Neurosurgical focus最新文献

Complications from spine surgery are not just devastating because they happen, or because we believe that complications can be avoided, but are magnified because many of the complications occur in elective cases. Catastrophic outcomes in surgeries that are intended to improve lifestyle and comfort do not fit our sensibility. In the first Neurosurgical Focus issue on complications published in October 2024, most of the complications shared involved cranial neurosurgery. Many of these complications occurred in cases in which there was no acceptable option except to operate, such as cases involving extensive arteriovenous malformations, tumors, and aneurysms. In life-threatening diseases, the existence of challenged outcomes is often considered the trade-off. In spine surgery, however, we face risks of worse functional outcomes in patients who often have other options. We roll stochastic dice with each surgery. A 2% risk of a certain complication occurs with random precision and strikes with 100% completeness. This makes complications in spine surgery hard to express to patients in their full reality, hard to process for the surgeon when they do occur, and sometimes hard to bring to light, because the presence of a serious complication in an elective case horrifies. This issue of Neurosurgical Focus, like the laudable issue before, attempts to grapple with these challenges by presenting spinal complications in all of their attendant difficulties. These case illustrations were all written by esteemed and senior neurosurgeons who share hundreds of years of experience among them. The authors have a track record of sound judgment and technical excellence but are laying bare the challenges they have faced, primarily because they recognize the benefits of awareness and of the personal lessons they learned. A layer of anonymity is created by disassociating individual work from the authors. Videos were narrated by an individual who was not involved in video or case preparation.

Objective: The long-term goal of this work is to develop a sensorimotor brain-machine interface (BMI) in which intended movements are decoded from the motor cortex and proprioceptive feedback is delivered via intracortical microstimulation of Brodmann's area 3a. A vital step toward this goal is to demonstrate in rhesus macaques a novel surgical approach for the precise and safe implantation of custom-length microelectrode arrays into area 3a at the bottom of the central sulcus.

Methods: Preoperative planning combined high-resolution 7-T MR and CT imaging to generate 3D models of the cortices of 2 subjects. These models were used to fabricate 3D-printed skull replicas and to define a stereotactic trajectory that provided the shortest perpendicular path to the base of the central sulcus, where Brodmann's area 3a resides. Custom variable-length microwire electrode arrays were designed to span this target region. The flexibility of the microwires precluded the standard impact-insertion approach used with stiffer electrodes. Therefore, a custom vacuum-powered microdrive holder that moved with the pulsating brain was developed to maintain electrode orientation and to allow slow, controlled insertion along the planned trajectory. After implantation, the craniotomy was closed, and a skull-mounted recording chamber was secured. Postoperative verification of array placement was performed using CT imaging and neural recordings.

Results: In both animals, imaging revealed that the base of the central sulcus was positioned anterior to its dorsal opening, making a precentral implant trajectory the shortest and most direct path to the bottom of the central sulcus. The integrated imaging and 3D modeling approach enabled accurate stereotactic placement of custom microelectrode arrays using the novel vacuum-assisted microdrive, as confirmed by postoperative CT imaging. Both surgical procedures were completed without complication, and isolatable neuronal spikes were recorded from multiple channels in each subject. In both animals, neural activity was modulated by passive movements of the arm.

Conclusions: Intracortical microelectrode implants for BMI applications have traditionally been limited to short (1.5-mm) electrodes targeting cortical sites exposed on the brain surface. The surgical methodology described here enables safe and accurate implantation of custom-length arrays into deep sulcal targets such as Brodmann's area 3a. By expanding access to previously inaccessible cortical regions, this approach broadens the potential neural information available for future BMI applications.

Objective: The aim of this study was to evaluate the feasibility of using the Layer 7 Cortical Interface, a high-density micro-electrocorticography (μECoG) array, for intraoperative neural recordings and real-time brain-computer interface (BCI) applications, including speech decoding and cursor control.

Methods: Four patients (age range 23-43 years) who underwent awake craniotomy for tumor resection near the eloquent cortex were enrolled. The Layer 7 µECoG device (1024 channels, approximately 1.5-cm2 coverage) was placed on the motor cortex following standard cortical mapping. Intraoperative tasks included a joystick-controlled center-out movement paradigm (n = 3) and an auditory-cued speech repetition task (n = 1). Neural data were recorded at 20 kHz, preprocessed, and used to train decoders intraoperatively. A transformer-based model was applied for real-time speech synthesis and a convolutional neural network was trained for speech classification, while a convolutional recurrent neural network was trained to classify 2D cursor direction.

Results: All 4 patients tolerated the procedure without device-related adverse events. The mean electrode impedances across 6 arrays (6144 channels) ranged from 1.21 to 1.99 MΩ, with 954-990 channels per array retained for analysis. In the speech task, a 4-word classification model achieved 77.5% accuracy, and a real-time synthesis model was able to distinguish speech and silence during approximately 20 minutes of data recording in the operating room. In the motor task, a 4-direction classification model achieved 78%-84% accuracy. Recordings remained stable during tumor resection.

Conclusions: The Layer 7 Cortical Interface device enabled high-resolution nonpenetrating cortical recordings that supported real-time speech classification and cursor control within the limited timeframe of an intraoperative session. These findings highlight the potential clinical applications of high-density µECoG for functional mapping, diagnostic assessment, and future chronic BCI systems for patients with motor and communication impairments.

Acute and chronic CNS pathologies that result in tissue loss remain among the most intractable problems in neurosurgery, with current treatments focused on stabilization and neuroprotection rather than structural repair. Neural interfaces such as recording, stimulating, or replacing neural activity have demonstrated value in restoring function via prostheses and brain-computer interfaces, yet these approaches are constrained by electrode design, bandwidth, and limited biological integration. Engineered neuroglial organoids offer a complementary, biologically based interface strategy. Derived from pluripotent stem cells, neuroglial organoids arrive as 3D constructs containing neurons and glia in intrinsic architecture, capable of vascularization, synaptic connectivity, and integration with host tissue. Building on dissociated stem cell suspensions, organoids act not only as reservoirs of cells but also as living neural interfaces, receiving inputs from host circuits and generating functional outputs. Preclinical studies have demonstrated that transplanted organoids can couple to host sensory pathways, respond to stimulation, and support recovery of motor and cognitive functions. Moreover, emerging work coupling organoid grafts to brain-computer interfaces highlights the potential for closed-loop biological electronic systems, in which engineered devices provide precise recording and stimulation while organoids contribute adaptive, active biological circuits. This combination allows real-time bidirectional communication, allowing the graft to be both monitored and adapted to structurally and functionally integrate into host tissue. In this review, the authors examine neuroglial organoid transplantation through the lens of neural interfacing. They outline lessons from non-CNS organoid transplantation, summarize neurotrauma studies where grafts engage host circuits, and highlight opportunities to integrate organoids with electrodes, stimulation paradigms, and computational models. They also discuss challenges, namely vascularization, immune tolerance, surgical delivery, and manufacturing standards, that parallel those in neural device translation. For neurosurgeons, the appeal of neuroglial organoids lies not only in tissue replacement but in establishing a new class of biological neural interfaces, extending the reach of restorative neurosurgery. By merging living constructs with engineered devices, organoid-based strategies may enable hybrid restorative systems that restore function after neurological injury and disease.