Iatrogenic Peroneal Nerve Palsy Rates Secondary to Open Reduction Internal Fixation for Tibial Plateau Fractures Using an Intraoperative Distractor

Objective: To report the rate of peroneal nerve palsy after routine use of intraoperative distraction during open reduction internal fixation (ORIF) for lateral unicondylar and bicondylar tibial plateau fracture (TPF) repairs. Design: Retrospective chart review Setting: Level I trauma center Patients: Patients with traumatic TPF treated with ORIF between 2007 and 2017 Intervention: ORIF for lateral unicondylar and bicondylar TPF. Main Outcome Measurement: Presence and resolution of neurovascular injury Results: There were a total of 21 lateral unicondylar and 40 bicondylar TPFs repaired via ORIF in 60 patients identified during the study period with one year follow up and complete records for review. Thirty-six patients had staged external fixation prior to ORIF while 24 were treated with ORIF initially. Of the staged patients, 9 of 36 (25%) developed nerve palsy while those undergoing initial ORIF (not staged) developed palsy in only one case (1 of 24, or 4%). Of the patients who developed nerve palsy 9 of 10 (90%) were staged with an initial external fixator prior to ORIF. The incidence of iatrogenic peroneal nerve palsy secondary to intraoperative distraction was 16.4% (10 of 61). Only 60% (6 of 10) of peroneal nerve palsies recovered clinically with a mean recovery time of approximately 14 weeks. Comparison of demographics in patients with peroneal nerve palsy versus those without yielded no significant difference by sex (p = 0.08), age (p =0.27), fracture type (p = 0.29), tobacco use (p = 0.44) or alcohol use (p = 0.78). Conclusions: Peroneal nerve palsy is a common sequela of ORIF for TPFs involving the lateral compartment utilizing an intraoperative distractor. Staged external fixation followed by definitive ORIF using intra-operative distraction, was associated with significant risk for developing nerve palsy (9/10). Many patients (40%) who develop peroneal nerve palsies do not recover, leading to permanent loss of motor and/or sensory function for 7% of patients studied. None of the epidemiologic variables evaluated yielded predictive value for development of peroneal nerve palsy or subsequent resolution. Caution should be exercised in avoiding over distraction when using intraoperative distraction, especially in those cases that had staged fixation, most notably bicondylar injuries

Medical Telementoring Using an Augmented Reality Transparent Display

Background The goal of this study was to design and implement a novel surgical telementoring system called the System for Telementoring with Augmented Reality (STAR) that uses a virtual transparent display to convey precise locations in the operating field to a trainee surgeon. This system was compared with a conventional system based on a telestrator for surgical instruction. Methods A telementoring system was developed and evaluated in a study which used a 1 × 2 between-subjects design with telementoring system, that is, STAR or conventional, as the independent variable. The participants in the study were 20 premedical or medical students who had no prior experience with telementoring. Each participant completed a task of port placement and a task of abdominal incision under telementoring using either the STAR or the conventional system. The metrics used to test performance when using the system were placement error, number of focus shifts, and time to task completion. Results When compared with the conventional system, participants using STAR completed the 2 tasks with less placement error (45% and 68%) and with fewer focus shifts (86% and 44%), but more slowly (19% for each task). Conclusions Using STAR resulted in decreased annotation placement error, fewer focus shifts, but greater times to task completion. STAR placed virtual annotations directly onto the trainee surgeon's field of view of the operating field by conveying location with great accuracy; this technology helped to avoid shifts in focus, decreased depth perception, and enabled fine-tuning execution of the task to match telementored instruction, but led to greater times to task completion

Overlapping Surgery for Ankle Fractures: Is It Safe?

Objective: To determine whether the practice of overlapping surgery influenced patient safety after open reduction internal fixation (ORIF) for ankle fractures. Design: Retrospective case–control. Setting: Level 1 Academic Midwest trauma center. Patients: All patients who underwent ankle fracture ORIF by a single surgeon were eligible for our study, with 478 total patients. Intervention: Cases that were overlapping were compared against cases that were not overlapping. Cases were defined as overlapping if there was greater than 30 minutes of overlap between procedural times. Patient complications were recorded up to a year from the index surgery. Main Outcome Measure: Unexpected return to surgery. Results: There were 478 ankle fracture ORIF patients, 238 with at least 3 months follow-up; 124 (52%) in the overlapping group and 114 (48%) in the nonoverlapping group. There was no difference in the rate of unexpected return to surgery (P = 0.76), infection (P = 0.52), readmission (P = 0.96), painful implant (P = 0.62), malunion (P = 0.27), nonunion (P = 0.52), or arthritis (P = 0.39) between the overlapping and nonoverlapping groups. There were 467 isolated ankle fractures used for time analysis. Average procedure time was 26 minutes longer for the overlapping group than the nonoverlapping group (P < 0.01). Conclusions: Overlapping surgery causes increased operative time for ankle ORIF, but there was no apparent increased risk to the patients for short-term complications. The need for graduated resident responsibility required by ACGME guidelines need to be weighed against the decreased efficiency of operating room time

