Delayed Presentation of Popliteal Artery Injury after Salter-Harris III Proximal Tibia Fracture.

Introduction: Proximal tibia physeal fractures in children are not very common but can be dangerous because they can harm popliteal fossa structures, especially the popliteal artery. Popliteal artery injuries (PAI) are most commonly the result of trauma to the lower extremity, including blunt force, hyperextension injuries, complex fractures, and knee dislocations that can compromise popliteal neurovascular structures. Case Presentation. A 14-year-old boy presents to the emergency department after being transferred from an outside hospital 24 hours after a left lower extremity hyperextension injury. Radiographs demonstrated a Salter-Harris III proximal tibia fracture with posterior displacement. ABIs were deferred due to palpable distal pulses and no evidence of compartment syndrome. Closed reduction and percutaneous pinning were planned to correct the fracture. Intraoperatively, it was discovered that knee extension decreased lower extremity perfusion while knee flexion returned perfusion. An angiography revealed a popliteal artery occlusion with no distal flow. Based on this, an above-knee to below-knee popliteal bypass using the contralateral great saphenous vein was performed followed by closed reduction and percutaneous pinning of the proximal tibia. Conclusion: Proximal tibia physeal injuries, especially the Salter-Harris III and IV injuries, warrant a high index of suspicion of popliteal artery injuries. Palpable pulses and delayed presentation in the distal lower extremity do not rule out a PAI because collateral flow to the anterior and posterior tibial arteries may mask signs of an avascular limb, highlighting the need for a thorough history and physical exam. The authors present this case to reaffirm the importance of an ankle-brachial index when evaluating hyperextension injuries with proximal tibial epiphyseal fractures.

Analysis of risk factors for nonunion in pediatric lateral column lengthening.

The lateral column lengthening procedure is a commonly used osteotomy for correction of pes planus performed by inserting a graft in the anterior aspect of the calcaneus through a transverse osteotomy. Though nonunion and calcaneo-cuboid subluxation have been previously reported, these complications have not been extensively studied in pediatric patients. After IRB approval, 111 patients (151 feet) who underwent lateral column lengthening at a single institution were identified. Fifty-three females (70 feet) and 58 males (81 feet) with an average age of 11.4 years (2.6 SD; range 5-17) were analyzed. The primary outcome was nonunion defined as a lack of radiographic evidence of osteotomy healing by 9 months. Underlying diagnosis, pre and postoperative radiographic measurements, age, operative technique, fixation, calcaneo-cuboid subluxation, graft material and concomitant procedures were analyzed for their relationship to nonunion. Nonunion occurred in 7 of 151 feet (4.6%). Patient age at the time of surgery and calcaneo-cuboid subluxation trended toward a significant association with nonunion ( P = 0.053, 0.054, respectively). The degree of surgical correction, as determined by radiographic analysis, and the use of calcaneo-cuboid fixation were not significantly associated with nonunion. None of the other factors evaluated were significantly associated with nonunion. There were three cases of postoperative infections (2.0%), two were superficial and 1 (0.7%) was deep. Thirty-five of 151 feet disclosed radiographic evidence of subluxation. Excluding subluxation, the overall complication rate was 8.6%. Nonunion occurred in 4.6% of pediatric feet undergoing lateral column lengthening. Fixation type was not significantly associated with nonunion. Older age at the time of surgery and calcaneocuboid subluxation trended towards significance. The placement of a calcaneo-cuboid pin was not found to be a significant factor in preventing calcaneo-cuboid subluxation or nonunion.

Increased open fracture complications following pediatric all-terrain vehicle accidents.

BACKGROUND: ATV (All-Terrain Vehicle) related open fractures are often high energy and may be highly contaminated. We asked whether they were more complicated than other open fractures in pediatric patients. METHODS: A retrospective chart review was performed comparing ATV associated open fractures to open fractures sustained in non-ATV related accidents. 97 pediatric open fractures from 2015 to 2021 were identified based on ICD-10 codes. Of these fractures, 62 were non-ATV related and 35 were ATV related. Charts were reviewed to collect basic demographics, fracture pattern, Gustilo-Anderson classification, procedures performed, operative findings, and complications. RESULTS: Our cohort was predominantly male (71% in the ATV group and 76% in the non-ATV group). White race was more common in both the ATV (28 (80%)) and non-ATV (50(78%)) groups. The distribution of AO/OTA fractures was significantly different (p = 0.046), with humerus fractures being more common in the ATV group (8 (22%)) vs. non-ATV group (6 (9.3%)). The ATV group had a higher proportion of more severe type II and III open fractures with 77.1% (n = 27), versus 56% (n = 35) in the non-ATV group (p = 0.020).. Revision and reoperation were more likely in the ATV group (16 (23%)) vs. the non-ATV group (12 (15%)), as was malunion (ATV group 3 (4.3%) Vs. non-ATV 0 (0%)). CONCLUSION: Open fractures resulting from ATV injuries tend to be more complex and have higher rates of revision and malunion. This information supports the large body of evidence on the dangers of ATVs to children and can help guide expectations of both clinicians and family members of patients presenting with these injuries.

Pediatric hallux valgus: An overview of history, examination, conservative, and surgical management.

Pediatric hallux valgus (PHV), while relatively rare, is still often encountered by general pediatricians. Herein, we concisely summarize the existing literature regarding the pathogenesis, associated conditions, clinical diagnosis, radiographic characteristics, conservative management, and surgical management of PVH. Though PHV is generally considered benign, the progression of hallux valgus can result in complications. The presence of an open physis in the pediatric age group delineates first line treatment choices, whenever possible, as nonoperative. The general exception to this recommendation is for children with neuromuscular and connective tissues disease who may benefit from earlier surgical management. If conservative approaches fail prior to skeletal maturity, the risk of recurrence and need for revision surgery should be discussed with patients and their families before surgical referral is made. The current review was conducted to aid primary care providers in better understanding the pathogenesis, associated conditions, and intervention options available to manage PHV.

Simulation Neurotechnologies for Advancing Brain Research: Parallelizing Large Networks in NEURON.

Large multiscale neuronal network simulations are of increasing value as more big data are gathered about brain wiring and organization under the auspices of a current major research initiative, such as Brain Research through Advancing Innovative Neurotechnologies. The development of these models requires new simulation technologies. We describe here the current use of the NEURON simulator with message passing interface (MPI) for simulation in the domain of moderately large networks on commonly available high-performance computers (HPCs). We discuss the basic layout of such simulations, including the methods of simulation setup, the run-time spike-passing paradigm, and postsimulation data storage and data management approaches. Using the Neuroscience Gateway, a portal for computational neuroscience that provides access to large HPCs, we benchmark simulations of neuronal networks of different sizes (500-100,000 cells), and using different numbers of nodes (1-256). We compare three types of networks, composed of either Izhikevich integrate-and-fire neurons (I&F), single-compartment Hodgkin-Huxley (HH) cells, or a hybrid network with half of each. Results show simulation run time increased approximately linearly with network size and decreased almost linearly with the number of nodes. Networks with I&F neurons were faster than HH networks, although differences were small since all tested cells were point neurons with a single compartment.