTIVE: A survey-based study was designed to assess opinions related to transsphenoidal endoscopy, to evaluate the current global attitudes of neurosurgeons regarding the use of this procedure, and to solicit basic data from key institutions worldwide, with the advantage that large series of cases become available for analysis. METHODS: A web-based multi-item questionnaire was distributed to the surgical departments of 393 neurosurgical centers by means of an invitation e-mail. The questionnaire was composed of 2 sections: section 1 focused on the surgical technique for pituitary adenomas (standard technique), and section 2 concentrated on surgery for skull base tumors (extended technique). Each section was composed of 2 parts: multiple choice questions and free textual responses. RESULTS: From a total of 393 neurosurgical centers, from 23 countries, that received the questionnaire, 87 of them (22%) submitted complete or incomplete responses. The surgical procedure, in 60 cases had been performed by a neurosurgeon, in 53 cases by a neurosurgeon and an otolaryngologist, and in 4 cases by an otolaryngologist only. The endoscope (2- and 3-dimensional) was used in 85.2% of transsphenoidal procedures versus the microscope in 14.8% of cases. The endonasal route was used for approach in 93.2% versus the sublabial route in 6.8% of cases. Computer-guided navigation was used by survey population in 71 cases, micro-Doppler in 51 cases, and Cavitron Ultrasonic Surgical Aspirator in 43 cases. Several hundreds of extrasellar tumors were operated using the extended technique. CONCLUSIONS: Transsphenoidal endoscopy for pituitary and anterior skull base tumors has become established as a routine method of dealing with a variety of lesions. The level of interest in the neurosurgical surgery community is reflected by the geometric expansion of contributions to the literature on endoscopic surgery.

Evolving societal risks and necessary precautions in the age of nuclear power and therapeutic radiation: an American perspective.

Terrorism involving nuclear or radiologic weapons can devastate populations, city infrastructures, and entire sociopolitical systems. In our age of nuclear medicine and therapeutic radiation delivery, the unauthorized and illegal acquisition of radioactive materials needed for such an attack is always a possibility and risk. Physicians handling high-energy isotopes for medical radiotherapy must be aware of the basic security requirements as outlined by the Nuclear Regulation Commission, which include background checks and authorized access, physical protection during radionuclide use, and physical protection during its transit. The Leksell Gamma Knife and its Category 1 cobalt-60 radioactive source are discussed because of their significant potential for deployment in a weaponized device. Although this article presents a perspective relating to American rules and regulations, these precautions are applicable anywhere that similar situations exist. Understanding these materials and the security they require is essential to preventing the disastrous outcomes should these isotopes fall into terrorists' hands.

Radiosurgery for metastatic disease at the craniocervical junction.

OBJECTIVE: Metastatic disease of the craniovertebral junction (CVJ) can cause pain, cranial nerve deficits, occipitocervical instability, or brainstem/spinal cord compression if left untreated. Many patients with metastasis in this region have a high burden of systemic disease and short life expectancy, making them poor candidates for aggressive surgical resections and fusion procedures. Traditionally, symptom palliation and local disease control in these patients has been achieved through conventional radiation therapy. Stereotactic radiosurgery (SRS) has the advantage of precisely delivering radiation to a target in fewer fractions. To our knowledge, we report the results of the largest series of patients with CVJ metastasis treated with stereotactic radiosurgery. METHODS: We performed a retrospective review of 9 consecutive patients with 10 tumors of the CVJ treated with SRS at the Keck Medical Center of the University of Southern California. Two tumors were treated with Gamma Knife, whereas the other 8 received CyberKnife. RESULTS: The median marginal dose was 20 Gy (16-24 Gy) over 1-5 fractions. Point maximal dose to the brainstem or spinal cord ranged between 8 and 18.9 Gy. Median survival was 4 months (1-51 months). Five of six patients presenting with pain had at least partial symptom resolution. No patient went on to require surgical decompression or fusion, and there were no complications directly related to SRS. CONCLUSIONS: In well-selected patients, SRS for metastatic lesions of the CVJ has a low risk for complications or treatment failure, while achieving a high rate of palliation of pain symptoms.

Focused ultrasound: relevant history and prospects for the addition of mechanical energy to the neurosurgical armamentarium.

Although the concept of focused ultrasonography emerged more than 70 years ago, the need for a craniectomy obviated its development as a noninvasive technology. Since then advances in phased array transducers and magnetic resonance imaging technology have resurrected the ultrasound as a noninvasive therapeutic for a plethora of neurological conditions ranging from embolic stroke and intracranial hemorrhage to movement disorders and brain neoplasia. In the same way that stereotactic radiosurgery has fundamentally changed the scope and treatment paradigms of tumor and specifically skull base surgery, focused ultrasound has a similar potential to revolutionize the field of neurological surgery. In addition, focused ultrasound comes without the general complexity or the risks of ionizing radiation that accompany radiosurgery. As the quest for minimally invasive and noninvasive therapeutics continues to define the new neurosurgery, the focused ultrasound evolves to join the neurosurgical armamentarium.

Recapitulating flesh with silicon and steel: advancements in upper extremity robotic prosthetics.

With the loss of function of an upper extremity because of stroke or spinal cord injury or a physical loss from amputation, an individual's life is forever changed, and activities that were once routine become a magnitude more difficult. Much research and effort have been put into developing advanced robotic prostheses to restore upper extremity function. For patients with upper extremity amputations, previously crude prostheses have evolved to become exceptionally functional. Because the upper extremities can perform a wide variety of activities, several types of upper extremity prostheses are available ranging from passive cosmetic limbs to externally powered robotic limbs. In addition, new developments in brain-machine interface are poised to revolutionize how patients can control these advanced prostheses using their thoughts alone. For patients with spinal cord injury or stroke, functional electrical stimulation promises to provide the most sophisticated prosthetic limbs possible by reanimating paralyzed arms of these patients. Advances in technology and robotics continue to help patients recover vital function. This article examines the latest neurorestorative technologies for patients who have either undergone amputation or lost the use of their upper extremities secondary to stroke or spinal cord injury.