Online speech synthesis using a chronically implanted brain-computer interface in an individual with ALS.

Brain-computer interfaces (BCIs) that reconstruct and synthesize speech using brain activity recorded with intracranial electrodes may pave the way toward novel communication interfaces for people who have lost their ability to speak, or who are at high risk of losing this ability, due to neurological disorders. Here, we report online synthesis of intelligible words using a chronically implanted brain-computer interface (BCI) in a man with impaired articulation due to ALS, participating in a clinical trial (ClinicalTrials.gov, NCT03567213) exploring different strategies for BCI communication. The 3-stage approach reported here relies on recurrent neural networks to identify, decode and synthesize speech from electrocorticographic (ECoG) signals acquired across motor, premotor and somatosensory cortices. We demonstrate a reliable BCI that synthesizes commands freely chosen and spoken by the participant from a vocabulary of 6 keywords previously used for decoding commands to control a communication board. Evaluation of the intelligibility of the synthesized speech indicates that 80% of the words can be correctly recognized by human listeners. Our results show that a speech-impaired individual with ALS can use a chronically implanted BCI to reliably produce synthesized words while preserving the participant's voice profile, and provide further evidence for the stability of ECoG for speech-based BCIs.

The Shunt Valve Recession Technique as a Neuroplastic Surgery Adjunct in Complex and High-Risk Shunt Revisions: Technical Note and Case Series.

BACKGROUND AND OBJECTIVES: Ventricular shunting is one of the most common procedures in neurosurgery. However, complications and revisions are frequent. Patients requiring multiple revisions often suffer secondary issues with scalp healing over hardware. Many common ventricular shunt valves have an obligate thickness that creates a visible protrusion and can potentially cause local tissue ischemia and breakdown in the setting of repeated surgery. The authors present a simple technique for recessing the shunt valve into the underlying bone to alleviate protrusion in high-risk cases. Three example cases utilizing this technique are presented. METHODS: The skull directly underlying the planned valve site is uniformly recessed with a cutting burr several millimeters as desired while maintaining the inner cortical bone layer. The valve is fixed with standard cranial plating hardware. EXPECTED OUTCOMES: Three patients are reported who underwent shunt valve recession as an adjunct to their shunt revision with neuroplastic surgery assistance. All patients had undergone multiple prior surgeries that had resulted in thin and high-risk fragile scalp. In 1 patient, the prior valve was eroding through the scalp before the described revision. All patients had satisfactory cosmetic outcomes, and there were no revisions in the 2-month follow-up period. DISCUSSION: Complex and high-risk ventricular shunt patients should be considered for shunt valve recession into the bone to reduce wound-related complications and enhance healing. This is a technically simple, safe, and effective technique to include as a neuroplastic adjunct.

Skull and Scalp En-Bloc Harvest Protects Calvarial Perfusion: A Cadaveric Study.

BACKGROUND: Calvarial defects are severe injuries that can result from a wide array of etiologies. Reconstructive modalities for these clinical challenges include autologous bone grafting or cranioplasty with biocompatible alloplastic materials. Unfortunately, both approaches are limited by factors such as donor site morbidly, tissue availability, and infection. Calvarial transplantation offers the potential opportunity to address skull defect form and functional needs by replacing "like-with-like" tissue but remains poorly investigated. METHODS: Three adult human cadavers underwent circumferential dissection and osteotomy to raise the entire scalp and skull en-bloc. The vascular pedicles of the scalp were assessed for patency and perfused with color dye, iohexol contrast agent for computed tomography (CT) angiography, and indocyanine green for SPY-Portable Handheld Imager assessment of perfusion to the skull. RESULTS: Gross changes were appreciated to the scalp with color dye, but not to bone. CT angiography and SPY-Portable Handheld Imager assessment confirmed perfusion from the vessels of the scalp to the skull beyond midline. CONCLUSION: Calvarial transplantation may be a technically viable option for skull defect reconstruction that requires vascularized composite tissues (bone and soft tissue) for optimal outcomes.

Online speech synthesis using a chronically implanted brain-computer interface in an individual with ALS.

Recent studies have shown that speech can be reconstructed and synthesized using only brain activity recorded with intracranial electrodes, but until now this has only been done using retrospective analyses of recordings from able-bodied patients temporarily implanted with electrodes for epilepsy surgery. Here, we report online synthesis of intelligible words using a chronically implanted brain-computer interface (BCI) in a clinical trial participant (ClinicalTrials.gov, NCT03567213) with dysarthria due to amyotrophic lateral sclerosis (ALS). We demonstrate a reliable BCI that synthesizes commands freely chosen and spoken by the user from a vocabulary of 6 keywords originally designed to allow intuitive selection of items on a communication board. Our results show for the first time that a speech-impaired individual with ALS can use a chronically implanted BCI to reliably produce synthesized words that are intelligible to human listeners while preserving the participants voice profile.

