The advent of genetically encoded calcium indicators, along with surgical preparations such as thinned skulls or refractive index matched skulls, have enabled mesoscale cortical activity imaging in head-fixed mice. However, neural activity during unrestrained behavior substantially differs from neural activity in head-fixed animals. For whole-cortex imaging in freely behaving mice, we here present the “mini-mScope,” a wide-field, miniaturized, and head-mounted fluorescence microscope compatible with transparent polymer skull preparations. With a field of view of 8 mm x 10 mm and weighing less than 4 g, the mini-mScope can image most of the mouse dorsal cortex with resolution ranging from 39 to 56 μm. We have used the mini-mScope to record mesoscale calcium activity across the dorsal cortex during sensory-evoked stimuli, open field behaviors, social interactions, and transitions from wakefulness to sleep.

Over the last few decades, a plethora of tools has been developed for neuroscientists to interface with the brain. Implementing these tools requires precisely removing sections of the skull to access the brain. These delicate cranial microsurgical procedures need to be performed on the sub-millimeter thick bone without damaging the underlying tissue and therefore, require significant training. Automating some of these procedures would not only enable more precise microsurgical operations, but also facilitate widespread use of advanced neurotechnologies. Here, we introduce the “Craniobot”, a cranial microsurgery platform that combines automated skull surface profiling with a computer numerical controlled (CNC) milling machine to perform a variety of cranial microsurgical procedures on mice. The Craniobot utilizes a low-force contact sensor to profile the skull surface and uses this information to perform precise milling operations within minutes. We have used the Craniobot to perform intact skull thinning and open small to large craniotomies over the dorsal cortex.

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Over the last decade, a plethora of tools have been developed for neuroscientists to interface with the brain. Implementing these tools requires precise removal of sections of the skull to access the brain. These delicate cranial microsurgical procedures need to be performed on sub-millimeter thick bone without damaging the underlying tissue and therefore, require significant training. Automating some of these procedures would not only enable more precise microsurgical operations, but also democratize use of advanced neurotechnologies. Here, we describe the 'Craniobot', a cranial microsurgery platform that combines automated skull surface profiling with a computer numerical controlled (CNC) milling machine to perform a variety of cranial microsurgical procedures in mice. The Craniobot utilizes a low force contact sensor to profile the skull surface and uses this information to perform micrometer-scale precise milling operations within minutes. We have used the Craniobot to drill pilot holes to anchor cranial implants, perform skull thinning, and open small to large craniotomies. The Craniobot is built using off-the-shelf components for under $1000 and is controlled using open-source CNC programming software.

The advent of genetically encoded calcium indicators, along with surgical preparations such as thinned skulls or refractive index matched skulls, have enabled mesoscale cortical activity imaging in head-fixed mice. Such imaging studies have revealed complex patterns of coordinated activity across the cortex during spontaneous behaviors, goal-directed behavior, locomotion, motor learning, and perceptual decision making. However, neural activity during unrestrained behavior significantly differs from neural activity in head-fixed animals. Whole-cortex imaging in freely behaving mice will enable the study of neural activity in a larger, more complex repertoire of behaviors not possible in head-fixed animals. Here we present the “Mesoscope,” a wide-field miniaturized, head-mounted fluorescence microscope compatible with transparent polymer skulls recently developed by our group. With a field of view of 8 mm x 10 mm and weighing less than 4 g, the Mesoscope can image most of the mouse dorsal cortex with resolution ranging from 39 to 56 µm. Stroboscopic illumination with blue and green LEDs allows for the measurement of both fluorescence changes due to calcium activity and reflectance signals to capture hemodynamic changes. We have used the Mesoscope to successfully record mesoscale calcium activity across the dorsal cortex during sensory-evoked stimuli, open field behaviors, and social interactions. Finally, combining the mesoscale imaging with electrophysiology enabled us to measure dynamics in extracellular glutamate release in the cortex during the transition from wakefulness to natural sleep.

