Minimizing the Risk of Vascular Injury: Anatomy of the Popliteal Artery in the Pediatric Knee.

BACKGROUND: Displaced pediatric tibial tubercle fractures are commonly stabilized with screws directed posteriorly toward neurovascular structures. Here, we (1) characterize the variation of the popliteal artery among pediatric patients; and (2) recommend a safe screw trajectory for fixation of tibial tubercle fractures. METHODS: We retrospectively identified 42 patients (42 knees; 29 female) aged 12-17 years with lower-extremity magnetic resonance imaging (MRI) at a tertiary academic center. The mean patient age was 14.5 (range: 12-17) years, and the mean body mass index value was 19.1 (range: 14.9-25.1). We included patients with open physes or visible physeal scars and excluded those with prior instrumentation or lower-extremity injury. Using sagittal MRI, we measured the distances from 5 levels each on the anterior and posterior tibial cortex to the popliteal artery (level 1, midpoint of proximal tibial epiphysis; level 2, the proximal extent of the tubercle; level 3, tubercle prominence; level 4, 2 cm distal to the proximal extent of the tubercle; level 5, 4 cm distal to the proximal extent of the tubercle). Using coronal MRI, we measured the width of the tibia at each level and the distance from the lateral-most and medial-most cortex to the artery. RESULTS: The popliteal artery was laterally positioned in all knees. The mean distance between the artery and lateral-most aspect of the tibia at each level ranged from 1.9 to 2.4 cm, and from 2.3 to 3.9 cm from the medial-most aspect of the tibia. The mean distance that a screw can advance before vascular injury was 5.1 cm at level 1. The shortest mean distance to the popliteal artery was 1.7 cm, at level 5. There is minimal distance between the posterior tibial cortex and the artery at all levels. CONCLUSIONS: Understanding the position of the popliteal artery in pediatric patients can help when stabilizing tibial tubercle fractures. Because the artery is close to the posterior cortex, a drill exiting in line with the popliteal artery risks vascular injury. Therefore, we recommend that screws exit within the medial 60% of the tibia. LEVEL OF EVIDENCE: IV.

Evaluating the sagittal spinal and pelvic parameters in Marfan syndrome patients affected by scoliosis.

INTRODUCTION: Spinal deformities present a common finding in patients affected with Marfan syndrome (MFS). More specifically, sagittal spine imbalances reflect the typical finding of such deformities. Observing spino-pelvic radiographs, we focused on eliciting any correlation between the pelvic incidence (PI), sacral slope (SS) and thoracolumbar kyphosis measurements, and categorising them according to a sagittal spinal classification system. MATERIALS AND METHODS: One hundred seventy patient records were found over a 6 year period, and further refined to incorporate a total of 44 patients. 25 males and 19 females with an average age of 20 years at imaging. Electronic and hard copies of radiographs were used and measurements were made with virtual Cobb meters, rulers and protractors. RESULTS: The mean PI was significantly different between type-I (46°) and type-II spines (35°) (p = 0.04), and the values for each class were as follows: type IA-53°, type IB-44°, type IC-36°, type IIA-42°, and type IIB-34°. Type II spines had a lower PI compared to type IA spines (p = 0.037) and to that of an unaffected population. Statistically significant differences were noted in SS between groups (t test; p < 0.001), and ANOVA demonstrated that the largest differences between spinal classes were found in SS. CONCLUSION: In our study, PI values were much higher in type I compared to type II spines. Type II spines had PI values as expected, however, had higher than expected SS values. SS followed a down trending pattern across all spinal classes. Type IIA spines had a much greater preponderance for male patients. Overall, we wish to highlight in particular that type II spines were associated with a much lower PI and SS, and report these differences in pelvic morphology and sagittal spine patterns seen in MFS patients. The pelvic tilt and sacral slope parameters observed in our Type II spines may further reflect and characterize the deformity.

Blunt vertebral vascular injury in trauma patients: ATLS® recommendations and review of current evidence.

Blunt cerebrovascular injury (BCVI) encompasses two distinct clinical entities: traumatic carotid artery injury (TCAI) and traumatic vertebral artery injury (TVAI). The latter is the focus of our review. These are potentially devastating injuries which pose a diagnostic challenge in the acute trauma setting. There is still debate regarding the optimal screening criteria, diagnostic imaging modality and treatment methods. In 2012 the American College of Surgeons proposed criteria for investigating patients with suspected TVAI and subsequent treatment methods, caveated with the statement that evidence is limited and still evolving. Here we review the historical evidence and recent literature relating to these recommendations.