Skull and Scalp En-Bloc Harvest Protects Calvarial Perfusion: A Cadaveric Study.

BACKGROUND: Calvarial defects are severe injuries that can result from a wide array of etiologies. Reconstructive modalities for these clinical challenges include autologous bone grafting or cranioplasty with biocompatible alloplastic materials. Unfortunately, both approaches are limited by factors such as donor site morbidly, tissue availability, and infection. Calvarial transplantation offers the potential opportunity to address skull defect form and functional needs by replacing "like-with-like" tissue but remains poorly investigated. METHODS: Three adult human cadavers underwent circumferential dissection and osteotomy to raise the entire scalp and skull en-bloc. The vascular pedicles of the scalp were assessed for patency and perfused with color dye, iohexol contrast agent for computed tomography (CT) angiography, and indocyanine green for SPY-Portable Handheld Imager assessment of perfusion to the skull. RESULTS: Gross changes were appreciated to the scalp with color dye, but not to bone. CT angiography and SPY-Portable Handheld Imager assessment confirmed perfusion from the vessels of the scalp to the skull beyond midline. DISCUSSION/CONCLUSION: Calvarial transplantation may be a technically viable option for skull defect reconstruction that requires vascularized composite tissues (bone and soft tissue) for optimal outcomes.

First Experience With Postoperative Transcranial Ultrasound Through Sonolucent Burr Hole Covers in Adult Hydrocephalus Patients.

BACKGROUND: Managing patients with hydrocephalus and cerebrospinal fluid (CSF) disorders requires repeated head imaging. In adults, it is typically computed tomography (CT) or less commonly magnetic resonance imaging (MRI). However, CT poses cumulative radiation risks and MRI is costly. Ultrasound is a radiation-free, relatively inexpensive, and optionally point-of-care alternative, but is prohibited by very limited windows through an intact skull. OBJECTIVE: To describe our initial experience with transcutaneous transcranial ultrasound through sonolucent burr hole covers in postoperative hydrocephalus and CSF disorder patients. METHODS: Using cohort study design, infection and revision rates were compared between patients who underwent sonolucent burr hole cover placement during new ventriculoperitoneal shunt placement and endoscopic third ventriculostomy over the 1-year study time period and controls from the period 1 year before. Postoperatively, trans-burr hole ultrasound was performed in the clinic, at bedside inpatient, and in the radiology suite to assess ventricular anatomy. RESULTS: Thirty-seven patients with sonolucent burr hole cover were compared with 57 historical control patients. There was no statistically significant difference in infection rates between the sonolucent burr hole cover group (1/37, 2.7%) and the control group (0/57, P = .394). Revision rates were 13.5% vs 15.8% (P = 1.000), but no revisions were related to the burr hole or cranial hardware. CONCLUSION: Trans-burr hole ultrasound is feasible for gross evaluation of ventricular caliber postoperatively in patients with sonolucent burr hole covers. There was no increase in infection rate or revision rate. This imaging technique may serve as an alternative to CT and MRI in the management of select patients with hydrocephalus and CSF disorders.

Discussion on: "Let's Smarten Up: Smart Devices and the Internet of Things, an Untapped Resource for Innovation in Craniofacial Surgery".

Prior to Dr. Paul Tessier's teachings in the 1960's, many neurosurgeons and craniofacial surgeons took shortcuts and employed alloplastic materials fraught with complication, and soon thereafter, both surgical specialties moved the pendulum towards the side of bone grafts being the gold standard for neurosurgical reconstruction and the art of cranioplasty. But now half a century later, neuroplastic surgery is moving the pendulum the other way. Without a doubt, the brain is a critical organ that needs some form of modulation as opposed to replacement. The intervention delivered can be in the form of electricity, light, medicine, etc. Regardless of the medium, it needs to be housed somewhere. And there is no better real estate than to be housed within a sterile alloplastic case with embedded smart technologies; in a way that prevents obvious, visual deformity. For example, it would be naïve to think that the future of embedded neurotechnologies will one day be housed safely and dependably within one's own bone flap. Hence, moving forward, time-tested alloplastic materials will become the new gold standard for cranioplasty reconstruction as the world starts to welcome a generation of smart cranial devices; some of which may house Bluetooth-connected, Wifi-enabled, MRI-compatible pumps to perform convection-enhanced delivery of time-tested medicines - thereby forever changing the way we approach chronic neurological disease and the forever-obstructing, blood-brain barrier. As this happens, I feel confident saying that both Tessier and Cushing are somewhere applauding and smiling on these efforts.

