Tiegs‐Heiden, Christin A.

Abstract Objective Ensuring medication delivery to the epidural space is crucial for effective transforaminal epidural steroid injections. Epidural needle placement is determined by injecting a small amount of contrast at the final needle position. The purpose of this study is to illustrate the appearance of contrast flow in the retrodural retroligamentous space of Okada during computed tomography– and fluoroscopy-guided cervical and lumbar transforaminal epidural steroid injections. Design This retrospective study will use a series of cases to demonstrate contrast within the space of Okada during epidural transforaminal steroid injections. Setting Tertiary medical center. Subjects Study subjects are adult patients who underwent transforaminal epidural steroid injection at our institution. Methods Cases were identified through the use of a search engine of existing radiology reports at our institution. Epidural steroid injection procedural reports were searched for the terms “Okada” and “retrodural space.” Images from the procedure were reviewed by the authors (all proceduralists with dedicated training in spinal injections) to confirm the presence of contrast within the space of Okada. Results This case series illustrates six examples of contrast injection into the retrodural space of Okada during cervical and lumbar transforaminal epidural steroid injections. Conclusions Contrast uptake in the retrodural space of Okada may be seen during transforaminal epidural injections. Although relatively uncommon, it is likely underrecognized. It is extremely important that providers who perform transforaminal epidural steroid injections be familiar with this non-epidural contrast flow pattern so they can adjust needle positioning to deliver steroid to the epidural space.

Purpose Understanding all factors that may impact radiation dose and procedural time is crucial to safe and efficient image-guided interventions, such as fluoroscopically guided sacroiliac (SI) joint injections. The purpose of this study was to evaluate the effect of flow pattern (intra- vs. periarticular), patient age, and body mass index (BMI) on radiation dose and fluoroscopy time. Methods A total of 134 SI joint injections were reviewed. Injectate flow pattern, age, and BMI were analyzed in respect to fluoroscopy time (minutes), radiation dose (kerma area product (KAP); µGy m 2 ), and estimated skin dose (mGy). Results BMI did not affect fluoroscopy time, but increased BMI resulted in significantly higher skin and fluoroscopy doses ( p < 0.001). There was no association between fluoroscopy time and flow pattern. Higher skin dose was associated with intraarticular flow ( p = 0.0086), and higher KAP was associated with periarticular flow ( p = 0.0128). However, the odds ratios were close to 1. There was no significant difference between fluoroscopy time or dose based on patient age. Conclusion Increased BMI had the largest impact on procedural radiation dose and skin dose. Flow pattern also showed a statistically significant association with radiation dose and skin dose, but the clinical difference was small. Proceduralists should be aware that BMI has the greatest impact on fluoroscopy dose and skin dose during SI joint injections compared to other factors.

AbstractThe meniscal ossicle is observed in clinical practice, yet there currently is limited information on its potential clinical significance. The purpose of this study was to assess the clinical presentation, imaging findings, and clinical treatment and outcomes of a series of patients identified as having a meniscal ossicle. An institutional database was reviewed to identify knees with a meniscal ossicle. Clinical presentation, magnetic resonance imaging (MRI), treatment, and outcomes were analyzed. Radiographs were graded using Kellgren–Lawrence (KL) scores. MRIs were reviewed for the presence and location of meniscal ossicles and additional knee pathology. Knee arthroplasty rates were recorded with the remaining patients contacted to obtain final International Knee Documentation Committee (IKDC) and Tegner's scores. Failure was defined as conversion to arthroplasty or failing IKDC score (< 75.4). Forty-five meniscal ossicles in 45 patients (26 males and 19 females) with a mean age of 51 years (standard deviation [SD] = 19.0) were included. Pain was the most common presenting symptom (89%). Forty-two patients (93%) had an associated meniscus root tear on MRI. Eighteen percent of patients that did not have an ossicle on initial imaging subsequently developed an ossicle. Mean KL grades progressed significantly from baseline of 1.84 (SD = 1.0) to 2.55 (SD = 0.93 p < 0.01) on final follow-up. Thirty-nine percent of baseline radiographs showed KL grades of less than 2 compared with only 15% of follow-up radiographs (p = 0.04). Mean IKDC score obtained for patients ≤ 60 at an average follow-up of 3.1 years (SD = 3.2) was 65.2 (SD = 19.0). Eight out of 45 patients (18%) had progressed to total knee arthroplasty (TKA) by latest available follow-up. Sixty-two percent of patients met failure criteria at latest available follow-up. The meniscal ossicle is most commonly found in the posterior horn or root of the medial meniscus and is highly suggestive to be sequelae of a posterior root tear. Therefore, the presence of a meniscal ossicle should alert the orthopaedic surgeon to the high likelihood of the patient having a meniscus root tear. These patients have shown to have poor clinical outcomes and worsening arthritis.

AbstractMuscle ischemia and infarction are associated with a variety of pathologic conditions and commonly encountered in busy imaging practices. This article reviews the most common clinical scenarios in which they are seen including compartment syndrome, diabetic myonecrosis, and rhabdomyolysis, focusing on the imaging findings and differential diagnosis for each disease process. Magnetic resonance imaging is increasingly useful in differentiating myonecrosis from muscle ischemia and myositis, and it is highly accurate in diagnosing the most common type of compartment syndrome.