Arthroscopy Should be Used With Caution for Gunshot Wounds to the Hip

Purpose: To evaluate the safety and efficacy of hip arthroscopy immediately following gunshot wound (GSW) to the hip. Methods: Patients who received hip arthroscopy for GSWs from 2006 to 2020 by 2 surgeons at a level I trauma center were identified by Current Procedural Terminology codes. Inclusion criteria were those patients who suffered a GSW to the hip, received hip arthroscopy for treatment, and had a minimum follow-up of 2 months. The exclusion criteria were any patients younger than 18 years of age. Medical records were reviewed for patient demographics, surgical details, clinical outcomes, and complications. Results: A total of 50 hip arthroscopy cases were identified by Current Procedural Terminology codes. Of the 50 cases identified, 8 patients met the inclusion criteria. All 8 patients were male, African-American, and the mean age was 31 years (range, 19-54 years) with mean follow-up of 14 months. Five of 8 cases were noted to have poor visualization with arthroscopy. Common reasons for poor visualization were difficult access to the bullet fragments, morbid obesity, hematoma formation, and pre-existing arthritis. Of these 5 cases, 2 were converted to open procedures to retrieve the remaining bullet fragments. One patient developed abdominal compartment syndrome, most likely due to increased pulse pressure over a prolonged operative period and involvement of the acetabular fovea. Emergent exploratory laparotomy and abdominal compartment fluid release were performed, and the patient had an otherwise unremarkable hospital course. Conclusions: There are risks with the use of arthroscopic methods to remove GSW fragments, which may be greater than elective hip arthroscopy. Certain factors, such as the surgeon's arthroscopic experience, locations of bullets fragments, visual quality, length of procedure, and concomitant acetabular fractures, must be considered before proceeding with arthroscopy. Level of evidence: Therapeutic case series

Augmented Reality Future Step Visualization for Robust Surgical Telementoring

Introduction Surgical telementoring connects expert mentors with trainees performing urgent care in austere environments. However, such environments impose unreliable network quality, with significant latency and low bandwidth. We have developed an augmented reality telementoring system that includes future step visualization of the medical procedure. Pregenerated video instructions of the procedure are dynamically overlaid onto the trainee's view of the operating field when the network connection with a mentor is unreliable. Methods Our future step visualization uses a tablet suspended above the patient's body, through which the trainee views the operating field. Before trainee use, an expert records a “future library” of step-by-step video footage of the operation. Videos are displayed to the trainee as semitransparent graphical overlays. We conducted a study where participants completed a cricothyroidotomy under telementored guidance. Participants used one of two telementoring conditions: conventional telestrator or our system with future step visualization. During the operation, the connection between trainee and mentor was bandwidth throttled. Recorded metrics were idle time ratio, recall error, and task performance. Results Participants in the future step visualization condition had 48% smaller idle time ratio (14.5% vs. 27.9%, P < 0.001), 26% less recall error (119 vs. 161, P = 0.042), and 10% higher task performance scores (rater 1 = 90.83 vs. 81.88, P = 0.008; rater 2 = 88.54 vs. 79.17, P = 0.042) than participants in the telestrator condition. Conclusions Future step visualization in surgical telementoring is an important fallback mechanism when trainee/mentor network connection is poor, and it is a key step towards semiautonomous and then completely mentor-free medical assistance systems

Chandra Observations of the Cl1604 Supercluster at z=0.9: Evidence for an Overdensity of Active Galactic Nuclei

We present the results of Chandra observations of the Cl1604 supercluster at z~0.9. The system is the largest structure mapped at redshifts approaching unity, containing at least eight spectroscopically confirmed galaxy clusters and groups. Using two 50-ksec ACIS-I pointings we examine both the X-ray point source population and the diffuse emission from individual clusters in the system. We find a 2.5\sigma excess of point sources detected in the hard band (2-10 keV) relative to the number of sources found in blank fields observed by Chandra. No such excess is observed in the soft band (0.5-2 keV). The hard-band source density is 1.47 times greater than that of a blank field, in agreement with the previously reported correlation between overdensity amplitude and cluster redshift. Using a maximum likelihood technique we have matched 112 of the 161 detected X-ray point sources to optical counterparts and found 15 sources that are associated with the supercluster. All 15 sources have rest-frame luminosities consistent with emission from active galactic nuclei (AGN). We find that the supercluster AGN largely avoid the densest regions of the system and are instead distributed on the outskirts of massive clusters or within poorer clusters and groups. We have also detected diffuse emission from two of the eight clusters and groups in the system, clusters Cl1604+4304 and Cl1604+4314. The systems have bolometric luminosities of 1.43x10^44 and 8.20x10^43 h70^-2 erg s^-1 and gas temperatures of 3.50 (+1.82-1.08) and 1.64 (+0.65-0.45) keV, respectively. Using updated velocity dispersions, we compare the properties of these systems to the cluster scaling relations followed by other X-ray and optically selected galaxy clusters at high redshift.Comment: 24 pages, 14 figures, submitted to Ap

Potential Benefits of Limited Clinical and Radiographic Follow-up After Surgical Treatment of Ankle Fractures