Special Considerations in Face Transplantation: A Systematic Review.

ABSTRACT: Vascularized composite allotransplantation of the face is an exceedingly complex procedure, requiring extensive planning and surgical precision in order to successfully manage patients with facial disfigurements. This review aims to present an overview of the salient anatomic considerations in facial transplantation, as well as give attention to unique patient populations and special considerations.A literature review was performed in search of articles pertaining to considerations in facial transplantation using the databases PubMed, Web of Science, and Cochrane. Articles selected for further review included full-text articles with an emphasis on specific anatomic defects and how they were addressed in the transplant process, as well as management of special patient populations undergoing facial transplantation. In total, 19 articles were deemed appropriate for inclusion.The use of computer-assisted technologies for the planning portion of the procedure, as well as intraoperative efficiency, has yielded favorable results and can be considered as part of the operative plan. The ultimate outcome is dependent upon the synchronization of subunits of the allograft and the desired functional outcomes, including osseous, ocular, oral, and otologic considerations. Management of specific pathology and subgroups of patients are critical aspects. Although pediatric face transplantation has not yet been performed, it is a likely a future step in the evolution of this procedure.When performing a face transplantation, many components must be considered pre-, intra-, and post-operatively. This systematic review presents specific anatomic considerations, as well as information about special patient populations within this crosssection of multidisciplinary microsurgery, psychiatry, and transplant immunology.

Cranioplasty Outcomes From 500 Consecutive Neuroplastic Surgery Patients.

BACKGROUND: Cranioplasty is critical to cerebral protection and restoring intracranial physiology, yet this procedure is fraught with a high risk of complications. The field of neuroplastic surgery was created to improve skull and scalp reconstruction outcomes in adult neurosurgical patients, with the hypothesis that a multidisciplinary team approach could help decrease complications. OBJECTIVE: To determine outcomes from a cohort of cranioplasty surgeries performed by a neuroplastic surgery team using a consistent surgical technique and approach. METHODS: The authors reviewed 500 consecutive adult neuroplastic surgery cranioplasties that were performed between January 2012 and September 2020. Data were abstracted from a prospectively maintained database. Univariate analysis was performed to determine association between demographic, medical, and surgical factors and odds of revision surgery. RESULTS: Patients were followed for an average of 24 months. Overall, there was a reoperation rate of 15.2% (n = 76), with the most frequent complications being infection (7.8%, n = 39), epidural hematoma (2.2%, n = 11), and wound dehiscence (1.8%, n = 9). New onset seizures occurred in 6 (1.2%) patients.Several variables were associated with increased odds of revision surgery, including lower body mass ratio, 2 or more cranial surgeries, presence of hydrocephalus shunts, scalp tissue defects, large-sized skull defect, and autologous bone flaps. importantly, implants with embedded neurotechnology were not associated with increased odds of reoperation. CONCLUSIONS: These results allow for comparison of multiple factors that impact risk of complications after cranioplasty and lay the foundation for development of a cranioplasty risk stratification scheme. Further research in neuroplastic surgery is warranted to examine how designated centers concentrating on adult neuro-cranial reconstruction and multidisciplinary collaboration may lead to improved cranioplasty outcomes and decreased risks of complications in neurosurgical patients.

Cranioplasty With Customized Craniofacial Implants and Intraoperative Resizing for Single-Stage Reconstruction Following Oncologic Resection of Skull Neoplasms.

BACKGROUND: Craniectomies requiring skull reconstruction are indicated following oncological resection of masses involving the underlying brain and/or skull. Immediate cranioplasties have previously been performed using suboptimal hand-bending or molding techniques using "off - the - shelf" products. Today with computer - aided design, customized craniofacial implants have become widely available for personalized reconstruction of resected bone and soft tissue. We present here the largest series to date of single stage reconstruction using alloplastic biomaterials in consecutive patient series with oversized customized implants. METHODS: A single-surgeon, retrospective, 8-year study was conducted on all consecutive patients undergoing single stage cranioplasty with prefabricated implants using a myriad of biomaterials. All outcomes were analyzed in detail and compared with previous studies utilizing similar alloplastic implants. RESULTS: In total, 56 patients underwent resection of skull neoplasms and subsequent cranioplasty reconstruction using customized implants. The most common neoplasms were meningiomas (39%). The most common complications seen among patients were dehiscence - (7%), and extrusion of implant - (3.5%). There was no significant difference in the incidence of postoperative complications between patients who had postoperative chemotherapy/radiotherapy versus those that did not (22.2% versus 13.1%, P = 0.39). One-year follow-up revealed acceptable cranial contour and symmetry in all 56 cases. CONCLUSIONS: This is a consecutive case series of prefabricated single-stage cranioplasty, following resection of brain tumors with bone extension or skull bone neoplasm, demonstrating excellent results with regards to safety and patient satisfaction. There are several advantages such as comprehensive resection and reconstruction plan using 3D models, shorter operative time, and better restoration of complex anatomy.

