Variability in rod to bone distance needed in pelvic subcutaneous internal fixation to avoid nerve compression: A tridimensional population-based study.

INTRODUCTION: Pelvic internal fixation has become a popular method for treatment of unstable pelvic ring injuries. Although successful, one complication is femoral nerve palsy from compression of the connecting rod. In light of this complication, this study was designed to evaluate sagittal inclinations of the rod and the feasibility of using a rod with a constant curvature. HYPOTHESIS: It is hypothesized that that there is a connection between the sagittal inclination of the rod and the rod to bone distance, as well as single rod can be contoured with a constant curvature to be used in the majority of all patients. METHODS: Three dimensional models of pelvis CTs from a single level 1 trauma center were created and imported into a program where software superimposed a pre-contoured rod in the sagittal planes upon the pelvic slices. The sagittal inclination was deemed acceptable is no interference occurred between the area of compression risk and the rod. For each pelvis and considered sagittal rod inclination, the rod radius of curvature (ROC), minimal rod to bone distance (RTB) and transverse inclinations (φL and φR) were measured at which the pedicle screws should be inserted to follow the direction of the smallest RTB. RESULTS: The sagittal inclinations feasible for all subjects were between 15° to 30°. In this sagittal range, the average RTB varied in values ranging from 4.0±0.9mm to 25.4±11.4mm (p<0.01). Only 46% of subjects allowed a rod with constant curvature. DISCUSSION AND CONCLUSION: Our study found that a rod to bone distance of 15mm was not safe for all models. As well, many subject models did not allow placement of pre-contoured rod. Patient specific templating of pelvic subcutaneous internal fixation is strictly needed to limit complications. LEVEL OF EVIDENCE: VII; Basic Science.

Adapting Orthopaedic Surgery Training Programs During the COVID-19 Pandemic and Future Directions.

The COVID-19 pandemic swept across the world, altering the structure and existence of graduate medical education programs across all disciplines. Orthopaedic residency programs can adapt during these unprecedented times to continue providing meaningful education to trainees and to continue providing high-quality patient care, all while keeping both residents and patients safe from disease. The purpose of this review was to evaluate the literature and describe evidence-based changes that can be made in an orthopaedic residency program to ensure patient and resident safety while sustaining the principles of graduate medical education during the COVID-19 pandemic. We describe measures that can be enacted now or during future pandemics, including workforce and occupational modifications, personal protective equipment, telemedicine, online didactic education, resident wellness, return to elective surgery, and factors affecting medical students and fellows. After a review of these strategies, programs can make changes for sustainable improvements and adapt to be ready for second-wave events or future pandemics. LEVEL OF EVIDENCE: Level V.

Achievable pin spanning angulation in anterosuperior pelvic external fixation.

INTRODUCTION: Pelvic external fixation using anterosuperior pins provides a quick method of stabilization without necessitating fluoroscopic guidance. Various locations, depths, and inclinations have been cited for external fixator pins; however, the existing literature lacks clear indications for the angular difference between pins. Thus, we aimed to determine the greatest degree of sagittal pin spanning angulation (SPSA) between two iliac crest pins and how intraosseous depth (ID) affects these angulations. MATERIALS AND METHODS: A newly developed computer algorithm produced cross sections of 3D pelvic reconstructions in the sagittal plane in 5° increments. Computer-generated pins with IDs of 60, 75, and 90 mm were positioned in 5° increments transversely. Pins were assessed for cortical containment to define values for SPSA and transverse pin spanning angulation (TPSA). RESULTS: A bimodal distribution revealed varying degrees of insertion frequency and SPSA, cranially and caudally. The caudal distribution exhibited greater cortical containment with larger values for SPSA and TPSA. The highest insertion frequency (85.7%) and largest SPSA (155°) were observed for the 60-mm ID. Increasing ID resulted in further bony penetration and smaller values for SPSA and TPSA. CONCLUSIONS: Expanding the degree of SPSA between inserted pins in anterosuperior pelvic external fixation can be challenging due to the thinning of the iliac wing, which affords a narrow corridor for intraosseous pin containment. An ID of 60 mm allows larger degrees of SPSA while maintaining higher rates of cortical pin containment when compared to pins with greater IDs.

Safe Supra-Acetabular Pin Insertion in Relation to Intraosseous Depth.

In pelvic fractures, dysfunction of the pelvic ring is often stabilized with supra-acetabular pin insertion. In existing literature, there are heterogeneous indications on proper pins selection and inclinations. Therefore, this study aimed to quantify the narrowing of safe pin corridors in the transverse and sagittal planes with increments of intraosseous screw depths. A computer algorithm created cross-sections over three-dimensional pelvic reconstructions at sagittal inclinations from 45° cranial to 45° caudal in 5° increments. Templates of screw depths spanning 60-120 mm in 15 mm increments were disposed in the transverse plane from 45° medial to 45° lateral. Each intraosseous screw depth and transverse angle were evaluated for intraosseous containment to evaluate ranges narrowing with increasing screw depths. The 60-mm depth resulted in the largest sagittal range (60.9° ± 6.9°) and transverse range (27.5° ± 4.1°) at 30° caudal. Increasing depths by 15 mm resulted in ranges being significantly different from one another (p < 0.01). The sagittal plane of 20° cranial had the highest frequency of insertion for all depths, while transverse ranges were narrowed (p < 0.01). Bisecting angles were similar for sagittal planes 20° cranial to 30° caudal with an average of 27.9° ± 1.2° (p ≥ 0.115). In conclusion, while 60 mm depths can be inserted with the highest discretion, 15 mm increments in depth significantly reduce safe ranges. Screws depths above 90 mm have low frequencies of insertion, should be inserted more cranially and must be considered prone to breaching. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 37:1790-1797, 2019.

A Nonoperative Approach for Neurosurgical Management of a Sylvian Fissure Dermoid Cyst.

The nonoperative management of sylvian fissure dermoid/epidermoid cysts presents a risk that is difficult to quantify. With rupture, potentially fatal complications such as chemical meningitis, hydrocephalus, fever, seizure, or meningeal irritation may occur. In this paper, we present an asymptomatic case of such a cyst with imaging evidence of prior rupture, and we review the literature for the likelihood of future complications. We use for illustration a case of a 68-year-old woman with imaging features of a sylvian fissure epithelial inclusion cyst who refused surgical intervention and review the literature for further investigation. Conservative management of our patient has not resulted in a complication in over five years, with the continued offer of surgical resection rejected by the patient. This article suggests the possibility of a safe, non-operative management of dermoid/epidermoid cysts of the sylvian fissure; however, the paucity of literature calls for larger studies yielding reliable data regarding the comparative risk of nonoperative management, including the rate of spontaneous rupture, versus the risk and complication incidence of surgical intervention.