Russell Meyers (1905-1999): pioneer of functional and ultrasonic neurosurgery

Magnetic Resonance-Guided focused ultrasound surgery for Parkinson's disease: A mini-review and comparison between deep brain stimulation

Magnetic resonance-guided focused ultrasound (MRgFUS) is a new surgical treatment for Parkinson's disease (PD). Previous experience with radiofrequency lesionectomy and deep brain stimulation (DBS) has identified several candidate targets for MRgFUS intended to alleviate the motor symptoms of PD. The main advantage of MRgFUS is that it is incisionless. MRgFUS has certain limitations and is associated with adverse effects. The present study reviews the literature on conventional surgical interventions for PD, discusses recent studies on MRgFUS, and the comparison between DBS and MRgFUS for PD. The reviews aims to provide an essential reference for neurologists to select the appropriate treatments for patients with PD.

Globus Pallidus Internus (GPi) Deep Brain Stimulation for Parkinson's Disease: Expert Review and Commentary

INTRODUCTION

The globus pallidus internus (GPi) region has evolved as a potential target for deep brain stimulation (DBS) in Parkinson's disease (PD). DBS of the GPi (GPi DBS) is an established, safe and effective method for addressing many of the motor symptoms associated with advanced PD. It is important that clinicians fully understand this target when considering GPi DBS for individual patients.

METHODS

The literature on GPi DBS in PD has been comprehensively reviewed, including the anatomy, physiology and potential pitfalls that may be encountered during surgical targeting and post-operative management. Here, we review and address the implications of lead location on GPi DBS outcomes. Additionally, we provide a summary of randomized controlled clinical trials conducted on DBS in PD, together with expert commentary on potential applications of the GPi as target. Finally, we highlight future technologies that will likely impact GPi DBS, including closed-loop adaptive approaches (e.g. sensing-stimulating capabilities), advanced methods for image-based targeting and advances in DBS programming, including directional leads and pulse shaping.

RESULTS

There are important disease characteristics and factors to consider prior to selecting the GPi as the DBS target of PD surgery. Prior to and during implantation of the leads it is critical to consider the neuroanatomy, which can be defined through the combination of image-based targeting and intraoperative microelectrode recording strategies. There is an increasing body of literature on GPi DBS in patients with PD suggesting both short- and long-term benefits. Understanding the GPi target can be useful in choosing between the subthalamic (STN), GPi and ventralis intermedius nucleus as lead locations to address the motor symptoms and complications of PD.

CONCLUSION

GPi DBS can be effectively used in select cases of PD. As the ongoing DBS target debate continues (GPi vs. STN as DBS target), clinicians should keep in mind that GPi DBS has been shown to be an effective treatment strategy for a variety of symptoms, including bradykinesia, rigidity and tremor control. GPi DBS also has an important, direct anti-dyskinetic effect. GPi DBS is easier to program in the outpatient setting and will allow for more flexibility in medication adjustments (e.g. levodopa). Emerging technologies, including GPi closed-loop systems, advanced tractography-based targeting and enhanced programming strategies, will likely be future areas of GPi DBS expansion. We conclude that although the GPi as DBS target may not be appropriate for all PD patients, it has specific clinical advantages.

Ablative brain surgery: an overview

Background: Ablative therapies have been used for the treatment of neurological disorders for many years. They have been used both for creating therapeutic lesions within dysfunctional brain circuits and to destroy intracranial tumors and space-occupying masses. Despite the introduction of new effective drugs and neuromodulative techniques, which became more popular and subsequently caused brain ablation techniques to fall out favor, recent technological advances have led to the resurgence of lesioning with an improved safety profile. Currently, the four main ablative techniques that are used for ablative brain surgery are radiofrequency thermoablation, stereotactic radiosurgery, laser interstitial thermal therapy and magnetic resonance-guided focused ultrasound thermal ablation. Object: To review the physical principles underlying brain ablative therapies and to describe their use for neurological disorders. Methods: The literature regarding the neurosurgical applications of brain ablative therapies has been reviewed. Results: Ablative treatments have been used for several neurological disorders, including movement disorders, psychiatric disorders, chronic pain, drug-resistant epilepsy and brain tumors. Conclusions: There are several ongoing efforts to use novel ablative therapies directed towards the brain. The recent development of techniques that allow for precise targeting, accurate delivery of thermal doses and real-time visualization of induced tissue damage during the procedure have resulted in novel techniques for cerebral ablation such as magnetic resonance-guided focused ultrasound or laser interstitial thermal therapy. However, older techniques such as radiofrequency thermal ablation or stereotactic radiosurgery still have a pivotal role in the management of a variety of neurological disorders.