Introduction: Ankle fractures are one of the most prevalent musculoskeletal injuries, with a significant number requiring surgical treatment. Postoperative complications requiring additional interventions frequently occur during the early postoperative period. We hypothesize that there is a limited need for routine clinical and radiographic follow-up once the fracture is deemed healed. Methods: IRB approval was obtained at four academic trauma centers. A retrospective chart review was done to identify adults with healed unimalleolar and bimalleolar ankle fractures treated surgically with at least 12 months of follow-up. Based on postoperative radiographs, changes in fracture alignment and implant position from radiographic union to final follow-up were documented. The average reimbursement for a final follow-up clinic visit and a set of ankle radiographs were estimated. Results: A total of 140 patients met inclusion criteria. The mean age at injury was 49.5 years, and 67.9% of patients were female. The mean time to healing was 82.2 days (±33.5 days). After radiographic healing, one patient had radiographic changes but was asymptomatic and full weight bearing at their final follow-up. On average, our institution was reimbursed $46 to$49 for a follow-up clinic visit and $364 to$497 for a set of ankle radiographs. Conclusion: Given the average time to healing, there is limited utility in routine radiographic and clinical follow-up beyond 16 weeks in asymptomatic patients. In our series, this would result in a savings of $950 to$1,200 per patient. However, after ankle fractures were deemed healed, 0.7% patients had radiographic evidence of a change in implant position. Documenting this change did not modify the immediate course of fracture treatment. Surgeons will need to balance the need for routine follow-up with the potential economic benefits in reducing costs to the healthcare system

Compilation of a panel of informative single nucleotide polymorphisms for bovine identification in the Northern Irish cattle population

<p>Abstract</p> <p>Background</p> <p>Animal identification is pivotal in governmental agricultural policy, enabling the management of subsidy payments, movement of livestock, test scheduling and control of disease. Advances in bovine genomics have made it possible to utilise inherent genetic variability to uniquely identify individual animals by DNA profiling, much as has been achieved with humans over the past 20 years. A DNA profiling test based on bi-allelic single nucleotide polymorphism (SNP) markers would offer considerable advantages over current short tandem repeat (STR) based industry standard tests, in that it would be easier to analyse and interpret. In this study, a panel of 51 genome-wide SNPs were genotyped across panels of semen DNA from 6 common breeds for the purposes of ascertaining allelic frequency. For SNPs on the same chromosome, the extent of linkage disequilbrium was determined from genotype data by Expectation Maximization (EM) algorithm. Minimum probabilities of unique identification were determined for each breed panel. The usefulness of this SNP panel was ascertained by comparison to the current bovine STR Stockmarks II assay. A statistically representative random sampling of bovine animals from across Northern Ireland was assembled for the purposes of determining the population allele frequency for these STR loci and subsequently, the minimal probability of unique identification they conferred in sampled bovine animals from Northern Ireland.</p> <p>Results</p> <p>6 SNPs exhibiting a minor allele frequency of less than 0.2 in more than 3 of the breed panels were excluded. 2 Further SNPs were found to reside in coding areas of the cattle genome and were excluded from the final panel. The remaining 43 SNPs exhibited genotype frequencies which were in Hardy Weinberg Equilibrium. SNPs on the same chromosome were observed to have no significant linkage disequilibrium/allelic association. Minimal probabilities of uniquely identifying individual animals from each of the breeds were obtained and were observed to be superior to those conferred by the industry standard STR assay.</p> <p>Conclusions</p> <p>The 43 SNPs characterised herein may constitute a starting point for the development of a SNP based DNA identification test for European cattle.</p

Using Microsatellites to Understand the Physical Distribution of Recombination on Soybean Chromosomes

Soybean is a major crop that is an important source of oil and proteins. A number of genetic linkage maps have been developed in soybean. Specifically, hundreds of simple sequence repeat (SSR) markers have been developed and mapped. Recent sequencing of the soybean genome resulted in the generation of vast amounts of genetic information. The objectives of this investigation were to use SSR markers in developing a connection between genetic and physical maps and to determine the physical distribution of recombination on soybean chromosomes. A total of 2,188 SSRs were used for sequence-based physical localization on soybean chromosomes. Linkage information was used from different maps to create an integrated genetic map. Comparison of the integrated genetic linkage maps and sequence based physical maps revealed that the distal 25% of each chromosome was the most marker-dense, containing an average of 47.4% of the SSR markers and 50.2% of the genes. The proximal 25% of each chromosome contained only 7.4% of the markers and 6.7% of the genes. At the whole genome level, the marker density and gene density showed a high correlation (R2) of 0.64 and 0.83, respectively with the physical distance from the centromere. Recombination followed a similar pattern with comparisons indicating that recombination is high in telomeric regions, though the correlation between crossover frequency and distance from the centromeres is low (R2 = 0.21). Most of the centromeric regions were low in recombination. The crossover frequency for the entire soybean genome was 7.2%, with extremes much higher and lower than average. The number of recombination hotspots varied from 1 to 12 per chromosome. A high correlation of 0.83 between the distribution of SSR markers and genes suggested close association of SSRs with genes. The knowledge of distribution of recombination on chromosomes may be applied in characterizing and targeting genes