Manbachi, A. | bioRxiv Science

bioRxiv2025

Precision in Spinal Cord Injury Research: A Novel Electromagnetic Impactor for a Consistent Porcine Model

PurposeReplicating spinal cord injury (SCI) in large animals is necessary for evaluating therapeutics for potential human translation, yet there is currently no commercial, standardized device for inducing SCI. We present the fabrication and testing of a custom impactor device for producing repeatable contusion SCI in porcine models. MethodsWe first designed and built the device. Mechanical modeling was subsequently utilized to calibrate our benchtop testing setup. Benchtop verification was performed to measure impact force post calibration. We then used the device to generate a contusion SCI model in 2 pigs and the results were compared to an uninjured pig. Intraoperative ultrasound was used to visualize a hematoma in the injured spinal cord. Hematoxylin-eosin (H&E) and Massons trichrome staining were used to confirm injury presence on ex vivo spinal cord samples. ResultsMechanical modeling forces matched benchtop impact forces within 1.4 N, indicating successful calibration of the testing setup. Our device demonstrated repeatability and the potential for modulating injury severity on the benchtop. Impactor forces were demonstrated across a range from 12.8 to 67.6 N, with variability remaining within 0.2 to 0.7 N standard deviation. The device induced two contusion injuries of different severity in vivo, confirmed by intraoperative ultrasound imaging and post-excision histology of the spinal cord. ConclusionOur impactor device is a major advancement towards producing repeatable and titratable contusions in large animal SCI models.

bioengineering↗

bioRxiv2020

Toward Minimally Invasive Therapeutic Ultrasound: Ultrasound-guided Ablation in Neuro-oncology

IntroductionTo improve patient outcomes (eg, reducing blood loss and infection), practitioners have gravitated toward noninvasive and minimally invasive surgeries (MIS), which demand specialized toolkits. Focused ultrasound, for example, facilitates thermal ablation from a distance, thereby reducing injury to surrounding tissue. Focused ultrasound can often be performed noninvasively; however, it is more difficult to carry out in neuro-oncological tumors, as ultrasound is dramatically attenuated while propagating through the skull. This shortcoming has prompted exploration of MIS options for intracranial placement of focused ultrasound probes, such as within the BrainPath (NICO Corporation, Indianapolis, IN). Herein, we present the design, development, and in vitro testing of an image-guided, focused ultrasound prototype designed for use in MIS procedures. This probe can ablate neuro-oncological lesions despite its small size. Materials & MethodsPreliminary prototypes were iteratively designed, built, and tested. The final prototype consisted of three 8-mm-diameter therapeutic elements guided by an imaging probe. Probe functionality was validated on a series of tissue-mimicking phantoms. ResultsLesions were created in tissue-mimicking phantoms with average dimensions of 2.5x1.2x6.5mm and 3.4x3.25x9.36mm after 10- and 30-second sonification, respectively. 30s sonification with 118W power at 50% duty cycle generated a peak temperature of 68{degrees}C. Each ablation was visualized in real time by the built-in imaging probe. ConclusionWe developed and validated an ultrasound-guided focused ultrasound probe for use in MIS procedures. The dimensional constraints of the prototype were designed to reflect those of BrainPath trocars, which are MIS tools used to create atraumatic access to deep-seated brain pathologies. HIGHLIGHTSO_LIAn ultrasound-guided, focused ultrasound prototype was developed and validated C_LIO_LIThe therapeutic transducer (1.5MHz) consisted of three 8-mm circular elements C_LIO_LIElements were placed on a 9x32mm curved rectangular aperture: 45mm radius curvature C_LIO_LIFunctionality was examined on tissue-mimicking phantoms C_LIO_LI2.5x1.2x6.5mm and 3.4x3.25x9.36mm lesions were seen for 10 and 30s sonification C_LI

bioengineering↗