The role of high-intensity focused ultrasound as a symptomatic treatment for Parkinson's disease

MR-guided focused ultrasound is a novel, minimally invasive surgical procedure for symptomatic treatment of PD. With this technology, the ventral intermediate nucleus, STN, and internal globus pallidus have been targeted for therapeutic cerebral ablation, while also minimizing the risk of hemorrhage and infection from more invasive neurosurgical procedures. In a double-blinded, prospective, sham-controlled randomized controlled trial of MR-guided focused ultrasound thalamotomy for treatment of tremor-dominant PD, 62% of treated patients demonstrated improvement in tremor scores from baseline to 3 months postoperatively, as compared to 22% in the sham group. There has been only one open-label trial of MR-guided focused ultrasound subthalamotomy for patients with PD, demonstrating improvements of 71% for rigidity, 36% for akinesia, and 77% for tremor 6 months after treatment. Among the two open-label trials of MR-guided focused ultrasound pallidotomy for patients with PD, dyskinesia and overall motor scores improved up to 52% and 45% at 6 months postoperatively. Although MR-guided focused ultrasound thalamotomy is now approved by the U.S. Food and Drug Administration for treatment of parkinsonian tremor, additional high-quality randomized controlled trials are warranted and are underway to determine the safety and efficacy of MR-guided focused ultrasound subthalamotomy and pallidotomy for treatment of the cardinal features of PD. These studies will be paramount to aid clinicians to determine the ideal ablative target for individual patients. Additional work will be required to assess the durability of MR-guided focused ultrasound lesions, ideal timing of MR-guided focused ultrasound ablation in the course of PD, and the safety of performing bilateral lesions. © 2019 International Parkinson and Movement Disorder Society.

The origins and persistence of psychosurgery in the state of Iowa

Neurosurgery for the treatment of psychological disorders has a checkered history in the United States. Prior to the advent of antipsychotic medications, individuals with severe mental illness were institutionalized and subjected to extreme therapies in an attempt to palliate their symptoms. Psychiatrist Walter Freeman first introduced psychosurgery, in the form of frontal lobotomy, as an intervention that could offer some hope to those patients in whom all other treatments had failed. Since that time, however, the use of psychosurgery in the United States has waxed and waned significantly, though literature describing its use is relatively sparse. In an effort to contribute to a better understanding of the evolution of psychosurgery, the authors describe the history of psychosurgery in the state of Iowa and particularly at the University of Iowa Department of Neurosurgery. An interesting aspect of psychosurgery at the University of Iowa is that these procedures have been nearly continuously active since Freeman introduced the lobotomy in the 1930s. Frontal lobotomies and transorbital leukotomies were performed by physicians in the state mental health institutions as well as by neurosurgeons at the University of Iowa Hospitals and Clinics (formerly known as the State University of Iowa Hospital). Though the early technique of frontal lobotomy quickly fell out of favor, the use of neurosurgery to treat select cases of intractable mental illness persisted as a collaborative treatment effort between psychiatrists and neurosurgeons at Iowa. Frontal lobotomies gave way to more targeted lesions such as anterior cingulotomies and to neuromodulation through deep brain stimulation. As knowledge of brain circuits and the pathophysiology underlying mental illness continues to grow, surgical intervention for psychiatric pathologies is likely to persist as a viable treatment option for select patients at the University of Iowa and in the larger medical community.

John C. Vangilder (1935-2007): Neurosurgical Leader and Founder of the Department of Neurosurgery at the University of Iowa

John C. VanGilder, the former professor and chairman of neurosurgery at The University of Iowa died on August 27, 2007 after making a lasting impact to the field of neurosurgery both in the United States and abroad. In this manuscript, we review VanGilder's life and achievements. VanGilder was born in 1935 in West Virginia and received his undergraduate education at West Virginia University in Morgantown. He studied medicine at the University of West Virginia, completing his final 2 years at the University of Pittsburgh, and after serving in the U.S. military, completed his neurosurgical training at Washington University in St. Louis. He was appointed to faculty positions first at Yale University and later at The University of Iowa, where he became professor and later chairman of the Division of Neurosurgery. VanGilder also served as president of the Society of Neurological Surgeons (1997-1998), president of the Neurosurgical Society of America (1998-1999), chairman of the American Board of Neurological Surgery (1997-1998), and vice president of the American Academy of Neurological Surgery. At The University of Iowa, VanGilder played a key role in the transition of the Division of Neurosurgery to a Department of Neurosurgery and mentored several neurosurgeons who would go on to become department chairmen or make other important neurosurgical contributions at other medical schools in the United States.