Altered Ulnar Nerve Kinematic Behavior in a Cadaver Model of Entrapment

Mahan, Mark A.; Vaz, Kenneth; Weingarten, David; Brown, Justin M.; Shah, Sameer B.

doi:10.1227/neu.0000000000000705

Cited by 28 publications

(28 citation statements)

References 43 publications

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“…A number of technical challenges remain. Most neural interfaces -even those composed of flexible thin-films like polyimide (here and ref (Hiebl et al, 2010;Lago et al, 2007;Seo et al, 2016)) and parylene (Caravaca et al, 2017;Chamanzar et al, 2015) -present elastic moduli substantially above the kilopascal-range of the host tissues (Mahan et al, 2015;Novak et al, 2012;Patel et al, 1998), aggravating long-term reactive responses and limiting interface longevity. High-resolution 3D printing offers the possibility of orthogonalizing the mechanical and material properties of an object, such that pliable microscale structures can be created from materials that are otherwise stiff and rigid (Bückmann et al, 2012(Bückmann et al, , 2014.…”

Section: Discussionmentioning

confidence: 82%

Printable microscale interfaces for long-term peripheral nerve mapping and precision control

Otchy

Michas

Lee

et al. 2019

Preprint

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The nascent field of bioelectronic medicine seeks to decode and modulate peripheral nervous system signals to obtain therapeutic control of targeted end organs and effectors. Current approaches rely heavily on electrodebased devices, but size scalability, material and microfabrication challenges, limited surgical accessibility, and the biomechanically dynamic implantation environment are significant impediments to developing and deploying advanced peripheral interfacing technologies. Here, we present a microscale implantable device -the nanoclipfor chronic interfacing with fine peripheral nerves in small animal models that begins to meet these constraints.We demonstrate the capability to make stable, high-resolution recordings of behaviorally-linked nerve activity over multi-week timescales. In addition, we show that multi-channel, current-steering-based stimulation can achieve a high degree of functionally-relevant modulatory specificity within the small scale of the device. These results highlight the potential of new microscale design and fabrication techniques for the realization of viable implantable devices for long-term peripheral interfacing.

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Section: Discussionmentioning

confidence: 82%

Printable microscale interfaces for long-term peripheral nerve mapping and precision control

Otchy

Michas

Lee

et al. 2019

Preprint

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“…Previous studies in median and ulnar nerves in rat models and humans revealed higher strains in the joint regions of the nerve, with maximum strains ranging from 20% to 30%. We observed similar distributions and magnitudes of maximum strain in both median and ulnar nerves at the elbow, most prominently in the region just distal to the joint (region D‐J; Fig.…”

Section: Discussionmentioning

confidence: 86%

“…Therefore, nerves must maintain sufficient compliance to maintain their physiological functions . Compounding their biomechanical challenge, nerves undergo especially high epineurial strains—and a corresponding increase in compliance—near joints, as reported in a number of animal and human models . In fact, simple tasks such as elbow flexion can introduce ulnar nerve strains of 10%–15% in the human forearm, but 30% in the elbow .…”

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confidence: 99%

“…9 Compounding their biomechanical challenge, nerves undergo especially high epineurial strains-and a corresponding increase in compliance-near joints, as reported in a number of animal and human models. [10][11][12] In fact, simple tasks such as elbow flexion can introduce ulnar nerve strains of 10%-15% in the human forearm, but 30% in the elbow. 10,13 On the other hand, rabbit tibial nerves and mouse sciatic nerves, seemingly paradoxically, undergo irreversible functional deficits at strains of <15%, 4,14 suggesting considerable variability in the susceptibility to damage of different nerves as well as different regions of the same nerve.…”

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confidence: 99%

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Decoupled epineurial and axonal deformation in mouse median and ulnar nerves

et al. 2019

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Introduction Peripheral nerves accommodate mechanical loads during joint movement. Hypothesized protective features include increased nerve compliance near joints and axonal undulation. How axons perceive nerve deformation is poorly understood. We tested whether nerves increase local axonal undulation in regions of high epineurial strain to protect nerve fibers from strain‐induced damage. Methods Regional epineurial strain was measured near the elbow in median and ulnar nerves of mice expressing axonal fluorescence before and after decompression. Regional axonal tortuosity was quantified under confocal microscopy. Results Nerves showed higher epineurial strain just distal to the medial epicondyle; these differences were eliminated after decompression. Axonal tortuosity also varied regionally; however, unlike in the epineurium, it was greater in proximal regions. Discussion In this study we have proposed a neuromechanical model whereby axons can unravel along their entire length due to looser mechanical coupling to the peri/epineurium. Our findings have major implications for understanding nerve biomechanics and dysfunction. Muscle Nerve 59:619–619, 2019

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“…Interestingly, wrist extension slightly enhanced the classification performance of the CSA (AUC, 0.885), consistent with a trend toward a higher CSA with wrist extension (Table ). This may be a consequence of local nerve tethering at or just distal to the imaging location, which would serve to exaggerate deformation in regions distal to the stretch . Accordingly, control nerves slightly (though not significantly) reduced their CSA with wrist extension, consistent with nerve stretching.…”

Section: Discussionmentioning

confidence: 89%

Assessing the Performance of Morphologic and Echogenic Features in Median Nerve Ultrasound for Carpal Tunnel Syndrome Diagnosis

Byra

Hentzen

et al. 2019

J of Ultrasound Medicine

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Objectives-To assess the feasibility of using ultrasound (US) image features related to the median nerve echogenicity and shape for carpal tunnel syndrome (CTS) diagnosis.Methods-In 31 participants (21 healthy participants and 10 patients with CTS), US images were collected with a 30-MHz transducer from median nerves at the wrist crease in 2 configurations: a neutral position and with wrist extension. Various morphologic features, including the cross-sectional area (CSA), were calculated to assess the nerve shape. Carpal tunnel syndrome commonly results in loss of visualization of the nerve fascicular pattern on US images. To assess this phenomenon, we developed a nerve-tissue contrast index (NTI) method. The NTI is a ratio of average brightness levels of surrounding tissue and the median nerve, both calculated on the basis of a US image. The area under the curve (AUC) from a receiver operating characteristic curve analysis and t test were used to assess the usefulness of the features for differentiation of patients with CTS from control participants.Results-We obtained significant differences in the CSA and NTI parameters between the patients with CTS and control participants (P < .01), with the corresponding highest AUC values equal to 0.885 and 0.938, respectively. For the remaining investigated morphologic features, the AUC values were less than 0.685, and the differences in means between the patients and control participants were not statistically significant (P > .10). The wrist configuration had no impact on differences in average parameter values (P > .09).Conclusions-Patients with CTS can be differentiated from healthy individuals on the basis of the median nerve CSA and echogenicity. Carpal tunnel syndrome is not manifested in a change of the median nerve shape that could be related to circularity or contour variability.

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Altered Ulnar Nerve Kinematic Behavior in a Cadaver Model of Entrapment

Cited by 28 publications

References 43 publications

Printable microscale interfaces for long-term peripheral nerve mapping and precision control

Printable microscale interfaces for long-term peripheral nerve mapping and precision control

Decoupled epineurial and axonal deformation in mouse median and ulnar nerves

Assessing the Performance of Morphologic and Echogenic Features in Median Nerve Ultrasound for Carpal Tunnel Syndrome Diagnosis

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