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Open access

Sushil Patkar

The unilateral submandibular anterior retropharyngeal approach in properly selected patients offers the possibility to expose both atlantoaxial joints adequately, abrade the endplates, and graft the joint spaces. The supine position in extension permits the use of wedge-shaped cages, which reduce the invagination and correct the dislocation. Adequate bone stock is available to rigidly fix the joints using an anterior plate-screw construct without any risk to the vertebral arteries. The approach preserves the posterior tension band and the C2 root. The technique is quick, simple, and safe, and results in solid fusion of the joints over time.

The video can be found here: https://youtu.be/tT6j3Czy6tc

Open access

Miki Katzir, Aboubakr T. Amer, Asad S. Akhter, Stephanus V. Viljoen and Ehud Mendel

The patient is a 69-year-old woman with a history of atlantoaxial instability and cervical pain who underwent an occipital-cervical fusion at an outside hospital. Five days following the procedure she required a PEG tube due to progressive dysphagia. Compared with preoperative imaging, x-ray shows cervical spine hyperextension with a significant decrease in the occipital–C2 angle. A swallow test confirmed aspiration and pharyngeal phase functional impairment. Two-stage surgery consisted of hardware removal, drilling the fused right C1–2 facet, reinstrumentation, and halo placement. The swallowing test confirmed there is no aspiration. We proceeded with rod placement. The patient recovered completely.

The video can be found here: https://youtu.be/YzdJrOm46Y4

Open access

Rajiv R. Iyer and Douglas L. Brockmeyer

This case involved a 6-year-old boy with Down syndrome, left C1 lateral mass hypertrophy, C1–2 rotatory subluxation, and spinal cord compression. He presented after falling down some stairs at his home. Torticollis, dysphagia, and speech delay were noted on examination. Vascular imaging showed impingement on the left vertebral artery by the anomalous C1 lateral mass. Through a posterior approach, the hypertrophic C1 lateral mass was resected, and an occiput–C2 fusion was performed. Postoperatively, his torticollis and brainstem symptoms were resolved.

The video can be found here: https://youtu.be/1U0GLdw6c70

Open access

P. Sarat Chandra and Mohit Agarwal

The author has described his own technique of DCER (distraction, compression, extension, and reduction) to reduce and realign the deformity and relieve spinal compression (indicated in congenital anomalies with occipitalized C1 arch). In addition, he developed special C1–2 spacers and a universal reducer. Here, a 30-year-old male with severe BI (20 mm, above the clivus) with AAD underwent the technique of spacer placement (distraction) followed by cable reduction (leading to compression and extension at the occiput–C1–C2 region). Another short example is presented where an 8-year-old boy (severe BI, AAD with posterior fossa dermoid) underwent additional correction—C2 forward translation and excision of the dermoid.

The video can be found here: https://youtu.be/XIMpkYjxgRk

Free access

J. Blair Price, Aaron E. Rusheen, Abhijeet S. Barath, Juan M. Rojas Cabrera, Hojin Shin, Su-Youne Chang, Christopher J. Kimble, Kevin E. Bennet, Charles D. Blaha, Kendall H. Lee and Yoonbae Oh

The development of closed-loop deep brain stimulation (DBS) systems represents a significant opportunity for innovation in the clinical application of neurostimulation therapies. Despite the highly dynamic nature of neurological diseases, open-loop DBS applications are incapable of modifying parameters in real time to react to fluctuations in disease states. Thus, current practice for the designation of stimulation parameters, such as duration, amplitude, and pulse frequency, is an algorithmic process. Ideal stimulation parameters are highly individualized and must reflect both the specific disease presentation and the unique pathophysiology presented by the individual. Stimulation parameters currently require a lengthy trial-and-error process to achieve the maximal therapeutic effect and can only be modified during clinical visits. The major impediment to the development of automated, adaptive closed-loop systems involves the selection of highly specific disease-related biomarkers to provide feedback for the stimulation platform. This review explores the disease relevance of neurochemical and electrophysiological biomarkers for the development of closed-loop neurostimulation technologies. Electrophysiological biomarkers, such as local field potentials, have been used to monitor disease states. Real-time measurement of neurochemical substances may be similarly useful for disease characterization. Thus, the introduction of measurable neurochemical analytes has significantly expanded biomarker options for feedback-sensitive neuromodulation systems. The potential use of biomarker monitoring to advance neurostimulation approaches for treatment of Parkinson’s disease, essential tremor, epilepsy, Tourette syndrome, obsessive-compulsive disorder, chronic pain, and depression is examined. Further, challenges and advances in the development of closed-loop neurostimulation technology are reviewed, as well as opportunities for next-generation closed-loop platforms.