BACKGROUND:Sternum fractures are relatively uncommon injuries, which generally occur as a result of a high-energy mechanism and are often associated with significant concomitant injuries. These injuries may result in decreased quality of life if not properly addressed and yet are rarely operated on. The purpose of this project is to evaluate high-energy sternum fracture patterns using a previously published three-dimensional (3D) computed tomography (CT) reconstruction process to produce fracture frequency maps. METHODS:Patients 18 years and older presenting to a Level I trauma center with sternum fractures due to high-energy trauma between October 2013 and January 2022 were included. A 3D reconstruction and reduction was performed for each sternum using medical image processing software (Materialize NV, Leuven, Belgium). The reconstructions were subsequently overlaid onto a template sternum and normalized using bony landmarks. Fracture lines for each injured sternum were transferred onto the template, creating 3D frequency maps. RESULTS:A total of 120 patients met inclusion criteria. The study population had a uniform age distribution and 57.5% were male. The most common mechanism of injury was motor vehicle collision (64.2%). The breakdown of sternum fractures were isolated sternal body (55.8%), isolated manubrium (31.7%), and combined sternal body and manubrium fractures (12.5%). No xiphoid fractures were observed. Sternal body fractures were a near even mix of transverse (31.7%), oblique (32.9%), and comminuted (35.4%), while 75.5% of manubrium fractures were oblique. The most common associated injuries included rib fractures (80.8%) and traumatic brain injury (61.7%). CONCLUSION:This study presents the fractures from sternum injuries in 3D, and provides insight into reproducible sternum injury patterns that have not previously been analyzed in this format. This fracture mapping technique presents numerous injury patterns simultaneously, such that more frequent morphologies can be appreciated for different patient groups.

High-energy pelvic ring injuries are associated with significant morbidity and mortality, elevating the importance of injury pattern identification. The purpose of this study was to use a novel 3D computed tomography (CT) unfolding process to both evaluate high-energy pelvic ring injures and to produce injury frequency maps based on injury patterns.Methods: Patients 18-65 years of age presenting to a level 1 trauma center with pelvic ring injuries between 2016 and 2020 were identified. Of the 482 patients reviewed, 355 were excluded primarily due to having a low energy mechanism, inadequate radiographs, or an isolated fracture. Unfolded pelvic CT images were created using syngo.via CT Bone Reading software. Pelvic ring injury frequency maps were created using the unfolded pelvic CT images and a previously described mapping technique.Results: One hundred twenty-seven patients analyzed had a mean age of 32.7 years. The most common mechanisms of injury (MOI) were motor vehicle collision (30.7%) and fall from height (23.6%). The breakdown of pelvic ring injuries included LC1 = 44.1%, LC2 = 7.1%, LC3 = 14.2%, APC1 = 2.4%, APC2 = 15.0%, APC3 = 5.5%, and VS = 11.8%, with OTA/AO-61B = 74.0% and OTA/AO-61C = 26.0%. Pelvic ring mapping revealed that articular and bony injuries varied markedly between the different types of pelvic ring disruptions, both in type and location.Conclusions: Pelvic ring injury frequency maps created from unfolded CT images reflect consistent injury patterns providing distinctive information based on force vector mechanisms. Unfolded CT images allow for a novel way to visualize pelvic ring injuries which yield greater comprehension of failure patterns with implications for treatment.

Objective: Orthopaedic trauma implants may be electively explanted after fracture healing; reasons include symptomatic implants, cosmetic/functional concerns, or personal expectations. Certain institutions provide the option to keep implants after removal, although this has been retracted in others. This study examines patients' desire for return of implants, reasons for desiring return, and influence of return on perceptions of care.Methods: A cohort of adult patients who underwent elective orthopaedic implant removal by a single surgeon at a Level I trauma center between 2008 and 2019, with the option to keep their removed implants, was identified. Surveys were sent to patients with contact information. Demographics, reasons for removal, satisfaction, and perceptions of care were studied. Results:The overall response rate was 47.4% (117 of 247).Respondents' mean age was 46.9 years, and 50% were female. Ninety-one percent kept their implants. Eighty-nine percent of patients felt that removal achieved their desired outcome, with decreasing pain cited as primary motivation for explantation (62%). Forty-five percent reported a strong desire to keep their implants, most commonly to show to family (49%). Seventy-four percent were happy to have this option. Thirty-seven percent of patients reported respecting their provider more for having this option, and 27% reported that this positively impacted their satisfaction.Conclusions: Patients perceive elective implant removal as highly effective. A majority were pleased to have the option to keep their implants, and many reported increased respect and satisfaction. Thus, providing patients with this option should be strongly considered to honor patient choice and optimize outcomes when feasible.