Potential for thermal damage to the blood–brain barrier during craniotomy: implications for intracortical recording microelectrodes

Shoffstall, Andrew J.; Paiz, Jen E; Miller, David; Rial, Griffin M; Willis, Mitchell; Menendez, Dhariyat M.; Hostler, Stephen R.; Capadona, Jeffrey R.

doi:10.1088/1741-2552/aa9f32

Cited by 48 publications

(36 citation statements)

References 70 publications

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“…Surgery was performed under an operating microscope. Craniotomies were performed carefully with a combination of intermittent pausing and saline application, to prevent overheating from drilling [ 50 ]. A sterile ruler and forceps were used to mark the area to be drilled, 2 mm lateral to midline, 3 mm posterior to bregma (corresponding to a region of the sensory cortex).…”

Section: Methodsmentioning

confidence: 99%

Characterization of the Neuroinflammatory Response to Thiol-ene Shape Memory Polymer Coated Intracortical Microelectrodes

et al. 2018

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Thiol-ene based shape memory polymers (SMPs) have been developed for use as intracortical microelectrode substrates. The unique chemistry provides precise control over the mechanical and thermal glass-transition properties. As a result, SMP substrates are stiff at room temperature, allowing for insertion into the brain without buckling and subsequently soften in response to body temperatures, reducing the mechanical mismatch between device and tissue. Since the surface chemistry of the materials can contribute significantly to the ultimate biocompatibility, as a first step in the characterization of our SMPs, we sought to isolate the biological response to the implanted material surface without regards to the softening mechanics. To accomplish this, we tightly controlled for bulk stiffness by comparing bare silicon ‘dummy’ devices to thickness-matched silicon devices dip-coated with SMP. The neuroinflammatory response was evaluated after devices were implanted in the rat cortex for 2 or 16 weeks. We observed no differences in the markers tested at either time point, except that astrocytic scarring was significantly reduced for the dip-coated implants at 16 weeks. The surface properties of non-softening thiol-ene SMP substrates appeared to be equally-tolerated and just as suitable as silicon for neural implant substrates for applications such as intracortical microelectrodes, laying the groundwork for future softer devices to improve upon the prototype device performance presented here.

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Section: Methodsmentioning

confidence: 99%

Characterization of the Neuroinflammatory Response to Thiol-ene Shape Memory Polymer Coated Intracortical Microelectrodes

et al. 2018

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“…[8][9][10] The use of cooling system has been recognized to reduce bone temperature elevation and remove bone debris. [11][12][13] However, cooling systems could promote infection to the contact surface. 14 Worn drill bits will generate higher bone temperature due to reduce of cutting efficiency.…”

Section: Introductionmentioning

confidence: 99%

Drilling of bone: Effect of drill bit geometries on thermal osteonecrosis risk regions

Akhbar

Yusoff

2018

Proc Inst Mech Eng H

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Bone-drilling operation necessitates an accurate and efficient surgical drill bit to minimize thermal damage to the bone. This article provides a methodology for predicting the bone temperature elevation during surgical bone drilling and to gain a better understanding on the influences of the point angle, helix angle and web thickness of the drill bit. The proposed approach utilized the normalized Cockroft-Latham damage criterion to predict material cracking in the drilling process. Drilling simulation software DEFORM-3D is used to approximate the bone temperature elevation corresponding to different drill bit geometries. To validate the simulation results, bone temperature elevations were evaluated by comparison with ex vivo bone-drilling process using bovine femurs. The computational results fit well with the ex vivo experiments with respect to different drill geometries. All the investigated drill bit geometries significantly affect bone temperature rise. It is discovered that the thermal osteonecrosis risk regions could be reduced with a point angle of 110°to 140°, a helix angle of 5°to 30°and a web thickness of 5% to 40%. The drilling simulation could accurately estimate the maximum bone temperature elevation for various surgical drill bit point angles, web thickness and helix angles. Looking into the future, this work will lead to the research and redesign of the optimum surgical drill bit to minimize thermal insult during bone-drilling surgeries.

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“…Mouse skulls were exposed by a midline incision on the scalp and retraction of the skin using tissue spreaders. Craniotomies were carried out using a 3 mm biopsy punch (PSS select) lateral to midline, and between lambda and bregma, to minimize heat associated with drilling (Shoffstall et al, 2017 ). One alcohol cleaned, ethylene oxide-sterilized silicon probe in the shape of a Michigan-style microelectrode array (2 mm long × 123 μm wide (tapered) × 15 μm thick, 1 mm x 1 mm bond tab) was inserted 2 mm into the craniotomy via forceps to avoid vasculature.…”

Section: Methodsmentioning

confidence: 99%

The Role of Toll-Like Receptor 2 and 4 Innate Immunity Pathways in Intracortical Microelectrode-Induced Neuroinflammation

Hermann

Lin

Soffer

et al. 2018

Front. Bioeng. Biotechnol.

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We have recently demonstrated that partial inhibition of the cluster of differentiation 14 (CD14) innate immunity co-receptor pathway improves the long-term performance of intracortical microelectrodes better than complete inhibition. We hypothesized that partial activation of the CD14 pathway was critical to a neuroprotective response to the injury associated with initial and sustained device implantation. Therefore, here we investigated the role of two innate immunity receptors that closely interact with CD14 in inflammatory activation. We implanted silicon planar non-recording neural probes into knockout mice lacking Toll-like receptor 2 (Tlr2−/−), knockout mice lacking Toll-like receptor 4 (Tlr4−/−), and wildtype (WT) control mice, and evaluated endpoint histology at 2 and 16 weeks after implantation. Tlr4−/− mice exhibited significantly lower BBB permeability at acute and chronic time points, but also demonstrated significantly lower neuronal survival at the chronic time point. Inhibition of the Toll-like receptor 2 (TLR2) pathway had no significant effect compared to control animals. Additionally, when investigating the maturation of the neuroinflammatory response from 2 to 16 weeks, transgenic knockout mice exhibited similar histological trends to WT controls, except that knockout mice did not exhibit changes in microglia and macrophage activation over time. Together, our results indicate that complete genetic removal of Toll-like receptor 4 (TLR4) was detrimental to the integration of intracortical neural probes, while inhibition of TLR2 had no impact within the tests performed in this study. Therefore, approaches focusing on incomplete or acute inhibition of TLR4 may still improve intracortical microelectrode integration and long term recording performance.

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Potential for thermal damage to the blood–brain barrier during craniotomy: implications for intracortical recording microelectrodes

Cited by 48 publications

References 70 publications

Characterization of the Neuroinflammatory Response to Thiol-ene Shape Memory Polymer Coated Intracortical Microelectrodes

Characterization of the Neuroinflammatory Response to Thiol-ene Shape Memory Polymer Coated Intracortical Microelectrodes

Drilling of bone: Effect of drill bit geometries on thermal osteonecrosis risk regions

The Role of Toll-Like Receptor 2 and 4 Innate Immunity Pathways in Intracortical Microelectrode-Induced Neuroinflammation

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