Free access

Kai J. Miller, Dora Hermes and Nathan P. Staff

Brain–computer interfaces (BCIs) provide a way for the brain to interface directly with a computer. Many different brain signals can be used to control a device, varying in ease of recording, reliability, stability, temporal and spatial resolution, and noise. Electrocorticography (ECoG) electrodes provide a highly reliable signal from the human brain surface, and these signals have been used to decode movements, vision, and speech. ECoG-based BCIs are being developed to provide increased options for treatment and assistive devices for patients who have functional limitations. Decoding ECoG signals in real time provides direct feedback to the patient and can be used to control a cursor on a computer or an exoskeleton. In this review, the authors describe the current state of ECoG-based BCIs that are approaching clinical viability for restoring lost communication and motor function in patients with amyotrophic lateral sclerosis or tetraplegia. These studies provide a proof of principle and the possibility that ECoG-based BCI technology may also be useful in the future for assisting in the cortical rehabilitation of patients who have suffered a stroke.

Open access

Henry Ruiz-Garcia, Kelly Gassie, Lina Marenco-Hillembrand, Angela M. Donaldson and Kaisorn L. Chaichana

Basilar invagination is a challenging dilemma that neurosurgeons may face. Herein, we present a case of a 65-year-old female with a history of rheumatoid arthritis and status post a previous C4–7 ACDF who presented to our clinic with progressive weakness in her bilateral upper and lower extremities. Imaging revealed basilar invagination. She underwent an endoscopic endonasal odontoidectomy followed by an occiput–C6 fusion. We present the endonasal portion of the procedure and have highlighted the technical nuances of this approach. Our goal is to provide better insight into this surgical strategy when dealing with basilar invagination.

The video can be found here: https://youtu.be/aeMbvI_zYQA

Free access

Angad S. Gogia, Roberto Martin Del Campo-Vera, Kuang-Hsuan Chen, Rinu Sebastian, George Nune, Daniel R. Kramer, Morgan B. Lee, Ali R. Tafreshi, Michael F. Barbaro, Charles Y. Liu, Spencer Kellis and Brian Lee

OBJECTIVE

Motor brain-computer interface (BCI) represents a new frontier in neurological surgery that could provide significant benefits for patients living with motor deficits. Both the primary motor cortex and posterior parietal cortex have successfully been used as a neural source for human motor BCI, leading to interest in exploring other brain areas involved in motor control. The amygdala is one area that has been shown to have functional connectivity to the motor system; however, its role in movement execution is not well studied. Gamma oscillations (30–200 Hz) are known to be prokinetic in the human cortex, but their role is poorly understood in subcortical structures. Here, the authors use direct electrophysiological recordings and the classic “center-out” direct-reach experiment to study amygdaloid gamma-band modulation in 8 patients with medically refractory epilepsy.

METHODS

The study population consisted of 8 epilepsy patients (2 men; age range 21–62 years) who underwent implantation of micro-macro depth electrodes for seizure localization and EEG monitoring. Data from the macro contacts sampled at 2000 Hz were used for analysis. The classic center-out direct-reach experiment was used, which consists of an intertrial interval phase, a fixation phase, and a response phase. The authors assessed the statistical significance of neural modulation by inspecting for nonoverlapping areas in the 95% confidence intervals of spectral power for the response and fixation phases.

RESULTS

In 5 of the 8 patients, power spectral analysis showed a statistically significant increase in power within regions of the gamma band during the response phase compared with the fixation phase. In these 5 patients, the 95% bootstrapped confidence intervals of trial-averaged power in contiguous frequencies of the gamma band during the response phase were above, and did not overlap with, the confidence intervals of trial-averaged power during the fixation phase.

CONCLUSIONS

To the authors’ knowledge, this is the first time that direct neural recordings have been used to show gamma-band modulation in the human amygdala during the execution of voluntary movement. This work indicates that gamma-band modulation in the amygdala could be a contributing source of neural signals for use in a motor BCI system.

Free access

Yuhan Wang, Chencheng Zhang, Yingying Zhang, Hengfen Gong, Jun Li, Haiyan Jin, Dianyou Li, Dengtang Liu and Bomin Sun

Schizophrenia is a psychiatric disorder associated with significant morbidity and mortality. Although antipsychotic medications and electroconvulsive therapy can be used to manage the clinical symptoms of schizophrenia, a substantial portion (10%–30%) of patients do not clinically respond to these treatments or cannot tolerate the side effects. Recently, deep brain stimulation (DBS) has emerged as a promising safe and effective therapeutic intervention for various psychiatric disorders. Here, the authors explore the utility of DBS of the habenula (HB) in the clinical management of 2 young adult male patients with severe, chronic, and treatment-resistant schizophrenia. After HB DBS surgery, both patients experienced improvements in clinical symptoms during the first 6 months of treatment. However, only 1 patient retained the clinical benefits and reached a favorable outcome at 12-month follow-up. The symptoms of the other patient subsequently worsened and became so profound that he needed to be hospitalized at 10-month follow-up and withdrawn from further study participation. It is tentatively concluded that HB DBS could ultimately be a relatively safe and effective surgical intervention for certain patients with treatment-resistant schizophrenia.