Automated Implant Resizing for Single-Stage Cranioplasty.

Patient-specific customized cranial implants (CCIs) are designed to fill the bony voids in the cranial and craniofacial skeleton. The current clinical approach during single-stage cranioplasty involves a surgeon modifying an oversized CCI to fit a patient's skull defect. The manual process, however, can be imprecise and time-consuming. This paper presents an automated surgical workflow with a robotic workstation for intraoperative CCI modification that provides higher resizing accuracy compared to the manual approach. We proposed a 2-scan method for intraoperative patient-to-CT registration using reattachable fiducial markers to address the registration issue caused by the clinical draping requirement. First, the draped defected skull was 3D scanned and registered to the CT space using our proposed 2-scan registration method. Next, our algorithm generates a robot cutting toolpath based on the 3D defect model. The robot then performs automatic 3D scanning to localize the implant and resizes the implant to match the cranial defect. We evaluated the implant resizing accuracy of the proposed paradigm against the resizing accuracy of the manual approach by an expert surgeon on two plastic skulls and two cadavers. The evaluation results showed that our system was able to decrease the bone gap distance by more than 60% and 30% on plastic skulls and cadavers respectively compared to the manual approach, indicating lower risk of post-surgical complication and better aesthetic restoration.

The Impact of Hydrocephalus Shunt Devices on Quality of Life.

BACKGROUND: Despite advances in hydrocephalus shunt technology and improvement in hydrocephalus management, many patients have chronic disability and require multiple surgeries throughout their lifetime. There is limited data from patients' perspective regarding the impact of shunt devices on quality-of-life. METHODS: A cross-sectional survey was developed to evaluate the impact of shunt devices on patient quality-of-life. The survey was distributed via social media platforms of the Hydrocephalus Association, and patients self-selected to anonymously complete the online questionnaire. A literature review was performed to contextualize the findings from the survey. RESULTS: A total of 562 survey responses were obtained from a network encompassing 35,000 members. The mean age was 30 years old (0.5-87), and 65% identified as female. Eighty one percent underwent at least 1 shunt revision surgery, with a reported average of 10 shunt revision surgeries per patient (1-200 surgeries). Occlusion, shunt migration and infection were the leading causes for revision at 60%, 47%, and 35%, respectively. In addition, 72% of patients reported pain and discomfort from the device, and 68% expressed avoidance of certain activities due to "fear of bumping shunt." Despite numerous articles discussing shunt technology, a review of the literature indicated a paucity of studies specifically evaluating the burden of shunt devices from a patient/caregiver perspective. CONCLUSIONS: The findings from this study suggest long-term physical and psychosocial burden associated with shunt devices. Importantly, this study highlights the need for concerted efforts to develop validated tools to study patient reported outcomes as it relates to neurocranial implanted devices.

Novel intraoperative online functional mapping of somatosensory finger representations for targeted stimulating electrode placement: technical note.

Defining eloquent cortex intraoperatively, traditionally performed by neurosurgeons to preserve patient function, can now help target electrode implantation for restoring function. Brain-machine interfaces (BMIs) have the potential to restore upper-limb motor control to paralyzed patients but require accurate placement of recording and stimulating electrodes to enable functional control of a prosthetic limb. Beyond motor decoding from recording arrays, precise placement of stimulating electrodes in cortical areas associated with finger and fingertip sensations allows for the delivery of sensory feedback that could improve dexterous control of prosthetic hands. In this study, the authors demonstrated the use of a novel intraoperative online functional mapping (OFM) technique with high-density electrocorticography to localize finger representations in human primary somatosensory cortex. In conjunction with traditional pre- and intraoperative targeting approaches, this technique enabled accurate implantation of stimulating microelectrodes, which was confirmed by postimplantation intracortical stimulation of finger and fingertip sensations. This work demonstrates the utility of intraoperative OFM and will inform future studies of closed-loop BMIs in humans.

