Quantifying Aerosol Generation in Maxillofacial Trauma Repair Techniques

Study Design Cadaveric simulation study. Objective The novel coronavirus (COVID-19), which can be transmitted via aerosolized viral particles, has directed focus on protection of healthcare workers during procedures involving the upper aerodigestive tract, including maxillofacial trauma repair. This study evaluates particle generation at different distances from open reduction and internal fixation (ORIF) of maxillofacial injuries in the intraoperative setting to reduce the risk of contracting airborne diseases such as COVID-19. Methods Two cadaveric specimens in a simulated operating room underwent ORIF of midface and mandible fractures via intraoral incisions as well as maxillomandibular fixation (MMF) using hybrid arch bars. ORIF was performed with both self-drilling screws and with the use of a power drill for creating guide holes. Real-time aerosol concentration was measured throughout each procedure using 3 particle counters placed 0.45, 1.68, and 3.81 m (1.5, 5.5, and 12.5 feet, respectively) from the operative site. Results There was a significant decrease in particle concentration in all procedures at 1.68 m compared to 0.45 m, but only 2 of the 5 procedures showed further significant decrease in particle concentration when going from 1.68 to 3.81 m from the operative site. There was significantly less particle concentration generated at all distances when using self-drilling techniques compared to power drilling for ORIF. Conclusion Consideration of using self-drilling screwing techniques as well as maintaining physical distancing protocols may decrease risk of transmission of airborne diseases such as COVID-19 while in the intraoperative setting.

Impact of Anterior Clinoidectomy on Visual Function After Paraclinoid Carotid Artery Aneurysm Surgery: Power-Drill Versus No-Drill Technique

ABSTRACT BACKGROUND Few studies have attempted to make a direct comparison of the risk of visual impairment following extradural anterior clinoidectomy (EAC) with and without the use of a power drill. OBJECTIVE To evaluate postoperative visual outcomes between groups of patients with paraclinoid carotid artery aneurysms (PCAAs) who underwent surgical clipping with and without the use of a power drill during EAC. METHODS Between January 2010 and November 2019, 90 patients, 7 with ruptured and 83 with unruptured PCAAs, underwent clipping surgery at our hospital. The authors retrospectively analyzed postoperative visual complications from the medical records of these patients. RESULTS Among the 85 patients (excluding 3 patients with disturbance of consciousness caused by subarachnoid hemorrhage and 2 patients with preoperative visual disturbance) evaluated, EAC was conducted using a power drill in 64 patients and using a microrongeur in 21 patients. Permanent postoperative visual impairment developed in 14 (21.9%) patients in the drill group: 9 patients had ipsilateral lower nasal quadrant hemianopsia (ILNQH) and 5 patients had ipsilateral visual acuity reduction. Transient ILNQH developed in only 1 patient in the no-drill group. The incidence of permanent postoperative visual impairments was significantly lower in the no-drill group than in the drill group (P = .020). Seventeen (26.6%) patients developed transient oculomotor nerve palsy in the drill group, while no patients developed oculomotor nerve palsy in the no-drill group. CONCLUSION EAC using a microrongeur versus a power drill significantly improved visual outcomes after clipping surgery for PCAAs.

Reconstruction of Craniectomy for Microvascular Decompression with Autologous Particulate Bone

Background and Study Objective Cranioplasty after microvascular decompression (MVD) is important for preventing postoperative complications such as headache. Autologous particulate bone is a common material for cranioplasty. The purpose of this study was to evaluate the effect of using autologous particulate bone to reconstruct the cranial defect produced by MVD. Patients and Methods Data were collected from January 2013 to December 2016 from 243 patients who underwent suboccipital retrosigmoidal craniectomy for MVD. The patients were then further divided into two groups: in the first group (from January 2013–October 2015), a cranioplasty was performed using a combination of bone dust (taken from a power drill) and particulate bone (harvested with a rongeur); in the second group (from November 2015–December 2016), the cranial defect was reconstructed using particulate bone alone. Healing of the cranial defect was observed during the follow-up. Results Early postoperative computed tomography (CT), performed during the hospital stay, revealed that the filling of the cranial defects of the first group was better than that of the second group. In addition, surgical-site infections (SSIs) occurred in 13 patients in the first group (9.92%) versus 2 patients in the second group (1.79%). The SSI rate of the first group was significantly higher than that of the second group (p < 0.05). Long-term follow-up CT demonstrated that the average reconstruction rate ((volume of the reconstruction area)/(volume of the cranial defect) × 100%) was 47.88% for the first group and 43.94% for the second group (p > 0.05). Conclusion The use of autologous particulate bone to reconstruct cranial defects after MVD has a good effect and is thus a useful and valuable technique. Bone dust may result in a higher incidence of SSI.

Non-cuttable material created through local resonance and strain rate effects

We have created a new architected material, which is both highly deformable and ultra‐resistant to dynamic point loads. The bio-inspired metallic cellular structure (with an internal grid of large ceramic segments) is non-cuttable by an angle grinder and a power drill, and it has only 15% steel density. Our architecture derives its extreme hardness from the local resonance between the embedded ceramics in a flexible cellular matrix and the attacking tool, which produces high-frequency vibrations at the interface. The incomplete consolidation of the ceramic grains during the manufacturing also promoted fragmentation of the ceramic spheres into micron-size particulate matter, which provided an abrasive interface with increasing resistance at higher loading rates. The contrast between the ceramic segments and cellular material was also effective against a waterjet cutter because the convex geometry of the ceramic spheres widened the waterjet and reduced its velocity by two orders of magnitude. Shifting the design paradigm from static resistance to dynamic interactions between the material phases and the applied load could inspire novel, metamorphic materials with pre-programmed mechanisms across different length scales.