Translucent Customized Cranial Implants Made of Clear Polymethylmethacrylate: An Early Outcome Analysis of 55 Consecutive Cranioplasty Cases.

BACKGROUND: Large skull reconstruction, with the use of customized cranial implants, restores cerebral protection, physiologic homeostasis, and one's preoperative appearance. Cranial implants may be composed of either bone or a myriad of alloplastic biomaterials. Recently, patient-specific cranial implants have been fabricated using clear polymethylmethacrylate (PMMA), a visually transparent and sonolucent variant of standard opaque PMMA. Given the new enhanced diagnostic and therapeutic applications of clear PMMA, we present here a study evaluating all outcomes and complications in a consecutive patient series. METHODS: A single-surgeon, retrospective, 3-year study was conducted on all consecutive patients undergoing large cranioplasty with clear PMMA implants (2016-2019). Patients who received clear PMMA implants with embedded neurotechnologies were excluded due to confounding variables. All outcomes were analyzed in detail and compared with previous studies utilizing similar alloplastic implant materials. RESULTS: Fifty-five patients underwent cranioplasty with customized clear PMMA implants. Twenty-one (38%) were performed using a single-stage cranioplasty method (ie, craniectomy and cranioplasty performed during the same operation utilizing a prefabricated, oversized design and labor-intense, manual modification), whereas the remaining 34 (62%) underwent a standard, 2-stage reconstruction (craniectomy with a delayed surgery for cranioplasty and minimal-to-no implant modification necessary). The mean cranial defect size was 101.8 cm. The mean follow-up time was 9 months (range, 1.5-39). Major complications requiring additional surgery occurred in 7 patients (13%) consisting of 2 (4%) cerebrospinal fluid leaks, 2 (4%) epidural hematomas, and 3 (4%) infections. In addition, 3 patients developed self-limiting or nonoperative complications including 2 (4%) with new onset seizures and 1 (2%) with delayed scalp healing. CONCLUSIONS: This is the first reported consecutive case series of cranioplasty reconstruction using customized clear PMMA implants, demonstrating excellent results with regard to ease of use, safety, and complication rates well below published rates when compared with other alloplastic materials. Clear PMMA also provides additional benefits, such as visual transparency and sonolucency, which is material specific and unavailable with autologous bone. Although these early results are promising, further studies with multicenter investigations are well justified to evaluate long-term outcomes.

Investigation of a Valve-Agnostic Cranial Implant for Adult Hydrocephalus Patients Requiring Ventriculoperitoneal Shunting.

INTRODUCTION: Currently, the most effective treatment strategy for adults with hydrocephalus involves cerebrospinal fluid diversion by means of a shunt system, most commonly ventriculoperitoneal shunts (VPS). Ventriculoperitoneal shunting is associated with high complication and/or revision rates, in part due to the high-profile programmable valve designs. Thus, the valve-agnostic cranial implant (VACI) was designed and investigated as a safe and effective method of reducing the valve's high profile and is currently undergoing clinical trials. As such, the objective of this study was to collate preliminary, multi-institutional data of early outcomes using a VACI approach for patients requiring VPS by way of an Institutional Review Board approved registry. METHODS: A total of 25 adult patients across 4 institutions and 6 surgeons underwent VACI placement for VPS based on preoperative evaluation and perceived benefit. Patient demographics, operative details, and preliminary outcomes are presented here. RESULTS: Valve-agnostic cranial implant placement via a limited size craniectomy at time of shunt revision was performed with no adverse events. Over an average follow-up period of 1 year (394 ±â€Š178 days), 92% of patients experienced no major shunt-related or scalp-related complications. There were 2 cases with a major complication requiring reoperation: 1 shunt tubing extrusion and 1 case of meningitis. The most frequent postsurgical intervention seen in this study was related to adjustment of drainage: a non-invasively performed valve reprogramming after initial shunt placement when proper flow rate is being established. Of the 8 cases of drainage adjustment, all but 1 (88%) were receiving a VPS for the first time, with the exception undergoing a fourth shunt revision. All instances of improper flow were treated non-surgically and remediated effectively via shunt reprogramming in clinic. Removal of the VACI was not indicated in any treatment course. In this way, all complications as they relate to the shunt valve were minor and required nonsurgical intervention, and no complications reported were directly or indirectly caused by using the VACI. CONCLUSION: Preliminary findings from this multicenter trial suggest promising outcomes with a low complication rate for patients with hydrocephalus undergoing VACI placement during VPS. Ongoing research will continue to provide a more robust clinical picture of VACI in hydrocephalus management as more data becomes available.